CIRP ANNALS 1992
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STC A |
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Automated sequencing and subassembly detection in assembly planning
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G. Dini, M. Santochi (1)
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STC A, 41/1/1992, P.1
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Keywords: Assemblies, Planning, Subassemblies |
Abstract : This paper describes a procedure for the selection of the subassemblies
and the assembly sequences of a product, applied in an assembly planning
software system named FLAPS (FLexible Assembly Planning System), under
development at the institute of mechanical technology of the University
of Pisa. This procedure is based on a mathematical model of the product,
obtained through the definition of 3 matrices: the interference matrix,
the contact matrix and the connection matrix. The possible subassemblies
are automatically detected by satisfying some mathematical conditions
applicable to these matrices. For each subassembly and for the whole
product, all the possible assembly sequences are generated, whose number
can be successively reduced according to some optimization criteria. At
the end, a meaningful example is reported to show the possibilities of
the method.
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Planning of products assembly and disassembly
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L. Laperriere, H.A. ElMaraghy (1)
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STC A, 41/1/1992, P.5
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Keywords: Process Planning, Assembly, Disassembly, Graph Methods, Optimal Plans |
Abstract : Previous research in assembly process planning focused on the generation
and evaluation of all possible assembly plans for the product under
consideration. While this approach ensures completeness, it is
inefficient, time consuming and costly. This paper presents the results
of our research which aims at improving the efficiency of the assembly
planning process and producing optimal assembly and disassembly plans.
Geometric feasibility and accessibility constraints are introduced to
reduce the size of the directed assembly graph to be searched. Four
criteria have been introduced and formalized to optimize the resulting
assembly plans. These are: stability, number of reorientations,
concurrency of operations, and grouping of similar operations. Graph
search methods which guarantee optimality of plans are briefly
described. Examples of real products are used to illustrate the
generation of: assembly plans, disassembly plans for repair and
maintenance, and plans to recover from assembly execution errors.
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Integrated assembly planning and scheduling - CAPP related issues
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W.H. Elmaraghy / H.A. ElMaraghy (1)
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STC A, 41/1/1992, P.11
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Keywords: Computer Integrated Manufacturing (CIM), Computer Aided Process Planning (CAPP), Production Planning and Control (PPC), Assembly Planning |
Abstract : Responsiveness to unforeseen disturbances on the shop floor is highly
desirable in order to increase throughput, reduce waste and improve
resource utilization and productivity. Such responsiveness requires
changes to process planning systems (CAPP) and production planning and
control systems (PPC). This paper deals with issues related to CAPP and
its integration with PPC. It discusses two modules: a reactive planning
environment (RPE) and an event handler communication system called the
Integrator, developed at McMaster University and the University of
Western Ontario, respectively. Various integration scenarios and their
advantages and disadvantages are presented. The developed modules were
applied to product assembly planning in combination with operations,
from other manufacturing domains, required to complete the product.
Complementary research in production planning and control is carried out
by IPA (Stuttgart) in a collaborative project.
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The integration of CAPP and PPC - The PPC part
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H.J. Warnecke (1), H. Kühnle
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STC A, 41/1/1992, P.15
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Keywords: Computer Integrated Manufacturing, Assembly, Scheduling |
Abstract : The paper introduces concepts for the integration of Computer Automated
Process Planning (CAPP) and Production Planning & Control, PPC). Logics,
benefits and scenarios of functional integration are discusses. Methods
and techniques for the implementation of integration are highlighted.
Based on a general assembly process model, various planning aspects of
PPC such as lot-sizing, scheduling and bottleneck management are finally
shown.
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A knowledge-based system for automated assembly planning
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H.K. Tönshoff (1), E. Menzel, H.S. Park
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STC A, 41/1/1992, P.19
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Keywords: Knowledge Based Systems, Assembly Sequence, Layout Planning, Programming of Robots |
Abstract : This paper presents a computer-aided planning system for automated
assembly cells, which uses the product description to generate assembly
sequences and finally robot programs. For solving the entailed problems
knowledge-based techniques are applied. In order to determine the
assembly sequence, the assembly task has to be described by the jointing
positions between the individual parts and by the assembly technology to
be applied. The multitude of combinational possibilities for the various
connections can be reduced with the help of planning rules. Within the
layout planning, the travel route is optimized to achieve the minimum
cycle time. On the functional level of automatic programming, the
assembly processes are described in terms of their operational
functions. On the language level, the individual functions are then
translated into commands for the specific machines.
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Acoustic test procedures - A powerful method for quality assurance and process monitoring in the assembly
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J. Milberg (1), J. Wisbacher
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STC A, 41/1/1992, P.25
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Keywords: Assembly Systems, Acoustic Emission, Quality Assurance |
Abstract : In many cases, it is necessary to integrate suitable test methods for
process monitoring and quality assurance into automatic assembly
systems. Noise analysis is a comprehensive approach to the analysis of
the various complex interactions between assembly product and assembly
process. This test method is based on the noise pattern characterizing
technical processes. If errors occur in the assembly process, the noise
pattern usually shows characteristic deviations. These can be determined
by comparing the measured noise characteristics to stored reference
data. By means of noise analysis, even complex processes can be
monitored at poorly accessible positions within an assembly system.
Apart from that, this method is highly versatile and flexible, as the
application examples "Process Monitoring of the Assembly of Clip
Elements" and "Assurance of the Assembly Quality of Three-Phase
Generators" show.
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Application of advanced data processing technology for integrated inspection in electronics assembly
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P. Mengel, N. Roth (2), P. Schwartz
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STC A, 41/1/1992, P.29
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Keywords: Flexible Assembly, Integrated Inspection, Acoustic and 3D-Sensorics, Neural Networks |
Abstract : The paper deals with integrated test and quality assurance systems for
monitoring and control of advanced production lines in electro technical
industry. The focus of the paper is on the application of innovative
data processing technologies based on neural networks which are used
both for acoustic signal interpretation as well as for image processing.
By describing examples of their application in the manufacturing of
electro motors and in the assembly of Printed Circuit Boards (PCB) both
the technological approach as well as the conclusions from the
industrial application are discussed.
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Process planning and robotic assembly system design for technical textile fabrics
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G. Seliger (2), C. Gutsche, L.H. Hsieh
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STC A, 41/1/1992, P.33
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Keywords: Technical Textile Fabrics, Robotic Assembly, Process Planning and System Design, Lay-Up, Bonding |
Abstract : Assembly of non-rigid sheet materials represents one of the most
premising but difficult fields in industrial automation. Knowledge about
parts interaction during gripping and joining is a prerequisite for
process planning and design of automated assembly systems. In this paper
part behavior and relevant process parameters are quantified.
Experimental determination of the parameters for the design of needle
and card grippers as well as for determining of joining strategies for
bonding and lay-up of technical textile fabrics is described in detail.
Design tools based on process parameters increase the planning
efficiency. Design fundamentals for needle and card grippers have been
worked out. An example of planning and design for a flexible assembly
system based on the experimental results is shown.
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A simulation system on assembly accuracy
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T. Arai (2), K. Takeuchi
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STC A, 41/1/1992, P.37
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Keywords: Assemblies, Tolerances, Geometric Modeling, Simulation, Selective Assembly |
Abstract : In order to construct a high performance manufacturing line in a short
time, it is inevitable to simulate manufacturing process from the view
point of accuracy. This paper proposes a method of evaluating the
accuracy of assembled product based on a geometric model. Machining
errors, assembly errors and measuring errors are modeled as probability
distribution functions in Monte Carlo method. Selective assembly is
simulated, and the number of the classification is evaluated. The result
indicates the number of the classes improves the assembly accuracy, but
decreases slightly the efficiency of the total assembly line.
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Screw fastening in flexible automated assembly with computer-integrated process control
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K. Feldmann (2), M. Steber
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STC A, 41/1/1992, P.41
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Keywords: Flexible Assembly, Process Control, Quality Assurance |
Abstract : A special challenge in flexible automated assembly systems is still to
optimize the screw fastening. Therefore a computer integrated system was
developed, which helps to plan and control the screw fastening process.
The concept was tested systematically in an assembly cell with a gantry
robot, which manipulates a bolting spindle. The developed program can
control several bolting processes simultaneously. Furthermore, relevant
process data can be recorded and stored. In case of process failures the
additional monitoring system supports the supervisor to solve the
problems. This special assembly cell is part of a computer-integrated
model factory at the University of Erlangen.
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A comparison of control paradigms for adhesive dispensing
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A.A. West, J.C. Hinde, D.J. Williams (2)
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STC A, 41/1/1992, P.45
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Keywords: Adhesives, Assembly, Controllers |
Abstract : This paper compares implementation styles for elements of the solution
of a control problem encountered in the manufacture of electronic
assemblies. The implementation studies include the application of rule
based control within an object oriented environment, a neural network
based system equivalent to elements of the rule based process controller
and a design study for a control system implemented in a conventional
procedural language. The control task is the control of the accurate
dispensing of the small quantities of adhesive used to secure surface
mount components to mixed technology printed circuit hoards and
therefore allow the assemblies to tie wave soldered.
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STC C |
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New approaches to characterising the performance of coated cutting tools
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W. König (1), R. Fritsch, D. Kammermeier
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STC C, 41/1/1992, P.49
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Keywords: Coatings, Physical Vapor Deposition (PVD), Wear Resistance |
Abstract : The paper deals with the properties of PVD and CVD coatings deposited on
HSS or cemented carbide tools. Titanium-based ternary layers form the
main topic. The substrate and coating properties related to straight and
interrupted cutting of quenched and tempered steel are characterized.
Differences in performance between coated tools are explained through a
separate consideration of substrate and coating influences. In addition,
the paper describes a new approach to analyzing the effects of the
thermal properties of the "coated tool" composite on the type and
progress of wear.
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Machinability of particulate aluminium matrix composites
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N. Tomac, K. Tonnessen / F.O. Rasch (1)
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STC C, 41/1/1992, P.55
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Keywords: Cutting, Composites, Wear |
Abstract : Mechanical and physical properties of light metal matrix composites
(MMC) indicate that these materials could play a significant role in
applications for engineering components. The aim of this investigation
has been to enhance the knowledge about the machinability of a specific
particulate aluminum matrix composite (AlSi7Mg) alloy reinforced with 14
vol%37; SiC. The high percentage of hard silicon carbide (2700 HV) which is
used to reinforce PAIMC makes machining operations very difficult. The
hard SiC particles are forced against the tool, causing excessive
abrasive flank wear. The main objects of the investigations were tool
wear, cutting forces and surface roughness.
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High performance machining of SiC whisker reinforced aluminum composite by self-propelled rotary tools
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P. Chen / T. Hoshi (1)
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STC C, 41/1/1992, P.59
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Keywords: Composites, High Speed Machining, Tool Life |
Abstract : Aiming to machine a SiC whisker reinforced aluminum composite for the
sake of high production rate and high cost efficiency, the
self-propelled rotary tool was proposed and evaluated in this study.
Experimental results show that the rotary tool made of carbide exhibits
superior wear-resistance comparable to the diamond tool, that tool life
of carbide has been extended dozens of times by rotary cutting, that the
rotary tool bears neither built-up edge nor flank build-up, and that the
radial thrust cutting force component of the rotary tool is 30-40%37; lower
than that of the fixed circular insert. The rotary tool is found to be a
high performance cutting tool for machining of the composite.
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Machining of fibre and particle reinforced aluminium
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L. Cronjäger (1), D. Meister
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STC C, 41/1/1992, P.63
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Keywords: Drilling, Milling, Composites |
Abstract : The machining of metal matrix composites causes problems because the
tool wear, due to the hardness of the ceramic Fibers and particles, is
extremely high. The use of high speed steel tools (HSS) is not possible.
Polycrystalline diamond (PCD) tipped tools are often necessary to
guarantee a dimensional stability and an economic machining.
To diminish the tool wear the relation of the particle size, the
PCD-grain size and the feed rate is important. The application of a
coolant or lubricant can effect a higher tool wear.
In spite of the extreme tool wear the machining quality is often better
than to the case of not reinforced aluminum.
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A new approach to the theoretical analysis of surface generation mechanism in machining
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G. Byrne (2)
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STC C, 41/1/1992, P.67
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Keywords: Machining, Surface Properties |
Abstract : This paper reports on a new theoretical approach and the development of
a computer simulation program for the analysis of engagement mechanics
and surface generation mechanisms in machining under geometrically
defined conditions. Based on the example of external cylindrical
turning, a model of the work hardening mechanisms which arise in the
surface layer during machining has been developed. This idealized model
comprises two sub-models. In the first sub-model the geometrical and
kinematic inter-relationships in the zone of cutting are described. The
second sub-model describes as a first approach the behavior of the
workpiece material during chip removal. Both sub-models form the basis
of a computer simulation program which allows the prediction of
engagement conditions, micro-hardness level and surface layer damage.
From the practical, industrial machining point of view, an understanding
of surface generation mechanisms takes on renewed importance in order
that environmentally acceptable machining processes can be developed in
the future. The work is also of direct relevance to precision and
ultra-precision machining.
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Comprehensive chip form classification based on the cutting mechanism
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K. Nakayama (1), M. Arai
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STC C, 41/1/1992, P.71
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Keywords: Cutting, Cutting Tool Geometry, Chip |
Abstract : For the logical control of the chip form in machining operation, chip
forms are classified comprehensively, and the conditions to control the
form are indicated. Due to the developments in cutting tool and cutting
technology, possible ranges of variation in the conditions and the form
of chips produced have become very wide. To meet such situation, the
chip form diagram presented before by one of the authors is expanded.
Essential meanings of the direction of side curling and chip flow angle
on the chip form and the proceeding of helical chip are made clear. A
projection on tool face plays important role by changing the line of
tool-chip separation and, accordingly, the form and proceeding of
helical chip.
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On the problem of thermoelectric current in metal cutting
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K. Uehara (1), M. Sakurai, T. Ikeda
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STC C, 41/1/1992, P.75
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Keywords: Turning, Tool Wear, Insulation |
Abstract : The behavior and the effect of thermoelectric current which flows
through tool-chip interface in metal cutting has been a obscure problem
for a long time. The aim of this paper is to find out the path of
thermoelectric current near the cutting edge and to clarify its
influence on the tool wear and cutting mechanism. The path of electric
current was determined using an analogous technique. It was found that
the path is strongly influenced by tool insulation, tool wear,
temperature distribution of tool chip-interface and application of
external electricity. These findings explain the results of cutting
experiment well.
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A statistical model for prediction of tool life as a basis for economical optimization of the cutting process
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T.E. Carlsson, F. Strand / B. Lindström (1)
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STC C, 41/1/1992, P.79
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Keywords: Adaptive Control, optimization, Tool Wear |
Abstract : The paper is dedicated to the implementation of statistical optimization
of the cutting process by identification and prediction of the tool
condition and lifetime. A statistical model is presented which uses
ideas from the theory of reliability and statistical quality control.
Since the model is consistent with the Taylor equation, it can easily
utilize existing information about relations between cutting data and
tool life. A control strategy, which is based on the model, is put
forward. Results from experimental tests of the statistical model and of
the influence on the wear rate due to feed variations as well as of the
performance of the control algorithm are presented.
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Development of a deep hole boring tool guided by laser
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A. Katsuki, H. Onikura, T. Sajima, T. Akashi / T. Matsuo (1)
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STC C, 41/1/1992, P.83
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Keywords: Boring, Laser Beam Application, Adaptive Control |
Abstract : A laser-guided BTA tool has been developed with the purpose of
preventing the axial hole deviation in deep hole boring. To examine the
performance of this system, two kinds of experiments were carried out
using prebored duralumin workpiece. The first experiment was to examine
if the tool can be precisely manipulated by computer. The second was to
investigate if the tool can follow the target. The target is located in
front of the tool and its position changes in the normal plane to the
machining axis. The results show that the tool can turn its course to
correct hole deviation.
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Cutting conditions and work material state identification through acoustic emission methods
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R. Teti (2), U. La Commare (2)
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STC C, 41/1/1992, P.89
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Keywords: In-Process Monitoring, Acoustic Emission, Turning |
Abstract : This paper examines the problem of in-process monitoring of metal
cutting operations carried out on aluminum alloys for aeronautical
applications. Turning tests were conducted on annealed and heat treated
aluminum alloy bars, using carbide tools. For both work material
conditions, different combinations of cutting parameters were used.
During cutting tests, acoustic emission (AE) and cutting force sensor
data were detected and processed. The comparison between AE responses
from the annealed and heat treated aluminum alloys allowed, with the
help of force sensor data. to verify the applicability of AE and sensor
fusion techniques for in-process and real time identification of work
material state.
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Acoustic emission feedback for precision deburring
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D.A. Dornfeld (2), V. Lisiewicz
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STC C, 41/1/1992, P.93
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Keywords: Acoustic Emission Sensor, Deburring Automation, Feedback Control |
Abstract : Deburring operations account for a considerable portion of the cost of
machined components and there have been efforts to automate deburring
for some time. This has been done with robots carrying deburring tools
and sensor feedback for tacking the edge. The deburring and chamfering
of precision components is complicated by the fact that the burr may be
very small (0.040 mm or less) and conventional sensing techniques for
burr following such as measurement of force on the deburring tool are
unreliable due to low metal removal rates. Acoustic emission has been
under development as a sensing technique for precision deburring
feedback. This paper will establish the basis for use of acoustic
emission in chamfering and deburring. The results of recent research to
develop and evaluate a signal conditioning and control strategy for
chamfering and deburring 6061-T6 aluminum will be presented.
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Detection of cutting edge breakage in turning
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K. Jemielniak / M. Szafarczyk (1)
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STC C, 41/1/1992, P.97
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Keywords: Tool Life, Brittle Fracturing, Detection, Cutting Forces |
Abstract : The paper presents e digital detector of the cutting edge chipping or
breakage based on the characteristic variation of the cutting force,
associated with brittle catastrophic tool failure. The results of tests
of the detector operation, during which a laboratory dynamometer and
industrial force sensors have been used are also presented.
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Influence of high pressure flushing through the rake face of the cutting tool
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R. wertheim (1), J. Rotberg, A. Ber (1)
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STC C, 41/1/1992, P.101
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Keywords: Chip, Coolant, Tool Life, Tool Material, Wear |
Abstract : The influence of flushing in metal cutting including flow rate,
composition and type of coolant, coolant pressure and direct on, is the
subject of many investigations. In the current study high pressure flow
was used, penetrating through the cutting tool's rake face and reducing
the temperatures in the most critical area. During the investigation the
pressure was increased up to 25 bar. Mainly grooving operations were
investigated, in which chip symmetry simplifies fine analysis. It was
found that flow rate and pressure have a significant influence on tool
life and wear behavior as well as on the chip shape and the
metallurgical structure of the chip itself. The narrowing and curling
effect of the chip, improving chip exit from the slot, is viewed as
related to temperature reduction.
The investigation covered different cutting tool materials and different
workpiece compositions. It was found that the phenomenon of built-up
edge was minimized, especially when machining stainless steel and
similar high alloy materials.
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Tooth chipping during band sawing of steel
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H. Chandrasekaran (2), H. Thoors, H. Hellbergh, L. Johansson
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STC C, 41/1/1992, P.107
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Keywords: Band Saws, High Speed Steels, Heat Treatment, Stress Analysis, Micro-Chipping |
Abstract : The results from a research study on tooth chipping during band sawing
of quenched and tempered steel with HSS tipped bi-metal saws, are
presented here. Research efforts were directed to develop a convenient
reference sawing test to quantify the tooth chipping phenomenon.
Subsequently saw tests were carried out to investigate the influence of
saw material composition, processing route (powder and conventional),
heat treatment and saw teeth stresses (FEM) upon its chipping propensity.
The study shows the importance of correct heat treatment from the point
of view of teeth toughness as exhibited during sawing. Here conventional
and PM HSS variants displayed different sensitivity to heat treatment
and chipping, irrespective of comparable hardness or carbide content.
Tire presented information could well serve as the basis for the closer
study of the micromechanical and material aspects of saw teeth
performance in band sawing.
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Measurements on the dynamic behaviour of modular milling tools
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J.A.W. Hijink, A.C.H. Van Der Wolf (1)
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STC C, 41/1/1992, P.113
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Keywords: Dynamic Tests, Cutting Forces, Milling Cutters |
Abstract : To compare newly designed modular tooling-systems, a number of these
systems have been used in order to compare the dynamic behavior. The
tools were measured dynamically, and three different cutting tests were
performed. As a result of these tests a certain correlation between
dynamic flexibility and cutting performance could he found.
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Molecular dynamics analysis as compared with experimental results of micromachining
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S. Shimada, N. Ikawa (1), G. Ohmori, H. Tanaka, J. Uchikoshi
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STC C, 41/1/1992, P.117
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Keywords: Cutting, Micromachining, Computerized Simulation |
Abstract : An attempt is presented on the molecular dynamics (MD) analysis of
nanometric chip removal process in micro-cutting. Comparison shows a
fairly good agreement between the chip morphologies, the cutting forces
and the specific energy in both MD simulation and micro-cutting
experiments. It is also shown that MD simulation can be applied to the
analysis of thermal field in metal cutting process with the introduction
of suitable scaling on the gradient in thermal field which is affected
by the thermal conductivity of the workmaterial.
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Atomic-scale cutting in a computer using crystal models of copper and diamond
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T. Inamura, N. Takezawa / N. Taniguchi (1)
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STC C, 41/1/1992, P.121
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Keywords: Simulation, Micromachining, Cutting |
Abstract : A method of computer simulation based on a quasi-static computation has
been proposed to analyze nanoscale cutting. The results of simulation
show that, though the cutting mechanism depends on both the crystalline
orientation of the workpiece and the interatomic potential between the
tool and workpiece materials, discontinuous change of cutting force as
well as impulses in the cutting temperature are commonly observed in all
cases. The results obtained by a polycrystal workpiece indicate that the
plastic deformation in metal first occurs along grain boundaries and
then propagates into each grain.
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Fuzzy patten recognition for tool wear monitoring in diamond turning
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T.J. Ko, D.W. Cho, J.M. Lee (2)
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STC C, 41/1/1992, P.125
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Keywords: Diamond, Tool Wear, Fuzzy, Pattern Recognition |
Abstract : In this paper, to monitor single crystal diamond tool wear in
ultraprecision machining process, a fuzzy pattern recognition technique
was introduced. Some selected features to partition the cluster of
pattern were obtained from time series AR modeling of dynamic cutting
force signals. The wear on a diamond tool edge appears to be
classifiable into two types, one of which is micro-chipping and the
other gradual, both very small quantifies to detect compared to
conventional tool wear. In this regard, a fuzzy technique in pattern
recognition, which considers the ambiguity in classification as well as
the weakness of the cutting force variation, was used for monitoring the
diamond tool wear status.
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Chip formation mechanism in microcutting of an amorphous metal
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K. Ueda (2), K. Manage
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STC C, 41/1/1992, P.129
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Keywords: Cutting, Amorphous Materials, Finite Element Method |
Abstract : The chip formation mechanism of an amorphous metal is elucidated by
means of in-situ scanning electron microscope observation and
Rigid-Plastic Finite Element Method (RPFEM). The chip morphology of the
amorphous metal exhibits typical lamellar structure due to periodical
formation of the localized shear band. The chip formation process is
simulated by the RPFEM with considering adiabatic deformation in the
primary shear zone. The simulation results including the lamellar
structure formation process, the lamella spacing and the angle of the
localized shear band are in good agreement with experiment results. The
cutting force and the surface integrity are also discussed.
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Application of sintered plastics to a pourous vacuum chuck for diamond turning of aluminum magnetic discs
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Y. Tani, T. Ohshima, H. Sato (1)
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STC C, 41/1/1992, P.133
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Keywords: Diamond Turning, Aluminium, Plastics, Waviness, Acceleration |
Abstract : Urethane vacuum chucks which are in use for diamond turning of aluminum
magnetic discs because of their high friction coefficient and high
damping ratio have problems in that swelling by a coolant and the
nonuniformity of the supporting rigidity due to the suction grooves
deteriorate the form accuracies of workpieces. Thus, a sintered porous
chuck made of fluororesin has been developed. The investigation of the
mechanical features of the chuck indicated that the chuck was only
slightly deformed by vacuum suction and loading and that it had an
adequate friction coefficient and adequate bonding strength onto the
chuck body for diamond turning. Then, diamond turning of aluminum discs
was carried out using a hard aluminum chuck, a urethane soft chuck and
two types of fluororesin porous chucks. Consequently, the cutting using
a fluororesin chuck achieved better straightness and less acceleration
of a turned surface than that using any other chuck.
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A study on damaged layer remaining in diamond mirror cut surface
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K. Horio, T. Kasai, Y. Ogata, A. Kobayashi (1)
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STC C, 41/1/1992, P.137
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Keywords: Ultra-Precision Machining, Residual Stresses, Diamond Tools |
Abstract : Residual stresses which remains in diamond mirror cut surface is
discussed. After diamond cutting of very thin aluminum alloy workpiece.
measurement of its deflection with repetition of slight elimination by
chemical etching of damaged layer have been done. With this technique,
we can calculate the magnitude of the residual stresses at any depth
from the surface. It was found that the residual stresses is affected by
the sharpness of a diamond tool, so the residual stresses becomes large
with cutting length. Also magnitude of the residual stresses is
different by direction of cutting surface such as along to or
perpendicular to cutting.
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Ultraprecision ductile cutting of glass by applying ultrasonic vibration
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T. Moriwaki (2), E. Shamoto, K. Inoue
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STC C, 41/1/1992, P.141
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Keywords: Brittle-Ductile Transition, Ultra-Precision Machining, Ultrasonics |
Abstract : Ultraprecision ductile cutting of glass is realized by applying
ultrasonic vibration to a single crystal diamond tool in the cutting
direction. It is clarified by grooving experiments that the critical
depth of cut for ductile cutting is increased and the surface profile of
diamond cutting edge is better transferred to the cut groove as compared
to the conventional cutting. The transparent surface of soda-lime glass
w4-1 surface roughness of 0.03 mm Rmax is obtained by face turning. The
work is considered as a contribution to the ultraprecision machining of
brittle materials.
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Determination of tool cutting capacity
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S. Enache (1), E. Strajescu, I. Tanase, C. Opran
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STC C, 41/1/1992, P.145
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Keywords: Cutting Capacity, Mathematical Model |
Abstract : In the work, the mathematical model and the results of the experimental
researches performed are shown, in order to establish the partial and
global tool cutting capacities. They enable the most adequate tools to
be chosen, according to the imposed requirements. At the same time, the
best cutting conditions can be chosen depending on the concrete priority
requirements, so that both the reasonable tool exploitation and
respectively, the attaining of best figures of the imposed parameters
and technical-economical indices could be assured. Finally, some results
of the experimentally performed researches are presented, in the case of
cutting: with metallic carbide tips armed turning tools, with twist
drills, having different forms of the active part, and with metallic
carbide plates armed and milling cutters. The results obtained,
emphasize new methods and ways to increase the tool cutting capacity.
|
|
Macro plastic deformation of cutting edge - A method for maximum utilization of cutting tool
|
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E. Kuljanic (1)
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STC C, 41/1/1992, P.151
|
|
Keywords: Plastic Deformation, Sensors, Turning, Tool Wear, Productivity Increase, Surface Roughness |
Abstract : This paper investigates the macro plastic deformation of the cutting
edge and the material near the cutting edge in rough turning. It was
found that the macro plastic deformation takes place approximately three
seconds after the start of cutting, when the single point cutting tool
is not able to cut properly, the surface roughness of the machined
surface increases and vibrations appear. A method for maximum
utilization of single point cutting tool and tool selection for rough
turning, grooving etc. by using the information about the macro plastic
deformation of the cutting edge are proposed. Both the way of measuring
the macro plastic deformation and how the macro plastic deformation can
be detected by means of feed cutting force is presented. Acoustic
emission sensors or sensors systems could be used for detecting the
macro plastic deformation of the cutting edge.
|
|
Some basic relationships for identification of the machining processes
|
|
J. Peklenik (1), A. Jerele
|
|
STC C, 41/1/1992, P.155
|
|
Keywords: On-Line Process Identification, Transfer Function, Propagating Surface Interface |
Abstract : Research into the machining processes was since F.W. Taylor very
intensive, trying to understand and describe the process as a complex
object of control. Its modeling was based predominately on the
deterministic approach, and well known laws of classical physics.
This contribution reports on some research results, where the process
represents a part of the close loop machining systems and is described
as a propagating and frictional surface interface. Its identification is
based on stochastic inputs and outputs, related to the structure of the
material. An attempt is made to develop the process transfer function,
determining the gain factors, the process frequency bandwidths and the
damping factors in relation to the cutting speeds and structural
characteristics of the materials.
|
STC Dn |
|
Development of new methodology for mechanical design by symbolized elements with movement
|
|
K. Iwata (1), E. Matsuo, M. Onosato
|
|
STC Dn, 41/1/1992, P.161
|
|
Keywords: Design, Mechanism |
Abstract : The concept of "Mechanism Diagram" is introduced in order to realize the
quick understanding of mechanism in mechanical design. Mechanism Diagram
is constituted by the connection of "symbolized elements with movement
", which are derived by analyzing kinematic relations of mechanical
elements in machines. A drawing system for Mechanism Diagram is also
developed. The result of experiments by using it shows that Mechanism
Diagram can remarkably reduce time for understanding a complicated
mechanism.
|
|
The product structure - The backbone of CIM
|
|
L. Lindberg, E. Agerman (2)
|
|
STC Dn, 41/1/1992, P.165
|
|
Keywords: Design, Data Model, Product Structure |
Abstract : In this paper we argue that the product structure should be used as the
backbone for the modeling and documentation of the product. First a
general architecture of a Technical Information System, TIS, based on
Functional Systems is presented. Then three major subsystems of the TIS
are identified, and one of these, the Product Structure System is
discussed in greater derail. The product structure is shown to be in a
sense both complete and stable, thus providing a foundation for a true
CIM system. A simple, yet versatile, data model is presented, allowing
variants and views of the product to be represented.
|
|
The 'constructive deductive' design approach - Application to power transmissions
|
|
J.P. Van Griethuysen / A. Wirtz (1)
|
|
STC Dn, 41/1/1992, P.169
|
|
Keywords: Design, Modelling, Bottom-Up Design, CAD |
Abstract : The constructive deductive approach is a "bottom-up" optimized design
method. The method proposes a sequence of logical constructive rules up
to the product solution from the functional specifications. It is easy
to automate in an intelligent CAD expert system as it is sequential. A
description of this approach will precede an application to demonstrate
the first step of this method : the design oriented analysis.
|
|
Probabilistic aspects of axiomatics
|
|
P. Tatray / G. Sohlenius (1)
|
|
STC Dn, 41/1/1992, P.173
|
|
Keywords: Axiomatics, Quality, Design Theories, Top-Down Design |
Abstract : Axiomatics is a design theory that is partly based on probabilistic
concepts. It proposes two axioms. The first is dealing with coupling of
functions in the design, and the second with simplicity and probability
of success. Exploring the probabilistic aspects of it leads to a partial
reformulation and reinterpretation of Axiom 2, shows where the limits of
its application could lie, and shows an alternative way of defining
independency in Axiom 1. We can even prove, that simplest is best,
combining full independence according to Axiom and the old and new
formulation of Axiom 2. Other measures of complexity than given by Axiom
2^ are also discussed, and some possible further research directions are
defined.
|
|
Integration of CAD/CAM and production control for sheet metal components manufacturing
|
|
S. Tilley / H. Van Brussel (1)
|
|
STC Dn, 41/1/1992, P.177
|
|
Keywords: images/cirpfichiers/annals/ CAD/CAM, Production Planning and Control, Features, Data Bases |
Abstract : The paper deals with the computer integrated manufacturing and
production of sheet metal components. The system developed, aims at
giving a high degree of flexibility in choosing the manufacturing
resources. Typically the selection of machines and tools is made at the
latest possible moment. The decisions are taken using the latest
information from the shop floor. The system contains a central database
for storing and exchanging information amongst all modules, using
parametrical, technological features for description of parts tools and
machines. The monitoring is built into the medium and short term
scheduler thus allowing the continuous control of orders.
|
|
Concurrent design and process planning of rotational parts
|
|
D. Domazet, S. lu (2) / M. Kalajdzic (1)
|
|
STC Dn, 41/1/1992, P.181
|
|
Keywords: Concurrent Engineering, Computer Integrated Manufacturing (CIM) |
Abstract : In this paper, a system for concurrent engineering of rotational parts
is proposed. The paper describes the first modules which have been
developed and perform product design, process planning and
manufacturability analysis. A feature-based design system generates the
product model with multiple representations, including both symbolic and
object-oriented. A Lisp-based frame format allows easy transfer of
product data to the process planner, also developed in a Common Lisp
environment. Using object-oriented programming techniques, a blackboard
architecture, and multiple rule-bases, a process plan can be generated
during all design stages. This allows the designer to verify his design
from a manufacturing perspective and, if necessary, modify it in the
early stages. Manufacturability analysis is based on the generated
process plan and actual process data inventory.
|
|
Design by using machining operations
|
|
M.A.S. Arikan (2), O.H. Totuk
|
|
STC Dn, 41/1/1992, P.185
|
|
Keywords: Design, Milling, Part Programming |
Abstract : Since every designed part will be manufactured afterwards, it is
important to consider also the manufacturing aspects at the design
stage. Machining, which is one of the basic manufacturing processes, is
the removal of certain selected areas, in order to obtain a desired
shape or finish. Therefore, it can be considered as removing some
defined geometric elements from a solid object, wherein geometries of
these elements are determined by the individual machining operations. A
database comprising the geometric elements related to machining
operations is constructed, and parts are formed by subtracting these
elements from a simple solid object, like a rectangular prism or a
cylinder. The database comprises the geometric elements related to
available operations on a 2 1/2 axis CNC milling machine. For design of
the part by using this method, an interactive computer program with
graphical input and output is developed. The program also has modules
for sequencing the machining operations according to a prescribed
decision logic, for automatic or manual selection of cutting tools for
corresponding operations. for calculation of machining parameters by
using empirical relations, for creation and usage of personal databases
for cutting tool and machining data, and for preparing the NC program
and transmitting it to the milling machine for machining of the part.
|
|
A feature-based classification scheme for fixtures
|
|
A.Y.C. Nee (1), A. Senthil Kumar, S. Prombanpong, K.Y. Puah
|
|
STC Dn, 41/1/1992, P.189
|
|
Keywords: Jig and Fixtures, Classification, Codes and Coding, Group Technology, Computer-Integrated Manufacturing |
Abstract : This paper presents a feature-based classification scheme for fixtures
using a 3D solid modeler, a feature extractor and an object-oriented
expert system shell. Its intended use lies in variant fixture designs as
well as its association with machining operations, machining
environment, cutting tools and workpiece features. The operations begin
with a solid model where machining features are extracted and grouped
into setups based on machining directions and tolerance factors. A
knowledge base is used to infer the operations involved and the cutting
tools required for a given machining environment. Different classes and
sub-classes of fixtures are identified based on setups, operations, and
fixturing rules. Instead of using numerical taxonomy, the fixture is
coded in feature-based symbolic representations which can be compared
easily for its similarity with existing fixtures.
|
|
Product design evaluation based on effect of shape errors for part assembly
|
|
F. Kimura (2), H. Suzuki, K. Takahashi
|
|
STC Dn, 41/1/1992, P.193
|
|
Keywords: Design Evaluation, Shape Error Analysis, Dynamic Simulation |
Abstract : One of the machine design objectives is to maximize the functionality
under the constraints of manufacturability. It is desirable for
designers to be able to analyze the effect of geometrical errors due to
manufacturing processes on the functional behavior of assemblies. We
propose a method to evaluate the motion of an assembly of parts with
geometrical errors. We make idealization of geometrical errors
considering typical machining errors, and solve equations of motion of
objects under the gravity and friction force from contact constraints by
using Linear Programming Method. The result of calculation is useful for
evaluating the effect of shape errors on the accuracy of the motion of
assemblies.
|
|
Tolerance synthesis to support concurrent engineering
|
|
R.G. Wilhelm, S.C.Y. Lu (2)
|
|
STC Dn, 41/1/1992, P.197
|
|
Keywords: Tolerance Synthesis, Concurrent Engineering, Computer-Aided Design |
Abstract : Geometric tolerances are critical in many phases of product and process
design, linking design goals and manufacturing capabilities. With an
appropriate representation, geometric tolerances can provide flexibility
in concurrent engineering so that, when complete information about
geometry and tolerances is available, several different fabrication
strategies can be considered and fairly compared. This paper presents a
framework and computer implementation that provides automated methods
for geometric tolerance synthesis. This approach directly supports
design synthesis since design details can be referred from the tolerance
relationships which must hold for particular requirements. Automated
analysis of completed designs and design checking is also possible with
this approach.
|
|
Product modelling and "information integrated" engineering systems
|
|
T. Kjellberg (2), H. Schmekel
|
|
STC Dn, 41/1/1992, P.201
|
|
Keywords: Product Modelling, Reference Models, Product Realization, "Information-Integrated" Systems |
Abstract : The integration of computer represented engineering concepts together
with geometric model concepts will be discussed in order to realize
future product modeling systems. It will provide for "information
integrated" systems in engineering and more advanced tools for
communication to realize concurrent product realization. What then can
be achieved will be reasoned upon. Implemented examples and developed
reference models will show how product models with engineering
terminology and concepts can be represented in the computer.
|
|
Knabling use of engineering terminology in product models and user interfaces of CAD/CAM systems
|
|
L. Wingard, p. Carleberg, T. Kjellberg (2) / G. Sohlenius (1)
|
|
STC Dn, 41/1/1992, P.205
|
|
Keywords: Features, Product Modelling, Interactive Design Systems |
Abstract : This paper presents an approach to introducing engineering terminology
in product models and user interfaces of CADCAM systems. It describes
how we have utilized forth features and engineering elements in order to
represent engineering knowledge more naturally in product models. This
gives us a method for realizing user interfaces in which an application
specific and user adapted engineering terminology is used. A CADCAM
Framework for integration of general software packages into a
distributed CADCAM system is also suggested. Finally, some aspects of
the suggested approach, collected from a limited test implementation and
from discussions with an industrial partner are discussed.
|
|
Hypermedia as a design tool with application to design of fluid film journal bearings
|
|
W.B. Rowe (1), K. Cheng
|
|
STC Dn, 41/1/1992, P.209
|
|
Keywords: Design, Hypermedia, Artificial Intelligence |
Abstract : This paper describes a hypermedia based intelligent system for design
with particular reference to fluid film journal bearings. It is
considered that this approach has potential for much wider application
in design. The .system was developed by integrating hypermedia,
artificial intelligence and intelligent database technologies, together
with conventional design techniques.
|
|
Application of adaptive resonance networks for conceptual design
|
|
S.R.T. Kumara (2), S.V. Kamarthi
|
|
STC Dn, 41/1/1992, P.213
|
|
Keywords: Conceptual Design, Group Technology, Neural Networks |
Abstract : Conceptual design is the most important and creative phase of the design
process which demands the knowledge, intuition, and imagination of a
designer. The success of the designer in this phase of design depends
upon his ability to recall a family of previous design problems which
are similar to the current problem and apply the previously discovered
solutions. In this paper the application of Adaptive Resonance Theory
networks for the creation of families of design problems, characterized
by their functional requirements is examined. A comparison of this
method is maid with k-mean clustering algorithms. It is found that the
Adaptive Resonance Theory networks provides the means for the dynamic
creation of families of design problems which cannot be obtained by
using conventional clustering algorithms.
|
|
Intelligent CAD of Box-type machine components
|
|
X.N. Feng (2), Y.Z. Zhang
|
|
STC Dn, 41/1/1992, P.217
|
|
Keywords: Computer Aided Design, Expert Systems, Design, Drawing |
Abstract : The basic principles and methodologies of intelligent CAD for box-type
machine components are described in this paper. A special developed
three dimensional solid modeling graphic software is used to construct
on screen the model of machine component to be designed, and to extract
the graphic information for generating two dimensional working drawing
of box-type machine, component. The necessary graphic entities which
should be dimensioned without any redundancy to define the model of
machine component unequivocally are determined. Expert systems are used
to decide which sizes should be dimensioned and how to distribute all
the sizes to each view and section view in the run dimensional working
drawing. The CAD system then is able to generate automatically the
corking drawing of box-type machine component qualified for
manufacturing. It also be described the key strategies including
dimension redundancy analysis, the principles of expert systems used for
reasonable distributing and dimensioning of sizes etc.
|
STC E |
|
About the evolution of the wire tool performance in wire EDM
|
|
D.F. Dauw (2), L. Albert
|
|
STC E, 41/1/1992, P.221
|
|
Keywords: Wire, Cutting Speed, Accuracy, Roughness, Precision |
Abstract : Since the commercial introduction of wire EDM on the market, end 1969
begin 1970, the overall performance of the wire EDM has undergone a
tremendous evolution. Six major contributing factors nave been
responsible for this important change. One of these, the wire tool
electrode has been improving substantially yielding an enormous increase
of the overall performance (cutting speed, cutting accuracy, precision,
cost etc.). The paper deals with an analysis of the six contributing
factors. Attention is given in particular to one of these factors, the
wire tool itself. The several types of ware are compared twin their
metallurgical aspect. Their physical composition and .relative
performance are analyzed and a cost to performance ratio is given for a
series of wires considered. As a conclusion, it is shown that the wire
tool, a though often considered as an evident EDM accessory has
influenced very substantially the EDM wire cutting performance.
|
|
Observation of the arc column movement during monopulse discharge in EDM
|
|
M. Kunieda, H. Xia, N. Nishiwaki / N. Kinoshita (1)
|
|
STC E, 41/1/1992, P.227
|
|
Keywords: EDM and Discharges |
Abstract : This paper describes the results of the detection and observation of arc
column movement during monopulse discharge and the movement of the arc
column subjected to a transverse magnetic field in the EDM process. It
is found that not only the cathode spot but also the anode spot moves at
a high speed over the electrode surfaces during a monopulse, and that
the moving patterns of the anode and cathode spots are the same.
Besides, the area over which/ /the arc column moves becomes broader with
the progress of the discharge, which coincides well with observation of
the resulting craters.
|
|
Investigation on the optimum carbide content and machining condition for wire EDM of zirconia ceramics
|
|
T. Matsuo (1), E. Ohshima
|
|
STC E, 41/1/1992, P.231
|
|
Keywords: Wire EDM, Zirconium, Ceramics, Cutting Rate |
Abstract : Wire EDM has been performed on conductive zirconias containing 23 to 45
vol%37; NbC or TiC, and thus, the optimum carbide content was clarified.
The machining rate and surface roughness for various pulse durations and
duty factors were evaluated, and consequently, the optimum machining
conditions for the wire EDM were discussed. It is obvious that the
maximum machining rate can be obtained with about 28-30 vol%37; NbC or TiC
content, and that there exists the optimum duty factor from a standpoint
of machning rate. Also, the effect of second cut on the machining rate
and surface roughness was investigated.
|
|
On the electro-discharge machining of ceramic plasma-sprayed steel plates
|
|
A.G. Mamalis (1), N.M. Vaxevanidis, D.I. Pantelis
|
|
STC E, 41/1/1992, P.235
|
|
Keywords: Surface Integrity, EDM, Plasma-Sprayed Ceramics, High Strength Steels |
Abstract : The present work is a follow-up of the extensive research on "surface
integrity of mechanically and/or thermally worked steel grades"
undertaken by the authors and also a first step into an investigation of
the possibilities and limitations of successfully applying EDMachining
on non metallic materials of great industrial importance such as
electroconductive ceramics,/ /ceramic-metal and carbon-fibre reinforced
composite. In this paper we report on the application of EDMachining to
plasma-sprayed WC-Co coating on HSLA steel substrate. The influence of
the intense thermal impact due to EDM upon the main features of the
resulted surface is examined in terms of microgeometry/ /and surface
topography, microhardness variation and metallurgical changes in the
surface and the subsurface layers: their dependence on the main
processing parameters is examined and discussed. Comparison is also/
/made with high-strength steel grades EDMachined under the same conditions.
|
|
Improved jet flushing for EDM
|
|
T. Masuzawa (2), X. Cui, N. Taniguchi
|
|
STC E, 41/1/1992, P.239
|
|
Keywords: EDM |
Abstract : Jet flushing is the most popular type of flushing for EDM. However, it
is usually applied with the nozzles fixed at positions which are decided
on the basis of the operator's experience. In this paper we propose a
dynamic jet flushing method with moving nozzles that sweep along the
outline of the EDM gap. Experimental results clarify the effectiveness
of this method on the precision of machining. A method for calculating
the debris distribution in the gap is proposed as well.. The result of
calculations successfully displays the debris status with various types
of jet flushing, showing the superiority of the sweeping jet method.
|
|
Analysis and adaptive control of EDM sinking process using the ignition delay time and fall time as parameter
|
|
M. Weck (1), J.M. Dehmer
|
|
STC E, 41/1/1992, P.243
|
|
Keywords: EDM, Adaptive Control, Metal Removal, Electrodes |
Abstract : EDM sinking experiments were carried out to determine the pulse type
with the best ratio of material removal to electrode wear. The results
show, that the material removal is only dependent on the discharge
duration while the wear is caused only by undelayed and late ignition
discharges. This result and a process analysis using methods of the
chaos theory were the basis to develop an adaptive optimization of the
gap controller.
|
|
Laser microformation of thin film on glass substrate for repair of transparent defects on high density masks
|
|
T. Miyauchi, M. Hongo, K. Mitzukoshi, M. Okunaka, T. Kawanabe, Y. Koizumi / N. Taniguchi (1)
|
|
STC E, 41/1/1992, P.247
|
|
Keywords: Laser Beam Application, LSI, Defects, Baking |
Abstract : A new technique is developed for repairing transparent defects on high
density masks for VLSI. A thin Ag-Ta organometallic film is first
spin-coated onto a photomask and baked. Then an Ar laser microspot is
applied to a small area on this film. After rinsing the mask with a
solvent, an opaque layer remains at the laser-irradiated spot and the
rest of the organometallic material is washed away. The opaque film
formed locally by laser irradiation is dense enough to prevent light
transmission and durable enough to withstand repeated washing with
strong alkali and acid solutions.
|
|
Surface treatment by laser with high thermal gradients
|
|
G. Ricciardi (2), M. Cantello, C. Rivela
|
|
STC E, 41/1/1992, P.251
|
|
Keywords: Laser, Surface Treatment, Mathematical Model |
Abstract : A theoretical study of heat interact on of laser radiation has been
carried out. This study has supplied a mathematical adimensional model
able of describing the thermal field versus time depth in a very general
way. The model has been checked with experimental tests or, some ferrous
alloys by means of CO_2 laser. Specific tests using very high gradients,
got from model, have shows the formation of innovative metallurgical
structures.
|
STC F |
|
In situ ultrasonic measurement of the real contact area in bulk metal forming processes
|
|
M. Geiger (2), U. Engel, F. Vollertsen
|
|
STC F, 41/1/1992, P.255
|
|
Keywords: Forming, Friction, Interface, Contact Area, Ultrasonics |
Abstract : The real contact area (r.c.a.) between tool and workpiece is mainly
dependent on local forces and sliding velocities. It is one of the most
significant parameters describing the tribological state in forming
processes. An experimental technique is described which enables the
development of the real contact area to be measured in situ, ie during
the forming process. The ultrasonic method is proved to give signals of
great reproducibility and of high lateral resolution from which the
local values of r.c.a. can be determined by proper calibration. In the
first part of the paper a comprehensive view on the state of the art
investigating contact problems is given. In the second part the basic
principles of the ultrasonic method and its new application are
described. In the third and fourth part experimental results are given
showing the temporal and local distribution of the r.c.a in upsetting,
and further applications of this new technique are discussed, respectively.
|
|
Investigation of factors affecting the coefficient of friction and surface properties with a sheet drawing test
|
|
A. Azushima, M. Yamamiya / H. Kudo (1)
|
|
STC F, 41/1/1992, P.259
|
|
Keywords: Friction, Surface Properties, Lubrication, Sheet Metal, Drawing |
Abstract : The purposes of this study are to examine systematically the effect of
tribological factors on the coefficient of friction and surface features
of drawn sheet, and to propose a method fir predicting and controlling
the surface brightness before sheet drawing. Aluminum sheet drawing
experiments are carried out:, by changing the drawing speed and
viscosity of lubricant. From the experimental results it is seen that
since all the data fall on a single brightness versus calculated
entrance oil film thickness curve, the surface brightness however is
predictable using the entrance oil film thickness. The coefficient of
friction is not significantly dependent on the lubricant viscosity and
drawing speed.
|
|
Proposal of an evaluating method on lubrication
|
|
S. Isogawa, A. Kimura, Y. Tozawa (1)
|
|
STC F, 41/1/1992, P.263
|
|
Keywords: Forging, Lubrication, Evaluation |
Abstract : The tribological condition in forging is very severe due to no
subsequent supply of lubricant during forming, high contacting pressure
between tool and work piece and large surface extension of work piece. A
method to evaluate lubricants for forging, which is named spike forging
test is proposed in which a similar tribological condition as that in
forging is generated. In this test, a cylindrical specimen having a
height to diameter ratio of 1.2 is forged with a platen, of which
surface is provided with shallow concentric grooves, in an impression
die, of which approaching angle is 160°, containing a central tapered
cavity with 3°. An analytical simulation for this test shows that the
height of the spike formed in the central cavity when the platen reaches
to a certain distance from the die surface depends strongly an the
frictional resistance at the interface. The spike heights obtained by
experiment using several kinds of lubricants have a good correlation
with forging loads required and also ejecting loads after forging, and
hence these three values may be used for evaluating lubricants, The
results on lubrication obtained with the method proposed are in good
agreement with that in warm extruding operation of stainless steel can,
while the results of/ /the ring compression test don't agree with them.
|
|
Properties of cold worked metallic parts
|
|
P. Huml (2), M. Bergsing, M. Lindegren
|
|
STC F, 41/1/1992, P.267
|
|
Keywords: Forming, Mechanical Properties |
Abstract : The aim of the present paper is to present new results from
investigations of material behavior under forming conditions
corresponding to the strain path in forming processes characterized by
cyclic deformation mode and non proportional loading (cold pilger
rolling of tubes, swaging, draw-rolling in roller dies).
The influence of strain path on material behavior and final properties
has been simulated in uni-, two- and three-directional deformation
regimes. The obtained results explain the "unexpected" deformation
behavior and make it possible to predict properties of cold worked parts
with better accuracy than earlier.
|
|
Practical verification of ductile failure curves
|
|
W.H. Sillekens, J.H. Dautzenberg (2), S.M. Hoogenboom, J.A.G. Kals (1)
|
|
STC F, 41/1/1992, P.271
|
|
Keywords: Forming, Material Properties, DuctilityThis paper deals with |
Abstract : the ductility of workpiece materials in connection with forming. The
concept of the failure curve is used as a phenomenological means to
describe the ductility in dependence on the state of stress.
On the basis of analysis and experiment, two different forming
operations are studied in order to evaluate the practical relevance of
ductile failure curves. These processes are sheet bending and backward
can extrusion. As an illustrative material, recycled aluminum of
moderate ductility is used.
|
|
Computer aided design of dies to control dimensional quality of extruded shapes
|
|
R. Shivpuri, S. Momin / T. Altan (1)
|
|
STC F, 41/1/1992, P.275
|
|
Keywords: Computer, Die, Design, Quality, Extrusion |
Abstract : Conventionally, steel shapes are extruded using flat faced shear dies
resulting in flow related defects such as curvature and twist. As a
result, post-extrusion, straightening and detwisting are needed to
obtain acceptable dimensional quality of the product. This paper
presents a computer aided design and flow simulation procedure for
predicting these geometric defects and reducing them by the modification
of the die geometry including entry angles and the die land. This
procedure was applied to the extrusion of L-shaped structural shapes and
the results verified by controlled experiments on a 17,8 MN extrusion
press. Significant improvement, in product quality were achieved. This
design for manufacturing approach can be applied to other three
dimensional steady state processes such as shape rolling.
|
|
Friction-assisted extrusion of thin strips of aluminium composite material from powder metals
|
|
T. Nakamura, S. Tanaka, M. Hiraiwa, H. Imaizumi, Y. Tomizawa / K. Osakada (1)
|
|
STC F, 41/1/1992, P.281
|
|
Keywords: Extrusion, Friction, Thin-Strip, Aluminium Composite, Powder Metal |
Abstract : A new process of friction-assisted extrusion for producing thin strips
was developed. An aluminum foil of about 50mm in thickness could be
formed at an extrusion ratio R=200 with a considerably low pressure
ration p/2k=1 (p: punch pressure, k: yield shear stress) at room
temperature. The extrusion process is applied to powder forming for
producing thin strips of aluminum composite materials. Composite
aluminum powder miwed with SiC ceramics powder by 0~20 vol%37; is
successfully extruded into thin strips at room temperature.
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Shape control in CNC rotary swaging machine
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K. Osakada (1), Y. Goto, M. Shiraishi, T. Okada
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STC F, 41/1/1992, P.285
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Keywords: Metal Working, Swaging, Finite Element Method |
Abstract : To obtain sound products with good shape accuracy in the computer
controlled rotary swaging machine, the effects of working conditions and
the methods for improving the accuracy after forming process are
investigated by experiment and FEM analysis. The rigid-plastic FEM
analysis with an assumption of generalized plane strain can be employed
for predicting the shape of products. Optimum incremental angle of
billet rotation is found to be about 10 degrees when 4 dies are used. It
is clarified that slow retreat of dies and finishing blows after forming
are effective to suppress the shape distortion.
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Mathematical simulation of clad sheet rolling and sandwich sheet rolling
|
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M. Kiuchi (2), K. Shintani, Y.M. Hwang
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STC F, 41/1/1992, P.289
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|
Keywords: Asymmetrical Rolling, Clad heet Rolling, Sandwich Sheet Rolling, Numerical Simulation, Upper Bound Theorem, Sheet Bonding |
Abstract : Mathematical models and simulation techniques for clad sheet rolling and
sandwich sheet rolling are developed. They are based on the extended
upper bound/ /theorem. A series of numerical simulations of clad and
sandwich sheet rolling processes are performed. Through simulations, the
flow and deformation feature of each sheet (layer) at roll gap,
thickness ratio of each layer in rolled clad or sandwich sheet, rolling
force, rolling torque and longitudinal curvature of rolled product are
successfully calculated. The calculated results are compared with the
experimental measurements and very good agreements between them are
found. It becomes clear that the proposed simulation techniques are
useful enough for characterizing the clad sheet rolling and/ /the
sandwich sheet rolling. They enable us to obtain systematic knowledge
for designing desirable rolling schedule and performing stable operation.
|
|
Influence of hydrostatic pressure in cold pressure welding
|
|
W. Zhang, N. Bay (2)
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STC F, 41/1/1992, P.293
|
|
Keywords: Pressure Welding (cold), Hydrostatic Pressure, Surface Properties |
Abstract : Earlier work by Bay has shown the introduction of brittle surface
coatings by electrochemical or chemical plating to be useful when roll
bonding Al-Al. The coating layers fracture during deformation and
decover virgin surfaces which extrude through the cracks and establish
contact and metallic bonding to the adjacent surface. This paper
presents a systematic study of the influence of hydrostatic pressure on
the fracture of various types of surface layers. By cold pressure
welding Al-Al, Cu-Cu, AI-alloy-Al-alloy and Fe-Fe in simple upsetting
the ductility of different coatings have been studied at four different
levels of hydrostatic pressure. The ductility of electrochemical matt Ni
is very pressure sensitive, chemical Ni is somewhat less sensitive
whereas hard chromium is almost brittle even at large pressures.
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Temperature, heat flux and conductivity in bar rolling
|
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J. Jeswiet (2), S. Zou
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STC F, 41/1/1992, P.299
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|
Keywords: Rolling, Temperature, Heat Flux, Conductance |
Abstract : The temperatures in the roll gap in unlubricated cold rolling of
aluminum have been measured using a recently designed multipoint
temperature sensor. The sensor can measure the billet surface
temperature, the roll surface temperature and the internal roll
temperature simultaneously. The heat flux and interface thermal
conductivity are calculated from the interface temperatures by inverse
heat transfer methods. Tests were conducted at two rolling speeds and
the influence of speed can be seen. Experimental temperature results,
interface heat flux and thermal conductivity are shown for different
reductions and at different speeds.
|
|
Three-dimensional elastic-plastic FEM analysis on torsion of square-section bars
|
|
N. Hatada, K. Ueno, M. Ueda, S. Watanabe / N. Kinoshita (1)
|
|
STC F, 41/1/1992, P.303
|
|
Keywords: Forming, Torsion, Finite Element Method |
Abstract : This paper deals with FEM analysis on the torsion of solid bars. Using
FEM program MARC, three-dimensional elastic-plastic torsion problem,
which have not to date been solved, were analyzed. Thus, the
longitudinal strain during twisting is calculated for the first time.
The decreasing ratio of axial length becomes smaller with the increase
of strain hardening ratio. Furthermore, the decreasing ratio of axial
length of the square-section bar was larger than that of the
circular-section bar. The same tendency has been observed in precious
experiments.
|
|
An experimental study of heat transfer in metal forming processes
|
|
J.G. Lenard (1), M.E. Davies
|
|
STC F, 41/1/1992, P.307
|
|
Keywords: Metal Working, Heat Transfer |
Abstract : The success of predictive modeling of hot forming processes is
critically dependent on the correct description of the boundary
conditions of the deformation none. As far as the thermal events are
concerned, these are most conveniently described in terms of the heat
transfer coefficient. The magnitude of that coefficient has been shown
to depend on process and material parameters in addition to the presence
or absence of scaling and lubrication. The study will critically examine
the methods available to measure the coefficient of heat transfer:
discuss its effect or, predictive modeling and present experimental
results concerning its magnitude in compression and hot rolling.
|
|
Pressure control in hydraulic tube forming
|
|
D. Schmoeckel (1), C. Hessler, B. Engel
|
|
STC F, 41/1/1992, P.311
|
|
Keywords: Tubes, Hydrostatic Pressure, Pressure Control |
Abstract : At THD/PtU a manufacturing technique was developed in order to form
tubes under internal hydraulic pressure and axial force. The forming of
the bulging tube can be influenced by pressure control. Algorithms can
be developed to define pressure depending on the axial force or
parameters to that, such as displacement and time.
The most important parameters of geometry and load are recorded during
the process.
|
|
Materials processing issue related to fabrication of high Tc superconductor wire
|
|
S.K. Samanta (2), S. Samajdai
|
|
STC F, 41/1/1992, P.315
|
|
Keywords: Formability, Thermomechanical processing, Microcomposite |
Abstract : An understanding of the mechanism of thermomechanical processing of /Y
Ba_2 // Cu_3 O//_7-6 / /- Ag /superconducting microcomposite is needed
from the viewpoint of fabrication processing as well as improvement of
superconducting properties of the high /T_s /. materials. The processing
technique to obtain mechanically strong and environmentally stable /Y
Ba_2 // Cu_3 O//_7-6 / /- Ag /superconducting microcomposite wires is
discussed. It is shown that compositional changes do occur near the
interface. The effect of addition of small quantities of /Cu_2 O /and
/CuO /on/ /the superconducting properties and microstructure is
evaluated by electrical measurements and scanning and transmission
electron microscopy. These additions play a positive role in the
reduction of the width of the compositional variation zone. The results
are discussed from the point of view of thermodynamic and kinetic
aspects of oxygen diffusion and tetragonal ® orthorhombic transformations.
|
|
Effect of rigidity of die and press on blanking accuracy of electronic machine parts
|
|
T. Jimma, F. Sekine / Y. Tozawa (1)
|
|
STC F, 41/1/1992, P.319
|
|
Keywords: Blanking, Die-sets, Precision, Press |
Abstract : Blanking accuracy is decided by the relative displacement of an upper
die to a lower die in the blanking. Deformation of a die-set subjected
to an eccentric load in a press is analyzed, and the banding moment M
and the lateral force Q acting on the end of each guide post are
expressed by the inclination q and the lateral displacement DX of the
upper die. In the experiment, a die-set of sub-guide construction is
installed on a 1250 kN straight side frame press and 1100 kN C-type
frame press, and q and DX are measured under static loading and dynamic
loading of 100 spm. The calculated M and Q using the measure q and DX
show that the M and Q acting on the guide post ens are smaller on the
straight side frame press that on the C-type frame press though the
capacities of both presses are almost the same; The analytical method
proposed in this paper can be used in the selection of a press suitable
to a given die set and a given eccentric load.
|
|
Sensors and diagnostic systems in forming machines
|
|
E. Doege (1), K.H. Schomaker, T. Brendel
|
|
STC F, 41/1/1992, P.323
|
|
Keywords: Forming, Blanking, Deep-Drawing, Sensors, Process Monitoring, Optical Measurement |
Abstract : New optical sensors and standard sensors `or the measurement of tool
accuracy, acceleration, force and distance get more important for
process automation in forming machines. Together with a diagnostic
system based on a process control computer it is possible to analyze the
production system in regard to workpiece quality, process, machine and
tool. Examples of a diagnostic system for monitoring a high speed
blanking press with optoelectronic sensors and a diagnostic system for
monitoring the machine process in deep drawing are represented.
|
|
Forming of glass fiber fabrics into complex shapes-experimental and computational aspects
|
|
P. Boisse, J.C. Gélin (1), H. Sabhi
|
|
STC F, 41/1/1992, P.327
|
|
Keywords: Forming, Glass, Fibers, Finite Elements |
Abstract : The flow of resin during the RTM process mainly depends on the
properties of the glass fiber preform obtained by drawing. The paper
describes constitutive equations for glass fiber fabrics and their
application in a 3-D shell finite element program for the simulation of
complex shaping processes. The material model proposed is based on the
non-linear elastic response of a single fiber and is extended to
consider interactions between fibers. The finite element approach lies
on 3-D shell elements using a membrane assumption where the strains
along each fiber direction are calculated and used in a minimum energy
procedure. Experimental results concerning the forming of hemispherical
shapes reveal the importance of the shearing effects.
|
|
3-D Plotting of finite element sheet metal forming simulation results by laser stereolithography
|
|
T. Nakagawa (1), A. Makinouchi
|
|
STC F, 41/1/1992, P.331
|
|
Keywords: Finite Element Method, Sheet Metal, Forming, Stereolithography |
Abstract : 3-D Finite Element simulation is becoming one of the important and
powerful means to solve the various technical problems encountered in
the metal forming operations. But any suitable method to express the 3-D
simulation results has not been existed except the computer graphics on
CRT display. This paper deals with the new expressing method of 3-D
simulation results by using the laser stereolithography which is a kind
of 3-D plotter. Two types of sheet metal forming simulation results were
converted to solid 3-D shapes and it was confirmed that simulation
results were more easily understood and could be used more effectively
to solve the technical problems with the aids of laser stereolithography.
|
STC G |
|
New grinding methods for aspheric mirrors with large curvature radii
|
|
Z. Zhong / T. Nakagawa (1)
|
|
STC G, 41/1/1992, P.335
|
|
Keywords: Grinding, Aspheric Mirror, Large Curvature Radius, Shape Accuracy, Surface Roughness |
Abstract : In this paper some new methods for grinding toroidal mirrors, elliptic
and circular cylinder mirrors with large curvature radii are
investigated. By using the grinding methods proposed here, we
successfully obtain aspheric mirrors made of SiC, with higher precision
in shape accuracy and low surface roughness, as R_max = 20 - 40 nm, R_a
= 2 ~ 5 nm. The data measured show that the roughness is independent of
the direction of measurement. Also, the time consumed in the processes
is very short.
|
|
Development of a new mechanochemical polishing method with a polishing film for ceramic round bars
|
|
K. Suzuki, T. Uematsu, H. Ohashi, K. Kitajima, T. Suga, O. Imanaka / A. Kobayashi (1)
|
|
STC G, 41/1/1992, P.339
|
|
Keywords: Mechanochemical Polishing, Polishing Film, Ceramic Round Bar, Silicon Nitride |
Abstract : A new mechanochemical polishing method applicable to structural ceramic
round bars has been developed by using a polishing film method. A
silicon nitride round bar having 20 mm diameter was successfully
polished with a Cr_2 O_3 polishing film with 51 mm width. Surface
roughness of the bar was improved from 1.2 mm R_max to 45 nm R_max by
polishing it for 60 minutes and from 0.63 mm R_max to 24 nm R_max for 30
minutes. It was found the higher polishing speed, higjer oscillation
frequency of the film and I harder urethane contacting roller give
higher polishing efficiency and better surface roughness.
|
|
Magnetic fluid grinding cell design
|
|
T.H.C. Childs (2), H.J. Yoon
|
|
STC G, 41/1/1992, P.343
|
|
Keywords: Ceramics, Polishing, Ferromagnetic Materials |
Abstract : Magnetic fluid grinding is a process for the rapid grinding and
polishing of ceramic ball bearings. Grinding grits are levitated in a
ferrofluid contained above a bed of permanent magnets; and balls to he
finished are driven through this medium by a shaft against which they
are loaded, also by magnetic forces. This paper describes a theoretical
and experimental study of the magnetic forces which exist in the process
and discusses design of the magnetic fluid grinding cell in terms of
these. Shaft contact loads of the order of Newtons per ball are
achievable and grits may be levitated tens of mm above the magnet bed.
|
|
Surface structure of Mn-Zn ferrite single crystals ground by an ultra-precision surface grinder with various diamond wheels
|
|
T. Namba, Y. Yamada, A. Tsuboi, K. Unno, H. Nakao / I. Inasaki (1)
|
|
STC G, 41/1/1992, P.347
|
|
Keywords: Ultra-Precision Machining, Diamond Wheels, Surfaces |
Abstract : Manganese-zinc ferrite single crystals have been around by the
ultra-precision surface grinder having a glass-ceramic spindle of
extremely-low thermal expansion with various resinoid-bonded diamond
wheels of #200-#3000. The ground surface can be classified into three
categories, that is, fracture mode, ductile mode and ductile & fracture
mode grinding by observing, the surface with a Nomarski interference
microscope. There is no micro crack under the surface ground in the
ductile mode, The relationship between the surface roughness and
grinding conditions has been also clarified. The micro-.surface
structure has been also discussed with an STM and AFM measurement.
|
|
A neural network approach to the decision making process for grinding operations
|
|
M. Sakakura, I. Inasaki (1)
|
|
STC G, 41/1/1992, P.353
|
|
Keywords: Grinding, Dressing, Surface Roughness |
Abstract : In this paper, a decision making process model for grinding operations
is proposed. It has a multistage structure and consists of different two
types of neural network: the Feed-Forward network and the
Brain-State-in-a-Box network. As an application example of the model,
the relationship between the dressing conditions and the surface
roughness of ground components is simulated. The results indicate that
the proposed model is capable of learning the stochastic data of surface
roughness and recalling the dressing conditions which attains the
required surface roughness. The simulated process can he considered to
be quite similar to the decision making process of experienced operators.
|
|
Enumeration of microorganisms in metalworking fluids using photometric methods
|
|
R.W. Coughlin, D. Williams, E. Seveau, R. Veith, T.D. Howes (2)
|
|
STC G, 41/1/1992, P.357
|
|
Keywords: Grinding Fluids, Contaminations, Measurements |
Abstract : This paper will discuss two approaches to assaying concentrations of
microorganisms in metalworking fluids using light. One approach employs
fluorescent dye to stain the DNA within microbial cells suspended in the
fluid. The intensity of light emitted by the bound dye is measured to
provide an estimate of microbial concentrations. The second approach is
based upon a light-producing reaction of ATP, a measure of the energetic
state that is essentially constant for all living cells. The rate of
light production is proportional to the concentration of ATP arid,
therefore, to the concentration of microbial cells; the light emitted is
then a measure of the number of cells in a sample of fluid. Both
approaches provide reproducible and reliable results. These methods have
the potential of providing rapid, on-site measurement of microbial loads
and are being explored as alternatives to standard piste count and dip
slide methods that require an incubation period of up to two days to
achieve results.
|
|
Sensitivity analysis and tolerance allocation for micro-planer dill point grinders
|
|
K.F. Ehmann (2), S.K. Kang, C. Lin
|
|
STC G, 41/1/1992, P.361
|
|
Keywords: Grinding, Drill Points, Tolerances |
Abstract : A sensitivity analysis and tolerance analysis/allocation of the grinding
parameters is presented to guide the design of planar micro-drill point
grinders. The mapping from the desired micro-planar drill point geometry
parameter space to he grinding parameter space of the drill grinder has
been established to determine a unique grinding parameter set for the
desired planar micro-drill point geometry. By means of the sensitivity
analysis (variations of the drill point geometry parameters with respect
to the grinding parameters), it is indicated which parameters are the
most important and most profoundly affect drill point geometry. To
specify the upper and/or lower limits of grinding parameter tolerances,
and to assure that the total tolerance of the drill point geometry is
maintained throughout the desired range, two methods are presented.
Tolerance analysis shows he maximal tolerances of the drill point
geometry parameters in terms of the maximal tolerances of the grinding
parameters. This method requires the tuning of .he tolerances of the
grinding parameters until the tolerance of point geometry are satisfied.
As an inverse problem to tolerance analysis, a rational tolerance
allocation algorithm is investigated to assign the unknown grinding
parameter tolerances from the known maximal allowable tolerances of the
drill point geometry.
|
|
Study on mechanism of ceramics grinding
|
|
K. Kitajima, G.Q. Cai, N. Kumagai, Y. Tanaka, H.W. Zheng (1)
|
|
STC G, 41/1/1992, P.367
|
|
Keywords: Ceramics, Grindability |
Abstract : The grindabilities of ceramic materials are evaluated through the
measurement of the grinding forces, energy, temperature and wheel wear,
and the SEM examination of the ground surface arc the grinding swarf.
Comparing with SiC and Si_3 N_4 , the grinding force, energy,
temperature and the wheel wear in AI_2 0_3 grinding with the same
removal rate are lowest. The ground surface roughness of SiC is better
because no any bulge formed on the side edges of streaks. The
grindability of ceramics is related to the mechanical behaviors of
materials at grinding temperature.
|
|
Monitoring of grinding wheel wear
|
|
E. Brinksmeier (2)
|
|
STC G, 41/1/1992, P.373
|
|
Keywords: Cylindrical Grinding, Data Acquisition, Monitoring, Optical Measurement, Wear |
Abstract : A new optical sensor has been developed in order to monitor the cutting
capacity of grinding wheels. This sensor is based on the principle of
triangulation. For the investigation oft he grinding wheel topography
even during the grinding process the sensor has been mounted at the
opposite side of the working area of an external grinding machine. The
output signals of the sensor are processed by a digital data acquisition
/system /controlling the position of the sensor and calculating
different parameters to describe the state of wheel wear. These
parameters take various aspects of macroscopic and microscopic wheel
wear into consideration. Some results which have been obtained using a
corundum grinding wheel are presented. These results were achieved
during the rotation of the wheel at cutting speed.
|
|
Surface topography assessment of high-precision coated abrasive tape and estimation of its machining performance
|
|
K. Yanagi, Y. Tsukada, R. Yamada / H. Yoshikawa (1)
|
|
STC G, 41/1/1992, P.377
|
|
Keywords: Abrasives, Roughness, Texture |
Abstract : A topography assessment of coated abrasive tape was dealt with for
distinguishing its functional performance. The three-dimensional
distribution of projecting abrasive grains en a tape surface was
presented and the related geometrical parameters for classifying the
coated abrasive tapes were proposed. A comparison vas made between those
parameters of the tape surface and the generated surface textures on the
aluminum alloy substrate for magnetic/ /rigid disks. The topographical
parameters of textured substrate surface which are based on the profile
amplitude. microgeometry near the valley bottoms and their number were
correlated fairly well with the spatial distribution of the effective
coated abrasive grains in conjunction with working fluid or coolant.
|
|
On surface modification of superabrasive grits by CVD of chromium
|
|
A.K. Chattopadhyay, H.E. Hintermann (1)
|
|
STC G, 41/1/1992, P.381
|
|
Keywords: Diamond, CBN, Surface Modification, CVD of chromium |
Abstract : In the present work, an attempt has been made to modify the surface of
diamond and CBN grits in order to enhance their adhesion with the metal
matrix. Chromium CVD process was used for this purpose. SEM and EP-NIA
studies have shown that the type of chemical reagents, deposition time,
deposition temperature and the type of abrasive grit substrate could
influence the morphology and composition of the film deposited. Such
surface modification was found to be more effective for diamond than for
CBN in improving wettability and bondability of the Ni-based matrix.
This was confirmed by improved retentivity of the diamond grits in the
Ni-based matrix during simulated grinding test.
|
|
The real contact length between grinding wheel and workpiece : a new concept and a new measuring method
|
|
Z.X. Zhou, C.A. Van Luttervelt (1)
|
|
STC G, 41/1/1992, P.387
|
|
Keywords: Grinding Process, Maximum, Local and Real Contact Length, Contact Length Measurement, Grinding Zone |
Abstract : Research on the contact length in grinding is needed to understand the
grinding mechanism and for analysis of grinding operations. In this
paper, a new concept for the grinding contact length is proposed. The
contact length is distinctly divided into a maximum contact length and a
local contact length. A new measuring method for both contact lengths,
called the Applied Power Source or APS method, is presented. The results
obtained show that the maximum contact length is about 22-50%37; longer
than the local one. Awareness of the variation of the local contact
length along the width of the contact zone results in a better
understanding of the contact phenomenon between wheel and workpiece.
|
|
Galileo principe
|
|
M.C. Shaw (1)
|
|
STC G, 41/1/1992, P.393
|
|
Keywords: Grinding, Tmperature, Analysis, Heat Transfer, History |
Abstract : In his second book "Dialog concerning two new sciences" published in
1638, Galileo made an amazing assumption that violates something as
fundamental as static equilibrium. Yet, in applying this to many
problems, he obtained correct answers. The reason is that he sought
relative answers rather than absolute ones and the errors involved
cancelled out. This is a useful analytical tool for engineering analysis
which I call the dimensional analysis to the complex problem of
estimating fine grinding temperatures in order to simplify the analysis
and end result.
|
STC M |
|
An automated planning, control and inspection system for robotic deburring
|
|
M.A. Elbestawi (2), G.M. Bone, P.W. Tam
|
|
STC M, 41/1/1992, P.397
|
|
Keywords: Robots, Deburring, Adaptive Control |
Abstract : This paper describes a system for the automated planning, control and
inspection of robotic edge deburring. The task planner uses an object
oriented distributed artificial intelligence approach along with
computer-aided design models to plan a collision-free path. The path is
adjusted online to maintain the desired chamfer depth of cut using a
high-bandwidth active end effector. The control system incorporates: a)
sensor fusion of force and vision data, b) parameter adaptive predictive
control, and c) learning control. Task completion is verified through
in-process inspection of the chamfered edges. Simulation as well as
experimental results are presented.
|
|
Adaptive control of a modular robot system
|
|
P.C. Mulders (2), R.J. Voorkamp, J. Jansen, A.C.H. Van Der Wolf (1)
|
|
STC M, 41/1/1992, P.403
|
|
Keywords: Robots, Adaptive Control |
Abstract : Adaptive control is a process of modifying one or more parameters of the
controller and these adaptive control algorithms are specially important
for flexible manipulators with place and time dependent parameters,
varying during trajectory performance.
Here an adaptive controller is described as a combination of the
computed torque method and an adaptive PD controller based on the Model
Reference Adaptive Control (MRAC) method.
It has been applied to a modular robot for loads up to 50kg consisting
of a linear and a rotary actuator sowing these parameters variations.
Necessary models, extended and reduced, of this modular robot have been
made and the proposed controller has been tested in simulations and in
the real configuration also with respect to stability, convergency and
robustness.
|
|
Neural network control of robots
|
|
M. Shoham, C.J. Li, Y. Hacham, E. Kreindler / R. Weill (1)
|
|
STC M, 41/1/1992, P.407
|
|
Keywords: Robots, Control, Neural Network |
Abstract : The abilities of/ /massive computation parallelism and self-learning
make the neural networks a promising candidate for intelligent robot
control. In this investigation, a robot controller consisting of inverse
kinematics and inverse dynamics algorithms, has been replaced by two
neural networks. A different approach to the neural networks learning
phase made this solution applicable for robots control from the point of
view of learning time as well as accuracy. First, the learning algorithm
has been changed from the traditional back-propagation method to the
quasi-Newton method. Secondly, the initial neural network weights which
usually are chosen arbitrarily, have been determined in a systematic way
based on a geometric interpretation of the neuron function. Simulation
results show the significant improvement of both learning time and
accuracy, which practically enables the use of a neural network
controller in robotic applications.
|
|
Research on the efficiency of feed forward controllers in M
|
|
G. Pritschow (1), W. Philipp
|
|
STC M, 41/1/1992, P.411
|
|
Keywords: Position Controller, Path Errors, Feedforward Control, Predictive Control, Uncertain Parameters, Direct Drives, Path Accuracy |
Abstract : The path accuracy of machine tools and industrial robots is influenced
by the characteristics of the control loops of all axes that are
involved in the course of the path. In comparison to classical
electromechanical drives, direct drives allow considerably higher
accuracies and velocities. The control error can be reduced further by
additional feed-forward controls. In he course of this paper,
feed-forwards control procedures developed at our institute at the
University of Stuttgart are presented and compared to known procedures
for the use in direct drives. This comparison mainly concentrates on the
influence of parameter uncertainties and the resulting path behavior.
|
|
Automatic design of tuning parameters for predictive control of CNC machines
|
|
P. Boucher (2), D. Dumur (2), S. Daumüller
|
|
STC M, 41/1/1992, P.417
|
|
Keywords: CNC,Control System, Machine Tool |
Abstract : Predictive control laws nowadays appear to be successfully implemented
on many French and German C.N.C. machines and ensure sufficient
performances in term of rapidity, disturbance and errors cancellations.
But even if the control law remains very simple, there is up to now no
method that provides the best set of tuning parameters it a systematic
way and without any help.
We propose in this paper an original and automatic design of these
parameters, giving at the end the best tuning in Term of robustness and
stability of the predictive control law. With this method based on
simple frequential considerations, and even if the user has no
particular knowledge about predictive control, the result for the C.N.C.
machine is a robust and stable control algorithm corresponding to the
desired performances. Experimental results prove the validity and
usefulness of this new approach.
|
|
Ultra-precise machine tool equipped with a giant magnetostriction actuator
|
|
H. Eda, E. Ohmura, M. Sahashi, T. Kobayashi / N. Ikawa (1)
|
|
STC M, 41/1/1992, P.421
|
|
Keywords: Ultra-Precision Machining, Actuators, Diamond Turning Machines, Brittle-Ductile Transition, Giant Magnetostriction |
Abstract : By developing several alloys with the composition Tb_x Dy_1-x (Fe_y
Mn_1-y )_n , a giant magnetostriction actuator was manufactured. The
output power of them is several times and the displacement is several
ten times as much as PZT without a magnifier. A temperature controller
to keep a fluctuation of the cooling water within 10m°C was developed
for the actuator. An ultra-precise machine tool was also developed,
equipping the present actuator. The depth of cut can be set with the
accuracy of several nanometers by the actuator and cut by a turning
diamond tool. The hard and brittle materials such as glass and ceramics
were finished in ductile mode, and the surface roughness was obtained
within several nanometers.
|
|
Structural configuration and performances of machining environment-controlled ultra-precision diamond turning machine "Capsule"
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H. Shinno, H. Hashizume, Y. Ito (2), C. Sato
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STC M, 41/1/1992, P.425
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Keywords: Ultra-Precision, Machine Tools, Diamond Turning Machine |
Abstract : To establish a future ultra-precision machining technology of nano-meter
order, it is important to realize the machine tool structure based on a
new design concept. Therefore, a Machining Environment-Controlled
Ultra-Precision Diamond Turning Machine has been newly developed. This
machine can be characterized by capsule-like closed structure along
with various new mechanisms. The machine aims especially at the
manufacture of the high precision mirror under various environments. At
present, the flat mirror with 3 nm in surface roughness (Al-alloy) is in
reality/.
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Instrumented milling cutter for in-process measurement of spindle error motion
|
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S.A. Spiewak (2)
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STC M, 41/1/1992, P.429
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Keywords: Sensors, Spindles, Errors |
Abstract : An instrumented cutter developed for a new generation of machining
centers designed specifically for die making in the car industry is
presented. A three-component accelerometer installed inside of the
cutter facilitates the measurement of spindle error motion exactly at
the cutter location. The method of signal conversion from accelerations
measured by the rotating sensor into the spindle displacements in the
machine tool reference system is outlined. A setup used in the
laboratory tests and representative results are presented.
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Stabilizing chatter by automatic spindle speed regulation
|
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S. Smith, J. Tlusty (1)
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STC M, 41/1/1992, P.433
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|
Keywords: Milling, Chatter |
Abstract : This paper describes the theoretical basis behind a system for the
elimination of chatter in, milling through the automatic regulation of
the spindle seed. This technique is most effective in milling operations
where the tooth passing frequency can approach the natural frequency of
the mode responsible or chatter. Examples detailing the convergence
process are presented, and non-convergence situations are described.
Experimental data are quoted to illustrate typical improvements in metal
removal rate. The various modes of operation of the system are described.
|
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Automated rapid prototyping utilizing laser scanning and free form machining
|
|
C. Bradley, G.W. Vickers / J. Tlusty (1)
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STC M, 41/1/1992, P.437
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|
Keywords: Laser Scanners, CNC Machining, Multiple Surface Patches, Free-Form Surfaces, Quadric Surfaces |
Abstract : The paper deals with the use of a laser based method for rapid
prototyping of free-form and quadric surface multiple patch models.
Integration of a triangulation based laser scanner with a CNC machining
center is discussed. Methods of analysis of the mass of irregular and
unformatted positional data generated by the scanner are presented in
order for a series of basic quadric and compound curved surfaces to be
defined. The procedure for defining the CNC cutter path for a
generalized shaped end-milling cutter is given with illustration of the
applicability of the method to a variety of test objects. The work is a
new approach utilizing laser scanned data for direct machining of
quadric and free-form surfaces.
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|
Collaborative coordination control (CCC) of distributed multi-machine manufacturing
|
|
S.Y. Nof / R. Weill (1)
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STC M, 41/1/1992, P.441
|
|
Keywords: Optimization, Distributed Control, Flexibility, Coordination |
Abstract : Coordination control of multi-machine workstations in distributed FMS
and other manufacturing facilities has been designed with synchronous
and asynchronous techniques. In a recent study at Purdue, the element of
machine collaboration has been added to the coordination control, to add
to the flexibility and reliability properties of the processes. The new
Collaborative Coordination Control strategy is explained and illustrated
with two specific implementation case studies based on one U.S. and one
French FMS facility. Impacts on performance measures are evaluated.
Certain advantages, limitations and open questions of the approach are
discussed.
|
|
Precision turning by means of a simplified predictive function of machining error
|
|
T. Asao, Y. Mizugaki, M. Sakamoto / H. Sato (1)
|
|
STC M, 41/1/1992, P.447
|
|
Keywords: Turning, Errors, Compensation |
Abstract : This study deals with a compensative system for machining errors in
turnings by adopting a simplified predictive function and modifying
previous NC commands. The predictive function is represented in .he form
of an exponential function as an experimental expression and installed
into an auto NC programming tool as a database. A NC command is modified
by varying its depth of cut from which the notion resolution of a lathe
subtracted everywhere the predicted machining error exceeds the motion
resolution. The experimental results support the efficiency of the
compensative system proposed in some intermittent metal cutting.
|
|
Investigation into temperature dependence of motor current measurements applied to monitoring and adaptive control
|
|
M.A. Mannan (2), S. Broms
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|
STC M, 41/1/1992, P.451
|
|
Keywords: Adaptive Control, Temperatures, Tool Wear |
Abstract : It is a crucial requirement, when using motor-current-based sensing
systems, that the ratio between cutting forces and the corresponding
motor currents is constant during the period of observation. Different
induction motors employed in spindle and teed drives have been shown to
have different sensitivities to heating cycles, depending upon their
design and the magnetic materials used in them. Besides the changes in
electro-magnetic losses due to temperature variations, changes in
mechanical losses in different components incorporated in machine tool
drives are the major contributory factors. We have experimentally
studied the effect of the above-mentioned factors on the accuracy of
motor current measurements, taking into account variations in temperature.
|
|
A new approach to modelling thermal behaviour of machine tool under service conditions
|
|
J. Jedrzejewski (1), W. Modrzycki
|
|
STC M, 41/1/1992, P.455
|
|
Keywords: Machine Tool, Modelling, Thermodynamic Properties |
Abstract : The paper presents a new method of modeling thermal behavior of a
machine tool in service based on integrated determination of power
losses in the kinematic system components, temperature and thermal
displacement. The method is applicable to any operational conditions.
The mathematical model and its organization are presented. Basic
features of the method are shown in a case of a machining center whose
services thermal behavior is analyzed.
|
|
Influencies on the availability of FMS
|
|
U. Heisel, H. Hammer / G. Pritschow (1)
|
|
STC M, 41/1/1992, P.459
|
|
Keywords: Availabitily, FMS |
Abstract : A major prerequisite for the economical operation of Flexible
Manufacturing Systems is a high level a availability. This is
determined, on the one hand, by technical factors and, on the other
hand, by limitations in the corporate organization and personnel. The
paper presents results of a field study in which reasons for breakdowns
caused by technical errors and inadequate organization are viewed in
relation to the effects of insufficient qualification and motivation of
personnel.
|
|
Processintegrated measurements for quality control with turning
|
|
H. Trumpold (1), R. Mack
|
|
STC M, 41/1/1992, P.463
|
|
Keywords: Processquality, Sensorsystem, Turning, Force Measurement, Monitoring |
Abstract : The paper deals with a process integrated piezoelectric force sensor
system working in a frequency range of 5 Hz...20 kHz. Together with the
software for the evaluation of the continuous dynamic signal the system
allows the determination of deviations from the normal teach-in function
of parameters typical for the process within one workpiece revolution or
within defined time intervals. The efficiency of the measuring and
quality monitoring strategy and the correlation between dynamic forces
and disturbances within the system machine-tool-work-fixture are
described. The investigations were made on one and multi-spindle lathes.
|
|
Optimization of design tolerances of servomechanisms
|
|
H.H.B. Roelofs, C.J. Heuvelman (1)
|
|
STC M, 41/1/1992, P.467
|
|
Keywords: Servomechanisms, Optimization, Tolerancing |
Abstract : A method is proposed to specify maximum tolerance ranges on nominal
values of system parameters of servomechanisms and the nominal values
themselves using semi-infinite optimization algorithms. The performance
specifications of the servomechanism are transcribed to semi-infinite
inequalities. The feasible design area is assumed to be convex. The
dynamic behavior of the servomechanism is represented by a linear state
space model.
|
STC O |
|
Approach to the identification and quantification of environmetal effects during product life
|
|
R. Züst, R. Wagner / B. Schumacher (1)
|
|
STC O, 41/1/1992, P.473
|
|
Keywords: Organization of Product Development, Cost Analysis, Environmental Impact, Product Life-Cycle, Ecological Balance, Extended Quantification |
Abstract : Rising environmental costs and their transfer to those who incur them
become serious hazards for the industrial enterprise. To avoid these
hazards special activities have to be adopted during the product
development phase. Quantifiable evaluations covering all phases of a
product's life are of great significance for product development. The
authors conclude that using existing ecological balances is not a
suitable method. Further quantification is necessary, which deals with
costs, material flows, energy flows, mixing of materials, hazards,
damage and ethical aspects.
|
|
A new system for automatic understanding engineering drawings
|
|
L.Y. Zhang, J.Y. Zhu (1), Q.Y. Zhu
|
|
STC O, 41/1/1992, P.477
|
|
Keywords: Computer Vision, Engineering Drawing, Automatic Understanding |
Abstract : A new system which can understand engineering drawings automatically and
convert the result data to CAD / CAM system is introduced in this paper.
Engineering drawings are inputted into a vision system via a CCD camera
as an image. First, algorithms for preprocessing the image to remove
noise, segment the image, and convert raster image to vectors are
presented. Then, contours are fitted to straight lines, arcs and
symbols in the drawings are recognized. Finally; after editing, the
result data is transformed to CAD CAM system to obtain machine program.
|
|
Design for manufacture : expert processing sequence selection for early product design
|
|
J. Farris, W.A. Knight (2)
|
|
STC O, 41/1/1992, P.481
|
|
Keywords: Design for Manufacture, Process Selection, Material Selection |
Abstract : A method to systematically map part geometry and material requirements
onto sequences of processes and compatible materials is
described. The geometrical and material constraints of the design
are input information for the system. The system produces a list of
practical processing sequences and material combinations. The sequences
are ranked according to the difficulty of manufacturing the part with
particular processes selected and how well a material meets the material
requirements for the part.
|
|
Dynamic optimization of job distribution on machine tools using time decomposition into constant job-mix stages
|
|
L. Kops (1), S. Natarajan
|
|
STC O, 41/1/1992, P.485
|
|
Keywords: Production Scheduling, Job Allocation, Dynamic Optimization, Linear Programming |
Abstract : A new concept of time decomposition which allows to combine linear
programming and heuristics to solve the dynamic problem of job
distribution on machine tools for a scheduling horizon is presented. An
optimization algorithm based on this decomposition principle and which
considers also the setup time is described. The application of the
algorithm is demonstrated on a case of multiple-operation job processed
according to the arrival and due date schedule, on machine tool grouped
in sections according to operations. The results indicate that the
optimization based on the concept of time decomposition into constant
job-mix stages, CMS, leads to increased utilization of machine tools,
higher production rate in sections, with shorter makespan of individual
jobs and reduced computational time.
|
|
A CAPP system for non-linear process plans
|
|
J.P. Kruth (2), J. Detand
|
|
STC O, 41/1/1992, P.489
|
|
Keywords: Computer Automated Process Planning (CAPP), Knowledge Based Systems, Petri Nets, Non-Linear Process Plans |
Abstract : Non-linear process plans are process plans which comprise different
manufacturing alternatives. Such non-linear process plans increase the
flexibility of scheduling activities, and allow to remedy quickly to
disturbances in the workshop. They are represented by Petri nets.
The automatic generation of a non-linear process plan is realized in
different steps
- the feature based workpiece description is transformed into a
non-linear sequence of operation steps
- the resources, capable to manufacture the specified operation steps,
are determined
- the non-linear sequence is converted into a non-linear process plan
which is directly usable for scheduling.
The developed CAPP system has been tested for hydraulic components.
|
|
Application of flows and envelopes to NC machining
|
|
D. Blackmore, M.C. Leu (2), K.K. Wang (1)
|
|
STC O, 41/1/1992, P.493
|
|
Keywords: Geometric Modeling, Numerical Control, Machining |
Abstract : The characterization and representation of swept volume has important
applications in NC machining theory and practice. Modern NC programs are
quite versatile: they provide programmers with the capacity of
performing a variety of possible types of motion for the cutting tool
such as linear, circular, helical, parabolic and cubic interpolation.
Using the method of sweep differential equations, techniques which
incorporate the method of envelopes are developed for constructing the
swept volume of simple tools which are generated by topical motions in
NC programs. The technique for linear, circular and helical motions is
shown to effectively reduce the dimension of the problem by two. For
completely general motions it is shown that the procedure can be best
effectuated by first imbedding the configuration in a space of one more
dimension. Several examples are included to illustrate the
implementation of the methods which are introduced.
|
|
Computer aided analysis and planning of set-up process
|
|
H.P. Wiendahl (1), Z. Fu
|
|
STC O, 41/1/1992, P.497
|
|
Keywords: Set-Up Process, Set-Up Structure, Analysis, Planning |
Abstract : To adapt the consequence of set-up time for the manufacturing process
and the enterprise success, it is necessary to consider systematically
the set-up process in the production. The paper shows a method, which
enables to analyze the set-up process and derive measures for set-up
time reduction upon the basis of ascertained weakness. The necessity of
the planning of the set-up process in analogy to manufacturing process
results from the existing problems in the set-up organization. A
prototype of such planning system has been developed to equip the set-up
personnel with aids, which make a structured and disturbance free set-up
process possible.
|
|
An intelligent sensor for robotics
|
|
D.T. Pham / A.W.J. Chisholm (1)
|
|
STC O, 41/1/1992, P.501
|
|
Keywords: Robotics, Sensors, Part Feeding |
Abstract : The paper describes a novel low-cost sensor based on the measurement of
inertia-sensitive parameters to detect the location of workpieces in
robotic assembly or pick-and-place applications. The sensor is a
vibrating system comprising a platform which holds the workpiece to be
located and a flexible column which supports the platform. The
inertia-sensitive parameters used are the natural frequencies of this
vibrating system. A transputer is employed to process the vibration
signals to obtain the exact coordinates of the workpiece relative to the
platform. The processing techniques described include Kalman filtering
and fuzzy interpolation.
|
|
Real-time machining state detection using multi-axis force sensing
|
|
M. Mitsuishi, T. Nagao (2), Y. Hatamura, S.I. Warisawa
|
|
STC O, 41/1/1992, P.505
|
|
Keywords: Real-Time Machining State Detection, Force Vector Locus, Intelligent Machining |
Abstract : To realize fully-automated, intelligent machining, it is necessary to
develop a method for judging the machining state in real-time. A method
for determining the machining state in milling is described. The
technique utilizes the ^" force vector locus" determined from the
measured force data. The variance in the distance from the center of
gravity to each sample point is used to distinguish between normal
cutting and chatter conditions. Because the variance depends on the
cutting conditions, as well as on the cutting state, the threshold
variance is set relative to the ideal variance calculated from the
Kronenberg cutting force model. Experiments have demonstrated the
utility of the technique in actual milling operations.
|
|
Robotic workcell cycle time optimization using computer graphics
|
|
R.G. Fenton (1), D. Poon, S.P. Davies
|
|
STC O, 41/1/1992, P.509
|
|
Keywords: Robot, Workcell, Cycle Time |
Abstract : The position of a robot within a flexible manufacturing workcell, where
machine station and storage locations are predetermined, plays an
important role in determining the cell's cycle time [1].
In this paper, the optimum position of the robot (defined as the
position of the robot in the workcell that results in the minimum cycle
time) in a multi-location industrial workcell is determined through the
use of a numerical optimization routine and ROBCAD, a kinematic computer
graphics simulation program.
|
|
Cutting conditions optimization in 3 axis NC milling
|
|
K.D. Bouzakis (2), R. Paraskevopoulou
|
|
STC O, 41/1/1992, P.513
|
|
Keywords: Milling, Process Simulation, Cutting Forces, Tool Wear, Cutting Conditions Optimization |
Abstract : For the optimization of the cutting speed and feed rate in 3-axis
NC-milling a computer supported procedure is presented. Input to that
procedure is the NC- code off a part. The tool motions, derived from the
NC-code, are grouped in subprocesses. Considering the manufacturing cost
and accuracy, using developed models, which enable the calculation of
the cutting force components and the tool wear, the optimum feedrate and
cutting speed values along the tool path are calculated. These optimum
cutting conditions are automatically implemented into the NC-code, which
is properly modified. An application example of the developed procedure
is presented.
|
|
An integrated cutting tool selection and operations sequencing method
|
|
H.M. Rho, A.H. Van't Erve, H.J.J. Kals (1)
|
|
STC O, 41/1/1992, P.517
|
|
Keywords: CAPP, Operation Sequencing, Tool Selection |
Abstract : Within the PART CAPP system, the selection of an optimum operation
sequence is related to the modules which perform the machining method
and cutting tool selection. This study analyzes the technical and
economical aspects of operation sequencing and presents a method which
is capable of generating an optimum solution on the basis of previously
selected machining operations and alternative cutting tools per
operation. Precedence relations between operations provided by the
method selector are used as constraints which should not be violated.
The operation sequencing method simultaneously assigns single tools from
a list of alternatives to each operation and manipulates the operation
sequence in order to minimize the total number of tool changes and the
number of required tools.
|
|
Building wider scope integrated manufacturing systems
|
|
R.H. Weston / B.J. Davies (1)
|
|
STC O, 41/1/1992, P.521
|
|
Keywords: Integrated Industrial System, Information Management System, Computer Integrated Manufacturing |
Abstract : The industrial use of an 'open' approach to building integrated
manufacturing systems is described and compared with conventional
turnkey and custom built solutions. The case study system developed by
the author integrates planning, supervision and change control
operations, along with information support and management functions. The
paper shows how the approach is applied to four in production surface
mount technology assembly lines. The benefits of the 'open' approach are
documented in terms of very significant savings in engineering cost and
time. Furthermore the paper illustrates how the extendibility of the
open approach can lead to enterprise-wide integration.
|
|
A generator for creating adaptive post processors
|
|
A. Blumfield, M. Shpitalni (1), E. Lenz (1)
|
|
STC O, 41/1/1992, P.527
|
|
Keywords: Adaptive Post Processor, CAD/CAM, CNC, Manufactuing Philosophy |
Abstract : The combination of modern CAD/CAM systems with CNC machines allows for
creation of adaptive post processors with significant advantages over
the classical post processors: (1) They generate g-code which reflects
the manufacturing philosophy of the individual user; (2) They use
technological tables for automatically obtaining various machining
parameters; (3) They make better use of the CNC programming options,
producing compact legible code with better manufacturing quality; and
(4) They can be modified on site during installation. A special
generator for creating such adaptive post processors has been developed
and is represented in this paper.
|
|
Fractal path generation for a metal-mold polishing robot system and its evaluation by the operability
|
|
Y. Mizugaki, M. Sakamoto / T. Sata (1)
|
|
STC O, 41/1/1992, P.531
|
|
Keywords: Mechatronics, Polishing, Robot Programming |
Abstract : This paper suggests a new method of Fractal path generation in a robot
system of polishing metal molds. It is conducted through the generation
of a planer Peano curve in the X-Y domain and its orthogonal projection
onto the free-form surface of a workpiece The orientation of the
end-effector along the path is set perpendicular to the surface. By
calculating the sum of operability of the robotic linkage along the
path, the path can be evaluated from the ease of the robots' motion. The
experiments inclusive of the polishing force control are illustrated and
a beef conclusion made.
|
|
CAD-CAI Integration for complex surfaces
|
|
D.V. Majstorovic, p. Bojanic, V. Milacic (1)
|
|
STC O, 41/1/1992, P.535
|
|
Keywords: CAD-CAI, Complex surfaces |
Abstract : The integration of systems in the field of engineering activities on the
basis of CA technology begins with the establishing of internal model of
a workpiece in CAD system. Feature-based modeling offers a number of
advantages over the classical geometrical modeling in the building of
integrated systems. This paper describes the architecture of CAD/CAI
(Computer Aided Design/Computer Aided Inspection) integrated system
based on the recognition of forms and artificial intelligence. As
specific forms in the model may also appear the forms with complex
surfaces. Initial result of the investigation justifies such an approach
in the integration of systems in the field of CA technologies.
|
|
Generation of 5-axis control collision-free tool path and post-processing for NC data
|
|
Y. Takeuchi (2), T. Watanabe
|
|
STC O, 41/1/1992, P.539
|
|
Keywords: Machining Center, Tool Path, Postprocessing |
Abstract : The study deals with the general method of generating NC data from
collision-free tool path of 5-axis control machining centers. The use of
5-axis control machining centers, capable of machining complicated
workpiece shapes efficiently and accurately, is recently increased.
Then, it is inevitable to generate collision-free CL data and NC data
rapidly. CL data are generated by the main-processor having the
collision avoidance procedure between a workpiece and an arbitrary tool
shape, based on the solid modeling technique. The post-processor
developed in the study can convert CL data to actual NC data, taking
account of the structure of machining centers. The main- and
post-processors are experimentally found effective.
|
|
Computer aided run-in of CNC-programmes
|
|
H. Weule (1), M. Klaiber
|
|
STC O, 41/1/1992, P.543
|
|
Keywords: Optimization of Manufacturing Systems, Shop-Floor-Orientation, Run-In of CNC-Programmes |
Abstract : To date the necessary rationalization procedures in the manufacturing
environment to achieve competitive advantage have taken place mostly,
from a high level, centralized point of view within organizations.
Additional competitive success can only be achieved through
consequential shop floor orientation.
Existing resources at the shop floor level, for example processing
proximity and manufacturing know-how can be used to advantage. In this
paper, a shop floor oriented approach is presented using the example of
reduction of the run-in time of CNC-Programmes. A computer aided method
for the run-in of CNC-Programmes is presented. Up to now this task has
been undertaken empirically.
The result is a transparent, well structured and thus target oriented
run-in system which assists the production planning process and which
leads to significant time saving.
|
|
A generalized kinematics model for three to five axis milling machines and their implementation in a CNC
|
|
A. Rüegg / P.E. Gygax (1)
|
|
STC O, 41/1/1992, P.547
|
|
Keywords: CNC, Kinematics |
Abstract : Currently, it is only possible to program the milling of complex shapes
by giving the axis cutter location points in ISO programs. With these
programs, it is not possible to apply corrections and fixture
compensation at the machine. Using a generalized kinematics model and a
uniform algorithm, working from the tool osculation point information,
it is possible to calculate the axis values for 3, 31/2, 4, 41/2 and 5
axis milling machines, thus supporting all the most important kinematic
designs of milling machines.
This method is implemented in a CNC controller, making it possible to
perform the kinematic calculations online on the machine. This has the
advantage that the same NC program can be used for different 5 axis
machines (with different geometry) without needing to rerun a
postprocessor program.
|
|
Block-like component CAD/CAM system for fully automated CAM processing
|
|
T. Hoshi (1)
|
|
STC O, 41/1/1992, P.551
|
|
Keywords: CAD-CAM |
Abstract : For the purpose of fully automating the transformation of CAD designed
product data into the information necessary for machining the product, a
new method of machining feature-based CAD/CAM has been investigated. By
modifying the existing Parametric Feature-Based CAD methodology into one
using only geometrical features machinable by defined cutting
technologies, a Machining Feature-Based CAD system has been developed,
by which it is possible to fully automate the processing of the
succeeding CAM tasks for fabrication of block-like components. The
CAD/CAM system has demonstrated a future possibility of highly automated
production of low volume high product-mix items of block-like components
which fall into a sub-set class of prismatics.
|
|
Model-based learning for diagnostic tasks
|
|
D. Specht, S. Weiss / G. Spur (1)
|
|
STC O, 41/1/1992, P.557
|
|
Keywords: Knowledge-Based Systems, Diagnostic Routines, Production |
Abstract : Despite many years of research, the two problems of knowledge
acquisition and maintenance of a growing knowledge base while preserving
consistency are still largely unsolved. This paper introduces an
approach which supports/ /the acquisition of diagnostic rules by
learning from examples representing the experiences of domain experts.
Using a model of the system to be diagnosed, these heuristic rules are
consistency checked before they are added to the knowledge-base.
Moreover, this model/ /constitutes a base for learning by transforming
analogous cases into actual problems when the system is operational.
|
|
Quality control in a flexible manufacturing cell
|
|
Z. Idelmerfaa, F. Lepage, J. Richard, M. Véron (1)
|
|
STC O, 41/1/1992, P.561
|
|
Keywords: Quality Control, Information System, Distributed Control, Flexible Manufacturing Cell |
Abstract : This paper presents a quality control loop architecture of a flexible
manufacturing cell. The cell is considered as an autonomous system which
produces parts and controls their quality and which manages its own
equipment and adapts its behavior according to the most recent
information. The quality control in the cell is based on two principles
concepts:
- management of all technical and quality information in the cell
information system,
- distributed control of the cell on several levels to perform
correction as fast as possible.
An application using a MAP local area network and SQL server realized in
the C.R.A.N, is described.
|
|
Clearance space in volumic dimensioning
|
|
M. Giodano, D. Duret, S. Tichadou, R. Arrieux (2)
|
|
STC O, 41/1/1992, P.565
|
|
Keywords: Tolerancing, Clearance, Functional Dimensioning |
Abstract : This paper presents a theoretical representation of the notion of
clearance between two parts connected by prismatic surfaces. In order to
characterize the clearance, the latter is associated to a fictive volume
represented in a three-dimensional space, which is not the real space of
the mechanical parts. The properties of the clearance volume are
studied. An example is presented. A generalization to the volumic case
is considered.
This method allows to develop a model that can be used from different
points of view: computer aided functional tolerancing, manufacturing and
control.
|
|
Simultaneous optimization of design and manufacturing tolerances with process (Machine) selection
|
|
C. Zhang, H.P. Wang, J.K. Li (2)
|
|
STC O, 41/1/1992, P.569
|
|
Keywords: Design and Manufacturing Tolerance, CAPP, Optimization |
Abstract : Tolerance design and synthesis is a major task of product and process
design and is in a period of extensive study due both to increased
demands for quality products and to increasing automation of machining
and assembly. Optimum tolerance design and synthesis ensures good
quality product at low cost. This paper provides an analysis of
simultaneous optimization of design and manufacturing tolerance
syntheses with consideration of process (machine) selection. The
tolerance synthesis problem is formulated as a mixed nonlinear
optimization model, which has as its objective the minimum total
manufacturing cost. A new global optimization algorithm simulated
annealing is coded to solve the optimization problem. An example for
illustrating the model and solution procedure is provided.
|
|
A new approach to manufacturing engineering education
|
|
O. Bjorke (1)
|
|
STC O, 41/1/1992, P.573
|
|
Keywords: Education, Systems |
Abstract : The paper points at the development towards a generalized systems
theory, which may be used to model the many topics covered in
manufacturing engineering education. This leads to the possibility to
harmonize the education in today's curricula consisting of separated
vertical blocks. The other important aspect in the paper is the trend
towards automatic formulation of system equations. These developments
will in the years to come force a major change in engineering curricula.
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STC P |
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Fiberoptics for in-line production measurement
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T. Pfeifer / W. König (1)
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STC P, 41/1/1992, P.577
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Keywords: Fiberoptics, Sensors, Threads, Metrology |
Abstract : The contribution deals with the laser-optical internal thread
measurement, with the aim to define quality-parameters, such as:
diameter, flank lead, break etc., automatically. The special fiberoptic
and laser-based sensor techniques as well as the data processing method
and evaluation algorithms are described.
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Distance-Distance method for straightness measurement
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G. X. Zhang (1), X.H. Chu, W. Tang, Z.Z. Jin
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STC P, 41/1/1992, P.581
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Keywords: Precision, Measurement, Straightness, Distance-Distance Method |
Abstract : A new method for straightness measurement based on distance measurement
from two reference points is introduced in this paper. The
distinguishing feature of this method is that it does not require a
straightness reference. It gives high accuracy due to high accuracy in
displacement measurement. A practical device used for quick distance
measurement based on a turnable laser interferometer with two end balls
is designed. Accuracy analysis of the instrument is given in detail.
Theoretical analysis and experiment show that this method gives high
accuracy in straightness and straightness error motion measurements.
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Angular measurement by means of rotation of linear gratings
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F.S. Jing, Y.C. Lin, Y.F. Zhou / G.X. Zhang (1)
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STC P, 41/1/1992, P.585
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Keywords: Precision Measurement, Moire Fringes, Microcomputer, Real Time |
Abstract : A newly patented technique for precision angular measurement by means of
mutual rotation of linear gratings is presented in this paper. An
analysis of variation of moire fringes based on theory of Fourier Optics
is given in accordance with the specific conditions, Processing of
signals is done in real time by a microprocessor. Both theory and
experiment show that angles can by measured more accurately with the aid
of the new technique.
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Automatic detection of defects among small pins-group
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Y. Furukawa (1), H. Sakuma
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STC P, 41/1/1992, P.589
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Keywords: Neural Network, Inspection, Image Processing |
Abstract : Some defects among a large number of electronic connector plug pins
inserted into a board being inspected manually today, can be automatized
by the proposed system which consists of an image processor associated
with neural network. Images which are caught by ITV camera is first
processed to binary signals, then input to the first layer of the
network, which is composed of other 2nd and 3rd layer, each of which is
programmed by so-called "Back-Propagation" algorithm. The network learns
many types of defects in advance and decides strength of each net, with
which compares the actual image of pins. Fundamental features of the
proposed system were made clear and the network could well detect such
defects as beaded, buckled and mis-positioned pins.
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Three dimensional cognitive system for quick perception and inspection of mechanical part using computer tomography
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K. Yamazaki (2)
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STC P, 41/1/1992, P.593
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Keywords: Dimensional Measurement, Image Processing, Geometric Modelling |
Abstract : The paper deals with a new method for the efficient and autonomous
perception and inspection of three dimensional geometry of a mechanical
part. The method developed is based on a high power X-ray CT (Computer
Tomography) applied image capturing and three dimensional computer image
processing. The system was developed such that a geometric model of the
part can automatically be reconstructed as a computer software model
with newly developed algorithms which can autonomously perceive three
dimensional geometry features of the part. The feasibility of the
proposed method was successful demonstrated by the experiments using the
developed system.
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An universal algorithm for the alignment of any sculptured surface
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G. Goch, U. Tschudi / J. Pettavel (1)
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STC P, 41/1/1992, P.597
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Keywords: Coordinate Measurement Techniques, Sculptured Surfaces, Alignment and Approximation, Deviation Function |
Abstract : Sculptured surfaces are often given/ /by a set of discrete nominal
points and the corresponding normal directions (e.g. bevel gear flanks,
turbine blades). The alignment of these workpieces leads to significant
problems, as conventional algorithms based on the L_2 -norm (Gauss) or
Tschebyscheff-norm (T-norm) require a surface description by
mathematical functions. In this paper a new alignment-algorithm will be
explained, which needs as input data only a set of nominal points
together with their normal directions and which delivers as output data
the alignment operator (rotation matrix and displacement vector). Both
L_2 -norm and T-norm are available as objective functions. The surface
can be contiguous or composed of different areas distributed over the
workpiece (e.g. different teeth-flanks); no functional description is
necessary. Basic mathematics will be discussed and results obtained by
measurements will be given.
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Performance analysis of feed-drive-system in diamond turning by machining specified test samples
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T. Bispink / M. Weck (1)
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STC P, 41/1/1992, P.601
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Keywords: Diamond Turning Machines, Form Accuracy, Tests |
Abstract : In the field of ultraprecision machining proper performance of feed
drive systems is necessary. Smallest depths of cut, smooth surfaces and
minimal shape errors of complex parts are required.
To test the behavior of high precision feed drive systems several direct
and indirect analysis methods can be applied. In this report three
indirect test methods are presented. By machining and evaluation of
specified workpiece samples information about the feed drive behavior
are obtained. Correlations between surface-shape, surface-describing
parameters and the position data of the cutting tool are made. The work
is to be considered as a contribution to the testing of ultraprecision
machine tools.
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The optimum crystal plane of nature diamond tool for precision machining
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Z.J. Yuan (1), J.C. He, Y.X. Yao
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STC P, 41/1/1992, P.605
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Keywords: Ultra-Precision Machining, Single Crystals, Diamond Tools, Friction, Wear Resistance |
Abstract : Because of the strong anisotropism of single crystal diamond, the
optimization of crystal plane becomes very important and crucial in
manufacturing of single point diamond tool. The friction states between
the rake and the flank of diamond tool and workpiece materials affect
shear deformation, tool wear and the quality of machined surface
directly. In this paper, the writers investigated the friction
coefficients between diamond oriented various crystallographic direction
and non-ferrous metals by experiment simulating friction states of
ultra-precision machining, and find out that the friction coefficients
is not only different with different crystal planes, but also different
with different directions in the same crystal plane. These experiments
lead to the conclusion that (100) plane is the optimum plane for the
rake and the flank of single point diamond tool.
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STC S |
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Predicting microcontact spots size distribution in contact problems
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L. Klimczak / J. Kaczmarek (1)
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STC S, 41/1/1992, P.609
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Keywords: Roughness, Real Contact Area, Contour Map, Contact Spots Size Distribution |
Abstract : When two parts are in contact surface roughness causes contact to occur
at discrete contact points. Number of contact spots and their individual
size are essential information to understand many tribological
situations. They can be predicted from geometrical intersection between
surface and plane ? the surface roughness contour map. In this paper,
variation of contact spots size distribution with intersection level was
evaluated from contour maps of surface produced by common machining
processes. This was compared with contact spots distribution obtained
for surfaces deformed plastically.
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Surface studies during indexable drilling with coated carbides of different geometry
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V.C. Venkatesh (1), W. Xue, D.T. Quinto
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STC S, 41/1/1992, P.613
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Keywords: Indexable Drill, Surface Integrity, Negative Point Angle, Coated Carbides |
Abstract : Three types of indexable drills (A, B, and C) were used to drill 1018
steel, copper, and aluminum alloys. The inserts used were 80° rhomboid,
square, and trigon shaped giving different side cutting edge angles
(SCEAs). The inserts had three types/ /of coatings and one uncoated:
Drill A TiC (CVD), Drill BI TiN/A1_2 ,O_3 , multi-layer (CVD), Drill B2
TiN (CVD), and Drill C (uncoated). In one type of drill both outer and
inner inserts had only one cutting edge each, whereas in the other two
types, two cutting edges were presented. Roundness, surface roughness,
angularity, waviness, chip root, photoelastic, microscopic, and X-ray
diffraction studies were carried out. Drill A with a -ve SCEA and a TiC
coating on a cobalt enriched surface. and Drill B1 with a TiN/A1_2 O_3
coating gave the best surface finish and roundness values and the
reasons for this are highlighted in this paper.
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Robot kinematics for the free-form polishing of deformable Bezier-type surfaces
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K.T. Yap (2), Y. Yokokohji
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STC S, 41/1/1992, P.617
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Keywords: Hybrid Control, Electrochemical Polishing, Bezier Surfaces, Contact Sensors |
Abstract : The exact model of dynamic forces required to control a robot to follow
a Bezier-type surface is developed in this paper. Implementation using a
contact sensor to enable the polishing tool fixed at the end-effector
for hybrid controlled is discussed. The experimental set-up led to the
discarding of terms in the original kinematic equations which are
insignificant compared to friction and actuator dynamics due to slow
tool advance velocity involved in electro-chemical polishing. Some
problems relating to the "look ahead" mechanical sensor are also addressed.
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The use of 3D topographic analysis to determine the micro-geometric transfer characteristics of textured sheet surfaces through rolling
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K.J. Stout, P.J. Sullivan / P.A. McKeown (1)
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STC S, 41/1/1992, P.621
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Keywords: 3D Surface Topography, Surface Analysis, Textured Sheet, Rolling, 3D Parameters |
Abstract : Traditionally, rolling mills were used for the purposes of flattening
metal sheet, and reducing its thickness. However recently their use has
been extended to provide a method for producing sheet with specified
textures. The transfer characteristics of a textured roll to a sheet may
be investigated qualitatively and quantitatively using a number of
different approaches. Quantitative techniques include the use of
2-dimensional profilometry which is obviously inherently limited in its
ability to characterize a 3-dimensional (3-D) surface.
Although 3-D surface topography measurement systems have been available
for/ /some time, 3-D characterization techniques are still in their
infancy (particularly with functional significance). The aim of/ /this
paper is to show how the use of 3-D characterization techniques may be
used to qualitatively and quantitatively analyze engineering surfaces.
In this paper the texture transfer characteristics of sheet rolling is
explored and the extent of transfer is determined. The technique
employed shows how the integrity of topography transfer may be
established with a limited basic set of 3-D parameters through the
analysis of parameter variation. Art area material ratio curve is also
introduced and its usefulness in the comparison of the amplitude
distributions of two surfaces is demonstrated.
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