CIRP ANNALS 1991
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STC A |
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Assembly of large products
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G. Boothroyd (1), M. Fairfield
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STC A, 40/1/1991, P.1
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Keywords: Assembly, Design, Acquisition, Handling |
Abstract : The need for a method of estimating assembly times for large products
during the product design phase is discussed. An approach to the
development of a database of part acquisition and handling times is
described and some preliminary results are presented. Comments and
conclusions are made regarding the feasibility of the proposed approach.
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Pre-fabricated carbide tips handlin
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D. Milutinovic, M. Pilipovic / M. Kalajdzic (1)
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STC A, 40/1/1991, P.5
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Keywords: Handling, Carbide Inserts, Manipulation System |
Abstract : The solving of the problem of automated handling of pre-fabricated
carbide tips aimed at improving and maintaining the quality,
productivity and humanization of work is a very complex engineering task.
The complexity of the problem of automated handling primarily relates to
the possibility of easy damageability of pre-fabricated tips very
limited space and short time cycle for their taking out of the press.
The paper in detail analyses this problem and presents a developed
concept of a manipulation modular-based system. In comparison with the
existing systems the basic advantage was achieved i.e. the flexibility
and sophisticated control. This developed system solves the problem of
the handling of pre-fabricated tips in small companies.
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Kinematic calibration of SCARA robot with condition number and error Map method
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S. Toyama, S. Hatae, T. Haga / K. Kinoshita (1)
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STC A, 40/1/1991, P.9
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Keywords: Assembly Machines, Calibration, Error Analysis |
Abstract : This paper presents a new kinematic calibration method based on
condition number and an error map method for SCARA robots. The geometric
parameters can be identified more precisely by measuring the positions
of a hand with minimum condition number configuration. Furthermore. the
error map method improves the accuracy of geometric parameters. The
experimental results demonstrate that this calibration method made the
maximum absolute positioning error of a typical SCARA.DD robot less than
0.25 mm all over the working area, while the maximum error was 2.20 mm
in the case of the conventional method.
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Choice of optimal configurations for flexible (readjustible) assembly lines by purposeful search
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A.I. Dashchenko / T.N. Loladze (1)
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STC A, 40/1/1991, P.13
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Keywords: Assembly, CAD |
Abstract : A comprehensive CAD system is outlined for grouped assembly processes in
the automobile industry. The ideology is described more thoroughly of
developing a configuration choosing module. Examples are reported of
designing assembly lines for car electric systems.
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Robotized assembly of modular fixtures
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F. Giusti (1), M. Santochi (2), G. Dini
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STC A, 40/1/1991, P.17
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Keywords: Assembly, Planning, Fixtures |
Abstract : A prototype plant for the robotized assembly of modular fixtures for NC
machining centers is described. After presenting a brief summary of the
present tendencies relative to the design, preparation and management of
the fixtures, the plant and its components are described in their
general structure, posing particular focus on the geometric and
functional features of the modular elements, designed in order to
facilitate the automatic operations of manipulation and assembly. The
plant is controlled by a software structured for design of fixture
configuration, planning of the assembly sequence and off-line
programming of the robot. Results obtained in assembly tests are also
discussed, and emphasis is placed on the more critical aspects linked to
the automation of this important operation. In conclusion, the possible
applications of the automatic assembly of fixtures for FMS plants are
proposed.
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SMD reflow soldering : a thermal process model
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P.P. Conway, A.O. Orgunjimi, P.M. Sargent, A.C.T. Tang, D.C. Walley, D.J. Williams / A.W.J. Chisholm (1)
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STC A, 40/1/1991, P.21
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Keywords: Assembly, Electronics, Soldering |
Abstract : This paper presents a number of numerical process models of the
infra-red reflow soldering process, the major joining process for
surface mount electronic assemblies. The aim of this work is to
investigate the key process and design variables and their effect on
joint quality in the final assembly. The paper includes models of a bare
printed circuit board and "J and Gull-Win," leaded components on a
printed circuit board all passing through an infra red oven. The process
models are based on the IDEAS modeling suite and TMG thermal solver and
are likely to find application process design.
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STC C |
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Computerized end-milling force predictions with cutting models allowing for eccentricity and cutter deflections
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E.J.A. Armarego (1), N.P. Deshpande
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STC C, 40/1/1991, P.25
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Keywords: End-Milling, Eccentricity, Cutting Forces, Milling, CAD/CAM |
Abstract : In this paper further developments of computer based mechanics of
cutting models and software modules for the prediction of the average
and fluctuating force components and torque in End milling are
considered and assessed by numerical simulation and experimental
testing. Three modes are considered namely, the 'ideal' model for rigid
cutters with no eccentricity, the rigid cutter 'eccentricity' model and
a more comprehensive 'deflection' modes allowing for both eccentricity
and cutter deflections. It is shown that the 'idea:.' model provides
useful qualitative tends for the average forces and torques which /are
/similar for a:1 three models but yields poor qualitative force
fluctuation predictions. The 'eccentricity' model yields good
predictions of the average forces and torque while the fluctuation
predictions are also good out deteriorate for unfavourable cutter
deflection while the 'deflection' model provides the best predictions
and correlation with the 350 experimental test results but at the
expense of excessive computer processing time. The practical Implication
of these models and the importance of both eccentricity/ /and cone-
deflection en the force fluctuations are discussed.
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General end-milling force algorithms for CAD systems
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Y. Altintas, A. Spence / J. Tlusty (1)
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STC C, 40/1/1991, P.31
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Keywords: Milling, Solid Modelling, Cutting Forces |
Abstract : This paper presents an efficient milling mechanics simulation system for
use with solid modeler based tool path generation algorithms. The
technique provides computationally efficient cutting force predictions
for end milling of general part shapes. First, the part is described
using the Constructive Solid Geometry representation scheme. Along the
cutter path the tool-workpiece interaction is represented using
immersion arc segments obtained by intersecting the cutter with each
part feature. Next, a cutting mechanics model is used to predict the
instantaneous, average and peak forces, and maximum cutter deflections
left on the finished part surface. By separating the cutter constants
from the part geometry, the model allows automatic feed rate scheduling
to satisfy end milling constraints. Verification of the method by both
simulation and experiment is included.
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A tool temperature - tool-life relationship covering a wide range of cutting data
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B. Colding (1)
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STC C, 40/1/1991, P.35
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Keywords: Cutting, Temperature, Tool-life |
Abstract : The paper shows that maximum tool-life, or minimum temperature, for any
given metal removal rate of a cutting tool or grinding wheel is governed
by the principle of minimum thermal energy, resulting in one single
relationship between metal removal rate per unit cutting edge length and
tool-life, or temperature, for each tool - work combination. A tool
temperature relationship, of the same form as the author's tool-life
relationship, is derived, the constants of which can be calculated from
temperature tests and two tool-life calibration tests.
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On-line estimation of groove wear in the minor cutting edge for finish-machining
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Y. Yao, X.D. Fang, G. Arndt (1)
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STC C, 40/1/1991, P.41
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Keywords: Tool Wear, Cutting Edges, Statistical Analysis |
Abstract : The paper investigates the effective detection and estimation of groove
wear at the minor cutting edge, which has a vital influence on surface
quality in finish-machining. During bar-turning experiments with
different cutting conditions, a miniature 3-D accelerometer, mounted in
close vicinity to the tool tip, was used to measure the multivariate
vibration signal produced by the turning process. The stochastic signal
was modeled as autoregressive vector difference equations, and multiple
dispersion analysis was used to quantify the complex interactions among
various variables. It was found that the characteristic ingredient of
vibration in the thrust direction, complemented by that in the main
cutting direction, signifies effectively the critical point at which
grooves are being "chiseled out", surface roughness is deteriorating
rapidly, and subsequently the finishing-tool needs to be replaced. The
results are interpreted on a physically sound basis. The results also
show that the algorithm developed is a feasible approach to on-line
monitoring of minor cutting edge groove wear in finish-machining.
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Tool life scatter when milling with TIN coated HISS indexible inserts
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G. Byrne, B. Bienia / G. Duelen (1)
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STC C, 40/1/1991, P.45
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Keywords: Cutting, Milling, Tool Life Scatter, Coated Cutting Tools |
Abstract : Results of experimental investigations into the tool life scatter which
occurs in face milling with titanium nitride coated high speed steel
indexible inserts are presented and discussed The tools investigated
were coated under closely controlled conditions using Physical Vapour
Deposition (PVD) technology. The scatter between the four corners of a
single indexible insert was found to be very significant. Many important
questions in relation to substrate preparation for coating, coating
process conditions and method of cutting tool implementation in the
machining process arise as a result of the analysis undertaken. It is
shown that the orientation, location and method of fixing of the cutting
tools in the coating chamber effect the tool life scatter.
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Cutting performance and wear characteristics of an alumina-zirconia ceramic tool in high speed face milling
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N. Narutaki, Y. Yamane, K. Hayashi / T. Hoshi (1)
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STC C, 40/1/1991, P.49
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Keywords: Cutting, Ceramic Tools |
Abstract : High speed face milling for plain carbon steel S45C was carried out with
ceramic tools. Pure alumina, TIC added alumina, and zirconia toughened
alumina ceramic tools were mainly used. Among the tested ceramic tools,
the zirconia toughened alumina ceramic tool sowed the largest crater
wear resistance in high speed face milling. However, in turning the same
steel, the crater wear resistance of the ceramic tool was almost the
same degree as compared to the other ceramic tools. The superior wear
resistance of the zirconia toughened alumina ceramic tool is based on
its stability for the reaction to Fe0 at high temperature.
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Investigation of face turning on NC lathes
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E. Kuljanic (1)
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STC C, 40/1/1991, P.53
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Keywords: Cutting, Face Turning, CNC lathes, Productivity Increase, Tool Life, Surface Roughness |
Abstract : This paper presents the results of a research on face turning on CNC
lathes at constant cutting speed and at constant spindle revolutions. In
both cases the surface roughness is examined by using different machine
tools, with different tools, and at different cutting conditions, a
comparison is made of cutting time in face turning at constant cutting
speed and at constant spindle revolution. Furthermore, this paper deals
with a comparison of tool wear, tool life, the area of machined surface
and the gain for obtained at constant cutting speed and at constant
spindle revolutions. The cutting time is shorter by approximately 45%37;
when face turning os done at constant cutting speed.
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Effect of micro-cracks in CVD coated layer on transverse rupture strength and chip resistance
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S. Katayama, M. Hasimura, T. Tanaka, H. Imamura / K. Uehara (1)
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STC C, 40/1/1991, P.57
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Keywords: Cutting, Coated Carbides, Residual Stresses |
Abstract : Micro-cracks were artificially induced in the CVD coated layers on a
cemented carbide tool by a mechanical method. The cracks have beneficial
effects on the transverse rupture strength and the chipping resistance
during interrupted cutting. With decreasing mean value of distances
between cracks from 400 to 20 mm, the transverse rupture strength
increased from 1.2 to 2.05 GPa and the chipping resistance about
doubled. It seems that/ /the improvements are closely related to the
relief of residual tensile stress in the coatings.
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A. J-integral approach to material removal mechanisms in microcutting of ceramics
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K. Ueda, T. Surgita, H. Hiraga / K. Iwata (1)
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STC C, 40/1/1991, P.61
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Keywords: Cutting, Ceramics, Brittle-Ductile Transition |
Abstract : An approach to analyzing material removal mechanisms in micro-cutting of
ceramics is described. The approach is based of the J-integral method
capable of elastic-plastic fracture mechanisms. The J-integral value
around a track ahead of the cutting edge is determined using the finite
element method. Both the brittle and ductile mode material removal
mechanisms are analyzed by considering crack propagation and plastic
deformation behavior. The brittle-ductile transition is elucidated for
the selected ceramics materials and the applicability of the ductile
mode removal ids also discussed in terms of the material properties and
cutting condition.
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Bluntness of the tool and process forces in high-precision cutting
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D.A. Taminiau, J.H. Dautzenberg (2)
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STC C, 40/1/1991, P.65
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Keywords: Cutting, Cutting Forces, Tool Wear |
Abstract : The influence of bluntness of the cutting tool edge is considerable when
making smaller cuts, particularly in high precision cutting. In this
paper its influence on the process forces is investigated. It has been
approximated by a rounded tool edge. In that case, Abdelmoneim's model
for determining the tool forces when cutting with a rounded tool edge,
is applicable.
Rough cutting experiments have been carried out using tools ground with
large edge radii. Force measurements have been compared with the
theoretical results from Abdelmoneim's model. In addition the model has
also been used for high-precision cutting experiments.
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Energy dissipation in the ultra-precision machining of copper
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D.A. Lucca, R.L. Rhorer, R. Komanduri (1)
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STC C, 40/1/1991, P.69
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Keywords: Cutting, Ultra-Precision Machining, Specific Energy |
Abstract : An experimental study of the forces involved in the orthogonal single
point diamond machining of oxygen free high conductivity (OFHC) copper
and fine grain copper was performed. Depths of cut ranged from 15 mm
down to 0.025 mm and cutting speeds ranged from 6 m/min to 107.7 m/min.
cutting and thrust forces were measured. The total specific energy is
seen to significantly increase at small depths of cut, consistent with
observations reported in the literature. An overall energy balance
indicates that at depths of cut below several micrometers shearing in
the shear zone is unable to account for the observed energies. Flank
face rubbing due to workpiece material elastic recovery and plowing due
to the edge radius of the tool may take on increased roles as mechanisms
of mechanical energy dissipation in micro-machining.
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Chip control in cut-off tools
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J. Rotberg, A. Ber (1), R. Wertheim (1)
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STC C, 40/1/1991, P.73
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Keywords: Cutting, Grooving, Chip Formation |
Abstract : This paper deals with the family of "Cut-Off" tools. In said family of
tools, the role of chip control, i.e. chip formation and chip flow, is
quite essential, since it should enable the extraction of the generated
chip but of the machined slot without causing any damage to the
workpiece. It is important not only to have chip curling, but also
material flow toward center of rake face in order to narrow the chip in
comparison to the slot. Chip formation characteristics, chip
cross-section and chip curling were investigated experimentally while
influencing parameters such as insert geometry, arid cutting conditions
were studied. The study of the chip formation at the cross-section plane
(perpendicular to the chip flow direction) was specially emphasized. The
results lead to the understanding and definition of tool performance in
terms of insert geometry, cutting conditions and chip form.
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Formation of flank build-up in cutting magnesium alloys
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N. Tomac, K. Tonnessen / F. O. Rasch (1)
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STC C, 40/1/1991, P.79
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Keywords: Cutting, Magnesium, Build-up |
Abstract : Flank build-up on HM cutting edges at speeds in excess of approximately
600 m/min may constitute a problem when running magnesium alloys. SEM
analyses of workpiece materials, tool inserts with flank build-up and
flank build-up itself indicate that manganese compounds play an
important role in forming very card particles and through a high degree
of attraction to the tool material. Three Mg-Al-Zn alloys with different
manganese content were turned under different cutting conditions in
order to determine the tool-workpiece interaction at different cutting
speeds. All three alloys gave the same type of flank build-up, the
critical cutting speed which expresses the tendency to form flank
built-up, was however different for the three alloys.
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Burrless drilling by means of ultrasonic vibration
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H. Takeyama (1), S.Kato
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STC C, 40/1/1991, P.83
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Keywords: Ultrasonic Drilling, Burr, Material Deterioration in Drilling, Burrless Drilling, Radial Peripheral Lip Drill |
Abstract : In order to achieve edge integrity in view of burr, flaking, chipping,
material deterioration, etc, in drilling operations, ultrasonic
vibration has been applied in the direction of drill feed. The
multiplying effect of ultrasonic vibration and newly developed radial
peripheral lip drill has been experimentally demonstrated to be
extremely effective for preventing burr and material deterioration et
the exit of drilled hole of aluminum and glassfiber reinforced plastics.
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Wälzfräsen von Kupplungs - Planverzahnungen - Analyse der Verfahrenskinematk durch Simulation
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L. Cronjäger (1), A. Steinwachs
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STC C, 40/1/1991, P.87
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Keywords: Hobbing, Crown Gears, Tooth Clutches |
Abstract : The machining of crown gear rims, applied in tooth clutches for torque
transmission, usually is done by milling using the indexing method,
involving long machining times and the risk of edge contact. The paper
deals with a new hobbing method, that enables an economical manufacture
of spirally curved crown gears with conventional spur gear generating
machines. In order to optimize the contact characteristic and the tool
design, the kinematics of the procedure have been analyzed by computer
simulation, so that the shape of the generated teeth is calculable just
as well as the chip width and the working clearance angles.
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The workpiece material-laser interaction and the laser-assisted machining
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G. Marot, L.J. Fan, A. Tarrats, p. Cohen, J.P. Longuemard / A. Moisan (1)
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STC C, 40/1/1991, P.91
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Keywords: Laser, Laser-assisted Machining, Roughness, Laser-Material Interaction, Diffusion Energy |
Abstract : During the laser-assisted machining, only a small part of the laser beam
is absorbed by the workpiece. So it seems useful to study the diffused
beam angular distribution, and to find out the relation between this
distribution and the surface finish, in certain conditions is impossible
to get a better efficiency for the laser-material interaction.
This paper describes an experimental study of this kind, and some
conclusions which can be tough from a practical point of view.
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Operation planning based on cutting process models
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M.D. Tsal, S. Takata (2), M. Inul, F. Kimura (2), T. Sata (1)
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STC C, 40/1/1991, P.95
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Keywords: Process Planning, Milling |
Abstract : This paper describes model based operation planning for pocket milling
operations. The tool path and cutting conditions are determined based on
the geometric model of workpieces and the physical models of the cutting
process. The tool path is generated by using the Voronoi diagram of a
cutting area. Cutting conditions to achieve the maximum metal removal
rate are determined by evaluating the physical models of cutting torque,
chatter vibration, and machining error. To maintain a favorable cutting
state, the radial depth of cut is controlled by modifying the tool path
distance at the circle path segment and by adding additional tool path
segments at the corner. Examples are shown to demonstrate the
effectiveness of the method.
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A yugoslav approach to decision support for optimization of FMS technologies
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L. Lukic, D. Polajnar, V. Solaja (1)
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STC C, 40/1/1991, P.99
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Keywords: FMS |
Abstract : A generalization method of determining realistic machinability
parameters in chip-removal cutting processes is presented in this paper.
This method integrates generalized and verified machining functions with
analytical dependences obtained from experimental data and machining
procedures. Reliable and applicable technological models of machining
processes are defined by this method, which are the base of a computer
decision support system in the design and optimization of FMS
technologies. The results are built into the relational database system
and the algorithm for decision support system.
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An atomistric analysis of nanometric chip removal as affected by tool-work interaction in diamond turning
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N. Ikawa (1), S. Shimada, H. Tanaka, G. Ohmori
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STC C, 40/1/1991, P.551
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Keywords: Cutting, Micromachining, Accuracy |
Abstract : This paper discuss the significance of the minimum thickness of cut
which id defined as the minimum uncut thickness of chip removed from
worksurface at a cutting edge under perfect performance of a metal
cutting system. Following a brief look at the relation between the
minimum thickness of cut and extreme machining accuracy attainable for a
specific cutting condition, it is shown that a very fine chip the uncut
this thickness of which is at the order of 1 nm is obtained in an
experimental face turning by a well-defined diamond tool. To understand
nanometric chip removal process, a computer simulation using an atomic
model is made. The analysis of the experimental results aided by the
computer simulation shows that, while the minimum thickness of cut is
affected by the tool a workmaterial, interaction to a certain degree, it
is more strongly affected by the sharpness of cutting edge and that the
minimum thickness of cut may be at the order of 1/10 of the cutting edge
radius.
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Ultra-precision diamond turning of stainless steel by applying ultrasonic vibration
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T. Moriwaki (2), E. Shamoto
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STC C, 40/1/1991, P.559
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Keywords: Ultra-Precision Cutting, Single Crystal Diamond Tool, Ultrasonic Vibration Cutting, Stainless Steel |
Abstract : The paper presents experimental results of ultra-precision diamond
turning of stainless steel. The steel cannot be machined normally by
diamond tools due to excessive wear, although there are great demands
for ultra-precision machining of the steel family. The ultra-precision
diamond turning of stainless steel was realized by applying ultrasonic
vibration of 40 kHz to the single crystal diamond tool in the cutting
direction. The surface roughness of less than 0.03 ?m in Rmax is
obtained. The cutting test results up to 1600 m in the cutting distance
are also presented.
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STC Dn |
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A CAD integrated "knowledge based system" for the design of die cast components
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J. Corbett (2), J. Woodward
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STC Dn, 40/1/1991, P.103
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Keywords: Design, Expert Systems, Castings |
Abstract : The paper shows haw knowledge based systems, and in particular features
representation, can be applied in the area of design for manufacture to
alert the designer of any potential production problems, before he
commits his design to manufacture. Die casting was the subject for this
initial research as it was a strategically important process in the
collaborating company's drive to reduce timescales and costs while
improving quality. The phases of knowledge acquisition, knowledge
representation and the CAD customized modeler interface are described
for the system which supplies appropriate design for manufacture
expertise 'up-front' at the point of design.
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Design for assembly within concurrent engineering
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E. Molloy, H. Yang, J. Browne / B.J. Davies (1)
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STC Dn, 40/1/1991, P.107
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Keywords: Design, Assemblies, Concurrent Engineering |
Abstract : Design For Assembly (DFA) is identified as an important strategy for the
reduction of product manufacturing costs. In this paper the background
to Design For Assembly (DFA) is described, and a method for the
representation of DFA knowledge adopted. The problem of Computer Aided
Assembly Process Planning CAAPP) is also addressed, and an approach_
using the disassembly sequence is developed using product information
generated using a feature-based CAD system. This feature information is
also used to generate a graph-type representation of the product
structure for use in an integrated CAAPP/DFA system.
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Feature-based reasoning in fixture design
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W. Dong, W.R. De Vries (2), M.J. Wozny
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STC Dn, 40/1/1991, P.111
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Keywords: Design, Fixture, Feature |
Abstract : Features or mechanical design are generally defined is entities which
describe both the form and function of/ /the design. This geometric and
process related design information facilitates the design of tooling and
fixture; for manufacturing a part. This paper investigates the use of
features for fixture design, concentrating on the selection of locating
elements and the identification of locating surfaces or workpiece
positioning.
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Automatic generation of product disassembly sequences
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A.K. Subramani, p. Dewhurst (1)
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STC Dn, 40/1/1991, P.115
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Keywords: Design, Service, Assembly, Disassembly |
Abstract : Assessment of service difficulties at the concept stages of product
design coupled with an existing methodology for estimating assembly
difficulties would help in the assessment of life cycle costs. The
authors are investigating procedures which can be used to assess service
difficulties and costs at the early stages of product design. A central
part of this work is generation of required disassembly sequences for
identified service or repair items. This paper describes a mode of
assemblies which as been developed for this purpose with the associated
search algorithms. To facilitate the required search procedures, the
concept of a disassembly diagram was introduced. The relationships
between this diagram, the assembly model and the search procedures are
illustrated in the paper by a simple example.
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Design procedure of intelligent machines and its application ot AGV
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Y. Furukawa (2), N. Moronuki
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STC Dn, 40/1/1991, P.119
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Keywords: Design, Intelligent Machine, Information |
Abstract : This paper proposes a concept and procedure of intelligent machine
design. First, a concept of functional design for each requirement is
described. In this study, the information flow of the system is
considered referring the human's action and information flow. Then. a
concept and procedure to construct a hierarchical system is introduced
in which each element's load balance is considered. In order to verify
this concept, an intelligent AGV was developed. This AGV recognizes the
operator's voice command, decides an action plan by itself, and travels
autonomously recognizing the environment with ultrasonic sensors.
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Conceptual design of control strategies for hot rolling
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J.S. Gunasekera (2), J.C. Malas
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STC Dn, 40/1/1991, P.123
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Keywords: Conceptual Design, Hot Rolling, Thin Sheets |
Abstract : This paper deals with the application of 'axiomatic' approach to the
conceptual design of a hot rolling process. Functional requirements
{FRs} of the rolling process are governed by the metallurgical and shape
requirements of the product. Design parameters {DPs} which are capable
of controlling the process in order to achieve the desired {FRs} are
identified. A design matrix which relates {FRs} and {DPs} is then
derived and re-arranged ro maintain independency of the parameters and
'decouple" the design. Results obtained using this approach will form a
basis for subsequent, detailed design of the process.
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A pattern directed design system for machine assembly
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F. Kimura (2), H. Suzuki, I. Tanaka
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STC Dn, 40/1/1991, P.127
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Keywords: Computer Aided Design, Features, Routine Design |
Abstract : A system is proposed to facilitate the pattern directed machine design
process in which routine design of mechanical elements is often used as
a vocabulary. The design knowledge about the routine design, which is
found in handbooks or catalogs, is stored as design features. A design
feature/ /consists of the parametric definition of its parts shapes and
the knowledge for detailing those shapes. To represent machine
assemblies designers locate design features in work space, and relate
them with design constraints. The system determines the detail of design
features so that the constraints are satisfied, and solid models of part
shapes are generated. A prototype system is implemented on an object
oriented language Flavor, and some examples are shown.
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Design for manufacture analysis : early estimates of tool costs for sintered parts
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W.A. Knignt (2)
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STC Dn, 40/1/1991, P.131
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Keywords: Design for Manufacture, Powder Metallurgy |
Abstract : Early decisions on processing methods and part features should be based
on quantitative assessments of manufacturing costs. This paper describes
a methodology for determining tooling costs for processing parts
manufactured by sintering from powder metals. This procedure is intended
to be used at the early design stages when alternative part
configurations and processes are being considered. The results of
application to a range of parts are included. This procedure is included
in a software tool for use by designers to facilitate early design
decisions on part features and processing methods.
|
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PDGL - An human and computer readable language for efficient feature based designing
|
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F.L. Krause (2), S. Kramer, E. Rieger
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STC Dn, 40/1/1991, P.135
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|
Keywords: PDGL |
Abstract : For high level and efficient computer aided design it is necessary to
provide the possibility of object oriented modeling. A language has been
developed to describe features in an object oriented manner including
their technological semantics. The resulting generic feature templates
are interpreted by the modeling system during runtime. Therefore the
specific feature takes the actual design into account. By computing
derivable parameters automatically, integrating related standard tables
and by regarding design rules, features behave according to their
associated semantics. During product gestaltung with features, the user
works in his semantical environment and not only with geometric
primitives. The concept for the feature design language as well as some
examples demonstrating the advantages of the concept are presented.
|
|
A rule based systems approach to the design of manufacturing cells
|
|
A.K. Kochhar, H. Pegler / J.A. McGeough (1)
|
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STC Dn, 40/1/1991, P.139
|
|
Keywords: Design, Cells, Systems |
Abstract : This paper describes a three staged systems approach, and the associated
rule based procedures, which may be used for the steady state design of
assembly cells incorporating the highly effective and successful
Just-In-Time philosophy. The approach involves the assessment of
assembly alternatives, the comparison of capacity alternatives, and the
specification of cells arrangement. The important rules, based on
information elicited from experts in the design and implementation of
assembly cells are described. The approach and the rules described make
it possible to take account of the large number of the interrelated
factors. The rules may be used on their own or as part of a computer
based tool box provided to the manufacturing systems designers.
|
|
Integration of simulation, learning and optimization to support engineering design
|
|
S.C.Y. Lu (2), D.K. Tcheng, S. Yerramaredy
|
|
STC Dn, 40/1/1991, P.143
|
|
Keywords: Design, Simulation, Knowledge Processing Technology |
Abstract : This paper presents a knowledge processing system, called AIMS (Adaptive
and Interactive Modeling System), which integrates simulation, learning,
and optimization techniques to perform multi-objective model formation
and model utilization tasks. The system is aimed at improving the
utility of simulation programs for analysis and synthesis during various
stages of design. In this paper, we demonstrate the use of AIMS with an
internal combustion engine simulator. A set of models, which trade off
accuracy with speed, are induced by AIMS based on examples generated
from the simulator. When comparing induced models with the original
simulator, we observe orders of magnitude improvement in model's
execution speed with only a minor compromise in model's predictive accuracy.
|
|
A framework for an object/rule-based automated fixture design system
|
|
A.Y.C. Nee (1), A.S. Kumar
|
|
STC Dn, 40/1/1991, P.147
|
|
Keywords: Jigs and Fixtures, Knowledge Based Systems, Design |
Abstract : Fixture design has traditionally been regarded as a manual process due
to extensive requirements of heuristic knowledge and skilled
craftsmanship. This paper presents a framework for automated fixture
design using a solid modeler, an object/rule-based expert system and X
Window. Geometric and textual information are extracted from the solid
modeler to determine the type of operation and number of set-ups
required. Locating, supporting and clamping planes and points are
identified using rule-based as well as mathematical analysis. The final
output represents fixture assembly sequences and the feasibility for
robotic assembly is also discussed.
|
|
Feature based part database design and automatic forming of part families for GT
|
|
B. Logar, J. Peklenik (1)
|
|
STC Dn, 40/1/1991, P.153
|
|
Keywords: Entity-Relationship Model, Relational Part Database, Feature Based Design, Binary Coding Matrix, Part Families |
Abstract : The contribution deals with the feature based part database (engineering
model) design, realized through the CAD program FAMOS. The system
enables the forming of part families by automatic generation of the part
binary coding matrix or part classification. The part database has a
relational structure including the geometrical, dimensional, and
tolerance features.
|
|
CSG representation as a basis for extraction of machining features
|
|
M. Shpitalni (1), A. Fisher
|
|
STC Dn, 40/1/1991, P.157
|
|
Keywords: images/cirpfichiers/annals/ CAD/CAM, Feature Extraction, Machining Features, CSG |
Abstract : The process of converting a given design into the form of a raw_ stock
minus a series of machining features is known as machining feature
extraction. A method has been developed for extracting of machining
features of different types: simple, compound, complex and nested. The
proposed method is based upon extracting the disjointed machining
regions comprising the total volume to be machined first, and then
dealing with each disjointed machining region independently. The
extraction of the machining regions is performed by manipulating the CSG
tree representing the object, evaluating the various machining regions
by using quadtree encoding, and pruning the CSG tree accordingly. As a
result, compact CSG trees, each representing a machining region, are
obtained. Analysis shows that the proposed method can successfully
handle cases of feature extraction which are in general difficult to
handle using other methods, particularly the cases of overlapping and
nested features.
|
|
On the design process for customized products and demands upon a technical information system
|
|
E. Agerman / G. Sohlenius (1)
|
|
STC Dn, 40/1/1991, P.161
|
|
Keywords: Customized products, Design |
Abstract : This paper deals with experiences from use of technical information
systems, for design of products tailored to meet customer specifications
and adapted to quality assurance standards like ISO 9000-9004.
Implementation of computer support for calculation and design work had
to follow stringent demands upon a well structured working procedure.
The procedures for the handling of a contract for the design and supply
of such customized products must prevent non-conformity at all stages
from design through to servicing.
The impact of these demands was of crucial importance for the creation
of the Technical Information System.
|
|
Design of software system base on axiomatic design
|
|
S.J. Kim, N.P. Suh (1), S.G. Kim
|
|
STC Dn, 40/1/1991, P.165
|
|
Keywords: Software, Design, Axioms |
Abstract : The ability to utilize the fully automated flexible manufacturing
systems (FMS) or develop a reliable computer-integrated manufacturing
(CIM) system will depend on our ability to develop reliable and reusable
softwares for large complex systems on a timely basis. To date, software
design has not gone beyond the ad hoc trial-and-error stage.
Consequently, the development of software is slow, expensive,
unreliable, and unmanageable. The purpose of this paper is to provide a
scientific basis for designing software. The approach used here is the
axiomatic design, which is based on two design axioms: the Independence
Axiom and the Information Axiom. The axiomatic approach is based on the
recognition of the following common elements in design: the existence of
independent domains (i.e., the consumer domain, the functional domain,
the physical domain, and the process domain): the need to map between
various domains during the design process: the decomposition of the
characteristic vectors (i.e: functional requirements, design parameters,
and process variables) in their respective domains: the zig-zagging
required between the domains for decomposition: and the need to satisfy
the design axioms during the design process. The axiomatic approach
discussed in this paper provides decision making tools for software
design in addition to systematic means of knowledge and data
representation, synthesis and analysis of software, and the construction
of the module-junction structure diagram.
|
|
Discrete part design by taking manufacturing restrictions into account
|
|
F.L.M. Delbressine, J.A.W. Hijink / A.C.H. Van der Wolf (1)
|
|
STC Dn, 40/1/1991, P.171
|
|
Keywords: Design, CAD/CAM |
Abstract : A design methodology has been developed which takes manufacturing
restrictions into account in the design phase. This has been
accomplished by defining manufacturable design transformations. This
paper deals with manufacturable design transformations for a particular
manufacturing technique i.e. milling operations. A typical example is
shown to illustrate this approach.
|
STC E |
|
How to make stereolithography into a practical tool for tool production
|
|
G. Bjorke (1)
|
|
STC E, 40/1/1991, P.175
|
|
Keywords: Stereolithography, Toolmaking |
Abstract : In two large projects BRITE; INSTANCAN and Nordic funds for
technology-industrial development: NORSLA we concentrate on the
development of stereolithography {SLA} into a reliable tool production.
The paper presents the results so far. It covers how to make models
accurate enough, and how to interface SLA to CAD-systems using standard
formals as VDA-FS, IGES, etc., withoutgoing via facets.
|
|
New coating technology for the manufacture of components made from new materials
|
|
P. Hancock / P.A. McKeown (1)
|
|
STC E, 40/1/1991, P.179
|
|
Keywords: Machining, Coating, New Materials |
Abstract : This paper addresses the recent developments in coating technology and
the way in which they can be used to manufacture components made from
the never structural materials. Coatings with properties which can not
be matched by the same material in bulk form are described and their use
as surface coatings for high performance ceramics examined. The
application of new coating technology so the manufacture of components
made by hot isostatic pressing HIP is described and, in particular, the
application to the processing of ceramic fiber reinforced metallic
composites is highlighted.
|
|
Optimization of laser beam transformation hardening by one single parameter
|
|
J. Meijer (2), L. Van Sprang
|
|
STC E, 40/1/1991, P.183
|
|
Keywords: Laser, Hardening, Optimization, Residual Stress |
Abstract : The process of laser beam transformation hardening is principally
controlled by two independent parameters, the absorbed laser power on a
given area and the interaction time. These parameters can be transformed
into two functional parameters: the maximum surface temperature and the
hardening depth.
It has been proven that with a constant hardening depth the results
(hardness, residual stress, etc.) can he optimized easily with respect
to only one independent parameter, the maximum surface temperature,
which is app lied directly in adaptive control strategies.
|
|
Ion beam machining of tungsten carbide chips - fabrication of fine patterns
|
|
I. Miyamoto, A. Shuhara / N. Taniguchi (1)
|
|
STC E, 40/1/1991, P.187
|
|
Keywords: Die, Ion Beam Fabrication, Cemented Tungsten Carbide Chips, Fine Patterns, Mask, Wet Etching, Lift Off, Surface Roughness, Flatness |
Abstract : An ion beam fabrication technique using masks made by wet etching and
lift off methods has been developed to fabricate fine patterns of
several mm in depth and several tens mm in width into a die made of
cemented tungsten carbide chips which is difficult to pattern by
conventional mechanical machining methods, and also by chemical etching,
electro-chemical etching and electro-discharge machining. By choosing
tungsten carbide chios with fine grains of 0.7 mm and optium ion, beam
machining conditions of the work-table being rotated at an ion of 0.1 mm
in Rmax and flatness of under 0.5 mm was obtained.
|
|
Newly developed laser sublimating method for direct formation of conductor film on ceramic substrates
|
|
N. Morita, T. Watanabe, Y. Yoshida / T. Nakagawa (1)
|
|
STC E, 40/1/1991, P.191
|
|
Keywords: Laser Heating, Conductor film, Ceramic Substrate |
Abstract : A new method for direct formation of conductor lines on ceramic
substrates by laser sublimating was developed. This method involves the
selective forming of aluminum thin layers by decomposing aluminum
nitride ceramics in argon gas atmosphere with a Q-switched YAG laser.
This aluminum layers can be employed as a catalyst in electroless
plating. Nickel conductor lines with a specific resistance about 1/10^-7
Wm were directly and selectively deposited on the aluminum layer in
nickel electroless plating solution. This technique will have the high
possibilities to alter, repair and customize circuits in a single and
one-step maskless process.
|
|
A study on laser enhanced plating
|
|
K. Horlo, T. Kasai / A. Kobayashi (1)
|
|
STC E, 40/1/1991, P.195
|
|
Keywords: Physical and Chemical Machining, Laser Enhanced Plating, Electroless Nickel Plating |
Abstract : In this paper, laser enhanced plating, which forms a nickel film on a
metallic substrate selectively with the aid of heat energy by laser
irradiation is studied. A plating solution control system. which
includes solution flow control and temperature control, has been
provided so as to realize continuous plating. The characteristics of
plated nickel films under some experimental conditions have been
investigated. The adhesive strength between a plated film and a
substrate and the strength of a plated film itself have been also evaluated.
|
|
Electrochemical surface finishing of tungsten carbide alloy
|
|
T. Masuzawa (2), M. Kimura
|
|
STC E, 40/1/1991, P.199
|
|
Keywords: Physical and Chemical Machining, ECM, Tungsten Carbide Alloy |
Abstract : This paper deals with an experimental study on finishing the surface of
tungsten carbide alloy. A special design of the/ /pulse train for
alternate polarity ECM is proposed for realizing a uniform dissolution
of tungsten carbine and for suppressing the dissolution of the tool
electrode. The effectiveness was confirmed by applying the pulse on an
EDMed surface. A smooth surface without heat-affected layer or cracks
was obtained. The experiments also led to hints for selecting the
electrode material.
|
|
Development of pocket-size-discharge machine
|
|
T. Higuchi, K. Furutani, Y. Yamagata, L. Takeda / H. Makino (1)
|
|
STC E, 40/1/1991, P.203
|
|
Keywords: Electrical Discharge Machining, Mechanisms, Piezoelectricity |
Abstract : The size of a conventional electro-discharge machine is limited by its
electrode-feeding mechanism which consists of ball screws, gears and
motors. By applying Impact Drive Mechanism (IDM), which can move with
fine step, utilizing rapid deformations of piezoelectric elements, to a
new electrode-feeding mechanism, a pocket-size electro-discharge machine
can be developed, which can be miniaturized to dimensions of 18xl4x68
mm. Its feeding step is variable from 0.02 up to 0.6 mm. The machining
performance for micro holes is as good as that of a conventional
electro-discharge machine. Various applications of the developed
electrode-feeding mechanism are dismissed.
|
|
A new process of finish machining on free surface by EDM methods
|
|
N. Mohri, N. Saito, M. Higashi / N. Kinoshita (1)
|
|
STC E, 40/1/1991, P.207
|
|
Keywords: Electrical Discharge Machining, Finish Machining, Cusp Removal |
Abstract : In this paper, a new process of finish machining on free-form surface is
proposed. This process consists of cutting an electrode and a work by a
machining center, removing cusps of the electrode and the work by EDM
and finish EDM with powder suspended working fluid.
Geometrical tracing of intersections method was used for the generation
of CL data. In cusp removing process after milling by a machining
center, EDM under high wear conditions was carried out. Powder suspended
working fluid was used in finish EDM in order to break through the limit
roughness caused by electrostatic gap capacitance.
Mirror like 3-d surface was realized through a series of automatic
processes by EDM methods.
|
|
A study of the effect of synchronizing ultrasonic vibrations with pulses in EDM
|
|
D. Kremer, C. Lhlaubet, A. Moisan (1)
|
|
STC E, 40/1/1991, P.211
|
|
Keywords: Electrical Discharge Machining, Ultrasonic Vibrations, Synchronization |
Abstract : The paper deals with EDM assisted with ultrasonic vibrations of the
electrode. A first part introduces the beneficial effect of ultrasonic
vibrations: increased feed rate by a better flushing, particularly for
difficult conditions such as finishing with narrow gap; lower damage due
to heating (thinner/ /recast layer, increased fatigue life). This is a
continuation of the paper introduced at CIRP 1989.
A second part shows the results of an experimental investigation of the
technique using a synchronization/ /of ultrasonic vibrations and EDM
pulses. This allows knowing more about the relationship between the
pressure in the bubble and the effect of the discharge. A theoretical
approach is proposed to explain this phenomenon.
|
|
Improvement of EDM efficiency by supplying oxygen gas into gap
|
|
M. Kunieda, S. Furuoya / N. Taniguchi (1)
|
|
STC E, 40/1/1991, P.215
|
|
Keywords: EDM, Oxygen, Stock Removal Rate |
Abstract : This paper describes a new method of EDM which is supplied with oxygen
gas into the discharge gap, when a water dased dielectric is used. It is
found that the stock removal rate is increased due the enlarged volume
of discharged crater and more frequent occurrence of discharge. During
the analysis and discussions, attentions are paid in the heat and force
caused by the activated chemical reactions of oxygen.
|
|
On-Line monitor and control for wire breakage in WEDM
|
|
K.P. Rajurkar, W.M. Wang / R.P. Lindsay (1)
|
|
STC E, 40/1/1991, P.219
|
|
Keywords: Physical and Chemical Machining, Monitoring, Wire-Rupture |
Abstract : Wire breakage (tool failure) is encountered in many industrial
applications (e.g. cutting of complex contours) of Wire Electrical
Discharge Machining (WEDM). This paper describes an on-line WEDM
monitor, and proposes a control strategy to prevent wire rupture. The
monitoring system detects the sparking frequency which is correlated
with the wire breakage phenomena. A large number of sparking frequency
data during the process has been analyzed. Features of the sparking
frequency leading to wire breakage have been identified. The new control
strategy proposes to control the sparking frequency at a constant level
for avoiding wire rupture and improving productivity.
|
STC F |
|
The effect of temperature on the coefficient of friction in flat rolling
|
|
J.G. Lenard / S. Kalpakjian (1)
|
|
STC F, 40/1/1991, P.223
|
|
Keywords: Forming, Hot Rolling, Friction |
Abstract : While it is acknowledged that one of the most important parameters
affecting the magnitude of the coefficient of friction in metal forming
processes is the temperature. Relatively few experimental studies have
bees published that detail their exact relationship. The objective of
the present work is to develop the required data that will allow the
choice of die frictional coefficient to be made with confidence. In the
present study the effect of temperature on the roll separating forces,
roll torques and forward slip are measured during warm and hot rolling
of commercially pure aluminum strips. The magnitude of the coefficient
of friction inferred by matching measured and predicted roil forces. The
results indicate the m is indeed a strong function of the temperature.
In general, increasing the temperature leads to higher values of the
coefficient.
|
|
An interpretation of the speed dependence of the coefficient of friction under the micro-PHL condition in sheet drawing
|
|
A. Azushima, M. Uda, H. Kudo (1)
|
|
STC F, 40/1/1991, P.227
|
|
Keywords: Micro-PHL, Coefficient of Friction, Direct Observation, Sheet Drawing, Tribology, Hydrostatic Pressure |
Abstract : In the previous work, the authors confirmed the occurence of the
so-called micro-hydrodynamic lubrication mechanism using a newly
developed sheet drawing apparatus with a transparent quartz die. In
order to search possibility of this mechanism to reconcile low
friction and smooth surface finish in metal forming operations, the
speed dependence of the coefficient of friction is examined under the
same experimental conditions. The increase in the coefficient of
friction with increasing drawing speed is then interpreted in terms of
the measured volume of the surface pockets trapping lubricant.
|
|
A friction sensor for sheet metal rolling
|
|
C. Nyahumwa, J. Jeswiet (2)
|
|
STC F, 40/1/1991, P.231
|
|
Keywords: Rolling, Interface Forces, Friction |
Abstract : A sensor for measuring interface forces in the roll gap has been
designed. It has been used to measure successfully, the interface
friction forces in the cold rolling of 1100 aluminum. In order to be
sure the friction forces measured at the interface are correct, the
results are integrated across the billet surface and then multiplied by
the torque arm. This quantity is then compared to the input spindle
torque that is measured during the experiment. These results were found
to be within percent of each other for reductions of 20%37; and 25%37;. The
design of the sensor is described and the results are shown for
reductions up to 25%37;, with particular emphasis upon the reductions of
20%37; and 25 %37;. The results are for the unlubricated rolling of 1100 aluminum.
|
|
Modeling the frictional boundary condition in material deformation
|
|
D. Duram, B.F. Von Turkovich (1), A. Assempoor
|
|
STC F, 40/1/1991, P.235
|
|
Keywords: Simulation, Metal Forming, Friction |
Abstract : In the simulation of metal forming processes, the effect of friction at
the boundary between the die and the workpiece presents a complex
analytical problem. Consideration of the area of contact, the contact
loads and the direction of material flow must be adequately handled for
the die/workpiece interface. The present work discusses the development
and use of realistic friction models at the interface which can be
incorporated into the finite element analysis of large scale plasticity.
Particular emphasis is placed upon the transition from sticking to
sliding friction. The concern for the ability of the model to establish
the location and the movement of multiple neutral points in complex
geometries is also addressed, FEM and experimental work was conducted to
evaluate the boundary behavior modeled using the theory of Amontons Law,
the Law of constant Friction and the theory of initial sticking proposed
by Bay, Wanheim et al. It was determined that the initial sticking
theory best approximated the early stage of deformation of the
experimental results.
|
|
Lubrication limits in backward can extrusion
|
|
N. Bay, S. Lassen, K.B. Pedersen, V. Maegaard / T. Wanheim (1)
|
|
STC F, 40/1/1991, P.239
|
|
Keywords: Forming, Cold Pressing, Lubrication |
Abstract : The tribological conditions in backward can extrusion at the contact
between the can wall and the punch land are very severe due to heavy
surface expansion. In the present paper these problems are analyzed
especially at low reduction (r < 50%37;) where they are particularly
pronounced. The influence of degree of reduction, punch nose geometry,
friction and strain hardening of the specimen material on the material
flow is studied by experimental analyses in model material as well as
steel. On the basis of these flow analyses the transition between sound
flow and suction of workpiece material to the punch has 'been estimated
as function of the above mentioned parameters. The local surface
expansion inside the can and the resulting lubricant film distribution
has been measured. The results point out that the punch design normally
recommended is suboptimal at large reductions and inappropriate at small
reductions. A proposal for appropriate punch geometry depending on the
degree of reduction is given.
|
|
Neural networks for process planning of cold forging
|
|
K. Osakada (2), G. Yang
|
|
STC F, 40/1/1991, P.243
|
|
Keywords: Expert Systems, Cold Forming, Pattern Recognition |
Abstract : The technique of neural networks is applied to an expert system for
process planning of cold forging in order to improve the process
generating speed. A three-layer neural network is used and the
back-propagation algorithm is employed to train the network.
By utilizing the ability of pattern recognition of the neural networks,
a system is developed to relate the shapes of rotationally symmetric
products with their preforms and forming methods. Average speed of
process inference for the products which have similar shapes to the
products used in the network training can be improved significantly by
using the trained neural network system.
|
|
Automatic generation of NC Production plans in stamping and laser cutting
|
|
A. Raggenbass, J. Reissner (1)
|
|
STC F, 40/1/1991, P.247
|
|
Keywords: Cutting, Expert System, Tool Loading |
Abstract : Using various stamping and laser cutting machines with a prescribed set
of tools, sheet parts have been manufactured according to CAD drawings.
In this work an expert system will be presented, that generates a
complete NC production plan for stamping, laser cutting or for the
process combination. The module of the system is the geometry processor,
the decision module, the tool selection, the collision module, the
technology processor, the nesting, the path optimization and the
sequence of operations. The main points of the presentation are an
algorithm for tool selection, the formulation and consideration of tool
loading rules, as well as a fast algorithm of path optimization.
|
|
Prediction of cracks in sheet-metal forming with FEM simulations and FLD's
|
|
E. Doege (1), P. Groche
|
|
STC F, 40/1/1991, P.251
|
|
Keywords: crack, FEM, FLD |
Abstract : Forming limit diagrams (FLD's) in connection with calibrated FEM
simulations can serve as a powerful aid towards the prediction of cracks
in sheet metal forming. The critical punch travel has been predicted
with FLD's and FEM simulation with an error of only 3%37;. A prerequisite
for the successful application of FLD's is the separation of deep
drawing and stretching cracks. They differ in the dominating condition
of friction between sheet and tools at the beginning of cracking.
Friction conditions during deep drawing cracks and determined by sliding
friction whereas stretching cracks are accompanied by sticking friction
between sheet and tools.
|
|
Strain path dependence of flow curves
|
|
W.H. Sillekens, J.H. Dautzenberg (2), J.A.G. Kals (1)
|
|
STC F, 40/1/1991, P.255
|
|
Keywords: Forming, Flow Stresses |
Abstract : This paper deals with the changes in flow behavior, resulting from
abrupt changes in the strain path. The transitions
tension-to-compression, tension-to-torsion and torsion-to-tension were
investigated, using the plastic strain at the transition as a parameter.
Three materials were selected for the experiments: CuZn37 brass, C22
steel and Armco steel.
Results of the combined tests are presented and compared with the
corresponding standard flew curves (from compression, tension and
torsion test). A conventional flow function (Hollomon) is accommodated
to record the observed flow curve changes. Metallurgical backgrounds are
considered.
|
|
Mashy-state rolling of aluminium alloys and cast irons
|
|
M. Kiuchi (2), S. Sugiyama
|
|
STC F, 40/1/1991, P.259
|
|
Keywords: Mashy-State, Rolling, Aluminum Alloy, Cast Iron, Functional Sheet, Solid Fraction, Internal Structure |
Abstract : Mechanical and metallurgical features of mashy-state (or mushy-state)
rolling processes are investigated. Mashy-state rolling of aluminum
alloy sheets and cast iron sheets are carried out and effects of rolling
conditions, such as solid fraction (weight percentage of solid
component) of workpiece and thickness reduction, on flow and deformation
characteristics of liquid component and solid component at roll gap
internal structure and mechanical property of rolled sheet are widely
investigated.
The results are as follows. (1) The rolling force decreases
distinctively following to the decrease in solid fraction of workpiece.
(2) When the solid fraction of workpiece is low, the solid and liquid
components flow separately at roll gap. (3) In that case, the internal
structure of rolled sheet differs completely from that obtained by hot
rolling. (4) Mechanical properties of aluminum alloys and cast irons may
he improved and new type of functional sheets of those metals can be
manufactured by the mashy state rolling.
|
|
Microstructural evolution during hot rolling
|
|
A.S. Korhonen (1), A. Rantanen
|
|
STC F, 40/1/1991, P.263
|
|
Keywords: Forming, Hot Rolling, Finite Element Method |
Abstract : Finite element modeling of the hot rolling of steel plates was studied.
The finite element code ABAQUS was complemented by a recrystallization
model called MICROPLA. It appeared that the rolling force as well as the
final grain size and the yield strength of the plate could be predicted
with a fairly good accuracy. To study the accelerated cooling after
rolling, the phase transformations were taken into account approximately
by considering the different cooling rates in the center and at the
edges of the plate. The predicted distortion of the plate was reduced
about tenfold after the phase transformations were taken into account.
|
|
Towards a capability for predicting the formation of defects during bulk deformation processing
|
|
A. Zavallangos, L. Anand (2), B.F. Von Turkovich (1)
|
|
STC F, 40/1/1991, P.267
|
|
Keywords: Forming, Finite Element Method, Defects |
Abstract : A set of constitutive equations for large deformations of isotropic,
thermo-elasto-viscoplastic, microporous materials, and a new
fully-implicit, incrementally objective, fully-thermo-mechanically
coupled, time integration procedure have been incorporated into a finite
element computer program, and the program is used to study the formation
of material related defects (e.g. surface and internal porosity/ damage
shear bands) which may occur in various stages or representative bulk
deformation processing operations.
|
|
Determination of instability in sheet metal based on the anisotropic yield ellipse
|
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J. Danckert / T. Wanheim (1)
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STC F, 40/1/1991, P.273
|
|
Keywords: Sheet Metal, Forming, Plasticity |
Abstract : The paper presents expressions for the subtangents at the onset of
diffuse, respectively local instability in sheet metal. The subtangents
have been determined using definitions of the effective stress and the
effective strain, which in case of uniaxial tension reduce to the true
stress and true elongation strain.
Using this approach, the material's stress-strain curve obtained in a
uniaxial tension test. is directly applicable in the determination of
the curves for diffuse and local instability.
|
|
A finite element analysis of high speed metal forming processes
|
|
J.F. Fontaine, J.C. Gelin (1)
|
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STC F, 40/1/1991, P.277
|
|
Keywords: High Speed Forming, Finite Elements, Viscoplasticity, Rolling, Upsetting |
Abstract : A finite element formulation to deal with the flow of metal that
includes high speed effects is presented. The deformation process of the
metal is treated using the rigid-plastic or the rigid-viscoplastic
approach and the solution technique used includes convective and
acceleration effects in the equilibrium equations of the problem. In the
first part of the paper the mechanical aspects of high speed metal
forming processes are analyzed, then the solution procedures using the
finite element method are developed. An interesting version of the
three-field approach is presented to obtain an accurate solution for the
stress field. Then the last part of the paper presents the results
obtained for the steady state wire-drawing process, the steady state
extrusion problem, the steady state rolling problem and a deep drawing
problem. The results obtained are compared with experimental ones and
with results obtained from the quasi-static case. It is clearly shown
that in some cases of industrial relevance, it is necessary to take into
account of dynamic effects to obtain a good agreement with the experiments.
|
|
Deformation analysis of deep drawing by the finite element method
|
|
H. Darendeliler, B. Kaftanoglu (1)
|
|
STC F, 40/1/1991, P.281
|
|
Keywords: Forming, Deep-Drawing |
Abstract : A Finite element method is developed to study the elastic-plastic
deformation of sheet materials in the presence of large strains and
large displacements. It is based on updated Lagrangian type formulation
and membrane shell theory. The sheet is assumed to be isotropic and rate
insensitive which obeys J_2 flow theory. The work-hardening
characteristics of material and Coulomb friction between the sheet metal
and forming tools are incorporated. The method is used for modeling
partial deep-drawing with the appropriate boundary conditions. Numerical
solutions are compared with the experimental results.
|
|
Process simulation of metal forming processes : some examples
|
|
M. Hermann, M. Wilhelm, p. Keck / K. Lange (1)
|
|
STC F, 40/1/1991, P.285
|
|
Keywords: Forming, Finite Element Method, Process Models |
Abstract : A finite element program for the analysis of axissymmetric and three
dimensional metal forming processes is presented. The underlying
mechanical model is based on an elasto-plastic constitutive law for
isotropic material behavior including work-hardening. Contact problems
at the interface between workpiece and tool are handled by means of
penalty method. The tool is assumed to be rigid. Thermal effects are
negliged.
The paper describes the application of the finite element code EPDAN to
the simulation of different forming operations: upsetting test according
to Rastegaev, rectangular tensile test, axissymmetric bulging pf
thick-wailed tubes (liquid bulge forming) and bending in a V. shape die.
As far as possible the computational results are compared to
experimental data.
|
|
Forming aligned fiber composites into complex shapes
|
|
T. Gutowski, A. Tam, G. Drillon, S. Stoller / N.P. Suh (1)
|
|
STC F, 40/1/1991, P.291
|
|
Keywords: Composites, Forming, Differential Geometry |
Abstract : Differential geometry theory is used to show how an ideal aligned fiber
composite (incompressible, inextensible fibers, constant uniform spacing
between fibers) must be deformed in order to make a part of complex
curvature. Three fundamental results are obtained; the first two relate
the required shears to the fiber curvatures (normal and geodesic), and
the third, called the Gauss-Bonnet theorem, relates the shears to the
Gaussian curvature of the part and the fiber orientation. Finally, it is
shown how these results can be used to simplify experimental data.
|
|
Knowledge based systems and F.E. simulations in metal forming processes design : an integrated approach
|
|
N. Alberti (1), L. Cannizzaro (2), F. Micari (2)
|
|
STC F, 40/1/1991, P.295
|
|
Keywords: Cold Forming, CAPP, Expert Systems |
Abstract : The automatic computer aided planning and design of cold forming
processes includes several phases, among which the most important are
the optimal choice of the forming operations sequence and, for each
operation, the determination of the more suitable operating parameters.
With this aim the Authors propose an integrated approach based or the
preliminary choice of some feasible forming sequences, carried out by
means of a knowledge-based system, and on the subsequent determination
of the optimal one employing a finite element simulation of the process.
|
|
A generalized life-time model for cold extrusion tools
|
|
L. Cser (2), M. Geiger
|
|
STC F, 40/1/1991, P.299
|
|
Keywords: Forming, Extrusion, Tool-Life, Expert System |
Abstract : It is very difficult to predict the expected life time at cold extrusion
because of the complexity of the interchanges among the different kinds
of failures and failure mechanisms. To the prediction of the most
probably life time for a class of cold forming tools an expert system
has been developed which takes into account the geometrical, mechanical
and tribological boundary conditions and utilizes factory data and
experience.
In order to be able to handle the different mechanisms of failure it was
necessary to work out a generalized life-time model of cold forming
dies. The governing idea is similar on the state-space method used in
the qualitative reasoning. All the damage mechanisms are active at the
same time, but the life-time is determined by the dominant mechanism
leading fastest to the total fail out of the dies. The role of the
dominant mechanism can be taken over by other mechanisms during the
exploitation of the die, depending on the changes in the state-variables.
The expert system is based on the feature processing. The tool is
derived into the elements carrying out only geometric information, but
information about the loads and the possible failures also. The elements
of the same tool parts are connected with each other by different type
of contact an neighbors between the elements of different tools part.
|
|
Fracture mechanics analysis of extrusion dies
|
|
M. Geiger / K. Lange (1)
|
|
STC F, 40/1/1991, P.303
|
|
Keywords: Forming, Tool Life, Fracture, Simulation |
Abstract : Premature tool failure caused by fatigue crack growth or wear is a
severe problem to industrial application of metal forming technology.
Better knowledge about manufacturing process, tool loading and fracture
behavior is necessary in order to improve tool design. Process
simulation applying Finite Element Method could offer a powerful
assistance for process-adjusted tool layout. The paper will give some
results of FE-simulation of tool loading and fatigue crack propagation
in extrusion dies and some considerations about tool life prediction. A
new approach to J-controlled fatigue crack growth under complex mixed
mode tool loading will be presented.
|
|
Development of CAE system for auto-body panel forming die design by using 2D and 3D FEM
|
|
A. Makinouchi, E. Nakamachi, T. Nakagawa (1)
|
|
STC F, 40/1/1991, P.307
|
|
Keywords: Sheet Forming, Computer Aided Engineering (CAE), Finite Element Method |
Abstract : An integrated CAE system for auto-body press tool design is discussed.
The CAE system is required to predict forming defects by computer
simulation and to save time and cost needed for tool design. This system
consists of five models. The first module is CAD which describes tool
geometry; the second module is data bases which provide experimental
data; the third module is a pre-processor generating a finite element
mesh in the sheet metal; the forth module is two elasto-plastic FE codes
to simulate sheet metal forming processes; and the last module is the
post-processor which displays the calculated results by computer
graphics. Two elasto-plastic FE cods, ITAS and ROBUST, are introduced in
the FE module. ITAS uses 2-D solid elements to simulate 2-D bending
deformation, while ROBUST employs a membrane model to simulate fully 3-D
sheet metal forming processes.
|
|
Flexible numerically controlled tool system for hydro-mechanical deep drawing
|
|
E. Von Finckenstein (1), M. Kleiner
|
|
STC F, 40/1/1991, P.311
|
|
Keywords: Deep Drawing, Toolmaking, Flexibility |
Abstract : The development of a flexible, numerically controlled tool system for
deep drawing and stretching is described. The tool system, whose idea is
based on Japanese and American researches, consists of a matrix of 1089
rods, which form the deep drawing punch by adjusting each of them
individually. After the workpiece, which is to be manufactured, has been
constructed with a CAD-system, the control data for the tool adjustment
control is generated automatically out of the workpiece geometry by a
special software. The tool system is used with a conventional hydraulic
press, with has an equipment for hydro-mechanical deep drawing.
|
|
A method of blanking from amorphous alloy foils using rubber tool
|
|
F. Takahashi, T. Nishimura, I. Suzuki / H. Kudo (1)
|
|
STC F, 40/1/1991, P.315
|
|
Keywords: Blanking, Amorphous Materials, Foils, Tooling |
Abstract : In the conventional blanking method from amorphous alloy foils, the
clearance between punch and die should be kept extremely small. Since it
is difficult to make such a tool set in the case of large and
complicate-shape products, we developed a novel method of blanking. The
punch was made of rubber instead of steel and a strong counter force was
generated by a rod type spring or by a hydraulic pressure unit. The
relationship was investigated between the product quality and the
process variables, e.g., the counter pressure, punch material and punch
penetration into the die. The present method was found to press-work
acceptable products from amorphous alloy foils and also to be applicable
to blanking of complex-shape products such as motor stator lamination.
|
|
Computer aided wire drawing
|
|
A. Zompi (2), M. Cipparrone, R. Levi (1)
|
|
STC F, 40/1/1991, P.319
|
|
Keywords: Wire, Drawing, Simulation |
Abstract : Current studies on mechanics of cold wire drawing provide a
comprehensive picture, of the effects of main parameters on the basic
process. However at production floor level multipass drawing still
exhibits a number of tough problems. Scatter in wire properties,
defects, lubricant decay, irregular die wear may affect product quality
and upset production schedule. By combining experimental evidence with
theoretical and numerical models of the basic friction and deformation
process into a global description of multipass machine operation, taking
into account stochastic process properties, production planning
procedure may be effectively supported, and reliable guidelines for
process control and trouble shooting are obtained.
|
STC G |
|
Influence of up-grinding and down-grinding on the contact zone
|
|
J.G. Wager (1), D.Y. Gu
|
|
STC G, 40/1/1991, P.323
|
|
Keywords: Grinding, Temperatures, Cutting Forces |
Abstract : The influence of up-grinding and down-grinding on the contact zone has
been compared with respect to six factors: level and distribution of
surface temperature, forces, roughness distribution, occurrence of
visible burn, contact length and relationship of the entry region and
the exit region.
Though a better understanding of the influence of these two modes on the
contact zone, some general influences about the effective difference
between up-grinding and down-grinding are presented in this paper.
|
|
Force and chip formation in single-grit orthogonal cutting with shaped CBN and diamond grains
|
|
Y. Ohbuchi, T. Matsuo (1)
|
|
STC G, 40/1/1991, P.327
|
|
Keywords: Grinding, Micromachining, Superabrasives |
Abstract : Single-grit orthogonal cutting text have been performed on a carbon
steel with shaped CBN and diamond single grain (#20/24). The cutting
test were carried out by means of a reciprocating surface grinder. The
cutting and thrust forces were measured under different cutting
conditions. Chip formation mechanism was also studied. Thus, the effects
of cutting speed and rake angle on the forces or chip formation became
clear for the two abrasive types. The CBN grain was much lower in
cutting forces than the diamond grain, and the forces increased largely
by changing a rake angle from ?45° to ?75°.
|
|
Grinding of transformation toughened Y-TZP ceramics
|
|
R. Krishnamurthy, L.M. Arunachalam, C.V. Gokularathnam / V.C. Venkatesh (1)
|
|
STC G, 40/1/1991, P.331
|
|
Keywords: Transformation Toughening, Grinding, Zirconia |
Abstract : Developments in ceramics have introduced a nee class of ZrO_2 ceramics
called as ceramic steel. By controlling the mol, percentage and particle
size, a Zirconia-Yttria ceramic was developed which exhibits toughening
by tetragonal to monocline transformation. The inserts made of TTZ
(Transformation Toughened Zirconia) were ground for application as a
cutting tool. During surface grinding, toughening of surface material
was observed; the amount of transformation was more with CBN than
diamond grinding, indicating the stress induced nature or
transformation. This transformation has influences significantly
specific grinding pressure, normal grinding force component and surface
quality.
|
|
An attempt to predict residual stresses in grinding of metals with the aid of a new grinding parameter
|
|
B.W. Kruszynski, C.A. Van Luttervelt (1)
|
|
STC G, 40/1/1991, P.335
|
|
Keywords: Residual Stress, Grinding, Surface Integrity |
Abstract : Residual stresses are considered as the most representative parameter of
all properties in the surface layer created by grinding processes and
which allow a relatively good assessment of the performance of ground parts.
The damage caused by the creation of residual stress in the surface
layer of metals has been analyzed from the point of view of the thermal
aspects of the process with the purpose of finding a representative
parameter which combines the most important grinding parameters and
which is strongly connected with the residual stress created in the
surface layer. Such a parameter may be useful when selecting grinding
conditions of critical parts.
The suggestion of such a parameter has been developed. The evidence -
based on analysis of available data found in literature - of its good
functional correlation to the residual stress generated in different
workmaterials in different grinding operations is presented and
discussed in the paper.
It seems that the proposed new grinding parameter may be helpful in a
better control of surface integrity in grinding in the industrial practice.
|
|
An advance in the modelling of thermal effects in the grinding process
|
|
W.B. Rowe (1), M.N. Morgan, D.A. Allanson
|
|
STC G, 40/1/1991, P.339
|
|
Keywords: Machining, Grinding |
Abstract : The proportion of the grinding energy entering the workpiece may be
analyzed either for the whole grinding wheel-workpiece contact zone or
for the average grain contact zone which is two orders of magnitude
smaller. An analysis which does not clearly apply to one zone or the
other introduces conceptual difficulties since the relative speed seen
by the workpiece is very different for the two cases. At the grinding
zone level the workpiece sees a relative speed of Vw whereas at the
grain level the workpiece sees a relative speed of Vs+/- Vw.
An analysis has been presented for partitioning at the grain level which
overcomes these conceptual problems. Result from the new model are
compared with the results from other models.
|
|
Thermal aspects of grinding : the effect of heat generation at the shear planes
|
|
A.S. Lavine / B.F. Von Turkovich (1)
|
|
STC G, 40/1/1991, P.343
|
|
Keywords: Grinding, Temperature, Modeling |
Abstract : The model of heat transfer in the grinding zone which had been
previously developed by the author has been modified to account for the
fact that some of the grinding energy is generated at the shear planes.
Examples are given to evaluate how much error was incurred in making the
earlier simplification that all the heat is generated at the wear flat
areas. For finding with aluminum oxide wheels, it is found that the
error is typically not huge, but may be significant, depending on the
grinding conditions. For grinding with CBN wheels, however, the error is
very important.
|
|
On performance of brazed bonded monolayer diamond grinding wheel
|
|
A.K. Chattopadhyay, L. Chollet, H.E. Hintermann (1)
|
|
STC G, 40/1/1991, P.347
|
|
Keywords: Grinding, Diamond Tools |
Abstract : In recent years, in many applications, brazed bonded single laver
diamond tools are getting preference over galvanically bonded
counterpart because of their outstanding performance. High crystal
exposure is reported to be one of the most distinguished features of the
brazed tool. The present study, however, has revealed that commercially
fabricated brazed tools do not necessarily provide high crystal exposure
as claimed by the manufacturer because of accumulation of bonding
material in the space between the grits during brazing. Performance of
such commercially manufactured wheels, relative to that of brazed tools
fabricated according to CSEM's new process, with improved uniformity of
bond level and grit protrusion, is reported in this paper. Oxide ceramic
and cast iron were used as work materials during grinding experiments.
|
|
Development of chipping-free dicing technology applying electrophoretic deposition of ultrafine abrasives
|
|
J.L. Ikeno, Y. Tani, A. Fukutani / H. Sato (1)
|
|
STC G, 40/1/1991, P.351
|
|
Keywords: Abrasives, Depotion, Brittle Materials, Chipping |
Abstract : It is very important to decrease the amount of chipping in the dicing
process brittle materials for the reduction of material loss and the
improvement of surface integrity in the production of optical and
electrical components. The use of ultrafine abrasives reduces the
grain depth of cut which results in the minimization of subsurface
damage. Thus, a new dicing technology has been developed by applying
electrophoretic deposition of ultrafine abrasives. During the process,
the abrasives cohered around a conductive thin blade used as the anode
in an electric field and polished the side surfaces of grooves.
Consequently, chipping-free dicing was accomplished and an optically
smooth surface was obtained on the side surfaces of the groove.
|
|
A selftuning adaptive control system for grinding processes
|
|
E. Brinksmeier (2), C. Popp
|
|
STC G, 40/1/1991, P.355
|
|
Keywords: Grinding, Adaptive Control, Diagnostic Routines |
Abstract : This paper deals with the development and use of an
adaptative-control-system for the external grinding process. Because the
behavior of the grinding process is substantially influenced by
disturbance a selftuning controller is employed. A system identification
procedure is used in order to allow a permanent adaptation of the
controller to the changing process parameters. The change in the
identified system parameters can also be used to diagnose process faults
such as grinding wheel wear and to compensate for dimensional deviations
due to elastic deformation of the workpiece-tool-machine system.
|
|
Monitoring and optimization of internal grinding process
|
|
I. Inasaki (2)
|
|
STC G, 40/1/1991, P.359
|
|
Keywords: Grinding, Sensors, Tool Life |
Abstract : The grinding process is influenced by many factors such as grinding
wheel characteristics, dressing conditions and, of course, grinding
conditions. Therefore, it is difficult to perform the grinding operation
in an optimum state. In this study, in-process monitoring methods using
power and acoustic emission sensors are proposed to detect malfunctions
in the internal grinding process. In addition, a new internal grinding
cycle featuring rapid infeed is proposed to minimize the grinding cycle
time.
|
|
Development of a simplified electrochemical dressing method with twin electrodes
|
|
K. Suzuki, T. Uematsu, T. Yanase, M. Honma, S. Asano / T. Matsuo (1)
|
|
STC G, 40/1/1991, P.363
|
|
Keywords: Grinding, Electrochemical Dressing |
Abstract : The paper deals with a newly developed method for electrochemical
dressing of metal bonded superabrasive wheels. In this method,
alternating currant, derived from a wall outlet via an inexpensive
transformer is supplied to a wheel through twin electrodes, hence a
troublesome brush and an expensive DC power source are unnecessary. The
process dressing of a wheel (d=200 mm) was accomplished within a few
minutes. Inprocess dressing of a wheel resulted in lower grinding force,
longer wheel life and higher grinding efficiency in grinding of ceramic
materials and hard metals.
|
|
Development of productivity in aspherical precision machining with in-situ metrology
|
|
T. Nishiguchi, Y. Koizumi, Y. Maeda, M. Masuda, K. Nagayama / K. Okamura (1)
|
|
STC G, 40/1/1991, P.367
|
|
Keywords: Aspherical Machining, In-Situ Metrology, Form Error, Tool Setting Error |
Abstract : This paper deals with the development of aspherical machining technology
with in-situ metrology using the stylus method for the purpose of
improving machining accuracy and reducing machining time. This technique
is based on the in-situ measurement of machined geometrical accuracy,
which makes it possible to calculate both the deviation of nominal tool
diameter from the true one and the tool setting error in tool feed and
traverse directions. The machining time can be reduced to a hail, or
one-third with application of this procedure to either aspherical
grinding or diamond turning.
|
STC M |
|
Variable-grain cross-coupling controller for contouring
|
|
Y. Koren (1), C.C. Lo
|
|
STC M, 40/1/1991, P.371
|
|
Keywords: Control System, Controller |
Abstract : The increasing trend for higher precision in manufacturing systems has
brought an increasing interest in the design of servo controller. One of
the most effective methodologies for contouring applications is the
cross-coupling control (CCC). This paper introduces a new CCC method
which utilized variable gains that are adjusted in process according to
the shape of the part. The variable-gain CDC enables a contour error
reduction of 3:1 to 10:1, depending upon the starting point and the
resolution of the system as well as the contour clean.
|
|
Motion control of the direct drive actuator
|
|
H. Makino (1), T. Ohde
|
|
STC M, 40/1/1991, P.375
|
|
Keywords: Machine Tools, Dynamic Control, Actuator |
Abstract : Two methods are adopted for the servo control of the Direct Drive (DD)
actuator: (1) I-PD control for precise positioning with possible load
fluctuations, and (2) P-'D + torque feed forward control for high-tact
repetitious motion of stable load. In both methods, the selection of
input motion curve is important to avoid residual vibration which is
caused by the input signal components and by the output load. From this
point of view, the cam curve control is used. Adjusting the parameters
of the "Universal Cam Curve", several characteristic curves are obtained
and tested for the control of the DD actuator. Experimental results are
shown and discussed.
|
|
Experimental research on the linear motor micro-feed device with high frequency response, long travel and high accuracy
|
|
X.W. Wang, D. Wu / Z.J. Yuan (1)
|
|
STC M, 40/1/1991, P.379
|
|
Keywords: Micro-Feed, Linear Motor, Noncircular Cutting |
Abstract : This pacer deals with the design and experimental research on the
micro-feed device consisting of a linear motor, a laser interferometer
and a high speed processor. Being of a closed-loop precision NC system,
the device works mainly with the linear motor, which produces linear
movement directly and has very fine servocontrol performance. This
system is particularly suitable for a lathe to cut workpieces with
noncircular cross sections.
|
|
Preload-control in ball screws - A new approach for machine tool building ?
|
|
H. Weule (1), H.U. Golz
|
|
STC M, 40/1/1991, P.383
|
|
Keywords: Machine Tool Building, Ball Screw, Preload-Control |
Abstract : The preload in ball screws does not just have positive effects on zero
backlash and rigidity, moreover it increases the friction loss which
leans to heating and wear as well as a reduction of fatigue life of ball
screws. With this background a system is introduced which allows
variable set-up and control of the preload in ball screws. A ring-shaped
piezoelectric translator is used as actuator, the design and
characteristic features of which are described. The improvements
obtained by the principle or preload-control are described by means of
test results. Advantages for the manufacturing processes, such as an
increase in cool life for machining with interrupted cat, are expected
by the possibility of variation of camping and rigidity of the forward feed.
|
|
An advanced robot control system for manufacturing processes
|
|
G. Duelen (1), H. Münch, D. Surdilovic
|
|
STC M, 40/1/1991, P.387
|
|
Keywords: Robotics, Control System, Reference Model, Hybrid Position/Force Control, Contact Tasks |
Abstract : Presented in this paper is an advanced robot control system which is
used as a research and test environment. Its hierarchical and highly
modularized structure, based on a new standard reference model proposed
for telerobot control system architectures, allows customized
development and implementation of different complex advanced control
concepts and algorithms, including fusion of multisensor data.
An overall system-oriented approach for sensor-driven manufacturing
processes with industrial robots was developed and tested. A contact
task was used to demonstrate the system performance.
|
|
Adaptive force control for robotic disk grinding
|
|
M.A. Elbestawi (2), K.M. Yuen, H. Dai, A.K. Srivastava
|
|
STC M, 40/1/1991, P.391
|
|
Keywords: Robots, Grinding, Adaptive Predictive Control, Force Control, Parametric Modeling |
Abstract : In this paper, the design and implementation of an adaptive predictive
force controller for robotic grinding are described. The force
regulation is established by modifying, on-line, the robot's programmed
position control commands. The experiments were conducted using an
industrial robot equipped with a pneumatic grinder and a six degrees of
freedom force sensor. Two predictive control laws, namely; Generalized
Predictive Control (GO), and Extended Horizon Control (EH) are evaluated
by simulation and experimentally. The control laws are designed based on
accurate model(s) for the open-loop dynamics of the robot and grinding
process, which are identified from experimental data.
The results show that both controllers are able to effectively regulate
the normal grinding force and compensate for force errors caused by step
force disturbances and robot path tracking errors. A slightly better
control performance was achieved, however, using the Generalized
Predictive Controller.
|
|
Assessment of accuracy of robots in relation with geometrical tolerances in robot links
|
|
R. Weill (1), B. Shani
|
|
STC M, 40/1/1991, P.395
|
|
Keywords: Machines, Robots, Accuracy |
Abstract : Absolute accuracy of robots has been plaguing designers of industrial
robots since the beginning of the robot era. Several models of robot
errors have been developed recently, but non is considering all types of
errors occurring in he links and joints of robots. Therefore, a new
model raking in account all errors of position and orientation at the
end effector as a function of the geometrical errors in the links was
developed. A graphical program enables a colored mapping of the errors
in the whole workspace of the robot for typical nets of errors in the
links. The relation between the error parameters in the model and the
standardized definition of geometrical tolerances is established.
|
|
A predictive monitoring and diagnosis system for manufacturing
|
|
S. Spiewak / M. Szafarczyk (1)
|
|
STC M, 40/1/1991, P.401
|
|
Keywords: Machines, Predictive Maintenance, Microprocessors |
Abstract : A systematic approach to the monitoring and diagnosis of machine tools
and manufacturing processes is presented. This approach leads to a
design methodology and a generic system structure for shop-floor
applications. The essential components of this structure are discussed.
Selected results obtained during several years of research illustrate
crucial elements of the methodology. A modular and expandable system,
whose design is based on the proposed methodology, is presented. This
system, developed for a large car manufacturing company, has a hybrid
structure composed of a traditional computer and a distributed parallel
processing network.
|
|
Evaluating the cutting performance of machining centers
|
|
J. Tlusty (1), S. Smith, C. Zamudio
|
|
STC M, 40/1/1991, P.405
|
|
Keywords: Cutting, Machining Centers, Testing |
Abstract : The paper discusses the theoretical background for Cutting Performance
testing in a new ASME draft standard dealing with chatter and with
effects of cutting force on workpiece accuracy. The most important
measures for assuring that results be significant for comparative
assessment and repetitive are the choice of tools and of the cutting
speed. The tools arc so chosen as to generate "spindle modes" and not
"tool modes". The spindle speeds are so chosen as to be above the range
of "process damping" and below the range of significant "stability lobing".
|
|
Optimization of large composite structures
|
|
M. Weck (1), T. Nottebaum
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STC M, 40/1/1991, P.411
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Keywords: Design, Optimization, Fiberglass Reinforced Plastics |
Abstract : The determination of optimal designs of large composite structures is a
problem of high complexity and suggests the use of structural
optimization methods. This paper presents a software system which
applies numerical optimization algorithms to the design of large
multilayer composites with respect to weight and displacement
minimization. Design variables are lamina angles and thicknesses. For
structural and sensitivity analysis the finite element method is used.
The system is integrated into a CAE environment for ease of practical
application. An example is given to show the performance of the
presented system.
|
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Machining high precision mirrors using newley developed CNC machine
|
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K. Ueda, A. Amano, K. Ogawa, H. Takamatsu, S. Sakuta, S. Mural, A. Kobayashi (1)
|
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STC M, 40/1/1991, P.555
|
|
Keywords: Diamond Turning, Grinding, Machine Tool, Form Accuracy |
Abstract : An ultra precision CSC machine was developed for manufacturing high
precision mirrors. The machine is capable of machining aspheric mirrors
up to 650 mm in diameter and 250 mm in axial length. Laser
interferometer feedback systems, with 2.5 nm resolution, are
incorporated in both X and Z slide notions. Using this machine, a
concave mirror, made from an electroless nickel plated aluminum
material, was finished by diamond turning. The mirror had a form
accuracy of less than 0.1 ?m P-V and 2 nm Ra surface roughness.
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An active air journal bearing with ultra precision, infinite static stiffness, high damping capability and new functions
|
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A. Shimokohbe, O. Horikawa, K. Sato / H. Sato (1)
|
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STC M, 40/1/1991, P.563
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|
Keywords: Air Bearing, Stiffness, Damping, Active Control, Piezoelectric Actuator, Positioning |
Abstract : The aim of the paper is to develop an Active Air Journal Bearing (AAJB).
AAKB is a rotary air bearing of a controlled type following features:
(1) ultra precision, (2), infinite static stiffness, (3) high vibration
damping capability, (4) new functions such as the positioning of the
rotating axis and the dynamic stiffness control. Such features are
realized by positioning the axis with an active bearing (AAB). AAB is
composed of a static air bearing mechanism, a non-contact sensor, a
piezoelectric actuator, a controller and an objective mass to be
controlled, i.e. the axis. Then the compliance and the axis positioning
characteristics are examined. Finally, the radial position of the axis
rotating at 1000rpm is controlled and the rotation accuracy of the axis
less than 25 nm is accomplished.
|
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Feed servo control for ultra-precision turning machine
|
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J.T. Li, X.C. Xu, B.L. Zhang (2)
|
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STC M, 40/1/1991, P.567
|
|
Keywords: Feed Servo Control, Ultra Precision, Turning Machine |
Abstract : This paper describes the high precision servo system and its
mathematical model for the CNC ultra-precision turning machine which was
developed by Beijing Machine Tool Research Institute (BMTRI ). With feed
forward and variable gain control, back force compensation, mechatronic
servo system can be simplified. The system provides 0.01 ?m resolution,
500 kpps travel frequency and 0.25µm positioning accuracy within 200 mm
(X), 0.4 µm within 400 mm (Z).
|
STC O |
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Criteria for optimum layout design of assembly systems
|
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C.R. Boër (2), J. El-Chaar, E. Imperio, A. Aval
|
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STC O, 40/1/1991, P.415
|
|
Keywords: Optimization, Assembly Lines, Simulation |
Abstract : The performance and the return of investment for Assembly Systems are
very much dependent on the throuput of the system, on the utilization of
the more important components (robots, AGVS, etc.) and on the reusing of
these components in different configurations. The paper deals with the
criteria for optimum layout design and how simulation is used to
validate the criteria.
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Operational dimension and tolerancing in CAPP
|
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H.C. Zhang, J. Mei, R.A. Dudek / F.W. Boulger (1)
|
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STC O, 40/1/1991, P.419
|
|
Keywords: CAPP, Automated Tolerancing, Operational Dimensioning and Tolerancing Chain |
Abstract : The ideal output of operational sequencing of CAPP should include all
start and end coordinates of tool movement for all operational
dimensions rather than just give dimensions and tolerances unrelated to
the coordinate system on the NC machine and leave additional work for
the NC programmers. This paper deals with a new method of analysis of
Operational Dimension and Tolerance Chain (ODTC) for CAPP systems. Based
on discussion of previous works, apparent shortcomings are discussed and
an extended approach provides ODTC to generate operational dimensions
and tolerance for NC machines as a part of the decision methodology of
CAPP systems.
|
|
Development of integrated process planning and monitoring system for turning operation
|
|
K.K. Cho (2), S.H. Lee, J.H. Ahn
|
|
STC O, 40/1/1991, P.423
|
|
Keywords: CAPP, Process Monitoring, Database, Knowledge-Based System |
Abstract : This paper deals with the development of a prototype system which
integrates process planning interfaced with CAD system and process
monitoring for CNC turning operation through the interface and
integration of data and knowledge processing. The integrated system is
aimed for small and medium-sized machinery industry, and AutoCAD and
CLIPS which can be run on personal computer are used as a CAD system and
an exert system shell for knowledge-based process planning,
respectively. The test results to show the system performance indicate
that this prototype system works well for turning operation.
|
|
Structured modelling of manufacturing processes as NC-Data preparation
|
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W. Eversheim (1), G. Marczinski, R. Cremer
|
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STC O, 40/1/1991, P.429
|
|
Keywords: Process Planning, NC-Programming, CAD, CAPP, Information Modelling, STEP |
Abstract : Process planning is a crucial link in the development of an integrated
production environment. As information technology is a key for such an
integration the modeling of manufacturing processes assumes a
particularly important role.
The present paper reveals a concept of modeling manufacturing processes
for NC-programming applications. Today?s situation concerning CAPP and
NC-data generation in view of CIM is analyzed. Requirements for the
integrated modeling are derived. The concept for manufacturing process
modeling is described, showing the close relation of functional and
information modeling. Neutral interface aspects are covered by referring
to the STEP-standard.
|
|
Optimization of set-up strategies for operating automated SMT assembly lines
|
|
K. Feldmann, N. Roth (2) / K.G. Günther (1)
|
|
STC O, 40/1/1991, P.433
|
|
Keywords: Optimization, Flexible Assembly, Surface Mount Technology, Set-up Strategies |
Abstract : The state of the art in automation of he assembly of printed circuit
boards (PCB's) is very advanced. But since the solutions realized up to
now are mainly concentrated on the existing spectrum of standard
components the introduction of the new technology of surface mounted
devices (SMD) requires new approaches. The end time for a defined
production volume of PCB's with SMD is decisive influenced by the choice
of the set-up status of the assembly systems or assembly lines invoiced.
The paper describes an approach to minimize the lead time by developing
an optimization strategy for the initial set-up and subsequent chances
in set-op of the components.
|
|
A new concept of CAPP based on flair of experienced engineers. Analyses of decision making processes of experimenced process engineers
|
|
T. Ihara, Y. Ito (2)
|
|
STC O, 40/1/1991, P.437
|
|
Keywords: Flair-Based CAPP, Experienced Process Engineer, Priority Rule |
Abstract : in Decision-Making, Eye-Mark Camera Test, Model Pattern-Oriented
Knowledge Base
In using CAPP of knowledge-based type of the present, the required time
for producing the process plan increases with the amount of the
accumulated knowledge to be process. In contrast, process planning by
the experienced engineer does not take so much time, and it appears to
be in inverse proportion to tha amount of knowledge so far accumulated
by this long experience. This paper describes some representative
results of the questionnaire investigation on the priority rule in
decision-making of the experienced engineer, after choosing the
axi-symmetrical parts as objectives. Following it, an eye-mark camera
test is carried out to ascertain the validity of the questionnaire
investigation. Comparing these both the results along with those of
non-experienced engineers, the essential features of decision-making are
furthermore explicated. Based on the evidences obtained, a new concept
of CAPP of flair-based type, i.e. that with model pattern-oriented
knowledge base, is amso proposed in the present paper, and a part of it
is actually produced.
|
|
A flexible real-time adaptive control system for turning
|
|
T. Lundholm / B. Lindström (1)
|
|
STC O, 40/1/1991, P.441
|
|
Keywords: Optimization, Turning, Adaptive Control |
Abstract : The paper deals with the organization of a new adaptive control system
for turning and an integration framework for subsystems in the adaptive
control system. Different monitoring, adaptive control constraint and
adaptive control optimization functions are assigned to five
subsystems. Monitoring and control of machining operations is based on
measurements of machining characteristics and the subsystems induce a
number of advanced sensor systems which are briefly descried. The
stochastic nature of the machining process calls for real -time control
of machining conditions. The subsystems are designed to operate in a
relatively independent manner. Consequently, computer technologies for
real-time and distributed control have been employed to realize a
flexible modular system architecture for the adaptive control system.
The layout of the system as well as the adaptive feedrate control
strategy are presented.
|
|
A system approach for decision making in production grinding
|
|
S. Venk / E. Merchant (1)
|
|
STC O, 40/1/1991, P.445
|
|
Keywords: Optimization, Decision Making, Grinding |
Abstract : A model of a potential Information Management Scheme to aid intelligent
decision making for Production Grinding (IMSPG) is being proposed here.
Its complete realization is a long term goal and involves implementation
of the PBS (Prolog Based System), PCPlus, and grinding cycle modules of
the proposed IMSPG model. Each module employs a unique approach for
decision making related to its problem area. Actual industrial case
studies are presented to illustrate the approach and working of the
selected modules. Overall, industries implementing this model can be
expected to realize significant benefits due to enhanced competitive
decision making.
|
|
Semantic techniques for representation and identification of part families
|
|
G. Perotti (1), S. Tornincasa, G. Oberto
|
|
STC O, 40/1/1991, P.451
|
|
Keywords: Group Technology, Cluster Analysis, Feature-Based Models |
Abstract : The paper deals with the automatic feature recognition of workpieces and
families formation. To generate part families, the used approach
utilizes a frame based representation system both for data and for features.
A clustering method is used to take into account the morphology, the
dimensions as well as the manufacturing sequences of parts. Being the
procedure a self learning one, the introduction of new parts into the
families is relatively simple.
|
|
5-axis control machining and grinding based on solid model
|
|
Y. Takeuchi, T. Idemura / T. Sata (1)
|
|
STC O, 40/1/1991, P.455
|
|
Keywords: Cutting, Grinding, 5-Axix Control |
Abstract : The study deals with 5-axis control machining and grinding of workpieces
with sculptured surface line impellers. The 5-axis control machining and
grinding allows complex workpieces to be produced efficiently and
accurately. Then, it is of importance to avoid the collision between
tool and workpiece due to the arbitrariness of tool attitude. The system
developed in the study generates the collision-free tool path for
machining and grinding workpieces with sculptured surface, based on the
CAD/CAM system employing the solid modeling technique. As a result, the
validity of the system is experimentally confirmed.
|
|
A computer support system for manufacturing based on discrete event models
|
|
H.E. Islo, G. Sohlenius (1)
|
|
STC O, 40/1/1991, P.459
|
|
Keywords: Interactive design systems, Computerized Simulation, Human Factors Engineering |
Abstract : This paper deals with the specification and implementation of a
comprehensive computer support system to be used for the design and
operation of manufacturing systems. Models of manufacturing systems
which demonstrate requisite variety are considered to be the vital
component of the computer support system. Therefore, we concentrate on
the properties and characteristics which these models should embody.
Among the advantages of this approach is the possibility to include
human factors into the model and thus into the computer support system
itself. Another is the possibility to use the models in an evolution
strategy for optimization of system parameters.
|
|
Product life cycle economic models
|
|
V.A. Tipnis (2)
|
|
STC O, 40/1/1991, P.463
|
|
Keywords: Optimization, Life Cycle of Product and Process, Economic Models, Environmental Impact, Competitive Strategies, Concurrent Engineering, Penalty Costs |
Abstract : A quest for a comprehensive life cycle economic model has been launched,
prompted by the need to know the cost of making products and processes
environmentally safe as well as the need to evaluate alternate product
and process designs before the first production run is made. Classical
manufacturing cost models, cost and management accounting models, and
microeconomic models are not adequate. Recently introduced micro- and
macro- economic models of manufacturing processes provide cut and
sequence level analysis. The constraint (bottleneck) model demonstrates
the importance of bottlenecks for minimizing throughput time. Activity
Based Costing is a welcome development from accounting discipline.
Significant progress has been made in determining the penalty cost when
products and processes fail in field and in production. The real
challenge is to develop the model in such a manner that it becomes a
valuable tool for designing products and processes robust, competitive,
and environmentally safe to operate, dispose and recycle.
|
|
Optimization of production flow patterns by use of intelligent CAD tools
|
|
A. Villa (2), C. Bandera
|
|
STC O, 40/1/1991, P.467
|
|
Keywords: Process Planning, CAD |
Abstract : Optimization of production flow patterns results from scheduling the
working activities to be performed by all Machining Centers (MCP) for
processing all required parts. The complexity of this problem is
prohibitive for obtaining a practically implementable solution. A
decomposition-based approach is therefore highly recommendable. This
paper presents a solution based on decomposition of the whole activity
scheduling problems into a set of interconnected sub-problems, one for
each part family. Since a part family cannot be processed
"individually", i.e. on a proper cell, interactions among above
mentioned sub-problems exist. The paper proposes a knowledge-based
procedure using CAD tools, suitable for managing interactions and aimed
at obtaining the best separation of sub-problems. An application of the
intelligent CAD tool to a small-scale plant is also presented.
|
|
Communication and mapping systems for a free ranging automated guided vehicle
|
|
Z. Katz, J. Asbury / R. Weill (1)
|
|
STC O, 40/1/1991, P.471
|
|
Keywords: mapping |
Abstract : The conceptual design and specific needs for a free-ranging AGV are
presented. The work focuses on the physical development of such a unit
with particular emphasis on communication between the off-board computer
and on-board microprocessor for control and operation of the vehicle,
A mapping system in real time for the potential path requirements is
developed. Criteria for optimization and continuous path determination
are tested. Simulation procedures are discussed.
|
|
Logistic analysis of production processes by operating curves
|
|
H.P. Wiendahl (1), T. Kuprat
|
|
STC O, 40/1/1991, P.475
|
|
Keywords: Operating Curves, Funnel Model, Throughput Diagram, Plant Layout |
Abstract : In view of their logistic objectives, production control and plant
layout are faced with an apparently insoluble conflict between short
lead times and low work in progress on the one hand, and high capacity
loading and due date performance on the other. The following paper slows
that this opposing dependence is capable of representation and, above
all, of quantification by operating curves. By resort to operating
curves, the practitioner may evaluate the situation of production in
real-life operational cases. To the theorist, these operating curves
offer a universal method for modeling and evaluation of manufacturing
processes.
|
|
Real time model reference adaptive control of 3D sculptured surface machining
|
|
K. Yamazaki (2), N. Kojima, T. Saito, C. Sakamoto
|
|
STC O, 40/1/1991, P.479
|
|
Keywords: Optimization, Adaptive Control, Sculptured Surface Machining, CAD/CAM, Geometry |
Abstract : The paper deals with a new method for the productive machining of molds
and dies which have an artistic geometry characterized by sculptured
surfaces. The method developed is referred to as a 'Real Time Model
Reference Adaptive Control' which autonomously adjusts the optimal
feedrate such that the material removal should always be maximized with
respect to the capability of a given tool and a given geometry of a
workpiece by using a real time simulation of a software-based cutting
process model. The practical feasibility of the proposed scheme has been
verified through experiments performed on the prototyped system.
|
|
Non-contact 3D digitizing and machining system for free-form surfaces
|
|
K. Saito, T. Miyoshi / H. Yoshikawa (1)
|
|
STC O, 40/1/1991, P.483
|
|
Keywords: 3D, free-form |
Abstract : A 3-D digitizing and machining system with a non-contact displacement
sensor is introduced in this paper. This system consists of an NC
milling machine, a personal computer to convert geometric model data
into the NC driving data and a non-contact digitizing sensor for a
free-form surface,
This sensor, with a measuring range of 20 mm and resolution of 11
?m/pixel, can measure the displacement of the free-form surface within
an accuracy of ±50 ?m for a steep inclined surface up to ±75 degrees.
The system can not only measure, but also machine the free-form surface
such as 3-D model shapes for injection mold and pattern.
|
|
Sensor aided programming and movement adaptation for robot guided deburring of castings
|
|
G. Seliger, L.H. Hsieh / G. Spur (1)
|
|
STC O, 40/1/1991, P.487
|
|
Keywords: Cutting, Deburring and Cast Cleaning, Sensor Guided Robots, Sensorial Burr Detection, Process Modelling |
Abstract : Automatically identifying burrs and planning robot trajectories for
respective castings, geometrical and technological adaptation parallel
to the process are tasks to be solved for flexible deburring automaton.
Conditions of access and collision as well as different technologies
e.g. milling, grinding or brushing must be considered for process
design. A universal process model based on a frame concept with
homogeneous transformation matrices has been applied for implementation
or a microcomputer thus coupling robot control and sensorial devices.
The paper describes a prototypical realization of deburring operations
in a robot cell. Evaluation criteria for different technological
approaches are given.
|
STC P |
|
The processing of measured points in coordinates metrology in agreement with the definition of standardized specifications
|
|
A. Ballu, p. Bourdet (1), L. Mathieu (2)
|
|
STC P, 40/1/1991, P.491
|
|
Keywords: Dimensional Metrology, Coordinate Measuring Machines, Measurement Standards |
Abstract : Increasingly, coordinate measurement techniques are used to ensure that
mechanical parts conform to their geometric specifications. The analysis
of the possibilities of the software in use brought to light an
important number of tools, which however are not always adapted to the
problem which is to be solved. Generally these tools only give one
approximate answer to the problem set out by the verification of the
dimensional and geometrical specifications.
An indept study of the standards lead to the presentation, in this
paper, of the problem typology, the two aspects of the verification of
the specifications (measurement and control) will be presented and also
the implication which these have on the solution algorithms. Finally, an
attempt to define new processes giving the true value of the size to be
verified is proposed. These proposals will he illustrated by an example
and the numerical results will be analyzed and compared.
|
|
On the composite position tolerance for patterns of holes
|
|
E.A. Lehtihet, N.U. Gunasena / A. Clément (1)
|
|
STC P, 40/1/1991, P.495
|
|
Keywords: Composite Position Tolerance, Coordinate Measurement Techniques, Simulation of Production Errors, MMC/RFS Comparative Evaluation |
Abstract : The verification of Composite Position Tolerances for patterns of holes
was formulated as a non-linear optimization problem and a fast algorithm
based on the method of feasible directions was developed for
implementation on Coordinate Measuring Machines. The performance of the
algorithm was tested and a simulation of composite position tolerance
production was carried out. The influence of set-up errors, tool
position errors, number of holes in the pattern and material condition
specifications on the probability of producing a mod pattern were simulated.
|
|
Algorithm for the combined approximation of continously differentiable profiles composed of straight lines and circle segments
|
|
G. Goch / H.J. Renker (1)
|
|
STC P, 40/1/1991, P.499
|
|
Keywords: Coordinate Measuring Machines (CMM), Approximation, Deviation-Function |
Abstract : A lot of workpieces and tools are manufactured by using copying turning
machines. Many of them have profiles composed of straight lines and
circle segments. Due to an number of reasons the profiles of the
corresponding master workpieces or templates sometimes have to be
changed slightly, specially the templates for forming tools (e.g.
stamping dies for the manufacturing of ball bearings). In order to
determine the actual geometry of a template (e.g. for a change of
manufacturing to CNC-turning machines) the profile must be measured and
approximated by a new profile consisting of straight lines and circle
segments, which is continuously differentiable in its whole domain of
definition. This paper describes an algorithm for the approximation of
any profile composed of straight lines and circle segments in one step,
i.e. the whole curve is not approximated sequentially segment by segment
but in one iteration run thereby fulfilling the chosen norm in the
complete domain. Approximation according to both the L_2 -norm and
T-norm is possible and the profile is continuously differentiable at
the joints between segments (excepted "edges" in the original profile).
Basic mathematics will be briefly discussed and results obtained by
measurements will be given.
|
|
Positioning accuracy of drilled holes
|
|
J. Kaminski, R. Crafoord / N. Martensson / (1)
|
|
STC P, 40/1/1991, P.503
|
|
Keywords: Drilling, Hole Position, Accuracy |
Abstract : When selecting hole machining sequences, demands on positional accuracy
determines the first drilling operation. The cutting data during the
first revolution of the drill mainly determines the statistical
deviation of hole position. The initial cutting process, when a drill
approaches a workpiece, determines the lateral displacement of the drill
and thus to a great extent the final position of the hole. With existing
buckling theories, the deflection of the drill is partly explained. An
experimental study of initial drill forces and positional deviations of
holes, has given additional information on the influence of drill
stability, surface inclination and quality, resulting in rules for a
generative expert system for planning of operation sequences for hole
machining.
|
|
Non-contact optical probe with holographic optical element
|
|
B.H. Zhuang, K.Q. Lu, J.H. Zhang, X.J. Wang, Z. Li / G.X. Zhang (1)
|
|
STC P, 40/1/1991, P.507
|
|
Keywords: Precision, Non-Contact Optical Probe, Holographic Optical Element (HOE) |
Abstract : A smart non-contact optical displacement probe in which Holographic
Optical Element (HOE) plays a major role is proposed. A HOE is basically
a hologram which is a diffraction element recorded in a thin film. In
this paper, the equation of the interference fringe patters of HOE is
derived. The patterns of a CGH master are written by e-beam lithography
with a resolution reduced ten times. The HOEs are duplicated as 5 mm in
diameter. Several technique problems, such as double holo-knife-edge
method, aspheric objective lens design and non-linearity correction are
discussed. The experimental results are presented.
|
|
The resolution of positioning solids
|
|
A. Clement (1)
|
|
STC P, 40/1/1991, P.511
|
|
Keywords: Metrology, Resolution, Solid |
Abstract : The paper deals with the generalization of the concept of the resolution
of positioning. The study permits the calculation of positioning a solid
at any point and any direction in space, given the resolution of the
scale of the coordinate system, or the quality of the guidance system.
Some practical examples will be presented.
|
|
Lenght bar and step-gauge calibration using a laser measurement system with a coordinate measuring machine
|
|
P.S. Lingard, M.E. Purss, C.M. Sona, E.G. Thwaite (1)
|
|
STC P, 40/1/1991, P.515
|
|
Keywords: Dimensional Metrology, Coordinate Measuring Machine, Laser Interferometer, Length Bar Calibration, Step-Gauge |
Abstract : The most precise CMMs do not have the accuracy required to perform
calibrations on length-bars and step-gauges except by recourse to
conventional comparison techniques. This paper describes an economical
method for substantially upgrading the single-axis measurement accuracy
of a precision CMM using a laser interferometer. The measurement suits
presented demonstrate that the system provides a practical and effective
method to calibrate length-bars and step-gauges. The uncertainty of
measurement derived from the analysis of errors conforms to OIML order
of accuracy class 4 requirements.
|
|
A method for machine geometry calibration using 1D ball array
|
|
G.X. Zhang (1), Y.F. Zang
|
|
STC P, 40/1/1991, P.519
|
|
Keywords: Dimensional Measurement, Calibration, Coordinate Measuring Machine |
Abstract : A method of machine geometry calibration using 1-D ball array is
presented. A series of balls are equal spared fixed on a rigid bar. The
spacings between balls are calibrated by a special laser interferometer.
The position of the balls is sensed by a magnetic socket or a 3-D
non-contact capacitive probe. The distinct feature of the hall array is
that it gives 3-D positioning errors of the CMM simultaneously. It can
be used for measuring all 21 source errors and for error compensation of
CMM. The straightness errors are measured by using reversal method. The
angular error notions are determined by measuring the displacement or
straightness errors of two parallel lines. The squareness errors are
determined by using the diagonal method. The 1-D ball array has low
cost, high efficiency and high accuracy. It is expected to find wide
applications in machine calibration and error compensation.
|
|
Development of a coordinate measuring system with tracking laser-interferometers
|
|
O. Nakamura, M. Goto, K. Toyoda, Y. Tanimura, T. Kurosawa / K. Uehara (1)
|
|
STC P, 40/1/1991, P.523
|
|
Keywords: tracking, laser-interferometers, measuring system |
Abstract : A highly accurate co-ordinate measuring system for a large measurement
area (larger than 1mx1m) is developed. The system consists of two
target-tracking stations, each with a laser interferometer and a twin
cube-corner mirror attached to a target. Since the co-ordinate of the
target is computed from the radial distances between the target and the
rotation axes of the tracking stations, the system can give
position-measuring accuracy better than 1 µm , regardless of the
absolute distances involved. Experimental comparisons between the system
developed and a commercial co-ordinate measuring machine show that the
position measuring accuracy of the developed system is better than 1.0
µm in a plane that is 600-800 mm away from the tracking stations.
|
|
Uncertainties in the acquisition and utilization of coordinate frames in manufacturing systems
|
|
Y.L. Shen, N.A. Duffle (2)
|
|
STC P, 40/1/1991, P.527
|
|
Keywords: Quality, Computer Integrated Manufacturing, Uncertainty |
Abstract : Accurate and consistent transformations between design and manufacturing
coordinate frames are essential for precision part production. These
coordinate transformations establish surface position and orientation
relationships as manufactured parts pass from design trough production
processes to inspection and surface error analysis. Unfortunately, these
coordinate transformations can be uncertain due to factors such as
geometric form errors in workpiece reference surfaces, fixture locating
point variations and coordinate measurement errors. A method for
representing and estimating these uncertainties and their propagation
through multi-stage manufacturing processes is presented in this paper.
The method is applicable to systems with combinations of fixturing and
coordinate measurements.
|
|
Elimination of geometrical errors by permutations - Application to a rotary table
|
|
T. Coorevits, J. David / P. Bourdet (1)
|
|
STC P, 40/1/1991, P.531
|
|
Keywords: Calibration of Rotary Table, Coordinate Measuring Machine, Reference Objet |
Abstract : Errors elimination of a standard using sign change is a well-known
method in order to define lacks of straightness or squareness of a
measuring machine. The paper presents how it is possible to eliminate
geometrical errors even on complex standards (with some symmetry
conditions) by using a permutation technique. The method is presented
from a mathematical point of view and is then applied to the analysis of
two different rotary tables.
|
|
Cryogenic diamond turning of stainless steel
|
|
C. Evans / J.B. Bryan (1)
|
|
STC P, 40/1/1991, P.571
|
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Keywords: Precision Engineering, Diamond Turning, Steel |
Abstract : Tool wear is extremely rapid when ferrous materials are single point
diamond turned. This paper reviews diamond tool wear mechanisms, showing
that both fracture and chemical mechanisms may be important. The rate of
all chemical reactions increases exponentially with temperature. Hence
tool wear may be reduced significantly by machining at cryogenic
temperatures, A cryogenic machining system comprising tool post and
chuck with constrained liquid nitrogen flows has been built. Using this
system a number of 35 mm diameter, 400 series stainless steel flats have
been diamond turned. Surface finish is better than 25 nm Ra.
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STC S |
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Determination of residual stresses in multi-materials, multi-layers pieces. Adaptation to ceramic coatings
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M. Laracine, C. Bignon, M. Lormand, A.B. Vannes, C. Bedrin (2)
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STC S, 40/1/1991, P.535
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Keywords: Surfaces, Residual Stresses, Ceramics Materials |
Abstract : The production of multi-lavers multi-materials coatings requires the
knowledge of their mechanical behavior, and specially of the internal
residual stresses fields.
The method based on layers removal has been previously explained, for
metallic pieces, the more usual removing mode is E.C.M. We have extended
this model to the case of multi-materials coatings. Nevertheless, for
ceramics materials (not electrical conductors), we had to use special
cutting tools, after having verified that this process did not disturb
significantly the considered stress field. We have thus analyzed various
industrial samples, and explained the results with the blocks method.
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Surface characterization and defects detection by analysis of images obtained with coherent light
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P.M. Lonardo (2), A.A. Bruzzone, C. Gambaro, F. Parizzi
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STC S, 40/1/1991, P.541
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Keywords: Surfaces, Optical Measurement, Diffraction |
Abstract : The paper presents a new approach to surface characterization by means
of digital image analysis. The images, obtained through the diffraction
of a concentrated beam of coherent light, exploring the surface, are the
Fourier transform of the surface roughness.
The features extracted from the images depend on the surface typology
and local defects. The experimental work is a contribution to the
development of surface quality control systems without direct contact.
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Performance studies of uncoated, CVD coated and PVD coated carbides in turning and milling
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V.C. Venkatesh (1), C. Ye, D.T. Quinto, D.E.P. Hoy
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STC S, 40/1/1991, P.545
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Keywords: Surface Integrity, PVD and CVD Coatings, Turning and Milling |
Abstract : In turning, the three types of inserts initially produced workpiece
surface finish of almost equivalent roughness but the CVD tool effected
the brightest (maximum gloss) surface. In milling also the CVD tool gave
the brightest surface. Specular reflectance is enhanced by the cutting
edge profile which differs for turning and for milling. An image
processing technique was developed which is able to distinguish very
slight differences in surface gloss. Optical microscopy revealed
irregular thermal cracks in CVD coatings but none in the PVD coatings.
In turning the crack networks became elongated into comb cracks which
protected the crater area. These observations can be rationalized in
terms of high residual compressive stress in PVD coatings, desirable in
milling wear mechanisms, as opposed to low tensile residual stress in
CVD coatings. Cutting forces with PVD were also lower, and the secondary
shear zone thinner, than with CVD tools.
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