CIRP ANNALS 2001
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STC A |
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Internet based Diagnosis of Assembly Systems
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K. Feldmann (1), J. Göhringer
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STC A, 50/1/2001, P.5
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Keywords: Diagnostics, Knowledge based system, Assembly |
Abstract : A high availability is of particular importance for modern
assembly systems to ensure the return of the high investment costs. Due
to the complexity of the occurring failures and the world-wide use of
the systems the manufacturer must provide a global service. Therefore an
internetbased diagnosis system was developed, which can be used both for
local and for remote diagnosis. The system provides different programs
for visualisation and failure diagnosis. These are based on a central
knowledge data base that contains all relevant information.
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Micro Handling with Rotational Needle-type Tools under Real Time Observation
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M. Nakao, K. Tsuchiya, K. Matsumoto, Y. Hatamura (1)
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STC A, 50/1/2001, P.9
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Keywords: Micro, Assembly, Handling, Tool |
Abstract : This paper analyzes human operation of an arbitrary single
micro object under 1mm while observing the object and systematically
studies the design of a micro handling system to perform such
operations. This system features the following mechanical elements; (1)
a needle-type tool with a tip as small as the micro object to handle;
(2) a palette engraved with micro structures to hold the micro object;
(3) a driving mechanism not only to translate the tool but also to
rotate it; (4) a microscope to observe the tool operation in real time.
As the microscope occupies a large volume, the system sets the mechanism
elements in a centralized arrangement so the micro object, tool tip,
center of tool rotation, microscope focus intersect at one point and the
remaining elements are radially arranged around it. We used this system
to conduct several operations including a SEM monitored micro house
construction by assembling and bonding walls and roof, an optical
microscope monitored microscopic insemination by inserting a sperm into
an ovum, and a fluorescent microscope monitored DNA surgery cutting out
an arbitrary gene from a chromosome. These operations verified the
effect of the above design guideline, that is the group of mechanism
elements and their construction.
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On-line control of robotized Gas Metal Arc Welding
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M. Lanzetta, M. Santochi (1), G. Tantussi
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STC A, 50/1/2001, P.13
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Keywords: Welding, On-line control, Image analysis |
Abstract : On-line control of welding and soldering is a strategic issue
for the complete automation of robotized plants. The proposed control
system aims to detect the most critical defects in industrial
applications. It is based on the analysis of images coming from two
cameras installed on the welding torch: the arc and the pool observation
allow monitoring the welding process; a laser stripe is used for the
weld bead inspection. The image analysis algorithms developed are based
on the extraction of features, which have been selected after a long
series of experiments. In addition to pre-processing, different filters
have been implemented to increase the system reliability, for the high
noise in images. A basic control system is also addressed. The system
has been tested in weld overlay cladding.
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Integrated Computer Aided Design for Assembly Systems
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C.R. Boër (1), P. Pedrazzoli, M. Sacco, R. Rinaldi, G. De Pascale, A. Avai
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STC A, 50/1/2001, P.17
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Keywords: CAAP, Computer Aided Assembly Planning |
Abstract : Assembly being the last step of the production cycle of a
product, it is normally submitted to the constraints of the precedent
step. Techniques like Design for Assembly have been developed to try to
take into consideration the peculiarities of the assembly process and
reduce costs. The paper present the research and development of an
integrated computer aided design for assembly system. The project main
aim is to obtain methodologies and tools to design and manage a complete
flexible assembly system but in this paper we will describe a CAAP
(Computer Aided Assembly Planning) for the determination of gripping
features, gripper and finger configuration, assembly sequence,
simulation of the assembly system for the design of management rules,
three dimensional simulation of robots (serial and parallel) for the
design of each single assembly and control cell. The results of the
project is tested in a specifically designed and implemented system for
the assembly of electro-mechanical components.
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Hybrid Automatic-manual Assembly Systems
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T. K. Lien / F.O. Rasch (1)
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STC A, 50/1/2001, P.21
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Keywords: Assembly, Flexibility, Productivity |
Abstract : Hybrid assembly systems consist of an automatic assembly
section that feeds a manual finishing line. They are competitive for
medium volume assembly of products with standard basic structures and
many variants that require manual finishing. This paper describes two
basic principles for the manual assembly: The parallel arrangement of
stations, and the sequential arrangement. A theoretical model for the
possible output as function of production volume, number of assembly
operations, number of product variants, and station operation time
imbalance is presented. This model enables prediction of the performance
and selection of the optimal system for a given set of conditions.
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Reduction of Systematic Dosing Inaccuracies During the Application of Highly Viscous Substances
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G. Reinhart (2), J. Gartner
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STC A, 50/1/2001, P.1
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Keywords: Automated sealing application, Process accuracy, Assembly |
Abstract : The automated application of adhesives and sealants on
three-dimensional components requires that the application profile
produced by constant medium dosing along the processing line has to be
as uniform as possible in order to ensure adhesive and sealing
functions. Incorrect dosing occurs especially frequently during the
dosing of highly viscous substances at application points with a high
degree of curvature and these inaccuracies later affect the function of
the component. Incorrect dosing occurs partly due to the way in which
the speed of the handling system responds. For this reason, we have
developed a means of compensating for dosing errors arising from the
kinematic response of the handling machine by methods of calculated
control predictions for the dosing unit based on internal control
information.
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STC C |
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Generalized Modeling of Mechanics and Dynamics of Milling Cutters
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Y. Altintas (1), S. Engin
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STC C, 50/1/2001, P.25
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Keywords: Milling, force, chatter |
Abstract : This paper presents a generalized mathematical model of most
helical end mills and inserted cutters used in industry. The end mill
geometry is modeled by wrapping the helical flutes around a parametric
envelope of a cutter body. The edge geometry for inserted cutter is
defined in the local coordinate system of each insert, and placed and
oriented on the cutter body using cutter's global coordinate system. The
coordinates of a cutting edge are mathematically expressed for both
cases. The chip thickness at each cutting point is evaluated by using
the true kinematics of milling including the structural vibrations of
both cutter and workpiece. By integrating the process along each cutting
edge or tooth, which are in contact with the workpiece, the cutting
forces, vibrations, dimensional surface finish, and chatter stability
lobes for arbitrary end mills and inserted cutters are predicted. The
predicted and measured cutting forces, surface roughness and stability
lobes for helical tapered ball, bull nosed end mills and inserted
cutters are provided to illustrate the viability of the proposed
generalized end mill analysis. The algorithms are integrated to an
advanced cutting process simulation program which is used for process
planning of milling operations to avoid chatter vibrations, torque and
power limit constraints, and dimensional form errors.
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On modelling the influence of thermo-mechanical behavior in chip formation during hard turning of 100Cr6 bearing steel
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G. Poulachon, A. Moisan (1), I.S. Jawahir (1)
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STC C, 50/1/2001, P.31
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Keywords: Hard turning, Work hardening, Thermal softening |
Abstract : This paper deals with turning of hardened alloy steels (up to
HV800). First, the research focuses on the evaluation of flow stress in
machining of 100Cr6 (AISI 52100) bearing steel. A material constitutive
law including work hardening, thermal softening, and strain-rate
sensitivity has been looked for. The work hardening effect has been
determined with the help of quasi-static compression tests performed on
standard test specimens. The dynamic compression tests performed at
"high strain-rates" using the Hopkinson bars, have shown no tendency to
viscosity effects. Hot compression tests show that thermal softening
plays a significant role in the the process feasibility. Cutting tests
performed under various cutting conditions have highlighted the
conflicting work hardening?thermal softening processes. This balance is
discussed with a shear instability criterion, presenting the work
hardening to thermal softening ratio through a revised material behavior
law.
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Temperature on Flank Face of Cutting Tool in High Speed Milling
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T. Ueda (2), A. Hosokawa , K. Oda, K. Yamada
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STC C, 50/1/2001, P.37
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Keywords: End milling, Temperature, Measurement |
Abstract : The temperature on the flank face of a cutting tool in high
speed milling is measured using a two-color pyrometer with a
chalcogenide optical fiber. This pyrometer has a flat response for a
pulse signal of 400 kHz, which is rapid enough to measure the
temperature of an end milling cutter rotating at 10000rpm. The influence
of cutting speed, feed speed, depth of cut on the cutting temperature at
the flank face of a cemented carbide insert is investigated. The
temperature of the end milling cutter rises rapidly with increase of
cutting speed and it is approximately 770 °C at 628 m/min. The heating
and cooling characteristics of the cutting tool are examined and the
temperature change during an intermittent cutting operation is
approximately 150 °C at cutting speed 471 m/min and feed 0.047mm/tooth.
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A model for calculation of the geometrical shape of the cutting tool - work piece interface
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T. Carlsson,T. Stjernstoft / B. Lindström (1)
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STC C, 50/1/2001, P.41
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Keywords: Tool - workpiece interface, turning, computerised simulation |
Abstract : In order to estimate the tool condition, cutting forces,
surface roughness and other variables of interest in turning, it is
important to understand the physical conditions at the cutting tool ?
workpiece interface. The basic parameters in this context are the
parameters which describe the geometrical shape of the tool ? workpiece
interface, i.e. the chip area and the length of the active cutting edge.
For common tools there exist standard formulas for these parameters.
However, when using more exotic cutting angles or non-standard tools
such as a rotating tool insert, the standard formulas do not comply.
This paper presents a general model based on matrix algebra for
calculation of the shape of the chip area and the length of the active
cutting edge and how it can be applied for a rotating tool insert. The
model input is the shapes of the cutting tool and the workpiece, the
cutting data such as feed and depth of cut and the cutting angles
(approach angle, minor cutting edge angle, inclination angle, rake
angle, wedge angle, etc.). The output is the shape of the chip area and
the length of the active cutting edge and their variations with changes
in input parameters.
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An Investigation of the Thermal Effects in Orthogonal Cutting Associated with Multilayer Coatings
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W. Grzesik / C.A. van Luttervelt (1)
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STC C, 50/1/2001, P.53
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Keywords: Cutting, Tool coating, Thermal Analysis |
Abstract : This paper deals with an experimental and analytical
investigation into the tool-chip interface behaviour, influencing the
temperature and heat transfer at the multilayered coated-tool rake face
during orthogonal cutting of carbon and stainless steels. New
methodology for assessing the amount of thermal energy generated when
machining with a coated tool insert with natural and restricted contact
coupled with a metallic chip, using thermophysical properties of the
sliding materials is developed in this study. It was proven, based on
the heat flux analysis, that the use of advanced coatings with an
intermediate Al2O3 layer can substantially improve the heat flow into
the chip at distinctly lower temperatures than other commercially
available coatings. The data obtained can be used for the optimization
of tool selection with respect to friction and heat transfer and for
maintaining the recommended contact temperature.
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Micro-Cutting of Steel to Meet New Requirements in Miniaturization
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H. Weule (1), V. Hüntrup, H. Tritschler
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STC C, 50/1/2001, P.61
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Keywords: Micro-Cutting, Steel, Process Optimization |
Abstract : Due to its hardness, single crystal diamond is the preferred
tool material for micro-cutting. As diamond has a very high affinity to
iron, micro-cutting is mostly limited to the machining of non-ferrous
materials like brass, aluminum, copper or electroless nickel. The
particular material properties of steel make it a very important
material for extending the field of micro-technology applications. This
paper discusses the prerequisites for the micro-cutting of steel using
tungsten carbide tools and the interaction between the properties of the
materials and the process parameters on the manufacturing result.
Further fields of research are identified. The possibilities of this
approach are exemplified on microstructured molds.
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Cutting Load Capacity of End Mills with Complex Geometry
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J.A. Nemes, S. Asamoah-Attiah, E. Budak / L. Kops (1)
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STC C, 50/1/2001, P.65
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Keywords: Milling, Cutter, Failure |
Abstract : Cutting load capacity of cemented carbide end mills with high
length-to-diameter ratios is determined from critical geometric and
loading parameters, including a stress concentration factor (SCF) to
account for serrated edges, which is determined by finite element
analysis. Tensile strengths are characterised using a statistical
Weibull analysis from 4-point bend tests of cemented carbide blanks of
two different diameters. The approach is used to predict probability of
survival for cutters under different loading conditions. Results are
compared to measured failure cutting loads under service conditions as
well as to those measured in static three point bend tests.
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Geometric Generating Mechanism of Machined Surface by Ball-nosed End Milling
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Y. Mizugaki, M. Hao, K. Kikkawa
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STC C, 50/1/2001, P.69
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Keywords: Ball end milling, Machined surface simulation, Kinematic cutter coordination. |
Abstract : This paper presents a new geometric estimation method of
machined surface by ball-nosed end milling in sphere contouring. Firstly
the geometric relationship between a cutting edge and a normal vector of
the sphere has been formulated. Through the equation analysis,
multi-crossing of them up to three times and the zigzag movement of the
cutting edge have been found newly. Also the interference by a major
flank was found too. Secondly a numerical calculation solver was
developed by Newton-Raphson method. Thirdly the graphical display was
realized by a CAD system. Through the observation of machined surfaces,
the interference area was confirmed.
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Material Aspects of Chip Formation in HSC Machining
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H. Schulz (1), E. Abele, A. Sahm
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STC C, 50/1/2001, P.45
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Keywords: Chip formation, High speed cutting, Cutting forces |
Abstract : Investigations in the past have shown that chip formation
changes by increasing cutting speed, because most of the experimental
work had been carried out in the original material stage. In contrary to
this new machining investigations were made on an aluminum alloy at
different heat treatment states. These investigations confirm that
precipitation hardening is the key in changing from continuous to
segmented chip formation and not only the cutting parameters. By
applying this new knowledge, the relationship between chip formation and
cutting forces was examined.
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Testing and Design of Tool Coatings with Properties Adapted to the Use of Biodegradable Cutting Fluids
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F. Klocke (1), T. Krieg, E. Lugscheider, K. Bobzin
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STC C, 50/1/2001, P.57
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Keywords: Cutting, Coating, Tribology |
Abstract : The paper focuses on defining demands on tool coatings
developed for use with biodegradable cutting fluids, presenting new
coating systems and research results on necessary coating
functionalities which match these technological demands. Coating
development and a tribological test scheme for the realisation of high
tribooxidation stability is also described. The scope for improving the
anti-adhesive properties of coatings for drilling tools are outlined.
This covers the physical characterisation of surface polarity and
surface energy of PVD hard coatings and the behaviour of nano-layered
WC/C-coatings in the drilling of austenitic stainless steel.
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Chip Formation in Machining Ti6Al4V at Extremely High Cutting Speeds
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A. Gente, H.-W. Hoffmeister / C.J. Evans (1)
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STC C, 50/1/2001, P.49
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Keywords: chip formation, titanium, specific energy |
Abstract : The chip formation of Ti6Al4V is described in the cutting
speed range between 300 m/min and 6000 m/min. The specific cutting
forces are measured. A new quick stop method is introduced which allows
rapid decelaration from 2500 m/min in a very short distance, providing
new information on the formation of segmented chips. The conditions at
the onset of segmentation are described. A change in the structure of
segmentation is observed with a cutting speed exceeding 2000 m/min.
However, no change in specific cutting energy coincides with this change
in structure.
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STC Dn |
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Creation of Freeform Solid Models in Virtual Reality
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M.C. Leu (2), B.Y. Maiteh, D. Blackmore, L. Fu
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STC Dn, 50/1/2001, P.73
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Keywords: virtual, design, modeling |
Abstract : A novel method has been developed using a virtual reality (VR)
environment to create solid models with freeform surfaces. The VR
environment emulates the physical environment for creating freeform
objects, i.e. the freeform model is created in a virtual environment by
shaping a virtual workpiece with a variety of virtual tools. The
trajectories of the virtual tools are generated by the designer?s hand
movements and they are obtained by recording the position and
orientation of the motion tracker mounted on a device held by the hand.
A haptic device can be worn by the designer to provide a feel of the
model creation process. In the mathematical algorithm, the swept volumes
of the design tools are computed from the tools? geometric data and
trajectories. Boolean operations are then performed on the swept volumes
of the virtual tools and the virtual workpiece to create the design
model. If the virtual tools used have the same geometry as the real
tools used in numerically controlled (NC) machining, their trajectories
in the model creation process can be postprocessed and used as feasible
trajectories in actual NC machining to fabricate the design model.
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Tele-Design for Manufacturing
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A. Fischer (2), J. Barhak
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STC Dn, 50/1/2001, P.77
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Keywords: Reverse engineering, Surface reconstruction, Rapid prototyping |
Abstract : One of the main challenges in manufacturing today is to reduce
the time cycle for designing and prototyping new products.
Tele-designing for manufacturing systems will make it possible to
integrate distributed processes into one unified continuous
manufacturing process. Tele-engineering is based on two merged
technologies: Reverse Engineering (RE) and Rapid Prototyping (RP). These
technologies together form an interactive and collaborative distributed
system that transfers, models and analyzes scaled 3D models in real
time. However, the current state of the art in these technologies does
not provide a complete telemanufacturing system. This paper surveys
these RE and RP technologies and outlines their pros and cons with
respect to tele-engineering. Then, it proposes a reconstruction method
based on a Neural Network (NN) technique that improves the
tele-engineering process. Finally, the paper discusses expected future
advancements, including the extension of the proposed Neural Network
method and its impact in the near future on tele-engineering.
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Haptic Interaction with Non-rigid Materials for Assembly and Dissassembly in Product Development
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F.-L. Krause (1), J. Neumann
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STC Dn, 50/1/2001, P.81
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Keywords: virtual, tactile sense, deformation |
Abstract : The subject of the present research activities include an
innovative system for haptic support of handling simulations of flexible
parts. The objective of this project is to develop a virtual environment
from dedicated methods of one or two handed touching, pressing, pulling,
gripping or handling of virtual tools, workpieces or other components.
In the current stage of development, highly qualitative interactions
such as gripping and the precise movement of flexible objects are being
supported. These tests are carried out in order to achieve statements
about the ability to assemble or disassemble a product. A PDM Enabler
interface provides the link between the system and a PDM database. Using
this coordinated approach, optimal integration of the solution within
the process chain of product development is ensured.
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Integrated Design Method to Improve Producibility based on Product Key Characteristics and Assembly Sequences
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L. Mathieu (2), B. Marguet
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STC Dn, 50/1/2001, P.85
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Keywords: Assembly sequencing, Integrated design, Tolerancing analysis |
Abstract : Producibility improvement is a major challenge for design and
manufacturing firms. For aircraft or car body, this improvement has to
go through a better product assemblability. In order to reach this goal,
effects of manufacturing variations have to be managed. Two questions
are asked about variation reduction: how to control effect of variations
on functional requirements and what product characteristics are most
sensitive to variations. No global answers exist to these questions.
Therefore, we propose to describe in this paper an industrial method.
The main idea of this method is that geometrical variation flows belong
to the assembly process. During the preliminary design, the first step
of our method is to identify where are the Key Characteristics for the
product. The second step of the method performs a qualitative product
analysis in order to eliminate the worst assembly sequences. At last a
quantitative analysis allows to select the most promising assembly
sequences. This integrated method has been applied with success to
aircraft assembly.
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Product Modularization for Parts Reuse in Inverse Manufacturing
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F. Kimura (1), S. Kato, T. Hata, T. Masuda
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STC Dn, 50/1/2001, P.89
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Keywords: Product design, Module structure, Product life cycle |
Abstract : For reducing environmental burden of industrial products, it
is mandatory to rationalize product design and to achieve a closed loop
product life cycle by use of comprehensive parts reuse and recycling. It
is difficult to introduce parts reuse based on conventional product
structure, and appropriate product modularization is necessary to
efficiently manage a closed loop product life cycle. A new product
modularization strategy is proposed across a family of products and
successive generation of products, based on product functionality,
product commonality and life cycle similarity. Car air-conditioners are
examined for the validity of the proposed method.
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Design by Quality Product Digitization
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W. ElMaraghy (2), C. Rolls
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STC Dn, 50/1/2001, P.93
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Keywords: Design, Laser Scanning, Reverse Engineering |
Abstract : The use of reverse engineering in product design has markedly
increased recently. The ability to accurately combine CMM and laser
scanning data, and hence realize the potential benefits of both, is
impaired by a number of uncertainties inherent to each digitization
process. In order to ensure the quality of the digitized data, and
accurate representation of the designer?s intent, it is a pre-requisite
to assess the measurements uncertainties and their sources, and to
develop compensation methodologies. This paper discusses an approach for
evaluating and compensating errors, primarily due to view registration.
Hence the measurements are made as accurate as possible by design.
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Economic Impacts during Microelectronics Product Design
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Z. Wang, W.A. Knight (2)
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STC Dn, 50/1/2001, P.97
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Keywords: Product Design, Integrated Circuit Manufacturing, Cost Estimating |
Abstract : An integral part of product design for manufacture is the use
of predictive cost models to quantify the effects of early design
decisions. An investigation has been performed to develop a set of
detailed cost models to estimate the economic impact of microelectronics
integrated circuit (IC) design alternatives. Cost-of-Ownership models,
developed for IC fabrication equipment, are extended to the various cost
domains in the microelectronics development cycle, including optical
lithography and design for test solutions. The developed cost models
have been implemented in software tools and these utilised to assess the
effects of various design and processing options on overall IC
manufacturing costs.
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Analysis of Remanufacturer Waste Streams Across Product Sectors
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J. Williams, L.H. Shu / R.G. Fenton (1)
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STC Dn, 50/1/2001, P.101
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Keywords: Design, Environment, Remanufacturing |
Abstract : Remanufacture involves the production-batch disassembly,
cleaning, repair or replacement of parts, and reassembly of products for
reuse. Parts that cannot be reused by the remanufacturer enter the waste
stream, examination of which reveals insights about remanufacture
difficulties. Extending beyond our previous study of automotive
products, the remanufacturer waste streams of electrical motors, toner
cartridges, valves and telephones were analysed to support product
design that facilitates remanufacture. The results of this research are
presented in a format that allows a designer to determine the relevance
of the products studied to products being designed.
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Product Models for Life-Cycle
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D. Brissaud, S. Tichkiewitch (1)
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STC Dn, 50/1/2001, P.105
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Keywords: Design, Life cycle, Product model |
Abstract : The product design, manufacturing, assembly and usage
processes have to be globally optimised for the competitiveness of the
enterprises. The contribution of the paper deals with the product models
able to support the views of life cycle engineers to consider those
engineers as design actors in a whole product development cycle. Our
approach is based on the capitalisation and analysis of quality
discrepancies happening in product life cycle. The models themselves and
the necessary information feedback are focused.
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Axiomatic Design of Machine Control System
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K.D. Lee, N.P. Suh (1), J-H. Oh
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STC Dn, 50/1/2001, P.109
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Keywords: Machine Control System, Axiomatic Design, Chemical-Mechanical Polishing |
Abstract : Machine control system development typically relies on the
developer?s experience and trial-and-error. This ad hoc approach can
undermine the very success of the system development, with a lengthy and
costly development period and, possibly, an endless cycle of upgrade and
maintenance. The resulting system also lacks the interchangeability and
reusability. This paper presents the framework based on Axiomatic Design
for the systematic design and implementation of machine control systems.
It structures a complex control system and guides the design and
development of its subcomponents. Various levels of system design issues
are addressed in this structural approach. Based on the methodology
presented in this paper, a control system for an industrial scale
Chemical-Mechanical Polishing (CMP) machine has been developed.
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Integrating Altshuller's development laws for technical systems into the design process
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D. Cavallucci / R.D. Weill (1)
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STC Dn, 50/1/2001, P.115
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Keywords: Design process, Artificial Intelligence, TRIZ |
Abstract : Over several decades, a considerable number of researchers
have performed analyses in order to predict technical systems evolution.
These analyses are issued mostly from historic, situational observations
and results of their works end up often by the formalization of
evolution logic?s based on thorough synthesis. In the framework offered
by TRIZ1, an advanced analysis of these laws have been performed and the
objective of this article is first to introduce these laws and to
propose an operative application framework in order to analyse their
impact in the design process.
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STC E |
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High Precision Finish Cutting by Dry WEDM
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M. Kunieda (2), C. Furudate
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STC E, 50/1/2001, P.121
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Keywords: WEDM, dielectric, Finish cutting, Dry process |
Abstract : This paper describes the development of a new dry wire
electrical discharge machining (dry-WEDM) method, which is conducted in
a gas atmosphere without using dielectric liquid to improve the accuracy
of finish cutting. In dry-WEDM, the vibration of the wire electrode is
minute due to the negligibly small process reaction force. In addition,
as the gap distance is narrower than that in conventional WEDM using
dielectric liquid, and there is no corrosion of the workpiece, high
accuracy in finish cutting can be realized in dry-WEDM. However, some
drawbacks of dry-WEDM include lower material removal rate compared to
conventional WEDM and streaks are more likely to be generated over the
finished surface. Increasing the wire winding speed and decreasing the
actual depth of cut are effective to resolve these drawbacks.
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ECDM (Electro Chemical Discharge Machining), a New Method for Trueing and Dressing of Metal Bonded Diamond Grinding Tools
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M. Schöpf, I. Beltrami, M. Boccadoro, D. Kramer / B. Schumacher (1)
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STC E, 50/1/2001, P.125
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Keywords: Grinding, Electro-chemical dressing, Electrical discharge machining |
Abstract : Metal bonded grinding tools cannot be processed efficiently
and economically by means of traditional conditioning technologies and
are therefore rarely used. A new hybrid technology that combines EDM and
ECM, called ECDM, allows both the trueing and dressing of these grinding
tools in just one step. Therefore ECDM is the ideal technology for
trueing and dressing of metal bonded diamond tools and hence for the
grinding of new cutting materials (Cermets, Ceramics, PCD). This new
method has been applied successfully on a centerless grinding machine.
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Failure of Rapid Prototype Molds during Injection Molding
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J.S. Colton, J. Crawford, G. Pham, V. Rodet / K.K. Wang (1)
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STC E, 50/1/2001, P.129
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Keywords: rapid prototyping, injection mold, failure |
Abstract : Stereolithography rapid tooling materials (typically
epoxy-based photopolymers) show great promise for injection molding of
limited numbers of parts, greatly reducing the time to product. Yet,
they present challenges to designers because of their strength, thermal
characteristics, and shorter lifetimes as compared to other mold
materials. This paper presents models of the forces generated during the
injection molding cycle so as to evaluate the suitability of rapid
tools. The models comprise thermal and mechanical loading during
injection, cooling shrinkage, and ejection. The effects of process
conditions on material properties are studied. Experimental results are
presented.
|
|
Influence of Nd:YAG Parameters on the Selective Laser Sintering of Metallic Powders
|
|
R. Glardon, N. Karapatis, V. Romano / G. N. Levy (1)
|
|
STC E, 50/1/2001, P.133
|
|
Keywords: Nd:YAG laser, sintering, metals |
Abstract : Compared with CW CO2 laser sources, Nd:YAG lasers with
Q-switching capability offer a wider parameter range, with improved
sintering control, due to the short pulsed energy delivery. In
particular, thermal diffusion being strictly limited by the nanosecond
interaction between the energy pulse and the powder, higher accuracy can
be achieved, while caking can be minimized. By systematically varying
average power, scan velocity and repetition rate, process maps are
established, for various materials, such as nickel and cobalt alloys,
and titanium. Sintering depth and macrostructures are determined for
different parameter sets. Basic models and physical explanations are
given, for the various phenomena and consolidation processes. This
mapping provides a correlation between the process parameters and the
structure and properties of the produced parts. Results show that
roughness and density are related to the pulsed energy delivery. For
example, it is shown that multi-layer Ti samples can be sintered to a
density close to 80 %37;.
|
|
Modeling, Monitoring and Control in High Quality Laser Cutting
|
|
R. Poprawe / W. König (1)
|
|
STC E, 50/1/2001, P.137
|
|
Keywords: Laser, Cutting, Surface Quality, Monitoring |
Abstract : Electrical discharge machining (EDM) and laser cutting are
thermal separation processes widely used in shaping and contour cutting
applications. However, there are gaps in understanding the dynamics of
the process, especially issues related to cut quality. This work
describes the advances in fundamental physical modeling and process
monitoring of laser cutting, as well as time varying processes such as
contour cutting. The onset of evaporation and the increase of capillary
forces are the two physical phenomena relevant to the build-up of
adherent dross. The dynamic model predicts a modulation frequency for
the laser power that leads to almost complete suppression of adherent
dross in contour cutting.
|
|
Micro-bending of Thin Spring by Laser Forming and Spark Forming
|
|
M. Otsu, T. Wada, K. Osakada (1)
|
|
STC E, 50/1/2001, P.141
|
|
Keywords: Microform, Laser, Spark, Bending |
Abstract : To attain accurate bending of thin plate springs, spark
forming in which a plate is bent by thermal stress due to electric spark
is proposed. Experiments are performed with plate springs of 50mm or
70mm thickness made of beryllium copper, pure titanium, pure copper and
18Cr-8Ni stainless steel, and the results are compared with those of
laser forming. The bending angle can be controlled with an accuracy of
1?10-4 degree by the proposed method. It is concluded that spark forming
has advantages in the variety of applicable materials, efficiency of
energy, cost and space of apparatus over laser forming.
|
|
Hybrid High Speed Machining (HSM): System Design and Experimental Results for Grinding / HSM and EDM / HSM
|
|
D.K. Aspinwall, R.C. Dewes, J.M. Burrows, M.A. Paul / B.J. Davies (1)
|
|
STC E, 50/1/2001, P.145
|
|
Keywords: Machining, grinding, electrical discharge machining (EDM) |
Abstract : Point grinding and electrical discharge machining (EDM) are
detailed on high speed machining centres. A Taguchi design was employed
to evaluate operating parameters when point grinding (plunge)
nickel-based superalloys with 15 mm diameter electroplated diamond and
cubic boron nitride (CBN) wheels using speeds up to 60,000 rpm provided
by an ancillary spindle. Material removal of up to 120 cm3 and roughness
values down to 1.2 mm Ra were obtained when machining Inconel 718. A
retrofit EDM servo head unit was designed for die sinking and workpiece
surface texturing. When texturing 2D and 3D workpieces, surfaces were
produced with an Ra of 1-10 mm, depending on operating parameters.
|
|
Design and Characterisation of Ultrasonic Cutting Tools
|
|
M. Lucas, J.N. Petzing, A. Cardoni, L.J. Smith / J.A. McGeough (1)
|
|
STC E, 50/1/2001, P.149
|
|
Keywords: Ultrasonic cutting, Tool design, Vibration |
Abstract : Cutting of food products and other materials with
ultrasonically assisted tools has demonstrated significant benefits
including reduced wastage and improved cut quality. However, the success
of the technology relies on careful design of the ultrasonically excited
tools and transmission components. In this paper, the different
challenges of tool design are discussed with reference to two cutting
devices. The studies demonstrate that accurate characterisation of the
vibration behaviour of the tool and an understanding of the effects and
limitations on vibration responses of design modifications, allows tool
performance to be enhanced in the design.
|
STC F |
|
Enhancing performances of SHPB for determination of flow curves
|
|
P. F. Bariani (1), G. Berti, S. Corazza
|
|
STC F, 50/1/2001, P.153
|
|
Keywords: compression test, high strain rate, flow stress |
Abstract : A compression test on a Split Hopkinson Pressure Bar (SHPB) is
the most common testing method adopted to determine material flow curves
in a quite wide range of high strain rates. However, in most ordinary
SHPB applications material rheology can only be investigated up to a
rather low strain. Furthermore, several phenomena, including friction at
interfaces and radial and axial inertia, are potential sources of
inaccuracy for flow stress data. The paper presents the main
design-guidelines followed when developing a high-performance SHPB
system for the determination of accurate flow curves. The results from
hot compression tests carried out on Aluminium- and Nickel-alloys prove
that with the developed system most of the limitations of ordinary-SHPBs
are overcome and system performances significantly improve.
|
|
Flow Stress, Yield Criterion and Constitutive Equation of Mushy/Semi-Solid Alloys
|
|
M. Kiuchi (1), J. Yanagimoto , H. Yokobayashi
|
|
STC F, 50/1/2001, P.157
|
|
Keywords: Semi -solid, Yield, Deformation |
Abstract : New mathematical models of yield criterion and constitutive
equations of mushy/semi -solid alloys (hereinafter described as semi
-solid alloys) are proposed in order to investigate their flow features
and deformation characteristics in various forming and shaping
processes. First, a large number of uniaxial compression tests of semi
-solid alloys are carried out and their stress -strain curves are
measured. Through the tests, the remarkable drop of their flow stress is
observed when their solid fraction decreases from 100%37;. The second, a
new formula of yield criterion of semi -solid alloys is proposed. It can
express the drop of their flow stress in semi -solid state. In addition,
so -called constitutive equations, which describe flow and deformation
of such alloys in forming and shaping processes, are derived from the
formulated yield criterion. At the last stage, the obtained constitutive
equations are introduced to 3D FEM simulation of upsetting of billets.
|
|
Ironing of thin walled cans
|
|
J. Danckert (1)
|
|
STC F, 50/1/2001, P.165
|
|
Keywords: Ironing, Die design, FEM |
Abstract : The ironing of thin walled cans has been analysed using the
slab method and FEM. The results show that there exists a critical
reduction ratio at which the ironing process may become unstable (or not
selfcentring). The results obtained show that the critical reduction
ratio is heavily influenced by the geometry of the ironing die (semi-die
angle and length of the die land), the friction conditions and the
strain hardening of the material. An increase in the semi-die angle
and/or length of the die land decreases the critical reduction ratio. If
the friction coefficient in the punch-can interface is increased
compared to the friction coefficient in the die-can interface, the
critical reduction ratio increases. The critical reduction ratio also
increases if the strain hardening of the can material is increased.
|
|
Investigation of Ecology Friendly Lubrication in High Speed Drawing Of SSID Tubes
|
|
R. Shivpuri (2), D. Bhaskararao, S. Mukherjee, S.D. Kini
|
|
STC F, 50/1/2001, P.169
|
|
Keywords: drawing, lubrication, ecology |
Abstract : Tubes used in the chemical and fluid power industry have
special inner surface roughness requirements. To meet these
requirements, it was decided to explore the mandrel drawing of carbon
steel tubes to submicron surface finish and thereby reduce the need for
machining and honing the inner diameter of the tube. An additional goal
was to investigate the use of ecology friendly solid lubricant in the
mandrel drawing process. First, a roughness model was developed which
relates the interface parameters such as effective stress to roughness
changes and lubrication parameters. This model was calibrated using
industrial experiments on a draw bench. Then a design of experiment was
carried out to relate the tube drawing phenomenological parameters such
as die angles, reduction and drawing speed to the interface parameters.
These two models were then integrated to predict the surface roughness
changes at the inner surface of the tube during mandrel drawing. It was
found that the new lubricant is able to provide good surface finish for
typical tube drawing reductions with and without the conversion coating.
However, for reductions larger than 40%37; it cannot prevent die pick up.
At drawing speeds greater than 0.5 m/s it is effective in preventing die
pick up but cannot deliver SSID surface finish in drawn tubes.
|
|
Prediction of service life and failure probability of cold forging tools
|
|
M. Geiger (1), B. Falk
|
|
STC F, 50/1/2001, P.173
|
|
Keywords: Simulation, Tooling, Fatigue |
Abstract : Tools systems for the production of cold forged parts,
especially for parts with net-shape or near-netshape attributes, can be
denoted as extremely high stressed technical components. Due to this
circumstance they often fail by fatigue crack initiation in surface
areas, which are characterised by high load levels. Therefore, the
primary goal of this publication is to present a methodology for the
lifetime calculation of cold forging tools. Beside the principle demand
? the improvement of the prediction accuracy ? a so-called
stochastic-deterministic method enables it to trace back the stochastic
lifetime characteristics to the scatter of the primary parameters of
influence and the fatigue properties of the tool material.
|
|
Development of a formulation to describe the work softening behaviour of magnesium sheets for heated deep drawing processes
|
|
E. Doege (1), G. Kurz
|
|
STC F, 50/1/2001, P.177
|
|
Keywords: Sheet metal, Forming, Processing |
Abstract : Experimental investigations at the Institute for Metal Forming
and Metal Forming Machine Tools (IFUM) demonstrate that magnesium sheets
possess excellent formability, if the process is conducted at higher
temperatures. The investigations are concentrated on improving the
forming behaviour of commercial magnesium alloys. For the understanding
of the forming behaviour of these materials a detailed evaluation using
tensile tests conducted at elevated temperature is required. Because the
flow stress decreases with increasing straining, which is represented by
the so-called work softening, no appropriate material formulation is
available. Furthermore, deep drawing tests with a locally different
temperature distribution in the die and blank holder show an additional
extension of the forming limits of magnesium sheet material. The
obtained results lead to the conclusion that for certain applications it
is possible to substitute conventional aluminium and steel sheets by
using magnesium sheet metal wrought alloys.
|
|
A simple experiment to characterize material formability in tube hydroforming
|
|
L. Filice, L. Fratini, F. Micari (2)
|
|
STC F, 50/1/2001, P.181
|
|
Keywords: Tube, Forming, FEM |
Abstract : In tube hydroforming processes an internal fluid pressure is
utilized to form the material on a properly shaped die; during the
process the material axial movement is favoured by the axial feeding of
an active punch. In the paper a simple experiment is presented aimed to
investigate the influence of the main process variables on material
formability. This equipment has enabled an extensive experimental
investigation; furthermore a numerical analysis based on the finite
element technique has been performed and a ductile fracture criterion
has been implemented to predict the insurgence of bursting defects.
|
|
Adaptive FEM Simulation for Tube Hydroforming: a Geometry-Based Approach for Wrinkle Detection
|
|
M. Strano, S. Jirathearanat, T. Altan (1)
|
|
STC F, 50/1/2001, P.185
|
|
Keywords: Tube HydroForming, FEM, Wrinkling |
Abstract : The success of Tube HydroForming (THF) operations is largely
dependent on the selection of the loading paths: internal pressure vs.
time and axial feed vs. time. The Finite Element Method is often used to
reduce the cost of prototyping. In this paper, the adaptive simulation
concept is presented as an effective FEM approach, able to select a
feasible THF loading path within a minimum number of simulation runs or
even within a single run. The adaptive simulation technique is based on
the ability to detect the onset and growth of defects (wrinkling,
buckling, bursting) and to promptly readjust the loading paths. The
detection and quantitative evaluation of wrinkles play a key role in the
implementation of the adaptive simulation. Therefore, a new geometrical
wrinkle indicator is introduced and evaluated with numerical and
experimental evidence. The proposed wrinkle indicator is computationally
inexpensive, suitable for many die shapes and sensitive to different
kinds of wrinkles.
|
|
Development of Micro Punching System
|
|
B.Y. Joo, S.I. Oh (1), B.H. Jeon
|
|
STC F, 50/1/2001, P.191
|
|
Keywords: micro hole, micro punching, alignment |
Abstract : A micro hole punching system was developed and micro holes of
100µm in diameter were successfully made on brass sheets of 100µm in
thickness. A micro punch made of tungsten carbide was designed to
withstand the punch load, considering the buckling and the bending
moment due to possible misalignment error. The punch was fabricated by
the grinding process with diamond wheel. The die was designed
considering the punch load and fabricated by micro electrodischarge
machining process. In this system the stripper is designed to guide
punch tip to minimize the possible misalignment. The punch was installed
on a vertical stepper and the die was mounted on an X-Y translation
unit. The precision motion controller controlled all motions of the
micro hole punching system. In this study technical difficulties and
solutions in the micro hole punching process were also discussed.
|
|
Analysis of flat rolling of superconducting silver/ceramic composites
|
|
J.I. Bech, M.S. Nielsen, M. Eriksen, F. Toussaint, p. Doremus, N. Bay (1)
|
|
STC F, 50/1/2001, P.201
|
|
Keywords: Superconductors, Rolling, Composites |
Abstract : The flat rolling process from wire to tape is presumably the
most crucial link in the chain of mechanical processes leading from
loose powder and silver tubes to the final superconducting Ag/BSCCO
tape. In order to improve the critical current density of the
superconducting filaments, one must process these to the highest
possible density without at the same time introducing failures as large
cracks and macroscopic shear bands. In order to analyse and optimise the
process, the interaction between the involved materials and their very
different mechanical properties must be taken into account. The silver
is considered an incompressible von Mises material, hardening as a
function of equivalent strain. The powder on the other hand is a
compressible friction material implying pressure dependent ?flow
stress?. In this paper particular attention is paid to stresses and
strains and defects in the deformation zone. The evolution of density in
the powder cores is analysed by the finite element method.
|
|
Identification of Parameters in the History Dependent Constitutive Model for Steels
|
|
M. Pietrzyk / J. Jedrzejewski (1)
|
|
STC F, 50/1/2001, P.161
|
|
Keywords: Metal forming, Flow stress model, Parameter |
Abstract : The problem of an influence of history of deformation on
material behaviour during hot forming of steels is discussed in the
paper. The method of description of the yield stress, which accounts for
a strain path, is pre-sented. This approach is based on an internal
variable method and it uses dislocation density for a descrip-tion of
the state of the material. Identification of the material parameters in
this model is the main difficulty, which prevents its practical
application. Therefore, an inverse analysis combined with the
experimental data is used in this work for an identification of these
unknown parameters. The experiment composed axisymmet-ric hot
compression performed at various temperatures and at various strain
rates on the Gleeble 3800 simu-lator. After identification the flow
stress model was implemented into the finite element program and
simula-tions of various hot forming processes were performed.
|
|
Influencing the Friction in Metal Forming Processes by Superimposing Ultrasonic Waves
|
|
K. Siegert (1), J. Ulmer
|
|
STC F, 50/1/2001, P.195
|
|
Keywords: ultrasonic, forming, friction |
Abstract : The possibility of influencing the friction in metal forming
processes by superimposing ultrasonic waves will be discussed in
general. It can be shown by experimental investigations that it is
possible to reduce the friction forces and to improve the surface
quality of formed parts. A new friction law including the influence of
superimposed ultrasonic waves and the surface and lubrication properties
will be described.
|
STC G |
|
Temperatures in High Efficiency Deep Grinding (HEDG)
|
|
W.B. Rowe (1), T. Jin
|
|
STC G, 50/1/2001, P.205
|
|
Keywords: Grinding, Modelling, Temperatures |
Abstract : A thermal model is presented for deep grinding with particular
relevance to the HEDG process. HEDG is defined as deep grinding at high
workspeeds and very high removal rates. The contact between the
workpiece and wheel is represented as a circular surface. It is found
that the contact angle and also the Peclet number (widely used in heat
transfer and defined below) have strong effects on the grinding zone
temperatures. Experiments were carried out to demonstrate the high
removal rates achievable and to measure the resulting contact
temperature. It was found that high removal rates and absence of thermal
damage could be achieved as predicted. The new model is shown to provide
a good estimation of contact temperatures. It is also confirmed that
HEDG can achieve low specific grinding energy compared with shallow
grinding and creep grinding. The chips take away a substantial
proportion of the heat generated in the grinding process. As in creep
grinding, burn-out of the coolant causes a steep rise in contact
temperature of the workpiece.
|
|
An Investigation of the Effect of Machine Loop Stiffness on Grinding of Ceramics
|
|
B. Zhang (2)
|
|
STC G, 50/1/2001, P.209
|
|
Keywords: machine loop stiffness, surface grinding, residual workpiece strength |
Abstract : This experimental study deals with the effect of machine
structural loop stiffness on grinding of ceramics. The objective of the
study is to investigate how the loop stiffness affects grinding forces,
wheel actual depth of cut (ADOC) and workpiece strength. A compliant
workholder is specifically designed and attached to a precision grinder
to simulate grinding machines of various compliances so that the effect
of machine loop stiffness can be isolated under otherwise identical
conditions. Silicon nitride is used as workpiece material and ground
with diamond wheels of two bond types and three grit sizes at machine
loop stiffness of four different levels. The ground workpieces are
assessed in terms of residual workpiece strength, grinding damage,
grinding forces, and ADOC. Theoretical analyses are given to indicate
that machine loop stiffness can affect on normal grinding forces and
workpiece strength. A discussion is provided to reveal how residual
workpiece strength is affected by residual stress and grinding-induced
damage.
|
|
Dynamic Behaviour of Cylindrical Traverse Grinding Processes
|
|
M. Weck (1), N. Hennes, A. Schulz
|
|
STC G, 50/1/2001, P.213
|
|
Keywords: Traverse grinding, Dynamic stability, Computer simulation |
Abstract : Compared to cylindrical plunge grinding processes the
conditions of contact in cylindrical traverse grinding processes are
much more complex, so that it is hardly possible to derive an analytical
stability criterion. Because of this, a numerical simulation tool has
been developed, to research the dynamic behaviour in the time domain and
to determine stable machining parameters of cylindrical traverse
grinding processes. The simulation tool is based on a process model,
including the dynamic compliance of the machine tool, the grinding
normal forces, the grinding wheel wear and the surface of workpiece and
grinding wheel. Special attention was paid to the conditions of contact,
regarding the development of step wear of the grinding tool.
|
|
Application of AE Contact Sensing in Reliable Grinding Monitoring
|
|
J.F.G. de Oliveira, D.A. Dornfeld (1)
|
|
STC G, 50/1/2001, P.217
|
|
Keywords: Grinding, Process monitoring, Acoustic emission |
Abstract : The low repeatability of the AE RMS level and its weak
correlation with some grinding quantities has been the main problem that
limits the use of this sensing technique in industrial environments.
This paper presents results on the influence of some measuring
conditions on the AE information. Some reliable grinding monitoring
functions are proposed for production based on fast RMS analysis and
binary contact detection techniques. An innovative grit mapping
technique is introduced based on these new concepts. Some examples of
application that include information about the topographic
characteristics of a grinding wheel and its transformation during
grinding are presented.
|
|
Ultraprecision Micro-Grinding of Germanium Immersion Grating Element for Mid-Infrared Super Dispersion Spectrograph
|
|
H. Ohmori, N. Ebizuka, S. Morita, Y. Yamagata / H. Kudo(1)
|
|
STC G, 50/1/2001, P.221
|
|
Keywords: ultra-precision grinding, grating element, electrical tool shaping |
Abstract : The design of a mid-infrared high dispersion spectrograph with
a resolution of 200,000 at 10mm employing germanium immersion grating
elements is required for the ?SUBARU? large space telescope. The authors
applied an ultraprecision micro-grinding technique using fine-diamond
grinding tools whose edges have been sharpened by electrical and
mechanical processes to fabricate the element, and successfully obtained
the required element with a sharp and smooth V-faced grating structure
using germanium. The successful fabrication of this element is expected
to contribute to the production of a compact and efficient high
dispersion spectrograph in the development of the most advanced image
analyzer.
|
|
Development of Single Step Grinding System for Large Scale ?300 Si Wafer: A Total Integrated Fixed-Abrasive Solution
|
|
H. Eda, L. Zhou, H. Nakano, R. Kondo, J. Shimizu / T. Nagao (1)
|
|
STC G, 50/1/2001, P.225
|
|
Keywords: Silicon wafer, Grinding, Positioning |
Abstract : This research has developed an integrated manufacturing system
for ?300mm silicon wafer, using fixed abrasive instead of conventional
free slurry, to provide a totally integrated solution for achieving the
surface roughness Ra < 1nm (Ry < 5~6nm) and the global flatness <
0.2µm/?300mm. In addition to the space saving, this integrated system
also significantly reduces the total energy consumption by 70%37;, compared
with the current process used for ?200mm Si wafer. Three core
technologies: the hybrid process mechanics, the GMM (giant
magnetostrictive material) actuated positioning/alignment device and the
ecologically friendly coolant circulation system are described in this
paper. The system performance and results are then presented and discussed.
|
|
Process Analysis for the Evaluation of the Surface Formation and Removal Rate in Lapping
|
|
U. Heisel (1), J. Avroutine
|
|
STC G, 50/1/2001, P.229
|
|
Keywords: Lapping process, Grain motion analysis, Surface topography |
Abstract : During the process of lapping, the mechanisms of surface
formation and removal rate are decisively influenced by the movement
type of the individual grains within the lapping abrasive. Two active
movement types can be differentiated. These are the rolling and sliding
of the individual lapping grains within the working gap in relation to
one of the working partners as well as the passiveness of the grains,
whereby varying surface topographies of the workpiece are created by
active movement types. These can among others be influenced by some of
the adjustable process parameters. However, the most important parameter
is the significant grain form. On this basis, a simulation model for the
analysis of the surface formation by the motion of grains is described
in this paper, also considering collisions and break-ups of grains. It
enables the quantitative specification of the individual movement types
of the lapping grains under the influence of different process
parameters. These are for example the lapping pressure, lapping speed,
grain size, grain concentration etc as well as the qualitative
estimation of these influences on the processing result.
|
|
Mechanisms of the Chemical Mechanical Polishing (CMP) Process in Integrated Circuit Fabrication
|
|
N. Saka, J.-Y. Lai, J.-H. Chun (2), N.P. Suh (1)
|
|
STC G, 50/1/2001, P.233
|
|
Keywords: Chemical Mechanical Polishing, Semiconductor Manufacturing, Integrated Circuits |
Abstract : A contact mechanics model that describes the polishing
mechanisms of copper-patterned silicon wafers in the fabrication of
ultra-large-scale integrated (ULSI) circuits is presented. The model
explains the die-scale variation of material removal rates due to
pattern geometry, and predicts results that are in agreement with
experimental observations. When the width of the copper interconnect is
less than 0.5 µm, dishing of interconnects is less than 20 nm and thus
does not contribute much to surface nonuniformity. However, because the
overpolishing rate varies with the copper area fraction, it may
contribute to die-scale nonuniformity.
|
|
Fracture Strength of Zero-Thermal-Expansion Glass-Ceramics for Ultra-Precision Components
|
|
Y. Namba, H. Takehara, Y. Nagano / T. Masuzawa (1)
|
|
STC G, 50/1/2001, P.239
|
|
Keywords: Glass-ceramic, Fracture strength, Ultra-precision machining |
Abstract : Zero-thermal-expansion glass-ceramic is a key material in
ultra-precision engineering. However, applications of this material have
been limited in static components, because of a lack of data on the
fracture strength of this material. We examine the fracture strength of
the material by means of a 4- point bending test on samples machined
using various methods. Etching technology is useful in increasing the
strength, which strongly depends upon the surface roughness after
etching. The floatpolished sample has a fracture strength of 546MPa,
which is more than 4 times higher than that of normally machined
surfaces, and also much higher than that of alumina.
|
STC M |
|
High Speed Nanometer Positioning Using a Hybrid Linear Motor
|
|
H. Shinno (2), H. Hashizume
|
|
STC M, 50/1/2001, P.243
|
|
Keywords: Nano-technology, Ultra-precision machine, Nano-positioning |
Abstract : With ever increasing demand for higher accuracy and
productivity, high speed ultraprecision table positioning technology is
urgently required. In order to achieve nanometer positioning accuracy
and high speed feed drive of the table, it is effective to minimize
error factors in the table system by using a linear motor in perfect
noncontact condition. In such a linear motor-driven table system of a
noncontact type, however, the force ripple of the motor directly
influences the linear motion error of the table. In this study, a hybrid
linear motor has been developed which has no force ripple. The proposed
hybrid linear motor is constructed from a voice coil motor and a coarse
driving mechanism, e.g., a wire drive. Furthermore, a hybrid linear
motor-driven aerostatic table system has been developed and the
performance of the table system has been evaluated.
|
|
A Study on Development of an Open Servo System for Intelligent Control of a CNC Machine Tool
|
|
M. Mori, K. Yamazaki (1), M. Fujishima1, J. Liu, N. Furukawa
|
|
STC M, 50/1/2001, P.247
|
|
Keywords: Open-Servomechanism, Intelligent Control, CNC Machine Tool |
Abstract : An open servo control system for an intelligent CNC machine
tool system has been proposed and developed. The developed system is
equipped with real-time access window, through which user custom
application software can monitor or modify any parameters and variables
of servo system in a real time manner as a parallel session while the
standard servo control is being performed. The developed system has been
implemented in a CNC vertical machining center for feasibility study by
integrating the software model reference adaptive control as custom
application. The experimental results have successfully demonstrated the
effectiveness of the open servo system.
|
|
A Process Oriented Approach to Automated Quality Control
|
|
C. Ament, G. Goch (2)
|
|
STC M, 50/1/2001, P.251
|
|
Keywords: Quality Assurance, Distributed Control, Holonic Manufacturing System |
Abstract : To guarantee a constant quality of manufactured products, it
is necessary to optimise the process parameters immediately when
deviations of the workpiece quality have been observed. Established
methods of quality management are only able to register quality
deviations (like the statistical process control) or to analyse them
offline with the help of experts (like failure mode and effects
analysis). The presented approach develops a process oriented automated
quality control for manufacturing in two steps: First, a local quality
controller stabilises the product quality to reference values in the
pace of workpiece production. In order to obtain the control law for the
process parameters, a learning approach is applied. In the second step,
the information exchange between the local controllers is established
parallel to the workpiece flow in order to obtain an optimised global
process. As an example, the method is applied to quality control in the
turning process.
|
|
Attenuation of Vibrations due to Unbalance of an Active Magnetic Bearings Milling Electro-Spindle
|
|
V. Tamisier, S. Font, M. Lacour, F. Carrère, D. Dumur (1)
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|
STC M, 50/1/2001, P.255
|
|
Keywords: computer numerical control, vibration, milling electro-spindle |
Abstract : Among the advantages of active magnetic bearings, the absence
of contact, the lifetime and the safety can be put forward. This paper
presents first a new technology of milling electro-spindle equipped with
a permanent magnet motor and active magnetic bearings. Then due to the
use of numerical controllers, the implementation of advanced algorithms
is easily performed, to ensure a numerical compensation of the rotor
unbalance. The aim is to determine the value of the rotor unbalance when
classical adaptive compensation methods can?t be used for stability
reasons. Finally, by reducing the synchronous vibration due to the rotor
eccentricity without destabilizing the system, a better resulting
surface of the workpiece is expected while avoiding amplifiers saturation.
|
|
A Cutting Performance Based Template for Spindle Dynamics
|
|
S. Smith (2), J. Snyder
|
|
STC M, 50/1/2001, P.259
|
|
Keywords: Cutting performance, dynamic, milling |
Abstract : The stable metal removal rate in milling depends on the
dynamic characteristics of the tool-holderspindle system. We present a
methodology for determining the permissible dynamic characteristics
based on the intended cutting operation. We produce a template that
bounds the tool-tip frequency response function (FRF). Measured FRFs can
be compared against the template to check cutting performance. The
template can be used in design to match the spindle system to the
intended application. The template accounts for lobing effects, multiple
modes, process damping, and static stiffness. It accounts for damping
variability, producing a safe-side estimate. Experimental results
illustrate the template?s use.
|
|
Improving High-Speed Machining Material Removal Rates by Rapid Dynamic Analysis
|
|
T. L. Schmitz, M. A. Davies (2), K. Medicus, J. Snyder
|
|
STC M, 50/1/2001, P.263
|
|
Keywords: High speed machining, Material removal rate, Sub-structure analysis |
Abstract : Stability prediction and chatter avoidance in high-speed
machining requires knowledge of the tool point dynamics. In this paper,
three advances toward the rapid identification of the tool point
frequency response and corresponding stable cutting parameters are
described: 1) stable speeds determination using non-contact periodic
impulsive excitation of the tool point (produced by spindle rotation and
a stationary magnet) in conjunction with once-per-revolution sampling,
2) Receptance Coupling Substructure Analysis for the analytic prediction
of the tool point response, and 3) once-per-revolution sampling of the
audio signal during cutting to determine stability behavior.
|
|
Reconfigurable Machine Tools
|
|
R.G. Landers, B.-K. Min, Y. Koren (1)
|
|
STC M, 50/1/2001, P.269
|
|
Keywords: Machine Tool, Machine Tool Module, Conversion |
Abstract : The uniqueness of Reconfigurable Manufacturing Systems (RMSs)
is that the structure of the system as well as of its machines and
controls can be rapidly changed in response to market changes (demand
and products). A major component of RMSs is the reconfigurable machine
tool (RMT). By contrast to conventional CNCs that are general?purpose
machines, RMTs are designed for a specific, customized range of
operation requirements and may be cost?effectively converted when the
requirements change. In this paper, systematic design tools that have
been recently developed for RMTs are reviewed, and three examples are
provided to compare RMTs to traditional types of machine tools.
|
|
Development of an Intelligent High-Speed Machining Center
|
|
M. Mitsuishi(2), S. Warisawa, R. Hanayama
|
|
STC M, 50/1/2001, P.275
|
|
Keywords: Remote Manufacturing System, In-Process Monitoring, Thermal Deformation |
Abstract : This paper describes a method for constructing an intelligent,
high-speed machining system. According to the stability lobe diagram
theory, there may exist a wide, stable cutting area at high spindle
speeds. When cutting in this regime, it is possible to realize high
productivity and efficiency and produce high quality products. On the
other hand, when the spindle speed is high, the power consumption of the
spindle motor is high and the prevention and control of thermal
deformation is crucial. Furthermore, a machining state monitoring method
in high spindle speed area should be established. The developed system
has the following features: (1) active thermal deformation compensation
function, (2) a real-time machining state judging function, and (3) a
remote operation function using a computer network.
|
|
Performances of HSK Tool Interfaces under High Rotational Speed
|
|
T. Aoyama, I. Inasaki (1)
|
|
STC M, 50/1/2001, P.281
|
|
Keywords: Tooling, Machining, Finite element Method (FEM) |
Abstract : The static and dynamic performance of the HSK tool interface
is investigated at high rotational speed, including an experimental and
numerical analysis of the influence of spindle speed on the radial
stiffness of the tool interface. The behavior of the flange and taper
contact of the HSK tool interface is simulated by means of the finite
element method. The performance of a 7/24 tapered tool interface is also
evaluated using the same spindle system, and the advantages of using HSK
tool interfaces in machining are discussed.
|
|
Analysis and Improvement of Motion Accuracy of Hydrostatic Feed Table
|
|
E. Shamoto, C.-H. Park, T. Moriwaki (1)
|
|
STC M, 50/1/2001, P.285
|
|
Keywords: Motion accuracy, Hydrostatic feed table, Transfer function |
Abstract : A new model is developed to analyze motion accuracy of
hydrostatic feed tables and an algorithm is proposed to improve their
accuracy. Relationship between film reaction force in a single
hydrostatic pad and profile errors of a guide rail is derived at various
spatial frequencies by FEM analysis, and it is expressed as a transfer
function. This transfer function clarifies so called averaging effects
of oil film quantitatively. Furthermore, the transfer function is
utilized to estimate error motion of a multiple pad table from measured
profiles of its guide rail, and to reversely estimate the profiles from
measured error motion. A new method is proposed to improve the motion
accuracy by lapping the rail surfaces so as to eliminate the estimated
profile error. Its validity is verified analytically and experimentally
in the present research, and a straight motion accuracy of 0.07 µm and
1.42 arcsec was achieved over a stroke of 250 mm after the corrective
lapping.
|
|
Process Simulation and Paint Thickness Measurement for Robotic Spray Painting
|
|
M.A.S. Arikan (2) , T. Balkan
|
|
STC M, 50/1/2001, P.291
|
|
Keywords: Robotic spray coating, Coating measurement, Automated measurement |
Abstract : A method and a computer program are developed for modeling of
spray painting process, simulation of robotic spray painting, off-line
programming of industrial robots and paint thickness measurement for
painting of curved surfaces. The computer program enables the user to
determine the painting strategies, parameters and paths. Surface models
of the parts that are to be painted are obtained by using a CAD
software. For paint thickness measurements, probe of the coating
thickness measurement gage is attached to the wrist of the robot by
using a feedback/safety adapter designed and manufactured for this
purpose. Thicknesses are measured and transferred to the computer
automatically. Then, obtained thickness data is processed and
comparisons between simulated and measured thicknesses are made.
|
|
Design and Test of a Safe Numerical Control for Robotic Surgery
|
|
T. Bürger, U. Laible, G. Pritschow (1)
|
|
STC M, 50/1/2001, P.295
|
|
Keywords: NC, Safety, Hexapod |
Abstract : Automated systems in safety critical applications require
particularly safe control systems. This paper presents the design and
test of a fail-safe numerical control (NC) for robotic surgery, which is
currently assisting in a wide range of surgical treatments. The
mechanical part of the robot system is based on a hybrid kinematics
consisting of a hexapod and a linear axis in series. Since medical
devices require a CE certification by a notified body, this paper also
describes the required regulations, which build the basis for the safety
concept. This multilevel safety concept is also transferable to standard
NCs of machine tools.
|
STC O |
|
Systematic Design of Manufacturing Systems Based on Axiomatic Design Approach
|
|
P. Gu (2), H.A. Rao, M.M. Tseng (1)
|
|
STC O, 50/1/2001, P.299
|
|
Keywords: Manufacturing System, Design Axioms, Design Methodology |
Abstract : Rapid changes in product demand, product design and
introduction of new products and increasing global competition require
manufacturing systems to be highly flexible, adaptable and responsive.
These characteristics of a manufacturing system must be addressed at the
design stage. This paper presents a method for design of manufacturing
systems by combining the axiomatic design approach and systematic design
approach. The methodology explains how design axioms are used during
different design stages, and also provides a step-bystep approach for
the design of manufacturing systems. A case study of a furniture
manufacturing system design is prov ided to illustrate an application of
the method in real world manufacturing system design.
|
|
Disassembly Operation Support System with Motion Monitoring of a Human Operator
|
|
S. Takata (1), H. Isobe, H. Fujii
|
|
STC O, 50/1/2001, P.305
|
|
Keywords: Disassembly, support system, motion recognition |
Abstract : Improving efficiency of disassembling operations is one of the
key issues to facilitate part reuse and material recycling. In this
paper, we propose an operation support system that provides information,
such as disassembly sequence, necessary tools, and disassembly
directions, using 3D product models. To provide necessary information at
the proper instant, the system has a function of monitoring operator?s
motion by means of 3D position sensors attached on the backs of both
hands. The signals from the sensors are processed to extract features of
disassembly operations. Based on the recognition of the operations, the
system provides information for the operator via a head mount display.
The effectiveness of the system has been verified by applying a
prototype system to disassembly operations of copying machines.
|
|
Workflow management based on Information Management
|
|
D. Lutters, R.J. Mentink, F.J.A.M. van Houten (1), H.J.J. Kals (1)
|
|
STC O, 50/1/2001, P.309
|
|
Keywords: Information management, Integration, Workflow management |
Abstract : In manufacturing processes, the role of the underlying
information is of the utmost importance. Based on three different types
of integration (function, information and control), as well as the
theory of information management and the accompanying information
structures, the entire product creation process can be formulated in
terms of the information requirements of distinct processes. So-called
task chains can establish the correlation between processes. Using
formal representations of the information content (ontologies), a
flexible resolution of processsteps is achieved. Based on this, an
improved method for workflow management comes within reach.
|
|
An Autopoietic Approach for Building Knowledge Management Systems in Manufacturing Enterprises
|
|
M. Thannhuber, M.M. Tseng (1), H.-J. Bullinger
|
|
STC O, 50/1/2001, P.313
|
|
Keywords: Manufacturing system, Knowledge management, Intelligent processing |
Abstract : This paper discusses a new understanding of knowledge at the
enterprise level, which proposes to regard knowledge as a natural
concept to cope with dynamic changes of market demand, process design,
capabilities in diverse locations, and associated fluctuations in
internal process adaptations. Knowledge is considered as a natural
concept driving system behavior. Instead of focusing on individual human
knowledge, we identify the ability of an enterprise to dynamically
derive processes to meet the external needs and internal stability as
the organizational knowledge. Based on this approach, a new knowledge
management system has been developed. It consists of two key components:
The ?Declarative Processing Environment?, which allows processes to be
assembled goal-driven from a pool of process building blocks and the
?Autopoietic Framework? that mimics natural organisms to adapt to
environmental changes, new capabilities and new technology. The
framework continuously improves the pool of available process building
blocks and their selection. Manufacturing applications such as process
planning and supply chain management have been particularly suitable for
applying this new approach.
|
|
Line-less Production System Using Self-Organization: A Case Study for BMS
|
|
K. Ueda (1), I. Hatono, N. Fujii, J. Vaario
|
|
STC O, 50/1/2001, P.319
|
|
Keywords: Manufacturing, Production Systems, Adaptive Systems |
Abstract : The paper proposes a novel approach to the design of line-less
production systems. The approach is based on the concept of biological
manufacturing systems (BMS) that can deal with complexity in
manufacturing using the ideas of self-organization, evolution and
learning. In the line-less production systems, all production elements
can move freely on the production floor using self-organization in order
to adapt to fluctuations such as the diversity of production demands and
the malfunction of machines. The effectiveness of the line-less
production system is discussed and its feasibility is demonstrated by
computer simulation. Furthermore, a mini-factory consisting of small
autonomous robots is developed as a prototype of the line-less
production systems.
|
|
Self-organization in a distributed manufacturing system based on constraint logic programming
|
|
A. Sluga, p. Butala / J. Peklenik (1)
|
|
STC O, 50/1/2001, P.323
|
|
Keywords: Optimization, Multi-agent structure, Work system |
Abstract : The paper addresses the problem of self-organization of
manufacturing systems. The objective is to overcome the rigidity of
conventional hierarchical structures and to introduce structures that
are able to adapt to a dynamic environment. The presented approach is
based on the concept of Complex Adaptive Manufacturing Systems. It is
characterized by a decomposition of manufacturing objectives and
allocation of tasks to work systems as autonomous building blocks in a
dynamic environment. The allocation is based on a market mechanism that
enables self-organization and optimization of a manufacturing system by
evaluation and selection among competing work systems. The approach is
implemented in the Constraint Logic Programming environment Eclipse and
validated in a simulation experiment.
|
|
Process planning with conditional and conflicting advice
|
|
A. Markus (2), J. Vancza
|
|
STC O, 50/1/2001, P.327
|
|
Keywords: process planning, sequencing, constraints, optimization |
Abstract : Due to the vast amount and intricacies of technological
knowledge, the process planning problem, even for relatively simple
workpieces, can hardly be solved by a straightforward algorithm. The
paper shows that this problem is more readily tractable as satisfying
constraints that represent pieces of advice taken from experts. We de ne
a generic constraint-based model for process planning that handles
precedences and setup formation, as well as the mutual e ects of
operation sequencing and resource assignment. We demonstrate the use of
our model with examples of machining prismatic workpieces and bending
sheet metal parts.
|
|
Backlog-oriented Automatic Production Control
|
|
H.-P. Wiendahl (1), J.-W. Breithaupt
|
|
STC O, 50/1/2001, P.331
|
|
Keywords: Automatic, Production, Control |
Abstract : Conventional production control methods are normally based on
static models. Therefore, they are insufficient for mastering the
increasing dynamics in the companies? environment. In order to solve the
problem, this paper aims to present a new general concept for dynamic
modelling of job shop productions using methods of control theory. This
concept for the medium-term planning level is based on a feedback
control with defined reference and control variables. The developed
distributed backlog controller eliminates an arising backlog as fast as
possible by means of flexible capacities. Simultaneously, a central
WIPcontroller guarantees a defined WIP level within the shop by
controlling the total input rate into the job shop. Finally, the
logistical rationalisation potentials of Automatic Production Control
are pointed out by means of an industrial case study.
|
|
User-friendly Production Control Systems to Support the Flexibility of Production Organization
|
|
M. Meier, M. Baecker / W. Massberg (1)
|
|
STC O, 50/1/2001, P.335
|
|
Keywords: Production control, Information System Modelling, Computerized Simulation |
Abstract : Due to increasing global competition, growing pressure of time
and prices as well as the individualization of products, enterprises are
obliged to implement structural and process organizations which are
flexible and to optimise them permanently. As a result, flexible
information systems which on the one hand support new forms of
organization and on the other hand can be adapted efficiently by trained
personnel are required. The purpose of this paper is to present a
concept for a user-friendly production control system that is based on a
model based toolbox.
|
|
A Spatial Scheduling System for Block Painting Process in Shipbuilding
|
|
K.K. Cho (1), K.H. Chung, C. Park, J.C. Park, H.S. Kim
|
|
STC O, 50/1/2001, P.339
|
|
Keywords: Scheduling, Spatial Scheduling, Algorithm |
Abstract : This paper deals with a spatial scheduling problem for the
painting process in shipbuilding. This problem is complicated because
both scheduling and spatial allocation of the blocks in the paint shop,
and the workload balance among working teams should be considered
simultaneously. The spatial scheduling system for the block painting
process includes an operation strategy algorithm, a block scheduling
algorithm, a block arrangement algorithm, and a block assignment
algorithm. This system generates the block painting schedules that
satisfy due date, working space constraint, and workload balance among
working teams. This system has been tested using actual scheduling data
from a shipyard and successfully implemented in a paint shop in a
shipbuilding company.
|
|
Parallel Disassembly Sequencing with Sequence-Dependent Operation Times
|
|
J.-G. Kang, D.-H. Lee, p. Xirouchakis, J.-G. Persson (1)
|
|
STC O, 50/1/2001, P.343
|
|
Keywords: Disassembly, Sequencing, Environment |
Abstract : This paper focuses on the disassembly sequencing, which is the
problem of determining the disassembly level and the corresponding
disassembly sequence for a product at its end-of-life with the objective
of maximizing the overall profit. Parallel disassembly and
sequence-dependent operation times are considered by developing an
extended process graph obtained from a transformation of a conventional
AND/OR graph. Then, an integer programming formulation is developed with
precedence constraints that allows its resolution with standard
techniques. Finally, an optimal solution is obtained, with a reasonable
amount of computation time, for an industrial application of a
subassembly of a copy machine.
|
|
Continuous Improvement and Participative Factory Planning by Computer Systems
|
|
E. Westkämper (1), R. von Briel
|
|
STC O, 50/1/2001, P.347
|
|
Keywords: Digital Factory, Simulation, Virtual Reality |
Abstract : Turbulent influencing factors ? based on market requirements
and technological demands ? lead to a permanent change and improvement
in the factory processes, manufacturing systems and layouts. New
investigations in manufacturing show that the application of new
machining processes and tools require a systematic and stepwise change
of the layout and the organisation in order to activate the economic
potentials. It is evident that continuous improvement and optimisation
with the perspective to mediumterm objectives can be realised by means
of new methods and new computerised systems for factory planning.
Digital models and the technology of virtual reality allow the
continuous planning of changes in factories. This paper includes results
of the planning of future manufacturing systems and the systematics of
continuous planning based on digital modelling and virtual manufacturing.
|
|
Hybrid, AI- and simulation-supported optimisation of process chains and production plants
|
|
L. Monostori (1), Zs.J. Viharos
|
|
STC O, 50/1/2001, P.353
|
|
Keywords: Manufacturing Systems, Artificial Intelligence, Optimisation |
Abstract : The paper describes a novel approach for generating
multipurpose models of machining operations, combining machine learning
and search techniques. A block-oriented framework for modelling and
optimisation of process chains is introduced and its applicability is
shown by the results of the optimisation of cutting processes. The paper
illustrates how the framework can support the simulation-based
optimisation of whole production plants. The benefits of substituting
the time-consuming simulation by ANN models are also outlined. The
applicability of the proposed solution is demonstrated by the results of
an industrial project where the task was to optimise the size spectrum
of the ordered raw material at a plant producing one- and multi-layered
printed wires.
|
STC P |
|
Opto-tactile Sensor for 2D and 3D Measurement of Small Structures on Coordinate Measuring Machines
|
|
H. Schwenke, F. Wäldele, C. Weiskirch, H. Kunzmann (1)
|
|
STC P, 50/1/2001, P.361
|
|
Keywords: Coordinate measuring machine (CMM), Probe, Micro-parts |
Abstract : A novel tactile probing system for dimensional measurement of
small structures is presented. The measurement principle combines
optical and mechanical techniques and allows probing elements below 50
µm to be realized. The measurement uncertainties achievable are in the
sub-micron order. With this full 3D sensitivity on the basis of the
opto-tactile concept is achieved. Some exemplary measurements show the
capability of the new sensor.
|
|
Development of a Silicon-based Nanoprobe System for 3-D Measurements
|
|
H. Haitjema, W.O. Pril, P.H.J. Schellekens (1)
|
|
STC P, 50/1/2001, P.365
|
|
Keywords: CMM-probe, silicon, MEMS |
Abstract : A small 3-D probe system was developed based on sensing the
bending of elastic hinges carrying the probe stylus. The stylus platform
and elastic hinges are etched in silicon. On the elastic hinges,
piezoresistive straingages are integrated, including the necessary
wiring. The 3-D measurement range is about one hundred micrometres in
each direction and the repeatability is at the nanometre level. Several
prototypes of these MEMS-type probe were realised in IC-technology
successfully. Calibrations with a displacement generator based on laser
interferometry reveal typical repeatabilities in the nanometre level and
a 3-D uncertainty of the order of 25 nm.
|
|
A System for Measuring High-reflective Sculptured Surfaces Using Optical Noncontact Probe
|
|
G.X. Zhang (1), Y.C. Xu, Z.X. Xie, Y. Du, Z. Li
|
|
STC P, 50/1/2001, P.369
|
|
Keywords: Measurement, Sculptured Surface, Probe |
Abstract : With the development of industry more and more high-reflective
sculptured surfaces are required to be measured quickly and accurately.
For solving this problem a new optical probe with three incidence lights
and a receptor has been developed. Two polarizing plates with mutually
perpendicular polarizations are used to eliminate the disturbance of the
specular light. A system based on 3-D coordinate measuring machine,
PH10M motorized head and the new developed probe has been built. The
system can track and measure the unknown free form sculptured surface
automatically. Measures for improving accuracy and performance of the
system are studied. The effectiveness of the proposed system has been
tested by experiments.
|
|
Dynamics and Control of the UNCC/MIT Sub-Atomic Measuring Machine
|
|
R.J. Hocken (1), D.L. Trumper (2), C. Wang
|
|
STC P, 50/1/2001, P.373
|
|
Keywords: Ultra-precision, Control, Servomechanism |
Abstract : This paper reports on the design, modeling, implementation,
and experimental results for the control of our Sub- Atomic Measuring
Machine (SAMM), which has been jointly developed by UNC-Charlotte and
MIT. This machine is intended for measuring features on planar
substrates with a work volume of 25 mm ´ 25 mm ´ 100 mm, with subatomic
resolution. The machine uses four linear motors to control motion in six
degrees of freedom and provide magnetic suspension. We derive the
commutation law for these linear motors based on a least self-heating
condition. We also present modeling of the stage motion in six
degrees-of-freedom and our controller design using state-space methods.
The experimentally-demonstrated RMS stage positioning noise is 0.12 nm
in x, 0.082 nm in y, 1.45 nm in z, 22 nrad in qx, 18 nrad in qy, and 2.7
nrad in qz over a 25 second measurement.
|
|
Compensation of Static and Transient Thermal Errors on CMMs
|
|
J.-P. Kruth (1), P. Vanherck (1), C. Van den Bergh
|
|
STC P, 50/1/2001, P.377
|
|
Keywords: Metrology, Thermal deformation compensation, Coordinate measuring machine |
Abstract : Using CMMs under normal workshop conditions necessitates to
take into account the influence of environmental temperature on the
machine structure. Non-standardised environmental conditions result in
temperature dependent measurement errors. The paper presents a
parametric approach to describe the relation between transient
temperature distributions and resulting deformation of the CMM. The
focus lies on broadening the temperature range in which the original
accuracy specifications can be guaranteed. Starting from a correction
scheme for uniform, invariant temperature situations, an approach for
transient environmental loads is developed. Based on a limited number of
temperature inputs, the required correction coefficients for the probe
position are calculated.
|
|
Advances in Precision Machining of Steel
|
|
E. Brinksmeier (1), R. Gläbe
|
|
STC P, 50/1/2001, P.385
|
|
Keywords: Ultra-precision machining, Steel, Tool wear |
Abstract : Precision machining of steel with geometrically defined
diamond cutting tools is handicapped by excessive tool wear. We have
revisited solutions proposed in the literature and investigated some new
approaches. Care has been taken to identify the mechanisms responsible
for chemical and abrasive wear and to quantify tool wear in well defined
cutting experiments.
|
|
Grazing Incidence Interferometry for High Precision Measurements of Cylindrical Form Deviations
|
|
A. Weckenmann (2), J. Bruning, S. Patterson, p. Knight / J. Bryan (1)
|
|
STC P, 50/1/2001, P.381
|
|
Keywords: Laser, Optical, Metrology |
Abstract : Grazing incidence interferometers equipped with diffracting
elements (computer generated holograms) are now being used to measure
the cylindricity, roundness and straightness of cylindrical parts. The
method is non-contact, with automatic work piece alignment and is
capable of recording thousand of points on the surface in a few seconds.
It incorporates parallel data acquisition of the cylindrical surfaces,
so that an excellent radial resolution can be obtained. There are some
questions regarding the basic theory and the accuracy when measuring
workpieces with short wavelength errors. Experimental results using a
CylinderMaster CM 25, and a modification for measuring blind holes are
presented.
|
|
New Design of Precision CMM based upon Volumetric Phase-Measuring Interferometry
|
|
S.-W. Kim / D.Y. Yang (1)
|
|
STC P, 50/1/2001, P.357
|
|
Keywords: CMM, Optical metrology, Machine design |
Abstract : A new design of high precision CMM is proposed by introducing
a volumetric interferometer system that is capable of measuring the
complete spatial motion of the probe in six degrees of freedom. This
design is intended to allow the CMM measurement to be free from the Abbe
offsets and angular motion errors of slide ways. The volumetric
interferometer operates on the principle of phase-measuring
interferometry and determines the 3-D coordinates of the probe by
monitoring the interference intensity of the two spherical wavefronts
emanated from two optical fibers of single mode propagation.
|
STC S |
|
High Sensitivity Optical Detection of Oriented Microdefects on Silicon Wafer Surfaces Using Annular Illumination
|
|
T. Miyoshi, S. Takahashi, Y.Takaya, S. Shimada(2)
|
|
STC S, 50/1/2001, P.389
|
|
Keywords: Optical measurement, Surface defect, Ultra-precision |
Abstract : A new optical measurement method detecting the microdefects on
silicon wafer surfaces, which can be applied to in-process measurement,
is presented in this paper. In our proposed method, a unique annular
incident light spot is imaged by an original dark field optical system
with a high-power objective lens. This annular incident light spot
enables the sensitive detection of the oriented microdefects such as
microscratches on the silicon wafer surface independent of its
direction. In order to verify the feasibility of our proposed method,
the basic and scanning experiments were performed for microgroove with
sub-micrometer scale. This results showed that the proposed measurement
method is effective for detecting the oriented microdefects.
|
|
Effect of Surface Oxidation on Micromachinability of Monocrystalline Silicon
|
|
T. Inamura (2), G.Y. Feng, N. Takezawa, N. Mohri
|
|
STC S, 50/1/2001, P.393
|
|
Keywords: Cutting, Micro machinability, Oxidation |
Abstract : Microcutting experiments are carried out under an atomic force
microscope (AFM) using workpieces of silicon monocrystals that have been
exposed to air for various lengths of time before cutting. The results
are observed under the same AFM with decreased tip force. The results
show that difficult-to-cut areas appear locally after 24 hours of
exposure time and these areas extend with increasing exposure time until
the whole surface is covered after 120 hours. It is also found that
exposure of workpieces to air produces a SiO2 surface layer in which
residual compressive stress is generated and whose hardness and/or
elastic constant are lower than those of bulk Si. The molecular dynamics
simulations carried out based on the above results show that the
deterioration of machinability of monocrystalline silicon is caused by
the viscoelastic/plastic properties of SiO2.
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Effects of Polishing on the Photoluminescence of Single Crystal ZnO
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D.A. Lucca (1), D.W. Hamby, M.J. Klopfstein, G. Cantwell, C.J. Wetteland, J.R. Tesmer, M. Nastasi
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STC S, 50/1/2001, P.397
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Keywords: Surface, Polishing, Sub-surface damage |
Abstract : The photoluminescence (PL) response of single crystal ZnO
subjected to mechanical and chemomechanical polishing has been
investigated. Zn-terminated and O-terminated surfaces of (0001)-
oriented ZnO crystals were prepared by mechanical polishing with 1/4 µm
and 1 µm diamond abrasives and by chemomechanical polishing. The
spectrally resolved room temperature PL of the polished surfaces was
measured, and changes in both the spectral content and PL intensity
introduced by polishing were assessed. The PL results were compared to a
direct measure of subsurface damage obtained by ion channeling. Room
temperature PL spectroscopy is shown to exhibit potential as a sensitive
tool for the characterization of subsurface damage in polished ZnO.
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Method for the Analysis of Residual Stress Induced Failure in Thin Films
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E. Uhlmann (2), K. Klein
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STC S, 50/1/2001, P.401
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Keywords: Coating, Residual Stress, Finite Element Method (FEM) |
Abstract : PVD thin film systems are generally exposed to high intrinsic
compressive stresses. These stresses are in fact desired as they are
accompanied by an increase in strenght. However, they lead to a coating
failure under higher loads. Therefore a method for the analysis of
residual stress induced failure mechanisms in thin films has been
developed. For this purpose defined turning profiles with varying
roughness values were created on HSS cylinders and subsequently coated.
Coating defects are the result of static loads caused by residual
stresses and when a critical maximum height is exceeded in the prepared
profile. Such defects can be verified by means of microscopy. By
calculating the stress gradients in the test structures with a FEM
model, the influences of the critical parameters can be discussed. The
results permit the optimisation of coating processes.
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