CIRP ANNALS 2004
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STC A |
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Design for Environment ? Do We Get the Focus Right?
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M.Z. Hauschild, J. Jeswiet (1), L. Alting (1)
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STC A, 53/1/2004, P.1
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Keywords: Sustainable product, Design, Product life cycle |
Abstract : Sometimes, products resulting from design for environment
(DFE) endeavours are sub-optimisations from an environmental
perspective, because the tool determines the process and not vice versa.
For a more systematic way of getting the focus right, a hierarchy of
focusing is introduced: 1. What is the function provided and what is the
optimal way of providing it while making a business out of it? Which
product should the company then produce? 2. Where are the ?environmental
hot spots? in the life cycle of this product? 3. Which DFE tool supports
optimisation of the product by reducing these hot spots?
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Web-Based System for Reverse Manufacturing and Product Environmental Impact Assessment Considering End-of-Life Dispositions
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H.C. Zhang (2), J. Li , P. Shrivastava, A. Whitley / M.E. Merchant (1)
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STC A, 53/1/2004, P.5
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Keywords: Life cycle, Reverse Manufacturing, Decision-making |
Abstract : Widespread usage of electronic equipment and
shortened product life cycles have challenged original equipment
manufacturers (OEMs) to handle End-Of-Life (EOL) product through
environmentally benign reverse manufacturing and reusable resources
recovery. This paper presents a web-based decision support and
evaluation system for operations in remanufacturing and recycling
including electronic product disassembly, materials recovery, and
recycling management. An overall evaluation of the product?s lifecycle
environmental impact considering EOL dispositions is also provided. The
system has been tested by a major computer manufacturer with computer
systems including desktop, laptop, and server. Comprehensive product
analysis and environmental impact assessment are discussed in the paper.
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Process and Facility Planning for Mobile Phone Remanufacturing
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G. Seliger (1), C. Franke, M. Ciupek, B. Basdere
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STC A, 53/1/2004, P.9
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Keywords: Mobile phone remanufacturing, linear optimization, discrete-event simulation |
Abstract : Successful remanufacturing of electric and electronic products
must meet the challenges of continuously falling prices for new
products, short life cycles, disassembly of unfriendly designs and
prohibiting costs in high-wage countries. Mobile phones are identified
as suitable products for profitable remanufacturing. A generic
remanufacturing plan for mobile phones is developed. For the planning of
remanufacturing capacities and production programs a linear optimization
model is introduced. In order to analyze the performance of the
remanufacturing facilities under consideration of uncertainties
regarding quantity and conditions of mobile phones, reliability of
capacities, processing times, and demand, discrete-event simulation is
applied. The simulation model is generated by an algorithm using results
from the linear optimization approach. The introduced method allows the
continuous adaptation of remanufacturing facilities under quickly
changing product, process, and market constraints.
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Development of a Productive Service Module Based on a Life Cycle Perspective of Maintenance Issues
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P.F. Cunha, J.A. Caldeira Duarte / L. Alting (1)
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STC A, 53/1/2004, P.13
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Keywords: Product life cycle management, Maintenance, Production planning |
Abstract : In this paper will be presented an ongoing research into the
functional integration of maintenance within the product life cycle,
based on experience obtained from work undertaken relating the
integration of maintenance with production planning. Taking into account
the needs of both production planning and maintenance systems, a
planning and control model, called a productive services module (PSM),
was developed. This module is able to manage the maintenance and
production functions while also accommodating the product reliability
forecasting, as an important input. The new model under development
integrates the history of production failures and its use is extended to
life cycle management of the production equipment.
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A precise visual control method for micromanipulator
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H.M. Wang, J.Y. Zhu (1)
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STC A, 53/1/2004, P.17
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Keywords: Object recognition, Visual control, Micromanipulator |
Abstract : A feature-based object recognition algorithm, which is robust
against occlusion, is presented. The subpixel accuracy can be obtained
by minimizing the sum of the distance between corresponding pixels of
template and image. In order to avoid the iterative adjustment and
complicated inverse solution of image jacobian, based on CMAC
(Cerebellar Model Articulation Controller) neural network, a feedforward
visual servo scheme is used to implement the mapping from the error
signal in the image space to the control signal in the task space.
Experimental result shows that precise positioning accuracy can be
obtained by using this method.
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Telepresence as a Solution to Manual Micro-Assembly
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G. Reinhart (2), S. Clarke, B. Petzold, J. Schilp
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STC A, 53/1/2004, P.21
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Keywords: Assembly, Man-Machine System, Telepresence |
Abstract : The progressive miniaturization and customization of today?s
products has lead to increased demand for manual micro-assembly systems.
Telepresence technologies provide a promising solution to manual
micro-assembly through overcoming scaling barriers and achieving high
accuracies, while offering flexibility and an intuitive human-controlled
working environment. Guaranteeing such an intuitive environment involves
the provision of adequate feedback information. Various physical sensor
arrangements at the micro-assembly site are used to generate haptic
feedback in the human-controlled environment. Non-physical or ?virtual?
sensors, although artificially generated, can also remarkably improve
user intuition. For precise controlling and high fidelity feedback,
telepresence environments also require a flexible communication platform
between the human operator and the assembly site.
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Integration of Product Design and Assembly Planning in the Digital Factory
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H. Bley (2), C. Franke
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STC A, 53/1/2004, P.25
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Keywords: Assembly planning, Process feature, Digital process planning |
Abstract : As assembly process planning fulfils the main function of
connecting product design to production simulation and thus, the
production system itself, a feasible software solution is needed to
support this process. Thus, a novel concept is presented that aims at
improving the integration of digital product design and assembly
planning by introducing a consistent data structuring. This approach
helps to reduce redundant tasks and supports the continuous data
exchange. It is based on the use of assembly features, i.e. pre-defined
geometry elements that contain additional technological information. The
prototypical implementation of the concept focuses on the use of
commercially available software tools, expanding them with additional
functionality for the application of assembly features. The
feature-based concept has been tested with a scenario from the
automotive supplier industry. For the considered assembly, a comparison
between the conventional and the feature-based planning approach is
presented in the paper. It points out that the major advantages of the
developed concept can be seen in an improved data concistency as well as
a higher level of efficiency within the planning activities.
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An Innovative Approach to the Automated Stacking and Grasping of Leather Plies
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F. Failli, G. Dini (1)
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STC A, 53/1/2004, P.31
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Keywords: Flexible part handling, Vacuum gripper, Ply separation |
Abstract : In this paper, a complete study of automatizing the
manipulation process of tanned natural leather plies is presented. The
considered leather plies are partially refined and their surface is
suitable for grasping by suction grippers. The particular features
(non-rigid structure, irregular shape and size, etc.) of such a material
make the handling and loading on the workstations very critical and
difficult to be approached. To increase the reliability of grasping, the
development of customized vacuum cups seems to be advisable. In the
paper, an innovative vacuum cup model is proposed. Its performances are
quantitatively compared with a other models by means of appropriate
measuring methods. Another problem concerning the automatic manipulation
of leather plies is to avoid the grasping of more than one ply at a
time, due to the irregularity of the ply profile. A device able to solve
this problem, using an innovative equipment for moving the entire stack
from the store to the workstation and for separating the plies, is also
shown and discussed.
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Innovative Assembly Concepts with Reel-to-Reel Transfer
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K. Feldmann (1), M. Boiger, T. Bigl, B. Zolleiss
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STC A, 53/1/2004, P.35
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Keywords: Assembly, Handling, Soldering |
Abstract : Mechatronic solutions are progressively influencing innovative
products from the most diverse range of applications. To ensure the
optimum integration of mechanical, electronical and software components
to form complete systems, modules are increasingly being based on
flexible circuit carriers. Despite technological advantages, the use of
foil based electronic circuits in main stream manufacturing has not
arisen due to the absence of suitable production technologies. This
article presents various concepts and prototype solutions to realize an
economic process with the main focus on automated reel-to-reel
manufacturing. The substrates are rigidly coupled in a panel during the
paste application, assembly and reflow process steps and are separated
at the end of the complete process sequence. This procedure requires
both innovative systems and processes and new concepts for controlling
the whole line.
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Continuous Failure Diagnosis for Assembly Systems using Rough Set Approach
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K. Mannar, D. Ceglarek (2)
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STC A, 53/1/2004, P.39
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Keywords: Assembly, Diagnostics, Rough Sets |
Abstract : Increasingly, companies require faster ramp-up in order to
cope with shorter production cycles and greater demand for product
variety. Since quality and dimensional problems are one of the major
reasons for delay during ramp-up, rapid diagnosis of dimensional
failures is of critical concern. Given the lack of historical data and
incomplete process knowledge in ramp-up, a Rough Set based diagnosis
methodology is proposed which focuses on developing: (1) Self-learning
ability to detect new faults as a system undergoes adjustments; and (2)
A continuous diagnostic for faults rather than a crisp definition of
faults. A case study illustrates the proposed approach.
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AREM Shop Evaluation Method
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T. Suzuki (3), T. Ohashi (3), M. Asano / T. Arai (1)
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STC A, 53/1/2004, P.43
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Keywords: Assembly, Defect, Productivity |
Abstract : A new tool has been developed to evaluate the reliability of
assembly shop operation. It is a subsystem of AREM (Assembly Reliability
Evaluation Method) [1] that can evaluate assembly fault occurrence rates
by using product design information. This new tool uses approximately
forty questions to assess quantitatively the influence of assembly shop
operation reliability on assembly fault occurrence. This method is being
used both to improve shop operation reliability and to select preferable
shop, and is proven to be effective. The entire AREM system supports
efficiently systematic improvement in assembly quality by examining both
product design and assembly shop.
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STC C |
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A New Approach to Cutting Temperature Prediction Considering the Thermal Constriction Phenomenon in Multi-layer Coated Tools
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M.H. Attia, L. Kops (1)
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STC C, 53/1/2004, P.47
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Keywords: Cutting, Tool coating, Thermal constriction resistance |
Abstract : A novel approach to the prediction of cutting temperature in
multi-layer coated tools is presented. This approach considers the
contact mechanics at asperity level and resulting thermal constriction
resistance phenomenon. Micro-contact model was developed and the
correlation between contact pressure and thermal constriction resistance
of uncoated and multi-layer coated tools is established. The thermal
interaction and redistribution of heat between the workpiece, the chip
and the tool were analyzed, supported by FE model, which considers
thermal characteristics of multi-layer coating. The results indicate
that the tool coating may cause significant reduction in heat flowing
into the tool.
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Repeatable On-the-Machine Cutting-Edge-Forming Technology Applying Composite Electroplating and Anodic Electrolysis
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K. Kurahashi, K. Yanagihara, Y. Tani (2), H. Sato (1)
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STC C, 53/1/2004, P.53
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Keywords: Cutting, Edge, Electro-plating |
Abstract : If a cutting tool could be repeatedly formed without removal
from a machine utilized in a cutting process, it would be highly
beneficial in that it could reduce not only any positioning error due to
a tool exchange, but also the consumption of scarce tool materials and
energy. Composite electroplating to build up the cutting edge and anodic
electrolysis to remove the worn-out plated layer, are utilized to
realize this concept. Employing these processes, an on-the-machine
edge-forming device has also been designed. The results of experiments
indicate that, the device can complete all the processes within 4
minutes, and that the plated tools are able to cut JIS S45C (ISO C 45)
steel.
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Thermo-Chemical Wear Mechanism of Diamond Tool in Machining of Ferrous Metals
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S. Shimada (2), H. Tanaka, M. Higuchi, T. Yamaguchi, S. Honda, K. Obata
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STC C, 53/1/2004, P.57
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Keywords: Cutting, Diamond turning, Tool wear |
Abstract : To understand the wear mechanism of diamond tool in machining
of ferrous metals, an erosion test simulating wear process and ab-initio
molecular orbital calculation are carried out. The results of the tests
and analyses show that the essential wear mechanism at the temperature
higher than 1000K is the dissociation of carbon atoms on diamond surface
due to the interaction with iron surface. The wear rate is controlled by
the removal rate of dissociated carbon atoms from the tool-work
interface such as diffusion into workpiece. At the temperature lower
than 900K, the mechanism involves the removal of carbon atoms due to
oxidization of diamond accompanied with deoxidization of iron oxide.
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Multifunctional Application of a Synthetic Ester to Machine Tool Lubrication Based on MQL Machining Lubricants
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S. Suda, T. Wakabayashi, I. Inasaki (1), H. Yokota
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STC C, 53/1/2004, P.61
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Keywords: Cutting, Fluids, Environment |
Abstract : Machine tools generally necessitate a variety of lubricants.
Since some of those lubricants are often contaminated with cutting
fluids and disposed without adequate separation treatments, it must
certainly be convenient to prepare a multifunctional fluid applicable to
both machining and other lubricating parts. In minimal quantity
lubrication (MQL) machining, synthetic polyol esters are the successful
cutting lubricant. This study therefore proposes a certain synthetic
ester as a base candidate of environmentally friendly multifunctional
fluids. Several cutting and lubrication tests have demonstrated the
successful multifunctional lubrication performance of this ester with a
very small quantity of a highly effective additive.
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Turning and Drilling of NiTi Shape Memory Alloys
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K. Weinert (1), V. Petzoldt, D. Kötter
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STC C, 53/1/2004, P.65
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Keywords: Nickel Titanium, Process Design, Shape Memory Alloy |
Abstract : Shape memory alloys based on NiTi have a high potential for a
large variety of applications. This functional material is very
difficult to machine because of its high ductility, its different shape
memory properties in dependence on temperature and the strong work
hardening when this material is deformed. This paper presents the
process design for producing a pipe coupling from NiTiNb. The design is
based on experiments regarding turning and drilling of the intermetallic
compound NiTi. The influence of the cutting tool material on the
machining process was evaluated. As a result of the experiments, the
metal removal rate was increased significantly and the tool life could
be extended while at the same time ensuring a high work piece quality.
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High Speed Face Milling of a Aluminium Silicon Alloy Casting
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E-G. Ng, D. Szablewski, M. Dumitrescu, M.A. Elbestawi (1), J.H. Sokolowski
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STC C, 53/1/2004, P.69
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Keywords: Face milling, Aluminium silicon alloy, High speed machining |
Abstract : High speed machining of aluminium silicon alloy castings has
gained significant interest from automotive industry involved in the
development of the new generation of lightweight vehicles. This paper
investigates the influence of workpiece microstructure, namely the
secondary dendritic arm spacing (SDAS), tool material and geometry on
tool wear mechanisms, cutting forces and surface integrity when face
milling at cutting speeds of 5,000 m/min¯?. It was found that the SDAS
is the parameter with the main influence on tool wear rate; higher SDAS
values require polycrystalline diamond (PCD) tooling due to the lower
wear rates when compared with carbide tools. Finite Element Analysis
(FEA) was employed to study the influence of tool wear on temperature
and shear stress distribution in the workpiece material.
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Efficient Tool Paths and Part Orientation for Face Milling
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A. Rangarajan, D. Dornfeld (1)
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STC C, 53/1/2004, P.73
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Keywords: Planning, Face milling, Toolpath |
Abstract : High speed machining is pushing the limits of feeds and
speeds. A different approach for high throughput is described here. The
focus is on the maximum feed that can be obtained for a segment; the
feed rate losses due to sharp corner changes in tool path are minimized.
The interdependency of individual axis drive speeds for a tool path
segment are analyzed. There exists an optimum work angle relative to the
axes that reduces losses and increases allowable feeds for particular
segments, saving valuable cycle time and balancing feed drive loads.
Face milling and roughing steps of end milling are the most attractive
application areas.
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An Optimum Two-tool Solution for Milling 2?D Features from Technological and Geometric Viewpoints
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S. Hinduja (1), D. Sandiford
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STC C, 53/1/2004, P.77
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Keywords: Milling, Optimisation, Cutting tools |
Abstract : This paper describes a procedure to determine the optimum pair
of tools that can machine a milling feature with soft and/or hard
boundaries. The optimum cutting conditions, as well as the actual
distances traversed by the two tools, are used in the determination of
the total machining cost. In addition to technological constraints such
as machine tool power, geometrical constraints including minimum concave
radius, bottleneck width and entry distance are determined from the
Voronoi diagram. The paper also describes a novel method to determine
the stock machined by the larger tool. An example is included to
illustrate the method.
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Milling Performance of Coated Inserts with Variable Coating Thickness on their Rake and Flank
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K.-D. Bouzakis (1), S. Hadjiyiannis, G. Skordaris, I. Mirisidis, N. Michailidis, D. Koptsis, G. Erke
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STC C, 53/1/2004, P.81
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Keywords: PVD coating, coating thickness distribution, cutting performance |
Abstract : During the Physical Vapour Deposition of coatings, the
orientation of cemented carbides insert surfaces to the plasma flux
direction affects the occurring film thickness distribution on the rake
and flank, which in turn might influence the wear propagation in cutting
processes. In the present paper the cutting performance in milling of
PVD coated cemented carbides inserts with variable film thickness on the
rake and flank is introduced and with the aid of FEM-supported
calculations explained. The investigation results revealed that a
thicker film on the tool rake in comparison to the existing one on the
flank and moreover a thick and uniformly deposited film in the cutting
wedge region significantly enhances the cutting performance in milling.
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A Predictive Relationship between Forces, Surface Finish and Tool-life
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B.N. Colding (1)
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STC C, 53/1/2004, P.85
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Keywords: Machinability, Methodology, New Discovery |
Abstract : After 50 years of metal cutting research the author discovered
a unique and reliable relationship between specific energy and tool-life
and surface finish, based on a novel shear angle relationship as a
function of tool-life. Quantitative values on tool-life, cutting forces
and finish are provided by a system of equations for turning, milling,
drilling and grinding, covering a large range of tool geometries, feeds
and cutting speeds. This discovery, proven by hundreds of sets of
experimental data, will assist researchers planning and interpreting
experiments as well as facilitate for industry to obtain reliable
machining data.
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An Energy Based Analytical Force Model for Orthogonal Cutting of Metal Matrix Composites
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H.A. Kishawy, S. Kannan, M. Balazinski (1)
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STC C, 53/1/2004, P.91
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Keywords: Cutting, Composite, Specific energy |
Abstract : The machining of metal matrix composite (MMC) presents a
significant challenge to the industry. The hard and abrasive nature of
the reinforcement causes rapid tool wear and high machining cost.
Cracking and debonding of the reinforcement particles are the
significant damage modes that directly affect the tool performance. This
paper presents, an energy based analytical force model that has been
developed for orthogonal cutting processes. The total specific energy
for deformation has been estimated along with the energy consumed for
debonding as a function of volume fraction and material properties.
Orthogonal cutting tests were carried out for a range of different feeds
on different matrix materials and volume fractions. The results showed
good agreement between the predicted and measured cutting forces.
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Modelling the Effects of Flank Wear Land and Chip Formation on Residual
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L. Chen (2), T.I. El-Wardany, W.C. Harris
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STC C, 53/1/2004, P.95
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Keywords: Surface, Titanium, Residual stress, Cutting, Finite element method (FEM) |
Abstract : The selection of optimum machining parameters and tool
geometry for difficult to cut materials used in aerospace applications
is usually controlled by the quality and integrity of the surface
produced, the burr formation and the part distortion. In this paper, a
finite element model is developed to simulate the effects of tool flank
wear and chip formation on residual stress when orthogonal cutting
Ti-6Al-4V. A crack propagation module is also developed and incorporated
into the finite element solver to accurately simulate the segmental
chips produced during machining of titanium. The predicted results
emphasize the importance of modelling the chip formation mechanism and
tool wear correctly because of their effect on the cutting forces and
temperature field. This subsequently influences the magnitude and
distributions of the residual stress. Good correlation was obtained
between measured and predicted residual stress distribution.
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A Model for Surface Roughness in Ultraprecision Hard Turning
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M.M.W. Knuefermann (3) / P.A. McKeown (1)
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STC C, 53/1/2004, P.99
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Keywords: Hard Turning, Surface Roughness, Modelling |
Abstract : Numerical modelling procedures to predict surface roughness in
turning processes have been in use for more than forty years. However,
the procedures available to date do not correlate well with hard
turning. A novel numerical model is presented which incorporates process
disturbances such as tool cutting edge defects and machine vibration in
hard turning and thus their effect on the achievable surface roughness.
It includes a material partition equation to address the behaviour of
chip removal and deformations during the cutting process; it also allows
additional information to be derived about the mechanism of generation
involved at a given point on the surface. Experimental results show good
correlation of calculated with measured roughness parameters even at low
feed rates.
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Improving Cycle Time in Sculptured Surface Machining Through Force Modeling
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E. Budak (2), I. Lazoglu, B.U. Guzel
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STC C, 53/1/2004, P.103
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Keywords: End Milling, Force, Feed rate Scheduling |
Abstract : In this paper, an enhanced mathematical model is presented for
the prediction of cutting force system in ball end milling of sculptured
surfaces. This force model is also used as the basis for off-line feed
rate scheduling along the tool path in order to decrease the cycle time
in sculptured surface machining. As an alternative for setting a
constant feed rate all along the tool path in rough machining of
sculptured surfaces, resultant cutting forces are aimed to be kept under
a pre-set threshold value along the tool path by off-line scheduled
piecewise variable feed rates. In this paper, it is shown that machining
time, depending on complexity of sculptured surfaces, can be decreased
significantly by scheduling feed rate along the tool path. The model is
tested under various cutting conditions and some of the results are also
presented and discussed in the paper.
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Determination of the Machining Characteristics of a Biomaterial Using a Machine Tool Designed for Total Knee Arthroplasty
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M. Mitsuishi (2), S. Warisawa, N. Sugita
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STC C, 53/1/2004, P.107
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Keywords: Biomedical material cutting, Machinability, Cutting force analysis |
Abstract : The authors have developed a prototype of a sophisticated
9-axis machine tool for bone cutting to reduce the machining error in
cutting bone to accept artificial joint replacements and to improve the
postoperative performance of the implants. It is necessary to determine
the machining characteristics of the bone to optimize the cutting state.
In this paper, model bones with mechanical characteristics similar to
those of human bone and pig bone, were endmilled. The relationship
between the cutting conditions and the cutting characteristics of
cortical bone and cancellous tissue, of which bone is comprised, were
evaluated.
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STC Dn |
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'What-if' design: a synthesis method in the design process
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D. Lutters, T.H.J. Vaneker, F.J.A.M. van Houten (1)
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STC Dn, 53/1/2004, P.113
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Keywords: Information management, design support system, 'what-if' design |
Abstract : In integrating functions, information and control in the
design and engineering cycle, the information content acts as a
facilitator, whereas the processes involved actually effectuate the
results of the development cycle. As combining processes in an effective
and efficient manner becomes increasingly feasible, a more dynamic
coherence between the processes involved is implied, calling for
different control principles, whilst maintaining ?and possibly
increasing? flexibility. This increases the competency in understanding
and utilising consequences of design decisions. Based on this, a
?what-if? design support system can help in performing routine tasks and
aiding designers and engineers in understanding more complex challenges.
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Abstraction of Biological Analogies for Design
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T.W. Mak, L.H. Shu (2)
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STC Dn, 53/1/2004, P.117
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Keywords: Conceptual design, information, biomimetic design |
Abstract : Biomimetic design uses biological analogies to inspire design
concepts. This paper describes a study on selecting and using relevant
biological phenomena for design. A hierarchy of forms, behaviors and
principles classifies how biological phenomena are presented as
potential analogies. The type of similarity achieved between biological
phenomena and resulting concepts is affected by the types of information
presented in the descriptions of the phenomena. Results suggest that
concepts based on strategically similar analogies occur more frequently
in the presence of principles that explain the biological phenomena,
rather than descriptions of phenomena that focus on forms and behaviors.
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Agent Based Negotiation for Collaborative Design Decision-Making
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Y. Jin, S.C-Y. Lu (1)
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STC Dn, 53/1/2004, P.121
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Keywords: Design, Decision-making, Agent |
Abstract : Complex design involves trade-offs and teamwork. To make
collaborative design decisions, designers must negotiate with each other
to resolve their discrepancies through exploring the design space,
generating new ideas and compromising for agreement. Advances in
negotiation research have been made in social psychology, distributed
artificial intelligence, and decision theory. But few have been applied
to design. Built on existing negotiation research, we are developing an
agent based negotiation framework to support collaborative design
decision-making. This paper presents the negotiation protocol,
information models, and negotiation strategies of the framework followed
by discussion of an application case example.
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Mathematical transforms in design: Case study on feed-back control of a customizable automotive suspension
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H.V. Deo, N.P. Suh (1)
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STC Dn, 53/1/2004, P.125
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Keywords: Axiomatic Design, Suspension system, Feedback |
Abstract : Engineering design and analysis is replete with examples of
mathematical transforms. This paper discusses the use of mathematical
transforms at the operational stage implemented by superimposing the
system with a control system to (1) convert a decoupled or coupled
system to uncoupled, (2) achieve robustness to noise factors and (3)
eliminate imaginary complexity. This paper proves with examples that
such controller design and implementation is much easier for an
uncoupled or decoupled design as compared to a coupled design. The case
study presents a new customizable automotive suspension with independent
control of stiffness, damping and ride-height. This system was proposed,
designed and built using axiomatic design principles. The mechanical
design is decoupled with respect to the functional requirements (FRs) of
stiffness and ride-height; moreover ride-height is affected by the load
on the vehicle (noise factor). This paper presents the design and
implementation of a feedback control system for the customizable
suspension to uncouple the system and to make it robust to the noise
factor.
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A New Approach for Robust Design of Mechanical Systems
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P. Gu (2), B. Lu, S. Spiewak (2)
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STC Dn, 53/1/2004, P.129
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Keywords: Product design, Robust design, Axiomatic design |
Abstract : Robust product design aims to develop a product that satisfies
design requirements while ensuring minimal effects of environmental
variability on product performance. Environmental variations may come
from raw materials, manufacturing processes, and/or operational
environments, which can cause deviations of product functions. This
research can verify that the independence axiom can lead to a ro-bust
design, while robust designs do not necessarily require functional
independence. Thus, designs can be divided into three categories -
feasible designs, robust designs and ideal designs. In the first level
of the design process, the designers should generate a feasible design,
then seek to acquire robustness, and finally determine the possibility
of independence. Axiomatic design aims to achieve the independent
design; the traditional robust design is an experimental method that may
not reach design independence. The proposed approach introduces the
integration of the independent analysis that is based on axiomatic
design, with the robust analysis that is based on the traditional robust
technique. It can help the designer to seek an ideal design or a robust
design in respect to the specific design conditions.
|
|
Adaptive Modelling and Simulation of Product Development Processes
|
|
F.-L. Krause (1), C. Kind, J. Voigtsberger
|
|
STC Dn, 53/1/2004, P.135
|
|
Keywords: Product development, Process simulation, Petri net |
Abstract : A tool for modelling and simulation of product development
processes has to be able to map the specific stochastic behaviour of
these processes. Taking this into consideration, the paper presents an
approach to adaptive modelling and simulation using Petri nets. New to
this approach is that the process model is generated dynamically at
simulation run time. Based on the effective premises and boundary
conditions, generic processes are selected, parameterised, and
integrated as an instance into the model. Thereby, the model is adapted
to its present state at simulation run time. This enhances the quality
of the simulation results.
|
|
An artificial intelligence approach to the registration of free-form shapes
|
|
L.M. Galantucci (2), G. Percoco, R. Spina
|
|
STC Dn, 53/1/2004, P.139
|
|
Keywords: Reverse Engineering, Computer Aided Inspection, Alignment |
Abstract : Registration, defined as the process of matching geometric
entities, is performed when multiple scanned data sets must be aligned
or when an existing model must match digitized point clouds. This
process is crucial in several applications such as Reverse Engineering,
CAD-based inspection and computer vision. The goal of this process is
the computation of the optimal rigid transformation for the alignment of
several sets of geometric entities (points and/or surfaces).
Registration is generally performed by using a two-step procedure
necessary to realize coarse and fine alignments. Human intervention is
normally required for coarse registration while fine registration is
usually a semi-automatic procedure. Consequently alignment is not
usually a single step automatic operation and is also affect by errors.
In this paper the authors propose a hybrid approach for automatic
registration applied to free-form shapes. This hybrid approach employs a
asynchronous data communication between an Artificial Neural Network and
Genetic Algorithms. The Neural Network performs the coarse alignment
giving an initial solution for the registration operation which is then
performed by Genetic Algorithms to minimize error deviations between
geometrical entities. Several case studies have been investigated in
order to validate the proposed approach.
|
|
Multiresolution Representation of 2D CSG Models
|
|
L. Peled, A. Fischer (1), M. Shpitalni (1)
|
|
STC Dn, 53/1/2004, P.143
|
|
Keywords: Computer Aided Design (CAD), Multiresolution, CSG Geometric Modeling |
Abstract : Multiresolution is currently one of the main schemes used in
CAD modeling for representing objects, particularly when large-scale
geometric data must be transferred interactively over a network, as in
the case of collaborative design. Increasingly complex products and
growing competition have turned design into a collaborative team effort.
Furthermore, the widespread development of Internet viewers has also
necessitated the transfer and display of large-scale CAD models over
networks. In order to reduce the volume of transferred data, efforts
have been made to transfer CSG (Constructive Solid Geometry) models
rather than those based on B_rep (Boundary Representation). This paper
presents an original new method for speeding up data transfer by using
multiresolution CSG models at different levels of details (LOD). The
multiresolution CSG algorithm generates a hierarchy of multiresolution
CSG trees; at each level, the shape is further approximated and
represented by a smaller number of CSG primitives. The paper analyzes
the proposed algorithm, and demonstrates its feasibility.
|
|
Capturing Expert Knowledge for Supporting Design and Manufacturing of Injection Molds
|
|
F. Kimura (1), H. Ariyoshi, H. Ishikawa, Y. Naruko, H. Yamato
|
|
STC Dn, 53/1/2004, P.147
|
|
Keywords: CAD/CAM, Mold, Knowledge based system |
Abstract : Knowledge based approach is effective for renovating design
and manufacturing processes. The objective of this paper is to
investigate roles and usages of expert engineering knowledge in
high-quality manufacturing, and to study a practical knowledge capturing
method for realizing engineering support tools. An engineer oriented
interface for a capturing method is proposed, and a flexible
representation framework is studied for various types of expert
knowledge. An integrated knowledge-based system has been developed for
mold design support. The results have been evaluated by design and
manufacturing of molds for cellular phones, and have shown substantial
reduction of lead time for mold production.
|
|
An approach to Life Cycle Oriented Technical Service Design
|
|
J.C. Aurich, C. Fuchs / M.F. DeVries (1)
|
|
STC Dn, 53/1/2004, P.151
|
|
Keywords: Life Cycle Engineering, Design Process, Technical Service Design |
Abstract : The importance of technical, i.e. product related services has
significantly increased over the past years. Traditionally, technical
services are provided during product usage. In light of the potential
impact of technical services on the entire product life cycle, the
application of life cycle engineering techniques to service design is
suggested. Consequently, the presented research work aims at developing
a service design process. Based on three main strategies for combining
products with related services, a corresponding design process is
proposed. It simultaneously considers the product, process and
information dimensions of services.
|
|
End-of-Life-Based Negotiation Throughout the Design Process
|
|
D. Brissaud (2), P. Zwolinski
|
|
STC Dn, 53/1/2004, P.155
|
|
Keywords: Design, Life Cycle, Eco-design. |
Abstract : The aim of this paper is to suggest a methodology to
accommodate a preferred end-of-life scenario in the early phases of a
product. Life-cycle engineering and DFE methods have tried to improve
design from an environmental point of view. But they failed to provide
product designers with both levers on usable product characteristics and
strategic objectives. The situation-based approach proposed focuses on
negotiation of end-of-life strategies and their impact on product
characteristics throughout the product development phase. It is based on
the way negotiation between product engineer and end-of-life strategy
engineer can be prepared, then performed and controlled
|
|
Knowledge Brokering for Assisting the Generation of Automotive Product Design
|
|
K.K.B. Hon (1), J. Zeiner
|
|
STC Dn, 53/1/2004, P.159
|
|
Keywords: Product, Knowledge, Design |
Abstract : The aim of this paper is to present a pragmatic model for the
systematic transfer of ideas and knowledge at the early stage of product
design in a company environment. In using the model, the basic premise
is not to build a new product ?from scratch? but to reuse existing ideas
and knowledge from other objects and products developed previously. This
new approach is called Knowledge Brokering (KB). The developed KB model
consists of four sequential steps, which cover the collection and
clustering of explicit design knowledge, the systematic learning
process, retention and transfer of tacit design knowledge. The premises
for using the KB model and case study results from the automotive
industry on the advantages and limitations of the new approach are also
described.
|
|
Shared dynamic entities technology to support distant coordination in design activity
|
|
F. Noël, S. Tichkiewitch (1)
|
|
STC Dn, 53/1/2004, P.163
|
|
Keywords: Design, Coordination, Negotiation |
Abstract : The coordination of design systems is based on various
coordination modes. Prescriptive activity sequences and negotiation
around intermediary objects are complementary approaches to solve this
issue. Both are involved in real design projects. Models to support this
global coordination are often centred on one of the two approaches.
Indeed models are rarely complete enough to handle all the complexity of
both. This paper focuses on a quite new technology providing the
opportunity to build a model simultaneously to its instantiation. This
technology, based on the concept of dynamic entities, is adapted to be
shared between designers working from remote areas. Then we propose to
use this technology to support coordination design in distributed
organisations. Dynamic entities provide a way to complete and adapt a
model according to the continuously negotiated context and free the
system for being configured on very specific design modes.
|
|
Release-Engineering ? An Approach to Control Rising System-Complexity
|
|
G. Schuh / W. Eversheim (1)
|
|
STC Dn, 53/1/2004, P.167
|
|
Keywords: Optimisation, Productivity, Complexity Management |
Abstract : This paper presents an innovative approach to
augment R&D effectiveness and manage increasing system complexity.
Release-Engineering is a principle of software engineering which can be
transferred to complex automotive systems. Simulations based on features
show significant reduction of internal complexity. Without reduction of
necessary marketwise diversity, a time wise bundling of component
changes exponentially lowers system complexity. The approach represents
a major step towards more significant innovation programmes through
suitable, dedicated R&D efforts on system variants. Another meaningful
implication of Release-Engineering is its impact on innovation frequency
by providing significant increases in innovation rates.
|
STC E |
|
Composite Wires with High Tensile Core for Wire EDM
|
|
J.-P. Kruth (1), B. Lauwers (2) , B. Schacht, J. Van Humbeeck
|
|
STC E, 53/1/2004, P.171
|
|
Keywords: Wire EDM, Steel wire, Accuracy |
Abstract : In recent years wire EDM cutting speeds and final surface
roughness have been continuously improving. Much higher cutting speeds
during roughing and surface roughness values lower than 0.1 µm Ra during
finishing can be obtained. These enhancements are mostly attributed to
the use of more advanced generator technology, but also to the type of
wire. This paper discusses the use of new composite wires comprising a
high tensile core and several coatings. Several wire compositions are
introduced and experimentally tested. The use of a very high tensile
core, the application of a layer that prevents the process heat from
weakening the wire core and the presence of a superficial top coating
with different possible functions are discussed. Results obtained while
cutting with prototype wires show that a significant rise in accuracy
especially in corner cutting is attained, while the cutting rate is at a
comparable level as commercial reference wires.
|
|
Chemical Assisted Laser Machining for the Minimisation of Recast and Heat Affected Zone
|
|
L. Li (2), C. Achara
|
|
STC E, 53/1/2004, P.175
|
|
Keywords: laser, machining, quality |
Abstract : Laser processing techniques have been widely used for high
speed, high accuracy subtractive manufacturing such as cutting,
drilling, milling and micro-machining. Most of these processes are based
on thermal mechanisms. For the machining of metallic materials, a layer
of recast and heat affected zone is normally present on the
laser-machined components. This paper reports a novel technique that
aims to minimize such heat affects and at the same time to improve the
material removal efficiency. A relatively environmentally friendly salt
solution, in contact with the beam-material interaction point, was used
in this study to enable material removal to be based on laser activated
thermal-chemical mechanism. It has been shown that, not only the recast
layer can be removed during the processing, the material removal rate
can be increased up to 300%37; for 316 stainless steel work piece.
|
|
Modelling and Experimental Investigation of Laser Assisted Jet Electrochemical Machining
|
|
A.K.M. De Silva (2), P.T. Pajak, D.K. Harrison, J.A. McGeough (1)
|
|
STC E, 53/1/2004, P.179
|
|
Keywords: Electro-chemical machining, Laser, Localised dissolution |
Abstract : Laser Assisted Jet Electrochemical Machining is a hybrid
process which combines a relatively low power laser(375mW) with an
electrolyte jet to facilitate metal removal. The main purpose of the
laser is to enhance the localisation effect of electrochemical
dissolution from the workpiece, thus giving better precision and
machining efficiency. The laser thermally activates the material surface
where it impinges thereby increasing the electrochemical current density
in that localised zone. A theoretical model is used to explain the
effects of localisation of electrochemical dissolution process.
Experimental analysis using aluminium alloy and stainless steel has
proved that laser assistance can yield up to 54%37; higher volumetric rate
and up to 38%37; better accuracy than using electrolytic jet alone.
|
|
Improvement of Dry EDM Characteristics Using Piezoelectric Actuator
|
|
M. Kunieda (2), T. Takaya, S. Nakano
|
|
STC E, 53/1/2004, P.183
|
|
Keywords: EDM, dry process, piezoelectric actuator |
Abstract : This paper describes improvement of the machining
characteristics of dry electrical discharge machining (dry EDM) by
controlling the discharge gap distance using a piezoelectric actuator.
Dry EDM is a new process characterized by small tool electrode wear,
negligible damage generated on the machined surface, and significantly
high material removal rate especially when oxygen gas is used. However,
the narrow discharge gap length compared with conventional EDM using oil
as the dielectric working fluid results in frequent occurrence of short
circuiting which lowers material removal rate. A piezoelectric actuator
with high frequency response was thus introduced to help control gap
length of the EDM machine. To elucidate the effects of the piezoelectric
actuator, an EDM performance simulator was newly developed to evaluate
the machining stability and material removal rate of dry EDM.
|
|
Investigation of Femtosecond Laser-assisted Micromachining of Lithium Niobate
|
|
A. Malshe, D. Deshpande, E. Stach, K. Rajurkar (1), D. Alexander
|
|
STC E, 53/1/2004, P.187
|
|
Keywords: Laser micro machining, single crystal, surface |
Abstract : Lithium Niobate has a potential for applications in
electronics and communication industries due to its unique
electro-optical, piezoelectric and nonlinear properties. Femtosecond
laser machining offers the best alternative to machine the mechanically
fragile and optically delicate lithium niobate crystal. This paper
reports a study of the effect of femtosecond laser machining on the
surface integrity of lithium niobate. The transmission electron
microscopy reveals a 100nm thin amorphous region and a void. The
chemical analysis shows a loss of lithium and oxygen from the surface
and sub-surface. Optical illumination facilitates the selective readout
of the written spots of 2 microns size.
|
|
Mapping and modelling single scan track formation in direct metal selective laser melting
|
|
T.H.C. Childs (1), C. Hauser, M. Badrossamay
|
|
STC E, 53/1/2004, P.191
|
|
Keywords: Laser, Sintering, FEM |
Abstract : When a laser beam scans the surface of a metallic powder bed,
the resulting track may be continuous with a crescent shape
cross-section, continuous with an elliptical section, discontinuously
irregularly broken, discontinuously balled or only partially melted.
This paper reports experimental observations of what CO2 laser powers
and scan speeds lead to what type of track, for M2 and H13 tools steels
and 314S stainless steel powder beds. It also presents measurements of
bed physical properties relevant to predicting the behaviour and the
results of modelling that agree with the experiments. The results are
placed in the broader context of selective laser melting build strategies
|
|
Residual Stress within Metallic Model Made by Selective Laser Melting Process
|
|
M. Shiomi, K. Osakada (1), K. Nakamura, T. Yamashita, F. Abe
|
|
STC E, 53/1/2004, P.195
|
|
Keywords: Prototyping, Stress, Selective Laser Melting (SLM) |
Abstract : In order to improve the mechanical properties and the
dimensional accuracy of the steel model produced by the selective laser
melting process, the distribution of residual stress within the model is
measured, and some methods for reducing the residual stress are
proposed. The experimental results show that a large tensile stress
remains in the surface layer of the model. Heat treatment at 600 and 700
° C for one hour reduces the residual stress effectively by about 70 %37;.
Re-scanning of laser and heating of the powder bed decrease the tensile
stress by 55 %37; and 40 %37;, respectively.
|
|
-2004UV-laser assisted fabrication of integrated-optical waveguides
|
|
F. Vollertsen (2), C. Wochnowski
|
|
STC E, 53/1/2004, P.199
|
|
Keywords: polymer, optical chip, excimer laser |
Abstract : By UV-laser-irradiation a controllable change of the
refractive index of some polymers can be attained in the irradiated
zone. The detailed UV-photon-induced process mechanisms have been
investigated on the basis of PMMA employed as an UV-modifiable model
polymer. By mask lithographic methods the UV-laser-assisted technology
for the modification of the polymer optical properties enables the local
increase of the refractive index and thus the fabrication of
integrated-optical waveguiding elements in the surface of a planar
polymer chip. These elements are relevant for the manufacturing of
complex integrated-optical components. The optical and functional
properties of the integrated-optical waveguides have been characterized.
|
STC F |
|
Forming strategies and Process Modelling for CNC Incremental Sheet Forming
|
|
G. Hirt, R. Kopp (1), J. Ames, M. Bambach
|
|
STC F, 53/1/2004, P.203
|
|
Keywords: Forming, Sheet metal, Kinematic |
Abstract : Incremental Sheet Forming (ISF) is a process capable of
producing complex sheet components by the CNC movement of a simple tool
in combination with simplified dies. Earlier work revealed two major
process limits, namely the limitation on the maximum achievable wall
angle, and the occurrence of geometric deviations. The work detailed in
this paper focuses on forming strategies to overcome these process
limits, including the processing of tailor rolled blanks. Additionally,
finite element modelling of the process is presented and discussed with
respect to the prediction of the forming limits of ISF.
|
|
Influence of mechanical properties of the sheet material on formability in single point incremental forming
|
|
L. Fratini, G. Ambrogio, R. Di Lorenzo, L. Filice, F. Micari (1)
|
|
STC F, 53/1/2004, P.207
|
|
Keywords: Formability, Progressive Forming, Statistical Analysis |
Abstract : New trends in sheet metal forming are rapidly developing and
several new forming processes have been proposed to accomplish the goals
of flexibility and cost reduction. Among them single point incremental
forming operations, in which the final shape of the component is
obtained by the relative movement of a simple and small punch with
respect to the blank, appear quite promising. In the paper, material
formability issues in incremental forming were studied. Some relevant
correlations among material formability and other mechanical properties
of the material were analysed. The FLD0 value, i.e. the major strain at
fracture in plane strain conditions, was determined for different
materials and the influence of the main material parameters on
formability was accurately investigated through a statistical analysis.
|
|
Analysis of Residual Stresses in High-Pressure Sheet Metal Forming
|
|
M. Kleiner (2), R. Krux, W. Homberg
|
|
STC F, 53/1/2004, P.211
|
|
Keywords: Residual stress, Deep drawing, Sheet metal hydroforming |
Abstract : The further development of innovative forming processes like
sheet metal hydroforming is only possible with the help of detailed
knowledge about the workpiece properties and their formation depending
on the particular process strategy. Up to now, the detailed
understanding regarding the formation of residual stresses in
hydroforming processes like the high-pressure sheet metal forming (HBU)
is insufficient. Therefore, numerical (FEM) and experimental
investigations on the residual stresses induced in HBU-formed workpieces
have been carried out. The results show that a higher fluid pressure
leads to significantly lower residual stresses in addition to an
improved accuracy of form and dimensions.
|
|
Improvement of Formability by Oscillation of Internal Pressure in Pulsating Hydroforming of Tube
|
|
K. Mori (2), A.U. Patwari, S. Maki
|
|
STC F, 53/1/2004, P.215
|
|
Keywords: Tube, Finite element method, Hydroforming |
Abstract : A new history of internal pressure in the hydroforming
processes of tubes is developed to attain high formability. The effect
of improvement of formability by the oscillation of internal pressure in
a pulsating hydroforming process of tubes is examined using both finite
element simulation and experiment. The deformation behaviour during the
hydroforming is greatly affected by the oscillation of internal
pressure. For a monotonic history of small internal pressure, the
wrinkling was caused by insufficient bulging, whereas the necking and
bursting occurred for a monotonic history of large internal pressure.
The occurrence of these defects can be avoided by oscillating the
internal pressure in the pulsating hydroforming. The improvement of
formability in the pulsating hydroforming is due to both low pressure
and oscillation of pressure. The effects of the amplitude and cycle
number of pressure in the pulsating hydroforming on the deformation
behaviour are investigated. It is found the oscillation of internal
pressure is effective in preventing the occurrence of defects.
|
|
Anisotropy and formability of AA5182-0 aluminium alloy sheets
|
|
D. Banabic / K. Siegert (1)
|
|
STC F, 53/1/2004, P.219
|
|
Keywords: Forming, Sheet metal, Anisotropy |
Abstract : This paper presents a new yield criterion for orthotropic
sheet metals and it´s implementation in a theoretical model of the
Forming Limit Diagrams. The equivalent stress equation shows that the
shape of the yield surface is defined by eight material parameters. The
minimisation of an error-function has been used for the numerical
identification of these coefficients. The parameters are established in
such a way that the constitutive equation associated to the yield
surface reproduces the plastic behaviour of the actual material. The
uniaxial yield stresses (O0, ?O45, O90), biaxial yield stress (Ob),
uniaxial anisotropy coefficients (r0, r45, r90) have been used in
identification. The new yield criterion has been implemented in the
Marciniak-Kuczynski theory in order to predict the limit strains. The
theoretical Forming Limit Curves have been compared with the
experimental ones. The friction free tests, the hydraulic bulge test
(for the positive minor strains) and the tensile test for plane strain
and for uniaxial tensile test (for the negative minor strains) are used.
The predicted yield surface and Forming Limit Diagrams for AA5182-0
aluminium alloy sheets are in good agreement with the experimental ones.
|
|
Finite Element Simulation of Deep Drawing of Tailored Heat Treated Blanks
|
|
M. Geiger (1), M. Merklein, M. Kerausch
|
|
STC F, 53/1/2004, P.223
|
|
Keywords: deep drawing, finite element method (FEM), tailored heat treated blanks |
Abstract : Using a laser system for local heat treatment, it is possible
to adjust the mechanical properties of aluminum blanks in a restricted
area by influencing the precipitation structure to manufacture so called
Tailored Heat Treated Blanks (THTB). These blanks are characterized by a
distribution of the mechanical properties adapted particularly for the
forming conditions during deep drawing. This paper presents a finite
element (FE) based procedure to determine adequate laser parameters for
the heat treatment process to enhance the forming limits. Both FE and
experimental results show the improved process compared to the
conventional drawing of homogeneous aluminum blanks.
|
|
The influence from the punch land in backward can extrusion
|
|
J. Danckert (1)
|
|
STC F, 53/1/2004, P.227
|
|
Keywords: Extrusion, Aluminium, Punch |
Abstract : Backward can extrusion punches are commonly made with a
cylindrical punch land as also recommended by the ICFG. The contact
forces on the punch land have been determined using the slab analysis
method and FEM. The results show that a slight tilt of the punch land
changes the contact conditions between punch land and can wall causing
on the punch a net force, which will deflect the punch off centre
leading to variations in wall thickness. A new punch design is proposed
in which the cylindrical punch land is replaced with a circular profiled
punch land. Using a circular profiled punch land, a slight tilt of the
punch gives only rise to minor changes in the contact conditions between
punch land and can wall and thus only rise to minor variations in the
wall thickness. The backward extrusion of a high thin walled aluminium
can has been carried out experimentally and the results show that cans
produced with the circular profiled punch land have a significant lower
variation in wall thickness than the cans produced with the punch with
the cylindrical punch land.
|
|
Prediction of limits of lubrication in strip reduction testing
|
|
D.D. Olsson, J.L. Andreasen, N. Bay (1)
|
|
STC F, 53/1/2004, P.231
|
|
Keywords: Metal Forming, Tribology, Galling |
Abstract : Pick-up and galling due to lubricant film breakdown
is a severe limitation in cold forming of tribologically difficult
metals like stainless steel and aluminium. The present paper describes a
method of combined experimental and numerical analysis to quantify the
limits of lubrication in a dedicated simulative strip reduction test.
The limit of lubrication is quantified as the threshold drawing length
before galling occurs. A numerical model of the test is stablished
calculating tool/work piece interface temperatures and normal pressures.
Identifying a critical maximum value of the interface temperature the
results show good agreement between numerically predicted and
experimentally observed threshold drawing lengths at different test
conditions.
|
|
Flow Stress Model Accounting for the Strain Localization during Plastic Deformation of Metals
|
|
M. Pietrzyk (2), V. Pidvysotskyy , M. Packo
|
|
STC F, 53/1/2004, P.235
|
|
Keywords: Flow Stress, Micro-Shear, Identification |
Abstract : Problem of description of flow stress in deformation
processes, in which materials behaviour is affected by the strain
localization, is discussed in the paper. Experiments included three
groups of plastometric tests: i) uniaxial compression with the
transverse flow not constrained by the tool; ii) channel die
compression, in which the flow in one of the directions perpendicular to
the die motion is constrained by the die?s wall, iii) ring compression.
Inverse analysis was applied to determine flow stress independent of the
inhomogeneities of deformation and of the influence of friction.
Combining the flow stress data with the state of strain in the material
allowed suggestion of the flow stress model accounting for the strain
localization.
|
|
Cold Sizing of Cold- and Hot-Formed Gears
|
|
B.-A. Behrens / E. Doege (1)
|
|
STC F, 53/1/2004, P.239
|
|
Keywords: Forming, gear, cold sizing process |
Abstract : At present, the dimensions, tolerances or surface properties
of cold- or hot-formed geared parts frequently fail to meet the demanded
quality standards. By introducing a cold sizing operation, substantially
narrower tolerances can be achieved reducing the need for subsequent
machining processes. A major problem, not only concerning cold sizing
but also any other cold bulk metal forming operation is the elastic die
deflection caused by the high pressure loads on the die cavities during
the forming process. In this context, a closed-die cold sizing process
of a straight-toothed planetary gear has been investigated in terms of
the occurring elastic die deflection which is a threat to the
geometrical accuracy of the component. Two strategies have been employed
to minimize the elastic die deflection. The first strategy consists in a
correction of the die cavity?s tooth profile based on the finished
part?s deviation from its theoretical shape determined through
Finite-Element-Analysis (FEA). The key idea underlying the second
strategy is an innovative tooling concept which compensates the elastic
die deflection by means of a counter pressure generated by an elastomer
ring embedded in the lower die. Being of equal magnitude, the pressure
arising in the workpiece and the counter pressure generated in the
elastomer ring compensate each other at the inner die walls and, thus,
the elastic deflection of the lower die is inhibited. The developed
tooling system of active deflection compensation provides the cold
sizing of straight-toothed gearwheels with improved dimensional
accuracy. For the sizing process subject to this study the average
profile and helix deviations of the sized gears can be reduced
substantially with the help of the proposed tooling concept. The
advantages of the active deflection compensation have been confirmed in
numerical and experimental investigations.
|
|
Forming of micro channels with ultra thin metal foils
|
|
B.Y. Joo, S.I. Oh (1), Y.K. Son
|
|
STC F, 53/1/2004, P.243
|
|
Keywords: Micro, Sheet Forming, Wafer Die |
Abstract : The objective of this paper is to investigate the feasibility
of producing micro scale structures by forming ultra thin metal foils.
During this investigation, flat rolled foils of AISI 304 stainless steel
(2.5µm in thickness) and pure copper (3.0µm in thickness) were formed
into channels of varying shapes. The shapes of these channels were
straight lines, concentric circles, crosses, and other curved shapes.
The cross sections of the channels ranged from 10~20µm wide and 5~10µm
deep. Forming was done by cold isostatic pressing. Two types of micro
dies were used. One was made of SU-8 photo resist on a Si wafer, the
other of dry etched (DRIE) Si wafer. The die and metal foil were vacuum
packed in a bag made of multilayered film. The forming was conducted
with a 240MPa cold hydrostatic press. The formed parts were examined in
terms of their dimensions, surface qualities, and potential for defect.
The fabrication results show that the sheet metal forming process can be
applied to the manufacturing of micro scale structures.
|
STC G |
|
Polishing of Structured Molds
|
|
E. Brinksmeier (1), O. Riemer, A. Gessenharter, L. Autschbach
|
|
STC G, 53/1/2004, P.247
|
|
Keywords: Polishing, Ultra-Precision Machining, Mold Making |
Abstract : High precision molds for the replication of structured optical
elements like Fresnel lenses or prism arrays are generated by diamond
machining or precision grinding. In some cases surface quality of the
replicated components is not sufficient to meet the increasing demands
concerning surface roughness and form accuracy for optical applications.
Subsequent polishing of the structures may therefore be necessary.
Within this work structured molds were finished by a newly developed
abrasive polishing process, by laser polishing, and by abrasive flow
machining. This paper focuses on the material removal mechanisms and
achievable surface quality in abrasive polishing. Surface quality is
compared to that achieved by laser polishing and abrasive flow machining.
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Simulation and Improvement of the Micro Abrasive Blasting Process
|
|
B. Karpuschewski (2), A.M. Hoogstrate, M. Achtsnick
|
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STC G, 53/1/2004, P.251
|
|
Keywords: Micro machining, Abrasion, Blasting |
Abstract : Micro abrasive blasting (MAB) is becoming an important
machining technique for the fabrication of Micro Electro Mechanical
systems. The process is based on the erosion of a mask-protected brittle
substrate by an abrasive-laden air jet. Currently available blasting
machines are relatively simple. However, to exploit this technique for
applications of industrial interest a more efficient and controllable
process is required. In this paper abrasive blasting is analysed by
means of a set of models containing different sub-models for the
particle beam, the material removal mechanism and the resulting blasting
profile. A new line-shaped Laval nozzle has been developed, which is
able to increase the particle velocity by 40%37; compared to a conventional
round nozzle. The blasting-profile of this line-shaped nozzle is more
uniform and the material removal rate is significantly higher compared
to conventional nozzles, which in turn leads to higher achievable aspect
ratios of the three-dimensional microstructures.
|
|
Process Requirements for Cost-Effective Precision Grinding
|
|
W.B. Rowe (1), S. Ebbrell
|
|
STC G, 53/1/2004, P.255
|
|
Keywords: Grinding, Cubic boron nitride (CBN), High speed |
Abstract : Costs in precision cylindrical grinding are compared for
different abrasives, machines and grinding conditions. The analysis is
for repeated batch production. Account is taken of machine cost and
abrasive cost. Cost comparisons were based on extensive trials to assess
re-dress life against workpiece quality requirements. Experiments show
that different workpiece materials require different strategies to
reduce costs. Easy-to-grind AISI 52100 and difficult-to-grind Inconel
718 materials were ground at conventionaln speeds and at high speeds. It
is shown that wheels speed affects production rate through acceptable
values of re-dress life, removal rate and dwell time. Advantages were
gained using vitrified CBN wheels at conventional speed and at high
speed. For both materials, vitrified CBN wheels used at high speed, gave
better quality at lower cost than conventional abrasives. Wheel costs
became negligible and labour costs greatly reduced. Re-dress life
trials, usually neglected, are shown to be essential to reduce costs and
maintain quality [1].
|
|
Three Dimensional Finite Element Simulation of Transient Heat Transfer in High Efficiency Deep Grinding
|
|
T . Jin, D.J. Stephenson (2)
|
|
STC G, 53/1/2004, P.259
|
|
Keywords: Grinding, Finite element method, Temperature |
Abstract : 3D Finite Element simulations have been carried out to
investigate transient heat transfer under high efficiency deep grinding
(HEDG) conditions. The results have been compared to those obtained from
2D analytical models and experimental measurements. It has been found
that the steady-state heat transfer condition can be readily obtained in
HEDG after the maximum contact length is achieved and that side wall
convective cooling has little effect on the grinding temperatures for
thin steel plates. The temperature distribution on the workpiece across
the grinding width in cylindrical grinding shows obvious slopes and film
boiling of grinding fluid may occur at the trailing edge of grinding
width. Good agreement has been found between the FE results and
experimental observations. 3D FE simulation and 2D analytical modelling
predict quite similar values for the maximum temperatures on the
finished surface of the workpiece.
|
|
Model-Based Monitoring and Control of Continuous Dress Creep-Feed Form Grinding
|
|
C. Guo (3), M. Campomanes, D. McIntosh (3), C. Becze / S. Malkin (1)
|
|
STC G, 53/1/2004, P.263
|
|
Keywords: Form grinding, monitoring, turbine blades |
Abstract : This paper is concerned with process monitoring and control of
Continuous Dress Creep-Feed (CDCF) form grinding using model-based
simulation and in-process power measurement and its application to
grinding of turbine blade root serrations. For blade root serration
grinding, it is essential that the grinding force be maintained below a
critical limit to avoid cracking of the Thermal Environmental Barrier
Coating (TEBC) at the blade airfoils, and that the heat flux at the
grinding zone be kept below the fluid burnout limit to avoid thermal
damage to the part. A blade root form grinding process is first
simulated and optimized by utilizing the variable-feed approach
developed previously, whereby both the dress infeed and part feed rate
are adaptively varied to minimize cycle time while maintaining the force
and heat flux below specified limits. Both the grinding forces and heat
flux are obtained from the measured power. Maintaining the monitored
power signature from production processes within the acceptable power
limits established in this way ensures a ?normal? grinding process.
Deviations from the normal process signature profile indicate possible
process issues.
|
|
Fast Grinding Process Control with AE Modulated Power Signals
|
|
J.F.G. Oliveira (2), C.M.O. Valente
|
|
STC G, 53/1/2004, P.267
|
|
Keywords: Grinding monitoring, Acoustic emission, Deburring |
Abstract : Power and acoustic emission (AE) are among the most commonly
used signals for monitoring of grinding processes. The electric current
at the main motor has being used to measure the grinding power. However
its response is slow. The AE signal presents a fast response but its
level can be highly influenced by external factors. This paper proposes
a monitoring approach based on a new parameter called Fast Abrasive
Power (FAP). The FAP is the modulation of the electric power by the AE
signal dynamics. The FAP can be fast enough to detect sudden process
variations and reliable enough to represent the grinding power.
|
|
Optimization of Set-up Conditions for Stability of The Centerless Grinding Process
|
|
F. Hashimoto (2), G.D. Lahoti (1)
|
|
STC G, 53/1/2004, P.271
|
|
Keywords: Centerless grinding, Optimization, Process stability |
Abstract : The stability of the centerless grinding process is very
sensitive to the set-up conditions due to the uniqueness of the
work-holding system. Centerless grinding produces precision components
with high productivity only when the set-up condition is optimally
chosen. This paper describes the effect of set-up conditions on three
stability criteria of the centerless grinding system. It also presents
guidelines for determining proper set-up conditions to avoid spinners,
chatter vibration and roundness problems. Finally, an algorithm for
providing the optimum set-up condition based on process aims is proposed
and the simulation results are discussed.
|
|
Basics for In-Process Roundness Error Improvement by a Functional Workrest Blade
|
|
F. Klocke (1), D. Friedrich, B. Linke, Z. Nachmani
|
|
STC G, 53/1/2004, P.275
|
|
Keywords: Grinding, Centerless, Simulation |
Abstract : A centerless plunge feed grinding process can be conducted
?below center? in order to increase process productivity. This statement
results from the fact that the workpiece, in such a set up of the
grinding gap, is fixed between grinding wheel, control wheel and
workpiece rest blade, thus allowing higher feed rates of the grinding
wheel support. But when grinding ?below center?, the advantage of a
higher productivity is accompanied by a negative effect, the arise of a
polygonal workpiece form. Regarding only the geometrical rounding effect
as one reason for this process characteristic phenomenon, different
workpiece center displacements are examined and analytically described.
The knowledge of relevant workpiece center move-ments within a
centerless grinding application allows a quantified analysis of the
influence of these displacements on the geometrical rounding effect.
Deriving from such an analysis, a functional workrest blade is
discussed, which influences the stability of the geometrical rounding
effect.
|
STC M |
|
Method for the Optimization of Forming Presses for the Manufacturing of Micro Parts
|
|
P. Groche (2), R. Schneider / D. Schmoeckel (1)
|
|
STC M, 53/1/2004, P.281
|
|
Keywords: Press, Dynamic, Simulation |
Abstract : In order to enable the efficient and economical production of
micro parts with high demands on tolerances and accuracy, it is
necessary to establish efficient, productive and dynamically optimized
forming presses. This paper introduces a new simulation strategy for the
optimization of high precision presses. A newly developed and existing
prototype of a linear motor press was used to experimentally verify the
simulation results. The experimental investigations, which especially
focus on horizontal slide displacements under dynamic loads, showed a
good correspondence with the results from the simulations. The presented
innovative simulation strategy offers improved possibilities of
evaluating and optimizing the dynamic press behavior in the early design
process with a reduced effort of experimental optimization.
|
|
Hybrid Model of High Speed Machining Centre Headstock
|
|
J. Jedrzejewski (1), Z. Kowal, W. Kwasny, W. Modrzycki
|
|
STC M, 53/1/2004, P.285
|
|
Keywords: machine tool, modelling, spindle |
Abstract : A hybrid high-speed machining centre headstock model based on
two computation methods: the finite element method and the finite
difference method is presented. The model allows one to calculate
precisely the headstock?s indices on the basis of which its optimal
operating characteristics can be determined. The presented modelling
methods allow one to evaluate a design from thermal, stiffness and
durability points of view. By way of illustration, the behaviour of
three machining centre headstocks with: an electrospindle on rolling
bearings, a conventional spindle and an electrospindle on aerostatic
bearings are modelled using the hybrid model.
|
|
Finite Element Modelling of Ball Screw Feed Drive Systems
|
|
M.F. Zaeh, T. Oertli / J. Milberg (1)
|
|
STC M, 53/1/2004, P.289
|
|
Keywords: Finite element method (FEM), Mechatronic System, Machine Tool |
Abstract : For full realization of the feasible drive performance on
machine tools, the dynamic behaviour of the entire mechatronic system
must be analysed and optimized integrally during design of the machine.
To permit complete modelling of the machine tool frame structure with
integral ball screw feed drive systems by means of the finite element
method (FEM) a specific model approach for ball screw drives is
presented, which is a prerequisite for the FEM modelling of a complete
machine tool based on feed drives of this type. The feed axis of a feed
drives test station serves here as an example for demonstration of the
modelling of feed drives. The FEM model is integrated into a mechatronic
model of the axis control system and the be-haviour of the position and
speed control loop is simulated.
|
|
"Hardware in the Loop" Simulation of Machine Tools
|
|
G. Pritschow(1), S. Röck
|
|
STC M, 53/1/2004, P.295
|
|
Keywords: Simulation, Computer numerical control (CNC), Hardware in the Loop |
Abstract : This paper describes a time-deterministic model for the
real-time simulation of machine tools using a real CNC. The realized
virtual machine tool was validated by comparing the simulated milled
work piece with a machined one. The results demonstrate that despite the
real-time demands an accurate representation of the machine tool?s
behavior can be achieved.
|
|
Compensation of Thermo-elastic Machine Tool Deformation Based on Control internal Data
|
|
C. Brecher, p. Hirsch / M. Weck (1)
|
|
STC M, 53/1/2004, P.299
|
|
Keywords: Thermal, Compensation, Accuracy |
Abstract : The thermo-elastic behaviour of machine tool structures leads
to unwanted displacements at the tool centre point (TCP) and has a
significant influence on the machining accuracy. In the past, therefore,
numerous direct and indirect compensation methods were developed to
reduce and/or compensate the thermo-elastic displacements. The paper
describes a new indirect compensation approach which allows the
abandonment of all additional sensors with the exception of one
environmental temperature sensor. As input control internal data of the
feed drives and the main spindle are used exclusively. The rotational
speed and motor current values - the latter correlate to the drive
torque - represent the thermal load parameters of the machine. A
combination of first and second order time delay elements describes the
displacement behaviour of the machine resulting from these load
parameters. The parameters of the time delay elements are determined by
a systematic calibration procedure. The resulting displacements are
calculated online and superposed as offset-values for the correction of
the respective axis positions. Practical experiments show that with this
elementary method a reduction of the thermo-elastic displacements of
more than 80 %37; of the initial value is possible.
|
|
Dynamic Compensation of Spindle Integrated Force Sensors
|
|
Y. ALtintas (1), S. Park
|
|
STC M, 53/1/2004, P.305
|
|
Keywords: Milling, Force, Sensor. |
Abstract : This paper presents a dynamically compensated
Spindle-Integrated Force Sensor system to measure cutting forces.
Piezo-electric force sensors are integrated into the stationary spindle
housing to measure cutting forces in three directions. The transfer
function of the spindle structure between the cutting forces acting on
the tool tip and the measured forces at the spindle housing are
identified. Using the cutting force signals measured at the spindle
housing, a Kalman filter is designed to filter the influence of
structural modes on the force measurements. The frequency bandwidth of
the force measurement system is significantly increased with the
proposed sensor and the signal processing method. Milling experiments
with tooth passing frequencies up to 1000 Hz are presented with
effective removal of cutting force distortions caused by three
structural modes of the spindle.
|
|
Creating Stability Lobe Diagrams during Milling
|
|
E. Abele (2), U. Fiedler
|
|
STC M, 53/1/2004, P.309
|
|
Keywords: chatter; milling; spindle |
Abstract : Motorized spindles are in common use in high-speed high-power
machining. The majority of the motorized spindle shafts are supported by
angular contact ball bearings. The bearings kinematics and its stiffness
depend on the spindle speed and the temperature of the spindle shaft.
The stiffness usually decreases with the number of revolutions and
increases with temperature. The static and dynamic stiffness of the
spindle, which is determined by the bearings and the shaft stiffness,
also depends on the temperature and the actual number of revolutions.
The dynamic behavior of the spindle during milling, particularly, the
behavior concerning chatter, is crucially affected by the dynamic
behavior of the mechanical system. If the frequency response function is
measured at speed zero of the spindle, the stability lobe diagrams are
incorrect, because the influence of speed and temperature are not
considered. The correct forecast of the critical depth of cut and in
particular the favourable speed ranges, were the largest depths of cut
are possible, is strongly disturbed. During HSC-machining this effect
can not be neglected. This paper presents the reasons for the
speed-sensitive stiffness and discusses the influence on the dynamic
behavior of spindle systems. The dynamic behavior of a spindle-tool
system is measured as a function of spindle speed and the consequences
for process stability are shown. Furthermore, a new method of measuring
the dynamic behavior during milling with the help of
sub-space-state-space-identification methods is introduced. Finally, the
computed stability lobe diagrams are compared with experimentally
determined stability maps.
|
|
A Cutting Force Estimator for CNC Machining Centers
|
|
M. Dölen, B. Kaftanoglu (1), R.D. Lorenz
|
|
STC M, 54/1/2004, P.313
|
|
Keywords: Machine, Estimating, Measurement |
Abstract : This study presents a cutting force estimator topology for
feed drives of CNC vertical machining centers to compute the machining
forces accurately. The estimator employs recursive discrete Fourier
transform to not only estimate inertial forces on the system but also to
filter effectively the noise components in the measurements. The
accuracy of the estimator is compared to that of a Luenberger observer
while the overall performance of the estimator is evaluated through an
experimental study. The paper also discusses its inherent limitations.
|
|
High-performance NC for high-speed machining by means of polynomial trajectories
|
|
C. Lartigue, C. Tournier, M. Ritou, D. Dumur (1)
|
|
STC M, 53/1/2004, P.317
|
|
Keywords: machining, NC, polynomial format |
Abstract : High-Speed Machining (HSM) is now widely used to machine
sculptured surfaces as it ensures a high level of geometrical surface
quality in a competitive machining time. However, the performance of HSM
is strongly linked to the combination CAM system/Numerical Controller.
The CAM system produces a tool trajectory and the related feed-rates,
information which is afterward transmitted to the NC. The role of the NC
is thus to control the machine tool axes providing feed-rates as close
as possible to the programmed ones, while respecting a maximum contour
lag error. This paper presents an analysis of the performance of the
combined CAM system/Numerical Controller within the context of HSM. In
particular, attention is focused on tool paths designed by the CAM
system in terms of polynomial curves or polynomial surfaces. Concerning
the latter, tool trajectories are described in the parametric space of
the surface. Such calculated trajectories thus eliminate positioning and
chord errors. Furthermore, it is shown that, besides the geometrical
interest of native polynomial formats of tool paths, these descriptions
lead to a high-performance NC behavior: efficient axis control,
limitation of the slow-downs, increase of the mean feed-rate.
|
|
Gain-scheduling control of machine tools with varying structural flexibilities
|
|
W. Symens, H. Van Brussel (1), J. Swevers
|
|
STC M, 53/1/2004, P.321
|
|
Keywords: Control, Flexibility, Gain-scheduling |
Abstract : The high accelerations occurring in present-day machine tools
are likely to excite the vibration modes of the machine structure. In
order to achieve a high control bandwidth and high contouring accuracy,
these structural eigenfrequencies need to be incorporated in the
controller design. They are however not constant but depend on the
position of the tool in the machine?s workspace. To control such linear
time-varying (LTV) systems, two approaches are possible: (i) robust
control, and (ii) adaptive control, e.g. by gain-scheduling. In this
paper, the gain scheduling control approach is discussed and verified on
an experimental set-up, consisting of one axis of an industrial
pick-and-place machine, driven by a linear motor, and containing a
flexible beam of variable length. H-infinity controllers are designed
for several constant arm lengths and scheduled ad-hoc in function of the
beam length. Further, analytically scheduled controllers are designed
using a global LTV model of the set-up. As inherent conservatism of the
analytical approaches limits the performance of these analytically
scheduled controllers, a hybrid design methodology is proposed.
|
|
Development of Gel Structured Electrorheological Fluids and their Application for the Precision Clamping Mechanism of Aerostatic Sliders
|
|
T. Aoyama (2)
|
|
STC M, 53/1/2004, P.325
|
|
Keywords: Development, Functional, Fluid |
Abstract : Electrorheological fluids (ERF) are functional fluids whose
viscoelastic property varies according to the intensity of the applied
electric field. The disadvantages of ERF are the sedimentation of ER
particles and the requirement of a seal mechanism. In order to solve
these problems, gel structured electrorheological fluids (ERG) are
developed in this study. The basic characteristics of the ERG film are
experimentally analyzed. The ERG is applied to the clamping mechanism of
aerostatic slider. By using the ERG element, the aerostatic slider can
be clamped with extremely low clamping force. The ERG clamp also serves
as a variable damping element of aerostatic slider.
|
|
Performance of Pseudo-Elastic Flexure Hinges in Parallel Robots for Micro-Assembly Tasks
|
|
J. Hesselbach, A. Raatz / H. Kunzmann (1)
|
|
STC M, 53/1/2004, P.329
|
|
Keywords: Robotics, Kinematics, Compliant Mechanism |
Abstract : This paper presents the application of pseudo-elastic flexure
hinges in parallel robots for micro-assembly tasks. The material used
for the flexure hinges is a shape memory alloy permitting angular
deflections of ± 30°. Based on this flexibility sufficiently large
workspaces of the robots can be achieved. Simulations show that
kinematic deviations caused by flexure hinges are reducing the absolute
positioning accuracy of compliant mechanisms. Likewise the simulations
indicate that the kinematic behaviour of compliant mechanisms differs
only slightly from their counterparts with conventional joints, which
are analytically described by means of a rigid-body model. Experimental
measurements with two compliant robots show the possibility to increase
repeatability and resolution by using flexure hinges. These measurements
yield to a repeatability of RP=1µm (at 3Sigma)with the planar robot and
a repeatability of RP=0.3µm and a variance of multiple direction
position accuracy vAP=0.15µm with the spatial robot. Due to the
compliance the settling time to reach a stable position is higher than
with conventional robots but for the spatial robot vibrations could be
minimised because of an optimised design of the structure and the
combined flexure hinges.
|
|
Machine Tool with Active Magnetic Guides
|
|
B. Denkena (2), F. Kallage, M. Ruskowski, K. Popp / H.K. Tönshoff (1)
|
|
STC M, 53/1/2004, P.333
|
|
Keywords: Machine, Bearing, Magnetic |
Abstract : High speed and high dynamic machining strategies require
specific solutions for the components. The limits for speed and accuracy
mainly depend on the machine structure, the drives and the guides. In
this paper the development of a new high speed machining centre with
actively controlled linear magnetic guides will be presented. The
stiffness and damping properties of this innovative component will be
discussed. The machining centre is equipped with linear direct drives in
all three axes and uses lightweight slides on a solid concrete base. The
machine structure and first results will be presented and compared to
conventional machine tools.
|
|
X-Y-? Nano-Positioning Table System for a Mother Machine
|
|
H. Shinno (2), H. Hashizume, H. Yoshioka, K. Komatsu, T. Shinshi, K. Sato
|
|
STC M, 53/1/2004, P.337
|
|
Keywords: Nano-positioning, Ultra-precision machine tool, Table system |
Abstract : Within recent manufacturing environment, there is an
increasing demand for nanometer positioning table system with high
stiffness, high resolution and high repeatability. In this study,
therefore, a high-stiffness X-Y-? nano-positioning table system has been
developed for ultraprecision machine tools. The table is levitated by
high-stiffness aerostatic bearings with porous material and driven by
six voice coil motors in a non-contact condition. The table system is
designed symmetrically about the driving axis and consequently free from
nonlinear behavior and direction dependency. The performance of the
developed table system has been verified through a series of
nano-positioning experiments.
|
|
Development of a Elliptical Vibration Milling Machine
|
|
T. Moriwaki (1), E. Shamoto, Y.C. Song, S. Kohda
|
|
STC M, 53/1/2004, P.341
|
|
Keywords: Milling machine, Hardened steel, Vibration cutting |
Abstract : A unique elliptical vibration milling machine is developed by
utilizing a double-spindle mechanism. The developed machine generates
circular vibratory motion of the cutting tool mechanically by rotating
an eccentric sleeve with a built-in motor. The radius and the maximum
frequency of the circular vibration are set to 0.5mm and 167Hz
respectively. The developed machine is applied to elliptical vibration
planing by clamping the tool spindle, and also to elliptical vibration
end milling by rotating the inner tool spindle as well at the same time.
The machining tests of hardened steel with CBN and coated carbide tools
are carried out, and it was proved that the elliptical vibration cutting
shows better results as compared with conventional cutting without
elliptical vibration motion. A mirror surface on hardened steel with a
roughness of about 0.11 µm Ra was obtained by elliptical vibration
planing by employing a single crystal diamond tool.
|
|
New Light and Higly-Damped Bonded Structures for Noise and Vibration Reduction
|
|
M. Zatarain (3), C. Villasante, A. Sedano / R. Bueno (1)
|
|
STC M, 53/1/2004, P.345
|
|
Keywords: Damping, Bonding, Accuracy |
Abstract : The current trend with machine tool structures is the
reduction of weight of their moving parts. The present paper looks at a
method for achieving this, namely that of bonding rigid materials,
whether or not of metal. Special emphasis is laid on achieving
structures with a high damping ratio. The method makes it possible to
combine materials and thicknesses, and produce closed, ribbed sections.
To assess the behaviour of these structures it was necessary to develop
a tool that adds to the features of a finite-element system. With this
tool it is possible to assess not only rigidity and mass, but also
damping. Various glues were tested, so that those providing optimum
rigidity and damping may be used. The prototypes demonstrate the
validity of the technology of bonding and of the method of verification.
|
STC O |
|
Adaptation and Learning in Distributed Production Control
|
|
L. Monostori (1), B.Cs. Csáji, B. Kádár
|
|
STC O, 53/1/2004, P.349
|
|
Keywords: Distributed production control, Agent based manufacturing system, Machine learning |
Abstract : Distributed (agent-based) control architectures offer
prospects of reduced complexity, high flexibility and a high robustness
against disturbances in manufacturing. However, it has also turned out
that distributed control architectures, usually banning all forms of
hierarchy, cannot guarantee optimum performance and the system behaviour
can be unpredictable. In the paper machine learning approaches such as
neurodynamic programming and simulated annealing are described for
managing changes and disturbances in manufacturing systems, and to
decrease the computational costs of the scheduling process. The results
demonstrate the applicability of the proposed solutions, which can
contribute to significant improvements in system performance, keeping
the known benefits of distributed control.
|
|
Adaptive Control of Supply Chains: Building blocks and tools of an agent-based simulation framework
|
|
B. Scholz-Reiter (2), H. Höhns, T. Hamann
|
|
STC O, 53/1/2004, P.353
|
|
Keywords: Adaptive control, Agent, Coordination |
Abstract : An adaptive control concept for supply chains is presented.
Its background is a complex supply chain scenario originating from the
machine building domain with a focus primarily on the development of an
agent-based method concerning the adaptive coordination of customer
orders along the supply chain. It aims at flexibly handling disturbances
in relation to the re-allocation of alternative suppliers to ensure a
timely and accurate fulfillment of customer orders. The researched and
described building blocks and tools originate from artificial
intelligence, decision theory and operations management, which have been
implemented in an agent-based simulation framework.
|
|
Backlog Control Design for a Closed Loop PPC System
|
|
J-H. Kim, N.A. Duffie (1)
|
|
STC O, 53/1/2004, P.357
|
|
Keywords: Production, Control, Analysis |
Abstract : In this paper a discrete dynamic model of a single workstation
is used to design and analyse control algorithms for closed-loop PPC
that improve performance, especially response to disturbances such as
rush orders and periodic fluctuations in capacity, while ensuring that
dynamic behavior remains favorable and robust. The presence of delays in
adjusting capacity presents challenges in both dynamic analysis and
control algorithm design that are addressed in the paper. Methods of
control engineering, such as transfer function and frequency response
analysis, are used to make analysis of fundamental system properties
tractable and to improve control of dynamic behavior.
|
|
Operation of Manufacturing Systems with Work-in-process Inventory and Production Control
|
|
Y-H. Ma, Y. Koren (1)
|
|
STC O, 53/1/2004, P.361
|
|
Keywords: Manufacturing, Control, Optimization |
Abstract : The operation of large manufacturing systems with buffers has
two goals: to meet production target and minimize the work-in-process
(WIP) inventory. This paper introduces a novel approach, based on
optimal control theory, to achieve both goals simultaneously by on-line
adjustment of the production rate of each machine. In this method the
state variables are the buffer levels, the control variables are the
machine production rates, and the output variable is the target
production (the demand). The method is evaluated through simulations
under various conditions, and compared with other methods in the
literature. The results demonstrate that the proposed method can
successfully produce low WIP inventory than other methods, while the
required production demand is still fulfilled. It is also shown that the
method is capable of providing feasible solutions for large
manufacturing systems ? a goal that is harder to achieve with the
current known method.
|
|
A Deadlock Handling Method for Automated Manufacturing Systems
|
|
J. Zajac / M. Szafarczyk (1)
|
|
STC O, 53/1/2004, P.367
|
|
Keywords: Manufacturing System, Control, Deadlock |
Abstract : Deadlock-free operation is a principal requirement for an
automated manufacturing system. The part types passing through the
manufacturing system are characterized by the sequence of the
manufacturing resources required for their completion. The method
partitions the sequence into alternate subsequences consisting of
deadlock-free resources and deadlock-risk resources. The set of
deadlock-free resources is shown. The proposed method introduces a novel
structural on-line control policy which guarantees that the execution of
an operation representing an elementary step of a job relating to a part
does not lead to deadlock. The proposed policy is suitable for
implementation in modern distributed manufacturing control systems due
to the low on-line computational costs.
|
|
3-Sigma PPC ? A Holistic Approach for Managing the Logistic Performance of Production Systems
|
|
P. Nyhuis / H-P. Wiendahl (1)
|
|
STC O, 53/1/2004, P.371
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Keywords: Optimisation, Production, Management |
Abstract : Recent developments have led to substantial improvements of
production planning and control systems. Despite this, manufacturing
companies still have difficulties in meeting their logistic performance
objectives and the logistic performance requirements of customers. In
order to solve this problem, the 3-Sigma PPC approach introduced in this
paper proposes two important innovations. Firstly, 3-Sigma PPC takes a
holistic view of PPC systems. It considers the effects that the logistic
models, the organisational structure and the decisions of actors of a
PPC system have on its logistic performance. Secondly, 3-Sigma PPC
comprehensively transfers quality management principles to the context
of production management.
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Aggregation ? the Key to Integrating Production Planning and Scheduling
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J. Váncza (2), T. Kis, A. Kovács
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STC O, 53/1/2004, P.377
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Keywords: Production, Planning, Scheduling |
Abstract : In this paper we suggest an integrated planning and scheduling
framework with a special emphasis on the link between these control
levels. Our planning model is generated automatically by performing
aggregation on de facto standard product and technology related data in
the dimensions of time, resource capacities and operations. The method
addresses make-to-order production environments. An industrial case
study is also presented, demonstrating how our algorithms work on
large-scale problem instances.
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Chaos Theory in Production Scheduling
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G. Chryssolouris (1), N. Giannelos, N. Papakostas, D. Mourtzis
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STC O, 53/1/2004, P.381
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|
Keywords: Scheduling, Control, Decision-making |
Abstract : In this paper the concept of chaos in manufacturing systems is
briefly introduced and tools used in the characterization of a chaotic
system are discussed. The scheduling of a simple manufacturing system,
with the help of commonly used assignment rules, has been simulated
first. The results have been studied with the help of phase portraits.
Some conclusions have been drawn and a new method for scheduling is
proposed. The method is tested against conventional rules and the
results are evaluated and discussed.
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Emergent synthesis approaches to control and planning in make to order manufacturing environments
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K. Ueda (1), A. Lengyel, I. Hatono
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STC O, 53/1/2004, P.385
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Keywords: Manufacturing Systems, Optimization, Emergent Synthesis |
Abstract : The main goal of manufacturing systems with make to order
environments is to provide for unique requirements of consumers. The
demand for products can vary not only in product variety but in optimum
criteria. However a manufacturing system might be capable of producing
the required product, there can emerge difficulties for the system to
fulfill the cost and time related constraints of the consumer. This
paper introduces emergent synthesis approaches to manufacturing control
and production planning in make to order environments to evaluate and
control the range of time and cost constraints that the system is able
to complete. Three factors of constraints are taken into account in the
proposed model: the constraints of the consumer's specification as the
expected price and due date of a product, the environmental constraints
as the range of possible due dates and costs of a product, and the
constraints of the system purpose as the long term operation policy. To
evaluate the overlapped space of these constraints emergent synthesis
approaches are implemented. Emergent synthesis classifies problems into
three types whether completeness in the description of the environment
and specification can be achieved or not. Since in make to order
environments the specifications of consumers can be different and the
environmental conditions depend on undetermined demands for products the
model belongs to the Class III type problems, where the description of
the specification and the environment is incomplete. In the approach to
the problem it is assumed that the specification can be determined at
any time through the interaction between the system and the consumer,
thus the problem becomes a Class II type, where the description of the
environment is incomplete, but the description of the specification is
complete. The task of the model in this case is to adapt the dynamic
environment and determine the environmental constraints. When the
constraints of the environment and the specification are evaluated then
the model faces a Class I type problem with complete description.
However the problem is completely described, it can occur that no
satisfying solution is found by the determined constraints. In this case
the problem becomes again a Class III type and new interactions are
needed in order to harmonize the specifications with the environmental
constraints. The proposed model consists of the management (Class III),
the job shop control (Class II) and the production planning (Class I).
The simulation results show that the management is able to form
long-term operation policy of the system that can be tuned to follow the
demand of the market. The job shop control can accurately estimate the
lead-time of jobs in dynamic environments and schedule jobs to be
completed at the estimated time. The production planning is capable of
creating production plans of jobs that meet the requirements of
consumers for price and due date.
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A new method to cope with decision makers' uncertainty in the equipment selection process
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G. Manassero, Q. Semeraro, T. Tolio (2)
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STC O, 53/1/2004, P.389
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|
Keywords: Decision making, Flexible manufacturing system (FMS), Analytic hierarchy process (AHP) |
Abstract : One of the main problems faced while configuring or
reconfiguring manufacturing systems is to rank alternative designs
taking into account all the different aspects involved (both tangible
and intangible). For this purpose the Analytic Hierarchy Process (AHP)
is a well-known decision making support method that addresses this
problem. A major drawback of AHP is that uncertainty in the judgments of
the decision makers and the resulting impact on the ranking is not
considered. In real situations, however, judgments based on perceived
future scenarios are almost always uncertain. To solve this problem in
this paper we present the first complete probabilistic extension to the
AHP method. The new method provides the decision maker not only with
information on the ranking of the alternatives but also the probability
that the ranking remains stable even in presence of uncertainty in the
judgements. We verified the validity of the new method in a real
application developed for the Ferrari racing team.
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Life Cycle-Based Service Design for Innovative Business Models
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H. Meier / W. Massberg (1)
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STC O, 53/1/2004, P.393
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|
Keywords: Life Cycle Management, Maintenance, Service Engineering |
Abstract : A successful service business requires a new life cycle-based
approach with a comprehensive view of the real customer?s demands. This
includes the establishment of innovative business models. These business
models cover the fields of planning, finance, ramp up, revamping, take
back as well as a guarantee for the availability to supply maintenance
and repair. The latter can finally lead to the operation of the machine
itself in a performance-contracting model. Business models will also
offer an excellent way to develop ecological potentials while fulfilling
economic constraints. This was the background for a research project to
analyze the machine-oriented service development with the goal of
standardization, rationalization, and automation of life cycle-oriented
service processes. Therefore, a service configurator was developed for
the efficient supply of customer-based services. The configurator will
also consider the suppliers of the machine manufacturer. The results
were evaluated in an industrial environment with the help of an
innovative business model.
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Proposal of Service CAD System - A Tool for Service Engineering
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T. Arai (1), Y. Shimomura
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STC O, 53/1/2004, P.397
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|
Keywords: CAD, Simulation, Service |
Abstract : To solve current industrial problems, manufacturers need to
supply service rather than materialized products to consumers. We
propose a novel engineering paradigm to deal with services, service
engineering. We define services as a state change. A service model
consists of three sub-models: scope model, view model and flow model. A
computer-aided design tool, called Service Explorer, is developed to
represent a network of the parameters and determines the influence
weight one another. As the result, we verify the usefulness of the
design tool.
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Assessment of Manufacturing Operational Complexity
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|
W.H. ElMaraghy (2), R.J. Urbanic
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STC O, 53/1/2004, P.401
|
|
Keywords: Man-Machine Systems, Manufacturing, Human-Factors |
Abstract : The manufacturing system must balance human characteristics,
needs, skills and capabilities within the technical and business
environment, in order to be effective and successful. A Systems Analysis
and Design approach was utilized to integrate manufacturing technologies
with the capabilities of human workers, in order to augment the
performance of both. A framework was created on which to build systems
analysis tools that focus on realistic factors within the manufacturing
environment, such as information quantity, diversity and content;
complexity (product, process and operational); task effort, and so
forth. A matrix methodology and an objective measure of complexity have
been developed that assess the three levels of manufacturing complexity:
product complexity, process complexity and operational complexity. The
focus of this paper is the ?operational complexity? and it provides
insight into the system performance and sensitivities when considering
human characteristics.
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The impact of run-up in ensuring Rapid Changeover
|
|
A.R. Mileham, S.J. Culley, G.W. Owen, L.B. Newnes, M.D. Giess, A.N. Bramley (1)
|
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STC O, 53/1/2004, P.407
|
|
Keywords: Flexibility, Manufacture, Rapid changeover |
Abstract : Rapid changeover is a key prerequisite for responsive
manufacture. A changeover is typically composed of three phases,
run-down, set-up and run-up. Other research has focused almost
exclusively on set-up with little being done to address the run-up
phase, although it has been shown that doing a set-up fast can often
result in a disproportionate increase in run-up. This paper investigates
run-up within processing lines for which a rich database of changeover
information was collected from several companies. Data mining techniques
were then used to identify the factors that had a direct influence on
the extent of run-up for a particular line.
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Integrated Inspection and Machining for Maximum Conformance to Design Tolerances
|
|
H.A. ElMaraghy (1), A. Barari , G.K. Knopf
|
|
STC O, 53/1/2004, P.411
|
|
Keywords: Optimization, Error Compensation, Design Tolerance |
Abstract : Designers? intent for the form, fit and function of products
is expressed by design tolerances the conformance to which is the main
objective of manufacturing processes. A methodology for maximizing the
adherence to the specified tolerances using an integrated machining and
inspection system is presented. Considering the desired tolerance
envelope of the part, an error decomposition technique is developed to
model machining errors caused by the systematic and non-systematic
errors in the machine tool. The model is used to adaptively plan the
final machining cuts, based on inspection feedback, to enhance the
geometric accuracy of the final product and is illustrated by an
example. This approach reduces scrap and rework and their associated costs.
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STC P |
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A Confocal Probe based on Time Difference Measurement
|
|
G.X. Zhang (1), Y.M. Fan, X. Gao, S.G. Liu, Z.R. Qiu, C.Z. Jiang, X.F. Li, J.B. Guo
|
|
STC P, 53/1/2004, P.417
|
|
Keywords: Measurement, Optical probe, Confocal |
Abstract : A low cost confocal probe based on time difference measurement
has been developed. A tuning fork is used to modulate the focal length
of the probe. An auxiliary arm is introduced to the optical system. This
arm can be utilized for carrying out lateral measurement or for
providing a reference signal. The position of the surface is determined
by measuring the time difference between two successive peak intensities
of the measuring signal or that between peak intensities of measuring
and reference signals. Some key problems in probe design are discussed.
A correlation based technique for determining the time difference
between two peak pulses is developed. Error compensation technique for
nonlinearity and other errors is introduced. The excellent performance
of the probe has been proven by experiments.
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|
Vibrational Probing Technique for the Nano-CMM based on Optical Radiation Pressure Control
|
|
Y. Takaya, K. Imai, T. Ha, T. Miyoshi / N. Kinoshita (1)
|
|
STC P, 53/1/2004, P.421
|
|
Keywords: Nano-CMM, Micro-probe, Optical measurement |
Abstract : Complex microcomponents are being realized with the recent
advancement of micromachining technologies such as micro-cutting, laser
process and micro-EDM. This technical trend in microfabrication requires
to establish the nano-CMM as a three dimensional coordinate measuring
machine which has the target accuracy of less than 50 nm within 10 mm
cubed working volume. This paper deals with dynamical and positional
sensing characteristics of the newly developed vibrational probing
technique for the nano-CMM. An optically trapped silica particle with
high sphersity is used as a miniaturized probing sphere with the
diameter of less than 10 micrometer. It is forced to vibrate with
several tens nanometer amplitude and more than 1 KHz frequency. It is
experimentally suggested that our method can achieve nanometer order
accuracy by measuring the vibrational amplitude while the probe is
approaching to the micro-step specimen with the mean height of 1.243
micrometer.
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A Precision Angle Sensor Using a Multi-cell Photodiode Array
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|
W. Gao, T. Ohnuma, H. Satoh, H. Shimizu, S. Kiyono / H. Makino (1)
|
|
STC P, 53/1/2004, P.425
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|
Keywords: Metrology, Sensor, Angle |
Abstract : This paper describes a compact and precision angle sensor
based on laser autocollimation. Instead of using a conventional bi-cell
photodiode (PD) as the detector, a new PD array with 16 cells is
specifically designed and fabricated with lithography facilities
available at the university. The width of each cell is designed to be 40
µm, which is slightly smaller than the light spot size on the focal
plane of the objective lens. Experimental results have shown that the
sensor has a resolution of 0.01 arc-seconds and a measurement range of
2300 arc-seconds, which is approximately 15 times larger than the range
of the same sensor with a bi-cell PD.
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R-Test, a new device for accuracy measurements on five axis machine tools
|
|
S. Weikert / W. Knapp (1)
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|
STC P, 53/1/2004, P.429
|
|
Keywords: machine tool, measuring instrument, calibration |
Abstract : When rotary axes (rotary tables and/or swivelling axes) are
used in combination with linear axes, the origin and the orientation of
the rotary axes have to be known accurately, because these parameters
strongly influence the accuracy of the machined work piece. The new
device measures X, Y, Z deviations of spherical movements of the tool
centre point simultaneously on continuous paths. These deviations,
measured at selected points are used to calibrate parameter errors like
squareness, parallelism, strut length, etc. The uncertainty budget of
the measurements is presented. Effects of thermal influences are shown.
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New advances in traceability of CMMs for almost the entire range of industrial dimensional metrology needs
|
|
E. Trapet, E. Savio, L. De Chiffre (1)
|
|
STC P, 53/1/2004, P.433
|
|
Keywords: Coordinate measuring machine (CMM), Uncertainty, Calibration |
Abstract : The paper reports on results of the European project EASYTRAC.
The first main goal of this project was to significantly reduce the
efforts associated with the traceability of industrial dimensional
metrology laboratories by means of the almost exclusive use of
coordinate measuring machines (CMMs) in combination with laser
interferometers. The second main goal was to develop and validate
CMM-specific methods for task-related measurement uncertainty analysis.
In this paper, significant achievements from the EASYTRAC project are
reported, with particular emphasis on : i) error compensation using
reversal techniques; ii) use of laser interferometers on CMMs to reduce
measuring uncertainty when calibrating standards of length; iii)
development of other task-specific calibration techniques; and iv) use
of multiple measurements strategies for uncertainty assessment.
Uncertainty analyses of virtually any measurable feature were performed
and validated, including freeform, gear and thread parameters. This work
has provided an extensive experimental basis for the elaboration of the
ISO/TS 15530 series of standards.
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Reference Algorithms for Chebyshev and One-Sided Data Fitting for Coordinate Metrology
|
|
C.M. Shakarji / A. Clement (1)
|
|
STC P, 53/1/2004, P.439
|
|
Keywords: Algorithm, Coordinate measuring machine (CMM), Optimisation |
Abstract : This paper describes reference algorithms developed at the
National Institute of Standards and Technology that fit geometric shapes
to data sets according to Chebyshev, maximum-inscribed, and
minimum-circumscribed criteria. Using an improved approach, we have
developed more reliable reference algorithms for Chebyshev fitting for
lines, planes, circles, spheres, cylinders, and cones. In the cases of
circles, spheres, and cylinders, we also include maximum-inscribed and
minimum-circumscribed fitting. In every case, we obtain the fit through
an iteration that begins by using a (relatively easy) least-squares fit
and then refine to the desired Chebyshev, maximum-inscribed, or
minimum-circumscribed fit. We discuss why computing these fits is
substantially more difficult than computing a least-squares fit, as the
topography of the objective function prevents certain naïve algorithms
from working. We describe our choice of simulated annealing as a method
that is general enough to be used for all the geometric shapes
considered, requiring minimal customization for each shape. We outline
steps taken for each geometric shape to reduce the number of fit
parameters, thus improving the performance of the algorithms. We
describe a suitable temperature reduction schedule that allows these
algorithms to converge. We note cases of nonuniqueness related to
maximum-inscribed fits. Finally we document test results showing the
effectiveness of these algorithms against a battery of data sets with
known solutions, against a limited number of exhaustive search results,
against intercomparisons with other algorithms that provide for some of
these fits, and against themselves by means of a repeatability study. We
note that during intercomparisons, we found significant differences
between our well-researched reference results and results obtained from
algorithms that can be found in industrial use today.
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|
Substitute Geometry of Multidimensional Features
|
|
V. Portman (1), V. Shuster, Y. Rubenchik, Y. Shneor
|
|
STC P, 53/1/2004, P.443
|
|
Keywords: Dimensional metrology, Geometric accuracy, Multidimensional feature |
Abstract : A substitute feature equation (SFE) which is of vital
importance in geometric accuracy problems depends on size, position, and
orientation deviations (SPODs). To synthesize the equation and evaluate
its numerical parameters using CMM measurements, it is necessary to
eliminate redundant components from the initial set of SPODs. For this
purpose, a linear space of the SPODs transfer functions is considered. A
linear basis in this space defines a basic set of the SPODs that are
necessary for the workpiece verification procedures: the SFE synthesis
followed by the best fitting procedure. The developed algorithms are
applied to the geometric accuracy assessments of multidimensional
features. The geometric accuracy of the ellipsoid of revolution is
simulated. Accuracy assessments, their uncertainty vs. distribution
functions, and processing time vs. sample size and the number of the
SPODs are evaluated.
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|
Diamond Tool Wear when Cutting Amorphous Polymers
|
|
G.P.H. Gubbels, G.J.F.T. van der Beek, A.L. Hoep, F.L.M. Delbressine (2), H. van Halewijn
|
|
STC P, 53/1/2004, P.447
|
|
Keywords: Wear, Polymer, Electrical discharge |
Abstract : Precision turning of polymeric materials increases form and
shape accuracies in respect to the conventional techniques, but the
relatively large tool wear of the mono-crystalline diamond tools may be
a problem. This paper will discus possible tool wear mechanisms that
occur during diamond turning of glassy (amorphous) polymers. Special
attention is given to thermal-oxidative tool wear, tribo-electric tool
wear and tribo-chemical tool wear. It will be shown that tribo-electric
and tribo-chemical tool wear play an important role in the precision
turning process of polymers.
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|
Measuring Form and Radius of Spheres with Interferometry
|
|
U. Griesmann, J. Soons, Q. Wang / D. De Bra (1)
|
|
STC P, 53/1/2004, P.451
|
|
Keywords: Interferometry, Form, Radius |
Abstract : The geometry of a nearly spherical surface, for example that
of a precision optic, is completely determined by the
radius-of-curvature at one point and the deviation from the perfect
spherical form at all other points of the sphere. We describe
measurements of radius and form error of a precision silicon sphere,
having a nominal radius of 46.8 mm, with the XCALIBIR interferometer at
the National Institute of Standards and Technology (NIST). For these
measurements XCALIBIR is configured as a spherical Fizeau interferometer
providing a field of view of 44°. To measure the radius, a variant of
the well known radius bench method is used. 138 overlapping areas of the
sphere surface are measured to determine the form error. A "stitching"
algorithm is then employed to assemble these measurements into a form
error map for the entire surface. We show that form errors can lead to
considerable uncertainty in the radius of sphere when obtained through a
measurement with the radius bench method.
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STC S |
|
Investigation on Color-Finishing Process Conditions for Titanium Alloy applying a New Electrical Grinding Process
|
|
H. Ohmori (2), K. Katahira, M. Mizutani, J. Komotori
|
|
STC S, 53/1/2004, P.455
|
|
Keywords: Electrical Grinding, High Quality Surface, Oxidation Process |
Abstract : Titanium alloy is usually colored by coating or painting after
finishing. Beyond that, however, if a stable oxide film can be
successfully and efficiently generated on the surface at the time of
grinding and polishing as part of surface processing, the surface
properties of the processed workpiece will be greatly improved. This
will also streamline surface treatment and allow for significant savings
in energy and procedures. This study proposes an electrochemical
processing system that organizes the thickness and structure of an oxide
film generated on the processed surface by applying a direct current of
extremely short pulses to the workpiece being ground. The authors
focused specifically on the color of the oxide film generated on the
processed surface as a result of optical interference, and studied
closely the mechanism and control of this color finishing process
conditions.
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|
Ultra-Precision Float Polishing of Calcium Fluoride Single Crystals for Deep Ultra Violet Applications
|
|
Y. Namba, N. Ohnishi, S. Yoshida, K. Harada, K. Yoshida / T. Matsuo (1)
|
|
STC S, 53/1/2004, P.459
|
|
Keywords: Ultra-precision polishing, atomic surface property, scanning probe microscopy |
Abstract : High purity calcium fluoride (111) single crystals were float
polished to a flatness of 32 nm p-v on 90-mm-diameter samples that had a
surface roughness of 0.72 nm Ry, and 0.077 nm rms, as measured with a
Scanning Probe Microscope (SPM). By observing an area of a
float-polished surface with a high resolution transmission electron
microscope, it was determined that the float-polished surface had a
perfect (111) lattice with small atomic steps, and no subsurface damage.
The polished surface roughness depends on the mismatch between the
sample surface and the (111) plane. This result was also verified by SPM
observation.
|
|
Effect of Slurry Selectivity on Dielectric Erosion and Copper Dishing in Copper Chemical-Mechanical Polishing
|
|
K. Noh, N. Saka, J.-H. Chun (2)
|
|
STC S, 53/1/2004, P. 463
|
|
Keywords: Chemical-Mechanical Polishing, Semiconductor Manufacturing, Integrated Circuits |
Abstract : A Formidable challenge in the present multi-step Cu CMP
process, employed in the ultra-large-scale integration (ULSI)
technology, is the control of wafer surface non-uniformity caused by
dielectric erosion and Cu dishing. A definitive understanding of the
causes of material loss and a physical model for non-uniformity in Cu
CMP are thus required. This paper examines the effects of slurry
selectivity on dielectric erosion and Cu dishing, in both single- and
multi-step Cu CMP processes, in terms of several geometrical and
physical parameters. Furthermore, optimal slurry selectivities to
mitigate dielectric erosion and Cu dishing in both single- and
multi-step polishing are suggested.
|
|
Effect of Chemical Composition upon Mechanical Properties of Thin Layered Mono-crystal SiC
|
|
A. Kakuta, Y. Furukawa (1)
|
|
STC S, 53/1/2004, P.467
|
|
Keywords: Single crystal silicon carbide, Mechanical properties, Physical vapor deposition (PVD) |
Abstract : To make thin layered mono-crystal silicon carbide on silicon
substrate, the hetero molecular beam epitaxial growth process is
promising, in which both silicon and carbon must be made incident as
their evaporated molecular states to silicon substrate. As there are
some methods of evaporating the material, there exist several
combinations that will considerably affect both the chemical and
mechanical properties of newly deposited layers. The present study
attempts to clarify the relationship between these chemical and
mechanical properties and determine the guidelines for the combination
and operating conditions in order to obtain the desired surface
properties through a series of tests and evaluations.
|
|
Non-Destructive and Non-Contact Determination of Layer Thickness and Thermal Properties of PVD and Sol-Gel Layers by Photothermal Methods
|
|
G. Goch (2), H. Prekel, S. Patzelt, G. Ströbel, D.A. Lucca (1), H.R. Stock, A. Mehner
|
|
STC S, 53/1/2004, P.471
|
|
Keywords: Coating property, Moulding tool, Photothermal radiometry |
Abstract : Thin layers in combination with metallic substrates are often
used for moulding tools. The layer properties depend on the coating
parameters and -technology (e.g. sol-gel, PVD, CVD). This paper presents
the photothermal measurement of layer thickness and thermal properties
of PVD and sol-gel layers which are needed for the development of
moulding tools. The influence of optical parameters and surface
roughness on the results is discussed.
|
|
Investigation of Sol-Gel Derived ZrO2 Thin Films by Nanoindentation
|
|
D.A. Lucca (1), M.J. Klopfstein, R. Ghisleni, A. Gude, A. Mehner, W. Datchary
|
|
STC S, 53/1/2004, P.475
|
|
Keywords: Coating, Hardness, Nanoindentation |
Abstract : The near surface mechanical response of multi-layer sol-gel
derived ZrO2 thin films has been investigated by nanoindentation. Five
layer sol-gel coatings deposited on AISI 304 stainless steel were
prepared by dip coating and subsequently heat treated at temperatures
ranging from 400-700 °C. Elastic modulus and hardness were measured at
depths corresponding to 7-10 percent of the film thickness. Heat
treatment temperature was found to have a significant effect on the
resulting near surface hardness and elastic modulus. Film structure was
also investigated by cross-sectional transmission electron microscopy
and electron diffraction, and was found to transition from an amorphous
ZrO2 phase to a combination of cubic and monoclinic phases as heat
treatment temperature was increased.
|
|
Wavelet Analysis for Surface Characterisation: an Experimental Assessment
|
|
A.A.G. Bruzzone (2), J.S. Montanaro, A. Ferrando, P.M. Lonardo (1)
|
|
STC S, 53/1/2004, P.479
|
|
Keywords: Surface Analysis, Roughness, Wavelet |
Abstract : A new approach based on wavelets for the mathematical
treatment of surface roughness is presented. Wavelet theory, firstly
developed for the analysis, compression and subband filtering in signal
processing, can be used as a tool for the treatment of profiles and
surfaces. In this paper the effectiveness of this new application is
discussed, considering either synthetic and real surfaces, with the aim
of evidencing the peculiarities of this methodology. Moreover, an
assessment of the descriptive capability of this approach to identify
the main features of the profile is given.
|
|
Phase Imaging in the Near Field
|
|
T. Mayes, M. Riley, K. Edward, R. Fesperman, A. Suraktar, U. Shahid, S. Williams / R. Hocken (1)
|
|
STC S, 53/1/2004, P.483
|
|
Keywords: Microscope, Scanning Probe Microscopy, Optical |
Abstract : The near-field scanning optical microscope (NSOM) circumvents
diffraction limited resolution imposed on ordinary optical microscopes.
We present a novel technique for obtaining simultaneous intensity,
topography, and phase images having a lateral resolution of a few tens
of nanometers for sample specimens ranging in thickness from a few
nanometers to more than one micron. The most recent system utilizes a
rotating mirror integrated with an environmentally stabilized, hybrid
(part optical fiber, part air path) Mach-Zehnder interferometer for
applications involving waveguide analysis, photoresist mask
characterization, and biological imaging. Instrument specifications
(software, hardware, and optical train) together with images obtained to
date are presented.
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