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CIRP ANNALS 2006 |
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STC A |
| A Kinematic Calibration Method for Industrial Robots Using Autonomous Visual Measurement |
| A. Watanabe (3), S. Sakakibara, K. Ban, M. Yamada, G. Shen /T. Arai (1) |
| STC A, 55/1/2006, P.1 |
| Keywords: Robot Calibration, Visual Measurement, Positioning Accuracy |
|
Abstract : Several new methods have been developed to achieve practical
accuracy for offline programming of robots and its applicability to the
real world. In this paper, a new kinematic calibration method is
proposed to automatically improve absolute positioning accuracy of
robots. Key points of the method include autonomous measurement and the
automatic generation of measuring poses. A new visual feedback motion
control method of the robot is proposed to achieve accurate measurement.
An algorithm is also proposed to improve the condition of measuring
poses automatically. The effectiveness of the proposed methods and
algorithm was investigated through experiments with actual robots. |
| Increasing Efficiency of Force-Controlled Robotic Assembly ?Design of Damping Control Parameters Considering Cycle Time? |
| T. Arai1 (1), N. Yamanobe, Y. Maeda, H. Fujii, T. Kato, T. Sato |
| STC A, 55/1/2006, P.7 |
| Keywords: Robot, Optimization, Force Control |
|
Abstract : Parameter tuning of force control to achieve operations
efficiently in robotic assembly is essential but time-consuming. In this
paper, an optimal set of parameters for damping control is computed,
which can reduce the cycle time of an assembly operation. The proposed
method is formulated as a nonlinear opti-mization using a dynamic
simulator based on 3D geometric model of assembled parts. The method is
ap-plied to clutch assembly for practical use. The results verify how
the operations can be sped up using the obtained parameters. The
proposed method enables users to introduce force control agilely. |
| Assembly of Hybrid Microsystems Using an Assembly System with 3D Optical Sensor |
| J. Hesselbach (2), K. Schöttler, R. Tutsch, M. Berndt |
| STC A, 55/1/2006, P.11 |
| Keywords: Assembly, Object recognition, Control |
|
Abstract : For the assembly of hybrid microsystems a high accuracy in the
range of a few micrometers is required. The combination of a parallel
robot with an integrated 3D vision sensor uses positioning marks on the
objects for object recognition. Within the assembly process, relative
positioning accuracies in the submicrometer range have been obtained.
Therefore, it is necessary to use a calibration strategy for matching
the coordinate system of the 3D vision sensor with the coordinate system
of the robot. The construction of the system, the calibration applied
and the positioning accuracy achieved by the robot will be discussed. |
| Transplanting Assembly of Carbon Nanotubes |
| S.G. Kim (2) |
| STC A, 55/1/2006, P.15 |
| Keywords: Assembly, Atomic force microscopy, Carbon nanotube |
|
Abstract : The manufacture of nanotechnology products requires assembly
of nano scale components to macro/micro-scale systems, which is a major
challenge in attempting to industrialize nanotechnologies. A new
approach to assemble nanostructures is developed with a control of
individual nanostructure?s location and alignment in a long-range order.
A concept of transplanting assembly has been developed to embed carbon
nanotubes into micro-scale polymer blocks, which then serve as carriers
for the embedded carbon nanotubes, facilitating the handling and
assembly of them. This technique includes vertical growth of carbon
nanotubes, nanopellet casting, planarization, nanopellet separation,
transplantation and bonding. This assembly technology can be broadly
applied to manufacture many nano scale products including carbon
nanotube tipped atomic force microscope probes. |
| Modeling and Control of Compliant Assembly Systems |
| S.J. Hu (2), J.A. Camelio |
| STC A, 55/1/2006, P.19 |
| Keywords: Assembly, Control, Dimensional |
|
Abstract : The assembly of compliant, non-rigid parts is widely used in
automotive, aerospace, electronics, and appliance manufacturing.
Dimensional variation is one important measure of quality in such
assembly. This paper presents models for analyzing the propagation of
dimensional variation in multi-stage compliant assembly systems and the
use of such models for robust design and adaptive control of assembly
quality. The models combine engineering structure analysis with advanced
statistical methods in considering the effect part variation, tooling
variation, as well as part deformation due to clamping, joining and
springback. The new adaptive control algorithm makes use of the fine
adjustment capabilities in new programmable tooling in achieving
reduction of assembly variation. |
| Variant-oriented Assembly Planning |
| H. Bley (2), C. Zenner |
| STC A, 55/1/2006, P.23 |
| Keywords: Assembly, Feature Technology, Variant Management |
|
Abstract : To remain competitive, companies have to fulfil the
requirements of their customers for individualised products of high
quality. Thus, they have to become capable of managing the continuously
rising number of product variants, especially in assembly planning. As
the current variant management concepts are not adequate, this paper
deals with a novel approach towards an integrated consideration of all
required product and process variants. A generalised product description
that can be enhanced with assembly features represents an optimal
initial point for assembly planning. The implementation of so-called
variant junctions allows for the regard of variants within the planning
of the required assembly processes. |
| Intelligent Assist Systems for Flexible Assembly |
| J. Krüger (1), R. Bernhardt (2), D. Surdilovic (3) /G. Spur (1) |
| STC A, 55/1/2006, P.29 |
| Keywords: Co-operative Assembly, Robot, Man-machine system |
|
Abstract : The growing number of product variants, smaller lot sizes,
reduced time to market and shorter lifecycles of products have lead to
increasing demands on automation equipment and concepts. As a solution,
hybrid human integrated approaches are proposed. The idea is to combine
human flexibility, intelligence and skills with the advantages of
sophisticated technical systems. Intelligent assist systems (IAS)
represent a novel class of assembly systems capable of working with
human operators in two modes: workplace sharing and time sharing. This
paper presents a novel collaborative robot system ("Cobot") capable of
sharing the workspace with the human co-worker and collaborating with
him through direct physical contact. |
| Development of a Duothermal Soldering Process |
| S. Consiglio, T. Fleschutz, G. Seliger (1), J. Seutemann |
| STC A, 55/1/2006, P.33 |
| Keywords: Soldering, Mounting, Process |
|
Abstract : For joining electric or electronic components and a printed
circuit board, mass soldering methods are mostly applied due to their
high productivity. In few cases selective soldering is required
concerning economical or technical issues. However, also established
selective soldering methods are incapable of reliably soldering
temperature sensitive components. The substrates or the elements often
cannot withstand the applied process temperatures of these methods. A
new selective soldering process, the Duothermal Soldering, was developed
which reduces heat input to the joint by employing low process
temperature and precisely dispensing solder. This process is based on
separating the application of heat to liquefy the solder and to heat the
elements to be joined. For the purpose of evaluation, a prototype has
been implemented and tested on flexible printed circuits and flexible
flat cables. |
| Selective Disassembly Sequencing: A Methodology for the Disassembly of End-of-Life Products |
| S. Kara, p. Pornprasitpol, H. Kaebernick (1) |
| STC A, 55/1/2006, P.37 |
| Keywords: Disassembly, Reuse, Environmental Impact |
|
Abstract : Disassembly planning has become an important strategic issue
in order to reduce the environmental impact and increase the value of
end-of-life (EOL) products. However, in order to make the recovery of
EOL products viable, optimal disassembly sequencing has to be determined
for each reusable component. In this paper, a selective disassembly
methodology for EOL products is presented, which was developed by
reversing and modifying the methodology developed by Nevins and Whitney
(1989) for assembly. In the new methodology, the disassembly sequence
generation and selective part recovery are largely performed by a
special computer software. A number of product case studies were used to
prove the concept and demonstrate the efficiency of the methodology. |
| Analysis of Reusability using 'Marginal Reuse Rate' |
| Y. Umeda, S. Kondoh, T. Sugino /H. Yoshikawa (1) |
| STC A, 55/1/2006, P.41 |
| Keywords: Lifecycle, Product Design, Reuse Rate |
|
Abstract : While reuse is an effective lifecycle option in terms of
reduction of environmental loads and value of reutilization, reuse has
inherent difficulties. Our naive question is why component reuse of home
appliances seems impossible while that of photocopiers succeeded. This
paper clarifies an essential factor for successful reuse; that is, the
balance between supply and demand of reusables, and proposes an index
named 'marginal reuse rate,' which indicates upper limit of reusability.
By using this index, reusability of several products is analyzed. The
marginal reuse rate indicates that design of lifecycle, in addition to
product design, is indispensable for successful reuse. |
STC C |
| 3D Finite Element Modelling of Segmented Chip Formation |
| J.C. Aurich (2), H. Bil |
| STC C, 55/1/2006, P.47 |
| Keywords: Machining, Finite Element Method, Segmented Chip Formation |
|
Abstract : This paper presents a 3D coupled thermo-mechanical finite
element model for the simulation of segmented chip formation in metal
cutting. For modelling, a commercial finite element code is used. The
generation of segmentation is achieved either by element erase with
respect to damage or by modification of material flow stress data; both
being coupled with continuous adaptive remeshing. A normalized
Cockroft-Latham model is utilized as the damage criterion for element
erase. Flow stress modification is achieved by using Rhim?s material
model. Fundamental observations from the simulations are concluded and a
guideline for further research is proposed. |
| Molecular Dynamics Simulation of Micro Mechanisms in Slip Deformation Theory of Crystals |
| T. Inamura (2), N. Takezawa, K. Yamada, K. Shibuya |
| STC C, 55/1/2006, P.51 |
| Keywords: Simulation,Microcutting,Single crystal |
|
Abstract : Based on the discussion that there should be a micromechanism
that causes a macroscopic slip of monocrystal copper, molecular dynamics
simulations with the analytical displacement field around a crack tip
have been carried out. The result of the simulation shows that
macroscopic shear slip in an f.c.c. monocrystal copper occurs as
discrete time events. This is because cross-slips occur in many places
in a material such that a macroscopic shear slip is blocked until some
critical state of the deformation. A macroscopic shear slip then occurs
suddenly at the critical state in which the area of disordered atomic
arrangement has stretched from one end of a crystal to the other end.
The reason why macroscopic shear slips occur in the directions of the
slip planes of a crystal is attributed to the fact that the areas of
disordered atomic arrangement develop only to those directions. |
| A New Burr Formation Model for Orthogonal Cutting of Ductile Materials |
| A.A. Toropov, S.L. Ko /J.M. Lee (1) |
| STC C, 55/1/2006, P.55 |
| Keywords: Burr, Model, Cutting |
|
Abstract : This paper proposes a new model to predict the full formation
of a burr in orthogonal cutting. The model is based on the theory of
slip-lines, the equilibrium equation, and experimental observations of
burr formation with relevant data gathered from previous studies. Unlike
with existing models, the proposed model considers the influence of the
deformation rate on burr formation as well as the compression factor of
the exit surface during burr development. A Mathcad program was created
based on the model. The program can visualize burr formation and can
predict the geometrical characteristics of the burr. The results of
visualization are presented in the paper. The influence of the tool rake
angle, the workpiece angle and the undeformed chip thickness, on burr
dimensions have been verified in experiments. The experimental results
show that the model is suitable in the cutting of ductile materials. |
| Five-axis Rough Milling Strategies for Complex Shaped Cavities based on Morphing Technology |
| B. Lauwers (2), P.P. Lefebvre |
| STC C, 55/1/2006, P.59 |
| Keywords: Computer aided manufacturing, Milling, Morphing |
|
Abstract : This paper describes the development of a 5-axis roughing
strategy for complex shaped cavities. The concept of morphing, commonly
known to calculate transitions between 2D pixel maps, has been further
developed to generate intermediate 3 dimensional roughing levels. In
addition, a fast and robust algorithm for the generation of gauge free
5-axis tool paths has been developed. Toroidal tools are used and the
tool orientation is optimised for maximal material removal. The newly
developed strategy eliminates the typical stairs shape, appearing after
conventional 2.5D roughing. Smoother finishing operations are thereby
enabled. The influence of cavity parameters like wall steepness on the
strategy performance is briefly discussed. |
| Investigation of Cutting Characteristics in Side-milling a Multi-thread Worm Shaft on Automatic Lathe |
| J.H. Ahn (2), D.B. Kang, M.H. Lee, H.Y. Kim, S.H. Kim, K.K. Cho (1) |
| STC C, 55/1/2006, P.63 |
| Keywords: Milling, Machinability, Worm |
|
Abstract : This paper investigates the cutting characteristics of
side-milling which is proposed as a more efficient way to manufacture
worms of higher accuracy than form-threading and planetary milling. A
tool-tip trajectory based on the tool-workpiece interaction is modelled
in terms of matrix transformation. Chip thickness, cutting force and
surface roughness are simulated using the calculated tool-tip
trajectories. The effects of various errors in the real cutting such as
run-out errors of a tool axis, tool setup errors and workpiece
deflection due to cutting forces are investigated. The simulation
results are verified through numerous experiments on an automatic lathe. |
| Impact Resistance of PVD Films and Milling Performance of Coated Tools at Various Temperature Levels |
| K.-D. Bouzakis (1), I. Mirisidis, N. Michailidis, G. Skordaris, E. Lili, A. Sampris, E. Pavlidou, G. |
| STC C, 55/1/2006, P.67 |
| Keywords: PVD coatings, impact test, wear |
|
Abstract : Impact tests were performed on coated cutting inserts,
revealing that a temperature increase, at first enhances the coating
impact resistance and then leads to its deterioration. On the other
hand, milling investigations with coated cemented carbide inserts
demonstrated that the cutting speed increase, up to a certain level,
causes initially a significant improvement of the cutting performance.
FEM calculations of the developed temperature and stress fields during
cutting provided additional insights. The joint study and the subsequent
correlation of the aforementioned results, renders the impact test as a
convenient and efficient methodology for the characterization of coated
tools? cutting performance. |
| Scientific Screening of Raw Diamond for an Ultraprecision Cutting Tool with High Durability |
| T. Yamaguchi, M. Higuchi, S. Shimada (1), H. Tanaka, K. Obata |
| STC C, 55/1/2006, P.71 |
| Keywords: Diamond, Turning, Wear |
|
Abstract : The wide scattering in tool life of natural mono-crystalline
diamond tools is considered to depend on intrinsic crystalline defects
due to nitrogen impurities in raw diamond. In this paper, the
correlation was investigated between the amounts and types of the
impurity evaluated by infrared absorption (IRA) and the crater wear and
chipping resistances. As a result, diamonds including less total amount
of impurity show larger wear resistance and that with larger amount of
B2-aggregates show larger chipping resistance. This suggests that the
inspection by IRA can be a useful method for screening of raw diamond
for highly durable cutting tools. |
| Chip Form Monitoring through Advanced Processing of Cutting Force Sensor Signals |
| R. Teti (1), I.S. Jawahir (1), K. Jemielniak (1), T. Segreto, S. Chen, J. Kossakowska |
| STC C, 55/1/2006, P.75 |
| Keywords: Chip Form Monitoring, Cutting Force Sensor, Advanced Signal Processing |
|
Abstract : This paper draws on the activities of the CIRP Collaborative
Work on ?Round Robin on Chip Form Monitoring? carried out within the
Scientific-Technical Committee Cutting (STC-C). This collaborative work
involved the following main round robin activities: (a) generation,
detection, storage and exchange of cutting force sensor signals obtained
at different Laboratories during sensor-based monitoring of machining
processes with variable cutting conditions yielding diverse chip forms,
and (b) cutting force signal (CFS) characterization and feature
extraction through advanced processing methodologies, both aimed at
comparing chip form monitoring results achieved on the basis of
innovative analysis paradigms. |
| Surface Integrity Difference between Hard Turned and Ground Surfaces and Its Impact on Fatigue Life |
| F. Hashimoto (2), Y.B. Guo, A.W. Warren |
| STC C, 55/1/2006, P.81 |
| Keywords: Surface, Fatigue, Hard Machining |
|
Abstract : Surface integrity is the key for process selection of hard
turning or grinding in industry. This study identifies the fundamental
differences in the integrity of hard turned and ground surfaces and the
subsequent impact on rolling contact fatigue life. The significant
findings are: (a) mechanical deformation plays a larger role during hard
turning than grinding, while the size effect in grinding induces higher
surface hardness; and (b) a hard turned surface may have a more than
100%37; longer fatigue life than a ground one with an equivalent surface
finish (Ra 0.07 µm) due to the very different characteristics of surface
integrity. |
| Modelling of Material Side Flow in Hard Turning |
| H.A. Kishawy (2), A. Haglund, M. Balazinski (1) |
| STC C, 55/1/2006, P.85 |
| Keywords: Turning, Modelling, FEM |
|
Abstract : In this paper an attempt has been made to model the material
side flow generated during hard turning operation. A three dimensional
thermo elasto-viscoplastic finite element model is presented. The model
incorporates cutting tools with different nose radii and cutting
conditions. The model was also used to investigate the effect of
different process parameters on the extent of material side flow. The
predicted results revealed that more side flow is generated when higher
nose radius is used. A similar observation is noted when lower feed is
used. The simulated results agreed well with the experimentally examined
machined surface, viewed with a scanning electron microscope. |
| Effects of Edge Preparation and Feed when Hard Turning a Hot Work Die Steel with Polycrystalline Cubic Boron Nitride Tools |
| L. Chen (2), T.I. El-Wardany, M. Nasr, M.A. Elbestawi (1) |
| STC C, 55/1/2006, P.89 |
| Keywords: Cubic boron nitride (CBN), Modelling, Turning |
|
Abstract : Polycrystalline cubic boron nitride (PcBN) is usually employed
in hard turning. Selection of optimum edge preparation is machining
parameter dependent. This paper investigates the effects of edge
preparation and feed on tool life and workpiece residual stresses. An
Arbitrary Lagrangian and Eulerian (ALE) finite element model was used to
explain tool wear rate and residual stress profile. Experimental results
showed that honed edges could be employed for hard turning when tensile
principal stresses in the tool were maintained at a low magnitude.
Chamfered edges produced less compressive residual stresses on the
surface. However, away from the machined surface, compressive residual
stresses penetrate deeper into the workpiece. |
| Improved Machinability in Hardmilling and Strategies for Steel Development |
| H. Chandrasekaran (1), R.M’Saoubi (2) |
| STC C, 55/1/2006, P.93 |
| Keywords: Machinability, Milling, Structural analysis |
|
Abstract : The synergetic advantage of tailoring alloyed steels to
improve their machinability in the hardened (30 ~55HRC) state is the
focus here. Results from milling tests and systematic study of steel
microstructure and tool wear mechanisms using high resolution microscopy
(FEG-SEM) and EDS clearly indicate that traditional machinability
improvement treatments are not always adequate here. In high alloyed hot
working steels, suitable primary carbides distribution could be better
than inclusion modification. In low alloyed steels secondary carbide
density appears to be critical and correlates well with machinability.
The study also points to strategies for steel development and their
efficient hard milling. |
| The Effect of Microstructure on Chip Formation and Surface Defects in Microscale, Mesoscale, and Macroscale Cutting of Steel |
| A. Simoneau, E. Ng, M.A. Elbestawi (1) |
| STC C, 55/1/2006, P.97 |
| Keywords: Micromachining, Chip, Surface |
|
Abstract : Chip and surface samples from microscale, mesoscale, and
macroscale cutting of 1045 steel revealed that workpiece microstructure
plays an important role in chip formation and the formation of surface
defects such as dimples. Heterogeneous finite element (FE) models at
different cutting scales were developed to investigate the effect of
microstructure on chip and surface dimple formation. Plastic strains
were found to increase as the scale of cutting decreased. Unlike a
conventional homogeneous FE model, a heterogeneous macroscale FE model
showed surface defects, and predicted plastic strains near double that
of a homogeneous model. |
| Variation in Machinability of Single Crystal Materials in Micromachining |
| S. Min, D. Dornfeld (1), I. Inasaki (1), H. Ohmori (2), D. Lee, M. Deichmueller, T. Yasuda, K. Niwa |
| STC C, 55/1/2006, P.103 |
| Keywords: Micromachining, Burr, Single crystal |
|
Abstract : For practical application of micromechanical machining, four
levels of process realization are required; fundamental understanding of
process physics, development of microplanning (processing parameter
optimization), macroplanning (tool path planning), and design
optimization. This study surveyed the influence of localized variation
in the microstructure on final process outcome and machinability of
brittle optical material in a ductile regime. A clear correlation
between burr height, critical depth of cut and crystallographic
orientation was found on single crystal materials (copper and magnesium
fluoride), giving insight into optimal orientations and process
parameters for acceptable micromachining process outcome. |
| Creation of Ultra-precision Microstructures with High Aspect Ratios |
| Y. Takeuchi (1), H. Suzukawa, T. Kawai, Y. Sakaida |
| STC C, 55/1/2006, P.107 |
| Keywords: Micromachining, Diamond milling, Microstructure |
|
Abstract : In recent years, ultra-precision micromachining technology has
been used in a variety of fields such as optical instruments, electronic
devices, medical equipments, etc. At present, it is essential to meet
the requirement of producing various shapes, one of which is a structure
with a high aspect ratio. Such structures are applied, for example, to a
shaft of micro robot, a long part of microactuator and micromachine, a
microneedle for syringe, etc. However, due to its fragile nature, it is
extremely difficult to fabricate the structure with a high aspect ratio
since it is easily damaged during cutting. It is intended to produce
micro towers with high aspect ratios by applying the ultra-precision
milling technology using a single crystal diamond cutting tool. The
method enables accurate creation of a variety of microstructures with
high aspect ratios. In addition, the study also proposes a new machining
method to create microneedle arrays, avoiding the contact of cutting
edge with already machined parts again. As a result, it is concluded
that the proposed method has the potential of producing a variety of
microstructures with high aspect ratios. |
| On the Effects of Residual Stresses Induced by Coated and Uncoated Cutting Tools with Finite Edge Radii in Turning Operations |
| J.C. Outeiro, A.M. Dias, I.S. Jawahir (1) |
| STC C, 55/1/2006, P.111 |
| Keywords: Machining, Residual Stress, Cutting Edge Radius |
|
Abstract : This paper presents an analysis of residual stresses in
turning of AISI 316L and AISI 1045 steels with coated and uncoated tools
having finite edge radii. An analytical predictive model, and
experimental techniques involving X-ray diffraction and IR thermal
imaging were used. Machining with coated tools produce higher
superficial residual stresses, larger tensile layer thickness and higher
residual stresses below the machined surface when using large cutting
edge radii at low feed rates. This effect is correlated with the
increase in the amount of heat conducted into the workpiece, and the
associated generation of high tensile residual stresses and severe
work-hardening. |
| Turning of advanced Ni based alloys obtained via powder metallurgy route |
| D.A. Axinte, p. Andrews, W. Li, N. Gindy, P.J. Withers /T.H.C. Childs (1) |
| STC C, 55/1/2006, P.117 |
| Keywords: Turning, Nickel alloy, Surface integrity |
|
Abstract : Nickel based alloys (RR_X) manufactured via powder route are
considered the next generation materials that can offer increased
efficiency of gas turbine engines. Their chemistry and mechanical
properties indicate even lower machinability than the current disc
alloys. The paper reports on specifics when rough and finish turning
these new Ni based alloys. Tool life, surface finish, workpiece surface
integrity and residual stress distributions have been used as
multi-objective quality criteria to assess the capability of shaping
RR_X alloys. The optimised cutting parameters/route was then employed to
produce surfaces in low cycle fatigue samples to demonstrate machining
capability to Airworthiness Authorities. |
STC Dn |
| A Uniform Approach for Utilizing Synergy between Inspection Technologies and Computational Methods |
| A. Miropolsky, A. Fischer (1) |
| STC Dn, 55/1/2006, P.123 |
| Keywords: Inspection technologies, Surface Reconstruction methods, Diverse scan data |
|
Abstract : Emerging scanning technologies currently capture diverse data
that includes geometrical and physical properties (i.e. normals,
material and color). Yet, existing inspection computational methods do
not satisfy industry demands. This paper proposes a new approach for
inherently handling diverse data and utilizing the synergy between
inspection technologies and digital processing methods. Two methods were
developed: a Hierarchical Space Decomposition Model (HSDM), which sorts
the sampled data, and a 3D Geometrical Bilateral Filter (3D GBF) that
utilizes the diverse data. These methods provide efficient data
reduction while preserving sharp features. The feasibility of this
approach is demonstrated on the diverse data. |
| Haptic Environment for Designing Human Interface of Virtual Mechanical Products |
| F. Kimura (1), N. Yamane |
| STC Dn, 55/1/2006, P.127 |
| Keywords: Virtual Prototyping, Haptic Interface, Simulation |
|
Abstract : For efficient and high-quality design of mechanical products,
it is now possible to use virtual product models as a basis for
functional simulation and verification. However it is not easy to
evaluate human operational interfaces of such virtual products only by
graphical interfaces. In this paper, a method is proposed to simulate
human operational interfaces by use of generic haptic devices. Based on
behavioural simulation of virtual product models, appropriate
information for haptic interaction is generated, and machine operational
interfaces are simulated by use of generic haptic devices. For
evaluating the effectiveness of the proposed method, assessment of
virtual mechanical switching operations has been performed. |
| What-if Design as a Synthesizing Working Method in Product Design |
| T.H.J. Vaneker, F.J.A.M. van Houten (1) |
| STC Dn, 55/1/2006, P.131 |
| Keywords: What-if design, Design support, Information management |
|
Abstract : What-if design attempts to support the designer by addressing
design problems, both in his own field ofexpertise, as well as from
adjoining domains. To this end, What-if design research focuses on
thedevelopment of methods and tools for real-time, in-process, design
support in order to enhance the searchfor optimal solutions. The main
advantage of this way of designer support is that the design can
beevaluated continuously on numerous fields of expertise, enabling the
optimization of the search for designsolutions.This paper focuses on a
bottom-up approach for What-if design and describes examples that
illustrate theworking methods chosen. |
| Competence Management for the Optimisation of Product Development Processes |
| F.-L. Krause (1), W. Hacker, U. Debitz, C. Kind, M. Strebel |
| STC Dn, 55/1/2006, P.135 |
| Keywords: Design, Process, Competence management |
|
Abstract : This paper presents a concept and a prototypical solution for
the management of competences of engineers working in product
development processes (PDP). Objectives are the representation of
individual personnel competences, their utilisation for PDP planning
activities such as the assignment of engineers to design tasks, and the
support of human resources development. Main result is an instrument for
the rational de-scription of the expertise needed to process new orders
and of the competencies of the engineering design-ers. The prototype
implementation of the approach is based on a graph based structure and
on rules repre-senting competence requirements of PDP and human
competence profiles, both processed by an interfer-ence mechanism. |
| A new Design Method based on Functions and Tolerance Specifications for Product Modelling |
| A. Ballu, H. Falgarone, N. Chevassus, L. Mathieu (1) |
| STC Dn, 55/1/2006, P.139 |
| Keywords: Design method, Product modelling, Functional tolerancing. |
|
Abstract : One of the major aims for aerospace industry is to manage
geometrical variations during assembly process and product lifecycle.
Since about ten years, new design methods have been proposed to consider
early functionalities and tolerance specifications but no one clearly
integrates the product modelling stage. To handle assemblies with
thousands of parts with many functional requirements, we have defined a
functional design method that early helps to identify and analyse
functional geometrical entities and tolerance specifications. The
proposed method integrates GASAP, a new approach for modelling as soon
as possible parts, assembly and tolerance specifications in a CAD
system. The method is supported by GAIA, a new software tool built on
assembly-nested graphs. |
| Linear Programming and Genetic Algorithms Methods for Creation of Groups in Networks of Excellence |
| G. Guttman, M. Shpitalni (1) |
| STC Dn, 55/1/2006, P.143 |
| Keywords: Knowledge management, Linear programming, Genetic algorithm |
|
Abstract : Creation of groups in Networks of Excellence (NoEs) based on
knowledge mapping and expertise is a set covering problem known to be
non-polynomial. Therefore it is usually approached by heuristic methods
which yield good but not necessarily optimal coverage. Selecting teams
to form a group within NoEs that are comprised of tens of teams can also
be formulated and solved as an integer linear programming (ILP) problem
whose solution is guaranteed to be optimal. This paper presents the ILP
solution for team selection with typical objective functions. Several
genetic algorithm-based methods are also compared to the optimal
solution in terms of convergence (time and solution). The compared
methods differ in selecting next-generation population |
| Risk Quantification for New Product Design and Development in a Concurrent Engineering Environment |
| B. Kayis, G. Arndt (1), M. Zhou, S. Savci, Y.B. Khoo, A. Rispler |
| STC Dn, 55/1/2006, P.147 |
| Keywords: Product Development, Concurrent Engineering |
|
Abstract : The challenges of product design and development in concurrent
engineering are analysed. Bayesian Belief Networks are applied to map
the relationships between risk events in a product?s life-cycle. This
approach enables the concurrency between risk items to be captured and
the cumulative effects of dependencies between risk events to be
determined. The inheritance of risks between different phases is modeled
and quantified, which is impossible by traditional project management
techniques. The combination of these factors has resulted in a
user-interactive, unique dynamic risk management software package, which
has been commercialised and deployed successfully by a major
international manufacturer. |
| Compatibility Measurement in Collaborative Conceptual Design |
| D. Kim, A. Bufardi, p. Xirouchakis (2) |
| STC Dn, 55/1/2006, P.151 |
| Keywords: Conceptual Design, Evaluation, Synthesis |
|
Abstract : A product consists of various sub-functions elaborated by
alternative design principles which results in many combinations. In
collaborative design, designers expect that their preferences over the
combinations be respected during the combination process of
sub-functions, resulting in compatible combinations. We formulate the
selection of compatible combinations as a combinatorial problem by: (i)
defining a design principle as a list of variables with their domain and
direction of designer¡¯s preferences, (ii) considering constraints among
design principles, (iii) characterizing the compatibility level of
combinations. A vacuum cleaner is considered with dust bag, plastic bin
or cyclonic design principles for the dust collection sub-function. |
| The Mind Process of Design Learned from the Revolving Door Accident |
| Y. Hatamura (1), K. Hattori, T. Hatamura |
| STC Dn, 55/1/2006, P.155 |
| Keywords: Man-machine system, Human, Measurement |
|
Abstract : In March, 2004, a boy ran into an automatic revolving door,
jammed his head and was killed at a skyscraper in Roppongi, Tokyo.
Yotaro Hatamura, as a citizen, formed and executed a project to uncover
the danger associated with ?doors? and to develop a guideline for their
safety. The project led to a design theory whose necessity had not been
recognized to the extent it deserved. This paper reports our findings
from the project about doors. The knowledge we gained through studying
the cause of the accident applies to a wide range of technology in general. |
| Design Reuse Method for Product Family Design |
| S.K. Ong (2), Q.L. Xu, A.Y.C. Nee (1) |
| STC Dn, 55/1/2006, P.161 |
| Keywords: Design reuse, Product evaluation, Information modelling |
|
Abstract : This paper presents a design reuse methodology to facilitate
product family design. Three major processes are defined, namely,
information modelling, information processing, and solution synthesis
and evaluation. The information content assessment (ICA) method is
proposed for solution evaluation. This method defines logical steps to
compute the information content that is used as a uniform, dimensionless
metric of product performances. In a case study, product families of the
cellular phone were developed using the design reuse methodology. It is
demonstrated that the design reuse method proposed in this paper can
effectively manage the product family design processes, and the ICA
method provides a useful way for performance evaluation. |
STC E |
| Machining Characteristics of EDM by Radio-frequency Plasma |
| A. Okada, J.A. McGeough (1), D. MacMillan, B. Flynn |
| STC E, 55/1/2006, P.167 |
| Keywords: Electrical Discharge Machining (EDM), Silicon, Surface |
|
Abstract : An extension to the Electro-discharge Machining (EDM) method
by introduction of radio-frequency generated plasma is proposed. The
radio-frequency plasma can be readily generated between a tool electrode
and a work piece in air; moreover sparking can be generated in paraffin
oil by simple electrical circuitry. A form of machining similar to that
of EDM in paraffin oil may then be achieved In this paper, experimental
investigations are described on the fundamental effects of the resonant
frequency, type of electrode material and radio-frequency power on
machining characteristics such as the removal rate, the electrode wear
and the surface roughness in order to establish high performance
radio-frequency machining in paraffin oil. In addition, experiments on
radio-frequency machining of silicon and titanium are discussed. These
results show that the removal rate and the electrode wear vary with the
resonant frequency and type of electrode materials. The surface
roughness can be reduced to less than 1micronRz under suitable
experimental conditions. Monocrystalline silicon of low resistivity and
titanium alloy can be also machined by radio-frequency machining.
Results on tests with these latter materials are also described. |
| Diffusion Bonded EDM Electrode with Micro Holes for Jetting Dielectric Liquid |
| T. Shibayama, M. Kunieda (2) |
| STC E, 55/1/2006, P.171 |
| Keywords: EDM, Electrode, Electrochemical Jet Machining |
|
Abstract : This paper describes improvement of machining characteristics
of electrical discharge machining of deep slots using a tool electrode
which has micro holes for jetting dielectric liquid over the working
surface. The tool electrode was made by the diffusion bonding of two
copper plates, over an interface on which micro grooves for jetting the
dielectric fluid were formed using electrolyte jet machining. In
conventional machining, it is difficult to drill micro holes at the end
of a slim electrode and circulate the dielectric fluid from the other
end. Hence a solid tool electrode is used and periodically lifted up
during machining to flush debris particles out of the discharge gap. Use
of the newly developed tool electrode was found to shorten the
processing time and improve machining accuracy significantly compared
with the conventional solid tool electrode. Since the holes are micro,
the outlet shapes are not replicated onto the bottom surface of the slot
machined. |
| Micro-pin Electrodes Formation by Micro-Scanning EDM Process |
| N. Mohri (1), T. Tani |
| STC E, 55/1/2006, P.175 |
| Keywords: Electrical Discharge Machining, Micromachining, Scanning Electrode |
|
Abstract : In recent micro-EDM processes various kinds of thin tool
manufacturing methods, including the wire electrical discharge grinding
(WEDG) have been proposed to satisfy the growing need for very thin
tools. This study describes a new thin tool micro-formation by EDM where
a rod electrode is driven through the center of a controlled slit formed
between two electrically isolated metal plates to provide a critical
path for the rod electrode tool during the process. A micro-pin of the
desired shape and diameter is obtained, under stable conditions, in a
very short time interval. |
| Sequential Laser and EDM Micro-drilling for Next Generation Fuel Injection Nozzle Manufacture |
| L. Li (2), C. Diver, J. Atkinson, R. Giedl-Wagner, H.J. Helml |
| STC E, 55/1/2006, P.179 |
| Keywords: Laser micro machining, Electrical discharge machining (EDM), Drilling |
|
Abstract : High quality holes of diameters less than 145 µm are required
for the manufacture of next generation diesel fuel injection nozzles for
improved combustion efficiency and reduction of emission to the
environment. The current practice of using electro-discharge machining
(EDM) drilling of fuel injection nozzles is limited in terms of the hole
size it can produce effectively and the length of time needed to drill.
In addition, the tooling cost is high. This paper reports on an
investigation into a sequential laser and EDM micro-drilling technique
for the manufacture of next generation fuel injection nozzles. A
laser-drilled pilot hole is rimmed out by EDM drilling. It was found
that this hybrid process has eliminated the problems of recast and heat
affected zones typically associated with the laser drilling process. The
new process has enabled a 70%37; reduction in total drilling time compared
to standard EDM drilling as less material is removed by the EDM. The
quality of the holes is as good as direct EDM drilling, thus eliminating
the need for re-certification of the drilling process. Various
combinations of laser/EDM drilling conditions have been examined.
Optimum diameters for the pilot hole and the EDM electrode have been
identified for a particular diameter of fuel injection nozzle, giving
the minimum total drilling time and the best quality holes. A special
system was designed to enable the alignment of nozzles to be controlled
to within ± 20 ?m. The technique has enabled valuable cost savings and
increase in production capacity for next generation fuel injection
nozzle manufacture. |
| Surface Microstructures obtained by Femtosecond Laser Pulses |
| M.N.W. Groenendijk, J. Meijer (1) |
| STC E, 55/1/2006, P.183 |
| Keywords: Laser, Micromachining, Surface texture |
|
Abstract : After machining of steel by femtosecond laser ablation
unexpected surface structures are found at the bottom of the machined
area. Periodic sub-micrometer spaced ripple patterns are formed after
irradiation with several pulses. At a certain number of incident pulses
the ripples starts to break up resulting in a more chaotic structure.
The point of transition and the morphology of the chaotic structure
depend on several parameters. The paper describes the ripple formation
and the resulting surface structures dependent on the repetition
frequency of the laser and the number of incident pulses. |
| Fundamentals of Selective Laser Melting of Alloyed Steel Powders |
| M. Rombouts, J.P. Kruth, L. Froyen, p. Mercelis |
| STC E, 55/1/2006, P.187 |
| Keywords: Selective Laser Melting (SLS), Powder, Alloy |
|
Abstract : The successful fabrication of dense iron-based parts by
selective laser melting (SLM) is still limited to a narrow range of
materials. This study aims at gaining an understanding in the effect of
elements such as oxygen, carbon, silicon, titanium and copper on the
quality of two-dimensional and three-dimensional iron based objects. The
results are related to the effect of the elements on physical phenomena
such as laser absorption, heat transfer, wetting and spreading of the
melt, oxidation, Rayleigh instability and Marangoni convection. An
in-process observation system based on high speed imaging is used to
improve the understanding of the melt pool dynamics. |
| Abrasive Polishing Assisted Nickel Electroforming Process |
| D. Zhu (2), Z.W. Zhu, N.S. Qu |
| STC E, 55/1/2006, P.193 |
| Keywords: Deposition, Nickel, Hybrid |
|
Abstract : This paper presents a hybrid process combining electroforming
technique and abrasive polishing. In a specifically developed equipment
the spherical ceramic particles between the cathode mandrel and the
anode are forced to continuously polish the deposition surface during
nickel electrodepositing. The abrasive polishing can effectively remove
the pinholes and nodules, and positively affect the crystal nucleation
and therefore refine the grains and speed up the deposition process.
Smooth deposition surface of Ra 0.012 ?m, compact nickel deposits with
the grain size of less than 80nm and the significantly improved
mechanical properties have been experimentally obtained. |
| The Effects of Tool Electrode Size on Characteristics of Micro Electrochemical Machining |
| B.J. Park, B.H. Kim, C.N. Chu (2) |
| STC E, 55/1/2006, P.197 |
| Keywords: Electro chemical machining (ECM), Micromachining, Electrode insulation |
|
Abstract : In micro electrochemical machining using ultra short pulses,
the machining rate is significantly influenced by the tool electrode
area. As the tool area increases, the electrical double layer
capacitance increases and the electrolyte resistance decreases. As a
result, the rising time of the double layer potential increases and it
is more difficult to obtain effective machining potential within the
ultra short pulse duration. A simple insulation method using enamel
coating on the side wall of the tool electrode is introduced. The
insulated tool electrode was not sensitive to the machining depth and
was effective for machining high aspect ratio structures. |
| Influence of Debris Accumulation on Material Removal and Surface Roughness in Micro Ultrasonic Machining of Silicon |
| Z. Yu, X. Hu, K.P. Rajurkar (1) |
| STC E, 55/1/2006, P.201 |
| Keywords: Micro Machining, Ultrasonic, Roughness |
|
Abstract : Although micro ultrasonic machining (USM) has been
successfully applied in generating micro features in hard and brittle
materials such as silicon, the influence of machining parameters on the
machining performance is not clearly understood. Experimental results
show that the machining speed decreases with an increase in the static
load beyond a certain level. In this study, the debris accumulation is
proposed as the main reason leading to low machining efficiency. A
mathematical model is also developed to analyze this phenomenon
qualitatively. Experimental results reveal that the particle size is the
dominate factor influencing the surface roughness in micro USM. |
| An Economic, Environment-friendly Oxygen-Hydrochloric Acid Regeneration System for Ferric Chloride Etchants used in Photochemical Machining |
| D.M. Allen (2), P. Jefferies |
| STC E, 55/1/2006, P.205 |
| Keywords: Environmental, Etching, Photochemical machining |
|
Abstract : This paper describes the implementation of a low-cost,
environment-friendly, oxygen-based regeneration system into a commercial
etching line. The system has been investigated from both technical and
economic viewpoints. It has been demonstrated to be cheaper than
alternative regeneration techniques but it is only feasible when etchant
parameters are monitored and controlled on-line to prevent the
precipitation of ferrous salts. From analysis of the system, it was
discovered that the most important parameter to control is the etchant
pH. This not only influences the ability to regenerate but also dictates
the resultant surface finish of the etched product. |
| Effect of Surface Roughness on Droplet Bouncing in Droplet-Based Manufacturing Processes |
| W-K. Hsiao, J.-H. Chun (1), N. Saka |
| STC E, 55/1/2006, P.209 |
| Keywords: Rapid prototyping, Soldering, Surface Roughness |
|
Abstract : In droplet-based manufacturing processes, such as drop-wise
rapid prototyping, solder bumping and spray forming, the bouncing
phenomenon adversely affects the quality of the deposit. This study
investigates the effect of surface roughness on bouncing of liquid metal
droplets from the substrate. An analytical model was developed to
correlate the surface roughness with a non-dimensional droplet bouncing
potential. In addition, and experimental study was conducted to image
the deposition behavior of Pb-37wt%37; Sn solder droplets, 280 micrometers
in diameter, on Au-plated substrates with a wide range of surface
roughness. The high-speed image data correlate well with the model
prediction that droplet bouncing increases as surface roughness increases. |
| Liquid-phase Infiltration of Thermal Sintered Skeletons by Low-temperature Gold Eutectic Alloys |
| M. Lanzetta /M. Santochi (1) |
| STC E, 55/1/2006, P.213 |
| Keywords: Powder, Sintering, Infiltration |
|
Abstract : The flexibility of powder-based Rapid Prototyping (or Solid Free Form
Fabrication) techniques and the densification method described in this
paper would open a whole new range of applications where thermal
constraints exist. This work examines the infiltration of sintered
skeletons made of pure gold spherical powder ranging between 5 and 40 ?m
in size, by binary gold eutectics based on silicon, germanium and tin,
with a melting point as low as 278° C. Experiments have shown that high
densification rate, good surface finish and improved mechanical
properties can be achieved with this process. The material properties
influencing the process performance are pointed out. |
| Investigations on New Scanning Pattern for Stereolithography |
| K.K.B. Hon (1), C. Han, S.P. Edwardson |
| STC E, 55/1/2006, P.217 |
| Keywords: Stereolithography, Accuracy, Scanning |
|
Abstract : The basic layer-based manufacturing mechanism of
stereolithography is built upon a scanning pattern for the entire cross
section for each layer. In this investigation, a new schema of scanning
is proposed and its effects on dimensional accuracy and surface profile
are benchmarked against an industry standard scanning pattern.
Experimental results show that the new scanning pattern offers further
improvements in terms of dimensional accuracy and geometrical profile as
supported by a higher value of process capability index Cpk. The use of
Finite Element method to simulate the new scanning pattern is also
described in order to provide an analogous insight on process effects
and residual stress distribution. |
| Computer Simulation of Stereolithographic Curing Reactions: Phenomenological versus Mechanistic Approaches |
| P.J. Bártolo /E. Lenz (1) |
| STC E, 55/1/2006, P.221 |
| Keywords: Finite element method, Modelling, Stereolithography |
|
Abstract : A new phenomenological modelling approach to study, simulate
and optimise the curing processes of thermosetting materials for
stereolithographic processes is proposed. The model was developed for
light-initiated, thermal-initiated, light-initiated accelerated by heat,
and light and thermal-initiated systems. This model includes the effects
of initiator concentration, temperature and light intensity, predicting
the diffusion-controlled effects that occur after vitrification, the
phenomenon of unimolecular termination and the shrinkage effects. The
model is numerically implemented through the finite element method and
solved using both the Galerkin method for spatial approximation and the
Crank-Nicolson method for temporal approximation. The model was
experimentally verified showing a good correlation between experimental
and predicted values. |
STC F |
| Characterisation of the Flow Properties of the Quenchenable Ultra High Strength Steel 22MnB5 |
| M. Merklein, J. Lechler, M. Geiger (1) |
| STC F, 55/1/2006, P.229 |
| Keywords: Forming, Mechanical Properties, Hot stamping |
|
Abstract : Nowadays in the automobile industry more and more high
strength steels find their application. For their processing innovative
forming technologies, like the non-isothermal hot stamping process, are
required. With regard to a reliable numerical process design the
knowledge of the thermal and thermo-mechanical properties is essential.
Within this paper an experimental setup will be introduced, which
enables the determination of the material?s flow behaviour according to
the hot stamping time-temperature-characteristics. Further results of
investigations on the thermo-mechanical flow properties of the
quenchenable, ultra high strength steel 22MnB5 in dependency of the
temperature, the strain and the cooling rate etc. will be represented. |
| Combined Mechanics-Materials Based Optimization of Superplastic Forming of Magnesium AZ31 Alloy |
| M.K. Khraisheh, F.K. Abu-Farha, M.A. Nazzal, K.J. Weinmann (1) |
| STC F, 55/1/2006, P.233 |
| Keywords: Sheet Metal, Magnesium, Superplastic Forming |
|
Abstract : A new optimization approach for superplastic forming of Mg
AZ31 alloy is presented and experimentally validated. The proposed new
optimization approach is based on a multiscale failure criterion that
takes into account both geometrical necking and microstructural
evolution, yielding a variable strain rate forming path instead of the
commonly used constant strain rate approach. Uniaxial tensile tests and
free bulge forming experiments, in conjunction with finite element
analysis, are used to evaluate the proposed optimization approach.
Significant reduction in forming time is achieved when following the
proposed optimization approach, without compromising the uniformity of
deformation. |
| Force Reduction in Bending of Thick Steel Plates by Localized Preheating |
| J.R Duflou (2), R. Aerens |
| STC F, 55/1/2006, P.237 |
| Keywords: Bending, Plates, Preheating |
|
Abstract : A trend towards higher tonnage press brakes, suitable for
processing thick plates, can be observed. In this paper a dynamic method
for preheating of thick steel plates, limited to the bending area, is
presented, facilitating bending with a significantly reduced total
force. The dynamic heating method thus allows to substantially extend
the process window of press brakes. The method was experimentally tested
on low carbon steel plates, characterised by a relatively high required
temperature rise in order to achieve a favourable yield behaviour. A
prototype setup developed for this purpose is described. Reported test
results include achievable temperature distributions, force measurements
as a function of temperature and spring back measurements. A derived
simulation model allows to extrapolate the results to higher thickness
plates. |
| Single Point Incremental Forming and the Forming Criteria for AA3003 |
| M. Ham, J. Jeswiet (1) |
| STC F, 55/1/2006, P.241 |
| Keywords: Forming, Sheet metal, Incremental Forming |
|
Abstract : Single Point Incremental Forming (SPIF) is a modern method of
forming sheet metal, where parts can be formed without the use of
dedicated dies. The ability of SPIF to form a part is based on various
forming parameters. Previous work was not accomplished with the help of
design of experiments, thus reducing the number of parameters varied at
any time. This paper presents two designs of experiments, which
formalise the forming parameters critical in SPIF and the degree to
which they affect formability |
| On-Line Control of Single Point Incremental Forming Operations Through Punch Force Monitoring |
| L. Filice, G. Ambrogio, F. Micari (1) |
| STC F, 55/1/2006, P.245 |
| Keywords: Sheet metal forming, Force monitoring and control, Incremental Forming |
|
Abstract : Among the innovative sheet metal forming processes, Single
Point Incremental Forming (SPIF) represents the simplest and the
cheapest one. Despite its relevant advantages, up to now no specific CAE
tools for SPIF were developed and the tool trajectory is generally
defined utilizing CAD/CAM software developed for machining applications.
In the paper an innovative monitoring and control approach, aimed to
define and in-process update the most relevant process parameters during
an industrial SPIF operation, is proposed. The strategy utilizes as
monitoring variable the punch force trend: a set of preliminary tests
demonstrated, in fact, its suitability as ?spy variable? of the process
mechanics and, in particular, of excessive sheet thinning and material
failure approaching. |
| Optimal Programming of Multi-point Cushion Systems for Sheet Metal Forming |
| H. Palaniswamy, M. Braedel, A. Thandapani, T. Altan (1) |
| STC F, 55/1/2006, P.249 |
| Keywords: Finite element method (FEM), Sheet metal, Optimization |
|
Abstract : Numerical optimization technique coupled with finite element
analysis of the stamping/sheet hydroforming process was developed to
predict four possible modes for application of blank holder force (BHF)
in multiple-point cushion systems, namely a) BHF constant in
space/location and time/stroke, b) BHF variable in time/stroke and
constant in space/location, c) BHF variable in space/location and
constant in time/stroke and d) BHF variable in space/location and
time/stroke. The BHF was predicted by (a) minimizing the risk of failure
by tearing (thinning) in the formed part and (b) avoiding wrinkling. The
developed technique was applied to predict the BHF to form a) an
automotive part (liftgate-inner) from AA6111-T4 aluminum alloy, b) an
asymmetric part from aluminum alloy AA5083-H32 by sheet hydroforming
process with die (SHF-D) and c) a round cup by sheet hydroforming with
punch (SHF-P). Experimental results showed that the FEM based
optimization methodology can reduce trial and error effort and is able
to predict the blank holder force necessary to form the parts without
fracture and wrinkling in the investigated stamping and sheet
hydroforming operations. |
| Piercing of Steel Sheet by using Hydrostatic Pressure |
| M. Shiomi, Y. Ueda, K. Osakada (1) |
| STC F, 55/1/2006, P.255 |
| Keywords: Hydroforming, Hydrostatic, Piercing |
|
Abstract : In order to improve the dimensional accuracy of the hole made
by piercing a sheet/tube in hydroforming, some piercing methods using
hydrostatic pressure are examined. In piercing by pushing a steel sheet
into the pressurised liquid with a punch, the sheet is warped and the
edge of the hole sinks (edge drop). In piercing by pushing the sheet
outwards with hydrostatic pressure while the punch recedes, warping is
suppressed but burr is formed. When the sheet is first pushed with the
punch into the liquid and then piercing is completed by receding of the
punch, burr is not formed and edge drop decreases by about 50%37;. |
| Fundamentals of Angular Joining by means of Hydroforming |
| P. Groche (2), K. Tibari |
| STC F, 55/1/2006, P.259 |
| Keywords: Hydroforming, Structure, Joining |
|
Abstract : Joining hollow tubular profiles, employing internal pressure
and using the springback characteristics of different materiels, is
state of the art. However, this technique is limited to coaxial oriented
parts, i.e. camshafts. The joining of angular oriented workpieces is not
possible, by only applying shrink fit mechanisms. This paper introduces
a methodology to join tubular profiles in order to create frame
structures and to shape them, simultaneously. The workpieces hold
together because of a force fit. Experiments are conducted to verify the
methodology. Physical phenomena are exlained by means of analytical and
numerical analysis. |
| Tensile Test of very thin Sheet Metal and Determination of Flow Stress Considering the Scaling Effect |
| H. Hoffmann (2), S. Hong |
| STC F, 55/1/2006, P.263 |
| Keywords: Tensile Test, Sheet Metal, Miniaturization |
|
Abstract : The reduction in size of mechanical parts is becoming more and
more important in metal forming processes. This trend towards
miniaturization leads to new requirements regarding the material and the
product. The main object of this research is the so-called scaling
effect which can occur during the forming process of very thin sheet
metals. The goal is to determine and investigate variables which
considerably influence the scaling effect. The optimisation of such
forming processes needs a more comprehensive use of simulation and
finite element analysis. The conventional model used for large and thick
sheet specimens is not sufficient yet. Existing research reports on this
topic show that among other things the thickness and the grain size of
the material influence the scaling effect. Thus it is important to
consider these material characteristics in the determination of the flow
stress curve. In this paper the flow stress curve is investigated on a
micro scale of up to 10µm specimen thickness considering different sheet
thicknesses and widths. |
| Determination of Flow Curves at High Strain Rates using the Electromagnetic Forming |
| M. Kleiner (1), A. Brosius |
| STC F, 55/1/2006, P.267 |
| Keywords: Finite element method, Parameter identification, Electromagnetic forming |
|
Abstract : The knowledge of reliable material parameters is an essential
requirement for the numerical analysis and planning of forming
processes, especially when using high speed forming processes in
industry. Therefore, a method was developed and implemented to determine
the relationship between yield stress, plastic strain, and strain rate
of aluminium alloys at very high strain rates of up to 10,000 s-1 by
using the electromagnetic forming process (EMF) of tubular specimens. To
determine the associated flow curves, an inverse engineering strategy
combining an online measurement technique and multi-physical coupled
finite element simulations is used. The results are discussed with
regard to the anisotropic behaviour of specific aluminium alloys. |
| Controlling the Cold Roll Forming Design Process |
| D.J. Mynors, M. English, M. Castellucci /A.N. Bramley (1) |
| STC F, 55/1/2006, P.271 |
| Keywords: Sheet, Design, Cold roll forming |
|
Abstract : The cold roll forming process requires successive forming
profiles to be determined and an appropriate number of profiled roll
sets to be designed for the product to be rolled. This paper examines
the design process and how one company has put in place a
design-production control system that allows designs to be ranked in
terms of quality and efficiency. In addition, consideration is given to
the proportion of time given to each design task and how non-creative
design activities can be automated. |
| Effect of Extrusion Conditions on Metal Flow and Microstructures of Aluminum Alloys |
| T. Ishikawa, H. Sano, Y. Yoshida, N. Yukawa, J. Sakamoto, Y. Tozawa (1) |
| STC F, 55/1/2006, P.275 |
| Keywords: Extrusion, FEM, Microstructure |
|
Abstract : Study of metal flow in extrusion billet is fundamental and
useful to understand extrusion technology. Investigation of behavior of
extrusion billet skin and microstructure of products is indispensable to
maintain qualities of extrusions. In order to research the behavior,
experiments and FE analysis of clad billet extrusion were performed. The
analytical results of billet skin deformation were similar to that in
experiments. Friction between back end of billet and ram affects the
deformation of skin and its penetration into billet. Secondly,
microstructure of an extruded product is predicted and the condition of
recrystallization and grain refinement is revealed. |
| Friction Stir Welding of Tailored Blanks: Investigation on Process Feasibility |
| G. Buffa, L. Fratini (2), J. Hua, R. Shivpuri (2) |
| STC F, 55/1/2006, P.279 |
| Keywords: Friction Stir Welding (FSW), Material Flow, FEM |
|
Abstract : Tailor welded blanks (TWBs) are conventionally produced by
laser or traditional welding processes. In either case, the joints are
created by solid-liquid-solid phase transformations that result in
undesirable microstructures and tensile residual stresses detrimental to
joint performance. This study investigates feasibility of an alternate
joining process, friction stir welding (FSW). The joining of AA7075-T6
blanks of different thickness is investigated through FE analyses and
controlled experiments. It is found that for a successful joint, the
welding parameters have to be carefully designed so that the resulting
metal flow and the temperature history during FSW are consistent for the
two thicknesses. |
| Plastic Joining of Ultra High Strength Steel and Aluminium Alloy Sheets by Self Piercing Rivet |
| K. Mori (2), T. Kato, Y. Abe, Y. Ravshanbek |
| STC F, 55/1/2006, P.283 |
| Keywords: Sheet metal, Plastic joining, Self piercing rivet |
|
Abstract : Ultra high strength steel and aluminium alloy sheets were
plastically joined by a self piercing rivet driven through the upper
sheet and spread in the lower sheet with a die. The self piercing rivet
directly pierces into the sheets without drilling the sheets beforehand
unlike the conventional rivets. Insufficient driving though the upper
sheet and fracture of the lower sheet occur due to the high hardness and
low ductility of the ultra sheet, respectively. An ultra high strength
steel sheet having a tensile strength of 980MPa and an aluminium alloy
sheet were successfully joined by optimising shapes of the die. |
| Physical Simulation of Longitudinal Welding in Port-Hole Die Extrusion |
| P.F. Bariani, S. Bruschi, A. Ghiotti |
| STC F, 55/1/2006, P.287 |
| Keywords: Extrusion, Welding, Simulation |
|
Abstract : In porthole-die extrusion, the metal flowing through the die
has to split up around the webs and then rejoin creating longitudinal
welds that extend along the whole profile. The formation and quality of
these welds depend on the metal flow around the webs and a number of
process parameters such as the thermal and mechanical history stored in
the material in the welding area and the temperature and pressure in the
welding chamber. The paper presents a new laboratory test principle
based on physical-simulation experiments on real materials that proves
to be particularly suitable for investigating and modelling longitudinal
welds in hot extrusion. In the test, the conditions governing the
formation of longitudinal welds in the real industrial process are
accurately reproduced and the process parameters affecting the quality
of the welds can be individually controlled as well. The results
achieved in applications of the test to aluminum alloy AA 6060 are
presented with a focus on the operating conditions in the welding
chamber that determine the transition from partial to complete
longitudinal welding. |
| Tribological Size Effects in Sheet Metal Forming Measured by a Strip Drawing Test |
| F. Vollertsen (2), Z. Hu |
| STC F, 55/1/2006, P.291 |
| Keywords: Friction, Sheet metal, Scaling |
|
Abstract : The aim of this work is to identify the tribological size
effects within sheet metal forming and to develop a size-dependent
friction function for the integration in the FEM-simulation. A strip
drawing test with deflection in combination with a numerical
identification is used. The numerical identification is based on an
analytical model for the punch force and an optimisation program, which
identifies the friction coefficient in dependence on the contact
pressure from the measured punch force vs. punch travel. Scaled
experiments with sheet thicknesses from 0.02 mm to 2 mm were done to
identify the tribological size effects. |
| Lubrication for Micro Forming of Ultra Thin Metal Foil |
| S.W. Baek, S.I. Oh (1), S.H. Rhim |
| STC F, 55/1/2006, P.295 |
| Keywords: Micro forming, Lubrication, Wafer die |
|
Abstract : The objective of the present investigation is to establish
lubrication technique in micro forming operation. Conventional
lubricant, in general, cannot be applied directly to micro forming
process, since the lubricant thickness is similar to the dimensions of
feature size in micro forming operations. In present investigation, the
Octadecyltrichlorosilane (OTS) self-assembled monolayer (SAM) was chosen
as a potential lubricant because it sticks to Si wafer die and can be
applied to surface with uniform thickness of several nanometer thick.
Friction coefficient and adhesion force were measured for OTS SAM coated
wafer. It is shown that OTS SAM coated Si wafer offers substantially
lower friction and lower adhesion than bare Si wafer. Micro channel
wafer die was coated with OTS SAM and channel forming operation with 1?m
thick copper foil was carried out. Experimental results show that OTS
SAM coated wafer die improves forming characteristic of ultra thin
copper foil substantially. These results show that SAM coating can be
used as a lubricant in micro forming successfully. |
| Spreading Behavior of Water Based Graphite Lubricants on Hot Die Surfaces |
| L. Yang, R. Shivpuri (2) |
| STC F, 55/1/2006, P.299 |
| Keywords: Lubrication, Die, Forging |
|
Abstract : In hot forging, water-based-graphite lubricants are sprayed on
the die surface to provide a thin adherent graphite film for the desired
metal flow. The film formation depends on the spread of the lubricant
droplets and their dry-off. With dryoff-times being very small, the
spreading is essentially isothermal. Therefore, the fundamentals of
spreading droplets are investigated through droplet mechanics and the
similarity principles. Relations are derived between the spray
parameters and the non-dimensional spread coefficient using single
droplet experiments. These relations together with measured rheological
properties are used to predict spread ratio for the various lubricant
dilution ratios using validated numerical models. |
| Effects of Plastic Strain on Surface Roughness and Coefficient of Friction in Tension-Bending Test |
| A. Azushima (2), M. Sakuramoto |
| STC F, 55/1/2006, P.303 |
| Keywords: Friction, Roughness, Deep drawing |
|
Abstract : In order to make investigation into the tribological behaviors
at the interface between tool and workpiece in the die corner of deep
drawing, a tension-bending type test was used. A new tension-bending
type test in which constant back tensions were applied and the
deformation of specimen was plastic was developed. The workpiece used
was an aluminum sheet with a smooth surface. The tests were carried out
at a constant speed under various back tensions using a lubricant. The
drawing force was measured during test and after tests the surface
roughness of specimen was measured. In the lower average contact
pressure, the surface roughening was predominant and the coefficient of
friction was constant. On the other hand, in the higher average contact
pressure, the flattening of surface asperties is predominant and the
coefficient of friction decreased with increasing average contact pressure. |
STC G |
| Magnetorheological Jet Finishing of Conformal, Freeform and Steep Concave Optics |
| M. Tricard (3), W.I. Kordonski, A.B. Shorey /C. Evans (1) |
| STC G, 55/1/2006, P.309 |
| Keywords: Finishing, Precision, Optical |
|
Abstract : Conformal, freeform and steep concave optics represent
important shapes that are difficult or impossible to finish using
conventional techniques due to mechanical interferences and steep local
slopes. One way to polish these optics is by using a jet of
abrasive/fluid mixture. Widely used abrasive water jet machining is not
applicable for precision polishing because of natural jet instability,
which gives an unstable removal function. Theoretical and experimental
results in this paper show how this problem can be addressed with a
magnetically stabilized jet of magnetorheological fluid. Polishing
results demonstrate the suitability for this technique for precision
finishing of complex shapes. |
| Defect-free Fabrication for Single Crystal Silicon Substrate by Chemo-Mechanical Grinding |
| L. Zhou, H. Eda, J. Shimizu, S. Kamiya, H. Iwase, S. Kimura /H. Sato (1) |
| STC G, 55/1/2006, P.313 |
| Keywords: Grinding, Silicon, Wafer |
|
Abstract : IIC chips are built on Si substrates which must have a high
degree of crystalline perfection. The single crystal Si ingot is first
sawn into wafers, each of which then undergoes lapping, etching and
several steps of polishing to remove the mechanical imperfection and to
achieve mirror surfaces. An alternative process has been newly developed
by effective use of solid-state reaction between the CeO2 abrasives and
Si. Si is removed in a form of amorphous Ce-O-Si at a dry condition. The
fabricated ?300 mm Si wafers are examined on both surface and
subsurface. The results show that 1) the surface is generated by fixed
abrasives following grinding dynamics, 2) no defect or mechanical
(structural) imperfection is introduced during fabrication and 3) far
better quality is achieved than that by CMP. |
| Ultra-thinning Processing of Dielectric Substrates by Precision Abrasive Machining |
| M. Touge, J. Watanabe /T. Matsuo (1) |
| STC G, 55/1/2006, P.317 |
| Keywords: Wafer, Lapping, Polishing |
|
Abstract : The ultra-thin dielectric substrate was obtained by precision
grinding and lapping/polishing. In the precision grinding, the substrate
was thinned until 50 ?m in thickness using fine-grained diamond wheels
and a polishing pad. The substrates in the lapping and polishing were
thinned to 17 ?m in thickness with good flatness. The good flatness was
produced by hard polishing pad made of polyvinyl chloride resin owing to
their mechanical properties of high fixed grain density. These were
confirmed by detailed AFM observations. Finally, the substrates were
segmentalized to produce five thousand small tips (2 mm X 0.4 mm) by a
precision dicing device. |
| Development of a High-Porosity Fixed-Abrasive Pad Utilizing Catalytic Effects of TiO2 on Polyurethane Matrix |
| T. Tateishi, Q. Gao, Y. Tani (2), K. Yanagihara, H. Sato (1) |
| STC G, 55/1/2006, P.321 |
| Keywords: Grinding, Tool Development, Aluminum |
|
Abstract : A new method of manufacturing a high-porosity fixed-abrasive
pad for grinding aluminum disks has been developed. In this development,
it was discovered that the addition of ultrafine TiO2 powders into
polyurethane during the polymerization process can induce foaming of the
polyurethane itself, which results in the highly porous structure of the
grinding pad. The utilization of this effect for manufacturing
fixed-abrasive pads make a porosity above 50%37; possible. The developed
high-porosity pad provides not only load-free grinding, but also a wide
selection of abrasive grains and a much finer surface roughness of 19.3
nm Rz compared with the polyvinyl alcohol (PVA) stone that is generally
used for grinding aluminum hard disk drive (HDD) substrates. |
| Multi-Sensor Monitoring System in Chemical Mechanical Planarization (CMP) for Correlations with Process Issues |
| H. Jeong, H. Kim, S. Lee, D. Dornfeld (1) |
| STC G, 55/1/2006, P.325 |
| Keywords: Monitoring, Sensor, CMP |
|
Abstract : In this paper, three different sensors were used to measure
multi-scale phenomena in chemical mechanical planarization. A
piezoelectric force sensor, Hall effect sensor and acoustic emission
sensor (AE) were installed in CMP equipment and the signals were
measured simultaneously during the polishing process. The results showed
that the sensors measuring frictional behaviour, such as the Hall effect
sensor and force transducer, produced a clear end point signal in the
case of the friction characteristics are distinguishable for each
material. Also, if there is difference in hardness between materials,
then a sharp end point signal is detected with the AE sensor even though
the friction characteristic is similar between the two materials.
Therefore, using multi-sensors having different bandwidths is
complementary for not only process monitoring but also end point detection. |
| Laser Dressing of Metal Bonded Diamond Wheel |
| A. Hosokawa, T. Ueda (2), T. Yunoki |
| STC G, 55/1/2006, P.329 |
| Keywords: Grinding, Laser, Dressing |
|
Abstract : In this study, a laser beam is used as a non-contact thermal
dressing tool for a bronze bonded diamond wheel. The pulsed-Nd:YAG laser
beam is irradiated on the wheel surface and the bond material partially
removed by laser irradiation only. In order to efficiently remove the
bond material, it is necessary to direct an air jet on the spot
irradiated by the laser so as to blow away the molten binder before it
solidifies again. Less damage of diamond particles such as micro-cracks
or graphitization occurs. In grinding with a laser-dressed wheel, the
grinding forces are almost the same as those for a conventionally
dressed wheel. Consequently, effective laser dressing can be expected
with the associated dressing conditions. |
| Speed Stroke Grinding of gamma-Titanium Aluminides |
| C. Zeppenfeld /F. Klocke (1) |
| STC G, 55/1/2006, P.333 |
| Keywords: Grinding, Titanium, Process Modelling |
|
Abstract : This paper describes the developments to implement the
innovative technology of speed stroke grinding for machining
gamma-titanium aluminides. These are difficult to cut materials with
high application potential in the aeronautic industry. In a first step,
a holistic process model is developed, which considers the tool wear and
the mechanical and thermal energy balances at high table speeds as well
as the crack formation mechanisms. In a second step, the theoretical
process model of speed stroke grinding is verified and extended by
experimental investigations. In addition to the analysis of the tool
wear mechanisms crucial points of the grinding investigations are the
analysis of the grinding temperatures and the structure of the workpiece
surfaces with special regard to crack and residual stress formation. |
| High Performance Cutting with Abrasive Waterjets beyond 400 MPa |
| A.M. Hoogstrate, T. Susuzlu, B. Karpuschewski (1) |
| STC G, 55/1/2006, P.339 |
| Keywords: Abrasion, Cutting, Waterjet |
|
Abstract : Abrasive waterjet (AWJ) cutting has been widely accepted by
the industry after the successful introduction of 400 MPa cutting
systems. This paper describes the cutting with AWJ beyond the current
industrial pressure limit. Firstly, the factors that limit the water
pressure are discussed. Secondly, the jet formation is considered by
addressing the effects of the geometry of the upstream tube and the
orifice. Finally, the AWJ cutting process is described in terms of
energy transfer efficiency. There is an optimum abrasive load ratio over
which the cutting ability of the jet decreases due to the less efficient
power transfer from waterjet to the abrasives. |
| Development of Environmentally Friendly Fluid for CBN Grinding |
| J.F.G. Oliveira (2), S.M. Alves |
| STC G, 55/1/2006, P.343 |
| Keywords: Grinding, Cubic boron nitride, Fluid |
|
Abstract : Environmentally friendly water based fluids have been offered
recently by many suppliers. On the other hand the G ratio values
obtained for CBN grinding with water based coolants are much lower than
with neat oil. This work presents a new water based grinding fluid
formulation able to meet both the performance and environmental
requirements for CBN grinding. The existence of a reaction between CBN
grains and water is evaluated in grinding tests and also in a chemical
reactor. The results show that the reaction between CBN grains and water
is not significant when compared to the measured volumetric wheel wear
in a grinding operation. Based on this fact, a new fluid concept
consisting of a high concentration (up to 40%37;) of sulfonate vegetable
oil in water is proposed and tested. In this way it was possible to
combine high lubricity, better heat conductivity and good environmental
properties in one fluid. The results show performance comparable to the
obtained with neat oil. |
| A High Material Removal Rate Grinding Process for the Production of Automotive Crankshafts |
| P. Comley (3), I. Walton, T. Jin, D.J. Stephenson (2) |
| STC G, 55/1/2006, P.347 |
| Keywords: Grinding, Surface Integrity, Thermal Modelling |
|
Abstract : In this paper the application of high efficiency deep grinding
to cylindrical plunge grinding is demonstrated and thermal modelling
used to optimise the grinding cycle for an automotive steel and cast
iron. The benefits associated with the high work speed achievable in
cylindrical grinding are highlighted and both thermal modelling and
experimental measurements have established that low workpiece
temperatures are possible even when specific material removal rates of
2000 mm3/mm.s are achieved. Surface integrity studies based on
microstructural analysis and Barkhausen noise have also demonstrated the
effectiveness of the process. |
| Precision, Stability and Productivity Increase in Throughfeed Centerless Grinding |
| I. Gallego (3), R. Lizarralde, D. Barrenetxea, P.J. Arrazola /R. Bueno (1) |
| STC G, 55/1/2006, P.351 |
| Keywords: Centerless grinding, Productivity, Simulation |
|
Abstract : Centerless grinding is a high precision manufacturing process
commonly applied to the mass production of many industrial components.
However, workpiece roundness is critically affected by geometric lobing
and no practical tool has been developed to solve the problem in
throughfeed working mode. Based on simulation methods previously applied
to plunge grinding, a new software tool has been developed in this work.
The software determines the optimal working configuration and can be
used to reduce set-up time and improve three important features: 1)
Precision, as the roundness error is rapidly corrected at the optimal
configuration. 2) Productivity, since the workpiece stock can be
significantly reduced. 3) Stability, because the process is less
sensitive to the original roundness error of the workpiece. |
| Grinding of Gears with Vitreous Bonded CBN-Worms |
| M. Reichstein, F. Catoni /L. Cronjaeger (1) |
| STC G, 55/1/2006, P.355 |
| Keywords: Grinding, Gear, Super abrasive |
|
Abstract : Among the industrial gear grinding processes, continuous
generating grinding allows the highest material removal rates due to its
kinematics. The process capabilities can be further increased by using
CBN as a more efficient abrasive material. The research work described
in this paper proves the high potential of vitreous bonded CBN grinding
worms. Compared to corundum worms, the CBN tools offer significantly
better behavior with regard to process stability, gear quality and
residual stress on the machined gear tooth flanks. The results also show
that a well adapted dressing technology is not only an important
prerequisite for the efficient application of CBN worms but it also
offers excellent and further possibilities to increase the grinding
process performance. Dressable CBN grinding worms have not yet been
introduced to industrial gear grinding processes. The paper gives an
insight into the preparation and application of these innovative tools
not only for academia but also for industry. |
STC M |
| Chatter Stability of Plunge Milling |
| Y. Altintas (1), J.H. Ko |
| STC M, 55/1/2006, P.361 |
| Keywords: Milling, Chatter, Stability |
|
Abstract : Plunge milling operations are used to remove excess material
in boring cylinders, roughing pockets, dies and mold cavities. This
paper presents a frequency domain, chatter stability prediction theory
for plunge milling. The regenerative chip thickness is modeled as a
function of lateral, axial and torsional vibrations. The stability of
the plunge milling is formulated as a fourth order eigenvalue problem by
relating the regenerative chip thickness, cutting forces and torque, and
the structural modes of the cutter. The stability lobes are predicted
analytically from the eigenvalue solution. The stability lobes are
experimentally proven by conducting over one hundred plunge milling tests. |
| Analysis of the Influence of Mill Helix Angle on Chatter Stability |
| M. Zatarain (2), J. Muñoa, G. Peigné, T. Insperger |
| STC M, 55/1/2006, P.365 |
| Keywords: End milling, Stability, Dynamics |
|
Abstract : Current methods for estimating chatter stability limits for
milling do not consider the influence of the helix angle and the
consequent phase lag between the forces appearing at different sections
of the mill. Budak and Altintas? multifrequency solution is extended to
include the helix effect, and results are compared with results of
semi-discretization and experiments. As a conclusion, the helix has an
important influence on the areas of added lobes (flip lobes), while the
influence on the traditional lobes is negligible. Flip lobes become
closed curves separated by horizontal lines where the depth of cut
equals a multiple of the helix pitch. |
| A Modelling Approach for Analysis and Improvement of Spindle-Holder-Tool Assembly Dynamics |
| E. Budak (2), A. Erturk, H.N. Ozguven |
| STC M, 55/1/2006, P.369 |
| Keywords: Milling, Structural Analysis, Chatter |
|
Abstract : The most important information required for chatter stability
analysis is the dynamics of the involved structures, i.e. the frequency
response functions (FRFs) which are usually determined experimentally.
In this study, the tool point FRF of a spindle-holder-tool assembly is
analytically determined by using the receptance coupling and structural
modification techniques. Timoshenko?s beam model is used for increased
accuracy. The spindle is also modeled analytically with elastic supports
representing the bearings. The mathematical model is used to determine
the effects of different parameters on the tool point FRF and to
identify contact dynamics from experimental measurements. The
applications of the model are demonstrated and the predictions are
verified experimentally. |
| A Fast, High-stiffness and High-resolution Piezoelectric Motor with Integrated Bearing and Driving Functionality |
| H. Van Brussel (1), W. Van de Vijver, M. De Volder, S. Devos, D. Reynaerts |
| STC M, 55/1/2006, P.373 |
| Keywords: Piezoelectric, Precision, Positioning |
|
Abstract : With growing requirements on the precision of production
machines, as expressed by the Taniguchi curves, the need arises for
novel actuators that are able to combine high stiffness and high
position resolution with high drive speeds. In this paper two novel
integrated linear actuation systems with high active stiffness and with
the unique ability to provide simultaneously high-resolution slow motion
and lower-resolution high-speed motion, based on piezotechnology, are
presented. Potential applications are stages for novel high-precision
abrasive machining (e.g. ultraprecision grinding), lithography (e.g.
extreme-UV wafer steppers), positioning devices working in vacuum (e.g.
scanning electron microscopy). |
| A Micro-positioning Parallel Mechanism Platform with 100-degree Tilting Capability |
| D.S. Kang, T.W. Seo, Y.H. Yoon, B.S. Shin, X.-J. Liu, J. Kim (2) |
| STC M, 55/1/2006, P.377 |
| Keywords: Parallel mechanism, Kinematic analysis, Micromanipulator |
|
Abstract : This paper presents a micro-positioning platform based on the
unique parallel mechanism recently developed by the authors. The
platform has a meso-scale rectangular shape whose size is 20 x 23 mm.
The stroke is 5 mm for both the x- and y-axis and 100 degrees for the
?-axis (the rotational axis along the x-axis). The platform is actuated
by the three sets of two-stage linear actuators: a linear motor for
rough positioning and a piezo actuator for fine positioning. The
platform is already assembled. The detailed design issues, including the
kinematic analysis, and the experimental results of the positioning
measurements and control performance, are presented. |
| Development of 5-Axis Linear Motor Driven Super-Precision Machine |
| P. Sriyotha, K. Nakamoto, M. Sugai, K. Yamazaki (1) |
| STC M, 55/1/2006, P.381 |
| Keywords: Ultra-precision, Nano technology, Linear drive |
|
Abstract : Recent strong demand for production of ultra-precision
components drives the need for 5-axis super-precision machines. A design
study of such a 5-axis super-precision machine, which is capable of
nanometer-level precision cutting, has been conducted by searching
innovative solutions to the three major problems: friction, thermal
deformation, and positioning accuracy. The final design implemented the
following: stiff aerostatic guideways for near frictionless motion while
structural rigidity was maintained, thermally stable structures made of
alumina ceramics, and smooth control of linear motor based actuation
system by employing high resolution and highly responsive linear
encoders and linear power amplifiers. The designed machine has been
built to verify the targeted performance. Various shapes that require
nanometer- accuracy have been created using the machine. The results
have consistently indicated stable nanometer-level accuracy. Targeted
design performance has been successfully demonstrated. |
| Development of Ultrasonic Vibration Assisted Polishing Machine for Micro Aspheric Die and Mold |
| H. Suzuki, T. Moriwaki (1), T. Okino, Y. Ando |
| STC M, 55/1/2006, P.385 |
| Keywords: Polishing, Ultrasonic, Mold/Die |
|
Abstract : Demands are increasing for micro axis-symmetric aspherical
lenses to be installed in various optical devices. The micro glass
lenses are generally molded by glass press process with micro aspheric
ceramic molding dies or molds made of tungsten carbide or silicon
carbide. These dies and molds are mostly ground with micro diamond
wheels, but require additional finishing process as the size of the dies
and molds become smaller and the required accuracy becomes higher. In
order to finish micro aspheric dies and molds with diameter less than
3mm, an ultrasonic vibration assisted polishing machine is developed. A
small polishing tool is mounted on a 3-axis controlled table, and
vibrated at an ultrasonic frequency with piezo-electric actuators. The
polishing pressure can be controlled with a resolution of 2 mN. Some
micro aspheric molding dies made of binder-less tungsten carbide were
polished, and the form accuracy below 70 nmP-V and surface roughness of
7 nmRy were obtained with the developed machine. |
| Hierarchical Predictive Control within an Open Architecture Virtual Machine Tool |
| M. Susanu, D. Dumur (1) |
| STC M, 55/1/2006, P.389 |
| Keywords: Control, Virtual Machine tool, Open Architecture |
|
Abstract : The proposed hierarchical structure, based on the a priori
knowledge of the toolpath and using the receding horizon principle, aims
at reducing the degradation of tracking performances due to control
signals saturation. Starting with the predictive feed drives control as
first level, a second one, called trajectory supervisor, modifies in a
predictive way as well the axial setpoints in order to minimize the
impact of control signals saturation on the tracking accuracy. The third
level, called trajectory regenerator, acts with an anticipative effect
when the modified setpoints are too distant from the original ones and
recomputes the entire toolpath. This strategy is further tested within
an open architecture virtual machine tool. |
| High Bandwidth Control of Ball Screw Drives |
| K. Erkorkmaz (2), A. Kamalzadeh |
| STC M, 55/1/2006, P.393 |
| Keywords: Feed, Drive, Control |
|
Abstract : This paper presents a tracking control strategy for high speed
ball screw drives. Rigid body motion is controlled using adaptive
sliding mode control. Torsional vibrations are modeled, experimentally
identified, and compensated in the control law using notch filtering and
active cancellation techniques. Attenuation of torsional resonances
improves the stability margins and enables high positioning bandwidth to
be achieved. The axis friction is experimentally identified and
cancelled out in feedforward, in order to improve the positioning
accuracy at motion reversals. The developed control law is verified
experimentally on a high speed ball screw drive, where a tracking
accuracy of 1.6 um is maintained while traversing the axis at 1000
mm/sec feed and 1 g acceleration. |
| Virtual Computer Numerical Control System |
| K. Erkorkmaz (2), Y. Altintas (1), C.-H. Yeung |
| STC M, 55/1/2006, P.399 |
| Keywords: Virtual, Simulation, Computer Numerical Control (CNC) |
|
Abstract : This paper presents a comprehensive virtual simulation model
for CNC systems. The Virtual CNC (VCNC) has a modular architecture,
allowing a real CNC to be prototyped quickly from standard library
functions for feed drive models, feedback devices, axis control laws,
and trajectory interpolation. Additional CNC modules can easily be
prototyped and integrated to the VCNC by the user. Various application
examples are presented which include the prediction of contour errors,
auto-tuning of feed drive controllers, toolpath and feed modification
for improved cornering, and rapid identification of closed loop drive
dynamics. Detailed experimental verification is presented for each
algorithm. |
| Method for the Optimization of Kinematic and Dynamic Properties |
| R. Neugebauer (1), W.-G. Drossel (3), C. Harzbecker (3), S. Ihlenfeldt, S. Hensel |
| STC M, 55/1/2006, P.403 |
| Keywords: Optimization, Kinematic, Dynamic |
|
Abstract : The paper introduces an approach, which allows the
consideration of the kinematic as well as the dynamic properties of
parallel kinematic machines. Based on the results of a preceding
kinematic optimization, a FEM-model with arbitrary input parameters is
designed. The full kinematic functionality of struts and joints used is
ensured. By coupling the FEM-model to the GNU Octave numerical program
system, a variety of movements including machining forces can be
simulated. A Broyden-Fletcher-Goldfarb-Shanno optimization algorithm,
using GNU Octave, was written and coupled to the FEM-system. Now, this
algorithm is able to influence the model?s arbitrary input parameters
during the optimization process. Thus, the model is optimized
automatically for a certain machining process and/or dynamic behavior.
This procedure is demonstrated using the example of a delta robot
structure originally designed by Raymond Clavel [7]. |
| Force Free Add-on Position Measurement Device for the TCP of Parallel Kinematic Manipulators |
| A. Verl, N. Croon, C. Kramer, T. Garber /G. Pritschow (1) |
| STC M, 55/1/2006, P.407 |
| Keywords: Parallel Kinematic Manipulator, Accuracy Improvement, Measurement Device |
|
Abstract : The position of the tool center point (TCP) of a parallel
kinematic manipulator (PKM) is traditionally being measured indirectly
by means of the position measurement of the drives. Cutting forces and
acceleration forces cause displacements of the TCP, which cannot be
detected from the position measurement of the drives. To improve the
position accuracy of the TCP a force free add-on position measurement
device is suggested. The kinematic design of such a measurement device,
the calibration and its application for feedback control and improved
TCP positioning in the presence of external forces is described.
Experimental results are presented to illustrate the expected
improvements in TCP positioning. |
| A New Fluid Bearing Utilizing Traveling Waves |
| E. Shamoto (2), N. Suzuki, A. Hamaguchi |
| STC M, 55/1/2006, P.411 |
| Keywords: Bearing, Actuator, Wave |
|
Abstract : A new non-contact fluid bearing, which utilizes traveling
waves, is proposed in the present research. The moving part is supported
with a thin fluid film compressed by the waves traveling radially on the
bearing surface. Conventional hydrostatic bearings utilize externally
compressed fluid, which requires plumbing and compressors. On the other
hand, the proposed bearing realizes non-contact smooth motion without
such a large apparatus, and furthermore it has a capability to
electrically control the bearing force or clearance. A prototype air
bearing is developed on the basis of the proposed principle by utilizing
piezo-electric actuators, and its non-contact smooth motion is confirmed. |
| High Precision Positioning with Ferrofluids as an Active Medium |
| E. Uhlmann (2), N. Bayat |
| STC M, 55/1/2006, P.415 |
| Keywords: Positioning, Precision, Ferrofluid |
|
Abstract : Ferrofluids are magnetically controllable fluids which can be
used as an active medium in high precision positioning systems. The
capability of ferrofluids for being fixed with an applied external
magnetic field and their magnetorheological behavior are main properties
for technical applications. Beside that, amplifying the magnetic force
acting on the surface of a paramagnetic actor which levitates in a
ferrofluid can be used for the high precision positioning of objects. In
this paper different types of magnetofluidic positioning systems are
described and the influences on the velocity of positioning and on the
accuracy of positioning are discussed. |
| Numerical and Experimental Analysis for the Small Vibration of Aerostatic Guideways |
| T. Aoyama (2), Y. Kakinuma, Y. Kobayashi |
| STC M, 55/1/2006, P.419 |
| Keywords: Bearing, Design, Vibration |
|
Abstract : Aerostatic guideways have been used in many fields and are
absolutely essential for ultraprecision machining . Recently, with
increasing demand for ultraprecision devices, the accuracy of 1nm or
less has become necessary. On the other hand, conventional aerostatic
guideways are not designed considering the influence of small vibration
which occurs by supplying air. This vibration is hampering the
improvement in accuracy. In this study, a new design of the outlet of
orifice restrictors is proposed from the result of numerical analysis
and its effect is examined numerically and experimentally. The mechanism
for the occurrence of small vibration is analyzed and the methods to
suppress the small vibration are proposed. |
| Thermography-Based Investigation into Thermally Induced Positioning Errors of Feed Drives By Example of a Ball Screw |
| U. Heisel (1), G. Koscsák, T. Stehle |
| STC M, 55/1/2006, P.423 |
| Keywords: Temperature, Deformation, Thermography |
|
Abstract : The following paper presents a method, based on thermographic
measurements, to calculate the thermally induced positioning errors of
feed drives in machine tools, here described with the example of a ball
screw drive. Especially the effect of an uneven temperature distribution
in the components on the total deformation is examined in this method. A
transformation between the 3-D object space and the 2-D image space was
created by means of digital image processing and photogrammetry as well
as defined reference points on the structure of the feed drive with the
surrounding machine components. The transformation enables the necessary
identification of the defined structure points in the thermographic
picture. With the help of the temperature information contained in the
thermographic images, the respective thermally induced errors can then
be calculated depending on the respective axial position by means of a
temperature deformation model. |
| Damage Monitoring of Ball Bearing |
| T. Hoshi (1) |
| STC M, 55/1/2006, P.427 |
| Keywords: Spindle, Bearing, Damage Monitoring |
|
Abstract : A simple method and low cost equipment have been developed for
monitoring the damage that occurs on rolling surfaces of the ball
bearing in machine tool spindle. The monitoring identifies the
initiation and the progress of geometrical damage of bearing surfaces
and issues a warning prior to the end of bearing life. |
STC O |
| Measuring Flexibility in Investment Decisions for Manufacturing Systems |
| E. Abele (2), T. Liebeck, A. Wörn |
| STC O, 55/1/2006, P.433 |
| Keywords: Manufacturing System, Flexibility, Decision Making |
|
Abstract : Today?s international competitive and fast changing
environment forces manufacturing companies to consider their reactivity
and flexibility in investment decisions. Especially modern manufacturing
systems such as FMS and RMS offer manifold possibilities to adapt to new
requirements. However, because of the difficulty to measure and
synchronize the requirements and potentials of flexible solutions,
dynamically cost efficient solutions are still rare in practice.The
approach described in this paper provides a pragmatic solution to
integrate a Real Options Analysis into the classical Net Present Value
approach in order to give a holistic evaluation of investments.
Especially industries undergoing fast changes in production technology
can realize substantial competitive advantages through a continuous
adaptation to state of the art production techniques. The RMS represents
a favorable concept to enable update capabilities. |
| Effect of Time-Based Parameters on the Agility of a Dynamic MPC System |
| A.M. Deif, W.H. ElMaraghy (1) |
| STC O, 55/1/2006, P.437 |
| Keywords: Manufacturing Planning and Control |
|
Abstract : This paper presents a dynamic manufacturing planning and
control (MPC) system that can maintain agility through the ability to
dynamically switch between different policies due to varying market
strategies. The dynamic behavior of the developed system is investigated
by studying the effect of the time based parameters on responsiveness
and cost effectiveness of the system reflected in the natural frequency
and the damping of its different configurations. Results showed that the
agility requirements are directly affected by the time based parameters
of the MPC system: production lead time, capacity scalability delay, and
shipment time. This resulted in a better understanding of the
requirements for a well designed agile MPC system. |
| Logistic Production Operating Curves ? Basic Model of the Theory of Logistic Operating Curves |
| P. Nyhuis /H.-P. Wiendahl (1) |
| STC O, 55/1/2006, P.441 |
| Keywords: Optimisation, Production, Management |
|
Abstract : One key task of production logistics is the positioning of
work systems in the field of conflict between the logistic performance
measures throughput time, work in progress (WIP) level, machine
utilisation and schedule reliability. The interdependencies of these
logistic performance measures can be simulated by the Logistic
Production Operating Curves in qualitative and quantitative terms. These
curves therefore enable the logistical positioning of work systems.
Starting with the derivation and the validation of the mathematical
description of the Logistic Production Operating Curves for individual
work systems, the paper introduces further Logistic Operating Curves for
describing logistic parameters. |
| Availability Assessment of Multi-State Manufacturing Systems Using Universal Generating Function |
| A.M.A. Youssef, A. Mohib, H.A. ElMaraghy (1) |
| STC O, 55/1/2006, P.445 |
| Keywords: Manufacturing System, Performance, Availability |
|
Abstract : The ability of a manufacturing system configuration to satisfy
production demands depends on its availability. The use of the Universal
Generating Function (UGF) for evaluating the availability of multi-state
manufacturing systems capable of producing multiple-parts is proposed. A
generalization of the UGF is introduced in order to deal with multiple
types of output performance. This allows considering multiple production
rates corresponding to the different parts produced by the manufacturing
system. A case study is presented to illustrate the use of the
generalized UGF technique in assessing and comparing manufacturing
system configurations based on availability. |
| Performance of Coupled Closed-Loop Workstation Capacity Controls in a Multi-Workstation Production System |
| J.-H. Kim, N.A. Duffie (1) |
| STC O, 55/1/2006, P.449 |
| Keywords: Production, Control, Analysis |
|
Abstract : In this paper, a dynamic model is developed for
multi-workstation production systems in which closed-loop capacity
controls for regulating WIP in individual workstations are coupled by
adding predictive control, making capacity adjustments a combination of
compensation for local disturbances and anticipation of downstream
effects of capacity adjustments made upstream in the system. The added
coupling at the control level combined with intrinsic coupling at the
order-flow level effectively integrates planning and control, but
increases system complexity. Control-theoretic methods are used to make
dynamic analysis tractable and improve understanding of dynamic
behaviour, which is illustrated using data from an industrial production
system. |
| Impact of Quality Control on Production System Performance |
| M. Colledani, T. Tolio (2) |
| STC O, 55/1/2006, P.453 |
| Keywords: Performance Evaluation, Quality Control, Production Logistics |
|
Abstract : Quality and production logistics have been traditionally
considered as separate fields, both by researchers and industrialists.
However, during the design phase of production systems, the decisions
taken as an answer to productivity requirements have an impact on
product quality; similarly the decisions taken to meet quality
requirements affect the productivity performance of the system. The
paper proposes an approach to evaluate the overall performance of the
system considering both quality and production logistics. The results
obtained by the application of the method provide new insight in the
relations among the two areas and pave the way to the joint design of
production logistics and quality control systems. |
| Human Factors in the Management of Production |
| P.L. Jensen, L. Alting (1) |
| STC O, 55/1/2006, P.457 |
| Keywords: Production, Management, Human factor |
|
Abstract : The ?Human factor? is a major issue when optimizing
manufacturing systems. The development in recommendations on how to
handle this factor in the management of production reflects the change
in dominating challenges faced by production in society. Presently,
industrial societies are meeting new challenges. Qualitative interviews
with Danish stakeholders in the education of engineers (BA & MA) confirm
the picture given in international literature. Therefore, the didactics
concerning the ?human factor? in the curriculum on production management
has to reflect these changes. This paper concludes with a proposal on
essential issues to be addressed in the curriculum qualifying university
candidates to production management. |
| A Concept for Knowledge Transfer between new Product Projects in the Automotive Industry |
| J. Uffmann, W. Sihn (2) /H.-J. Warnecke (1) |
| STC O, 55/1/2006, P.461 |
| Keywords: Knowledge, Developement, New Product Project |
|
Abstract : Global mergers and acquisitions in the automotive industry
have left only a few companies offering a variety of brands. Shorter
product life cycles have increased the number of product launches for
each brand, raising the number of new product projects for companies in
the automotive sector. In a new vehicle project, covering all product
creation stages, the knowledge about product and production process
gained by vehicle and production tests increases as the new product
project approaches the start of production. The approach in this paper
focuses on potential changes to product and production process that do
not go through the change management process. These potential changes
can be exploited in current or subsequent projects. |
| A New Approach to the Optimisation of Blends Composition in Injection Moulding of Recycled Polymers |
| G. Lucchetta, P.F. Bariani (1), W.A. Knight (1) |
| STC O, 55/1/2006, P.465 |
| Keywords: Injection Moulding, Polymer, Rheological Model |
|
Abstract : The use of recycled polymers is widespread for the injection
moulding of many commodity plastic parts. Recycled polymers are usually
blended with virgin polymers to obtain the best trade-off between cost
and low melt viscosity. This last constraint is necessary to avoid short
shots and to minimize the clamp force of therequired injection moulding
machine and, therefore, the process cost. The current industrial
approach to this problem is to select the polymer blend by trial and
error. In this paper a new approach to the minimisation of the overall
manufacturing cost is proposed. It is based on a rheological model of
the blend which has been developed from experimental tests according to
the mixture design technique. The approach has been validated through an
industrial case study. |
| Modeling Biological Manufacturing Systems with Bounded-Rational Agents |
| K. Ueda (1), T. Kito, N. Fujii |
| STC O, 55/1/2006, P.469 |
| Keywords: Manufacturing system, Emergent synthesis, Bounded rationality |
|
Abstract : This paper presents bounded rationality as a characteristic of
agents to develop their behavior in Biological Manufacturing Systems
(BMS) that can deal with the complexity of the manufacturing environment
using the ideas of self-organization, evolution and learning. Clarifying
the definition and description of bounded rationality, the approach is
implemented in an Ant System model. The purpose of the model is to
handle the uncertainty in the perception, action and inner structure of
agents by introducing bounded rationality in their characteristics.
Computer simulation demonstrates the effectiveness of the approach by
indicating significant improvement in the performance of the modeled BMS. |
| Stochastic Dynamic Production Control by Neurodynamic Programming |
| L. Monostori (1), B.Cs. Csáji |
| STC O, 55/1/2006, P.473 |
| Keywords: Production control, Machine learning, Neurodynamic programming |
|
Abstract : The paper proposes Markov Decision Processes (MDPs) to model
production control systems that work inuncertain and changing
environments. In an MDP finding an optimal control policy can be traced
back tocomputing the optimal value function, which is the unique
solution of the Bellman equation. Reinforcementlearning methods, such as
Q-learning, can be used for estimating this function; however, the value
estimationsare often only available for a few states of the environment,
typically generated by simulation. Thepaper suggests the application of
a new type of support vector regression model, called ?-SVR, which
caneffectively fit a smooth function to the available data and allow
good generalization properties. The effectivenessof the approach is
shown by experimental results on both benchmark and industry related
data.The paper proposes Markov Decision Processes (MDPs) to model
production control systems that work inuncertain and changing
environments. In an MDP finding an optimal control policy can be traced
back tocomputing the optimal value function, which is the unique
solution of the Bellman equation. Reinforcementlearning methods, such as
Q-learning, can be used for estimating this function; however, the value
estimationsare often only available for a few states of the environment,
typically generated by simulation. Thepaper suggests the application of
a new type of support vector regression model, called ?-SVR, which
caneffectively fit a smooth function to the available data and allow
good generalization properties. The effectivenessof the approach is
shown by experimental results on both benchmark and industry related data. |
| Systematic Analysis of PPC System Deficiencies ? Analytical Approach and Consequences for PPC Design |
| H.-H. Wiendahl /E. Westkämper (1) |
| STC O, 55/1/2006, P.479 |
| Keywords: Optimization, Production, PPC model |
|
Abstract : Manufacturing companies often complain about the difficulties
in meeting customers' logistic requirements. Many blame the production
planning and control (PPC) software for the perceived performance
deficiencies. This paper illustrates why this only accounts for part of
the problem: a holistic PPC configuration includes the six aspects of
targets, functions, objects, processes, positions and tools. Based on
the requirements for an ideal PPC configuration, the paper identifies a
list of typical stumbling blocks. Analyzing them from the perspectives
of the individual aspects will explain the deficiencies and indicate
possible solutions. Finally the paper describes a procedure for
identifying stumbling blocks in practice and how to overcome them. |
| A Theoretical Framework for the Integration of Resource Aware Planning with Logistics for the Dynamic Validation of Aggregate Plans within a Production Network |
| P.G. Maropoulos (1), A. Kotsialos, D.G. Bramall |
| STC O, 55/1/2006, P.483 |
| Keywords: Planning, Logistics, Optimisation |
|
Abstract : One of the most persistent and potentially far reaching, in
terms of industrial benefits, problem in new product development, is the
parallel and synchronous design and evaluation of the product, the
production processes and the production network. The proposed
theoretical framework for collaborative design and production network
development is based on the concept of Digital Enterprise Technology
(DET) and facilitates the integration of design and resource aware
planning with aspects of network design and logistics. The controlling
cycle of the framework is the DET-enabled, human centric evaluation of
products, plans and network configurations that gives rise to an
emergent synthesis environment. Early testing using aerospace products
has been very encouraging. |
| Coordinating Supply Networks in Customized Mass Production ? A Contract-Based Approach |
| J. Váncza (2), P. Egri |
| STC O, 55/1/2006, P.489 |
| Keywords: Production, Co-operative, Planning |
|
Abstract : In the paper we discuss conflicting performance requirements
in customized mass production and suggest a novel cooperative planning
method for sharing information and coordinating decisions between a
focal manufacturer and its suppliers. The method strives to achieve high
service level and minimal expected average costs?including production,
inventory and potential obsolete inventory costs. A channel coordination
mechanism drives the overall system towards its right behavior even
though the partners make planning and scheduling decisions autonomously.
We present the mechanism and discuss its properties on simulated test
cases taken from an industrial case study. |
| Planning and Scheduling System for Make-To-Order Production |
| V. Toivonen, K. Ikkala, E. Niemi /A. Korhonen (1) |
| STC O, 55/1/2006, P.493 |
| Keywords: Optimisation, Planning, Scheduling |
|
Abstract : A system for the planning of make-to-order production in the
mechanical engineering industry is described. In the present system, a
multiple-phase heuristic procedure is used to schedule the orders.
Various objectives are used; amongst others are resource profile peak
minimization and the minimization of the sum of the squares of the total
resource usages during each time period and over all resources. The
activity intensities are taken to be variable and are adjusted in order
to achieve smooth resource profiles. The performance of the system is
found to be good with respect to large practical problems. |
| Methodology for Dimensioning Technological Interfaces of Manufacturing Process Chains |
| B. Denkena (2), H. Rudzio, A. Brandes |
| STC O, 55/1/2006, P.497 |
| Keywords: Computer aided planning, Flexibility, Cost |
|
Abstract : The paper introduces a methodology for process chain planning
that is based on the optimisation of technological interfaces and uses
multi-criteria optimisation techniques. The manufacturing of helical
car-gearings including precision forging technology was investigated as
a reference for validation. An employment of modern materials and
technologies is often not sufficient for an optimisation of entire
process chains. In the future, technological and computational
integration of alternative production technologies will be decisive for
long-term success. This integration can be seen as an important step
towards sustainable process chain optimisation. Having this in mind, the
positioning of technological interfaces has been addressed by scientists
at Hannover University. |
| Staged Postponement of Order Specification Commitment for Supply Chain Management |
| Q.L. Zeng, M.M. Tseng (1), R.F. Lu |
| STC O, 55/1/2006, P.501 |
| Keywords: Optimisation, Planning, Staged Postponement |
|
Abstract : Postponement of order commitment, particularly product
differentiation, has been generally accepted as an effective measure in
supply chain management. With the volatile market fluctuation and rapid
changes in product technology, the timing for committing product
specifications becomes very important to buyers and producers alike in
improving the overall supply chain efficiency. This paper reports
research results in developing a systematic approach to decide the
selection of product attributes and timing of staged commitment to
improve responses to customer requirements. The approach starts with
categorizing attributes and aggregation of processes to reduce the
complexity. A mathematical model incorporating capacity, interlocking
and sequential constraints are built to identify the optimal commitment
schema. An industrial case is prepared to illustrate the research result. |
| Sm@rt Logistics: Intelligent Networked Systems |
| G. Schuh (2) |
| STC O, 55/1/2006, P.505 |
| Keywords: Flexibility, Agent, Logistics |
|
Abstract : Inbound logistics is even in mass production often
characterized by a growing number of product variants and the trend
towards ?lot size one?. In comparison with classic demand-oriented
supply principles and Kanban, an event driven planning and control
system based on negotiation mechanisms leads to more efficient and
secure logistics processes. Therefore three solutions have been
developed. To acquire the needed real time information, RFID-tags are
used and an electronic assistance system is developed. Second, different
levels of information processing provide a dynamic and flexible planning
module and a process controlling with plausibility checks. Third, a
robust sensing infrastructure on the shop floor can be ensured despite
interferences like electromagnetic fields. |
| High Level Planning of Reconfigurable Enterprises: a Game Theoretic Approach |
| P. Argoneto, M. Bruccoleri, G. Lo Nigro, G. Perrone (2), S. Noto La Diega (1), P. Renna |
| STC O, 55/1/2006, P.509 |
| Keywords: Computer aided planning, Distributed manufacturing, Multi-agent system |
|
Abstract : Reconfigurable Enterprises (REs) represent production networks
made of different and geographically dispersed plants that, in case of
unpredictable market changes, can be reconfigured in order to gather a
specific production objective. However, REs effectiveness and efficiency
depend on the extent to which global performance is obtained. Basically
two approaches are available to reach coordination: centralised or
decentralised planning tools. In this paper, the authors propose a novel
cooperative game theoretical approach for distributed production
planning at high level of a RE; the proposed approach has been
benchmarked in front of both a distributed one, based on negotiation,
and a centralized one. |
| Virtual Enterprise Coalition Strategy with Game Theoretic Multi-Agent Paradigm |
| T. Kaihara, S. Fujii /K. Iwata (1) |
| STC O, 55/1/2006, P.513 |
| Keywords: Coordination, Agent, Decision making |
|
Abstract : Nowadays, Virtual Enterprise (VE) is a crucial paradigm of
business management in agile environment. VE exists in several kinds of
organizations, although the complexity of the each enterprise in VE may
vary greatly. Clearly, there is a need for a mechanism through which
these different enterprises can be integrated together. In this paper,
we focus on negotiation process in VE formulation as a basic research to
clarify its effective management. Each enterprise in VE is defined as
software agent with multi-utilities and a framework of multi-agent
programming with game theoretic approach is proposed as negotiation
algorithm amongst the agents. We develop a computer simulation model to
form VE through multiple negotiations amongst several potential
partners, and finally clarify the formulation dynamism with the proposed
negotiation process. |
| Design Method and Software Architecture for Federal SME Production Networks |
| H. Meier (2), M. Golembiewski, C.S. Zoller |
| STC O, 55/1/2006, P.517 |
| Keywords: Optimization, Process Management, Supply Chain Management |
|
Abstract : The article describes general characteristics of small and
medium-sized production networks. On the basis of the diversification of
these, the small and medium-sized enterprises can define their network
strategy for the production network. In order to transfer the network
strategy into reality, however, a structured method for the modeling of
the small and medium-sized enterprise network processes is required. The
article introduces this method for the design and optimization of a
federal small and medium-sized enterprise production network. Finally,
the federal characteristics of SMEs and the designed production network
processes leads to new software architecture. |
| Autonomous Work Systems in Manufacturing Networks |
| P. Butala, A. Sluga (2) |
| STC O, 55/1/2006, P.521 |
| Keywords: Distributed manufacturing, Work system, Structure |
|
Abstract : Manufacturing networks open new possibilities and potentials
in design, development and production of complex high-tech products
while they combine good characteristics of large companies with
advantages of SMEs. In order to manage the structural complexity of a
manufacturing network, the paper proposes the business-to-manufacturing
network B2MN approach based on the market mechanism. Next, the network
nodes in terms of the autonomous work system (AWS) are conceptualized.
AWS encapsulates functionalities and competencies related to its
management and manufacturing operations, as well as its autonomous
information system, which supports autonomous decision-making and
cooperation in the network. The case study illustrates the
implementation of the AWS concept in industry. |
STC P |
| Complete 3-D Self-calibration of Coordinate Measuring Machines |
| Q.C. Dang, S. Yoo, S.-W. Kim (2) |
| STC P, 55/1/2006, P.527 |
| Keywords: CMM, Calibration, 3-D self-calibration |
|
Abstract : Self-calibration allows testing machine motion errors without
being affected by the precision of calibration artifacts, but its
implementation has been limited to 1-D and 2-D domains due to lack of
suitable 3-D methodology. We present in this paper an extended algorithm
that provides a complete 3-D solution of self-calibration especially for
testing coordinate measuring machines. Using a 3-D grid artifact of
steel balls, four separate data sets of measurements are taken with
different views of the artifact. Then parasitic errors related to the
artifact are identified through algebraic manipulation, so that a
complete 3-D map of machine systematic errors is constructed.
Experimental results validate the proposed algorithm by confirming that
the calibration accuracy is limited only by the measurement
repeatability of the CMM under test. |
| Model-based ?Chase-the-Ball? Calibration of a 5-Axes Machining Center |
| B. Bringmann, W. Knapp (1) |
| STC P, 55/1/2006, P.531 |
| Keywords: Calibration, Simulation, Uncertainty |
|
Abstract : A procedure for model-based calibrating 5-axes machining
centers is presented. Machine errors cause relative TCP deviations
between a sphere and probing system that can be measured in X, Y and Z
simultaneously during a five axes measurement cycle. The exact kinematic
configuration of the machine tool can be identified by numerically
reproducing the errors that would cause deviations closest to the ones
measured. The measuring device, the machine model and the measurement
procedure are described briefly. A method well known in robotics is
applied to evaluate the mathematical stability of the error
identification. With it a suitable number and location of measuring
poses and a suitable model setup can be determined. A new general Monte
Carlo approach using a full machine error model is applied to determine
the expected overall geometric behavior of the machine tool after the
calibration. With it uncertainty estimations can be made for any
calibration approach. Finally, measurement results before and after the
calibration are shown. |
| Uncertainty in Testing the Metrological Performances of Coordinate Measuring Machines |
| E. Savio (2) |
| STC P, 55/1/2006, P.535 |
| Keywords: Coordinate measuring machine, Test, Uncertainty |
|
Abstract : Performance verification of Coordinate Measuring Machines
(CMMs) is a key task in quality assurance systems. Test results are
influenced by various error sources that affect the test with their
uncertainty contribution, therefore the correct identification and
quantification of these error sources is a crucial task for a proper
estimation of the test uncertainty. The paper discusses the
identification of the uncertainty contributions to be taken into account
for the estimation of the test uncertainty in connection to three tests
for the verification of important CMM subsystems: i) rotary table test;
ii) contact scanning probe test; iii) video probe test. |
| Evaluation of Runout Deviation at Bevel Gears based on Pitch Measurements |
| A. Guenther /R. Hocken (1) |
| STC P, 55/1/2006, P.539 |
| Keywords: CMM, Bevel gear inspection, Runout evaluation |
|
Abstract : The ever-increasing number of manufactured gears requires,
among other things, shorter quality inspectiontimes. With the
introduction of coordinate measuring machines (CMM), the importance of
classic measuringmethods for bevel gears decreased more and more [1].
The classic direct runout measurement is a functionoriented, over-all
inspection of a bevel gear. Its result is one of the criteria to
classify gears in standardisedaccuracy grades (former quality groups).
Instead, modern bevel gear inspections with CMMs only measurethe pitch
deviations on both flanks and subsequently estimate runout deviation
based on explicitly lessinformation than the classical (direct) runout
measurement. This paper presents a new approach for thisevaluation
problem and compares theoretical and experimental runout results carried
out with severalCMMs. |
| Manufacturing and Measurement of the MIRI Spectrometer Optics |
| P. Shore, p. Morantz, D. Lee /P.A. McKeown (1) |
| STC P, 55/1/2006, P.543 |
| Keywords: Ultra-precision, Diamond turning, Measurement |
|
Abstract : The Mid-Infrared Instrument (MIRI) on the JWST, Hubble space
telescope replacement, contains an integral field spectrometer utilising
four integral field units (IFU). This paper introduces manufacturing and
measurement techniques developed to produce the monolithic multi-mirror
arrays which perform spatial splitting and reformatting of light within
each IFU: the image slicers and re-imagers. Typical slicer components
have 18-22 mirrors of 50 nm RMS form accuracy, 5 nm Rq roughness and
relative spatial positioning between mirror facets to 20 µm. The paper
provides data for the Verification Model slicers produced by Cranfield
University for the JWST MIRI consortium. |
| NURBS Based Ultra-Precision Free-Form Machining |
| C. Brecher, S. Lange, M. Merz, F. Niehaus, C. Wenzel, M. Winterschladen /M. Weck (1) |
| STC P, 55/1/2006, P.547 |
| Keywords: Machining, Precision, Control |
|
Abstract : The machining of ultra-precision optical components with form
tolerances in the sub-micron range requires a close interaction between
the machine tool, the process and the procedure for the NC tool path
generation. Especially for the optical free-form machining the choice of
a data-format for the surface description as well as the calculation of
the tool path is crucial for the overall achievable quality of the work
piece. This paper pre-sents the layout of a tool path calculation based
on the NURBS data format that has been developed at the Fraunhofer IPT.
In addition the interfaces and the hardware and software for the
realisation of a NURBS based control unit for Fast Tool Servo turning
and local corrective polishing operations are described. |
| Ultra-Precision Diamond Cutting of Steel Molds |
| E. Brinksmeier (1), R. Gläbe, J. Osmer |
| STC P, 55/1/2006, P.551 |
| Keywords: Ultra-Precision Machining, Steel, Tool Wear |
|
Abstract : Excessive chemical tool wear occurs when steel alloys are
machined with monocrystalline diamond tools. The basic idea of the
presented research work is to avoid chemical reactions between the
carbon of the diamond tool and the iron of the workpiece by establishing
a chemical bond between the iron and another chemical element. Therefore
a thermo-chemical process for modifying the chemical composition of the
subsurface zone was developed. As a result the diamond tool wear was
reduced by more than three orders of magnitude which by no other method
has been achieved so far. The surface roughness obtained in diamond
cutting of carbon steel was better than 10 nm Ra. |
| Development of a double sided Stitching Interferometer for Wafer Characterization |
| M. Jansen, p. Schellekens (1) , H. Haitjema (2) |
| STC P, 55/1/2006, P.555 |
| Keywords: Stitching interferometer, Wafer thickness, Wafer flatness |
|
Abstract : A pre-prototype measurement machine for measuring the geometry
of double side polished wafers has beendeveloped. The measurement
principle is based on a scanning double sided Fizeau interferometer with
whichthe front side and the back side flatness of a wafer are measured
simultaneously. Both flatness maps areused to derive the wafer thickness
variation. Field distortion of the optical system, alignment errors and
thethickness variations of the reference cavity are compensated by
self-calibrating techniques in order to achievea measurement uncertainty
in the order of several nanometers. |
| Measurement Technology for the Machine-Integrated Determination of Form Deviations in Optical Surfaces |
| R. Schmitt, D. Doerner /T. Pfeifer (1) |
| STC P, 55/1/2006, P.559 |
| Keywords: Quality Assurance, Mold, Interferometry |
|
Abstract : Quality inspection of ultra precise mold inserts is conducted
outside the manufacturing machine by using phase-shifting
interferometers (PSI). Reworking or a local correction of form
deviations is difficult, because the mold inserts have to be
repositioned in the machine tool. A promising way to overcome this
problem is the machine-integration of the measurement system. But due to
the sensitivity of PSI methods a direct integration into the machine
tool is possible only to a limited extend. A FFT-based measurement
technique was developed with reduced sensitivity. It was applied in a
injection molding machine for form testing of a clamped mold insert with
80 ?C process temperature. |
| Development of a New Interferometric Measurement System for Determining the Main Characteristics of Gauge Blocks |
| Y. Kuriyama, Y. Yokoyama, Y. Ishii, J. Ishikawa /H. Makino (1) |
| STC P, 55/1/2006, P.563 |
| Keywords: Interferometry, Measurement, Gauge block |
|
Abstract : A new interferometric measurement system for gauge blocks
which does not require wringing onto an auxiliary platen has been
developed. The main characteristics of gauge blocks measured in this
system aredimensions, coefficients of thermal expansion (CTE) and
temporal stability. The repeatability is better than 3 nm for
dimensional measurements and a comparison of this system to a
conventional one showed good agreement. In CTE measurements, the
expanded uncertainty is 3.5 x 10^-8 / K. Precision temporal stability
measurement is improved since wringing is not required. This
interferometer enables better quality control in our gauge block
production process. |
| Study of a small-sized Ultrasonic Probe |
| K.Hidaka /P.H.J. Schellekens (1) |
| STC P, 55/1/2006, P.567 |
| Keywords: Ultrasonic, Sensor, Probe |
|
Abstract : This paper presents the design and testing of a small-sized
ultrasonic probe that is able to measure non destructively a micro-part
surface form with sub micro Newton measuring force. A force sensor
installed in the probe has a Ni-Cr stylus of 3 mm length that is axially
vibrated by a bulk-PZT at longitudinal resonant frequency. At the end of
the stylus a glass tip ball of 30 mm diameter is mounted. The stylus
aspect ratio of 100 is around the highest level available. An algorithm
for autonomous profiling measurement using output-signal of the
ultrasonic probe is presented as well as measurement results of a
micrometer sized hole and gear surface form. So far measurement
uncertainty is in the micrometer region but it is expected that this can
be reduced. |
STC S |
| Principal Factors Affecting the Sub-Micrometer Grooving Mechanism of SiC Thin Layers by a 355 nm UV Laser |
| Y. Furukawa (1), H. Sasahara, A. Kakuta, K. Chuma |
| STC S, 55/1/2006, P.573 |
| Keywords: Grooving, Integrity, Laser micro machining |
|
Abstract : The machining of micro holes and grooves on single crystal SiC
thin layers by a UV laser (355 nm wave length and 15 ps pulse width) is
reported. It was verified that an optimum threshold, where both laser
sublimation and photonic ablation can take place at the same time in
order to obtain a micro sharp groove as 2 mm pitch and 0.4 mm depth,
must be selected. Theoretically, laser photonic ablation may take place
at a certain amount of laser fluence, and then SiC is sublimed once the
influence exceeds another limit, and therefore, there is an optimum
threshold between these two limits of laser fluence. |
| Miniaturized Optical Measurement Methods for Surface Nanometrology |
| X. Jiang, D. Whitehouse (1) |
| STC S, 55/1/2006, P.577 |
| Keywords: Measurement, Optical, Surface |
|
Abstract : This paper introduces some new types of optical surface
measurement methods. One method uses spatiallight-wave scanning to
replace mechanical stylus scanning, and an optical fibre interferometer
to replaceoptically bulky interferometers either of which are involved
in almost all current surface measurement (stylusand optical) methods.
The optical principle is based on measuring the phase shift of light
reflected from thesurface by using a combination of
Wavelength/Frequency-Division-Multiplexing (WDM or FDM) and FibreBragg
Grating (FBG) techniques. The WDM/FDM-FBG techniques provide the
implementation of phase-todepthand wavelength-to-field detection, and
can offer a large dynamic measurement ratio (range/resolution)with a
high signal-to-noise ratio (robustness). |
| Modeling of Surface Generation in Contour Grinding of Optical Molds |
| C. Heinzel, D. Grimme /A. Moisan (1) |
| STC S, 55/1/2006, P.581 |
| Keywords: Modeling, Surface, Grinding |
|
Abstract : The objective of this paper is the modeling of kinematics of
precision contour grinding and resulting workpiece topography. Changes
within the contact zone of grinding wheel and workpiece as well as speed
ratios are analyzed and evaluated. The generated surface patterns caused
by the runout of the grinding wheel aresimulated. In the
kinematic-geometrical model single grains on the peripheral surface of a
grinding wheel, which interact with the workpiece, are considered. After
describing the kinematics of the contour grinding process, changes in
feed speeds and rotational speed ratios are examined and their effects
on generated surfaces are simulated and compared with ground surfaces. |
| Photothermal Investigation of Ti-Cu-N and Ti-Ni-N PVD Films |
| H. Prekel, M.J. Klopfstein, M. Giesselbach, S. Patzelt, R. Ghisleni, D.A. Lucca (1), G. Goch (1), H. |
| STC S, 55/1/2006, P.585 |
| Keywords: Coating, Physical Vapour Deposition (PVD), Photothermal radiometry |
|
Abstract : Thin titanium based PVD films on steel substrates are
promising material combinations for high quality moulding tools required
for the manufacturing of complex optical components. The chemical film
composition and PVD process parameters determine the thermal and
mechanical layer properties, which must remain stable at high
temperatures during the moulding process. This paper describes the
investigation of thermal and mechanical film properties with respect to
film composition and thermal treatment at temperatures typical for
moulding processes. |
| Sol-Gel Coatings for High Precision Optical Molds |
| A. Mehner, H.-W. Zoch, W. Datchary, G. Pongs /H. Kunzmann (1) |
| STC S, 55/1/2006, P.589 |
| Keywords: Coating, Machining, Sintering |
|
Abstract : The demand for high precision molds for the mass production of
optical components is increasing. This paper describes a new approach
for manufacturing precision optical molds. Firstly, thin ceramic sol-gel
ZrO2-coatings were deposited onto pre-machined steel and nickel alloy
molds. These coatings successfully solve the problem of sticking between
the glass and the metal molds during high precision hot-pressing of
glass lenses. Secondly, diamond machinable wear resistant sol-gel
SiO2-xCy-coatings were deposited onto pre-machined steel molds for
injection molding. Mechanical coating properties like hardness, elastic
modulus and density were measured as a function of the sol-gel
processing parameters. |
| Size Effects on Surface Generation in Micro Milling of Hardened Tool Steel |
| G. Bissacco, H.N. Hansen (2), L. De Chiffre (1) |
| STC S, 55/1/2006, P.593 |
| Keywords: Micromachining, Milling, Surface |
|
Abstract : This paper presents the results of an extensive experimental
investigation concerning size effects on surface generation by ball nose
and flat end micro milling hardened tool steel. Cutting parameters were
selected on the basis of a modular description of the uncut chip
geometry. A theoretical model of the generated surfaces was used as a
reference and compared with measurement results and visual inspection
using an SEM. Two main effects have been observed on the tool-work
material interaction at micro scale. These are responsible for the
limited reduction of the roughness amplitude parameters with tool
diameter and occur when the cutting edge radius to uncut chip thickness
ratio becomes critical. |
| Investigation on Grinding Characteristics and Surface-Modifying Effects of Biocompatible Co-Cr Alloy |
| H. Ohmori (2), K. Katahira, Y. Akinou, J. Komotori, M. Mizutani |
| STC S, 55/1/2006, P.597 |
| Keywords: Biomedical, Grinding, Finishing Process |
|
Abstract : Co-Cr alloy used as a biomaterial is required to possess
excellent resistance to corrosion, wear, and biocompatibility. In the
present work, we performed Electrolytic In-Process Dressing grinding on
Co-Cr alloy, and evaluated the processing characteristics and resulting
surface properties. Final finishing using a #8000 wheel produced an
extremely smooth ground surface with a roughness Ra of 7 nm. In
addition, as compared with the conventionally polished samples, the
ground samples demonstrated superior surface hardness and
biocompatibility. These advantages can be attributed to the diffusion of
several kinds of elements during the grinding process and the effect of
grinding fluid compositions. |
| Effects of Fluids on the Surface Generation in Material Removal Processes - Molecular Dynamics Simulation - |
| R. Rentsch, I. Inasaki (1) |
| STC S, 55/1/2006, P.601 |
| Keywords: Cutting, Surface, Simulation |
|
Abstract : Molecular dynamics (MD) simulation has been attractive in
order to gain deeper understanding of microscopic material behavior and
have been applied to study various materials properties and phenomena.
Most of the MD material removal process simulations were focusing on the
material removal mechanisms, chip and surface generation. The
state-of-the-art in MD grinding, scratching, cutting or indentation
simulation did not consider fluids or an atmosphere (neither gas nor
liquid). Hence, the environment represents high vacuum with no heat
convection. In this contribution we will describe an extension of the
state-of-the-art MD material removal process modeling to consider fluids
like coolants and elaborate on its impact on the surface generation and
the tribological contact conditions on basis of MD simulation results. |
| Surface Evolution during the Chemical Mechanical Planarization of Copper |
| W. Che, A. Bastawros, A. Chandra /P.M. Lonardo (1) |
| STC S, 55/1/2006, P.605 |
| Keywords: Surface, Polishing, Nano indentation |
|
Abstract : Stressed surfaces are configurationally unstable under
chemical etching wherein they may evolve to reduce their total energy.
This paper investigates how such an effect may influence the
planarization rate in a Chemical Mechanical Planarization (CMP) process.
Nano-wear experiments on electro-plated copper surfaces have been
conducted with systematic exposures to chemically active slurry. The
nano-wear experiments have been first performed to generate local
variation of the residual stress levels, followed by chemical etching to
investigate the variation of the wear depth and the evolution of surface
topography. It is found that the residual stress caused by the
mechanical wear enhances the chemical etching rate. |
| Surface Interactions in Steel Polishing for the Precision Tool Making |
| O. Dambon, A. Demmer /J. Peters (1) |
| STC S, 55/1/2006, P.609 |
| Keywords: Surface, Polishing, Steel |
|
Abstract : The polishing of steel becomes more and more important due to
the increasing qualitative demands on the surface finish of tools and
dies. But despite many research activities in the recent years, the
polishing process is still characterized by a poor knowledge of the
relevant mechanisms. Especially the complex interactions among the
system components cannot be sufficiently described, yet. In this paper,
the relevant interactions between the polishing abrasive and the steel
surface are discussed. Starting from a phenomenological view on the
removal behaviour of different steel alloys, a model for the wear
resistance of the steel surface is presented. It shows that next to the
hardness of the material particularly the mechanisms of micro-ploughing
and micro-cutting determine the removal behaviour. Furthermore, the
influence of the workpiece material on the removal rates is discussed. |
| A Novel Surface Finishing Technique for Microparts Using an Optically Controlled |
| Y. Takaya (2), K. Hida, T. Miyoshi, T. Hayashi |
| STC S, 55/1/2006, P.613 |
| Keywords: Surface finishing, Micropart, Optical force |
|
Abstract : Fine machining and surface finishing in a local portion on a
micropart surface are needed to optimize mechanical and optical function
of a microsystem such as MEMS (Micro-Electro-Mechanical System) and
MOEMS (Micro-Opto-Electro-Mechanical System) for individual specific
applications. So the novel nano-process technique using a microparticle
tool controlled by an optical radiation pressure is proposed. This paper
focuses on the surface finishing of a micropart made of single-crystal
silicon. In order to verify the availability of the proposed method for
the local nano-polishing, polishing experiments for a rough silicon
surface with Rq of several dozen nanometers are performed using an
optically controlled silica particle with a diameter of 3 micrometer as
a micro-tool. The experimental results reveal that the surface roughness
with a spatial wavelength ranging from 1 micrometer to 10 nanometer,
over an area of several square micrometers, can be improved to the order
of nanometers. |