CIRP ANNALS 2007
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STC A |
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Incorporating Lifecycle Considerations in Axiomatic Design
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E. Stiassnie, M. Shpitalni (1)
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STC A, 56/1/2007, P.1
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Keywords: Product lifecycle, Lifecycle analysis, Axiomatic design |
Abstract : At the outset of designing a new product, knowledge about
the product is limited, but the designer has a considerable amount of
design freedom. Considering the environmental implications of a
product design early in the design phase is a crucial step in
achieving an environmentally efficient product. By applying the
axiomatic approach to a product's design, the designer can ensure that
the final embodiment of the product or service satisfies the
obligatory and necessary set of functional requirements and
constraints, including environmental issues. In this paper we show how
the integration of environmental considerations early in the process
of axiomatic design can lead to the development of an
environmental-friendly product or service. The paper demonstrates an
artificial case study of designing a modern manufacturing system. A
major issue investigated in this work is the possibility of assessing
environmental performance (or environmental-related information)
already in the preliminary stages of the design process. An upper
bound for the probability of a product failing to satisfy
environmental requirements is introduced. In addition, the suitability
of lifecycle analysis to the assessment of products during the process
of axiomatic design is discussed.
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Optimization of Steel Production to Improve Lifecycle Environmental Performance
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J.W. Sutherland (2), K.R. Haapala
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STC A, 56/1/2007, P.5
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Keywords: Lifecycle, Decision making, Steelmaking |
Abstract : To reduce lifecycle impacts, manufacturers require an
understanding of how design, manufacturing, and other decisions
influence their eco-footprint across all product lifecycle stages,
e.g., manufacturing, use, and end-of-life. However, few tools exist to
address manufacturing impacts on the environment. For many products,
steelmaking accounts for the majority of manufacturing energy use,
with process wastes also representing significant concerns. A
predictive model for a steelmaking electric arc furnace (EAF) is
briefly described and is then used to illustrate how environmental
performance can be optimized for a given steel alloy. Process inputs
are identified that minimize a variety of environmental measures.
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An Integrated Methodology to Estimate the External Environmental Costs of Products
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S. Kara (2), S. Manmek, H. Kaebernick (1)
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STC A, 56/1/2007, P.9
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Keywords: Conceptual Design, Lifecycle Assessment, Environmental Impact Cost |
Abstract : Environmental costs of products are closely related to
their environmental impacts. This paper presents a methodology to
estimate the environmental costs of products during the concept design
phase by integrating a Simplified Life Cycle Assessment (SLCA)
methodology with Economic Valuation (EV) methods such as EPS2000d,
EXMOD and Ecosense. The new methodology estimates the environmental
performance indicators for each stage of the product life cycle by
using the SLCA, and obtains the cost values from the most suitable EV
method. A number of passive and active products were used to prove the
concept and demonstrate the efficiency of the methodology.
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'Odds Algorithm'-based Opportunistic Maintenance Task Execution for Preserving Product Conditions
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B. Iung, E. Levrat, E. Thomas / M. Veron (1)
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STC A, 56/1/2007, P.13
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Keywords: Maintenance, Decision-Making, Odds algorithm |
Abstract : Today, a new role for maintenance exists to enhance the
eco-efficiency of the product life cycle. The concept of "life
cycle maintenance" emerged to stress this role leading to push,
at the manufacturing stage, an innovative culture wherein maintenance
activities become of equal importance to actual production
activities. This equivalence requires mainly considering the
integration of the maintenance and production strategy planning for
developing opportunistic maintenance task keeping conjointly the
product - production - equipment performances. In this paper, a novel
approach is proposed for integrating maintenance and production
planning. The approach uses the "odds algorithm" and is
based upon the theory of optimal stopping. The objective is to select,
among all the production stops already planned, those which will be
optimal to develop maintenance tasks keeping the expected product
conditions. It combines criteria such as functional performance and
component reliability. Approach feasibility is shown on a practical
example.
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An Alternative Approach for the Cost-efficient Laser Welding of Zinc-coated Sheet Metal
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H. Bley (1), L. Weyand, A. Luft
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STC A, 56/1/2007, P.17
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Keywords: Welding, Nd:YAG laser, Zinc-coated sheet metal |
Abstract : Laser welding becomes more and more important for body in
white assembly in automotive industry. But even if the modern
technology offers a lot of new possibilities, laser welding of
zinc-coated sheet metal is still a challenge - special effort is
necessary to produce acceptable weld seams in the lap joint
configuration. Already existing concepts oftentimes lead to enlarged
process chains and additional costs. Therefore, this paper presents an
alternative approach for laser welding of zinc-coated sheet metal with
the objective to guarantee high quality laser welding and to save
costs. Moreover, first results of welding experiments are shown.
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An electrostatic sorting device for microparts
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G. Fantoni, M. Porta, M. Santochi (1)
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STC A, 56/1/2007, P.21
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Keywords: microassembly, microfactory, electrostatic sorting |
Abstract : The parallel handling of microcomponents is a strategy to
speed up the microassembly of hybrid microproducts. This paper
presents an electrostatic device for parallel sorting. The sorting of
components has been achieved with a combination of a vibrating
platform, to reduce friction and adhesion, and an electrostatic
potential with several minima. Thanks to a suitable design of the
electrostatic sorting device, only one component is attracted and
trapped in each minimum. The reliability and accuracy of the sorting
system have been proved by measuring the actual positions of the
components by a vision system.
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Flexible Automation for the Assembly in Motion
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G. Reinhart (1), J. Werner
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STC A, 56/1/2007, P.25
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Keywords: Assembly in Motion, Automation, Flexibility |
Abstract : Automation in flow assembly lines is hindered by the need
for clocked lines when using automated systems. Geometrical
inaccuracies and vibrations of the conveyor systems complicate the use
of automation as well. The assembly in motion, meaning a robot system
which is synchronized in all degrees of freedom to the moving conveyor
belt, is a promising attempt to solve these difficulties. Main
advantages of synchronized assembly are the avoidance of buffers and
the reduction of the throughput time. The automated assembly in motion
is realized by using mechatronic components and innovative feedback
algorithms which are currently under development.
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Development of Specific Technologies and Assembly Systems for the New Challenge of Electro-Optical Devices
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K. Feldmann (1), D. Craiovan, M. Roesch
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STC A, 56/1/2007, P.29
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Keywords: Assembly, Automation, Electro-Optical Device |
Abstract : Today's information and communication systems are
especially characterized by their capability and reliability of high
data rate transmission. An integration of optical wave guides into
printed circuit boards allows a hybrid electronics packaging in order
to increase the data transmission rate. The success of this technology
depends in particular on the availability of efficient production
solutions. For this reason, the development of automated assembly
systems for electro-optical components has become a main research
field at the Institute for Manufacturing Automation and Production
Systems. This paper describes the challenges of the placement systems
and presents a continuous process chain for the automated assembly of
electro-optical components.
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Bioanalogous Mechanical Joints for Authorized Disassembly
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K. Saitou, M. Shalaby, L.H. Shu (2)
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STC A, 56/1/2007, P.33
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Keywords: Disassembly, Joining, Biologically inspired design |
Abstract : This paper describes bioanalogous, or biomimetic,
lock-and-key mechanical joints that enable disassembly that is easy
but only by those authorized. The problem is motivated by the
increasing need for economical disassembly of products by original
equipment manufacturers (OEMs) while protecting high-value components
from theft and third-party recyclers. The joints must be easy to
disengage with the 'key' but difficult to disengage
without it. They also must be easy to manufacture, assemble and
provide sufficient stiffness. An analogous biological phenomenon
involving enzyme-substrate interaction was used to inspire the
development of a heat-reversible snap-locator joint system.
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Development of Hybrid Assembly Workplaces
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S. Consiglio, G. Seliger (1), N. Weinert
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STC A, 56/1/2007, P.37
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Keywords: Assembly, Robot, Hybrid Workplace |
Abstract : In times of shortened innovation cycles, increasing product
variation and demands for faster delivery, the flexibility of
production systems is crucial for success. Hybrid workplaces,
dynamically configurable for both human workers and robots, help to
increase the flexibility. The robot kinematics employed, the available
sensors, and the grasping conditions involved in the assembly process
mainly determine the changeover effort of a workplace. In this paper,
different concepts for hybrid workplaces are introduced and compared
with respect to investment costs and configuration effort. Concept
application and evaluation are illustrated by final assembly of flat
screen monitors.
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Co-Evolution of Product Families and Assembly Systems
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A. Bryan, J. Ko, S.J. Hu (2), Y. Koren (1)
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STC A, 56/1/2007, P.41
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Keywords: Assembly System, Product Family, Co-evolution |
Abstract : To cope with the intense global competition that is
characterized by high product variety and short life cycles,
manufacturers need to share manufacturing systems across products and
product generations. Co-evolution of product families and assembly
systems is proposed as a novel methodology for the joint design and
reconfiguration of product families and assembly systems over several
product generations. The co-evolution methodology capitalizes on the
opportunities for design and assembly system reuse that are offered by
modular product architectures and reconfigurable assembly systems. As
a result, co-evolution can lead to reduced product development costs
and increased responsiveness to market changes.
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Micro Handling Devices Supported by Electrostatic Forces
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J. Hesselbach (2), J. Wrege, A. Raatz
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STC A, 56/1/2007, P.45
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Keywords: Handling, Electrostatic, Microgripper |
Abstract : The handling of micro parts made of dielectric material can
be affected by electrostatic forces. This work presents new handling
devices taking advantage of electrostatic forces. These forces are
generated by simple configurations of electrodes or by charges located
on surfaces of insulators. High resolution force measurements show
electrostatic effects such as gas discharges and leak currents. Active
neutralization was applied by ionizers to discharge the handling
devices and the parts to be handled. This method improved the process
reliability significantly. Further, the influence of surface charges
on the process reliability of pick and place operations of mechanical
micro grippers was investigated.
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Augmented Reality Aided Assembly Design and Planning
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S.K. Ong (2), Y. Pang, A.Y.C. Nee (1)
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STC A, 56/1/2007, P.49
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Keywords: Assembly Design, Product Evaluation, Augmented Reality |
Abstract : This paper presents a methodology that integrates the
assembly Product Design and Planning (PDP) activities with the
Workplace Design and Planning (WDP) activities to improve the
efficiency and quality of assembly design and planning at the early
design stage. This methodology is implemented in an augmented reality
(AR) assembly environment, where engineers can design and plan a
product assembly and its assembly sequence through manipulating
virtual prototypes in a real assembly workplace. In this AR
environment, WDP information are fed back to the designers and
engineers in real-time to aid them in making better decisions in
assembly design and planning.
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STC C |
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Requirements for Ductile-mode Machining Based on Deformation Analysis of Mono-crystalline Silicon by Molecular Dynamics Simulation
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H. Tanaka, S. Shimada (1), L. Anthony
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STC C, 56/1/2007, P.53
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Keywords: Simulation, Silicon, Ductile-mode machining |
Abstract : To obtain scientific guidelines for ductile-mode machining,
nano-indentation, nano-bending, and nano-machining of defect-free
mono-crystalline silicon are investigated by molecular dynamics
simulation. Results show that amorphous phase transformation of
silicon is a key mechanism for inelastic deformation, and stable
shearing of the amorphous is necessary for ductile-mode
machining. Stress analysis suggests that stable shearing takes place
under a compressive stress field. In practice, a sharp cutting edge
tool with a large negative rake angle should be used for effective
ductile-mode machining, and vibration machining should be applied for
larger depths of cut as it enlarges the amorphous region in front of
the cutting edge.
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Grain Size and Orientation Effects When Microcutting AISI 1045 Steel
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A. Simoneau, E. Ng, M.A. Elbestawi (1)
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STC C, 56/1/2007, P.57
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Keywords: Micromachining; Finite Element Method; Microstructure |
Abstract : Microstructure has a significant effect on microscale
cutting. This paper investigates the effect of grain size and
orientation during microcutting of AISI 1045 steel. From experimental
and finite element (FE) modeling observations, classification of the
cutting scale is dependent upon the grain size of the workpiece
material. Surface dimple size can be reduced provided there is a
reduction in grain size and orientation of grain boundaries are not
parallel to the shear plane during microcutting. Incorporating
microstructures into a FE cutting model yields a more accurate
reflection of the workpiece material's stress-strain behaviour
in the primary shear zone.
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Finite Element Modeling and Cutting Simulation of Inconel 718
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E. Uhlmann (2), M. Graf von der Schulenburg, R. Zettier
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STC C, 56/1/2007, P.61
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Keywords: Turning, Chip formation, Finite Element Method |
Abstract : Segmented chips are often found in high-speed-cutting. This
type of chip formation can be traced back to adiabatic shear
bands. The reference workpiece material is the Nickel-based alloy
Inconel 718, which shows an affinity to segmented chip formation. A
realistic simulation of the chip formation and of the related cutting
forces and chip temperatures serve to better process understanding. By
implementing a material model into the FE-simulation which besides
strain, strain rate and temperature includes ductile damage, a
realistic description of the material behavior becomes possible. The
results of the experiments and of the 2D- and 3D-simulations correlate
well.
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Residual Stress Modeling in Orthogonal Machining
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S.Y. Liang, J-C.Su / G.D. Lahoti (1)
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STC C, 56/1/2007, P.65
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Keywords: Residual stress modeling, Analytical modeling, Orthogonal cutting |
Abstract : A predictive model for residual stresses in orthogonal
cutting is presented. It uses process conditions as inputs and
predicts surface and sub-surface residual stress profiles due to
machining. The model formulation incorporates cutting force and
cutting temperature predictions and utilizes those parameters to
define the thermo-mechanical loading experienced by the workpiece. The
stresses at the cutter edge hone and in the shear plane are considered
in a rolling/sliding contact algorithm which admits kinematic
hardening for non-proportional plasticity with subsequent stress
relaxation to meet boundary conditions. Model predictions are compared
to published experimentally-measured residual stresses under various
cutting conditions for validation.
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ALE simulation of orthogonal cutting: a new approach to model heat transfer phenomena at the tool-chip interface
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E. Ceretti, L. Filice (2), D. Umbrello, F. Micari (1)
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STC C, 56/1/2007, P.69
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Keywords: Cutting, Finite element method, Heat transfer coefficient |
Abstract : This paper presents a new procedure to evaluate the global
heat transfer coefficient in orthogonal cutting. The knowledge of the
actual heat transfer conditions is a fundamental issue as far as the
life, tool wear and tool substitution interval are regarded. More in
detail, an Arbitrary Lagrangian-Eulerian approach was utilised to
model orthogonal cutting process and the numerical simulations were
validated by making experimental tests for identifying cutting forces
and internal tool temperatures. A mild steel was cut utilising both an
uncoated (WC) and a coated (TiN) tool. On the basis of both
experimental and simulative data, a consistent model of the global
heat transfer coefficient as function of the local pressure and
temperature at the tool-workpiece interface was developed.
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Fundamental Wear Mechanisms when Machining Austempered Ductile Iron (ADI)
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F. Klocke (1), C. Klöpper, D. Lung, C. Essig
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STC C, 56/1/2007, P.73
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Keywords: Machinability, Microstructure, Finite Element Method (FEM) |
Abstract : Austempered Ductile Iron (ADI) is
characterised by improved mechanical properties but low machinability
compared to conventional ductile iron materials and steels of similar
strengths. The mechanical properties of ADI are achieved by a very
fine austenitic-ferritic microstructure. However this unusual
microstructure significantly affects mechanical and thermal machining
properties. A keen understanding for the interactions of
microstructure, chip formation, machining properties, cutting material
and wear mechanisms is essential for the optimisation of the cutting
process. This paper describes material and machining investigations as
well as cutting simulations to reveal the wear mechanisms being
responsible for the low machinability of ADI.
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An Innovative Methodology for the Performance Evaluation of Coated Cemented Carbide Inserts in Milling of Inconel 718
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K.-D. Bouzakis (1), N. Michailidis, S. Gerardis, M. Batsiolas, M. Papa, E. Lili, J. Mirisidis, J. Mu
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STC C, 56/1/2007, P.77
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Keywords: Physical vapor deposited (PVD) coating, Milling, Nickel alloys |
Abstract : The performance of cemented carbide inserts coated with
various PVD-films in milling Inconel 718 is evaluated by innovative
analytical and experimental methods. Three PVD films with different
micro and macro structures were applied. The coatings' strength
properties were detected by nanoindentations and by impact tests at
various temperatures. These results were considered in FEM
calculations of the material removal process to determine the
mechanical and thermal loadings of the cutting wedge. Employing this
innovative methodology, it is possible to capture proactively the
effect of the cutting conditions on tool wear, thus reducing the
effort dedicated in traditional sequential cutting experimentation.
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Virtual High Performance Machining
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Y. Altintas (1), D.S. Merdol
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STC C, 56/1/2007, P.81
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Keywords: Virtual, Milling, Optimisation |
Abstract : The goal of future manufacturing is to design, test and
manufacture parts in a virtual environment before they are
manufactured on the shop floor. This paper presents a generalized
process simulation and optimization strategy for 2 1/2 axis milling
operations to increase Material Removal Rate (MRR) while avoiding
machining errors. The process is optimized at two stages. Optimal
spindle speed, radial and axial depth of cut are recommended to
process planner by considering the chatter, and spindle's
torque/power limits. The cutter-part engagement conditions are
extracted from CAD system by geometrically processing the NC program
and part geometry. Long tool path segments are broken into smaller
segments whenever the geometry varies. The spindle speed and feed
fields of the NC program are automatically optimized by constraining
maximum torque, power, tool deflection and chip load set by the
user. The acceleration and speed limits of the machine tool feed
drives are considered to prevent frequent variations of the feed
unnecessarily. The optimization is experimentally verified by milling
a helicopter gear box cover on a high speed, horizontal machining
centre.
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Improvement of Dynamic Properties in Milling by Integrated Stepped Cutting
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B. Karpuschewski (1), S. Batt
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STC C, 56/1/2007, P.85
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Keywords: Face Milling, Process stability, Tool optimisation |
Abstract : Die and mold machining usually necessitate employment of
milling tools with long shanks. However, economic and technical design
requirements often enforce low frequency structural vibration
characteristics in work-pieces, especially in an area distanced from
the tool holder. These structurally unstable designs pose a challenge
for milling operations. The associated vibrations invariably reduce
the quality of the work-piece produced and drastically increase
average processing time and costs. This paper deals with cutting
techniques used in face milling operations under semi-stable and
unstable conditions. The strategy to use milling tools with integrated
stepped cutting passes shows, that the use of smaller cutting ratios
b/h, the chatter characteristics of the process could be significantly
improved, thereby increasing the performance of the milling process.
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An Integrated Force Sensor Solution for Process Monitoring of Drilling Operations
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G. Byrne (1), G.E. O'Donnell
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STC C, 56/1/2007, P.89
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Keywords: Monitoring, Drilling, Integrated force sensor |
Abstract : Two piezo electric force sensor rings were developed and
integrated into a direct driven motor spindle for online process
monitoring of machining processes. Experimental results are presented
which demonstrate the performance of the integrated force sensor
during drilling operations. Performance comparisons are made between
the integrated force sensors and traditional monitoring sensors such
as motor power and acoustic emission. The non cutting influences such
as spindle dynamic loading contained in the integrated sensor signals
are identified. The potential application of the integrated force
sensors for process monitoring encompassing tool condition monitoring,
spindle condition monitoring and collision detection is demonstrated.
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Temperature Measurement of Cutting Edge in Drilling - Effect of Oil Mist -
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T. Ueda (2), R. Nozaki, A. Hosokawa
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STC C, 56/1/2007, P.93
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Keywords: Drilling, Temperature, Mist lubrication |
Abstract : In drilling, the temperature of the cutting edges of a
drill is measured using a two-color pyrometer with an optical fiber. A
cemented carbide drill with a diameter of 10 mm is used as a cutting
tool, and carbon steel, cast iron and aluminum die-cast alloy are used
as work materials. The temperature distribution along the cutting edge
of a drill is measured and the influence of spindle speed and feed
rate on the tool temperature is investigated. The maximum tool
temperature is observed during the drilling of carbon steel. The
effect of oil mist supplied from oil holes in the drill on the tool
temperature is examined and the result is compared to that in turning
and end milling. The temperature reduction in oil mist turning is
approximately 5%, while in oil mist end milling it is 10-15% and that
in oil mist drilling is 20-25% compared to the temperature in dry
cutting.
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Tribological Action and Cutting Performance of MQL Media in Machining of Aluminum
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T. Wakabayashi, S. Suda, I. Inasaki (1), K. Terasaka, Y. Musha, Y. Toda
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STC C, 56/1/2007, P.97
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Keywords: Cutting, Environmental, Tribology |
Abstract : The tribological action of MQL media and atmospheric
carrier gases was investigated using controlled atmosphere cutting
apparatus. The investigation demonstrated their adsorption behavior
onto metal surfaces was in close connection with the cutting
performance of a lubricant synthetic ester and carrier gases in
practical MQL machining. In particular, the presence of oxygen
resulted in unfavorable cutting phenomena in MQL machining of
aluminum. A unique technique of MQL media treatment was further
proposed to prepare oil mist sprays containing microdroplets of
water. This advanced technique provided some possibilities of
improving the tribological action of MQL media in machining of
aluminum.
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Performance Testing of Cryogenic CO2 as Cutting Fluid in Parting/Grooving and Threading Austenitic Stainless Steel
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L. De Chiffre (1), J. L. Andreasen, S. Lagerberg, I.-B. Thesken
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STC C, 56/1/2007, P.101
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Keywords: Machining; cutting fluid; stainless steel |
Abstract : Experimental investigations were carried out in which the
efficiency of cryogenic CO2 was compared to that of a commercial water
based product with respect to tool life, cutting forces, chip disposal
and workpiece surface finish. The experimental results show that CO2
applied at a rate of about 6g/s is an efficient coolant for threading
as well as for parting/grooving stainless steel. Threading can be
carried out with gas alone but the best performance was obtained
adding 6ml/min unadditivated vegetable oil to the gas. In the case of
parting/grooving, addition of oil (10ml/min) to the gas is mandatory.
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Machining of High Strength Light Weight Alloys for Engine Applications
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K. Weinert (1), D. Biermann, S. Bergmann
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STC C, 56/1/2007, P.105
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Keywords: Wear, Turning, Material |
Abstract : The use of high strength materials with low density in
engines and vehicles gains more and more intention for the reduction
of weight in moving parts. Currently, γ-titaniumaluminides as
well as aluminum-metal-matrix-composites are considered as appropriate
materials for this purpose. In spite of their outstanding material
properties, problems occur when machining operations are carried
out. These problems emerge from the high strength and the abrasive
reinforcing particles. This paper presents research on the machining
of a γ-TiAl-alloy as well as an Al-MMC-alloy. Investigations of
the turning process were focused on ascertaining conditions for an
economical and a high-quality machining process.
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Distortion Engineering - Identification of Causes for Dimensional and Form Deviations
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E. Brinksmeier (1), J. Sölter, C. Grote
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STC C, 56/1/2007, P.109
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Keywords: Bearing, Distortion Engineering, Turning |
Abstract : Distortion of power transmission parts after heat treatment
is influenced by each step of the process chain, ranging from material
production to hard-machining. However, an experimental analysis for
each production step in the manufacture of bearing rings has shown
that distortion is significantly influenced by turning before heat
treatment. Elastic ring deformation caused by fixing the workpiece in
the chuck leads to a variation of the depth of cut and polygonal form
deviations occur after machining. In addition the cutting process
induces locally varying residual stresses which also contribute to
dimensional and form deviations of machined rings. In this paper
results from experimental investigations of the principle physical
causes for the distortion of bearing rings are presented and
discussed. Finally, strategies for the minimization of distortion are
derived.
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Biocompatible Magnesium Alloys as Absorbable Implant Materials - Adjusted Surface and Subsurface Properties by Machining Processes
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B. Denkena (2), A. Lucas
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STC C, 56/1/2007, P.113
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Keywords: Cutting, Biomedical, Corrosion |
Abstract : Biocompatible magnesium alloys offer great potential as
absorbable implant materials. They degrade within a certain time span
after surgery and are therefore suitable to temporarily accomplish
medical functions, for instance as bone screws or plates. These
implants support fractured bones until healing. This paper describes
approaches to control the corrosion of the magnesium and hereby the
degradation kinetics of the implant in the organism. The degradation
kinetics is adjusted via surface (e.g. topography) and subsurface
properties (e.g. residual stresses) of the implant determined by the
manufacturing process. Consequently, a specific degradation profile
adapted to the individual medical application is achievable.
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Heat Flow Simulation for Dry Machining of Power Train Castings
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J. Fleischer (2), R. Pabst, S. Kelemen
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STC C, 56/1/2007, P.117
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Keywords: Cutting, Boring, Heat Input |
Abstract : Dry machining of power train components (eg. cylinder
blocks, heads) is very challenging. High heat input due to the lack of
coolant can result in an inhomogeneous temperature distribution
leading to omni directional distortion. This distortion can be
calculated using FEM simulation. It requires however a detailed
knowledge about the heat input of each operation. So far this can only
be determined by extensive experiments. The aim of this paper is to
present a model describing the heat input as a function of cutting
parameters and tool geometry. Based on this model the heat input can
be calculated. This allows the simulation and optimization of the
operation sequence.
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5-axis Control Ultra-precision Machining of Complex-shaped Mirrors for Extreme Ultraviolet Lithography System
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H. Takino, T. Kawai, Y. Takeuchi (1)
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STC C, 56/1/2007, P.123
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Keywords: Ultra-precision, Milling, Fly-eye mirror |
Abstract : The study deals with the manufacture of novel mirrors, an
arc-shaped fly-eye mirror and a rectangular fly-eye one, for an
extreme ultraviolet lithography system. Both mirrors have a complex
reflective surface consisting of many small spherical mirror
elements. A method is proposed to accurately realize such mirrors,
using ultraprecision 5-axis control machining. The method enables to
manufacture spherical surfaces with any radius, without changing the
tool shape. Furthermore, another advantage of the method is that the
sphericity of the resulting surfaces is independent of tool shape
accuracy. By using this method, two kinds of fly-eye mirror with
sixteen mirror elements are successfully fabricated.
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Elliptical Vibration Cutting of Tungsten Alloy Molds for Optical Glass Parts
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N. Suzuki, M. Haritani, J. Yang, R. Hino, E. Shamoto (2)
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STC C, 56/1/2007, P.127
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Keywords: Machining, Ultra-precision, Brittle materials |
Abstract : Elliptical vibration cutting is applied to ultra-precision
machining of tungsten alloy molds for optical glass parts in the
present research. The tungsten alloy is expected as a new mold
material instead of conventional ones such as sintered tungsten
carbide and CVD-silicon carbide. However, it cannot be finished
precisely by ordinary cutting because of rapid tool wear, brittle
fracture and adhesion to the tool. Therefore, the ultrasonic
elliptical vibration cutting is applied to the ultra-precision
machining of tungsten alloy. Practical ultra-precision molds are
obtained by the elliptical vibration cutting, and they are applied to
glass molding successfully.
|
|
Precision Cutting of Aspherical Ceramic Molds with Micro PCD Milling Tool
|
|
H.Suzuki,T.Moriwaki 1(1),Y.Yamamoto,Y.Goto
|
|
STC C, 56/1/2007, P.131
|
|
Keywords: Cutting, Mold, Diamond |
Abstract : In order to machine micro aspheric molds and dies made of
ceramics, micro milling tools made of polycrystal diamond (PCD) are
developed. Twenty cutting edges are ground and polished with diamond
wheels and loose abrasives on the edge of a small cylindrical PCD tool
shank. Some micro aspheric molding dies made of binder-less tungsten
carbide were cut with the PCD milling tool developed. The molds and
dies were cut in the ductile mode. The form accuracies of the micro
aspherical mold and the micro lens array mold obtained were less than
100 nmP-V and the surface roughness 15 nmRz.
|
STC Dn |
|
The Use of Virtual Reality Techniques during the Design Process: from the Functional Definition of the Product to the Design of its Structure
|
|
P. Zwolinski, S. Tichkiewitch (1), A. Sghaier
|
|
STC Dn, 56/1/2007, P.135
|
|
Keywords: Conceptual design, Product Lifecycle, Virtual Reality |
Abstract : During the design process, designers have to define the
structure of their product while considering its functional
definition. This design phase remains little assisted for
designers. In addition, as numerous options can be considered for the
end of life of a product (reuse, remanufacturing, recycling,…)
it becomes more difficult to obtain a compromise concerning the final
structure of the product. In this paper, we will show how the use of
virtual reality helps designers to transform the functional definition
of the product into the design of its structure, during the conceptual
design phase. The developed example will concern the design of a
bathroom scale.
|
|
Virtual Reality Approaches for Immersive Design
|
|
D. Weidlich (3), L. Cser (1), T. Polzin, D.Cristiano, H. Zickner
|
|
STC Dn, 56/1/2007, P.139
|
|
Keywords: Virtual Reality, 3D Interaction, Design |
Abstract : The current application of virtual reality (VR) systems in
the design process is limited mostly to design review. The reason for
this limitation is the different data formats used for CAD and VR
visualization. To use the benefits of VR during the design process,
solutions for immersive design - the model manipulation inside the VE
based on CAD data - are required. There are different approaches
allowing VR systems to work as an active development platform. Three
examples introduce the realization of the integration of CAD and VR
software at different levels by the online coupling of complete
applications or by integration of CAD core functionalities in VR
systems.
|
|
Impact of New 3D Numerical Devices and Environments on Redesign and Valorisation of Mechanical Systems
|
|
A. Bernard (1), F. Laroche, S. Ammar-Khodja, N. Perry
|
|
STC Dn, 56/1/2007, P.143
|
|
Keywords: 3D digitalisation, Design methods, Knowledge repository |
Abstract : The new generation of 3D digitalisation provides us with
additional possibilities for obtaining more complete information
regarding physical environments faster (a shop or part of a factory, a
mechanical system, etc…). Based on a general overview of a
given environment, it is possible to extract some repository data from
this basic information to structure the numerical model. Next some
complementary scans can be taken, depending on the level of detail and
the final valorisation objective for the numerical model. This
approach can be applied to the redesigning or the reconstitution of an
old mechanism and its simulation in virtual reality.
|
|
3D Reconstruction and Visualization of Microstructure Surfaces from 2D Images
|
|
D. Samak, A. Fischer (1), D. Rittel
|
|
STC Dn, 56/1/2007, P.149
|
|
Keywords: Microstructure surfaces, Engineering analysis, Visualization |
Abstract : This paper describes a stereophotogrammetry method that
reconstructs 3D microstructure surfaces from Scanning Electron
Microscope (SEM) images. The microstructure surfaces are represented
as 3D meshes with texture. The method's algorithm is based on
the following stages: a) computing 3D points from 2D matched points;
b) triangulating the 3D points into a 3D mesh; and c) mapping a 2D
image as a texture on the surface. The textured 3D surface exhibits
very realistic 3D microstructure surfaces for 3D visualization and
engineering analysis. The performance of the proposed method has been
analyzed and demonstrated on a variety of materials and complex
geometries.
|
|
Design Synthesis Framework for Dimensional Management in Multistage Assembly System
|
|
T. Phoomboplab, D. Ceglarek (1)
|
|
STC Dn, 56/1/2007, P.153
|
|
Keywords: Design synthesis, Integration, Dimensional management. |
Abstract : This paper proposes a design synthesis framework for
dimensional management in multistage assembly systems which integrate
the critical design tasks: (1) Tolerance Optimization; (2)
Multi-Fixture Layout Design; and, (3) Part-to-part Joint Design. The
proposed framework is based on the development of: (1) a new hybrid
Design Structure Matrix which integrates design tasks with design
configurations of Key Control Characteristics, and which has the
capability to model and analyze the interdependencies among design
tasks and constraints; and (2) Task Flow Chain which represents the
hierarchy of design tasks and is used to generate the sequence of
design tasks. The proposed methodology is illustrated and validated in
the process of designing configurations for automotive underbody
subassembly.
|
|
Meta-Modelling for Interoperability in Product Design
|
|
F.-L. Krause (1), U. Kaufmann
|
|
STC Dn, 56/1/2007, P.159
|
|
Keywords: Information, Modelling, Integration |
Abstract : Interoperability of tools for product design relies on the
utilization of common information models like ISO 10303 STEP. However
STEP is based on the EXPRESS modelling language which is not supported
by state-of-the-art software development tools. To reuse the huge
repository of information models defined in the STEP Application
Protocols transformations into other representations are needed. A
generic and sound approach is provided by OMG's Model Driven
Architecture (MDA) and Meta Object Facility (MOF). This paper
describes meta-modelling methods and tools for the coexistence and
integration of EXPRESS with UML, the commonly used modelling language
in modern software development environments.
|
|
Designing Product Reliability based on Total Product Lifecycle Modelling
|
|
F. Kimura (1), Y. Matoba, K. Mitsui
|
|
STC Dn, 56/1/2007, P.163
|
|
Keywords: Reliability Design, Product Lifecycle, Product Modelling |
Abstract : Due to the rapid progress of technology and severe
competition in market, recent industrial products are required to
exhibit high quality and functionality. At the same time products are
required to be environmentally conscious. Therefore it is important to
achieve appropriate product reliability with minimum resource
consumption. In the total product lifecycle there exist various kinds
of disturbances which may deteriorate product quality and
functionality. A reliability design method is proposed based on
prediction of product behaviour deterioration and its influence on
product functional failure. Effectiveness of the proposed method is
evaluated by mechatronics product design.
|
|
A Risk Mitigation Methodology for New Product and Process Design in Concurrent Engineering Projects
|
|
B. Kayis, G. Arndt (1), M. Zhou, S. Amornsawadwatana
|
|
STC Dn, 56/1/2007, P.167
|
|
Keywords: Product Development, Concurrent Engineering, Design |
Abstract : Based on earlier work on risk quantification, a new risk
mitigation methodology is developed for new product and process design
in concurrent engineering projects. First the most prominent risks in
the product life cycle are identified and quantified. Then five
computational algorithms are developed and used to find feasible
solutions for mitigating these risks: Least-Cost-First,
Highest-Risk-First, Minimum-Cost-Risk-Ratio- First, Random-Search and
a Genetic Algorithm. Based on the available mitigation budget and
strategic objectives of the project the best mitigation strategy is
then recommended to the project managers. Actual financial outcomes of
an industry project were used to successfully validate the
methodology.
|
|
Decoupling Executions in Navigating Manufacturing Processes for Shortening Lead Time and Its Implementation to an Unmanned Machine Shop
|
|
M. Nakao (2), N. Kobayashi, K. Hamada, T. Totsuka, S. Yamada
|
|
STC Dn, 56/1/2007, P.171
|
|
Keywords: Scheduling, Decision making, Mold |
Abstract : A new navigation method that decouples manufacturing
processes of tailor-made products has been developed for shortening
lead time. Axiomatic Design expresses manufacturing processes with two
design equations; one with functional requirement (FR) of
'defining process' and design parameter (DP) of
'decisions in process,' and the other with FR of
'predicting completion time of product' and DP of
'priority of product.' Once formulated, decoupling the
system with the rules of 'No feedback' and 'No moving
up' effectively shortens lead time. Applying the navigation
methodology to a real unmanned machine shop of molds, eventually
shortened it from 44 to 7.7 days.
|
|
Knowledge Management in Process Planning
|
|
B. Denkena (1), M. Shpitalni (1), P. Kowalski, G. Molcho, Y. Zipori
|
|
STC Dn, 56/1/2007, P.175
|
|
Keywords: CAPP, Abrasive processes, Knowledge management |
Abstract : Considerable research and development efforts have been
devoted to Computer Aided Process Planning (CAPP). Nevertheless,
because the CAPP problem is complex and is characterized by many
interdependent technical and business parameters and variables, no
viable off-the-shelf solution is yet available that can be easily or
widely implemented in industry. This paper presents an overview of the
CAPP field and describes a holistic component manufacturing process
planning model based on an integrated approach combining technological
and business considerations. The model was derived based on available
literature, an overview of the state-of-the-art in Digital
Manufacturing, Product Lifecycle Management (PLM) and CAPP solution
providers, and a survey of Small Medium Enterprise (SME)
manufacturers. This model will form the basis for developing improved
decision support and knowledge management capabilities to enhance
available CAPP solutions.
|
|
Impact of Argumentative Negotiation on Collaborative Engineering
|
|
Y. Jin, M. Geslin, S.C-Y. Lu (1)
|
|
STC Dn, 56/1/2007, P.181
|
|
Keywords: Design, Decision Making, Negotiation |
Abstract : Engineering of complex systems involves multiple
disciplinary design teams with diversified skills. The team members
must work together to make joint decisions, but are often faced with
difficulties when trying to reach agreements. Negotiation has been
studied as a method for facilitating information exchange, mutual
understanding, and joint decision-making. In our previous work, we
introduced an argumentative negotiation model to support collaborative
engineering. In this paper, we present an experiment study that was
conducted to assess the impact of this negotiation support system on
the process and the outcome of collaborative design. The results of
the experiment have demonstrated the positive effects of the approach.
|
|
Complexity of Multi-Disciplinary Design
|
|
T. Tomiyama (2), V. D'Amelio, J. Urbanic, W. ElMaraghy (1)
|
|
STC Dn, 56/1/2007, P.185
|
|
Keywords: Design, Knowledge, Complexity Management |
Abstract : Modern products such as mechatronics machines are
increasingly becoming multi-disciplinary. This phenomenon is amplified
when considering a system composed of mechatronic elements. This paper
first introduces two different types of complexity: (i) complexity by
design and (ii) the intrinsic complexity of multi-disciplinarity, from
the viewpoint of knowledge structure. These two types of complexity do
not just make product development processes difficult, but cause
design failures through undesired and unpredictable coupling of design
parameters. Then, the paper illustrates two multi-disciplinary design
cases and analyzes their knowledge structure to clarify how and why
these couplings happened.
|
STC E |
|
New Developments in Laser Sintering of Diamond Cutting Disks
|
|
V. Kovalenko (2), L. Golovko, J. Meijer (1), M. Anyakin
|
|
STC E, 56/1/2007, P.189
|
|
Keywords: laser, SLS, diamond tool |
Abstract : The analysis of techniques and problems in the fabrication
of cutting tools based on super hard composites results in a solution
by the application of lasers. The results of systematic study of
diamond composites sintering with laser radiation are discussed. A
mathematical modeling of the heat transfer process at high speed laser
beam scanning has resulted in connections between working conditions
and irradiated material characteristics. Experimental results of the
influence of the laser parameters on the diamonds strength, the
reliability of their fixing and composite materials structure changes
are demonstrated. The possibilities to use new bonding materials based
both on iron or other metals to improve the workability of the cutting
tools are discussed.
|
|
Striation-free Laser Cutting of Mild Steel Sheets
|
|
L. Li (2), M. Sobih, P.L. Crouse
|
|
STC E, 56/1/2007, P.193
|
|
Keywords: Laser cutting, roughness, quality |
Abstract : Striation, i.e. periodic lines appearing on the cut
surface, is one of the most important quality factors in laser
cutting. It affects the surface roughness, appearances and geometry
precision of laser cut products. Despite various efforts over the last
30 years to understand striation formation mechanisms and to optimise
laser parameters, no reported work has so far shown striation-free
cutting. This paper reports an investigation into achieving
striation-free laser cutting of EN43 mild steel sheets of 2 mm
thickness. A 1 kW single mode fibre laser was used in this
work. Specific operating conditions have been determined which enable
high-speed, striation-free laser cutting. A theoretical model is
proposed to predict the critical cutting speed at which striation-free
cutting occurs. It is also observed that at cutting speeds above the
critical cutting speed, striation reappears and surface roughness
increases with the cutting speed, a phenomenon not observed before.
|
|
Interaction between Electrical Arc and Nd: YAG Laser Radiation
|
|
U. Stute (3), R. Kling, J. Hermsdorf / H. Trumpold (1)
|
|
STC E, 56/1/2007, P.197
|
|
Keywords: Laser beam machining (LBM), Welding, Electrical discharge machining (EDM) |
Abstract : This paper describes the stabilization and guidance of
plasma plumes through the interaction with low power laser
radiation. The stabilization and guidance have been found to be
governed by several physical effects. One effect is the localized rise
of electrical conductivity. As the laser provides a channel of
increased conductivity an alignment and a stabilisation of the
electrical arc can be obtained. This feature can be exploited to
achieve more efficient and flexible plasma processes. Investigations
on plasma guidance with respect to different laser wavelengths and
interaction modes will be presented by means of example in welding and
EDM.
|
|
An Experimental Study on Laser Cutting Mechanisms of Polycrystalline Diamond Compacts
|
|
G.F. Zhang, B. Zhang (2), Z.H. Deng, J.F. Cheng
|
|
STC E, 56/1/2007, P.201
|
|
Keywords: Laser Cutting, PDC, Heat-Affected Zone |
Abstract : The objective of this study is to experimentally
investigate the cutting mechanisms of polycrystalline diamond compacts
(PDC) using two different lasers: (a) a near infrared Nd:YAG laser
(Neodymium-doped Yttrium Aluminum Garnet) of 1064 nm wavelength and
100 microsec pulse width; and (b) a green light KTP (Potassium Titanyl
Phosphate) /Nd:YAG laser of 532 nm wavelength and 120 ns pulse
width. To realize the objective, the study applies polishing, lapping
and etching processes to the cut-surfaces of the PDC samples. It
further observes and analyzes the processed cut-surfaces with scanning
electron microscopy (SEM) and Raman spectroscopy. A discussion is
provided to reveal the underlying physics of the laser cutting
mechanisms, and a conclusion is drawn based on the outcomes from the
experimental investigation and the discussion.
|
|
Selective Laser Sintering of PEEK
|
|
M. Schmidt (3), D. Pohle, T. Rechtenwald / M.Geiger (1)
|
|
STC E, 56/1/2007, P.205
|
|
Keywords: Selective Laser Sintering (SLS), Biomedical, Polymer |
Abstract : Polyetheretherketone (PEEK) is a good choice especially for
manufacturing medical instruments or implants. These parts are
typically produced by conventional manufacturing methods, like
injection moulding. Selective Laser Sintering (SLS) could offer more
flexibility. It enables the direct manufacturing of products with
complex geometries. Although SLS of polymers like polyamide or
polystyrene is a standard industrial process already, laser sintering
of PEEK remains a challenge. This article will show for SLS of PEEK
the necessary adaptations in systems technology and material
modifications and discuss a step-by-step process
implementation. Process boundaries are shown concerning temperature
and energy input. The high influence of porosity, which could be
varied from zero to 15 %, on mechanical properties is shown.
|
|
Layered Laser Vaporization of PMMA Manufacturing 3D Mould Cavities
|
|
L. Romoli, G. Tantussi, G. Dini (1)
|
|
STC E, 56/1/2007, P.209
|
|
Keywords: LBM, Mould, PMMA |
Abstract : This paper deals with an innovative technique concerning
CO2 laser machining in order to create 3D cavities to be used as
moulds for the casting of polymer resins, vaporizing PMMA layer by
layer. The removal of a single layer is achieved using multiple
overlapping straight grooves. The groove profile (depth and width) has
been predicted by theoretical models which investigate the influence
of cutting sequence, number of passes, laser beam scanning speed and
radiant flux. The removal depth varies proportionally with the number
of layers, while the surface roughness, influenced by the grooves
spacing and the orientation of the scanning direction between
successive layers, cannot be decreased under a minimum value.
|
|
Study on Nano EDM Using Capacity Coupled Pulse Generator
|
|
M. Kunieda (2), A. Hayasaka, X. D. Yang, S. Sano, I. Araie
|
|
STC E, 56/1/2007, P.213
|
|
Keywords: Electrical discharge machining, Micromachining, Miniaturization |
Abstract : This paper describes the development of a pulse generator
for nano EDM using a capacity coupling method. To obtain discharge
craters of nanometer diameter, a pulse generator was coupled to the
tool electrode by a capacitor. Since the influence of the stray
capacitance in the electric feeders can be eliminated, the discharge
energy can be minimized to accomplish nano EDM. This method also
allows non-contact feeding of electric current to the rotating
spindle, minimizing the run-out of the tool electrode. To control the
gap width, the gap voltage was also measured using the capacity
coupling method.
|
|
Understanding Dielectric Breakdown and Related Tool Wear Characteristics in Nanoscale Electro-Machining Process
|
|
K.R. Virwani, A.P. Malshe (2), K.P. Rajurkar (1)
|
|
STC E, 56/1/2007, P.217
|
|
Keywords: Electrical discharge machining; scanning tunneling microscope; nanomanufacturing |
Abstract : To address the need to produce sub-50 nm scale features for
manufacturing of nano / bio devices and systems, a nanoscale
electro-machining (nano-EM) process is being studied. This paper
reports unique field induced effects on a tungsten tool. During
machining, the tungsten atoms leave the active tool tip in the form of
clusters. Upon machining, the tool tip end radius was sharper (~20nm
after in comparison with ~35nm before). The tool surface was
chemically modified to a nanocrystalline matrix of tungsten oxide and
tungsten carbide. The tool sharpening and the formation of the
nanocrystalline matrix are expected to prolong the tool life in the
nano-EM process in a manufacturing environment.
|
|
Rotating Curvilinear Tools for EDM of Polygonal Shapes with Sharp Corners
|
|
Y. Ziada, p. Koshy (2)
|
|
STC E, 56/1/2007, P.221
|
|
Keywords: Electrical discharge machining (EDM), Kinematic, Reuleaux Triangle |
Abstract : Flushing of the inter-electrode gap is of critical
importance in the performance of electrical discharge sinking
operations. When the provision of flushing holes in the tool or the
workpiece is impractical, effective flushing is best realized by
inducing a relative motion between the electrodes. This paper relates
to a novel application inspired by the kinematics of a Reuleaux
Triangle that facilitates flushing through synchronous orbiting of a
rotating curvilinear tool. This innovative scheme enables the
machining of regular as well as non-regular polygonal shapes with
sharp corners. Experimental results from implementing this concept on
a 4-axis CNC EDM machine tool are presented.
|
|
Development of Technology and Strategies for the Machining of Ceramic Components by Sinking and Milling EDM
|
|
B. Lauwers (2), J.P. Kruth (1), K. Brans
|
|
STC E, 56/1/2007, P.225
|
|
Keywords: Electrical Discharge Machining (EDM), Ceramic, Milling EDM |
Abstract : This paper investigates the manufacturability of B4C, SiC,
Si3N4-TiN by milling EDM and the performance of it has been compared
to conventional sinking EDM. It is shown that due to the good flushing
conditions, milling EDM performs well, even for the machining of
ceramic materials with a rather low electrical conductivity (B4C,
SiC). Because the used milling EDM technique removes material in a
layer by layer fashion (2D-machining), a new strategy for the
machining of complex 3D-shapes in ceramic material has been
developed. It consists of a milling EDM pre-machining step, followed
by one or more finishing sinking EDM steps. The developed strategy has
been validated on an industrial example and compared to a pure sinking
EDM strategy. Time reductions of more than 50% were obtained.
|
|
Self-Sharpening of Thin Tungsten Electrode in Single, High-Current Discharge: its Dynamics and Mechanism
|
|
Y. Ito, R. Tanabe, N. Mohri (1)
|
|
STC E, 56/1/2007, P.229
|
|
Keywords: EDM, Electrode, time-resolved observation |
Abstract : Self-sharpening of a thin tungsten electrode occurs in
single, high-current discharge. This phenomenon has been observed with
a custom-made, high-speed imaging system. The system allowed us to
take one hundred images of the electrode shape during and after the
discharge with 16 μs intervals. The following self-sharpening
mechanism has been proposed based on observations: (1) During the
discharge, when the melt front descends towards the axis of the
electrode, while the melt forms a sphere and moves along it due to the
surface tension. (2) The melt continues moving even after the
discharge, revealing a needle-shaped un-melted part and then
solidifies. Detailed studies of discharge conditions to the diameter
of the needle-shape formed by the process have been carried
out. Results supporting the proposed mechanism are obtained.
|
|
Electrical Discharge Machining of Carbon Nanofiber for Uniform Field Emission
|
|
B.H. Kim, J.G. Ok, Y.H. Kim, C.N. Chu (2)
|
|
STC E, 56/1/2007, P.233
|
|
Keywords: Electrical discharge machining (EDM), Nano technology, Carbon |
Abstract : Electrical discharging machining (EDM) of carbon nano fiber
(CNF) is introduced. CNF has been investigated as an emitter for field
emission display (FED). For the uniform field emission, uneven CNFs
need to be machined to uniform height. For the planarization of CNFs,
EDM was used. EDM was conducted in air, unlike conventional EDM, to
prevent the contamination of CNFs. For the uniformity of the machined
surface, machining characteristics were investigated with applying
different capacitance and voltage. With this method, the uniformity of
field emission of CNFs was improved. Micro machining of CNFs was also
studied.
|
|
Complex Process Chains for Manufacturing of Invisible Displays Integrated in Bulk Metal Panels
|
|
H.N. Hansen (2), J.P. Prichystal, p. Moller, H.H. Bladt
|
|
STC E, 56/1/2007, P.237
|
|
Keywords: Laser micro machining, Electro chemical machining, Integrated displays |
Abstract : Information displays that are invisible in the inactive
state, and concealed in transparent or semi-transparent materials such
as plastic or glass, are commercially available. However, if displays
were to be invisibly integrated in bulk metal panels, very few known
solutions exist. This has to do with the fact that very thin (20-50
nm) metal layers are required for the light to penetrate. This paper
describes the realisation of displays integrated in bulk metal panels
through the development and optimisation of complex process chains
involving laser micromachining, micro electrochemical machining and
selective anodising. An extensive experimental investigation of the
single processes as well as their sequential combination is reported,
and the capabilities of the different process chains are demonstrated.
|
|
Micro Wire Electrochemical Cutting by Using In Situ Fabricated Wire Electrode
|
|
D. Zhu (2), K. Wang, N.S. Qu
|
|
STC E, 56/1/2007, P.241
|
|
Keywords: Micromachining, ECM, Wire |
Abstract : This study develops a micro wire electrochemical cutting
process. Because of no electrode wear in this process a very thin
metal wire can be used as the wire electrode. The tungsten wire
electrode with the diameter of 5µm is electrochemically in situ
fabricated for the production of micro structures with the slit width
of less than 20µm. Effects of process parameters on the wire
diameter in the wire etching and on the gap variation in the
electrochemical cutting have been studied theoretically and
experimentally. Many complex micro metal parts with structures of
several ten micrometers have been obtained.
|
|
Fabrication of High Thermal Conductivity Carbon Nanotube Arrays by Self Assembled Fe3O4 particles
|
|
K. Zhang, M.M.F. Yuen, J.H. Gao, B. Xu / M.M. Tseng (1)
|
|
STC E, 56/1/2007, P.245
|
|
Keywords: Chemical vapor deposition (CVD), Carbon nanotube, Thermal |
Abstract : The outstanding properties of carbon nanotubes (CNTs) have
induced widespread interest in researches and applications. A new
approach of fabricating vertically aligned CNT arrays with good CNT
size and distribution control, and enhanced substrate attachment is
under development. This technique includes fabrication and size tuning
of Fe3O4 nanoparticles, buffer layer preparation on Si substrates,
self assembly of Fe3O4 nanoparticles on substrates, CNT synthesis by
thermal CVD with optimized operation parameters. One application of
the synthesized CNT arrays is serving as thermal interface material to
meet the thermal management challenge in high power microelectronic
packages. The thermal performance of the synthesized CNT arrays was
evaluated.
|
STC F |
|
Modelling of the Forming Limit Band -A new Method to Increase the Robustness in the Simulation of Sheet Metal Forming Processes
|
|
D. Banabic (2), M. Vos
|
|
STC F, 56/1/2007, P.249
|
|
Keywords: Sheet metal, Computer Aided Manufacturing, Forming |
Abstract : Forming Limit Curves are valid for one particular material
alloy, temper and gauge combination. However material properties vary
from batch to batch due to variation in the production process. For
there a single Forming Limit Curve can not be an exact description of
the forming limit. Several researchers have proposed a more general
concept, namely the Forming Limit Band (FLB) as a region covering the
entire dispersion of the Forming Limit Curves. A Forming Limit Band
can successfully be predicted using the normal statistical
distribution found in different production lots, of the yield
stresses. Until now, the study of the dispersion was only
experimental. Using the FORM-CERT software the influence of the
different material parameters on the FLC has been studied. Using the
normal distribution of mechanical properties the plus and minus
3-Sigma limits are used to determine the Upper- and the Lower FLC. The
region between these two curves represents the Forming Limit Band. The
paper presents for the first time the numeric modelling of the FLB
concept. This method is illustrated on the AA 6111-T43 aluminum alloy.
|
|
Buckling of Sheet Metals in Contact with Tool Surfaces
|
|
J. Cao, S.H. Cheng, H.P. Wang, C.T. Wang / B.F. von Turkovich (1)
|
|
STC F, 56/1/2007, P.253
|
|
Keywords: Sheet metal, Stamping, Buckling |
Abstract : The buckling point detected at the Yoshida Buckling Test is
at an extremely low strain level, which does not reflect the reality
observed in stamping of complex parts. A new buckling test,
"Contact Buckling Test", is proposed here with the thought
that the delay of buckling in reality is due to the existence of sheet
curvature and the contact support provided by tooling. Interesting
buckling phenomena have been observed for both aluminum and steel
sheets, including oil canning, buckling at the loading stage, and
buckling at unloading. The fundamentals of these different buckling
phenomena will be explained through a stress-based wrinkling predictor
developed by the authors.
|
|
Paddle Forming: a Novel Class of Sheet Metal Forming Processes
|
|
J.M. Allwood (2), D.R. Shouler
|
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STC F, 56/1/2007, P.257
|
|
Keywords: Forming, Sheet metal, Formability |
Abstract : A novel class of 'paddle forming' processes for
forming pronounced features within sheet metal components is
presented. The processes are incremental in nature and are
characterised by having contact between the tool and the workpiece
along a short line segment. The processes lead to high
through-thickness shear strains, which have been shown to increase the
possible deformation before ductile instability occurs. Paddle forming
tools, which are cheap and simple to manufacture, can be applied to
the faces or edges of sheets, tubes and disks. Four example processes
are demonstrated, each showing high deformation and pronounced
through-thickness shear strain.
|
|
An Approach to Modelling the Forming Process of Sheet Metal-Polymer Composites
|
|
P.F. Bariani (1), S. Bruschi (2), A. Ghiotti, G. Lucchetta
|
|
STC F, 56/1/2007, P.261
|
|
Keywords: Sheet Metal Forming, Polymer Injection Forming, Multi-Physics Modelling |
Abstract : Polymer Injection Forming (PIF) and
Polymer Injection-Compression Forming (PICF) are new manufacturing
technologies for sheet metal-polymer macro-composites, which result
from the combination of injection moulding and sheet metal forming. In
these processes, a metal blank is formed inside an injection mould by
using the pressure of the molten polymer that, after cooling,
permanently bonds to the metal sheet creating a fully finished product
in only one production step. This paper presents a calibrated
multi-physics numerical model of the processes that proves to be
suitable to investigate the mutual metal-polymer interactions and to
provide a reliable tool in designing the process as well as its
control.
|
|
Mechanism of Springback-Free Bending of High-Strength Steel Sheets under Warm Forming Conditions
|
|
J. Yanagimoto (2), K. Oyamada
|
|
STC F, 56/1/2007, P.265
|
|
Keywords: Sheet metal, Springback, Warm sheet forming |
Abstract : Tensile loading-unloading tests of high-strength steel
sheets in an elevated temperature range are conducted using a 100kN
servo-controlled hydraulic dynamic fatigue testing machine, aiming at
clarifying the mechanism of the springback-free phenomenon occurring
in warm sheet forming. From stress-strain curves obtained by the
tests, it is found that the abrupt decrease in the springback of
formed steel sheets at approximately 750K in isothermal v-bending
tests is mainly caused by high-temperature transient creep
deformation. Also, from the results obtained by the isothermal
v-bending test, bending-unbending deformation observed at temperatures
higher than 750K, as a result of high-temperature creep, was found to
have a secondary effect in the springback-free phenomenon.
|
|
Design of Hot Stamping Tools with Cooling System
|
|
H. Hoffmann (2), H. So, H. Steinbeiss
|
|
STC F, 56/1/2007, P.269
|
|
Keywords: Hot Stamping, Finite element method (FEM), Optimization |
Abstract : Hot stamping with high strength steel is becoming more
popular in automotive industry. In hot stamping, blanks are hot formed
and press hardened in a water-cooled tool to achieve high
strength. Hence, design of the tool with necessary cooling
significantly influences the final properties of the blank and the
process time. In this paper a new method based on systematic
optimization to design cooling ducts in tool is introduced. The
optimization procedure was coupled with FE analysis and a specific
evolutionary algorithm. Through this procedure each tool component was
separately optimized. Subsequently, the hot stamping process was
simulated both thermally and thermo-mechanically with the combination
of optimized solutions.
|
|
Laser Assisted Incremental Forming: Formability and Accuracy Improvement
|
|
J.R. Duflou (2), B. Callebaut, J. Verbert, H. De Baerdemaeker
|
|
STC F, 56/1/2007, P.273
|
|
Keywords: Forming, Laser, Incremental forming |
Abstract : Single point incremental forming accuracy suffers from
contradictory material requirements: while a low yield strength and
low hardening coefficient are favourable in terms of limiting process
forces and springback, they also result in excessive, unwanted plastic
deformation in zones bordering processed areas. Dynamic, localised
heat input, for example through radiation of the tool contact area by
means of a laser beam, allows to differentiate material properties in
time and space. Experimental results demonstrate that this process
variant results in reduced process forces, improved dimensional
accuracy and increased formability for a range of materials. Initial
results also indicate that residual stresses can be significantly
reduced by means of the dynamic heating system that was developed.
|
|
Forming Limit Curves in Single Point Incremental Forming
|
|
M. Ham, J. Jeswiet (1)
|
|
STC F, 56/1/2007, P.277
|
|
Keywords: Forming; Sheet metal; Incremental Forming |
Abstract : New experimental data is presented on Forming Limits in
Single Point Incremental Forming (SPIF), which is a sheet metal
forming process which does not require dies. A Box-Behnken Design of
Experiment is used to develop the experimental plan and analyze
data. In former work, the most critical factors affecting Single Point
Incremental Forming were found to be material type, material
thickness, formed shape, tool size, and incremental step size. In this
experimental work, new results are presented as graphical response
surfaces which show the forming limit for all the critical factors
listed previously. In addition, forming limits are presented in terms
of Forming Limit Diagrams.
|
|
Deformation Machining - A New Hybrid Process
|
|
S. Smith (1), B. Woody, J. Ziegert, Y. Huang
|
|
STC F, 56/1/2007, P.281
|
|
Keywords: Manufacturing, Deformation, Machining |
Abstract : This paper describes a novel hybrid process, Deformation
Machining, that combines two emerging manufacturing processes --
machining of thin structures and single point incremental
forming. This hybrid process enables the creation of structures that
have geometries that would be difficult or impossible to create using
any other processes. A feasibility study has been conducted exploring
the toolpath planning and deformation force data was
collected. Because the forming operations occur on sheet-like material
made by machining rather than rolling, we have conducted experiments
testing the formability of machined sheet. Preliminary results are
encouraging, and point to a broad range of industrial applications for
this process.
|
|
Cold Deep Drawing of Commercial Magnesium Alloy Sheets
|
|
K. Mori (2), H. Tsuji
|
|
STC F, 56/1/2007, P.285
|
|
Keywords: Magnesium, Sheet, Cold Deep Drawing |
Abstract : A cold deep drawing process for commercial AZ31 magnesium
alloy sheets was developed. The commercial sheets were successfully
formed into circular cups at room temperature by optimising the
annealing temperature of the sheets, i.e. a limiting drawing ratio of
1.75 was attained for an annealing temperature of 500 ºC. The
increases in elongation, n-value and r-value, and the decrease in flow
stress effective in the improvement of drawability were obtained for
the annealing. The apparatus for cold deep drawing without heating
becomes much simpler than that for the conventional warm deep
drawing. The effects of the lubricant, the clearance between the die
and the punch and the corner radius of the punch on the drawability
were examined. The limiting drawing ratio was increased by applying
force onto the edge of a blank through the die corner. In addition,
cold deep drawing of magnesium alloy square cups was performed. It was
found that comparatively shallow magnesium alloy cups are
satisfactorily formed at room temperature without heating.
|
|
Investigation of Post-Superplastic Forming Properties of AZ31 Magnesium Alloy
|
|
M.K. Khraisheh, F.K. Abu-Farha, K.J. Weinmann (1)
|
|
STC F, 56/1/2007, P.289
|
|
Keywords: Deformation, Magnesium, Superplastic Forming |
Abstract : In the metal forming industry, most of the efforts are
directed towards materials and process development, with little
attention paid to the properties of the formed components. In
Superplastic Forming (SPF), the issue of post-forming properties is
particularly important because of the large plastic deformation,
significant microstructural changes, and exposure to elevated
temperatures for prolonged periods of time. In this work, a detailed
experimental study on the mechanical and microstructural properties of
superplastically-formed AZ31 magnesium alloy is presented. The results
clearly show the necessity to integrate post-superplastic forming
analysis with material and process development for SPF optimization.
|
|
Fracture of Magnesium Alloy in Cold Forging
|
|
R. Matsumoto, T. Kubo, K. Osakada (1)
|
|
STC F, 56/1/2007, P.293
|
|
Keywords: Magnesium, Forging, Fracture |
Abstract : To clarify the forming limit of magnesium alloy in cold
forging, workability of magnesium alloy is examined for upsetting and
backward extrusion at temperatures below 523K. In the upsettability
test, sudden fracture by crack propagation occurs at a small
equivalent strain of about 0.15. On the other hand, in cold backward
extrusion with a conical punch, the local strain can reach a very
large value, 3.0 or greater, without fracture. To explain the
experimental results, the mechanism of fracturing is discussed on the
basis of strain localization, and a fracture criterion of magnesium
alloy in cold forging is put forward.
|
|
Lubrication Mechanism in Hot Rolling by Newly Developed Simulation Testing Machine
|
|
A. Azushima (2), W.D. Xue, Y. Yoshida
|
|
STC F, 56/1/2007, P.297
|
|
Keywords: Friction, Lubrication, Rolling |
Abstract : In order to create the ultra-fine grained steels, the hot
rolling with a high rolling force is necessary, so that the
tribological problems such as the improvement of the decrease of the
rolling force, the prevention of the friction pick up and so on. One
attempt for the solution of problems is to develop innovative hot
rolling oils. Consequently, in order to understand the lubrication
mechanism in hot rolling, it is desired that the data of the
coefficient of friction under the wide range of tribological
conditions are obtained. In this paper, the simulation testing machine
in the laboratory for hot rolling is developed and the coefficient of
friction are measured. The lubrication mechanism in hot rolling is
investigated.
|
|
Contact Conditions in Skin-pass Rolling
|
|
H. Kijima, N. Bay (1)
|
|
STC F, 56/1/2007, P.301
|
|
Keywords: Rolling, Friction, Skin-pass rolling |
Abstract : The special contact conditions in skin-pass rolling of
steel strip is analysed by studying plane strain upsetting of thin
sheet with low reduction applying long narrow tools and dry friction
conditions. An extended sticking region is estimated by an
elasto-plastic FEM analysis of the plane strain upsetting. This
sticking region causes a highly inhomogeneous elasto-plastic
deformation with large influence of work-hardening and friction. A
numerical analysis of skin-pass rolling shows the same contact
conditions, i.e. an extended sticking region around the center of the
contact zone. The calculated size of the sticking region with varying
contact length and pressure/reduction is experimentally verified by
plane strain upsetting tests measuring the local surface deformation
of the work pieces after unloading.
|
|
Improved Process Design and Quality for Gear Manufacturing with Flat and Round Rolling
|
|
R. Neugebauer (1), M. Putz (3), U. Hellfritzsch
|
|
STC F, 56/1/2007, P.307
|
|
Keywords: Forming, Rolling, Gear |
Abstract : This paper describes a new method and its results in the
roll-forming of gears that has significantly surpassed the
conventional limits known till now. The method describes the rolling
process and an alternative pitch design of forming tools. A model was
created to analyze rolling processes which determined that in contrast
to flat rolling tools, round tools need additional kinematic
compensation during diameter-related variable pitch forming
processes. This presented method shows up to a 50 % improvement in
pitch accuracy and the ability to roll high teeth gears (up to 10 mm
in height and a toothheight-coefficient larger than 2).
|
|
Implementing a high accuracy Multi-Mesh Method for incremental Bulk Metal Forming
|
|
G. Hirt, R. Kopp (1), O. Hofmann, M. Franzke, G. Barton
|
|
STC F, 56/1/2007, P.313
|
|
Keywords: Finite element method, Forming, Multi-mesh method |
Abstract : The demand for the simulation of incremental bulk forming
processes is high. However, the computation times for such simulations
are still unsatisfactorily long and thus, their application is
deterred. To accelerate the simulations, a multi-mesh algorithm was
implemented in the Finite-Element simulation package
PEP&LARSTRAN/Shape. This method uses a FE mesh which is fine in
the deformation zone and coarse in the remaining areas. A second mesh,
fine over the entire volume, is used to store computed values and to
minimize the loss of accuracy. The method was tested on an open die
forging process and adapted for ring rolling. This paper describes the
latest further developments of the method in [1], for instance tool
kinematics, remeshing and data transfer and compares its results to
conventional models, thereby showing its performance and accuracy.
|
|
Simulation-Based Analysis of Composite Extrusion Processes
|
|
M. Schikorra, M. Kleiner (1)
|
|
STC F, 56/1/2007, P.317
|
|
Keywords: Finite element method, Extrusion, Composite |
Abstract : The attempt to combine the excellent mechanical properties
of composite materials with the great economic benefit of conventional
extrusion of lightweight profiles has led to the development of an
extrusion process for standard EN-AW 6060 billets in compound with
endless wires or fiber materials. To comprehend the gen-eral
conditions during composite formation, thermo-mechanically coupled
Finite Element Models based on Lagrangian and Eulerian formulations
have been set up to analyze the mechanical boundary conditions for
composite formation and the influence on the material flowing during
the extrusion process. The three-dimensional models provide insights
on the development of stresses in the base as well as reinforcement
material, which helps to find dominating process parameters to prevent
the reinforcement from experimen-tally determined cracking.
|
|
Investigation of Laser Heating in Microforming Applying Sapphire Tools
|
|
M. Terzi, J.P. Wulfsberg / D. Schmoeckel (1)
|
|
STC F, 56/1/2007, P.321
|
|
Keywords: Laser, Forming, miniaturization |
Abstract : The application of metal forming technologies to the
production of metallic micro parts is limited by problems arising from
size effects related to small dimensions. An approach to solve these
problems is the laser-assistance of the micro forming process to
benefit from e.g. the growing influence of thermodynamic
aspects. Experimental investigations were carried out to determine the
workpiece temperature by varying laser power at constant heating
time. This is a substantial factor for the laser-assisted micro
forming process design. Results from a numerical analysis using FEM
techniques were compared with the ones from the test
series. Furthermore micro forming investigations were made showing a
dependence of the material micro structure from tool structure size
and laser power.
|
STC G |
|
The Use of the Size Effect in Grinding for Work-hardening
|
|
C. Heinzel, N. Bleil / J. Peters (1)
|
|
STC G, 56/1/2007, P.327
|
|
Keywords: Grinding, Surface integrity, Residual stress |
Abstract : This paper shows the possibility of using the size effect
of the specific grinding energy for a targeted surface layer
work-hardening of metal parts. The research includes the combination
of abrasive material removal and plastic deformation in a single
grinding step. Therefore high specific energy values are needed and
thermal effects counteracting the work-hardening have to be
minimised. This can be achieved by low cutting speeds in combination
with low depths of cut. The new approach results in an in-process
work-hardening of the surface layer, which was found to lead to higher
hardness, a compressive residual stress state, and higher wear
resistance.
|
|
In-Process Identification of Material-Properties
|
|
N.J. Kramer / K.G. Guenther (1)
|
|
STC G, 56/1/2007, P.331
|
|
Keywords: Grinding, In-Process, Identification |
Abstract : An ever-increasing demand for light-weighted
high-performance parts calls for locally adapted material
properties. This is achieved by joining several materials in one part
featuring common functional surfaces which have to be machined
afterwards. Different materials provoke different material removal
mechanisms which influence tool wear, cutting forces and surface
properties. Although overall process optimization is possible,
individual cutting parameters for each material are favorable. To
introduce adapted parameters, in-process identification of the
machined material is needed. Acoustic emission signals are used in
grinding of steel/ceramic compounds to identify the machined material
in-process. Unconditioned signals are recorded and transferred into
the frequency range. By weighting and comparing material specific
frequency ranges, the machined material is identified independently of
the chosen cutting conditions.
|
|
Profiled Superabrasive Grinding Wheels for the Machining of a Nickel Based Superalloy
|
|
D.K. Aspinwall (2), S.L. Soo, D.T. Curtis, A.L. Mantle (3)
|
|
STC G, 56/1/2007, P.335
|
|
Keywords: Grinding, Nickel, Cubic boron nitride (CBN) |
Abstract : Machining data are presented for small diameter, profiled
(fir tree root form), single layer/electroplated CBN (B46, B76 and 91)
and diamond (D46) grinding wheels, when cutting Udimet 720. Spindles
operating at 60,000 and 90,000rpm were employed, with a synthetic
polyalphaolefine (PAO) oil based fluid in a down grinding mode on
single sided specimens. Operating parameters were selected to reflect
finishing conditions. Measured tool wear was lower for CBN grit as
compared to diamond however workpiece roughness was lower with Ra
approaching 0.75µm when using D46 wheels. Higher rotational
speed produced lower grinding wheel wear. No workpiece burning was
observed irrespective of grit type at the conditions tested.
|
|
Factors Affecting Grinding Performance with Electroplated CBN Wheels
|
|
R.P. Upadhyaya (3), J.H. Fiecoat (3) / S. Malkin (1)
|
|
STC G, 56/1/2007, P.339
|
|
Keywords: Grinding, Cubic Boron Nitride (CBN), Wear |
Abstract : An experimental investigation was conducted to evaluate the
effect of CBN crystal characteristics and plating thickness on the
performance of electroplated CBN wheels. Wheels containing tougher CBN
crystals generally exhibited less wear and a higher G-ratio, and also
required less power. Furthermore, contrary to expectations, less wear
and higher G-ratio were also obtained for wheels with a thinner layer
of nickel plating despite an increased tendency for large-scale
crystal loss. This would indicate that the overall wheel wear depends
more on crystal exposure than on active grain density, which could
facilitate chip removal and grinding fluid access. Extended grinding
tests up to wheel failure ascertain the improved grinding performance
with tougher crystals and thinner electroplated layers.
|
|
Power and Wheel Wear for Grinding Nickel Alloy with Plated CBN Wheels
|
|
C. Guo (3), Z. Shi, H. Attia (2), D. McIntosh (3)
|
|
STC G, 56/1/2007, P.343
|
|
Keywords: Grinding, CBN, Nickel alloy |
Abstract : Electroplated CBN grinding wheels are manufactured with a
single layer of abrasive grains. The grinding performance of these
plated wheels changes significantly as the wheel wears down. The
present investigation was undertaken to understand the transient
grinding behavior with electroplated CBN wheels in order to provide a
logical basis for process control. In this paper, particular attention
is directed to the effect of wheel wear and operating parameters on
grinding of a nickel alloy. Wheels were worn to various stages and
then used to perform grinding tests under various grinding conditions
to measure grinding forces and power and to produce ground
specimens. Based on models for grinding with conventional aluminum
oxide wheels, a power model for grinding of a nickel alloy with plated
CBN wheels was established and validated. Microscopic observations of
the ground specimens reveal that thermal damage in the form of a White
Etch Layer (WEL) appears only when grinding with a worn wheel under
conditions that lead to high temperatures.
|
|
Intelligent Centerless Grinding: Global Solution for Process Instabilities and Optimal Cycle Design
|
|
I. Gallego (3) / R. Bueno (1)
|
|
STC G, 56/1/2007, P.347
|
|
Keywords: Centerless Grinding, Productivity, Simulation |
Abstract : Centerless grinding productivity is largely limited by
three types of instabilities: chatter, geometric lobing and workpiece
rotation problems. Regardless of its negative effect in manufacturing
plants, no functional tool has been developed to set up the process,
because it involves the simultaneous resolution of several coupled
problems. In this paper, new simulation techniques are described to
determine instability-free configurations, making it possible to
guarantee that the final workpiece profile is round. With this
information and taking into account other process restrictions, like
system static stiffness and workpiece tolerance, the optimal grinding
cycle is designed. These results have been implemented into an
intelligent tool to assist the application of this research in
industrial environments.
|
|
Grindability of Conventionally Produced and Powder-Metallurgy High-Speed Steel
|
|
J. Badger / J. Webster (1)
|
|
STC G, 56/1/2007, P.353
|
|
Keywords: Grinding, Structure, Machinability |
Abstract : The factors affecting the grindability
of high-speed steel (HSS) were investigated by measuring G-ratio and
power consumption in surface grinding of 18 grades of HSS of different
composition with an aluminium-oxide wheel. The dominant factor
affecting grindability was the size of vanadium carbide. The marked
difference between HSS produced by the conventional method and the
powder-metallurgy method was analyzed. The relationship between power
consumption, G-ratio and grindability was investigated.
|
|
CMP Pad Break-in Time Reduction in Silicon Wafer Polishing
|
|
H.D. Jeong, K.H. Park, K.K. Cho (1)
|
|
STC G, 56/1/2007, P.357
|
|
Keywords: Monitoring, Silicon, Polishing |
Abstract : This paper investigated the correlation between the surface
conditions of the polishing pad and the break-in phenomena during
silicon wafer polishing. The break-in is defined as pad conditioning
to insure first polishing is consistent with second and following
wafer polishing. A piezoelectric force sensor and an infrared (IR)
sensor were installed on a silicon wafer polisher. The signals for
friction force and temperature of the pad surface were measured
simultaneously for monitoring the break-in phenomena during the
polishing process. As a result of monitoring, the pad surface
condition had the most significant effect on the break-in phenomena
than compared to the other polishing parameters. Therefore, the
control of the surface condition of the pad ensures the reduction of
the break-in time during silicon wafer polishing.
|
|
Development of Silica Polyvinyl Alcohol Wheels for Wet Mirror Grinding of Silicon Wafer
|
|
Y. Tani (2), T. Okuyama, S. Murai, Y. Kamimura, H. Sato (1)
|
|
STC G, 56/1/2007, P.361
|
|
Keywords: Grinding, Silicon Wafer, Mirror Finishing |
Abstract : It is strongly desired to develop a cup grinding wheel
which enables mirror finishing of a device wafer on the same machine
after back grinding. Silica wheels have the capability of mirror
finish in a dry condition but there remain serious problems in
flatness and thermal damage to a dicing tape. A new silica wheel which
can be used in a wet condition has been developed. The PVA (polyvinyl
alcohol) was adopted as the bonding agent, by which the absorbent
swell resulted in disturbance of water infiltration to the inside in
cup grinding. A series of experiments show that mirror finishing will
be achieved within 2 minutes. This could not be accomplished utilizing
phenol wheels.
|
STC M |
|
Time Minimum Trajectory Planning of a 2-DOF Translational Parallel Robot for Pick-and-place Operations
|
|
T. Huang (2), P.F. Wang, J.P. Mei, X.M. Zhao, D.G. Chetwynd
|
|
STC M, 56/1/2007, P.365
|
|
Keywords: Parallel Robot, Motion Planning, Pick-and-place |
Abstract : This paper deals with the time-minimum trajectory planning
of a 2-DOF translational parallel robot named the Diamond for rapid
pick-and-place operations. Kinematics and dynamics of the robot are
formulated using a parametric function, allowing the representation of
the input torque and velocity constraints to be converted to those in
terms of the path length. A modified algorithm for achieving the
minimized traversal time is proposed by taking into account the path
jerk limit. Lithium-ion battery sorting using the Diamond robot is
taken as an example to demonstrate the applicability of this approach.
|
|
A Newly Developed Linear Motor-Driven Aerostatic X-Y Planar Motion Table System for Nano-Machining
|
|
H. Shinno (2), H. Yoshioka, K. Taniguchi
|
|
STC M, 56/1/2007, P.369
|
|
Keywords: Table, Ultra-precision, Nano-machining |
Abstract : The importance of nano-machining processes is continually
increasing in a wide range of industries. In particular, the demands
for machining with stable nanometer order accuracy in a wide work area
have recently increased in the electronics and automotive
industries. In order to meet such industrial requirements, it is
necessary to develop an ultraprecision machine tool based on a new
design concept. Therefore, in this study, a novel linear motor-driven
aerostatic planar motion table system was developed for
nano-machining. The results of actual machining tests confirmed that
the developed table system has a remarkable performance.
|
|
Compensation of Axial Vibrations in Ball Screw Drives
|
|
A. Kamalzadeh, K. Erkorkmaz (2)
|
|
STC M, 56/1/2007, P.373
|
|
Keywords: Feed, Drive, Control |
Abstract : This paper presents a precision control strategy for ball
screw drives. Axial vibrations are modeled and actively compensated in
the control law, which enables the realization of high positioning
bandwidth. Lead errors, arising from imperfections of the screw, are
modeled and removed from the loop by offsetting their effect from the
command trajectory and position feedback signals. Effectiveness of the
proposed strategy is demonstrated in high speed tracking experiments
conducted on a ball screw drive, where a linear positioning accuracy
of 2.6 um has been maintained while traversing the axis at 1000 mm/s
feed with 0.5 g acceleration.
|
|
Adaptronic Vibration Damping for Machine Tools
|
|
A. Ast, S. Braun, p. Eberhard, U. Heisel (1)
|
|
STC M, 56/1/2007, P.379
|
|
Keywords: Machine, Vibration, Adaptronic Actuator |
Abstract : A newly designed adaptronic component with a powerful
piezo-stack actuator for active damping of machine vibrations is
presented in this paper. Especially for machine tools with parallel
kinematics, which feature lightweight structures and which are built
in order to obtain high processing speeds, the active damping of
machine vibrations is important to achieve the desired system
performance. Extensive simulation studies with flexible multibody
systems in order to test different control algorithms such as
dissipative control, integrated force feedback or H2/H∞ control
and recent experimental results show the high potential to improve the
system behaviour.
|
|
A New Method for Simulation of Machining Performance by Integrating Finite Element and Multi-body Simulation for Machine Tools
|
|
M. Zaeh (2), D. Siedl
|
|
STC M, 56/1/2007, P.383
|
|
Keywords: Finite element method (FEM), Structural analysis, Multi-body simulation |
Abstract : Machine tools need to work accurately and highly
dynamically to keep up with the requirements of modern machining
processes. Besides the technical issues, time to market is too short
to build a real prototype in future. This leads to the necessity for a
method which enables the forecast of the future machine
performance. To predict the machining results exactly, large movements
on flexible structures have to be calculated. With the specific
integration of FEA and MBS for the domain of machine tools it is
possible to predict the dynamic machine behaviour. The simulation
system is based on the relative nodal method for large deformation
problems. A model of a machine tool with all relevant components was
simulated and matched with experiments to demonstrate the approach.
|
|
Modeling and Identification of an Industrial Robot for Machining Applications
|
|
E. Abele (2), M. Weigold, S. Rothenbücher
|
|
STC M, 56/1/2007, P.387
|
|
Keywords: Robot, Machining, Structure model |
Abstract : Industrial robots represent a promising, cost-saving and
flexible alternative for machining applications. Due to the kinematics
of a vertical articulated robot the system behavior is quite different
compared to a conventional machine tool. This article describes the
modeling of the robot structure and the identification of its
parameters with focus on the analysis of the system's stiffness
and its behavior during the milling process. Therefore a method for
the calculation of the Cartesian stiffness based on the polar
stiffness and the use of the Jacobian matrix is introduced. Based on
the results of the identification and the experimental validation the
machining performance of the robot is evaluated and conclusions are
drawn.
|
|
Precision Compensators Using Giant Superelasticity Effect
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E.I. Rivin (1)
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STC M, 56/1/2007, P.391
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Keywords: Compensation; Tooling; Shape Memory Alloy |
Abstract : Elastic compensators for overconstrained precision devices
can be separate components or integrated, e.g. as in HSK
toolholders. The latter require precision complex surfaces and are
expensive, the former require small springs allowing large
deformations. The paper describes a recently discovered Giant
Superelasticity Effect (GSE), wherein wires or tubes made from a NiTi
superelastic material demonstrate 15-20% recoverable deformation when
compressed radially. They are mildly nonlinear and exhibit significant
damping. An effective method of attaching elastic tubes is
developed. Application of GSE to toolholder-spindle interfaces, with
significant reduction of runout, increased stiffness and damping is
described.
|
|
Developments for High Performance Machine Tool Spindles
|
|
C. Brecher (2), G. Spachtholz, F. Paepenmüller
|
|
STC M, 56/1/2007, P.395
|
|
Keywords: Machine, Spindle, Bearing |
Abstract : One important demand on spindle systems in modern machine
tools is to realise higher rotational speeds in order to increase the
machining efficiency. Additionally, for a given speed range a better
robustness is demanded so that the spindle system is desensitised
against improper operating conditions. The paper presents research
results in various fields which contribute to the improvement of
spindle-bearing systems. At first, new results for alternative spindle
bearing kinematics with four contact points are presented. Secondly, a
new solution for floating bearing arrangements is discussed. A
modified cylindrical roller bearing is presented which can be operated
at higher speeds. Finally, the potential of coated bearing components
is discussed in the context of improved fail-safe properties. In this
paper both analytic studies and experimental tests are presented.
|
|
Analytical Modeling of Chatter Stability in Turning and Boring Operations: A Multi-Dimensional Approach
|
|
E. Budak (2), E. Ozlu
|
|
STC M, 56/1/2007, P.401
|
|
Keywords: Chatter, Turning, Boring |
Abstract : In this study, an analytical model for the stability of
turning and boring processes is proposed. The proposed model is a step
ahead from the previous studies as it includes the dynamics of the
system in a multi-dimensional form, uses the true process geometry and
models the insert nose radius in a precise manner. Simulations are
conducted in order to compare the results with the traditional
oriented transfer function stability model, and to show the effects of
the insert nose radius on the stability limit. It is shown that very
high errors in stability, which limit predictions can be caused when
the true process geometry is not considered in the calculations. The
proposed stability model predictions are compared with experimental
results and an acceptable agreement is observed.
|
|
Development of a Medical CAD/CAM System for Orthopedic Surgery
|
|
M. Mitsuishi (2), N. Sugita, K. Fujiwara, N. Abe, T. Ozaki, M. Suzuki, H. Moriya, T. Inoue, K. Kuram
|
|
STC M, 56/1/2007, P.405
|
|
Keywords: CAD, CAM, Biomedical |
Abstract : In successful knee arthroplasty, the femur and the tibia
must be shaped to fit an artificial joint. The recent trend towards
MIS (Minimally Invasive Surgery) to decrease the length of the
required incision in the skin has increased surgical difficulty, since
the open access area is small. The developed system consists of (1) a
preplanning system providing a CAD function, (2) a multi-axis CAM
system which avoids cutting the skin and the ligament, and keeps the
cutting time within acceptable limits, and (3) a 7-axis machine tool
that assures the safety of the patient and the surgeon, and enables
MIS.
|
|
Quick 3D Modeling of Machining Environment by Means of On-machine Stereo Vision with Digital Decomposition
|
|
X. Tian, H. Deng, M. Fujishima, K. Yamazaki (1)
|
|
STC M, 56/1/2007, P.411
|
|
Keywords: Geometric modeling, Object recognition, Virtual CCD camera |
Abstract : The paper describes a three dimensional vision-based
modeling system, which can efficiently and accurately construct solid
models of a machining environment including the workpiece setup with
jigs and fixtures on the machine table. The unique methods of the
object recognition with various key technologies have been developed
based on the simultaneous real and virtual stereo image
processing. Since the constructed model accurately matches with the
real setup, real time NC program verifications can be performed for
100% collision-free machining simulation. The prototyped system has
been successfully verified by implementation on several real machining
systems.
|
|
A More Realistic Cutting Force Model at Uncut Chip Thickness Close to Zero
|
|
H. Paris, D. Brissaud (1), A. Gouskov
|
|
STC M, 56/1/2007, P.415
|
|
Keywords: Cutting, Force, Mode |
Abstract : The relevance of the results of many machining simulations
depends on the quality of the cutting force model used. Most of the
cutting force models raise problems for uncut chip thickness close to
zero. It is mainly due to the management of strong discontinuity and
the infinitive limit of the cutting stiffness when the uncut chip
thickness goes to zero. Furthermore, the correlation of these models
with the experimental results is not very good at low and high uncut
chip thickness. To resolve these difficulties, a new model of cutting
force is proposed. It gets the advantage to be a continuous law with a
finished limit of cutting stiffness when the uncut chip thickness goes
to zero. The validation of this model with experimental results in
milling and drilling shows a good correlation for a large variation of
uncut chip thickness.
|
STC O |
|
Strategic Development of Factories under the Influence of Emergent Technologies
|
|
E. Westkämper (1)
|
|
STC O, 56/1/2007, P.419
|
|
Keywords: Manufacturing, Management, Development |
Abstract : Structure and management of factories are heavily
influenced by the implementation of emergent technologies and
objectives for economic efficiency in the turbulent environment. A
generic model of Technology Management for the development of
factories constitutes the kernel of this paper. It includes trends of
technologies and industrial priorities for research which have been
defined in the European Road-Mapping Process for the Manufuture
Platform. The investigations and road-mapping processes lead to
structural changes towards new generations of adaptable factories -
engineered with knowledge-based engineering systems and operating in
an ubiquitous information and communication (Grid Manufacturing)
environment. The paper shows the paradigms of holistic production
systems (factories as products).
|
|
A Toolbox Approach for Flexibility Measurements in Diverse Environments
|
|
K. Georgoulias, N. Papakostas, S. Makris, G. Chryssolouris (1)
|
|
STC O, 56/1/2007, P.423
|
|
Keywords: Flexibility, Measurement, Manufacturing |
Abstract : Flexibility evaluation remains a key issue for modern
manufacturing systems. The complexity of the industrial practice leads
often to empirical evaluation tailored to a specific application. This
paper suggests a holistic approach with the employment of a
flexibility evaluation toolbox, together with a framework, to manage
business process changes. The synthesis of the flexibility evaluation
toolbox has been formed by quantitative evaluation algorithms in order
for a wide range of applications to be covered. The proposed concept
has been demonstrated in an industrial case.
|
|
Evolving Production Network Structures
|
|
M. Grunow, H.O. Günther, H. Burdenik, L. Alting (1)
|
|
STC O, 56/1/2007, P.427
|
|
Keywords: Production, Optimization, Global Manufacturing Network |
Abstract : When deciding about future production network
configurations, the current structures have to be taken into
account. Further, core issues such as the maturity of the products and
the capacity requirements for test runs and ramp-ups must be
incorporated. Our approach is based on optimization modelling and
assigns products and capacity expansions to production sites under the
above constraints. It also considers the production complexity at the
individual sites and the flexibility of the network. Our
implementation results for a large manufacturing network reveal
substantial possible cost reductions compared to the traditional
manual planning results of our industrial partner.
|
|
Solution Approaches to Real-time Control of Customized Mass Production
|
|
L. Monostori (1), B. Kádár, A. Pfeiffer, D. Karnok
|
|
STC O, 56/1/2007, P.431
|
|
Keywords: Scheduling, Control, Optimisation |
Abstract : The paper summarises the main challenges and problems
related to customised mass production. In the elaborated solution the
reference for real-time production control is generated by a novel
scheduling sys-tem. Detection of changes and disturbances emerging
during the daily production is based on the integra-tion of
information coming from the process, quality and production monitoring
subsystems. All the infor-mation forms the basis of rescheduling
policies. In the proposed framework both the more traditional
dis-crete event simulation (in different settings) and the agent-based
approach plays key role. The effective-ness of the proposed solutions
is shown by experimental results on industrial data.
|
|
Advanced Automation Solutions for Future Adaptive Factories
|
|
E. Carpanzano, F. Jovane (1)
|
|
STC O, 56/1/2007, P.435
|
|
Keywords: Factory, Reconfigurable, Automation |
Abstract : Factories of the future must be capable to adapt themselves
to continuously changing market demand. Therefore new manufacturing
technologies are needed: from agile operating machines up to internet
based services. In particular, new advanced automation solutions, that
integrate all factory levels in a unique real time framework, are
mandatory. Nowadays, neither accepted standards nor assessed
development methodologies and software environments are available to
support industries when facing such a crucial issue. In the present
contribution an open and modular automation system architecture is
proposed, based on emerging modelling paradigms and recent
international standards. Furthermore, a methodology to develop
self-adaptive factory automation solutions is illustrated, using a
novel modular simulation based method to verify digitally - through a
modular bottom up approach - the correctness of real size automation
systems. The proposed framework has been applied to a highly
innovative reconfigurable factory for personalised shoes
production. Such a real-size industrial application proves the
effectiveness and the benefits of the presented methods for the
development of complex automation solutions for high value added
production systems.
|
|
High Resolution Production Management
|
|
G. Schuh (2), S. Gottschalk, T. Höhne
|
|
STC O, 56/1/2007, P.439
|
|
Keywords: Planning, Scheduling, Open Architecture |
Abstract : High Resolution Production Management describes the
approach to set up a network of sensors for online order
identification and localisation in production consisting of new and
existing information technologies such as Radio Frequency
Identification (RFID), Programmable Logic Controllers (PLC) and
Personal Digital Assistants (PDA). It is intended to establish a new
order optimisation principle between the interlaced planning levels,
which allows an improved real-time decision making. Finally, a
software architecture is proposed which allows for a consistent
interaction of the heterogeneous planning and control systems. The
paper introduces the approach and first concepts of High Resolution
Production Management and presents first experiences of application to
industrial cases.
|
|
Turbulence Germs and their Impact on Planning and Control - Root Causes and Solutions for PPC Design
|
|
H.H. Wiendahl / G. Spur (1)
|
|
STC O, 56/1/2007, P.443
|
|
Keywords: Management, Planning, Turbulence |
Abstract : Abrupt and often surprising changes characterize the market
situation of production companies. Important aspects for the design of
production planning and control (PCC) are those which potentially
cause turbulence and lead to schedule deviations. The paper describes
a method to capture these changes qualitatively and assess them
quantitatively, while identifying solutions for PPC design. Its
theoretical fundament draws on an analogy to physics and develops the
morphology of turbulence germs. A case study illustrates its
application in detail, starting with a company-specific turbulence
profile, analyzing the root causes quantitatively and identifying
solutions for improving PPC.
|
|
Chaordic Systems Thinking for Novelty in Contemporary Manufacturing
|
|
F.M. van Eijnatten, G.D. Putnik, A. Sluga (2)
|
|
STC O, 56/1/2007, P.447
|
|
Keywords: System, Management, Complexity |
Abstract : The paper describes a framework for novelty creation, based
in complexity, and how it enables the management for novelty in
manufacturing systems. The paper's central thesis is that
complexity should not be eliminated but nurtured. The human role is
focused on. The paper evaluates how the creation of novelty is
recognized in existing MS approaches such as Collaborative Design,
Complexity, Emergent Synthesis, and Networked Organizations. A
complexity framework is proposed to develop a chaordic manufacturing
system.
|
|
Techniques for Planning and Control Dependent on Different Types of Flexibility
|
|
P. Schönsleben / J. Milberg (1)
|
|
STC O, 56/1/2007, P.451
|
|
Keywords: Flexibility, Decision Making, Operations Management |
Abstract : The implementation of a particular technique for planning
and control of capacities, materials, and other resources for
production is strongly dependent on what type of flexibility, in a
strategic, tactical, or operations view, is the center of
attention. For decision making, two-dimensional visualizations, with
the horizontal axis and the vertical axis each representing a certain
type of flexibility, have proved practical. This decision aid proves
advantageous especially when the decision is made jointly and the
reasons for the decision need to be communicated to other persons
in the job shop, for example. The paper presents examples of
concepts and techniques for capacity and materials planning, and
further areas where the decision aids can be used.
|
|
Impact of Product Life Cycle on Manufacturing Systems Reconfiguration
|
|
K.K.B. Hon (1), S. Xu
|
|
STC O, 56/1/2007, P.455
|
|
Keywords: Product, Lifecycle, Reconfiguration |
Abstract : The dynamics of product life cycle for a family of products
presents a complex manufacturing scenario. As the demand pattern is
ever changing, the manufacturing system also has to be reconfigured in
order to align its production capability with demand. This paper
addresses the complex relationship between the product life cycle for
a family of products and the manufacturing systems performance
optimization via reconfiguration. The optimization strategy consists
of three main steps: simulation of the original configuration,
optimisation of the reconfigured system and finally product portfolio
optimisation. Full discussions on results are given in terms of system
sensitivity and optimization efficiency and the deployment of
reconfiguration.
|
|
Universal Manufacturing Platform for CNC Machining
|
|
S.T. Newman, A. Nassehi / A.N. Bramley (1)
|
|
STC O, 56/1/2007, P.459
|
|
Keywords: Computer Aided Manufacturing, Integration, Interoperability |
Abstract : Today, CNC technology is a major contributor to the
production capacity of industrial companies. The current NC standards
only allow rudimentary low-bandwidth information transfer between
various resources. A complex network of post-processors is therefore
needed for the basic functionality of CAD/CAM/CNC systems. In this
paper, the authors investigate and design a universal platform for
supporting CNC manufacturing. The platform shifts the necessary
knowledge transformations from the vendor specific software domain to
the conceptual model space. This will eliminate the requirement for
postprocessors. Consequently, resources will be interchangeable and
interoperable, adding to the strategic agility of the manufacturing
network.
|
|
An Emergent Synthesis Approach to Simultaneous Process Planning and Scheduling
|
|
K. Ueda (1), N. Fujii, R. Inoue
|
|
STC O, 56/1/2007, P.463
|
|
Keywords: Manufacturing system, Emergent synthesis, Evolutionary artificial neural network |
Abstract : Optimality of a process plan and a production schedule
frequently conflict. It is difficult to determine a proper plan that
meets both objectives simultaneously. This paper proposes a new
simultaneous process planning and scheduling method to solve dilemmas
posed by such situations using evolutionary artificial neural networks
based on emergent synthesis. The effectiveness of the proposed method
is confirmed by solving a benchmark problem, thereby demonstrating
high productivity resulting from role-sharing among machines. Results
also show that the proposed method is applicable to more realistic
problems including larger volumes of products and production demand
fluctuations.
|
|
Mathematical Modeling for Reconfigurable Process Planning
|
|
A. Azab, H.A. ElMaraghy (1)
|
|
STC O, 56/1/2007, P.467
|
|
Keywords: Computer automated process planning, Mathematical programming, Reconfigurable process planning |
Abstract : The paradigm shift in manufacturing systems and their
increased flexibility, and changeability require corresponding
responsiveness in support functions to achieve cost-effective
adaptability. Reconfigurable Process Planning (RPP) is an important
enabler of changeability for evolving products and
systems. Mathematical programming and formulation is presented, for
the first time, to reconfigure process plans to account for changes in
parts' features beyond the scope of the original product
family. Reconfiguration of precedence graphs to optimize the scope and
cost of process plans reconfiguration is achieved by
inserting/removing features iteratively using a novel 0-1 integer
programming model. The proposed RPP mathematical scheme scales better
with problem size compared with classical process planning models. The
formulation of the mathematical model at each iterative step of
reconfiguration has been automated. A process plan reconfiguration
index (RI) that captures the extent of changes in the plan and their
implications has been introduced. A prismatic benchmark and an
industrial case study are used for illustration and verification. The
computational behavior and advantages of the proposed model are
discussed, analyzed and compared with classical models.
|
|
Extendible Operation Sequencing for Turn-Milled Components
|
|
T. Mwinuka, S. Hinduja (1), O.O. Owodunni
|
|
STC O, 56/1/2007, P.473
|
|
Keywords: CAPP, Operation Sequencing, Customisation |
Abstract : Research in operation sequencing has hitherto been based on
fixed heuristics with no obvious scientific basis. Often, the
heuristics contain no technological considerations. This paper
provides a scientific approach for the sequencing of features based on
maximising the stiffness of the intermediate component. In the case of
intersecting feature volumes, preference is given to a feature with a
lower machining cost. This scientific approach is embedded within a
flexible environment in which heuristic rules can be constructed from
a rich vocabulary covering geometric and technological attributes,
without the need for additional programming. Examples illustrating the
capabilities of the system are described.
|
|
Extended Multi-Customer Supplier Parks in the Automotive Industry
|
|
W. Sihn (2), K. Schmitz
|
|
STC O, 56/1/2007, P.479
|
|
Keywords: Logistics, Integration, Supplier Parks |
Abstract : One great challenge for OEMs is to manage the complex
supply processes. In order to reduce this complexity, they could
integrate large suppliers into so-called Automotive Supplier Parks. In
the end, large suppliers would have many small one-to-one plants in
Supplier Parks with low economies of scale and high costs. This paper
illustrates the key problems of traditional Supplier Parks and
presents a new solution: the concept of Extended Multi-Customer
Supplier Parks (MCSP+). Requirements, logistic processes and
structures will be explained. Furthermore, the paper will present an
approach to integrate suppliers in an MCSP+ that are not located in a
Supplier Park.
|
|
Practical Applications of Logistic Operating Curves
|
|
P. Nyhuis / H.P. Wiendahl (1)
|
|
STC O, 56/1/2007, P.483
|
|
Keywords: Optimisation; Production; LOC Theory |
Abstract : CIRP Papers presented in 2005 and 2006 introduced the
Logistic Operating Curves (LOC) and explained their theoretical
basics. Following up these articles, this paper outlines possible
practical industrial applications. Generally, LOC can be applied for
controlling and upgrading both the logistic processing reliability and
processing capability. Based on the concept of Logistic Positioning
the article focuses on how to identify logistic potentials and how to
derive suitable measures by means of LOC. In addition, approaches to
flow rate oriented scheduling and calculating lot sizes are
introduced.
|
|
A Rolling Horizon Approach to Plan Outsourcing in Manufacturing-to-Order Environments Affected by Uncertainty
|
|
T. Tolio (2), M. Urgo
|
|
STC O, 56/1/2007, P.487
|
|
Keywords: Production Planning, Uncertainty, Machining centres |
Abstract : Production planning approaches considering availability of
complete information, usually fail to deal with real manufacturing
environments characterized by uncertainty affecting the time to
execute the manufacturing operations, the routing of the parts, the
requirement of materials and resources. This paper analyses the
problem of negotiation and planning of external resource usage in a
manufacturing system affected by uncertainty. In particular the need
of resources is considered uncertain and it is modelled through a
scenario based formulation. A rolling horizon approach is proposed
which applies a two-stage stochastic programming method against the
occurrence of multiple uncertain events.To demonstrate the viability
of the proposed approach, an application example based on a real
manufacturing plant producing machining centres is provided.
|
|
An Approach for Adaptability Modeling in Manufacturing - Analysis Using Chaotic Dynamics
|
|
N. Papakostas, D. Mourtzis (2)
|
|
STC O, 56/1/2007, P.491
|
|
Keywords: Flexibility, Nonlinear, Decision-making |
Abstract : In this paper, a novel approach for modeling the
adaptability of a manufacturing system is introduced. A mathematical
model for quantifying the adaptability of a manufacturing system is
discussed and real manufacturing data are used for its evaluation. A
set of tools, including maximal Lyapunov exponents and bifurcation
diagrams are then presented and applied in order to analyze the
behavior of a manufacturing system under different operational
policies and parameters. The objective of this work is twofold: a) to
quantify the ability of a manufacturing system to adapt to demand by
using minimal manufacturing data and b) to demonstrate that different
operational policies for adaptability in a manufacturing system may be
analyzed, by using non-linear and chaotic dynamics tools.
|
STC P |
|
Enhancement and Proof of Accuracy of Industrial Computed Tomography (CT) Measurements
|
|
M. Bartscher, U. Hilpert, J. Goebbels, G. Weidemann / H. Kunzmann (1)
|
|
STC P, 56/1/2007, P.495
|
|
Keywords: Coordinate Measuring Machine (CMM), X-ray, Uncertainty |
Abstract : Computed tomography (CT) is a well-established technology
in medical diagnostics. For a few years now, dedicated CT systems have
also been in use for dimensional measurements in industry. However, as
far as the accuracy and reliability of the results is concerned, many
problems are still unsolved. This paper de-scribes concepts and first
results for solving these problems. CT specific reference standards
and proce-dures for their application - similar to the acceptance and
verification procedures of classical coordinate measuring technology -
have been developed. In this paper, concepts and recent results are
presented. They illustrate the technological and technical aspects and
indicate the attractiveness of this new measure-ment technology.
|
|
Self-Calibration of On-Axis Rotary Encoders
|
|
X.D. Lu, D.L. Trumper (2)
|
|
STC P, 56/1/2007, P.499
|
|
Keywords: Calibration, Spindle, Encoder |
Abstract : This paper presents a new self-calibration method for
rotary encoders mounted on precision axes of rotation. By measuring
encoder pulse widths in the time domain, the angular distance
corresponding to each pulse is automatically derived from the spindle
free-response dynamics. This method has three distinctive features: 1)
instant calibration of the encoder error map without need for an angle
measurement instrument; 2) wide applicability to general encoders
without requiring multiple read-heads; 3) in-place calibration on the
target rotary axis rather than the axis of another calibration
system. Experiments and simulations have been conducted to
characterize the calibration repeatability and accuracy.
|
|
A Two Dimensional Scanning Setup for Precise Addressing of Fibers in a Fiber Bundle
|
|
R. Schmitt, K. Eder / T. Pfeifer (1)
|
|
STC P, 56/1/2007, P.505
|
|
Keywords: Metrology, Optical, Fiber |
Abstract : A fiber optical scanning set-up is
presented, which acts as a fiber addresser between an optical
measurement system and a flexible waveguide bundle. A light beam is
positioned and coupled into the optical fibers using a two-dimensional
scanning mirror setup. The fiber positions are detected and sorted
using software algorithms. After calibration, the fibers are read out
individually at high rates in order to generate the measurement
data. Multiplexing of an Optical Coherence Tomography (OCT) system
through a singlemode linear fiber array consisting of 100 fibers with
a core diameter of 5 µm is demonstrated.
|
|
Non-Contact and In-Process Measurement of Film Coating Thickness by Combining Two Principles of Eddy-Current and Capacitance Sensing
|
|
T.O. Kim, H.Y. Kim, C.M. Kim, J.H. Ahn (2)
|
|
STC P, 56/1/2007, P.509
|
|
Keywords: Eddy-current, Capacitance, Coating thickness measurement |
Abstract : A non-contact and in-process measurement method of film
thickness coated with dielectric materials on a base metal is
suggested. A dual sensor based on the combination of the principle of
eddy-current sensing and the principle of capacitance sensing is
developed. The dual sensor is mathematically modelled in consideration
of the physical characteristics of both sensing elements against the
base metal as well as the coating film. The simulation results from
the suggested model provide some information regarding the optimum gap
distance for real applications. The developed dual sensor is proven to
be accurate to less than ±1 μm through experiments for three
base metals with polyvinyl coatings of three different thickness.
|
|
An Ultrasound In-Process-Measuring System to Ensure a Minimum Roundness Deviation for Rings During Turning
|
|
D. Stoebener, M. Dijkman / C.J. Evans (1)
|
|
STC P, 56/1/2007, P.513
|
|
Keywords: Measurement, Ultrasonic, In-process measurement |
Abstract : The turning process requires a clamping of the
workpiece. If the fixing of a thin-walled workpiece (i.e. a ring) is
realised with a three-jaw-chuck, distortion of the outer diameter of
the workpiece occurs, leading to a varying circumferential wall
thickness on unclamping. This paper presents an ultrasound system for
the in-process-measurement of these workpiece distortions. The
measurement principle is based on the determination of phase
differences between echoes of an ultrasound burst. The measured
in-process values can be used to control the turning process with a
fast tool servo.
|
|
Geometrical Specification Model for Gear - Expression, Metrology and Analysis
|
|
J.Y. Dantan, J. Bruyere, C. Baudouin, L. Mathieu (1)
|
|
STC P, 56/1/2007, P.517
|
|
Keywords: Tolerancing Model, Functional Metrology, Gear |
Abstract : To ensure the gear precision,
industries need a coherent model to express, to analyse and to check
geometrical specifications. Most gear tolerance representations are
directly driven by the convenience of dimensional metrology and not by
the convenience of the set of activities of the tolerancing
process. Therefore, to ensure the coherence of all tolerancing process
activities, there is a necessity to develop a complete gear tolerance
model which should: represent standard tolerance practices; be
integrated in the Computer-Aided systems of design, manufacturing and
metrology; be controlled by CMM; and support automated tolerance
analysis. The proposed model extends capabilities of a vectorial
dimensioning & tolerancing model in order to satisfy the four
requirements. This model is based on GeoSpelling [1]. Its coherence is
illustrated by two applications: gear tolerance analysis and gear
tolerance verification by CMM.
|
|
A Novel Cooling System to Reduce Thermally-Induced Errors of Machine Tools
|
|
M.A. Donmez, M.H. Hahn, J.A. Soons / J. Bryan (1)
|
|
STC P, 56/1/2007, P.521
|
|
Keywords: Machine, Thermal, Error |
Abstract : This study explores a method to reduce thermally-induced
errors of machine tools through temperature stabilization with
compressed air. The method uses inexpensive, specially-shaped, silicon
tubing with small slits. Compressed air forced through such tubing
increases heat dissipation from the surface through Coanda-effect
cooling. This paper describes experiments performed on a simulated
heat source as well as a turning center to evaluate and improve the
effectiveness of the method. The results show that this system, which
can easily be applied to existing machines, can significantly reduce
thermal drift and may be a viable alternative to other methods to
reduce thermally-induced errors.
|
|
Long Range 3D Scanning Tunnelling Microscopy
|
|
A. Weckenmann (1), J. Hoffmann
|
|
STC P, 56/1/2007, P.525
|
|
Keywords: Measuring instrument, Scanning tunnelling microscope (STM), Nano technology |
Abstract : State of the art scanning tunnelling microscopes (STMs)
detect surfaces contactlessly with a needle-like probe and use
piezo-elements for realizing relative movements between probe and
specimen. This leads to a 2.5 D characteristic with a very small
measuring range of typically 100 µm x 100 µm x 10
µm. To overcome these deficiencies a new STM probing system
without moving parts has been designed, set-up with a special probing
element and integrated into a laser-interferometrically controlled
long-range nanopositioning unit. The resulting system features a
measuring range of up to 25 mm x 25 mm x 5 mm at a principal
resolution of 0.1 nm and is capable of true 3D measurements.
|
|
A Three-axis Displacement Sensor with Nanometric Resolution
|
|
W. Gao (2), A. Kimura
|
|
STC P, 56/1/2007, P.529
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Keywords: metrology, sensor, displacement |
Abstract : Instead of plane mirrors in a conventional Michelson
interferometer for measurement of Z-directional displacement, the
three-axis displacement sensor described in this paper employs two
sinusoidal XY-grid mirrors with identical pitches (10 microns) and
amplitudes (60 nm) of X- and Y-directional sine waves as the
stationary reference mirror and the moving scale mirror,
respectively. The positive and negative first-order diffraction light
beams from the two XY-grids superimposing with each other to generate
interference signals, from which the displacements of the scale grid
along the X-, Y-, and Z-axes can be simultaneously
obtained. Experimental results have verified that the sensor has
nanometric resolutions in all the three axes.
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High Aspect Ratio Nanometrology using Carbon Nanotube Probes in Atomic Force Microscopy
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F.Z. Fang (2) , Z.W. Xu, S. Dong, G.X. Zhang (1)
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STC P, 56/1/2007, P.533
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Keywords: Carbon nanotube, Atomic force microscopy, Metrology |
Abstract : Carbon nanotube (CNT) has several unique characteristics
that are ideal for applying it as probe for atomic force microscopy
(AFM). However, some of these characteristics make it inherently
difficult to produce CNT probes. This paper developed a novel welding
process that can produce nanotube probe at different lengths. The new
process could control CNT probe orientation well and achieve bonding
strength of greater than 306 MN/m2. In an AFM scanning of
immunoglobulin G protein and aluminum oxide, nanotube probes show
better probe wear resistance, lower sample damage and a higher aspect
ratio of 2.3 times than conventional silicon probes.
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Extraction of the Mechanical Surface in Measurement of Nano Structures
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M. Dietzsch (1), S. Gröger (1), M. Gerlach (1), M. Krystek (2) / P. Vanherck (1)
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STC P, 56/1/2007, P.537
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Keywords: Tactile measurement, Roughness, Nano Technology |
Abstract : The basic problem of measuring real surfaces with a tactile
probe is the distortion of the measured profile due to the tip
geometry in comparison with the real profile. The bigger the ratio of
the characteristic dimension of the tip and the shortest describing
wavelength of the surface, the larger the relative distortion will
be. That must especially be taken into account in case of the
measurement of nano structures. To reverse this distortion a
morphological operation for the reconstruction of the mechanical
surface is investigated. The results demonstrate the efficiency and
the limits of the reconstruction to obtain the mechanical surface,
which also depends on the morphological extraction theorem.
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STC S |
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Fabrication of Ultra Precision Optics by Numerically Controlled Local Wet Etching
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K. Yamamura / T. Masuzawa (1)
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STC S, 56/1/2007, P.541
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Keywords: Etching, Numerical control, Optical |
Abstract : In this paper, the author presents a novel noncontact
subaperture deterministic figuring method, named numerically
controlled local wet etching (NC-LWE), for fabricating ultraprecision
optics or finishing functional materials. In this method, a localized
wet etching area is formed using a combined nozzle that is composed of
a coaxially arranged supply part and a suction part for the
etchant. In the system, the removal volume at any point on the
workpiece surface is determined by the dwelling time of the
nozzle. The author applied this method to finish a photomask substrate
made of synthetic quartz glass (6 inches), and achieved 56 nm peak to
valley flatness with 0.15 nm rms roughness.
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Geometrical Accuracy and Optical Performance of Injection Moulded and Injection-compression Moulded Plastic Parts
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W. Michaeli, S. Hessner, F. Klaiber, J. Forster / W. Eversheim (1)
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STC S, 56/1/2007, P.545
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Keywords: Design, Mould, Optical |
Abstract : The manufacturing of optical components by injection
moulding and injection-compression moulding is a serious challenge for
tool and machine technology as well as for process control. To
evaluate the quality of optical parts the accuracy of the moulded
geometry as well as the resulting optical performance has been
analysed. At present a geometrical moulding accuracy in the lower
micron range has been achieved for the production of thick-walled
lenses. Overall injection-compression moulded lenses showed a better
optical performance than injection moulded lenses. To further improve
the resulting geometrical quality, local material shrinkage can be
compensated by precisely modifying the cavity contour.
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Surface Segmentation by Variable Illumination
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F. Puente León (2), C. Lindner, D. van Gorkom
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STC S, 56/1/2007, P.549
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Keywords: Surface topography, Image analysis, Automated visual inspection |
Abstract : Surface segmentation is a method to divide a surface into
areas of homogeneous properties. Meaningful surface properties, such
as the reflection characteristics or the local surface orientation,
are derived from series of images by estimating the parameters of a
reflection model. The images of the series show the surface
illuminated from variable directions. A priori knowledge about the
surface geometry can be used to improve the illumination
strategy. Segmentation results often correlate with surface defects
and thus can be applied as preprocessing step for a subsequent
detection of defects. The performance of the approach is demonstrated
with test specimens and cutting tools.
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Freeform Surface Characterisation - A Fresh Strategy
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X. Jiang, p. Scott, D. Whitehouse (1)
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STC S, 56/1/2007, P.553
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Keywords: Surface, Geometry, Evaluation |
Abstract : Many of the surfaces required today, and in the future, in
high added value products can have any designed shape and often no
axis of rotation. These complex geometrical surface shapes are termed
freeform surfaces. In most cases, these surfaces are required to have
sub-micrometer form accuracy and nanometric surface topography. This
paper introduces some new and novel concepts to classify and evaluate
freeform surfaces, including a structured neighbourhood signature
fitting method for smooth freeform surfaces and a tessellation
technique to identify and characterise micro-structured
surfaces. Examples will be used throughout the paper to illustrate
these new concepts.
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Feature-Oriented Measurement Strategy in Atomic Force Microscopy
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E. Savio (2), F. Marinello, p. Bariani, S. Carmignato
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STC S, 56/1/2007, P.557
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Keywords: Atomic force microscopy, Pattern, Control |
Abstract : In this paper a new measurement approach is presented; the
probe is driven over the sample surface according to a
feature-oriented measurement strategy, in order to scan with high
resolution just the discrete features of interest. Such intelligent
tip motion is made possible by re-programming of the actuation system
through a software interface with the instrument control. This new
approach optimizes the measurement operations, enabling the selection
of higher resolutions where needed and allowing for considerable
measurement time reduction. Furthermore, minimisation of the total
scanned length allows a reduction of tip wear. The proposed method was
tested on the characterization of complex microstructures. Results are
discussed in terms of advantages and limitations in comparison to
traditional raster scanning measurements.
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Dynamic Phenomena at Mode-I Crack Front in Silicon Simulated by Extended Molecular Dynamics
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T. Inamura (2), N. Takezawa, K. Shibuya, K. Yamada
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STC S, 56/1/2007, P.561
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Keywords: Simulation,Brittle fracture,Microdynamics |
Abstract : Analytical-solution-controlled molecular dynamics that can
simulate atomic-scale phenomena around a crack front has been extended
so that it can also simulate phenomena caused dynamically by
elastic/plastic waves. The result of the simulation for
monocrystalline silicon shows that a quasi-statically opening crack
creates voids arond the crack front and leaves dimples on the
fractured surfaces as in cases of ductile fracture. On the other hand,
elastic/plastic waves emitted from around the crack front change the
above phenomena such that various surfaces, from smooth to very rough
ones, result. A smooth surface is created by a Rayleigh wave that
travels along fractured surfaces, creating new surfaces at its
wavefront, while a rough surface is made by a chain mechanism wherein
a void is created by wave-driven cross slip and this void, in turn,
emits new waves which cause voids.
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Stress Assisted Dissolution of Biomedical Grade CoCrMo: Influence of Contact Loads and Residual Stresses
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A. Chandra, A. Mitchell, p. Shrotriya, D.A. Lucca (1)
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STC S, 57/1/2007, P.565
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Keywords: Surface, Residual stress, Dissolution |
Abstract : Mechanical load assisted dissolution is identified as one
of the key mechanisms governing material removal in fretting and
crevice corrosion of biomedical implants. In the current study,
material removal on a stressed surface of cobalt-chromium-molybdenum
(CoCrMo) subjected to single asperity contact was investigated in
order to identify the influence of contact load and residual stress on
dissolution rates. A range of known stress levels were applied to the
specimen while the surface was mechanically stimulated in ambient
conditions as well as different aqueous environments ranging from
non-reactive to oxidizing. Dissolution rate was found to display a
complex dependence on residual stress and environment.
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Microscopic Grinding Effects on Fabrication of Ultra-fine Micro Tools
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H. Ohmori (2), K. Katahira, T. Naruse, Y. Uehara, A. Nakao, M. Mizutani
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STC S, 56/1/2007, P.569
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Keywords: Grinding, Micro tool, Surface quality |
Abstract : A developed grinding system employing super-fine abrasive
wheels was used to fabricate ultra-fine micro-tools having a variety
of shapes. The machine successfully produced a cylindrically shaped
micro-tool having a tip diameter of less than 1 µm. The surfaces
of the produced micro-tools were investigated by advanced analytical
methods. Fracture strength of the micro-tools was evaluated by
nano-indentation testing, and their surface chemical properties were
analyzed by XPS. The results suggest that the surface of processed
micro-tools might have been strengthened by allowing the penetration
and diffusion of oxygen atoms into the material, and allowing
oxidation.
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Surface Properties of Diamond Coatings for Cutting Tools
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L. Settineri (2), F. Bucciotti, F. Cesano, M.G. Faga
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STC S, 56/1/2007, P.573
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Keywords: Surface, Diamond, Tool |
Abstract : In this paper diamond films, resulting from two Chemical
Vapour Deposition (CVD) techniques used to deposit diamond on Hard
Metal (HM) tools, are compared. Experimental assessments of film
morphology, interface properties, diamond quality and homogeneity are
presented, and related to the outcome of cutting experiments used to
test the coatings performance in turning operations of Metal Matrix
Composite (MMC) materials, a typical application field for
diamond-coated tools. Tool life and wear mechanisms are analysed in
comparison to those of a commercial CVD diamond coated tool, and of an
uncoated tool.
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Repair of Damaged Mold Surface by Cold-Spray Method
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J.C. Lee, H.J. Kang, W.S. Chu, S.H. Ahn (1) / S.I. Oh (1)
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STC S, 56/1/2007, P.577
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Keywords: Surface, Mold, Deposition |
Abstract : Thermal-mechanical loads during molding can cause wearing
of the surfaces of the molds. In this research, a mold repair
technique at low temperature was developed by applying cold-spray
deposition. Aluminum particles were deposited on top of the damaged
aluminum mold. The original mold surface was recovered by milling the
deposited material. Material properties such as hardness, coefficient
of thermal expansion, chemical composition, wear resistance, and
machinability of the mold and repaired layer were characterized. To
verify the recovered molding capability, polymer (Polystyrol) products
were fabricated by injection molding using the repaired
mold. Experimental results showed that the mold repair process using
cold-spray deposition and machining can be applied in the mold repair
industry.
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