CIRP ANNALS 2005
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STC A |
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Determining the Reuse Potential of Components Based on Life Cycle Data
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S. Kara, M. Mazhar, H. Kaebernick (1), A. Ahmed
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STC A, 54/1/2005, P.1
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Keywords: Life Cycle, Reuse, Condition Monitoring |
Abstract : Reuse of components is one of the most efficient strategies
for product recovery, which requires reliable methods for assessing the
quality and the remaining life of used components. A new methodology,
presented in this paper, is based on the trend analysis of lifetime
monitoring data. Data with similar trends were grouped and a number of
analysis techniques such as Linear Multiple Regression, Dynamic Ordinary
Kriging, Universal Kriging and Neural Networks were applied in order to
find the most suitable methodology for each group. The methodology was
validated by using lifetime monitoring data from a consumer product.
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Integration of Maintenance Strategies into Prognosis Process to Decision-Making Aid on System Operation
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B. Iung, M. Véron (1), M.C. Suhner, A. Muller
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STC A, 54/1/2005, P.5
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Keywords: Maintenance, Decision-Making, Predictive |
Abstract : The importance of maintenance function has increased due to
its role in keeping and improving the system availability and safety but
also the product quality. To support this new role, the maintenance
concept has undergone through several major developments to lead to
proactive considerations mainly based on prognosis process allowing
normally to select the best maintenance action to carry out. In this
paper the extension of a prognosis process by means of the integration
of maintenance alternative impacts is proposed. The deployment of this
extended prognosis process follows a methodology based both on
probabilistic and event approaches. The feasibility and added value of
this new prognosis is experimented on the manufacturing TELMA platform
supporting the unwinding of metal bobbins
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Product Redesign Using Value-Oriented Life Cycle Costing
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D. Janz, W. Sihn /H.-J. Warnecke (1)
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STC A, 54/1/2005, P.9
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Keywords: Cost, Lifecycle, Methodology |
Abstract : A new redesign approach has been developed considering the
perspective of a designer who wants to im-prove product performance over
the whole life-cycle while simultaneously optimising costs. Product
compo-nents can be identified which incur high costs compared to their
functional value. In order to identify the op-timisation potential, the
methods of Value Analysis, Quality Function Deployment and Life Cycle
Costing have been matched to each other and integrated into a
comprehensive concept. Based on a case study of vehicles, this paper
explains the theoretical approach and analyses for designers to optimise
costs and conduct product redesign by using Value-Oriented Life Cycle
Costing.
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Autonomous Visual Measurement for Accurate Setting of Workpieces in Robotic Cells
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A. Watanabe (3), S. Sakakibara, K. Ban, M. Yamada, G. Shen /T. Arai (1)
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STC A, 54/1/2005, P.13
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Keywords: Visual Measurement, Robot, Workpiece |
Abstract : This paper introduces a new method of adapting the virtual
world of an offline programming model to an actual robotic cell by
attaching a CCD camera to the robot. This method requires no specific
camera attachment location or optical camera calibration. Furthermore,
there is no operational requirement for setting robotic camera location.
Robot motion is autonomously generated to identify the camera view line.
The view line is adjusted to pass through the designated target point,
utilizing visual feedback motion control. This method calibrates
reference points between the virtual world of an offline model to an
actual robotic cell.
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Image based 3D Surveillance for flexible Man-Robot-Cooperation
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J. Krüger, B. Nickolay, p. Heyer /G. Seliger (1)
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STC A, 54/1/2005, P.19
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Keywords: Co-operative Assembly, Robot Safety System, Image Processing |
Abstract : In today's industrial production men and robots usually work
separately from each other in order to avoid accidents. By this, the
advantages of an interoperable automated and manual assembly can not be
used for a flexible and efficient production. If it would be possible to
overcome the separation of man and robot, the accuracy and speed of
robots could be combined with the flexibility and reliability of human
workers. Expecially for complex assembly and handling tasks, this
combination is useful. A system based on digital 3D image analysis has
been developed, which supervises the common working area of robot and man.
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A modular contactless feeder for microparts
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G. Fantoni, M. Santochi (1)
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STC A, 54/1/2005, P.23
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Keywords: electrostatic handling, modular feeder, micro assembly |
Abstract : This paper describes the development of a feeder for mini and
micro parts. A complete study of a feeding method based on electrostatic
fields is presented. Through a theoretical analysis and experimental
results the optimized configuration of the feeder is proposed, shown and
discussed. The performances of possible alternative configurations are
quantitatively compared according to the variation of the process
parameters. In addition the paper presents a flexible and reconfigurable
system based on standard modules easy to be linked by rapid set up
operations.
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Knowledge Acquisition from Assembly Operational Data Using
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P.F.Cunha /H-P. Wiendahl (1)
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STC A, 54/1/2005, P.27
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Keywords: Production and Maintenance planning, Performance evaluation, Multivariate statistical analysis. |
Abstract : Difficulties identified in the use of performance measures to
monitor and control manufacturing or assembly system behaviour justify
the evaluation method presented in this paper. The ability to improve
the effectiveness of both evaluation and decision-making tasks, based on
the knowledge acquisition from operational data, is an important
requirement for an effective planning and systems operation. The
proposed evaluation method is based on the use of multivariate
techniques - Principal Components Analysis and Cluster Analysis ? and
will prevent the loss of information in each available set of measures
and will promote effective use of data in the analysis of system
performance.
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Quality-driven Sequence Planning and Line Configuration Selection for Compliant Structure Assemblies
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H. Wang, D. Ceglarek (2)
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STC A, 54/1/2005, P.31
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Keywords: Assembly Sequencing, Dimensional Quality, Line Configuration Selection |
Abstract : Assembly sequence planning is an integral part of a new
product and process development. However, currently there are very few
available approaches to evaluate the impact of assembly sequences on
product quality. This paper develops a methodology for Quality-driven
Sequence Planning (Q/SP) with consideration to product dimensional
quality based on the following three steps: (1) Sequence generation for
predetermined line configurations using k-piece mixed-graph
representation of assembly; (2) Dimensional quality model of variation
propagation for assembly processes with compliant parts; and (3)
Evaluation of sequences based on the multivariate process capability
index. The methodology is illustrated using an industrial case study.
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STC C |
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A Rotating Cutting Tool to Remove Hard Cemented Deposits in Heart Blood Vessels without Damaging Soft Vessel Walls
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M. Nakao (2), K. Tsuchiya, W. Maeda, D. Iijima
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STC C, 54/1/2005, P.37
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Keywords: cutting, ceramic, grinding |
Abstract : A rotating cutting tool was developed to remove hard cemented
deposits in the heart blood vessels without damaging the soft vessel
walls. The new tool has a ?grater-like? configuration which is made of
anodized aluminum with 20mm high micro-blades on a 2mm diameter tip, and
it rotates at 200,000 rpm underwater. An evaluation test demonstrated
the feasibility of the new tool by cutting the hard shell, and not the
soft white, of a hardboiled egg. The water pressure forms a hydrodynamic
film around the tool tip to press down the soft tissue, protecting it
from any unwanted cuts.
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A Study of Bone Micro-Cutting Characteristics Using a Newly Developed Advanced Bone Cutting Machine Tool for Total Knee Arthroplasty
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M. Mitsuishi (2), S. Warisawa, N. Sugita, M. Suzuki, H. Moriya, H. Hashizume, K. Fujiwara, N. Abe, H
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STC C, 54/1/2005, P. 41.
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Keywords: Biomedical material cutting, Machine tool, Cutting force analysis |
Abstract : Bone cutting experiments were conducted on a cadaver using a
newly developed machine tool. The effectiveness of the system was
evaluated by comparing the planned shape for the mating surface between
the femur and an artificial joint with the cutting result. It is
desirable to know the machining phenomena and characteristics at the
microscale because the material and the tissue structure are anisotropic
in both cortical and cancellous bones. In the paper, the influence of
the material characteristics on machining is discussed for cortical
bone. Pig cortical bone was used in the experiment for visualizing
2-dimensional micro-cutting.
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Advanced Tool Edge Geometry for High Precision Hard Turning
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F. Klocke (1), H. Kratz
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STC C, 54/1/2005, P.47
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Keywords: Turning, Finite element method (FEM), Tool Cutting Edge |
Abstract : The hard turning process has been attracting interest in
different industrial sectors for finishing operations of hard materials.
However, it still presents disadvantages with respect to process
capability and reliability. In this paper the impact of PcBN tool edge
geometry is investigated based on a modelling as well as an experimental
approach. The hard turning process is described by means of a 3D
simulation of the tool engagement based on the Finite Element Method.
The simulation results indicate force and temperature distribution in
the tool-chip contact zone for different designs of PcBN tool cutting
edge, thus allowing the derivation of criteria for an advanced tool edge
design. The recommendations for tool edge geometry modification are
experimentally verified. The results suggest that the use of the
proposed new tool edge geometry is an effective way to significantly
increase tool performance with respect to tool life, material removal
rate and part surface quality in high precision hard turning.
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Mechanism of Cutting Edge Chipping and Its Suppression in Diamond Turning of Copper
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H. Tanaka, S. Shimada (1), M. Higuchi, T. Yamaguchi, T. Kaneeda, K. Obata
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STC C, 54/1/2005, P.51
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Keywords: Turning, Diamond, Cutting edge chipping |
Abstract : This paper investigates the mechanism of cutting edge chipping
in diamond turning of copper in terms of the change in Hertzian strength
of diamond specimens subjected to thermal histories. The study suggests
that the strength of diamond decreases as the result of the propagation
of existing surface micro cracks caused by the thermo-chemical erosion
of oxygen at the crack tips. The catalytic reaction involving copper is
also shown to accelerate the crack propagation. Then, a cutting
technique of reduced oxygen atmosphere is proposed to suppress the
cutting edge chipping in diamond turning of copper over an extended
cutting time.
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Analytical Modeling of Tool Wear Progression During Turning Particulate Reinforced Metal Matrix Composites
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H.A. Kishawy , S. Kannan , M. Balazinski (1)
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STC C, 54/1/2005, P.55
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Keywords: Cutting, Composite, Tool wear |
Abstract : This paper presents an analytical model for the prediction of
tool flank wear progression during bar turning of particulate reinforced
metal matrix composites. In this paper, a methodology for analytically
predicting the wear progression as function of tool/workpiece properties
and cutting parameters is presented. According to this approach, the
wear volume due to two body and three body abrasion is formulated. Then,
the flank wear rate is formulated by considering the tool geometry in 3D
turning. Turning tests were carried out for a range of cutting speeds,
tool nose radius and volume fraction of particles. The results showed
good agreement between predicted and measured tool wear progression.
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Innovative Methods for the Investigation of Tool-Chip Adhesion and Layer Formation during Machining
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R. M’Saoubi, H. Chandrasekaran (1)
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STC C, 54/1/2005, P.59
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Keywords: machining, Steel, Tool-chip adhesion |
Abstract : Tool-chip and tool-work adhesion often limit machinability,
but quantification methods to characterise adhesion are absent. Hence a
methodology based on interrupted turning was used and layer formation
was quantified using a number of techniques. This included surface
topography studies using 3D white light interferometry, element mapping
and profiling using SEM-EDS and Laser ablation time of flight mass
spectrometry (LA-TOFMS) along with temperature mapping using IR-CCD.
Results from turning tests with stainless steel 316L indicate clearly
that the above techniques compliment each other and provide valuable new
insight on contact friction, adhesion and layer formation.
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High Bandwidth Thermal Microscopy of Machining AISI 1045 Steel
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M.A. Davies (2), A.L. Cooke, E.R. Larsen
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STC C, 54/1/2005, P.63
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Keywords: High-speed Cutting, Finite Element Method, Thermal Microscope |
Abstract : A custom thermal microscope was constructed using a
high-bandwidth thermal imaging system (40 megapixels/sec). The
microscope was attached to a high-speed machining centre (20 thousand
RPM/18.5 kW spindle) that was operated as a high-speed lathe to measure
temperature distributions during orthogonal cutting of AISI 1045 steel
at surface speeds of up to 605 m/min. Measurements were made for a wide
range of cutting parameters and compared with finite element analysis.
While the ultimate goal is to produce improved tool design, the results
emphasize the need for predictive rather than interpretive simulation of
the temperature fields in machining.
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Cutting Force Estimation by Measuring Spindle Displacement in Milling Process
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J.H. Kim, H.K. Chang, D.C. Han (3), D.Y. Jang /S.I. Oh (1)
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STC C, 54/1/2005, P.67
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Keywords: End milling, Cutting, Sensor |
Abstract : A cylindrical capacitive displacement sensor (CCDS) was
developed and applied for monitoring end milling processes. Dynamic
characteristics of a spindle-assembly were measured using the CCDS and a
designed magnetic exciter. The technique to extract the spindle
displacement component caused only by cutting from the measured signals
using the CCDS was proposed in the paper. For the quantitative
estimation of dynamic cutting forces from the measured signals, a
mechanistic model considering tool deflection, which is derived from the
dynamics of the spindle tool system, was proposed.
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A Hybrid Cutting Force Model for High-speed Milling of Titanium Alloys
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Z.G. Wang, M. Rahman (1), Y.S. Wong, X.P. Li
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STC C, 54/1/2005, P.71
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Keywords: Cutting force model, finite element method, flow stress |
Abstract : In this paper, the Johnson-Cook (JC) strength model is used to
describe the flow stress of Ti6Al4V and to estimate two important
parameters in Oxley?s model: the strain-rate constant and the angle made
by the resultant force and the shear plane. The JC model is also
incorporated into a finite element method (FEM) simulation for the
deformation process of Ti6Al4V. Finally, a hybrid cutting force model
based on the FEM simulation and Oxley?s theory is proposed to predict
cutting forces when machining Ti6Al4V. Experimental results are found to
substantiate the developed model.
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Dynamic Load and Strain Analysis for the Optimization of Micro End Mills
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E. Uhlmann (2), K. Schauer
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STC C, 54/1/2005, P.75
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Keywords: Milling, Micromachining, Tool Design |
Abstract : Micro cutting using tungsten carbide end mills is
characterized by slender tools with low tool stiffness, high frequency
tool loads, as well as cutting widths and depths of less than 100 µm. An
analysis of dynamic loads and strains of tools with diameters as small
as 0.1 mm is not possible with conventional measurement equipment
because of its limited resolution and dynamics. Limited spatial
conditions in the machining zone are another restraint. In this paper,
measurement of the dynamic tool deflection by laser vibrometry and
measurement of cutting forces by a highly dynamic dynamometer during the
machining process are presented. The results are used to carry out a
FEM-based load analysis of the test tools. This analysis will show that
presently available micro end mills are not designed appropriately for
this type of load. Subsequently, a new parametric design of micro end
mills is introduced and validated by FEM-simulation. This innovative and
machining oriented tool design can be economically machined by grinding
technologies. Based on results of micro machining of mould steel PM
X190CrVMo 20, the successful verification of the newly adopted tools is
presented.
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Prediction of Parameters for the Burr Dimensions in Short-Hole Drilling
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U. Heisel (1), M. Luik, R. Eisseler, M. Schaal
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STC C, 54/1/2005, P.79
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Keywords: Cutting, Burr formation, Short-hole drilling |
Abstract : The following paper presents a method for the determination of
the burr dimensions to be expected in short-hole drilling,
simultaneously taking the parameters into consideration which influence
the burr formation. These parameters are yield stress, forces and the
geometry of the inserts. The method is based on empirical cutting
examinations and takes account into the correlation between different
burr parameters and the machining conditions such as cutting speed, feed
and tool geometry. Using Schaefer?s burr value g, it is possible to make
a quantitative evaluation of the burr dimensions. The method was
verified for the materials 16 MnCr 5 and Ck 45 in case of dry machining.
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Influence of Drill Dynamics on Bore Quality
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E. Abele (2), J. Elzenheimer , J. Hohenstein, M. Tschanner
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STC C, 54/1/2005, P.83
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Keywords: Drilling, Dynamic, Bore quality |
Abstract : Reaming, in addition to drilling processes, is necessary for
many applications in order to achieve the quality standards demanded.
The main reason why progress in precision drilling is hampered lies in
the incomplete understanding of the drill dynamics. This article
describes the dynamic influences of a carbide tool on the bore quality.
In contrast to most of the existing investigations which are based on
theoretical models that include only some influencing factors, this
article presents an experimental methodology to determine the bore
quality out of the frequency response. The results show strong
correlation between the shape accuracy and the frequency response.
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Broaching of Ti-6-4 ? Detection of Workpiece Surface Anomalies on Dovetail Slots through Process Monitoring
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D. Axinte, F. Boud, J. Penny, N. Gindy /D.J. Williams (1)
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STC C, 54/1/2005, P.87
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Keywords: Cutting, Monitoring, Surface anomaly |
Abstract : Surface anomalies induced by abusive broaching represent a
concern for the safety of critical components of aero-engines. Using
acoustic emission and force signals, the paper reports on process
monitoring techniques to detect surface anomalies when abusively
broaching dovetail slots in Ti-6-4. Parallel surface inspection helped
in defining the correlation between the occurrence of uneven events in
the output signals and the appearance/location of anomalies on the
broached surfaces. The findings support the definition of process
monitoring strategies to detect workpiece surface anomalies including
surface deformation/overheating, directed scoring and smearing of parent
material.
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Analytical Models Based on Composite Layer for Computation of Tool-Chip Interface Temperatures in Machining Steels with Multilayer Coated Cutting Tools
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W. Grzesik /C.A. van Luttervelt (1)
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STC C, 54/1/2005, P.91
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Keywords: Cutting, Tool coating, Temperature model |
Abstract : In this study the method of elementary balances (MBE) is
applied to predict the temperature fields in uncoated and coated carbide
cutting tools. Numerical computations are supported by the
experimentally/analytically obtained values of the contact length, the
total heat flux and the heat partitioning. The changes in the tool
temperature maps, resulting from variable thermal properties of tested
materials are considered. In particular, the distribution of temperature
across the thin film of 0.01 mm and corresponding temperature rise
distribution curves along the rake and flank faces are completely
displayed. The simulations have been validated against the measured
average rake face temperatures.
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Micro-blasting of PVD Films, an Effective Way to Increase the Cutting Performance of Coated Cemented Carbide Tools
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K.-D. Bouzakis (1), G. Skordaris, I. Mirisidis, G. Mesomeris, N. Michailidis, E. Pavlidou, G. Erkens
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STC C, 54/1/2005, P.95
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Keywords: PVD, Cutting, Micro-blasting |
Abstract : This paper investigates the feasibility of increasing the wear
resistance of cemented carbide tools through micro-blasting of their
PVD-coatings. The enhanced and graded film strength properties before
and after micro-blasting are determined by means of a FEM-based
evaluation of nanoindentation results. The coating topomorphy, induced
by micro-blasting, was monitored and correlated to the substrate
roughness and film adhesion. The cutting performance of inserts, coated
with micro-blasted films, was investigated in milling and explained with
the aid of a cutting process FEM simulation. The obtained results reveal
a tool life growth through micro-blasting of coatings, deposited on
substrates with appropriate roughness characteristics.
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The Machining of Gamma TiAl Internetallic Alloys
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D.K. Aspinwall (2), R.C. Dewes, A.L. Mantle
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STC C, 54/1/2005, P.99
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Keywords: Titanium, machinability, integrity |
Abstract : Titanium intermetallic materials are likely to play a
significant role in the production of future aeroengines. The paper
details the machinabilty of a range of gamma titanium aluminide (gamma
TiAl) intermetallic alloys when turning, grinding, HSM, drilling, EDM
and ECM. Comprehensive literature review data is augmented with
experimental results for turning, turn-milling and temperature
measurement when high speed milling. Despite the ability to produce
crack free surfaces when grinding and HSM, turning and drilling remain
problematic. Turned surfaces are in general characterised by workpiece
smearing, numerous arc shaped cracks, subsurface lamellae deformation
and significant strain hardening, although the use of PCD tooling and
ultrasonic assisted cutting has been shown to minimise these effects.
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A Study on Tribology in Minimal Quantity Lubrication Cutting
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S. Min, I. Inasaki (1), S. Fujimura, T. Wada, S. Suda, T. Wakabayashi
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STC C, 54/1/2005, P.105
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Keywords: Cutting, Tribology, Vibration |
Abstract : Despite the fact that minimal quantity lubrication (MQL)
machining produces almost similar cutting performance to conventional
flood supply machining while using much less metal working fluid (MWF),
it has not been fully utilized in industry due to lack of understanding
of the fundamental process physics. To take full advantage of MQL
machining and expand its applicability, an understanding of its
tribological behavior is critical. Hence, in this study, the adsorption
characteristics of MQL media during orthogonal cutting was investigated
using two experimental setups; one in a high vacuum chamber with a mass
spectrometer to observe mass changes of MQL media during cutting, and
another setup in an atmospheric chamber where the supply of MQL media
can be controlled. The former is mainly for analysis of the tribological
behavior of MQL media, and the latter for cutting performance
monitoring. It was found that the adsorption amount of MQL media was
closely related to lubrication behavior. Oxygen in MQL supply plays a
significant role in lubrication. Ultrasonic vibration cutting tests with
MQL were conducted for further understanding of lubrication mechanism.
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STC Dn |
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Design Requirements Management using an Ontological Framework
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R. Roy (2), C.I.V. Kerr, P.J. Sackett, J. Corbett (1)
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STC Dn, 54/1/2005, P.109
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Keywords: Design, Knowledge, Requirements management, Ontology |
Abstract : The specification activity is a critical enabler for
collaborative product development through an extended enterprise. Often
this activity involves numerous iterations before a shared understanding
of the product requirements is achieved since various omissions,
ambiguities and assumptions have to be resolved. This paper will present
a framework for the electronic-enabling of the requirements founded on
ontology-based constructs to provide a shared conceptualisation of the
knowledge needed for the specification of a product. The application of
ontology is a means to establish the consensual knowledge about the
needs of a product and to then apply this shared understanding for its
specification.
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Reusability Assessment for Manufacturing Systems
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J. Ko, S.J. Hu (2), T. Huang (2)
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STC Dn, 54/1/2005, P.113
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Keywords: Reuse, System, Manufacturing |
Abstract : Manufacturing firms have begun reconfiguring and reusing
production systems to save resources consumed on system changes that
were brought about by the high product variety and frequent model
change. As a result, assessing manufacturing system reusability has
become an important issue. This paper introduces intrinsic and effective
reusability of manufacturing systems and proposes quantitative metrics
to assess them. Using an automotive assembly system as example, this
paper also explores how system configurations and task allocation affect
reusability. Insights from such a study will help improve manufacturing
system reuse for families as well as generations of products.
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Mapping Knowledge about Product Lifecycle Engineering for Ontology Construction via Object-Process Methodology
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D. Dori, M. Shpitalni (1)
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STC Dn, 54/1/2005, P.117
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Keywords: Knowledge management, Lifecycle ontology, Object-process methodology |
Abstract : Knowledge mapping is a first and mandatory step in ontology
definition. This paper considers the lifecycle of products and systems,
and discusses the creation of a knowledge-based ontology. With respect
to the life cycle of products and systems, knowledge refers to the
processes involved in their creation (design manufacturing and
assembly), use and maintenance, and end of life (EOL). Hence, this
knowledge should consider what a product is comprised of (its
structure), how it operates (its dynamics), and how it interacts with
the environment. A clearly defined and consistent mapping of knowledge
regarding structure, operation and interaction is necessary to construct
an effective and useful ontology. Yet, in order to obtain the required
knowledge and to organize it in a consistent and useful form, an
appropriate ontology must be used. An interactive, iterative and
consistent method is needed to cope with this complex and circular
problem. In this paper, the Object-Process Methodology (OPM) approach is
considered, along with OPCAT ?[1], a tool for OPM-based knowledge
modeling. OPM is a systems-modeling approach that represents knowledge
about systems concurrently and bi-modally through graphics (a set of
Object-Process Diagrams, OPDs) and text (Object-Process Language, OPL, a
subset of English), yielding a single, unified and consistent view. In
this paper we propose a foundational modeling and ontology construction
approach for a generic product that incorporates hardware and software
components. The ontology can serve as a basis for a knowledge model to
cover the entire product lifecycle, from inception to EOL, and can be
applied in the VRL-KCiP Network of Excellence.
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Customised high-value document generation
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N. du Preez, N. Perry, A. Candlot, A. Bernard (1), W. Uys, L. Louw
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STC Dn, 54/1/2005, P.123
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Keywords: Methodology, Knowledge, Integration |
Abstract : Contributions of different experts to innovation projects
improve enterprise value, captured in documents. A subset of them is the
centre of expert constraint convergence. Their production needs to be
tailored case by case. Documents are often considered as knowledge
transcription. As the base of a structured knowledge-based information
environment, this paper presents a global approach that helps
knowledge-integration tool deployment. An example, based on process plan
in aircraft manufacturing, indicates how fundamental understanding of
domain infrastructure contributes to a more coherent architecture of
knowledge-based information environments. A comparison with an
experiment in insurance services generalised the application of
presented principles.
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A multi-level approach to edge detection in tessellated point clouds
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L.M. Galantucci (2), G. Percoco
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STC Dn, 54/1/2005, P.127
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Keywords: Reverse Engineering, Computer Aided Design, Edge Identification |
Abstract : Reverse Engineering software packages are not able to
automatically and robustly detect the sub-regions of a tessellated
model; it generally results in a first trial subdivision which
subsequently has to be refined, requiring a large amount of human
intervention and high computational effort. To avoid these limitations,
the authors propose a multilevel local approach for the automatic
identification of edge points in polygonized point clouds, exploiting
the ability of a heuristic technique to solve the edge detection problem
with low computational effort. The approach was applied to several
complex-shaped models with sharp and smooth edges, confirming its
robustness and efficiency.
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Surface Reconstruction for Interactive Modeling of Freeform Solids by Virtual Sculpting
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M.C. Leu (2), X. Peng, W. Zhang
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STC Dn, 54/1/2005, P.131
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Keywords: Surface Reconstruction, Contour, Virtual Sculpting |
Abstract : This paper presents a new method for surface reconstruction
from dexel data for virtual sculpting. This is part of our research
efforts to develop a dexel model based sculpting system with the
capability of interactive solid modeling with haptics interface. Dexel
data are converted to a series of planar contours in parallel slices
(i.e. cross sections). Then triangular meshes are created by connecting
the contour points in adjacent slices. Examples are given to demonstrate
the ability of the described method to convert from dexel data to
triangular meshes for the viewing of a sculpted model in different
directions.
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|
Feature-Based Alignment and Comparison between Portion and Whole of Free-Form Surfaces
|
|
Y. Li, p. Gu (1)
|
|
STC Dn, 54/1/2005, P.135
|
|
Keywords: Inspection, Alignment, Free-form Surfaces |
Abstract : In free-form inspection, it is often that only portion of a
surface has high precision requirements. This paper proposes a
feature-based automatic localization and comparison method for the
situation where the measurement surface is only a portion of the design
model. To make comparison, these two surfaces must be brought to a
common coordinate system which is called localization. The proposed
method localizes the portion surface to the whole surface through two
steps of localization process. The first step is general localization.
The corresponding features between the measurement surface and the
design model are searched. Based on the feature correspondence, the
measurement surface is localized very close to the design model. The
second step is fine localization that establishes the point-point
correspondence and localizes the surfaces more accurately.
|
|
A Design Method for Product Family under Manufacturing Resource Constraints
|
|
F. Kimura (1), J. Nielsen
|
|
STC Dn, 54/1/2005, P.139
|
|
Keywords: Design Method, Manufacturing System, Product Family |
Abstract : Product variety is required for satisfying customer needs, and
at the same time, efficient usage of manufacturing resources is
mandatory for competitive and environmentally conscious manufacturing.
For coping with these requirements, product family concept is effective,
which enables variety of products based on well designed similar product
property with associated manufacturing processes. In this study, a
modeling framework for relationship between product functionality and
manufacturing resources is discussed. Based on this framework, a design
method is investigated for product family structure which realizes
required product functional variety with efficient utilization of
manufacturing resources. Application examples are discussed for
automotive components.
|
|
Advanced Methods for a Realistic Styling
|
|
F.-L. Krause (1), A.R. Biahmou-Tchebetchou
|
|
STC Dn, 54/1/2005, P.143
|
|
Keywords: Conceptual Design, Method, Haptic rendering algorithm |
Abstract : One of the challenges of computer aided styling (CAS) consists
in rendering surface forces, which are generated by the interaction of
modelling tools and workpieces. Moreover, designers miss the form of
real modelling tools when using less intuitive devices for interacting
with digital systems. This paper describes methods, which allow a
realistic virtual prototyping by not only taking the form factor into
account, but also the appropriate haptic rendering algorithms as well.
|
|
Integrated Design Analysis for Product Simplification
|
|
G. Lucchetta, P.F. Bariani (1), W.A. Knight (1)
|
|
STC Dn, 54/1/2005, P.147
|
|
Keywords: Product Design, Integrated Functional Evaluation, Product Structure Simplification |
Abstract : A systematic methodology is presented for product structure
simplification through an integration of Design for Manufacture and
Assembly (DFMA) with the Theory of Invention Problem Solving (TRIZ). A
new functional model is combined with a selection of TRIZ problem
solving tools that are identified as effective in product structure
simplification. DFMA analysis is used to evaluate alternative concepts.
Application of the combined approach is illustrated through a case study
of a heavy duty stapler.
|
|
Fuzzy Multicriteria Decision Aid Method for Conceptual Design
|
|
R.A. Gheorghe, A. Bufardi, p. Xirouchakis (2)
|
|
STC Dn, 54/1/2005, P.151
|
|
Keywords: Decision making methodology, Uncertainty, Environmental performance |
Abstract : A general fuzzy multicriteria decision aid method for
conceptual design is proposed. It is used for selecting the best
compromise alternative, among a finite set of design concepts,
considering environmental and economic performance. At the conceptual
design phase most of the environmental impact is committed, whereas at
that stage the design concepts are imprecisely defined and should be
selected based on multiple, often conflicting criteria. Three vacuum
cleaners, using different design principles for the dust storage, are
analyzed. The best compromise design alternative is selected,
considering trade offs between end-of-life profit and environmental
criteria.
|
|
A Hierarchical Co-Evolutionary Approach to Conceptual Design
|
|
Y. Jin, W. Li, S.C-Y. Lu (1)
|
|
STC Dn, 54/1/2005, P.155
|
|
Keywords: Conceptual design, design automation, genetic algorithm |
Abstract : Conceptual design is a key early activity of product
development. Limited understanding of conceptual design process and lack
of quantitative information at this stage of design pose difficulties on
effective support for concept generation and evaluation. In this paper,
a hierarchical co-evolutionary approach is proposed to support
conceptual design. In this approach, higher-level functions are
decomposed based on a set of grammar rules, and mappings between
functions and their solutions, or means, are realized through a
co-evolutionary computing process. The paper describes the details of
the approach. An example of designing a mechanical personal transporter
is presented to demonstrate the effectiveness of the proposed approach.
|
|
Defining Specifications for Custom Products: A Multi-Attribute Negotiation Approach
|
|
S.L. Chen, M.M. Tseng (1)
|
|
STC Dn, 54/1/2005, P.159
|
|
Keywords: Design, Customization, Specification |
Abstract : Defining product specifications so that customers? needs could
be well matched with suppliers? capabilities is a very challenging task
in custom product design. This research links technical requirements on
product design with product management issues and formulates
specification definition as multi-attribute negotiation. Specification
negotiation is modeled as an iterative process of give and take in
search of a mutually acceptable configuration. A negotiation support
system is developed based on a product configuration system to identify
among the multiple attributes what to give, what to take, and by how
much so as to facilitate specification negotiation operationally.
|
STC E |
|
Wear Behaviour and Tool Life of Wire-EDM-ed and Ground Carbide Punches
|
|
B. Lauwers (2), J.-P. Kruth (1), W. Eeraerts
|
|
STC E, 54/1/2005, P.163
|
|
Keywords: Wire EDM, Carbide, Punch Wear |
Abstract : This paper describes and discusses the wear behaviour and tool
life of a cemented carbide punch produced in eight different qualities.
Six samples covering a wide variety of EDM surface textures and surface
integrities are compared to the performance of two ground punches. All
punches have been tested on an industrial press. Burr height
measurements on the stamped material, used as an evaluation of tool
life, does not indicate significant influences of the production
process. A more detailed analysis of the punch surface after 1x106 punch
cycles shows the presence of different wear zones. The surface layer
influenced by the production process, either EDM or grinding, is
completely removed in the zones near the cutting edge.
|
|
Study on Factors Determining Limits of Minimum Machinable Size in Micro EDM
|
|
T. Kawakami, M. Kunieda (2)
|
|
STC E, 54/1/2005, P.167
|
|
Keywords: Micro EDM, Residual Stress, Micro Structure |
Abstract : This paper describes an investigation on factors determining
the limits of the minimum machinable diameter of micro rods obtained by
micro EDM. Possible factors which influence the limits are discharge
crater size, depth of heat affected zone, residual stress, and material
micro-structure. In this paper, the influences of residual stress and
material micro-structure were especially examined. For the negative
effects of residual stress, both residual stress already present prior
to machining and residual stress generated by machining itself were
investigated using tungsten and cemented tungsten carbide as micro-rod
workpiece materials. To determine the effects of material
micro-structure, the influence of tungsten carbide grain size on the
limits of minimum machinable diameter of cemented tungsten carbide rods
was investigated. Comparing the limits between poly-crystal tungsten and
mono-crystal tungsten, it was found that micro-machining characteristics
were affected significantly by the anisotropy of the mono-crystal tungsten.
|
|
Surface Finishing of Micropins Produced by WEDG
|
|
T. Masuzawa (1), M. Yamaguchi, M. Fujino
|
|
STC E, 54/1/2005, P.171
|
|
Keywords: EDM, Micromachining, Surface finishing |
Abstract : This paper presents a new method of surface finishing for
micropin products. Precision micropins thinner than ø100 µm can be
produced by WEDG (wire electrodischarge grinding). However, the surface
quality of the products is not sufficient for applications that require
mirrorlike surface and/or a surface without a heat-affected zone. A
succession of two processes, WEDG and lapping, is proposed and tested
for its feasibility. In order to ensure the control of the lapping
conditions, micropins were WEDGed and lapped on the same machine. The
wire electrode for WEDG was used as the lapping tool. A smooth,
craterless surface with Ra=18 nm was achieved.
|
|
Investigation of Nanoscale Electro Machining (nano-EM) in Dielectric Oil
|
|
A.P. Malshe, K. Virwani, K.P. Rajurkar (1), D. Deshpande
|
|
STC E, 54/1/2005, P.175
|
|
Keywords: Electrical discharge machining, scanning tunneling microscope, nanoscale |
Abstract : There is a great need to produce nanoscale features on diverse
and sometimes difficult-to-machine materials for electronic and
bio-medical applications. This paper describes an electro machining (EM)
process at nanoscale, implemented using a scanning probe
platinum-iridium (Pt-Ir) electrode tool (15-20 nm radius) in dielectric
oil. The experiments were conducted by maintaining a gap of 2 nm between
the tool and the work-piece. These experiments have successfully
demonstrated that controlled and consistent machined features, as small
as 10 nm in diameter, on atomically flat gold can be obtained. It is
suggested that resonant tunnelling through dielectric oil molecules
causes the removal of material.
|
|
Temperature Measurement in Laser Forming of Sheet Metal
|
|
T. Ueda (2), E. Sentoku, K. Yamada, A. Hosokawa
|
|
STC E, 54/1/2005, P.179
|
|
Keywords: Laser beam machining, Bending, Temperature |
Abstract : Laser forming is a thermal process for the deformation of
sheet metal by thermal stress. Temperature distribution is the most
important factor for determining the bending angle of the sheet metal.
In the present study, the combined effect of the temperature of the
workpiece, the temperature gradient between the two surfaces of the
sheet, the size of the zone irradiated with laser beam, and the
thickness of the workpiece is investigated both theoretically and
experimentally. The temperature at the surface irradiated with CO2 laser
and at the opposite surface are simultaneously measured using two-color
pyrometers with an optical fiber. The bending angle has been found to
increase with the spot diameter and workpiece surface temperature and
decrease with workpiece thickness. The work surface temperature can be
used as a monitoring signal for the purpose of controlling the bending
angle.
|
|
Grit Blast Assisted Laser Milling/Grooving of Metallic Alloys
|
|
L. Li (2), J.J.Kim, M.H.A.Shukor
|
|
STC E, 54/1/2005, P.183
|
|
Keywords: Laser, machining, powder |
Abstract : Laser machining and milling of metallic alloys and ceramics
have been previously carried out by either direct vaporisation or assist
gas ejection of laser-melted materials. For certain metallic materials,
due to the high viscosity of the materials in the molten state, it is
difficult to achieve a clean cut. Recast and heat affected zones are
normally formed. This paper reports a hybrid process combining a grit
blasting and laser melting for the milling and grooving of stainless
steel, mild steel and titanium alloys. The work shows that up to 100%37;
increase in material removal rate and 15%37; reduction in the heat affected
zone size can be achieved compared with a gas jet assisted laser
machining process under the same operating conditions. Surface roughness
has been reduced by 60%37;. The effect of particle injection angle,
direction on material removal rate is presented. A critical particle
injection angle is established.
|
|
The causes and prevention of smut on etched AISI 300 stainless steels
|
|
D.M. Allen (2), H.J.A. Almond, F. Gaben, S. Impey
|
|
STC E, 54/1/2005, P.187
|
|
Keywords: Photochemical machining, stainless steel, smut |
Abstract : During the fabrication of stainless steel parts by
photochemical machining (PCM), a seemingly random occurrence of a
partially-adherent, brown/black deposit, known as smut, can occur. This
quality problem has plagued the PCM industry for over 30 years. In the
past, the problem has been attributed to "poor etch-quality" stainless
steel. However, an extensive investigation by the authors, comprising
some 7 person-years of effort, has established that while the metallurgy
of the stainless steel has some influence on the formation of smut, by
far the most important factor is the condition of the ferric chloride
etchant used for etching the parts. The influences of etchant
concentration, free hydrochloric acid content, temperature, atmosphere
and hydrodynamic flow have now been assessed quantitatively for the
first time. The investigation has led to the development of a theory
outlining the causes of smut formation, thus providing solutions for its
prevention.
|
|
Micro Electrochemical Machining of 3D Microstructure Using Dilute Sulfuric Acid
|
|
B.H. Kim, C.W. Na, Y.S. Lee, D.K. Choi, C.N. Chu (2)
|
|
STC E, 54/1/2005, P.191
|
|
Keywords: Electro chemical machining (ECM), Electrode, Micro machining |
Abstract : In this paper, micro electro chemical machining (ECM) using
ultra short pulses with tens of nanosecond duration is presented. Dilute
electrolyte, 0.1 M sulfuric acid was used and 3D micro-structures with
good surface quality were machined on stainless steel. By using a micro
electrode with less than 50 micrometer diameter, micro holes and micro
hemisphere with 60 micrometer diameter were machined. In ECM, the
increase in the machining depth causes taper of structures. To prevent
the taper, a disk-type electrode was introduced. Using the disk-type
electrode, the taper can be virtually eliminated. To improve
productivity, multiple electrodes were applied and several structures
were machined simultaneously. The ends of multiple electrodes were
machined to disk-shape for prevention of taper. Because the wear of tool
electrode is negligible in ECM, micro wire can be used as tool
electrode. Using a platinum wire electrode with 10 micrometer diameter,
stainless steel plate was machined similar to wire EDM process. By wire
ECM, micro grooves with 22 micrometer width were machined without wire
feeding.
|
|
Temperature Effects in Ultrasonic Cutting of Natural Materials
|
|
M. Lucas (2), A. Cardoni, A. MacBeath
|
|
STC E, 54/1/2005, P.195
|
|
Keywords: Ultrasonic, Cutting, Temperature |
Abstract : This paper investigates the relationship between ultrasonic
cutting parameters and temperature around the cutting site for wood and
bone, with the aim of reducing thermal damage in natural materials. Two
ultrasonic cutting blades, tuned at two different frequencies but with
identical cutting edge and surface profiles, are used in the
experiments. Temperature is monitored close to the cutting site and the
effects of applied load and blade tip vibration velocity are studied.
Results indicate that ultrasonic cutting blade design can incorporate
cutting parameters to reduce or eliminate thermal damage in these
natural materials without using an additional blade cooling system.
|
STC F |
|
Combined tube and double sheet hydroforming for the manufacturing of complex parts
|
|
M. Merklein, M. Geiger (1), M. Celeghini
|
|
STC F, 54/1/2005, P.199
|
|
Keywords: Hydroforming, sheet metal, tube |
Abstract : Modern lightweight construction, especially in the
automotive industry, requires more and more complex components, which
can be manufactured in one process step using the hydroforming
technology. The combination of the tube and double sheet hydroforming is
a new forming process, where a tube and two blanks are formed
simultaneously in a die cavity, combining the advantages of both
hydroforming variants. This paper deals with the fundamental
considerations and investigations related to connection between tube and
double sheet. The finite element analysis and laboratory trials were
used in order to design the shape of the die cavity and to avoid
wrinkles, material tearing and the collapse of the tube section during
forming. The paper will also illustrate an analytical model for the
prediction of the edge shape in the constrained bulging of a rectangular
cup together with several technical solutions, which enabled a complete
forming of the investigated part. Finally, the definition of a
hydroforming material factor based on the analytical model of the
hydraulic bulging process enables the right choice of sheets with
different material strength and thickness for the hydroforming of hybrid
components.
|
|
Bulge Testing under Constant and Variable Strain Rates of Superplastic Aluminium Alloys
|
|
D. Banabic, M. Vulcan /K. Siegert (1)
|
|
STC F, 54/1/2005, P.205
|
|
Keywords: Superplasticity, Formability, Sheet Metal Forming, Aluminium Alloys |
Abstract : The present paper deals with superplastic forming of aluminium
alloy AA5083 sheet metals tested at specific strain rates, temperatures
and counter pressures by means of bulge testing using circular and
elliptical dies and by the cone-cup testing method. Further, differences
from batch to batch can lead to a different strain rates at the maximum
m value. It is shown by experimental investigations that pulsating
strain rates can lead to higher m values and to increased thickness strains.
|
|
Warm and Hot Stamping of Ultra High Tensile Strength Steel Sheets Using Resistance Heating
|
|
K. Mori (2), S. Maki, Y. Tanaka
|
|
STC F, 54/1/2005, P.209
|
|
Keywords: Warm and hot forming, Sheet metal, Ultra high tensile strength steel |
Abstract : A warm and hot stamping process of ultra high tensile strength
steel sheets using resistance heating was developed to improve
springback and formability. In this process, the decrease in temperature
of the sheet before the forming is prevented by directly heating the
sheets set into the dies by means of the electrical resistance, the
so-called Joule heat. Since the heating time up to 800?C is only 2
seconds, the resistance heating is rapid enough to synchronise with a
press. The effects of the heating temperature on the springback and
formability of ultra high tensile strength steel sheets were examined.
The springback in hat-shaped bending of the high tensile strength steel
sheets was eliminated by heating the sheet. In addition, the ultra sheet
having a tensile strength of 980MPa was successfully drawn by the
heating. The heating temperature is optimum around 600?C due to the
small springback and oxidation and the increase in hardness.
|
|
Springback of High-Strength Steel after Hot and Warm Sheet Formings
|
|
J. Yanagimoto, K. Oyamada /T. Nakagawa (1)
|
|
STC F, 54/1/2005, P.213
|
|
Keywords: Sheet metal, Springback, FEM, Bending, Hot sheet forming, Warm sheet forming, Recrystallization |
Abstract : The springback of high-strength steel after hot and warm sheet
formings is investigated. Environmentally friendly vehicles will promote
the increasing usage of high-strength steel sheets, however, a large
amount of springback after sheet forming is one of the major drawbacks.
A series of hot and warm sheet forming experiments on high-strength
steel sheets are conducted using a hot compression testing machine, and
the effect of forming temperature on the amount of springback is
evaluated. The springback is markedly reduced when the forming
temperature is higher than 750K, which is approximately the critical
temperature for the recrystallization of ferrite grains.
|
|
Advanced Wear Simulation in Sheet Metal Forming
|
|
H. Hoffmann (2), C. Hwang, K. Ersoy
|
|
STC F, 54/1/2005, P.217
|
|
Keywords: Deep drawing, Simulation, Wear |
Abstract : A drawback of former wear simulation of deep drawing processes
is that the change of wear caused by increasing the number of punch
strokes was not considered. Geometry-Update-Scheme (GUS) which has been
proposed at Institute of Metal Forming and Casting considers the changes
of tool geometry caused by wear through interactive iterations of
forming and wear simulation. The wear depth from simulation using GUS
shows maximal 0.07 mm of difference from the measurement at a section of
worn die-geometry. In this study, only the abrasive wear was considered.
|
|
An Incremental Roll Forming Process for Manufacturing Doubly Curved Sheets from General Quadrilateral Sheet Blanks with Enhanced Process Features
|
|
S.J. Yoon, D.Y. Yang (1)
|
|
STC F, 54/1/2005, P.221
|
|
Keywords: Sheet metal, Roll, Incremental forming |
Abstract : In order to manufacture a doubly curved sheet metal
effectively, a flexible incremental roll forming process has been
developed by adopting the advantages of the incremental forming process
and the roll forming process by combining inherent flexibility of the
incremental forming process and continuous deformation of the roll
forming process. In the proposed roll forming system, a newly designed
gripper system is attached in order to achieve automation and more
precision manufacturing of the required sheet intended double curvature.
The forming method has been further enhanced to form general
quadrilateral blanks (including a square, a rectangle, a symmetrical
trapezoid and an asymmetrical trapezoid, etc.) into doubly curved shapes
by controlling the forming schedule developed by various experiments.
|
|
Analysis of Process Parameters and Forming Mechanisms within the Electromagnetic Forming Process
|
|
M. Kleiner (2), C. Beerwald, W. Homberg
|
|
STC F, 54/1/2005, P.225
|
|
Keywords: High Speed Forming, Process Planning, Forming Mechanism |
Abstract : Electromagnetic forming (EMF) is a typical high speed forming
process using the energy density of a pulsed magnetic field to form
workpieces made of metals with high electrical conductivity like e.g.
aluminium. In view of new lightweight constructions, special forming
processes like EMF gain importance for the associated materials. For a
better understanding of the working mechanisms and the process
prediction a coupling of electromagnetical and structure-mechanical
models, advanced simulation tools as well as detailed experimental
investigations with on-line measurements of the ultra-fast deformation
of significant workpiece areas is required. New results of research
concerning correlations among workpiece properties, strain rate, and
acting magnetic pressure are presented.
|
|
Real-Time Prediction of Geometrical Distortions of Hot-Rolled Steel Rings during Cooling
|
|
S. Bruschi, S. Casotto, T. Dal Negro (2), P.F. Bariani (1)
|
|
STC F, 54/1/2005, P.229
|
|
Keywords: Rolling, Cooling, Neural Network |
Abstract : The paper deals with the application of neural network
modelling to the real-time prediction of the geometrical distortion of
hot rolled steel rings during cooling from rolling to room temperature.
The neural network model was designed and developed to be part of a new
modular system for the in-line monitoring and real-time control of the
geometrical quality of rings, even those with a complex profile, during
hot and warm ring rolling operations. The data utilised to train the
neural network were generated by numerical simulations of the cooling
phase. In order to do these simulations, an FE model capable of coupling
thermal, mechanical and metalllurgical events was accurately calibrated.
The proposed model was then applied to an industrial case that is
described in the paper.
|
|
The Technical and Commercial Potential of an Incremental Ring Rolling Process
|
|
J.M. Allwood, R. Kopp (1), D. Michels, O. Music, M. öztop, T.F. Stanistreet, A.E. Tekkaya (2),
|
|
STC F, 54/1/2005, P.233
|
|
Keywords: Flexible, Rolling, Rings |
Abstract : A novel incremental ring rolling process is proposed, in which
a narrow mandrel is moved both radially and axially. The process has
potential to allow flexible near-net-shape forming of both hot and cold
rings, and has been assessed by experiments on commercial cold ring
rolling machines, a physical simulation using wax rings, and two finite
element models. The results suggest that the process is technically
feasible although the cycle time increases with the degree of
flexibility and the stability of deformation depends on careful design
of the tool path.
|
|
Finite Element Modeling of Roller Burnishing Process
|
|
Y.C. Yen, p. Sartkulvanich, T. Altan (1)
|
|
STC F, 54/1/2005, P.237
|
|
Keywords: Roller, Finite Element Method (FEM), Burnishing |
Abstract : Hard roller burnishing is a cost effective surface enhancement
process where a ceramic ball rolls on the machined surface under a high
pressure and flattens the roughness peaks. It not only improves surface
finish but also imposes favorable compressive residual stresses and
raises hardness in functional surfaces, which can lead to long fatigue
life. Most research in the past focused on experimental studies. There
is still a special need for a reliable finite element (FEM) model that
provides a fundamental understanding of the process mechanics. In this
study, 2D and 3D FEM models for hard roller burnishing were established.
The simulation results (i.e. surface deformation and residual stress)
were evaluated and compared between initial hard turned and burnished
surfaces. The predicted residual stress was validated with the
experimental data obtained from the literature.
|
|
Spin Extrusion - A New Partial Forming Technology based on 7 NC-Axes Machining
|
|
R. Neugebauer (2), R. Glass, M. Hoffmann
|
|
STC F, 54/1/2005, P.241
|
|
Keywords: Forming, Computer numerical control, quality assurance |
Abstract : Hollow shape component approaches, applied to shafts and
similar workpieces, represent a major potential for ground-breaking
innovations in lightweight engineering and safety designs. Among
suitable forming tech-nologies, spin extrusion is a pioneering and
particularly flexible hollow-shaping technique. All outside form
elements, straight or stepped cylinders, cones or spherical rotation
elements emerge just from the kinematics of tools. The inside hollow
shapes, as e.g. circular cross-sections, shaft to collar connections
such as spherical triangles, polygons, splines or dovetail forms are
manufactured with a shaping mandrel. Spin extrusion can be applied first
and foremost at dimensions that are unattainable with other techniques.
The application includes hollow shafts, thick-walled cups and
semi-finished tubular products that are not to be found in off-the-shelf
cross-sections. In these cases the possibility for using of massive bars
is connected with very high price advantages. Furthermore
material-saving machining is attracting special attention for high-grade
materials. The paper characterizes substantial steps of process analysis
and the appliance of a new, derived from the bound method, numerical
simulation method for spin extrusion process. Holistic process analysis
is the prime factor for process capability. The specific application of
the developed special methods of simulation, the accumulation of process
data and the integrating into the Computer numerical control of spin
extrusion machine is a precondition guaranteeing high-quality assurance.
|
|
Precision Extrusion Methods with Double Axis Servo-Press using Counter Pressure
|
|
K. Osakada (1), R. Matsumoto, M. Otsu, S. Hanami
|
|
STC F, 54/1/2005, P.245
|
|
Keywords: Cold, Extrusion, Servo-Press |
Abstract : Cold extrusion methods for manufacturing products with high
dimensional accuracy utilizing a servo-controlled press are studied.
Experiments using lead as a model material are carried out on a
servo-controlled double axis press against a flat tool supported by
counter pressure. The proposed extrusion methods are analysed with the
rigid-plastic finite element simulation by accommodating the
pressure-supported tool. It is found that a counter pressure of 50-60 %37;
of the flow stress is needed to flatten the front surfaces of the
extruded part. To obtain a long extruded part without under-filling
defect at the front corner, reverse extrusion is carried out by pushing
back the extruded part after forward-backward extrusion. The proposed
extrusion methods are verified with gear parts.
|
|
Analytical Approach to Elimination of Surface Micro-Defects in Forging
|
|
T. Ishikawa, N. Yukawa, Y. Yoshida, Y. Tozawa (1)
|
|
STC F, 54/1/2005, P.249
|
|
Keywords: Defect, FEM, Forging |
Abstract : Initial surface micro-scratches due to cropping, rolling or
handling change that cause crack or lap defects during forging and
reduce the quality of forged products. Elimination of surface
micro-defects in forging is pressing problem in forging industry. A new
method of finite element analysis featuring effective meshing and an
adaptive remeshing system is applied to clarify the mechanism of the
formation or the disappearance of surface micro-defects in forging.
V-shaped and rectangular scratches on the surface of billet are
simulated under the axisymmetric assumption and the basic deformation of
scratch during upsetting and the influence of friction on the
deformation of micro-defects are discussed. Shallow V-shaped scratch on
the top surface of billet tends to disappear and deep scratch becomes
lap defect during upsetting. Defects are more likely to disappear under
low friction. It is possible to predict that an initial surface
micro-scratch on the billet remain or not as a defect after forging.
|
|
Physiothermodynamics of Lubricant Deposition on Hot Die Surfaces
|
|
L. Yang, C. Liu, R. Shivpuri (2)
|
|
STC F, 54/1/2005, P.253
|
|
Keywords: Lubrication, Die, Surface |
Abstract : This paper presents a methodology for studying lubricant
behaviour during spraying on hot die surfaces. It consists of a single
droplet test to study the thermo-physical phenomena and a ?similitude?
based approach to extend the results to geometrically complex nozzle
sprays. This methodology is applied to the published results on the
cooling of hot forging die surfaces and is found to predict both the
magnitude and trends reasonably well. It is observed that graphite in
water lubricants with high dilutions provide heat transfer coefficients
similar to that of pure water while low dilutions provide lower
coefficients and longer dryoff times.
|
|
Semi-Solid Forging of 100Cr6 and X210CrW12 Steel
|
|
R. Kopp (1), G. Hirt, H. Shimahara, I. Seidl, F. Küthe, D. Abel, A. Schönbohm
|
|
STC F, 54/1/2005, P.257
|
|
Keywords: Semi-Solid, Forging, Rheocasting |
Abstract : Semi-solid forging of the steel grades 100Cr6 and X210CrW12
reveals advantages compared to conventional shape-giving process
technologies like casting and forging. These advantages result from the
thixotropic flow behaviour prevailing when suitable microstructure
parameters have been adjusted. Steel components with complex geometries
can be semi-solid forged to near net-shape in one single forming
operation. Two different strategies to generate a semi-solid precursor
material are investigated and compared with respect to their technical
and economic potential. With the first strategy conventional rod
material is inductively heated into the desired state and subsequently
forged using a fully automated unit. The second strategy consists of
producing the semi-solid precursor material directly from the liquid
state starting with a slightly overheated melt with subsequent means of
forced nucleation on a cooling slope. The semi-solid forging operation
is performed using an industrial 6,3MN hydraulic forging press and a
specific die design which provides the possibility to combine the
advantages of different tool materials such as metals coated with thin
ceramic layers and monolithic ceramics. The axial symmetrical geometry
of the processed steel parts favours the thermal-mechanical simulation
of the forging operation. The results of the experimental work are
presented and an outlook to both process variants is given.
|
|
Punching of Ultra Small Size Hole Array
|
|
S.H. Rhim, Y.K. Son, S.I. Oh (1)
|
|
STC F, 54/1/2005, P.261
|
|
Keywords: Ultra small hole array, Punching, Wafer die |
Abstract : This paper presents a method by which multiple holes of ultra
small size can be punched simultaneously. Silicon wafers were used to
fabricate punching die. Workpiece used in the present investigation were
the rolled pure copper of 3µm in thickness and CP titanium of 1.5µm in
thickness. The metal foils were punched with the dies and arrays of
circular and rectangular holes were made. The diameter of holes ranges
from 2-10µm. The process set-up is similar to that of the flexible
rubber pad forming or Guerin process. Arrays of holes were punched
successfully in one step forming. The punched holes were examined in
terms of their dimensions, surface qualities, and potential defect. The
effects of the die hole dimension on ultra small size hole formation of
the thin foil were discussed. The optimum process condition such as
proper die shape and diameter-thickness ratio (d/t) were also discussed.
The results in this paper show that the present method can be
successfully applied to the fabrication of ultra small size hole array
in a one step operation.
|
|
A new approach to determine press stiffness
|
|
M. Arentoft, T. Wanheim (1)
|
|
STC F, 54/1/2005, P.265
|
|
Keywords: Press, Precision, Forming |
Abstract : In precision forging processes any deviation from symmetric
conditions causes eccentric loads on the press e.q. multi step processes
or non symmetric components. This results in non-parallel positioning of
upper and lower press table leading to reduced accuracy and loss of
tolerances. The deflections of the press are a result of the reaction
force and the combined stiffness of the workpiece-die-press system which
is changing during the process. The press stiffness is described in
several classical books on metal forming, however, the forging industry
neither has an adequate technique to measure and characterize press
stiffness nor reliable methods to predict interactions that occur in a
combined work piece die press system. This work proposes a new procedure
for measuring press stiffness, which includes purely horizontal or
vertical loading of the press. The vertical and horizontal load can be
eccentrically positioned. Two loading devices and corresponding
measuring equipment for registration of press deflections are designed.
The press stiffness is presented as 6 by 6 flexibility matrix, which has
been described in existing literature. The approach has been tested by
measuring the stiffness of two hydraulic presses at 500 and 1000 t and a
1000 t mechanical press. Deflections in the size of several 1/10-mm are
identified. The work is supported by the European Commission.
|
STC G |
|
Analysis of Grinding Strategies Applied to Crankshaft Manufacturing
|
|
J.F.G. Oliveira (2), E.J. Silva. J.J.F. Gomes, F. Klocke (1), D. Friedrich
|
|
STC G, 54/1/2005, P.269
|
|
Keywords: Form Grinding; High Speed; CBN |
Abstract : A critical step in the manufacture of forged crankshafts is
the grinding of the sidewalls. The present research investigation was
undertaken to evaluate strategies for high-speed CBN grinding of
crankshafts sidewalls. Three strategies were analytically and
experimentally compared: axial plunge grinding, axial face grinding, and
multi-step axial face grinding. While all three strategies could produce
acceptable parts, the multi-step face grinding strategy was found to be
particularly advantageous for providing flexibility in the process control.
|
|
Practical Application of New Simulation Methods for the Elimination of Geometric Instabilities in Centerless Grinding
|
|
R. Lizarralde, D. Barrenetxea, I. Gallego, J.I. Marquinez /R. Bueno (1)
|
|
STC G, 54/1/2005, P.273
|
|
Keywords: Centerless, Application, Geometric stability |
Abstract : Elimination of geometric lobing in centerless grinding has
been extensively investigated. Several models have been successfully
developed, but no practical tool has been implemented on machines to
ease the setting up of the machine to ensure stable conditions. This
paper describes a software tool which has been developed for setting up
and optimization of centerless plunge grinding processes to avoid
geometric instabilities. The software generates stability maps showing
the stable and non-stable geometric configurations and the number of
lobes generated in non-stable conditions. Complementary time domain
models quantitatively predict the evolution of the profile error for
each geometric configuration.
|
|
Evaluation of Factors Controlling CBN Abrasive Selection for Vitrified Bonded Wheels
|
|
M.P. Hitchiner (3), S.B. McSpadden /J.A.Webster (1)
|
|
STC G, 54/1/2005, P.277
|
|
Keywords: Cubic Boron Nitride (CBN), Grinding, Experimentation. |
Abstract : Grinding tests were made to investigate the impact of new CBN
grains becoming available through globalization. The study investigated
the effect of grit size distribution and toughness in standard and newly
developed vitrified bond systems. Tougher grits were found to require
the development of stronger bonds to obtain economic benefits. The
effect of observable and induced process variables was evaluated to
determine minimum levels of wheel wear required for repeatability. It
was found that micron levels of process variability significantly
impacted wheel life.
|
|
Advances in High Performance Micro Abrasive Blasting
|
|
M. Achtsnick, A.M. Hoogstrate, B. Karpuschewski (2)
|
|
STC G, 54/1/2005, P.281
|
|
Keywords: Micromachining, Abrasion, Blasting |
Abstract : Micro abrasive blasting (MAB) has been successfully improved
by the introduction of a rectangular Laval nozzle concept. In this paper
the earlier presented set of models has been extended to predict the
performance of such nozzles. The results of the sub-model for the jet
show that its energy intensity is more evenly distributed and at a
substantial higher level compared to conventional nozzle concepts. The
results of the material removal sub-model show that it is more
beneficial to increase particle velocity rather than particle size to
increase the blasting efficiency. The developed sub-model for the
contour generation predicts the shape and the roughness of the blasting
profile. A scanning strategy has been developed which enables a
significant reduction of the processing time. The developed models have
been experimentally proved and verified. The knowledge gained in this
investigation opens the possibility to derive new rules for the design
of microstructures.
|
|
Modelling of Abrasive Waterjet Machining: A New Approach
|
|
M. ElTobgy, E-G Ng, M.A. Elbestawi (1)
|
|
STC G, 54/1/2005, P.285
|
|
Keywords: Abrasive, Water, Simulation |
Abstract : Abrasive waterjet (AWJ) machining is one of the recent
non-traditional methods starting to be used widely in industry for
material removal of different materials. The cutting performance of AWJ
is achieved by a very high speed, small-scale erosion process. In this
paper, a modified form of Finnie?s model for erosion is developed for
application to AWJ. This modified form is able to deal with curved
surfaces rather than flat surfaces only. Furthermore, the new modelling
approach is capable of simulating multiple particle erosion. This
approach uses standard material properties and requires no calibration
constants. The modelled results agreed well with both experimental and
analytical data.
|
|
Novel Kinematics for Cylindrical Grinding of Brittle Materials
|
|
P. Koshy, Y. Zhou, C. Guo (3), R. Chand /S. Malkin (1)
|
|
STC G, 54/1/2005, P.289
|
|
Keywords: Grinding, Anisotropy, Strength |
Abstract : Brittle materials are characterised by grinding direction
related strength anisotropy attributed to the dual population of
grinding induced microcracks. Surface grinding operations are therefore
implemented such that the grinding lay is along the direction of maximum
tensile stress in the component, which corresponds to minimal strength
degradation. The kinematic configuration of conventional machine tools
inherently precludes such an approach in cylindrical traverse grinding.
To this end, the paper presents aspects of an innovative
material-adapted kinematic variant, which corresponds to an enhancement
in characteristic flexural strength of about 30%37; as compared to
conventionally ground quartz samples.
|
|
Development of a Dicing Blade With Photopolymerizable Resins for Improving Machinability
|
|
S.B. Lee, Y. Tani (2), T. Enomoto, H. Sato (1)
|
|
STC G, 54/1/2005, P.293
|
|
Keywords: Grinding, Tool, Machinability |
Abstract : Dicing blades are widely used for the cutting of hard-brittle
materials such as ceramics, glass, and quartz. Thermosetting resin is
effective as a bonding agent in conventional blades. For production, it
takes several hours for heat curing by the hot press method and a
lapping process is also required for truing the blade flatness. These
result in blades with high cost. In this paper, the application of
photopolymerizable resin to the blade is proposed, for the purpose of
reducing production costs and improving machinability. Four types of
blade (a single layered, a three layered, a slotted and a slot-filled
blade) were used.As the result of a series of cutting tests on silicon
wafers, in comparison with the thermoset resin blade, the grinding
ratio, the spindle motor current and the chipping size distribution on
the workpiece surface, have been improved.
|
|
Slicing Process Monitoring of Quartz Glass Ferrules using Acoustic Emission
|
|
J.H. Ahn, S.R. Kim, H.Y. Kim, S.H. Kim, K.K. Cho (1)
|
|
STC G, 54/1/2005, P.297
|
|
Keywords: Monitoring, Acoustic, Glass ferrule |
Abstract : Inappropriate conditions and blade wear in the glass ferrule
slicing process are likely to cause chipping, scratching, and
inaccuracies in ferrules. To limit such abnormal occurrences, in-process
monitoring of the slicing process is necessary. The AE (Acoustic
Emission) signal is known to be a useful tool to detect cracks and
chippings in cutting brittle materials such as ceramics and glass,
because high-frequency acoustic waves are emitted in material fracture.
In this study, the glass ferrule slicing process was analyzed and
modeled in two stages ? cutting and polishing ? according to the
relative position of the blade and the glass rod. The AErms (root mean
square of AE) for various slicing cases, was acquired and investigated
both qualitatively and quantitatively based on the process model, the AE
feature was extracted for each abnormal state: the high-frequency
component of AE for chipping and the low-frequency component for wear.
In this paper, a monitoring algorithm using two index parameters ?
kurtosis and level ratio ? of AErms is proposed to discriminate abnormal
states ? chipping and wear ? in the glass ferrule slicing operation.
|
|
Development and Application of a Wheel Based Process Monitoring System in Grinding
|
|
E. Brinksmeier (1), C. Heinzel, L. Meyer
|
|
STC G, 54/1/2005, P.301
|
|
Keywords: Grinding, Process Monitoring, Surface Integrity |
Abstract : As an advantage to conventional monitoring systems sensor
equipped grinding wheels offer the possibility to gain information on
the process status from direct measurements of physical quantities in
the contact zone. This can be realized by the integration of small
temperature and force sensors into segmented grinding wheels. A new
thermocouple sensor concept was developed whose novelty is the
continuous contacting of the thermocouple by the grinding wheel wear.
Further tests where conducted using a piezoelectric sensor integrated
into the grinding wheel. By this set-up, forces in grinding as well as
in dressing processes were obtained. After assessing the system?s
capability for monitoring grinding and dressing processes tests in an
industrial environment showed the reliability of the monitoring system
which therefore may become the basis for a novel kind of process control
in the future.
|
|
An Intelligent Supervision System for Cylindrical Traverse Grinding
|
|
B.W. Kruszy?ski (2), P. Lajmert
|
|
STC G, 54/1/2005, P.305
|
|
Keywords: Control, Optimisation, Traverse grinding |
Abstract : The paper presents a supervision system that uses techniques
of artificial intelligence to monitor, control and optimise the traverse
grinding operation. The system consists of two levels which act in
parallel to produce parts satisfying the geometrical and surface finish
requirements with maximum possible productivity. The objective of the
first optimisation level is to maximize the material removal rate,
simultaneously satisfying restrictions on surface roughness,
out-of-roundness and waviness errors and on grinding temperature. At the
same time the second, geometrical control level is responsible for the
removal of the initial shape error by stabilising the motion trajectory
of the grinding wheel in relation to the part being ground. The
performance of the supervision system was evaluated by extensive
experiments to prove its effectiveness.
|
|
Pad Surface Roughness and Slurry Particle Size Distribution Effects on Material Removal Rate in Chemical Mechanical Planarization
|
|
C. Wang, p. Sherman, A. Chandra, D. Dornfeld (1)
|
|
STC G, 54/1/2005, P.309
|
|
Keywords: Modeling, Polishing, Statistical Distribution |
Abstract : The ability to predict material removal rates in
chemical mechanical planarization (CMP) is an essential ingredient for
low cost, high quality IC chips. Recently, models that address the
slurry particles have been proposed. We address three such models. The
first two differ only in how the number of active particles is computed.
Both assume that pad asperities are identical and nonrandom. The third
is dynamic in accommodating changing pad properties. For larger mean
particle size (diameter), the role of the standard deviation of particle
size distribution is uncertain. The dynamic behavior of the third model
is compared with experimental observations.
|
|
Characterisation of Burr Formation in Grinding and Prospects for Modelling
|
|
J.C. Aurich (2), H. Sudermann, H. Bil
|
|
STC G, 54/1/2005, P.313
|
|
Keywords: Grinding, Burr Formation, Descriptive Model |
Abstract : Increasing industrial requirements on the precision of edge
geometry lead to the investigation of burr formation, particularly in
finishing operations such as grinding. The objective of the presented
research is to understand the mechanisms of burr formation in grinding.
Following a description of previous research and existing approaches to
understand burr formation in grinding, experimental investigations in
flat surface grinding of tempered steel are described. Based on the
previous studies and the experimental results, a descriptive model of
burr formation in grinding is proposed.
|
STC M |
|
Innovative Machine Kinematics for Combined Handling and Machining of Three Dimensional Curved Lightweight Extrusion Structures
|
|
J. Fleischer, J.P. Schmidt-Ewig, H. Weule (1)
|
|
STC M, 54/1/2005, P.317
|
|
Keywords: Kinematic, Handling, Machining |
Abstract : The importance of rigid and self supporting space frame
structures for the automotive and aerospace industry continually
increases. To meet the market requirements for a flexible and
competitive small batch production, innovative machine concepts must be
investigated. By integrating handling and machining capabilities into
one machine structure, redundant degrees of freedom can be reduced and a
former idle economic potential can be made use of. This paper introduces
a systematic approach to reveal synergetic potentials that emerge by
integrating two different fields of function, the handling and the
machining. Therewith a matrix with technical solutions for a combination
of handling and machining is generated. These solutions are the base for
new machine concepts that fulfill both tasks with a minimal number of
machine axes. A detailed model of an innovative machine concept is
presented that allows a flexible and cost-efficient production of
three-dimensional curved extrusions.
|
|
Development of 3 DOF ultrasonic vibration tool for elliptical vibration cutting of sculptured surfaces
|
|
E. Shamoto (2), N. Suzuki, E. Tsuchiya, Y. Hori, H. Inagaki, K. Yoshino
|
|
STC M, 54/1/2005, P.321
|
|
Keywords: Cutting, Ultrasonic, Sculptured surface |
Abstract : A new machining method is proposed to obtain sculptured mirror
surfaces by applying elliptical vibration cutting. The tool is vibrated
elliptically, unlike rotating end mills, and is fed along the sculptured
surface in the proposed method. A 3 DOF ultrasonic vibration tool is
developed, which can generate an arbitrary ultrasonic elliptical
vibration in the 3D space so that it is suitable to machine the 3D
sculptured surfaces. A precision machine tool is also developed, and the
proposed method is successfully applied to mirror surface machining of
hardened die steel.
|
|
Development of Fixture Devices for Thin and Compliant Workpieces
|
|
T. Aoyama (2), Y. Kakinuma
|
|
STC M, 54/1/2005, P.325
|
|
Keywords: Fixture, Support, Workpiece |
Abstract : Fixturing of thin and compliant workpieces is in many ways
technically more demanding than fixturing of stiff workpieces. Nowadays,
thin and compliant workpieces, e.g., electrical parts containing
semiconductor substrates must be supported with uniform contact force in
order to assure high positioning accuracy. In particular, workpiece
supporters must suppress workpiece deformation during machining. This
study presents new fixture devices that can support thin and compliant
workpieces securely and minimize the deformation due to the machining
force. A low melting temperature alloy was used in the support structure
to fulfill the required functions with simple structure.
|
|
Improvement of Machining Accuracy of 5-Axis Control Ultraprecision Machining by Means of Laminarization and Mirror Surface Fininshing
|
|
T. Kawai, K. Ebihara, Y. Takeuchi (1)
|
|
STC M, 54/1/2005, P.329
|
|
Keywords: Ultraprecision, Micromachining, Accuracy |
Abstract : Air bearings are often used in ultraprecision machine tools
requiring high accuracy. With increasing the high accuracy for machine
tools, it is required to pay attention to microvibration with nanometer
order. The fluctuation in compressed air applied to air bearings causes
the air turbulence, which results in the microvibration. The study
presents the laminarization by the optimal design of piping and air
bearing surfaces as well as mirror surface finishing, so that the
laminarization can be realized to suppress the microvibration. From
experimental results, it is found that the surface roughness of
workpieces can be drastically improved by using a revised ultraprecision
machining center.
|
|
A Study on the Drive at Center of Gravity (DCG) Feed Principle and Its Application for Development of High Performance Machine Tool Systems
|
|
K. Hiramoto, A. Hansel, S. Ding, K. Yamazaki(1)
|
|
STC M, 54/1/2005, P.333
|
|
Keywords: Machine tool, Feed drive, Machining vibration |
Abstract : For high performance machining, it is essential to minimize
the vibration of a machine tool, which is incurred due to the
instantaneous acceleration/deceleration. To minimize this vibration, it
is fundamentally ideal to apply the driving force at the most
shock-insensitive position of the moving structure: the center of
gravity. Aiming at developing unparalleled high-performance machine tool
systems, the effectiveness of the Drive at the Center of Gravity (DCG)
principle on vibration reduction has been studied thoroughly by
analytical and experimental approaches. Based on the results obtained, a
new design of the high-performance machine tools has been discussed with
a special focus on the installation of DCG mechanism without sacrificing
any advantages already obtained in the recent basic design rules. The
paper also describes the comparative study between a machine tool based
on the DCG principle and the one with a conventional driving
configuration. The results obtained have shown a distinctive performance
difference in machining stability.
|
|
Development and Application of a Direct Drive Motor for Performance Enhancement of Versatile Machine Tool Systems
|
|
M. Mori (2), M. Fujishima, K. Kashihara, M. Horikawa
|
|
STC M, 54/1/2005, P.337
|
|
Keywords: Machine tool, High-speed indexing, High accuracy |
Abstract : For highly productive machining operations, multi-axis
versatile machine tools are drawing more attention in today?s market. In
order to maintain the stability and the motion accuracy over a long
operation time, it is important for such a versatile machine tool to
avoid complicated mechanisms, such as an indirect drive, from the
viewpoint of machine design. This paper presents a design methodology
for the specification of a direct drive (DD) motor to enhance the
overall performance of versatile machine tools. Practical application
examples to different types of machine tools are also presented.
|
|
A Concept for Shoe Last Manufacturing in Mass Customisation
|
|
B. Denkena (2), S. Scherger
|
|
STC M, 54/1/2005, P.341
|
|
Keywords: Customisation, Flexible manufacturing system (FMS), Automation |
Abstract : This paper presents a process chain development for the
production of shoe lasts for mass customised shoes. Shoe lasts are
moulds that manufacturers use for stretching the shoe leather and
applying the sole. The authors propose the complete manufacturing of
shoe lasts in only one machine with two clamping systems. During a first
phase the shoe last is clamped conventionally ? between centres. In a
second phase the last is clamped in the top region and the clamping dogs
that remain from the first phase can be removed. This new approach
reduces the number of process steps, is customised and reduces the
immense content of manual work. Although the single process steps are
carried out slower than in conventional shoe last industries the
complete manufacturing in one machine reduces the total production time
of one pair of shoe lasts and permits the economic production of single
pairs of lasts for mass customised shoes.
|
|
A New 3-DOF Spatial Parallel Mechanism for Milling Machines with Long X Travel
|
|
D.S. Milutinovic (2), M. Glavonjic, V. Kvrgic, S. Zivanovic
|
|
STC M, 54/1/2005, P.345
|
|
Keywords: Parallel mechanism, Modelling, Milling machine |
Abstract : It is well known that the shape and volume of the workspace
are one of the greatest weaknesses of parallel kinematic machine tools
(PKM). Hexaglide and Triaglide mechanisms are examples where workspace
extension is achieved by elongating one axis as a principal motion axis
that is a common feature of all Cartesian machines. With the idea of
principal axis of motion in mind, a new 3-DOF spatial parallel mechanism
for horizontal and vertical milling machines has been developed. In
comparison with similar developed mechanisms it has several advantages
such as: rather regular shape of the workspace (slightly modified block)
similar to serial machines; greater stiffness by nature of the struts
arrangement; good force and speed ratio through the entire mechanism?s
workspace. The paper describes the structure of the mechanism, modelling
approach and simulation on a developed vertical milling machine prototype.
|
|
Singularity Prediction for Parallel Robots for Improvement of Sensor-Integrated Assembly
|
|
J. Hesselbach (2), J. Maass, C. Bier
|
|
STC M, 54/1/2005, P.349
|
|
Keywords: Robot, Assembly, Singularity |
Abstract : The frequent occurrences of singularities inside a parallel
robot's workspace and in certain cases of sensor integration
non-deterministic end-effector trajectories demand a powerful online
singularity prediction and a control design that is capable of
displacing motion algorithms. The theory of a power-inspired index of
closeness to a singularity pose for parallel kinematic manipulators is
illumined and presented in this paper, supported by comparison to
Grassmann geometry and experimental results achieved on a HEXA robot. An
experimentally validated strategy for jerk bounded braking the
end-effector while approaching a singularity and an algorithm for
departing it again are presented as well.
|
|
Maximizing Chatter Free Material Removal Rate in Milling through Optimal Selection of Axial and Radial Depth of Cut Pairs
|
|
E. Budak (2), A. Tekeli
|
|
STC M, 54/1/2005, P.353
|
|
Keywords: Milling, Chatter, Material Removal Rate |
Abstract : Chatter vibrations in milling, which develop due to dynamic
interactions between the cutting tool and the workpiece, result in
reduced productivity and part quality. Several stability models have
been considered in previous publications, where mostly the stability
limit in terms of axial depth of cut is emphasized for chatter free
machining. In this paper, it is shown that, for the maximization of
chatter free material removal rate, radial depth of cut is of equal
importance. A method is proposed to determine the optimal combination of
depths of cut, so that chatter free material removal rate is maximized.
The application of the method is demonstrated on a pocketing example
where significant reduction in the machining time is obtained using the
optimal depths. The procedure can easily be integrated to a CAD/CAM
system or a virtual machining environment in order to identify the
optimal milling conditions.
|
|
importance. A method is proposed to determine the optimal
|
|
E. Govekar (2), J. Gradisek, M. Kalveram, T. Insperger, K. Weinert (1), G. Stepan, I. Grabec (1)
|
|
STC M, 54/1/2005, P.357
|
|
Keywords: End milling, Stability, Dynamics |
Abstract : Stability and dynamics of milling at small radial immersion
are investigated. Stability charts are predicted by the Semi
Discretization method. Two types of instability are predicted
corresponding to quasiperiodic and periodic chatter. The quasiperiodic
chatter lobes are open and distributed along the spindle speed axis
only, while the periodic chatter lobes are closed curves distributed in
the plane of spindle speed and depth of cut. Experiments confirm the
stability predictions, revealing the two principal types of chatter, the
bounded periodic chatter lobes, and some special chatter cases. The
recorded tool deflections in these cutting regimes are studied. The
experiments also show that the modal properties of a slender tool may
depend on spindle speed.
|
|
On the Influence of Drilling Depth Dependent Modal Damping on Chatter Vibration in BTA Deep Hole Drilling
|
|
K. Weinert (1), O. Webber, C. Peters
|
|
STC M, 54/1/2005, P.363
|
|
Keywords: Machining; Chatter; Deep Hole Drilling |
Abstract : BTA (Boring and Trepanning Association) deep hole drilling is
applied for machining bore holes with a high length to diameter ratio.
The slender tools involved make BTA processes highly susceptible to
chatter vibration. Chatter-free states and states with chatter vibration
corresponding to one of the first three torsional eigenfrequencies can
be observed to alternate during processes with constant cutting
parameters. A detailed FEA model of the significant BTA tool components
involved was developed. This takes into account the drilling depth
variant boundary conditions. Using this model, the state transitions can
be attributed to drilling depth dependent modal damping of the involved
torsional vibration modes.
|
|
Modelling the Vibratory Drilling Process to Foresee Cutting Parameters
|
|
H. Paris, S. Tichkiewitch (1), G. Peigné
|
|
STC M, 54/1/2005, P.367
|
|
Keywords: Drilling, Chatter, Self-excited vibration |
Abstract : The poor removal of chips in deep drilling of small diameter
is often the cause of tool breakage and poor quality surface. The
vibratory drilling enables the chip to be split thanks to the axial
vibrations of the drill self-maintained by the cutting energy. Therefore
chips are then evacuated easily. A specific tool holder with a variable
axial stiffness was developed by the authors. The amplitude of the
vibrations is greater than the feed rate. Vibratory drilling has been
modelled to predict the cutting conditions and the adjustment of the
stiffness of the tool holder. The models and the performances of the
self-excited vibratory drilling process were validated by an
experimental study.
|
|
A Model-Based Method to Develop PLC Software for Machine Tools
|
|
M.F. Zaeh, C. Poernbacher /J. Milberg (1)
|
|
STC M, 54/1/2005, P.371
|
|
Keywords: Concurrent engineering, Mechatronic, Virtual machine tool |
Abstract : It is difficult to develop PLC software for modern machine
tools due to their increasing functionality and the resulting
complexity. One approach to managing this is the model-based development
and simulation-aided verification of control software. A suitable method
for this is described in this paper. It focuses on a method for modeling
the control functionality and a simulation system for commissioning the
developed programs using a virtual model of the machine.
|
|
Open System Architecture for Drives
|
|
G. Pritschow (1), C. Kramer
|
|
STC M, 54/1/2005, P.375
|
|
Keywords: open architecture drive control |
Abstract : To meet the increasing demands of drive control in machine tools it is necessary to develop new and future-oriented drive control devices. In this paper we present a new platform for an Open System Architecture for Drives. This includes the specification of necessary hard- and software interfaces for the integration of new process and drive control, monitoring, diagnosis, and service functionalities and sensors.
|
|
Virtual Design and Optimization of Machine Tool Spindles
|
|
Y. Altintas(1), Y. Cao
|
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STC M, 54/1/2005, P.379
|
|
Keywords: Spindle, Cutting, Vibration |
Abstract : An integrated digital model of spindle, tool holder, tool and cutting process is presented. The spindle is modeled using an in-house developed Finite Element system. The preload on the bearings and the influence of gyroscopic and centrifugal forces from all rotating parts due to speed are considered. The bearing stiffness, mode shapes, Frequency Response Function at any point on the spindle can be predicted. The static and dynamic deflections along the spindle shaft as well as contact forces on the bearings can be predicted with simulated cutting forces before physically building and testing the spindles. The spacing of the bearings are optimized to achieve either maximum dynamics stiffness or maximum chatter free depth of cut at the desired speed region for a given cutter geometry and work-piece material. It is possible to add constraints to model mounting of the spindle on the machine tool, as well as defining local springs and damping elements at any nodal point on the spindle. The model is verified experimentally.
|
|
Ultrafast Tool Servos for Diamond Turning
|
|
X.-D Lu, D.L. Trumper (2)
|
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STC M, 54/1/2005, P.383
|
|
Keywords: Actuator, Mechatronic, Fast Tool Servo |
Abstract : This paper presents the design, implementation and control of
a new class of fast tool servos, based on a novel ultrafast motor
concept. A prototype ultrafast tool servo with a stroke of 30 mm is
described. Experimental results demonstrate that the ultrafast tool
servo achieves 23 kHz closed-loop bandwidth, as low as 1.7 nm RMS error,
500 G peak acceleration at 10 kHz open-loop operation, and 2.1 nm
(0.04%37;) error in tracking a 3 kHz sinusoid of 16 micrometer p-v. A 1 kW
linear power amplifier and a 1 MHz sampling rate high-speed real-time
computer are designed to drive and control this ultrafast tool servo. A
digital controller including loop shaping and adaptive feedforward
cancellation is designed to control the tool motion.
|
|
Electrohydraulic Active Damping System
|
|
C. Brecher, A. Schulz /M. Weck (1)
|
|
STC M, 54/1/2005, P.389
|
|
Keywords: Damping, Vibration, Control |
Abstract : A major characteristic of machine tools is the relative
dynamic flexibility at the tool centre point. Poorly damped resonance
frequencies often cause self-excited vibrations, so called chatter
vibrations, which dero-gate the machined surface and may cause tool
breakage. In practice, typically the metal removal rate and therefore
the productivity of the machine are reduced, in order to avoid such
vibrations. This paper deals with an active damping system for the
improvement of the dynamic flexibility of machine tools. The damping
sys-tem is based on an electrohydraulic actuator, which combines
comparatively large forces and a compact de-sign. The control input for
the actuator is determined from the acceleration measurement based on
the con-cept of a so-called velocity feedback control. In experimental
investigations, the depth of cut could almost be tripled.
|
|
New Control Techniques based on State Space Observers for improving the Precision and Dynamic Behaviour of Machine Tools
|
|
M. Zatarain (3), I. Ruiz de Argandoña, A. Illarramendi, J. L. Azpeitia, R. Bueno (1)
|
|
STC M, 54/1/2005, P.393
|
|
Keywords: Control, Dynamic Precision, Observer |
Abstract : This paper describes control techniques based on state space
observers that have been developed to improve the precision and dynamic
behaviour of machine tools. To improve precision, an accelerometer
located close to the tool centre point (TCP) is used, so that its
position is estimated by an state space observer and used as position
feedback instead of the position read by the linear scale. This way, the
structural deformation from the slide to the tool is compensated.
Dynamic behaviour is improved estimating the acceleration of the TCP by
the aforementioned observer and feeding this noiseless signal into the
control system, rather than the noisy signal of the accelerometer
itself. These techniques provide a simple way to achieve considerable
improvements without using complex and expensive TCP position
measurement devices. Tests on actual machines have shown that errors
produced by deflections between the slide and the TCP can be reduced by
70%37;.
|
|
A Hybrid Feature Recognizer for Machining Process Planning Systems
|
|
Y. Woo, E. Wang, Y.S. Kim, H.M. Rho (1)
|
|
STC M, 54/1/2005, P.397
|
|
Keywords: CAPP, CAM, Feature |
Abstract : We describe a hybrid feature recognition method for machining
features that integrates three distinct feature recognition methods:
graph matching, cell-based maximal volume decomposition, and negative
feature decomposition using convex decomposition. Each of these methods
has strengths and limitations, which are evaluated separately. We
integrate these methods in a sequential workflow, such that each method
recognizes features according to its strengths, and successively
simplifies the part model for the following methods. We identify two
anomalous cases in the application of maximal volume decomposition, and
their cure by introducing limiting halfspaces. Feature volumes
recognized by all three methods are then combined into a unified
hierarchical feature representation, which captures feature interaction
information, including geometry-based machining precedence relations.
|
STC O |
|
A Framework for Evaluating Production Policies to Improve Customer Responsiveness
|
|
S. Kurnaz, A. Cohn, Y. Koren (1)
|
|
STC O, 54/1/2005, P.401
|
|
Keywords: Manufacturing system, Operational flexibility, Responsiveness |
Abstract : Manufacturing systems are subject to both internal and
external disruptions. As a result, production sequences which appear
optimal during planning might be sub-optimal or even infeasible when
implemented. We therefore consider how manufacturers can trade off
anticipated completion time (makespan) against customer responsiveness
when making sequencing decisions. We first define a policy as a way to
control product sequencing in real time. We then present a framework for
evaluating different policies to assess their impact on customer
responsiveness. Finally, we demonstrate how this framework can be used
to analyze the link between sequencing, lot size, and update frequency.
|
|
Decision Making and Institutional Design for Product Lifecycle Management
|
|
K. Ueda (1), N. Nishino, H. Nakayama, S.H. Oda
|
|
STC O, 54/1/2005, P.407
|
|
Keywords: Lifecycle Management, Decision Making, Social Systems Engineering |
Abstract : This paper proposes a new approach to decision making and
institutional design for product lifecycle management based on social
systems engineering. Product lifecycle problems are limited not only by
technological issues, but also by economic and social issues. We
construct an agent-based model of decision making systems consisting of
human subjects such as producers, consumers, dismantlers and used-unit
dealers. The focal point of this study is the analysis of which economic
agents should collect used units and how product durability affects the
formation of a recycling society. This paper also presents discussion of
institutional design by comparing experimental results with current
institutions using real-world data for several types of products.
|
|
Modelling Dynamics of Autonomous Logistic Processes: Discrete-event versus Continuous Approaches
|
|
B. Scholz-Reiter (2), M. Freitag, C. de Beer, T. Jagalski
|
|
STC O, 54/1/2005, P.413
|
|
Keywords: Production, Control, Autonomy |
Abstract : For developing and benchmarking autonomous logistic processes,
dynamic models are essential. The paper investigates two different
modelling approaches regarding their abilities to describe an exemplary
scenario ? an autonomously controlled shop floor. A discrete-event
simulation model is compared to a continuous System Dynamics model. An
autonomous control strategy is developed and its effectiveness and
robustness are investigated by analysing the dynamic behaviour and the
logistic performance in cases of work load fluctuations and unexpected
disturbances.
|
|
Applying Simulation and Analytical Models for Logistic Performance Prediction
|
|
P. Nyhuis , G. von Cieminski, A. Fischer /K. Feldmann (1)
|
|
STC O, 54/1/2005, P.417
|
|
Keywords: Optimisation, Production, Management |
Abstract : Different types of models are used to describe the
interdependencies between logistic performance measures of production
systems in research and practice. The most widely known analytical
models in this field are queuing theory models. Simulation, on the other
hand, is a widespread technique for the exploration, design and
optimisation of complex production systems. Due to the limitations of
queuing and simulation models, a mathematical approximation approach
developed at the Institute of Production Systems and Logistics is
becoming more relevant: the Logistic Operating Curves. The paper
introduces the theory of these three modelling methods and compares as
well as differentiates them.
|
|
Electronic Commerce Negotiation in a Supply Chain Via Constraint Evaluation
|
|
R. Wilhelm (2), B. Chu, R. Sun
|
|
STC O, 54/1/2005, P.423
|
|
Keywords: Manufacturing, Constraint, Control |
Abstract : Negotiation is of critical importance in e-commerce
applications where the supply chain is dynamic and reconfiguring. In
this research supply chain negotiation problems are addressed as
constraint-satisfaction problems. In general each negotiation is handled
in the largest scope possible to avoid the sub-optimality that can
result from many local solutions. This global approach, however, must be
balanced with time constraints that apply in e-commerce supply chain
execution. In this paper, we describe a new approach for e-commerce
supply chain negotiation via constraint evaluation. As well, results
from prototype software, distributed across the internet, are discussed.
Beyond the general formulation, we describe a more particular problem of
kitted demand where a collection of purchased items must be acquired
within the same time horizon. To address slow convergence a time-based
penalty function is proposed.
|
|
Holonic Manufacturing Execution Systems
|
|
P. Valckenaers, H. Van Brussel (1)
|
|
STC O, 54/1/2005, P.427
|
|
Keywords: Holonic, Agent, Manufacturing execution system |
Abstract : This paper presents the design of a holonic manufacturing
execution system. The design is an instantiation of the PROSA reference
architecture augmented with coordination and control mechanisms inspired
by natural systems ? i.e. food foraging behavior in ant colonies.
Research prototypes are implemented as multiagent systems. The main
coordination and control mechanisms ensure that the process plans are
properly executed and emergently forecast the workload of the
manufacturing resources as well as well as lead times and routings of
the products. The design empowers the product instances to drive their
own production; the coordination is completely decentralized. In
contrast to many decentralized designs, the manufacturing execution
system predicts future behavior and proactively takes measures to
prevent impending problems from happening. A social control mechanism
ensures that product instances adhere sufficiently to their declared
intentions, which is necessary to guarantee adequate forecast accuracy.
The design has been applied to an industrial test case, and the paper
discusses results of this case study.
|
|
Production planning in reconfigurable enterprises and reconfigurable production systems
|
|
M. Bruccoleri, G. Lo Nigro, G. Perrone (2), P. Renna, S. Noto La Diega (1)
|
|
STC O, 54/1/2005, P.433
|
|
Keywords: Computer aided planning, Distributed manufacturing, Multi-agent system |
Abstract : Reconfigurable enterprises and reconfigurable production
systems represent nowadays one of the key re-sponses towards the
organisational and manufacturing needs arising in the new era known as
mass cus-tomization. The paper proposes an Agent Based approach for the
production planning activities in recon-figurable enterprises,
characterized by complex, articulated and geographically distributed
production ca-pacities contended by many product families and composed
by reconfigurable production systems that al-low quick adjustment of
production capacity and functionality consenting to manufacture
different products of the same part family.
|
|
A Conceptual Framework for Collaborative Design and Operations of Manufacturing Work Systems
|
|
A. Sluga, p. Butala, J. Peklenik (1)
|
|
STC O, 54/1/2005, P.437
|
|
Keywords: Manufacturing system, Distributed manufacturing, Virtual coordination |
Abstract : The paper addresses a conceptual framework for collaborative
product design and related manufacturing system development, operations
and maintenance. The framework consists of (1) a conceptual model for
collaboration among autonomous manufacturing work systems and (2) an ICT
platform which supports col-laborative operations over the web. The
framework improves visibility, understanding and control of the
proc-esses involved and on a practical level provides a platform on
which geographically distributed operations can be conducted
effectively. The system is developed as an integrated prototype web
application. The case study presents the implementation of the concept
in the development, operations and maintenance of manu-facturing cells
for die-casting of aluminum and magnesium components for automotive
industry.
|
|
A Decomposition Method to Support the Configuration/Reconfiguration of Production Systems
|
|
M. Colledani, T. Tolio (2)
|
|
STC O, 54/1/2005, P.441
|
|
Keywords: Performance Evaluation, Reconfigurable System, Decomposition Method |
Abstract : The configuration phase of a production system is
characterized by the need of evaluating a large number of system
alternatives. In this phase, a fast and reliable performance evaluation
tool able to analyze and explain the behaviour of the system is
necessary. The paper proposes an approximate analytical method based on
decomposition techniques for modelling and evaluating the performance of
production systems involving split and merge of production flows,
multiple products, buffers with finite capacity and
manufacturing/assembly/disassembly operations. The paper also reports
the application of the method to the performance evaluation and
reconfiguration of a real system producing white goods.
|
|
Manufacturing Systems Configuration Complexity
|
|
H.A. ElMaraghy (1), O. Kuzgunkaya, R.J. Urbanic
|
|
STC O, 54/1/2005, P.445
|
|
Keywords: Manufacturing Systems, Group Technology, Complexity |
Abstract : A new Complexity Coding System is introduced to classify and
code the machines, buffers and material handling equipment that make up
manufacturing systems. A code-based complexity index is proposed to
capture the amount and variety of information. Machining of a cylinder
block is used to demonstrate the application of the coding system and
complexity index in comparing five alternate manufacturing systems. The
probability of a manufacturing system success in delivering the desired
production capacity, as function of the availability of its components,
is used as an additional measure of the system complexity in meeting the
targeted forecast production volume with its variation.
|
|
Automated Tool Selection for Computer-Aided Process Planning in Sheet Metal Bending
|
|
J.R. Duflou (2), T.H.M. Nguyen, J.-P. Kruth (1), D. Cattrysse
|
|
STC O, 54/1/2005, P.451
|
|
Keywords: CAPP, Tooling, Bending |
Abstract : Bend sequencing and tool selection have long been the main
hurdles for achieving automatic process planning for sheet metal
bending. In this unique process, the complex shape and position
transitions of workpieces make it hard to obtain a collision-free
operation plan. The time-consuming involvement of human experts is often
required to solve more complex problems. This paper presents a tool
selection methodology to be integrated in the automatic bend sequencing
system discussed in previous work, therefore contributing to fully
automated process planning for bent sheet metal parts. Both the
described selection strategy and the related algorithms have been
implemented in an industrial software package. The results presented in
this paper, as illustrated by a number of case studies, demonstrate that
automatic process planning for sheet metal bending is feasible and that
the developed system provides well-optimised solutions with a reasonable
time complexity.
|
|
Design and Analysis of Closed-Loop Capacity Control for a Multi-Workstation Production System
|
|
J-H. Kim, N.A. Duffie (1)
|
|
STC O, 54/1/2005, P.455
|
|
Keywords: Production, Control, Analysis |
Abstract : In this paper, a model is described that represents the
dynamics of a multi-workstation production system that incorporates
closed-loop production planning and control. The model is used to
predict the response of the production system to work disturbances and
the propagation of disturbances through the system. Capacity control
designs are evaluated with respect to their removal of the effects of
work disturbances and response to changing capacity demands in upstream
workstations. Methods of control engineering are used to make the
analysis tractable, as well as improve understanding and control of
complex dynamic behavior.
|
|
Intelligent Tool Management in a Multiple Supplier Network
|
|
D. D'Addona, R. Teti (1)
|
|
STC O, 54/1/2005, P.459
|
|
Keywords: Tool management, Supply networks, Intelligent systems |
Abstract : The development and implementation of an intelligent Flexible
Tool Management Strategy (FTMS), based on Fuzzy Logic (FL) theory and
integrated in a Multi-Agent Tool Management System (MATMS) for automatic
tool procurement in a supply network, is presented. The MATMS operates
in the framework of a negotiation-based, multiple-supplier network where
a turbine blade producer requires dressing jobs on worn-out CBN grinding
wheels from external tool manufacturers. The main characteristics of the
intelligent FTMS approach is the use of fuzzy set theory to model the
uncertainty associated with tool demand rate and the employment of fuzzy
reasoning to expand the strategy operational flexibility in comparison
with traditional tool management and previously developed crisp FTMS
paradigms.
|
|
Service CAD System - Evaluation and Quantification -
|
|
T. Arai (1), Y. Shimomura
|
|
STC O, 54/1/2005, P.463
|
|
Keywords: CAD, Simulation, Service Engineerin |
Abstract : To develop services effectively and efficiently, a
computer-aided design system for service is essential. The authors have
proposed a prototype system of Service CAD called ?Service Explorer?.
Values of services are evaluated privately and subjectively by
consumers. Thus various design methodology such as QFD (Quality Function
Deployment) and AHP (Analytic Hierarchy Process) have been introduced to
evaluate the consumers' satisfaction. The new service CAD system is
installed and verified. The surveyed example of a set of service is
analyzed and the CAD system provides a set of new candidates of services.
|
STC P |
|
Nano-Position Sensing Using Optically Motion-controlled Microprobe with PSD Based on Laser Trapping Technique
|
|
Y. Takaya, K. Imai, S. Dejima, T. Miyoshi /N. Ikawa (1)
|
|
STC P, 54/1/2005, P.467
|
|
Keywords: Ultra-precision, Optical measurement, Nano-CMM |
Abstract : A position sensing microprobe has been developed which
satisfies harsh requirements to establish a nano-CMM (coordinate
measuring machine) proposed for measuring microparts with a target
accuracy of less than 50 nm within a 10 mm cubed working volume. This
paper deals with dynamic properties and position sensing accuracy of the
improved microprobe system for the nano-CMM using an optically trapped
probe sphere of 8.0 micrometer in diameter. The probe sphere is forced
to vibrate with about a hundred nanometer amplitude and high frequency
based on optical radiation pressure control. It is possible to measure
its dynamic motions with a higher accuracy using the newly developed
optical system with a position sensing detector (PSD). It is
experimentally suggested that the improved microprobe system can achieve
nano-position sensing in the lateral direction.
|
|
A Measuring Artefact for true 3D Machine Testing and Calibration
|
|
B. Bringmann, A. Küng /W. Knapp (1)
|
|
STC P, 54/1/2005, P.471
|
|
Keywords: Measuring instrument, Calibration, Uncertainty |
Abstract : A new measuring device is introduced that allows fast testing
and calibration of machine tools, robots and co-ordinate measuring
machines with three linear movements with a measurement uncertainty of
less than 5 µm. Errors are measured in the three degrees of freedom X,
Y, Z at measuring points forming a regular three di-mensional grid, thus
allowing space error compensation. The device consists of a standard 2D-
ball plate that can be relocated square to the plate. Kinematic
couplings ensure defined and repeatable relative locations of the ball
plate ? thus forming a three dimensional grid. The main concept, the
calibration of the kinematic arte-fact, the probing method and
uncertainty estimation are explained in the paper. The application of
the kine-matic artefact on a three axes machine tool is shown.
Measurement uncertainty and robustness against im-perfect environmental
conditions are very competitive compared to the current state of the art
in machine tool metrology.
|
|
Error mapping of CMMs and machine tools by a single tracking interferometer
|
|
H. Schwenke (2), M. Franke, J. Hannaford /H. Kunzmann (1)
|
|
STC P, 54/1/2005, P.475
|
|
Keywords: Coordinate Measuring Machine, Calibration, Kinematic error |
Abstract : This paper presents a novel approach for the mapping of
geometric errors of machine tools and coordinate measuring machines by a
single tracking interferometer. The concept is based on interferometric
displacement measurements between reference points that are fixed to the
base and offset points fixed to the machine head. The experimental
comparison with an independent technique on a high accuracy CMM
demonstrated the agreement of parameters in the sub-micron range. Thus,
the method proved to be suitable for the highest accuracy demands.
Furthermore, it has almost no limitation for the maximum size of the
working volume. It does not require any alignment of equipment and
yields a very simple data structure, which can be evaluated by the
developed software with very little additional information from the
operator. The method has also been tested on a large horizontal arm
machine and on a smaller high precision machine tool.
|
|
Comparison of Coordinate Measuring Machines using an Optomechanical Hole Plate
|
|
L. De Chiffre (1), H.N. Hansen (2), R.E. Morace
|
|
STC P, 54/1/2005, P.479
|
|
Keywords: Coordinate measuring machine (CMM), Optical measurement, Calibration |
Abstract : An interlaboratory comparison on mechanical and optical
coordinate measuring machines (CMMs) was carried out in the period from
August 2002 to November 2004. 15 different research laboratories were
involved from 9 countries, with a total of 23 CMMs (12 mechanical and 11
optical) being used to measure an optomechanical hole plate, designed
and manufactured by DTU, whereby it is possible to compare the
performance of measurements obtained optically and mechanically. The
comparison has shown that the optomechanical hole plate can be
calibrated, following a well-established procedure for ball plate
calibration, with uncertainties between 0.5 µm and 2 µm. Based on
results from the comparison, optical CMM measurements can be divided in
two groups. A group leading to deviations larger than 2 µm, and a group
with deviations that are comparable to those obtained with mechanical
machines. This comparison shows that optical coordinate measuring
machines, generally speaking, can be as good as mechanical ones.
|
|
Improving the Accuracy of Large Scale Monolithic Parts Using Fiducials
|
|
S. Smith (2), B.A. Woody, J.A. Miller
|
|
STC P, 54/1/2005, P.483
|
|
Keywords: Machining, Accuracy, Improvement |
Abstract : Monolithic machined components are rapidly replacing sheet
metal assemblies to reduce labor costs. As these monolithic parts become
larger, maintaining the accuracy required for further assembly
operations becomes difficult. The long-range accuracy and the thermal
environment of most machine tools become the limiting factors for part
size. This paper describes a solution to this problem using fiducials,
the spacing of which is based on the machine accuracy and part
tolerance. Experimental results demonstrate the validity of the
technique. This technique can be extended to allow small machines to
manufacture large components and is also applicable in high volume
manufacturing environments.
|
|
An Elastically Guided Machine Axis with Nanometer Repeatability
|
|
J.K.v.Seggelen, P.C.J.N. Rosielle, P.H.J. Schellekens (1), H.A.M. Spaan, R.H. Bergmans, G.J.W.L. Kot
|
|
STC P, 54/1/2005, P.487
|
|
Keywords: Coordinate measuring machine (CMM), Design, Calibration |
Abstract : This paper focuses on the on the design and calibration of an
elastically guided vertical axis that will be applied in a small high
precision 3D Coordinate Measuring Machine aiming a volumetric
uncertainty of 25 nm. The design part of this paper discusses the
principles of this system, the compensation of the stiffness of the
vertical axis in the direction of motion, the weight compensation method
and the design and performance of the axis precision drive system, a
Lorentz actuator. In the metrology part of this paper the calibration
methods to determine the linearity as well as motion straightness and
axis rotation errors are discussed. Finally first calibration results of
this axis show nanometer repeatability of the probing point over the 4
mm stroke of this axis. The causes of the short-term variations with a
bandwidth of about 10 nm are under investigation. Error compensation may
reduce the residual error of the probing point to the nanometer level.
|
|
A Laser Doppler Interferometric System for Measuring Motion of Vibrating Combs
|
|
G.X. Zhang (1), Y. Zhong, X. Hong, C.L. Leng, C.Z. Jiang, Z.H. Du, J.F. Ouyang
|
|
STC P, 54/1/2005, P.491
|
|
Keywords: Measurement, Motion, Micro-Electro-Mechanical System |
Abstract : Micro-Electro-Mechanical Systems have been growing rapidly
over recent years. However, measurement of their motions is a difficult
problem. A laser Doppler interferometric system for measuring motion
characteristics of vibrating combs in MEMS is presented. The working
principle and optical diagram of the system are explained. Some key
challenges in the system design are discussed. The velocity,
displacement, and frequency can be acquired by demodulating the
phase-modulated Doppler signal and processing the data by software.
|
|
Metrology and Calibration of a Long Travel Stage
|
|
C. Evans (1), M. Holmes, F. Demarest, D. Newton, A. Stein
|
|
STC P, 54/1/2005, P.495
|
|
Keywords: Metrology, interferometry, straightness |
Abstract : Nine axes of displacement measuring interferometers (DMIs)
provide feedback for the control of a six-degree of freedom stage with a
work volume of 500 x 1 x 1 mm. Four additional DMIs are used for
straightness and squareness calibration. Even with correction for
angular error motions, cosine errors combined with cyclic errors
compromise straightness calibration with a moving mirror configuration.
A Fizeau interferometer provides pitch and yaw measurement. Automatic
cyclic error compensation is demonstrated
|
|
A Portable Stereovision System for Cultural Heritage Monitoring
|
|
A. Balsamo (2), A. Chimienti, S. Desogus, p. Grattoni, A. Meda, R. Nerino, G. Pettiti, M.L. Rastello
|
|
STC P, 54/1/2005, P.499
|
|
Keywords: Optical, Measuring instrument, Geometric modelling |
Abstract : In a nation-wide project named SIINDA, a novel instrument was
developed and tested, intended for monitoring and diagnosing monuments.
The instrument ?named AVS? is portable to operate on field, and is
capable of measuring 3D and colorimetric coordinates simultaneously. The
paper describes the AVS, with a focus on its geometric measurement
capability. Particular attention is given to the software compensation
of the geometrical errors: the model is given, and the experimental plan
to derive the model parameters is described, including the artefact
designed and made for this purpose. Experimental results of laboratory
and of on field tests are reported.
|
STC S |
|
Surfaces of Calcium Fluoride Single Crystals Ground with an Ultra-Precision Surface Grinder
|
|
Y. Namba, T. Yoshida, S. Yoshida, K. Yoshida /K. Iwata (1)
|
|
STC S, 54/1/2005, P.503
|
|
Keywords: Ultra-precision grinding, Crystalline anisotropy, Calcium fluoride |
Abstract : Calcium fluoride single crystals for next-generation optical
lithography were fabricated with surfaces corresponding to the (001),
(111), and (110) crystalline planes. The grinding process utilized an
ultra-precision surface grinder and was optimized for resin-bonded
SD3000-75-B diamond wheels. A premium crystalline surface had a measured
surface roughness of 0.89 nm Ra, 6.99 nm Ry and 1.10 nm rms, with no
microcracks. We show that the surface roughness of these samples depends
on the crystalline plane and the orientation, as well as on the grinding
conditions. Measurement of the sub-surface damage layer and the
laser-induced damage threshold are also presented herewith.
|
|
Molecular Dynamics Simulation of Dimple Formation Process on Ductile Fracture Surface
|
|
T. Inamura(2), N. Takezawa, T. Miura, K. Yamada
|
|
STC S, 54/1/2005, P.507
|
|
Keywords: Cracking, Simulation, Defect |
Abstract : On the basis of the drawbacks of the existing theoretical
and/or simulation methods, a new coupled analytical/MD method has been
proposed to study void and dimple formation in the ductile fracture of a
defect-free monocrystal copper. The result of the simulation shows that
void and dimple formation in a defect-free monocrystal copper occurs,
first, through a phase change from a monocrystal structure to a
polycrystal structure, and then by a force system that produces relative
rotations of grains.
|
|
Investigation of Substrate Finishing Conditions to Improve Adhesive Strength of DLC Films
|
|
H. Ohmori (2), K. Katahira, J. Komotori, M. Mizutani, F. Maehama, M. Iwaki
|
|
STC S, 54/1/2005, P.511
|
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Keywords: Coating, Finishing Process, Electrical Grinding |
Abstract : This study investigated the effects of grinding wheels on the
surface modification properties in Electrolytic In-process Dressing
grinding. Three specimens were ground with different abrasive grinding
wheels: diamond wheel, SiO2 wheel, and diamond + SiO2 wheel. These three
different grinding wheels produced surfaces modified by the diffusion of
the abrasive elements. Adhesive strength evaluation tests between the
substrate surface and the DLC film were performed using micro-scratch
testing. The finished surface ground by the diamond + SiO2 wheel showed
the highest adhesive strength due to the physical and chemical
properties of the diffused elements. As a result, application of this
proposed grinding method to mold fabrication shows considerable promise.
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Surface Properties and Performance of Multilayer Coated Tools in Turning Inconel
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L. Settineri /R. Levi (1)
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STC S, 54/1/2005, P.515
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Keywords: Coating, Surface Analysis, Cutting Tool |
Abstract : Nanostructured coatings were developed in order to machine
nickel-based super-alloys in Minimum Quantity Lubrication (MQL), or dry
conditions. Three dedicated coatings, TiN+AlTiN, TiN+AlTiN+MoS2 and
CrN+CrN:C+C, applied by PVD on WC-Co inserts, developed nanostructured
layers exhibiting superior performance, as confirmed by laboratory tests
and machining experiments. Coatings surface qualification included,
among other tests, SEM observation with EDS analysis, nanoindentation
and scratch tests, classic tribological evaluation by ball-on-disk
set-up, surface texture analysis. Dry and MQL turning experiments show
substantial agreement with tribological and adhesion/toughness tests.
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Precision and surface integrity of threads obtained by form tapping
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G. Fromentin, G. Poulachon (2), A. Moisan (1), B. Julien, J. Giessler
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STC S, 54/1/2005, P.519
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Keywords: Cold form tapping, Surface properties, Assembly |
Abstract : Largely applied to internal threading of extruded tubes, cold
form tapping is now becoming a promising process for internal threading
of holes in non ferrous and ferrous solid components, more particularly
for mass production in the automotive industry. The aim of this study is
to present the surface properties of the threads resulting from form
tapping. Geometrical characterization, surface texture, mechanical and
metallurgical observations are investigated. The results obtained are
discussed according to the input parameters of the process, and are
compared to those obtained from cut tapping. The strength of the work
material and the influence of the lubricant are the two main parameters
affecting the process, and a correlation with the tapping torque is
proposed. Finally, the characteristics of the thread surface depend on
the parameters of the tapping operation, thus it has to be taken into
account in the design approach when this tapping process is chosen.
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Precise Alignment of Workpieces Using Speckle Patterns as Optical Fingerprints
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G. Goch (1), H. Prekel, S. Patzelt, M. Faravashi, F. Horn
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STC S, 54/1/2005, P.523
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Keywords: Workpiece alignment, Surface roughness, Speckle pattern |
Abstract : Engineering process chains sometimes require a precise
repositioning method of workpieces within production machines and
measuring devices. This causes difficulties, however, if the workpiece
may not be marked permanently in order to set up a sample coordinate
system. This paper presents a repositioning method based on the unique
statistical properties of monochromatic speckle patterns emerging from a
specific spot of a rough workpiece surface. The speckle pattern could be
regarded as an individual "fingerprint" of this specific surface spot.
The influence of the experimental parameters (laser wavelength, beam
diameter, wavefront curvature) on the uncertainty of relocation is
discussed.
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Dynamics and Control of Tapping Tip in Atomic Force Microscope for Surface Measurement Applications
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S.I. Lee, J.M. Lee (1), S.H. Hong
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STC S, 54/1/2005, P.527
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Keywords: Atomic force microscopy (AFM), Tapping mode, Nonlinear dynamics |
Abstract : In tapping mode atomic force microscopy (TM-AFM), the
vibro-contact response of a resonating tip is used to measure the
nanoscale topology and other properties of a sample surface. However,
the nonlinear tip-surface interactions can affect the tip response and
destabilize the tapping mode control. Especially it is difficult to
obtain a good scanned image of high adhesion surfaces such as polymers
and biomolecules using conventional tapping mode control. In this study,
theoretical and experimental investigations are made on the nonlinear
dynamics and control of TM-AFM. Also we report the surface adhesion is
an additional important parameter to determine the control stability of
TM-AFM. In addition, we prove that it is more adequate to use
Johnson-Kendall-Roberts (JKR) contact model to obtain a reasonable
tapping response in AFM for the soft and high adhesion samples.
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Modelling and Measurement Uncertainty Estimation for Integrated AFM-CMM Instrument
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H.N. Hansen (2), P. Bariani, L. De Chiffre (1)
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STC S, 54/1/2005, P.531
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Keywords: Atomic force microscopy (AFM), Coordinate measuring machine (CMM), Measurement uncertainty |
Abstract : This paper describes modelling of an integrated AFM - CMM
instrument, its calibration, and estimation of measurement uncertainty.
Positioning errors were seen to limit the instrument performance.
Software for off-line stitching of single AFM scans was developed and
verified, which allows compensation of such errors. A geometrical model
of the instrument was produced, describing the interaction between AFM
and CMM systematic errors. The model parameters were quantified through
calibration, and the model used for establishing an optimised
measurement procedure for surface mapping. A maximum uncertainty of 0.8%37;
was achieved for the case of surface mapping of 1.2x1.2 mm2 consisting
of 49 single AFM scanned areas.
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