Measurement Scheme Synthesis in Multi-Station Machining Systems

2004 ◽  
Vol 126 (1) ◽  
pp. 178-188 ◽  
Author(s):  
Dragan Djurdjanovic ◽  
Jun Ni
Keyword(s):  
Genetic Algorithm ◽  
Machining Process ◽  
Human Knowledge ◽  
Quantitative Characterization ◽  
Root Cause ◽  
Measurement Scheme ◽  
Machining Errors ◽  
Synthesis Procedure ◽  
Selection Of

Different sets of measurements carry different amounts of information about the root causes of quality problems in machining. The selection of measurements in multi-station machining systems is currently a slow and error-prone process based on expert human knowledge. In this paper, we propose systematic procedures for synthesizing measurement schemes that carry the most information about the root causes of dimensional machining errors. The amount of root cause information conveyed by a given set of measurements was assessed using the recently introduced formal methods for quantitative characterization of measurement schemes in multi-station machining systems. The newly proposed measurement scheme synthesis procedures were applied to devising measurement schemes in an automotive cylinder head machining process. It was observed that the measurement scheme synthesis procedure based on a genetic algorithm robustly outperformed the synthesis procedures based on the heuristics of successive measurement removal.

Measurement Scheme Synthesis in Multi-Station Machining Systems

Manufacturing ◽  
2002 ◽  
Author(s):  
Dragan Djurdjanovic ◽  
Jun Ni
Keyword(s):  
Genetic Algorithm ◽  
Formal Methods ◽  
Cylinder Head ◽  
Human Intervention ◽  
Quantitative Characterization ◽  
Measurement Scheme ◽  
Engine Cylinder ◽  
Synthesis Procedure ◽  
Selection Of

The selection of measurements in multi-station machining systems is currently not a systematic process and it involves expert human intervention. In this paper, the recently introduced formal methods for quantitative characterization of measurement schemes in multi-station machining systems are employed in devising systematic measurement scheme synthesis procedures. The newly proposed synthesis procedures were applied in devising measurement schemes in the process used to machine a car engine cylinder head. It was observed that the measurement scheme synthesis procedure based on a genetic algorithm robustly outperformed the synthesis procedures based on the heuristics of successive measurement removal.

scholarly journals Generation and characterization of ultra-precision compound freeform surfaces

2019 ◽  
Vol 103 (1) ◽  
pp. 003685041988011
Author(s):  
Lingbao Kong ◽  
Yingao Ma ◽  
Mingjun Ren ◽  
Min Xu ◽  
Chifai Cheung
Keyword(s):  
Tool Path ◽  
Complex Geometry ◽  
Experimental Studies ◽  
Machining Process ◽  
Freeform Surface ◽  
Freeform Surfaces ◽  
Machining Errors ◽  
Hybrid Machining Process ◽  
Ultra Precision

Compound freeform surfaces are widely used in bionic and optical applications. The manufacturing and measurement of such surfaces are challenging due to the complex geometry with multi-scale features in a high precision level with sub-micrometer form accuracy and nanometer surface finish. This article presents a study of ultra-precision machining and characterization of compound freeform surfaces. A hybrid machining process by combining slow slide servo and fast tool servo is proposed to machine compound freeform surfaces. The machining process for this hybrid tool servo is explained, and tool path generation is presented. Then, a normal template-based matching and characterization method is proposed to evaluate such compound freeform surfaces. Experimental studies are undertaken to machine a compound freeform surface using the proposed method based on a four-axis ultra-precision machine tool. The machined compound freeform surface is also measured and characterized by the proposed analysis and characterization method. The experimental results are presented, and the machining errors for compound freeform surfaces are also discussed.

Bayesian approach to measurement scheme analysis in multistation machining systems

2003 ◽  
Vol 217 (8) ◽  
pp. 1117-1130 ◽  
Author(s):  
D Djurdjanovic ◽  
J Ni
Keyword(s):  
Bayesian Approach ◽  
Machining Process ◽  
Machining Processes ◽  
Machining Errors ◽  
Machining System ◽  
Stream Of Variation ◽  
Linear State ◽  
Dimensional Errors ◽  
Scheme Analysis

Different measurement schemes in multistation machining systems carry different amounts of information about the root causes of dimensional machining errors. The choice of a measurement strategy in a multistation machining system is therefore crucial for subsequent successful identification of the machining error root causes. Recent advances in the linear state-space modelling of dimensional errors in multistation machining processes facilitate a formal and systematic characterization of measurement schemes. In this paper, the stream-of-variation methodology is employed to characterize various measurement schemes quantitatively in multistation machining systems using the Bayesian approach in statistics. Application of these methods is demonstrated in the characterization of measurement schemes in the machining process used for machining of an automotive cylinder head.

Applications of Transmission Electron Microscopy in the Characterization of Metal Machinability

1968 ◽  
Vol 26 ◽  
pp. 442-443 ◽  
Author(s):  
L.E. Murr ◽  
A.B. Draper
Keyword(s):  
Electron Microscopy ◽  
State Physics ◽  
Test Material ◽  
Milling Machine ◽  
Rotary Table ◽  
Solid State Physics ◽  
Materials Properties ◽  
Transmission Electron ◽  
Selection Of

The industrial characterization of the machinability of metals and alloys has always been a very arbitrarily defined property, subject to the selection of various reference or test materials; and the adoption of rather naive and misleading interpretations and standards. However, it seems reasonable to assume that with the present state of knowledge of materials properties, and the current theories of solid state physics, more basic guidelines for machinability characterization might be established on the basis of the residual machined microstructures. This approach was originally pursued by Draper; and our presentation here will simply reflect an exposition and extension of this research.The technique consists initially in the production of machined chips of a desired test material on a horizontal milling machine with the workpiece (specimen) mounted on a rotary table vice. A single cut of a specified depth is taken from the workpiece (0.25 in. wide) each at a new tool location.

Feature selection of the armature winding broken coils in synchronous motor using genetic algorithm and mahalanobis distance

2012 ◽  
Vol 57 (3) ◽  
pp. 829-835 ◽  
Author(s):  
Z. Głowacz ◽  
J. Kozik
Keyword(s):  
Genetic Algorithm ◽  
Feature Selection ◽  
Mahalanobis Distance ◽  
Distance Measure ◽  
Synchronous Motor ◽  
Medical Diagnostics ◽  
Motor Current ◽  
Feature Spaces ◽  
Multidimensional Feature Spaces ◽  
Selection Of

The paper describes a procedure for automatic selection of symptoms accompanying the break in the synchronous motor armature winding coils. This procedure, called the feature selection, leads to choosing from a full set of features describing the problem, such a subset that would allow the best distinguishing between healthy and damaged states. As the features the spectra components amplitudes of the motor current signals were used. The full spectra of current signals are considered as the multidimensional feature spaces and their subspaces are tested. Particular subspaces are chosen with the aid of genetic algorithm and their goodness is tested using Mahalanobis distance measure. The algorithm searches for such a subspaces for which this distance is the greatest. The algorithm is very efficient and, as it was confirmed by research, leads to good results. The proposed technique is successfully applied in many other fields of science and technology, including medical diagnostics.

Nanoprobe Characterization of Soft SRAM bit Fails in Advanced Technologies

2019 ◽  
Author(s):  
Satish Kodali ◽  
Chen Zhe ◽  
Chong Khiam Oh
Keyword(s):  
Yield Loss ◽  
Performance Metrics ◽  
Root Cause ◽  
Advanced Technologies ◽  
Capacitance Voltage ◽  
Defect Localization ◽  
Cv Measurements ◽  
Lightly Doped Drain ◽  
Dc Characterization

Abstract Nanoprobing is one of the key characterization techniques for soft defect localization in SRAM. DC transistor performance metrics could be used to identify the root cause of the fail mode. One such case report where nanoprobing was applied to a wafer impacted by significant SRAM yield loss is presented in this paper where standard FIB cross-section on hard fail sites and top down delayered inspection did not reveal any obvious defects. The authors performed nanoprobing DC characterization measurements followed by capacitance-voltage (CV) measurements. Two probe CV measurement was then performed between the gate and drain of the device with source and bulk floating. The authors identified valuable process marginality at the gate to lightly doped drain overlap region. Physical characterization on an inline split wafer identified residual deposits on the BL contacts potentially blocking the implant. Enhanced cleans for resist removal was implemented as a fix for the fail mode.

Case Study and Fault Modeling for Wrong Redundancy Evaluation on DRAM Devices

2007 ◽  
Author(s):  
Martin Versen ◽  
Dorina Diaconescu ◽  
Jerome Touzel
Keyword(s):  
Failure Mode ◽  
Failure Modes ◽  
Fault Modeling ◽  
Mode Analysis ◽  
Root Cause ◽  
Failure Mode Analysis

Abstract The characterization of failure modes of DRAM is often straight forward if array related hard failures with specific addresses for localization are concerned. The paper presents a case study of a bitline oriented failure mode connected to a redundancy evaluation in the DRAM periphery. The failure mode analysis and fault modeling focus both on the root-cause and on the test aspects of the problem.

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