Combined parameter and tolerance design optimization with quality and cost

Jeang, Angus

doi:10.1080/00207540010006717

Cited by 62 publications

(26 citation statements)

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“…Jeang [8] applies response surface methodology to minimise the total cost, which consists of tolerance cost and quality loss. Jeang [9] further develops a model for simultaneous optimisation of parameter and tolerance design which covers the cycle from product to process design.…”

Section: Literature Reviewmentioning

confidence: 99%

A general model for process-setting with an asymmetrical linear loss function

2005

Int J Adv Manuf Technol

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In many industries, unbalanced tolerance design is a common occurrence. It occurs when the deviation of a quality characteristic in one direction is more harmful than the deviation in the opposite direction. The failure mode in the two directions is usually different. Taguchi redefines quality using Gauss's quadratic function as the loss that a product imparts to society from the time the product is shipped. However, using a quadratic loss function when the actual loss function is nonquadratic may yield incorrect input parameter levels. In certain situations, a linear loss function is more appropriate in industrial applications. Furthermore, automatic inspection and measurement technology is widely used by many industries; the nonconforming quality characteristic would be detected automatically. Thus, rather than use a quadratic loss function, we assume a truncated asymmetrical linear loss function to describe unbalanced tolerance design. The purpose of this paper is to find out the optimal setting of the process mean such that the expected quality loss is minimised. The results show that the process mean should be slightly offset from the target value.

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Section: Literature Reviewmentioning

confidence: 99%

A general model for process-setting with an asymmetrical linear loss function

2005

Int J Adv Manuf Technol

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“…Jeang [13] applies response surface methodology to minimise the total cost which consisted of tolerance cost and quality loss. Jeang [14] further develops a model for simultaneous optimisation of parameter and tolerance design which covered the cycle from product to process design.…”

Section: Literature Reviewmentioning

confidence: 99%

Optimal target selection for unbalanced tolerance design

2004

The International Journal of Advanced Manufacturing Technology

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In many manufacturing processes, unbalanced tolerance design is a common occurrence. It occurs when the deviation of a quality characteristic in one direction is more harmful than in the opposite direction. The failure mode in these two directions is usually different. Furthermore, automatic inspection and measurement technology are widely used by the industries. The nonconforming part will be detected automatically. Thus, a truncated asymmetrical quadratic loss function is assumed for the unbalanced tolerance design. Traditionally, the manufacturer would either choose the smaller tolerance as the tolerance for both sides, or would set the process mean at the middle of the tolerances. Both methods fail to minimise the expected quality loss. The purpose of this paper is to find out the optimal manufacturing setting such that the expected quality loss is minimised. The results show that the process mean should be shifted a little from the target value.Notation y quality characteristic l process mean of a quality characteristic r standard deviation of a quality characteristic L(y) quality loss function of a quality characteristic, y T target value of a quality characteristic D one side tolerance of a symmetrical specification A quality loss at the specification limits of a symmetrical quality loss function k coefficient of a symmetrical quality loss function k 1 coefficient of an asymmetrical quality loss function on the left-hand side k 2 coefficient of an asymmetrical quality loss function on the right-hand side R k asymmetrical ratio of the coefficient of the quality loss function, i.e. R k =k 1 /k 2 D 1 tolerance on the left-hand side of an unbalanced tolerance D 2 tolerance on the right-hand side of an unbalanced tolerance A 1 quality loss at the specification limit on the left hand side for an unbalanced tolerance design A 2 quality loss at the specification limit on the right hand side for an unbalanced tolerance design R A quality loss ratio at the specification limits, i.e. R A =A 1 /A 2 L(d, A 1 , A 2 ) expected quality loss as a function of d, A 1 and A 2 d standardised distance of the process mean apart from target value, i.e. d= (lÀT)/r l o optimal process mean that minimises expected quality loss d o optimal standardised distance of the process mean apart from target value, i.e. d o =(l o ÀT)/r USL upper specification limit LSL lower specification limit C p process capability ratio, i.e. C p = (USLÀ LSL)/6r R L quality loss ratio, i.e. R L =EL (0)/EL(d o ) AR A (actual value of R A )/(estimating value of R A ) AR k (actual value of R k )/(estimating value of R k ) d o * standardised distance of the process mean apart from target value computed by the actual values of R k and R A Err_d o error ratio of d o , i.e. Err_d o =(d o * Àd o )/d o

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“…Failure cost appears whenever the quality characteristic of interest falls outside the design specifications. Because various combinations of parameter and tolerance values will lead to widely different quality loss, tolerance cost, and failure cost, it becomes necessary to determine two design values simultaneously so that all costs involved can be truly minimized [12,14]. Hence, the total cost(response value) for this application of RSM should include quality loss, tolerance cost, and failure cost.…”

Section: Experimental Design Via Rsmmentioning

confidence: 99%

“…Conventionally, parameter design is carried out prior to tolerance design due to economic considerations (two-stage strategy). However, for the first type of input variables in product or process design, if the output quality characteristics resulting from parameter and tolerance design can be measured in a common monetary unit, an optimization of parameter and tolerance design may be achieved in one stage (one-stage strategy) [2,3,12,14,17].…”

Section: Introductionmentioning

confidence: 99%

Simultaneous Parameter and Tolerance Design for an Electronic Circuit Via Computer Simulation and Statistical Optimization

Jeang

2003

The International Journal of Advanced Manufacturing Technology

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Conventionally, parameter design is carried out prior to tolerance design for economic reasons. However, a combined parameter and tolerance design may be completed in one stage for further cost reduction and quality improvement. In this study, a simultaneous optimization of component parameter and component tolerance for an electronic circuit design is realized via computer simulation and Response Surface Methodology (RSM). The approach first generates a set of outputs (experimental data) through computer simulation based on various combinations of parameter and tolerance levels as inputs. Then these outputs are converted into a total cost as a response value before applying RSM for statistical analysis and optimization. The response value(total cost) includes quality loss, tolerance cost, and failure cost, which reflect the combined effect of the assigned parameter and tolerance values being assigned. In this study, computer simulation can be carried out by two methods. The first method uses Monte Carlo Simulation to generate the outputs with the condition that the transfer function is known. The second method uses a PSpice simulation program to generate outputs without necessarily knowing the transfer function. The results provide designers with the optimal component parameter and tolerance values, and the critical components, and the response function -all of which are very important during the early design activities as they enable designers to have a repeated application, accurate feedback and appropriate suggestions, particularly under uncertain design conditions.

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Combined parameter and tolerance design optimization with quality and cost

Cited by 62 publications

References 0 publications

A general model for process-setting with an asymmetrical linear loss function

A general model for process-setting with an asymmetrical linear loss function

Optimal target selection for unbalanced tolerance design

Simultaneous Parameter and Tolerance Design for an Electronic Circuit Via Computer Simulation and Statistical Optimization

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