Calculation of Total Cost, Tolerance Based on Taguchiâ€™s, AsymmetricQuality Loss Function Approach

N Alagumurth,R Ramesh,R Sampath Kumar

doi:10.3844/ajeassp.2009.628.634

Abstract

Problem statement: Current world market force the manufacturing sectors to develop high quality product and process design with minimum possible cost. About 80% of problems in production units may be attributed to 20% of design tolerance causes. While design typically represents the smallest actual cost elements in products (around 5%), it leverages the largest cost influence (around 70%). So design engineers continuously stumble upon problem of design for high quality performance with lower cost. Objectives of this study where to: (i) simultaneous selection of design and manufacturing tolerance (ii) minimization of total cost (sum of the manufacturing cost and Taguchi’s asymmetric quality cost) (iii) minimum cost and its machining tolerance. Approach: Rotor key base assembly was considered as case study to optimize the minimization of assembly total cost and machining tolerance. New global nonlinear optimization techniques called pattern search algorithm had been implemented to find optimal tolerance allocation and total cost. Results: In this study minimum cost arrived was 45.15 Cr and its corresponding tolerances for machining process turning, drilling, face milling, face milling and drilling where 0.063, 0.0508, 0.2127, 0.2127, 0.2540 mm respectively at worst case conditions. Conclusion: Results indicated that optimization by integer programming, sequential quadratic programming and exhaustive search, nonlinear programming, genetic algorithm, simulated annealing, fuzzy logic, number set theory and Monte Carlo simulation did not give much least total cost and also predicted that pattern search algorithm was robust method. Second the method, generally termed as concurrent tolerance synthesis was well suited for engineering environment, where high quality products with low total cost were designed and manufactured.

Highlights

Tolerance is defined as the system of specifying the extent of permissible variations In other words the amount of variation permitted for the basic size is called tolerance
If there are three independent variables in the optimization problem, the default for a 2N positive basis consists of the following pattern vectors: With Mesh Adaptive Search Algorithm (MADS), the collections of vectors that form the pattern are randomly selected by the algorithm
Total cost is the summation of manufacturing cost with respective to the tolerance and asymmetric quality loss given in equation 4

Summary

INTRODUCTION

Tolerance is defined as the system of specifying the extent of permissible variations (or) In other words the amount of variation permitted for the basic size is called tolerance. Huang[8] has presented a robust optimization method longer process time, causing higher production in a concurrent tolerance environment. This method can cost[3,4]. Generally termed as concurrent tolerance synthesis is well suited for engineering environment, where high Smaller-the-better is the: quality products with low total cost are designed and manufactured. If there are three independent variables in the optimization problem, the default for a 2N positive basis consists of the following pattern vectors: With Mesh Adaptive Search Algorithm (MADS), the collections of vectors that form the pattern are randomly selected by the algorithm. The results of optimization using pattern search algorithm method are discussed as follows

MATERIALS AND METHODS

RESULTS

DISCUSSION

Findings

CONCLUSION