Optimization of injection mold based on fuzzy moldability evaluation

The objective of this study is to develop a fuzzy moldability, evaluation approach for the optimization of injection mold. A variable weight profit vector is proposed, which punishes the serious defects and rewards the slight ones. The optimization of injection mold proceeds as follows. First, the defects chosen as criteria for moldability evaluation are expressed as triangular fuzzy numbers according to their seriousness predicted by computer-aided flow analysis and the initial weights of all criteria are assigned utilizing the analytic hierarchy process. Secondly, the varied weight of every criterion is calculated on the basis of the variable weight profit vector and then the fuzzy evaluation matrix is generated. Finally, the moldability indices of various mold schemes are obtained with the technique for order performance by similarity to ideal solution (TOPSIS), which ranks all the alternative mold schemes according to their moldability indices obtained by calculating the distances to both fuzzy serious-defect ideal solution and fuzzy slight-defect ideal solution. The mold scheme with the biggest moldability index is regarded as the best one. A case study on the optimization of mold scheme proves that the proposed approach is valid, feasible, and superior to the others because of its capability in modeling the dynamic fuzzy decision-making logic of human experts. (C) 2008 Elsevier B.V. All rights reserved.