A fuzzy multiobjective approach for minimization of injection molding defects

This paper describes a fuzzy multiobjective optimization approach for deter mining the set-points of the injection molding processing parameters to min imize the defects formed on the molded parts. The severities of the defects are represented by membership functions using the fuzzy set theory. The mi nimization of these membership functions, which is a multiobjective optimiz ation problem, is transformed into a substitute problem. The preference fun ction in the substitute problem is original and is proposed specifically fo r characterizing the quality requirements of the injection molding defects. The formulated optimization problem is solved with design of experiments, in which the process behavior is approximated empirically by a set of quadr atic polynomials that car be easily optimized. Experimental results are pre sented to emphasis the workability of the proposed methodology.