Simultaneous Manufacturing/Structural Shape Optimization for Minimum Product Cost . (Dept. M. ( Production ) )

Abstract

This paper presents an integrated manufacturing/structural shape optimization method that considers not only structural performance but also machining cost. It explores the tradeoff between mass and machining cost with the application of the end-milling and grinding machining processes to machine and finish a virtual die. The objective function of the integrated optimization problem is the total cost (material & machining). The structural shape is constructed by using B-Splines and hole generation; the design variables are X- and Y-coordinates of the B-Splines control points. The design variables also include the cutting parameters i.e. the cutting speed, the feed rate and the tool diameter. The problem constraints are for both manufacturing and structural shape. The optimization problem will be achieved by interfacing between MATLAB2011aand ANSYS11 programs using Sequential Quadratic Programming (SQP) as a mathematical optimization solver. In this paper, there are three cases of hole generation in the product depending upon the idea of topology optimization. The comparison between the initial total cost and its optimal results for all cases is presented and the influence of the required batch size on the final shape is discussed. It is found that the reduction percentage in the total cost of the virtual die of the last case (i.e. three holes generation) is about 28 % by using SQP algorithm for batch size of 50 pieces after eight iterations and 48% for batch size of 5000 pieces after fourteen iterations. The final optimized shape has also changed as a result of the product batch size demand.