Flexible Integrated Manufacturing Systems: the Concept, its Design, and Optimization Analysis

This paper aims to design and analyze a flexible integrated manufacturing system which combines manufacturing decisions-production planning, process planning, machine loading and production scheduling-and cellular layout under both the production to order and production for stock. The production planning deals with a decision problem which determines the optimal overtime and the production quantities of ordered products at each machine adopted in order to satisfy desired due dates subject to limited resources by considering cellular layout. In the process planning, the process routes by considering alternative machine routing and optimal machining speeds for ordered products are determined. The scheduling problem based on product's slack time for the dynamic cellular manufacturing with different start time deals with a decision problem which determines optimal release time of ordered products. The integrated problem for designing flexible integrated manufacturing systems is formulated as nonlinear mixed integer programming in order to minimize the sum of (1) overhead/machining cost to be needed as exceeding the minimum-cost machining speed, (2) material handling cost for intercell movement, (3) group setup cost and (4) overtime production cost. This is achieved by introducing the marginal cost analysis relating overtime and machining speed on each machine for determining the optimal solutions of each manufacturing decision. An illustration was developted to demonstrate the solution procedure.