Designing a Flexible and Reconfigurable Manufacturing System Considering a Circular Shaped Layout

Abstract

Production demands are constantly changing at a fast pace. The demand for a shorter life cycle and customized products makes it more difficult for factories to adapt. To stay competitive, factories need to be flexible in embracing those continuous changes. Since the second half of the last century, several advanced manufacturing systems have been developed to efficiently produce a variety of products. One of them is the Flexible Manufacturing System (FMS) that has the ability to produce different quantities of different varieties without the need to pause the production line, thus improving process efficiency and lowering production cost. FMS layout includes several arrangements of machines and material handling system and has a significant influence on routing flexibility, machine utilization, factory floor space area, responsiveness to change and productivity. In this research, a new FMS layout, composed of multiple circular loops, is proposed and compared to the traditional open field layout with rectangular loops and ladders. Face Centered Composite Design (FCCD) is applied to investigate the main and interaction effect of product quantity, variety and complexity, and layout design on system performance. The fourth categorical factor considered is the layout shape. Total production cost is used as a system performance metric. To determine this cost, a linear programming (LP) mathematical model is formulated. The model design attributes include cell layout, cell formation, machine capacities, constant and variable machine cost, lot splitting, and alternative process routings. Lingo software is used to solve the formulated optimization model which was validated by comparing it to test cases available in the literature. Response Surface Methodology (RSM) was used for modeling the responses. The main effect plots indicate that increasing the number of locations had the most significant influence on cost, followed successively by product and routing. Results reveal that proposed circular layout is more cost effective than the traditional rectangular open field layout with cost savings reaching 14 % and more when product variety and complexity is increased.