Optimal facility layout and material handling network design

Abstract

The designer of a plant layout is faced with the efficient arrangement of facilities, the planning of material handling locations, and the aisle design. These mutually dependent subproblems are traditionally solved in a sequential process. Designing the material flow paths within the arranged facilities can be difficult and the expected material flow distances between the arranged facilities can be exceeded significantly. Also, when the aisle design is not known, the area between facilities is difficult to estimate and might require costly replanning. The purpose of this study is to investigate the advantage of an integrated planning of these subproblems using a holistic view. We propose two models in this paper. The first is a mixed integer linear programming formulation for concurrently solving small-sized facility layout problems, including the material handling points, and the path design. In a second model aisles are implemented instead of paths, which is a scarcely considered design aspect within the related literature. Several sets of valid inequalities are proposed to shorten the solution time. To compare the solution quality between the proposed integrated approaches and traditional approaches, a comprehensive computational study has been conducted considering several influencing design factors. The results indicate that the integrated planning of the layout and the material handling network design is a large untapped potential for designing superior layout solutions and facilitating the planning process.