Abstracts Engineering

Facility Layout with Flow Directionality Considerations Imposed by Multiple Operation Sequences

by Krishna Udai Tennati

Flow between departments is a criterion often used to evaluate the overall flow of layouts. Planning for effective flow involves combining various flow patterns with adequate aisles to obtain a progressive movement of materials, information, or people between departments. Effective flow within a department involves progressive movement of materials, information or people between workstations. Effective flow within a workstation addresses the progressive movement of materials, information and people through a workstation. In order to get a resultant effective flow in a facility the following three principles have to be observed: maximize directed flow paths, minimize flow, and minimize the costs of flow. The principle of minimizing flow calls for eliminating intermediate flows between source and destination and combining flows wherever possible. The principle of minimizing the costs calls for mechanization of material handling and minimizing material handling distances in the layout.The primary goal of this research was to maximize directed flow paths and this was done by capturing the directionality embedded in the operation sequences of the parts produced in the facility. This goal was achieved by two different methods: The first method determined how to design a practical layout as a combination of the different traditional layouts. Due to the variety of products that the facility produces, none of the three traditional layouts  – Functional, Flowline and Cellular  – individually provides a good layout design that fits the material flow network. To address this problem, we proposed a method to model the layout as a network of “layout modules”. Each module has a unique material flow pattern, which, in some cases, is identical to that of one of the traditional layouts. The second method incorporated directionality into the existing design skeletons by using a Maximum Spanning Arborescence, to determine the adjacencies in a block layout. The concepts and methods developed in this thesis extend the state-of-the-art in the theory and practice of facility layouts as follows:- It views the “department” in a facility can be a combination of multiple processes, instead of a single process.- It presents a logical approach to machine duplication of the same type at multiple locations in a facility based on its joint occurrence with different combinations of machines in more than one group of similar routings.- It demonstrates that more than one type of layout can be used to arrange different machines and resources in a facility.- It establishes the use of operation sequences to design a Cellular layout as a generic method for the custom design of any facility layout.- It proposes the use of a design skeleton with directionality derived from the operation sequences.- It suggests methods to improve the adjacency structure of the design skeleton using a special classification of the edges.