A new representation of product routings for design of layouts for jobshops.

摘要

The design of layouts for jobshops that process a high variety of products requires the representation and analysis of a large number of different product routings. Traditionally, the representations of multiple product routings have been segregated into two categories: The From-To Chart, Flow Diagram and Multi-Product Process Chart are used for facility layout; whereas, the Machine-Part Matrix and Cluster Analysis Dendrogram are used for cell formation.; The From-To Chart is the primary form of quantitative input data that is used for facility layout. However, its simple weighted directed graph structure is suitable for the design of a single classic type of layout for a facility—the Functional (or Process) Layout. This is because the From-To Chart aggregates all routings connecting any pair of departments into a single flow between them. This flow aggregation does not influence the design of the Functional Layout since a department does not have to be split and duplicated at multiple locations. But, if it is desired to design a layout that necessitates department splitting (or machine duplication), then the From-To Chart may not be the correct form of input data. This is because its structure is unable to associate a particular family of operation sequences with each copy of a department (or machine) placed at any of several locations.; Our study proposes a new charting tool—Modified Multi-Product Process Chart (MM-PPC)—that combines the capabilities of all the traditional tools aforementioned. The method was inspired by the techniques used in genetics for matching, clustering and alignment of strings and hypergraphs used to design VLSI chip layouts facility. An MMPPCs contains the same basic information as traditional tools—a sample of routings in a facility. The difference is that it enables machine duplication in facility layouts without loss of machine-part association in the material flow network. Extensive discussions on mathematical modeling, algorithm implementation and industrial case studies on hybrid layout design are given in this study.