Decision support systems for assembly line planning: Modular subsystems for a large-scale production management system.

摘要

In the domain of assembly lines, process sheets are entities that carry assembly process descriptions (work instructions), assembly time estimations, product workspaces and other configuration management and control information. These process sheets get assigned to workstations during the process of assembly line balancing. In this research two tools have been developed to aid in the assembly line planning process. In order to ensure that assembly line workers do not intrude upon each other's workspace, two assembly processes operating on the same product workspace must not be assigned to the same station. Generating and maintaining product workspace information for every process sheet is automated by use of the Product Workspace Identification Tool developed in this research. This tool uses CAD data, custom built analysis software, and web-based databases to define, compute, and store product workspace information.;All assembly work instructions must have time studies. These time studies are used primarily in line balancing. Methods Time Measurement (MTM) is a set of charts that provide standard assembly time estimations based on the parts (and their surrounding space) that are being assembled. In the adapted version of MTM that is used for this research, there are twenty-two MTM tables and several pieces of information are required to arrive at an assembly time study. Using the MTM tables to generate assembly time estimates is cumbersome simply because the number of work instructions for a given product can run into the thousands. The MTM estimate generator presented in this thesis provides decision support to the process sheet author by presenting a reduced set of MTM tables and also by performing filtering within the MTM tables. Testing and validation of this tool showed that it has a mapping accuracy of 75%. These two tools are modular subsystems of a large production management system.