Time-based machine-process grouping

The quality of manufacturing design has fundamental impacts on the production performance. In designing manufacturing cells, people often apply group technology to group the parts into the different machine families and/or parts families based on product or process features. This often relies on individual´s experience and qualitative logical analysis. The results can be subjective and arbitrary. However, major impacts by machine/process grouping are often on the overall cycle time and throughput due to set-up/change-over losses. This research proposed a time-based machine/process grouping method based on similarity concept and set-up/change-over times. A dendrogram is used to group the processes and machines. An Excel-based grouping program is established to automate the objective quantitative process ready for engineers to use. Using data from a real semiconductor fabrication plant, simulation models were used to test the performance of the proposed grouping technique. First-in-first-out and critical ratio dispatching rules were experimented. The results show that the proposed grouping technique has far better performance than the existing grouping and two other comparative methods in throughput, average cycle time, average WIP (work in process), delivery rate and move.