Simulation experiment was employed to investigate the schemes for coordinating JIT practices to promote performance upgrade in a job shop environment with the pull system.
The four related essential JIT practices (job shop JIT practices) investigated include: cellular manufacturing (CM), operations overlapping (OPOVR), reduction of set‐up/processing time variability (variability reduction) and set‐up time reduction (STR).
Experiment findings suggest that coordination of CM and STR should be given the priority. While the extent of STR effected by CM substantially influences the efficacy of adopting a cellular layout, the choice of adopting a functional layout (FL) is more likely to be affected by the STR resulted from improvement of set‐up operations (set‐up improvement). Variability reduction tends to be more effective for a cellular layout. For a cellular layout without OPOVR, the effectiveness of reducing set‐up time variability is prominent and almost impervious to the extent of set‐up improvement. For a FL, the effect of variability reduction is minor; reduction of set‐up time variability is effective in this case only for a set‐up to processing time ratio of 20 or larger. The findings of this study do not justify the implementation of OPOVR in the shop environment, even with the support of the other three job shop JIT practices.
This study is notable in integrating STR into the job shop JIT practices to achieve overall performance improvement. In addition, the resulting strategies for variability reduction are essential for adapting the pull system to job shop manufacturing. Therefore, the findings of this study form systematic guidelines enabling exercise of the job shop JIT practices coherently to promote reform of job shop manufacturing.
