Embedding JIT in MRP: The case of job shops

Abstract

The philosophy and principles needed to institute JIT in any system, including a job shop, are described. A simulation model is developed using a benchmark job shop to study using a pull system in a job shop having variations in processing times, load levels, and machine breakdowns. It is inferred from simulation that JIT can be implemented if certain conditions are met. Processing time variations did not pose a serious impediment, but load levels and machine breakdowns were critical factors. With uneven loading, the resulting capacity bottlenecks make the pull system look like a push system. This can be avoided by processing a uniform mix of jobs to not violate workstation capacity limitations. If machine breakdowns are unavoidable, maintenance of buffer capacity is essential. © 1994.