A simulation study for dynamic scheduling in a hybrid assembly/job shop considering the JIT context

This paper is a report of a simulation study that investigates a dynamic approach to scheduling jobs in a hybrid assembly/job shop, with special application to welding shop operations. Both JIT arrival and JIT delivery are considered. Various dispatching rules with different utilization are tested for the following performance measures; mean flow time, percentage of tardy jobs, mean tardiness, sum of mean tardiness and mean earliness. The results indicate that the SPT rule is the best for the mean flow time. The MSLACK rule, that we suggest in this paper, is the best for mean tardiness, the sum of mean tardiness and mean earliness. However, it is not clear which rule is the best for the percentage of tardy jobs. We also investigate the effect of changing the release time on the performance measure.

Keywords:

• Dynamic Scheduling
• Assembly/job Shop
• Jit Context
• Simulation
• Dispatching Rule