Production scheduling in a process and assembly job shop

In this paper, the problem of scheduling jobs with processing and assembly requirements in a job shop is addressed. Each job has a product structure o f components and subassemblies that mate together to build up the end produ ct. Each component or subassembly may also require additional processing be fore it can be assembled to its parent part. This paper models the problem using a mathematical programming approach under two production strategies. In one strategy, batches of identical items required by different end produ cts are aggregated together for production to take advantage of setup time reduction. In another strategy, no such aggregation is undertaken. A heuris tic algorithm was developed to address the problem. To test model behaviour , some test problems were run for system analysis. Results From the test pr oblems indicate that Latch aggregation inhibits job flow when setup times a re small and therefore worsens system performance. However, when the setup rimes are moderate to large relative to Latch processing times, there is no performance dominance between the two strategics. The performance measure used in each case is production completion time. Results obtained also indi cate that the heuristic algorithm is effective in solving the models based on solution quality and computational time requirement.