Abstract
Foundry is based on build-to-order manufacturing plan, the purpose of inline WIP control is toward delivery on time. This research proposed a due-date-oriented dispatching rule of furnace station which has Batch Process characteristic. In this circumstance, WIP gather in the queuing area first, and then process together. Since long processing time and non-preemptive are furnace manufacturing features, through Control Strategy to determine suitable time to begins to process in advance. Control Strategy effective to the result of system performance most on Batch Process dispatching decision. According to the literatures on Batch Process dispatching, most studies put focus on reducing waiting time. However, in most foundry companies, to fulfill due-date is at the top of production control. The diversity on the way of goal setting from literatures leads to different dispatching rule design. In this paper, we provide a new furnace dispatching rule which intends to improve delivery performance, being called “Waiting Until Due (WUD)” principle. WUD considers to due-date to decide the time span for postponing furnace operation. Furthermore, WUD combines Look Ahead mechanism which estimates future arrival events according to standard cycle time in advance. As a result, WUD is expected to be satisfied to due-date in primary objective and second is raising batch size. The experiment is built and constructed the simulation model by eM-Plant simulation software, made up of eight furnace machines and seven kinds of products on which all products have different processing time, batch size and individual furnace machines. In experimental design, three kinds of WIP level and three level of slack setup on due, probed into different dispatching rules affected to every performance indices, including CLIP, cycle-time, batch size and utilization. From the result, WUD performed on CLIP and batch size in very effective improvement. Keywords: BTO, Batch Process, Control Strategy, WUD, Look Ahead