自動車 工場의 CRS와 PBS 運營에 關한 시뮬레이션 硏究
(A) Simulation Study on the Operation of CRS and PBS in an Automotive Factory
자동차 공장 CRS PBS 시뮬레이션;
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Automotive manufacturing is a complex task with several automated functions. Machined or purchased components are assembled on sub-systems and the sub-assemblies are assembled together over final assembly system. There are usually five major shops in automobile factory, those are press shop, body shop, power train shop, paint shop and trim shop (general assembly shop). The ideal production schedule in an automotive factory is that the production sequence of body shop is the same to the assemble sequence of trim shop. The production system of body shop is batch system and the focus of schedule is to maximize the batch size. However the production system of trim shop is mixed model assembly system and the focus of trim shop is smoothing the various models according to the concept of mixed model assembly. Furthermore in the paint shop they want to group with same colored body as many as possible. Thus the different performance measures of production schedules among the shops make it difficult to optimize production schedule. It is the major reason that most of automotive factories installed three important storages between two shops or between two processes in a shop. Those are WBS (White Body Storage), CRS (Color Rescheduling Storage) and PBS (Painted Body Storage). WBS locates between the body shop and the paint shop, and CRS locates between the primary coating process and the top coating process. On the other hand PBS locates between the painting shop and trim shop. In the thesis two storages, CRS and PBS, are considered for improving the performance of the factory. In chapter 2 we introduce the approach for evaluating the validity of implementing CRS. Configuration of paint shop is explained and performances of CRS are defined. Storage and retrieval algorithms are suggested for the operation of CRS and simulation models are developed using PROMODEL. As a result the grouping ratio of top coating booth is increased to 5.61 form 1.67 by implementation of CRS. We also investigate the effects of the distribution of color and dedicated lane on the grouping ratio. In chapter 3 we develop the storage and retrieval algorithms those are used in PBS for improving the smoothing measures in the trim shop. Configuration of PBS is explained and the performance measures of PBS are defined. Simulation models are developed using QUEST for 3D simulation. As a result the percentage of violation of spacing option decreases about 44% when we compare it to the historical data. We also investigate the effects of the dedicated lane, the maximum storage time allowed in PBS and the maximum waiting time on the first column in each lane on the performance measures.