DEVELOPMENT OF PART REPLENISHMENT APPROACH TO IMPROVE PRODUCTION EFFICIENCY IN LOW VOLUME AUTOMOTIVE ASSEMBLY COMPANY

Abstract

The part replenishment system (PRS) has long been studied in the manufacturing field where the study has been mostly carried out in internal replenishment (warehouse and inventory), and the external replenishment (distribution and logistics). However, it was found that there was a lack of PRS work in the in-house replenishment (production floor) consisting of material management between warehouse and production floor. Since the material replenishment activities are usually carried-out by warehouse personnel, the material management issues might be overlooked during preparation of production system. Most studies carried out on material replenishment in the production floor were based on trial and error, which only solved the issue if occurred during production process. Consequently, the difficulties arise in deciding which direction or guide should be taken for part replenishment improvements. Thus, in this thesis, systematic approach of PRS for strengthening the material management between warehouse and production floor was developed to improve the efficiency and effectiveness of the production floor. The developed approach consisted of three main phases, which were manufacturing system identification, Part Replenishment (PR) strategies and techniques, and the verification and validation of the approach. Three techniques of the PRS were identified based on the chronology of the manufacturing perspective in the pull and push system, namely self-service, ad­hoc and dedicated. The PR strategies were then developed with an interaction of different number of trolleys and different number of shelves or modes, where the trolley consisted of single and dual, while maximum number of three shelves was employed. Each strategy or mode based on combination number of trolley and shelves was examined in terms of waiting time by using queuing analysis theory and analyzed by using WITNESS simulation software. The result showed the dual system with three shelves (Mode 5) was identified as the optimum strategy that increased the production output and provided a smoothness production flow which consequently optimized the production lead time and avoiding part shortage, part missing and part mixing. The developed PRS approach was then verified, validated and implemented in a selected case study industry where the dedicated dual system with three shelves (Mode 5) had drastically increased the target output from 5 units to 16 units per day. In overall, the developed PRS approach has ensured that the materials are replaced at the right time, with the right quantity and at the right place by eliminating the waste of waiting time and avoiding production idling.