KAJIAN KEBIJAKAN PERENCANAAN PRODUKSI DAN INVENTORY DENGAN PENDEKATAN SISTEM DINAMIS DI PT. SEMEN GRESIK PABRIK TUBAN II

Abstract

Nowadays, Manufacturing industries increase every year. One of them that continues to experience demand enhancement, especially demand for cement is PT Semen Gresik. PT Semen Gresik, Tuban Plant II, attempts to meet customers demand with a production and inventory plan that contained in RKAP (Rencana Kerja dan Anggaran Perusahaan – Corporate Work Plan and Budget). However, in reality, RKAP target was not achieved, particularly in 2010. A number of finished products that had been produced were not in accordance with RKAP because of problems that occurred in planning, inventory and operational area. Based on RKAP release/actual production data in 2010, an analysis with dynamic system approach is conducted. This approach enables organization to know factors that influence to manufacturing performance, interrelation between system’s elements, therefore scenarios of policy could be designed. Stella and Vensim are used in this study as software to build the model and simulation. This study started by conducting causal loop, entering data and equations to the Stella software, finally the result of simulation is compared with actual data and validation of model. The findings show that factors influence in manufacturing performance availability of fuel (coals), trass, limestone, clay, and occurrence of downtime and production capacity. Based on sensitivity analysis, the most influential factors are the fuel/coals (delay of 1,5 month impact to coals availability), production capacity (upgrading capacity to 1% could achieve RKAP target), and downtime (maintenance in a minimum one hour will reduce 14,3% downtime). Several policy scenarios are suggested in this research.