USULAN PERBAIKAN SISTEM PERSEDIAAN UNTUK MINIMASI BIAYA TOTAL PERSEDIAAN PADA PT. SEMARANG AUTOCOMP MANUFACTURING INDONESIA

• Main Authors: Sri Hartini, Heru Prastawa, Sitoarum Jayaningtyas
• Format: Article
• Language: Indonesian
• Published: Diponegoro University 2012-02-01
• Series: J@ti Undip: Jurnal Teknik Industri
• Online Access: https://ejournal.undip.ac.id/index.php/jgti/article/view/2045
• ISSN: 1907-1434; 2502-1516

Sistem pemesanan produk dari customer mengijinkan adanya revisi demand dengan fluktuasi yang telah disepakati. Sistem persediaan PT. SAMI selama ini belum dapat mengakomodasi perubahan demand tersebut. Sering terjadi shortage dan overstock yang berpengaruh pada besarnya biaya total persediaan yang harus dikeluarkan. Minimasi biaya total persediaan dapat dicapai dengan peramalan demand aktual dan sistem persediaan yang tepat. Saat ini PT. SAMI tidak melakukan peramalan untuk memperoleh perkiraan demand aktual. Perkiraan kebutuhan produksi dan sistem pemesanan materialnya hanya berdasarkan pada perkiraan demand dari customer tanpa pertimbangan apapun dengan menganggap bahwa fluktuasi perkiraan demand dari customer dalam batas yang telah disepakati. Melalui identifikasi pola data masa lalu, diusulkan 5 metode peramalan dan metode Winter Eksponential Smoothing (WES) mempunyai tingkat error paling kecil. Selanjutnya metode WES yang terpilih. Selain itu, diusulkan 3 alternatif dalam sistem pemesanan, yaitu perbaikan perkiraan demand, sistem order up tolevel dan sistem optional replenishment. Ketiganya mampu menurunkan biaya total masing-masing 18,81%, 22,55%, 23,58%. Kata kunci: biaya total persediaan, peramalan, order up to-level, optional replenishment   The product ordering system from customer is allowing for demand revision with the fluctuation which has been agreed before. The inventory system that now day PT. SAMI run couldn’t accommodate those demand change. There’s often happen shortage & over stock which impact on the total inventory cost that PT. SAMI have to spend. Minimalisation of total inventory cost could be achieved with the effective actual demand forecasting and inventory system. Today PT. SAMI is not conducts forecasting to get the actual demand forecast. The production requirement forecast and material order system is based only on demand forecast from supplier without any consideration and PT SAMI just assume that demand forecast fluctuation from customer is still within range of agreement that have been approved. Through past data pattern identification, we tried 5 method and we can get Winter Exponential Smoothing forecasting method proposal with better degree of accuracy than the current demand forecast method. Besides,this article proposes 3 alternatives in ordering system, such as demand forecast improvement, up to-level order system and optional replenishment system. Three of them could cut the total cost down until 18,81%, 22,55%, 23,58%. Keyword: Total inventory cost, forecasting, up to-level order, optional replenishment.