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

• Main Authors: Hartini, Sri, Prastawa, Heru, Jayaningtyas, Sitoarum
• Format: Article in Journal/Newspaper
• Language: English
• Published: Departemen Teknik Industri, Fakultas Teknik, Universitas Diponegoro 2012
• Subjects: sami
• Online Access: https://ejournal.undip.ac.id/index.php/jgti/article/view/2045; https://doi.org/10.12777/jati.5.1.55-66

Sistem pemesanan produk dari customer mengijinkan adanya revisi demand dengan fluktuasiyang telah disepakati. Sistem persediaan PT. SAMI selama ini belum dapat mengakomodasi perubahandemand tersebut. Sering terjadi shortage dan overstock yang berpengaruh pada besarnya biaya totalpersediaan yang harus dikeluarkan. Minimasi biaya total persediaan dapat dicapai dengan peramalandemand aktual dan sistem persediaan yang tepat. Saat ini PT. SAMI tidak melakukan peramalan untukmemperoleh perkiraan demand aktual. Perkiraan kebutuhan produksi dan sistem pemesanan materialnyahanya berdasarkan pada perkiraan demand dari customer tanpa pertimbangan apapun denganmenganggap bahwa fluktuasi perkiraan demand dari customer dalam batas yang telah disepakati. Melaluiidentifikasi pola data masa lalu, diusulkan 5 metode peramalan dan metode Winter EksponentialSmoothing (WES) mempunyai tingkat error paling kecil. Selanjutnya metode WES yang terpilih. Selainitu, diusulkan 3 alternatif dalam sistem pemesanan, yaitu perbaikan perkiraan demand, sistem order up toleveldan sistem optional replenishment. Ketiganya mampu menurunkan biaya total masing-masing18,81%, 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 fluctuationwhich has been agreed before. The inventory system that now day PT. SAMI run couldn’t accommodatethose demand change. There’s often happen shortage & over stock which impact on the total inventorycost that PT. SAMI have to spend. Minimalisation of total inventory cost could be achieved with theeffective actual demand forecasting and inventory system. Today PT. SAMI is not conducts forecasting toget the actual demand forecast. The production requirement forecast and material order system is basedonly on demand forecast from supplier without any consideration and PT SAMI just assume that demandforecast fluctuation from customer is still within range of agreement that have been approved. Throughpast data pattern identification, we tried 5 method and we can get Winter Exponential Smoothingforecasting 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, upto-level order system and optional replenishment system. Three of them could cut the total cost down until18,81%, 22,55%, 23,58%.Keyword: Total inventory cost, forecasting, up to-level order, optional replenishment.