Comparison of optimal calculation of inventories

The purpose of this study is to determine and find out the amount of optimal inventories with EOQ approach method (Economic Order Quantity), EOI (Economid Order Interval), Min-Max (Minimum-Maximum Inventory), and other calculations according to company policy. The object of this research is Rajalu Ltd., a private company that engaged in melting aluminum and is located in Gresik city, Surabaya, Indonesia. The raw material used is aluminum scrap, which is obtained from the purchase of foreign imports and local purchases in the country. The research method used was a descriptive study where data collection is collected, analyzed, processed and then interpreted so it can find out what the problem is and can give you an idea of the problem solving while the data types are quantitative and qualitative. The data collected for this research are the data of the needs of raw material (Kg) and supplies (Kg) from 2007 to 2012. The four method calculations, three method of calculations according to EOQ, EOI and Min-Max and the calculations according to company policy, apparently the result is obtained from comparison between 6 item, 2 item is ordering frequency (38 times) and inventory costs (IDR 99.891.213) is the most minimal calculations of EOI method while the other four items is relatively comparable.