PT. RMC, a company based on make to order which producing ready mixed concrete has not applied a
certain ordering method yet. Giving letter of delivery and job-mix to logistics department close to
production execution time make logistics department cannot determine requirement of material. Beside
that, logistics department works based on work instrument and manual recording so that there are still
found many problems which effect on pile up or shortage.
It needs a method which can provide the decision about material ordering time and quantity so that result
minimum total inventory cost. The method is developed as Decision Support System (DSS). It uses
Material Requirement Planning concept (MRP) with daily phased. Determining economic ordering lot
size uses static Economic Order Quantity (EOQ) with safety stock (SS). DSS determine Q order if
inventory decrease until reach Reorder Point (ROP). With DSS, input and edit data become easier than
before.
In validation, the proposed method is compared with the current method that result the total inventory
cost of proposed method lower than current method. The cost reduction is 10,31 % or Rp.
23.351.790,97439 per month.
Keywords : Inventory, Decision Support System, MRP, EOQ