Optimizing Raw Material Inventory Control with Continuous and Periodic Review

PT XYZ is a company that operates in the field of plywood processing with various variations that produce products every day. Plywood or plywood is the product with the most demand every month. This company experiences problems, namely ordering raw materials that are uncertain, ordering raw materials because of probabilistic demand with an uncertain period and the quantity of raw materials that does not match the needs used in the production process, so that it often experiences overstock and stockouts. This research aims to control the optimal supply of sengon wood at PT. XYZ by comparing the company's method with the continuous review (Q) back order method and the periodic review (P) back order method to obtain the minimum total inventory costs. Based on calculations using the company method, the total inventory cost is IDR 32,502,564,700 and the minimum total inventory cost is obtained using the continuous review (Q) back order method of IDR IDR 28,829,527,844. The forecasted demand for sengon wood from May 2024 to April 2025 is 42,109 m3. The company made a total order of 944 m3 and a reorder point of 146 m3, so the total inventory cost generated was IDR 36,151,230,302.