การวางแผนความต้องการวัสดุและการกำหนดจุดสั่งซื้อใหม่สำหรับผลิตภัณฑ์คอนเนคเตอร์

Abstract

This research was the study to determine the appropriated inventory management policy for connector product materials by material requirements planning with determining the lot size of the order quantity and reorder point. Based on historical data, the case study company hold relatively high inventory values and inventory turnover rates, and there was no standardized method for material requirements planning. It was expected that this study would be the solution to reduce the total cost and improve inventory value and inventory turnover rate. The study focused on connector products group A materials which were sales value 80% of the total connector product. The simulation of material requirements planning in conjunction with safety stock level applied to materials of connector product group A. There were 4 different methods: Economic Order Quantity or Economic Production Quantity, Period Order Quantity, Silver-Meal, and Least Unit Cost. And material requirement planning with reorder point applied to materials of connector product groups B and C.

The results of the research showed that there were 2 materials of connector product group A suited for Static lot sizing methods such as Economic Order Quantity method or Economic Production Quantity method, which could reduce total costs by 18.98% compared with the original method. The other 73 materials were suitable for Dynamic lot sizing methods, there were 35 materials for Silver Meal, 17 materials for Least Unit Cost, 12 materials for Period order quantity, and 9 materials for any methods. These methods can reduce total costs by 7.60% - 11.14% compared with the original method. If select the planning method from the lowest cost method, it resulted in a total cost reduction of 37,652,567 baht or 12.84% compared with the original method. In addition, it also resulted in the total inventory value at the end of the period decreasing from the original 4,583,708 baht or 4.91%, and the inventory turnover rate improved 2 days. However, in real operations, the researcher suggested that the selection of the Silver-Meal method would be good for the operator, it was not too confusing to many methods and mistakes. Silver-Meal was the best total cost after the lowest cost method which could reduce the total cost by 11.14% compared with the original method. For materials of connector product groups, B and C applied to reorder point with material requirements planning to make the standardized planning method and reduce the risk of missing materials due to unsystematic planning.