การลดจำนวนงานล่าช้าสำหรับโรงงานฉีดขึ้นรูปพลาสติก / วิมลพรรณ คงสมบูรณ์ = Reduction of tardy jobs in the plastic injection molding factory / Wimolphun Kongsomboon
To reduce the number of delayed jobs, the case studies of the factory which it is a plastic injection factory by analyzing for the causes of the problem. We found that the problem of the factory is the raw material is not enough for our production. In the addition, there is not negotiation with the customers, planning and scheduling. As a result, it is delayed. So, the researchers had learned about managing inventory for quantity purchases of raw materials, and we also had developed a computer program used to calculate the number of days in our production, and scheduling of production. This research has led to control inventory with a fixed quantity by purchasing the appropriate size is defined as the quantity to order (EOQ),and the point of purchases (ROP). By using service level (Service Level) at 99% and simulations. The total estimated cost comparison between the original purchase and the fixed purchase quantity system. It can be concluded that these purchases by offering reduced inventory management costs down by about 64.64%, by an amount equal to 1,371,467 baht.For scheduling,production scheduling,it uses a heuristic “A Greedy Algorithms” in order to efficient production scheduling, and it is reduced down after the computer program that we had developed for planning and production scheduling in factories. It can cause the number of delayed production lower (the delayed jobs of production), down from 39.93% to 16.87%.
