鋼鐵廠-軋鋼製程主生產排程規劃系統之構建

Abstract

鋼鐵廠的生產排程規劃，須先考量鋼胚切割計畫以滿足各訂單對於各 鋼種以及公稱尺寸之規格需求，而為滿足各訂單之交期亦須排定鋼胚在軋 鋼製程中軋延機台的壓延排程，以因應顧客訂單對規格、數量、交期之要 求。為解決鋼鐵廠之排程問題，本文探討鋼鐵廠於流程式生產特性下，考 量鋼胚切割方案、鋼胚在軋延機台壓延時順序相依之整備限制以及各訂單 之交期時間等條件，提出「軋鋼製程主生產排程規劃系統」。 此系統包含兩個模組。首先「軋延機台生產排程規劃模組」，以訂單交 期區間作為規劃週期，先彙整各規劃週期對於各鋼種以及公稱尺寸之規格 需求，以列出所有可行切割方案。接著以最小化未滿足需求為目標，建構 一整數線性規劃模式求解出最佳可行切割方案之組合方式以及軋延機台 的壓延排程。 而「鋼鐵廠內部績效規劃模組」，則依據「軋延機台生產排程規劃模組」 的規劃結果，判斷能否滿足各規劃週期之需求。若可以，則在確保達交之 條件下，以最小化裁切廢料及存貨成本為目標，找出最適的裁切廢料長度 和存貨支數，使廢料重新加工和存貨成本最小；相反的，若無法滿足，則 針對交貨量短缺之週期，規劃出達交所需延遲的時間或無法達交的數量， 以提供顧客決策的資訊。 驗證結果顯示，各規劃週期皆能使用最少的鋼胚數量來滿足訂單需 求，這反應出所挑選的最佳切割方案組合，使裁切廢料重新加工成本和存 貨成本可達最小。整體而言，本文所發展之模式可提供鋼鐵廠生管規劃人 員，排定切割計畫及生產排程來有效因應顧客之需求。 關鍵詞：鋼鐵廠、鋼胚切割計畫、軋延機台、流程式生產、裁切廢料、存 貨、延遲時間

For satisfying product specification, quantity and due date of each order, steel factory need to decide steel ingot cutting plan and make production schedule for hot rolling machine in the hot rolling process. To solve the cutting and scheduling problem, this thesis proposed a master production schedule system regarding to hot rolling process with considerations of sequence dependent setup time and order’s due date. This system includes production scheduling module for hot rolling machine and steel factory performance module. The production scheduling module sets the length of a planning period as the interval between two consecutive due days of orders, and then sum up the demand for each product so as to list all of the feasible cutting schemes. Then the integer programming model is developed to solve the optimal combination of feasible cutting schemes and to plan hot rolling machine production schedule. Based on hot rolling schedule, the steel factory performance module checked whether all of the demands being satisfied. If it is, then the integer programming model is modified for finding the minimal length of wasted material and of ending inventory counts so as to save the cost for reworking the wasted material and for inventory. Contrarily, we cut the planning horizon at the due date that has quantity shortage for delivery, and replan for minimizing the tardy time or the shortage amount so as to communication with consumers. III Experimental studies reveal that simultaneously solving the combination of cutting schemes and the schedule make the demand of each planning period be fulfilled with minimal wasted material and inventory cost. Consequently, the system proposed in this thesis can provide steel factory planner to make cutting plan and production schedule simultaneously to satisfy demands. Keywords: Steel factory, Steel ingot cutting plan, Hot rolling machine, Flow shop, material wasted, Inventory, tardy time