Abstract
The paper tries to investigate and compare three production control policies, HP production control policy, zero production control policy and (z, Z) production control policy, in flow-shop manufacturing system. A HP production control policy is characterized by a number z*, which is regarded as the optimal amount of inventory to be kept. If current inventory level exceeds z*, the system be set to produce nothing；if less than z*, the system should be set to produce at the maximum rate；if the inventory level exactly equals z*, the system should be set to produce exactly enough to meet demand and thereby keep the inventory level at z*. A zero production control policy is also characterized by a number z* which is regarded equal zero. A (z, Z) production control policy is characterized by two control limits z < Z. The machine keeps on producing at its maximal capacity until the inventory level Z is reached. Once this inventory level is reached, we adjust the production rate of the machine to zero until the inventory level z is reached. We find that (z, Z) production control policy is better than zero production control policy in many cases. For example, in case that the capacity far more exceeds the demand, the usual belief is that zero production control policy can lower total cost. However, our simulation experiment results show that (z, Z) production control policy is better than zero production control policy. In case that the demand is close to the capacity, HP production control policy will be better than the other two policies. The simulation to estimate the expected inventory & shortage per unit time and to estimate the (z, Z) values for (z, Z) production control policy is based on that we model the unreliable single machine system in a renewal process. 一、製造系統或生產線的類型…………………………………………………..1 二、製造系統或生產線的生產控制策略問題…………………………………..1 三、本論文研究之製造系統及問題……………………………………………..2 四、本文章節架構………………………………………………………………..2 第貳章 生產控制策略文獻回顧及本文研究目的、方法及步驟…………………3 一、生產控制策略文獻回顧……………………………………………………..3 (一) HP production control policy……………………………………………..3 (二) 零庫存式之生產控制策略…………………………………………… ..6 (三) (z, Z) production control policy…………………………………………..8 二、研究目的、研究方法及步驟………………………………………………..9 第參章 三種生產控制策略在單機台系統之數學模型…………………………..11 一、系統共同環境…………………………………..…………………………..11 二、生產控制策略之比較模型……………………..…………………………..11 (一) HP production control policy模型……………………………………...13 (二) 零庫存式之生產控制策略模型……...…….………………………….14 (三) (z, Z) production control policy……...…….……...…………………….15 第肆章 單機台 (z, Z) 生產控制策略…...…….……...…………………..…...….17 一、(z, Z) 生產控制策略對存貨水準影響之觀察……...……………..…...….17 二、估算 (z, Z) 值之模擬方法……...…………………………..……..…...….19 (一) Check Method(對每組數據，檢驗 時間內的當機次數)…………20 (二) 計算每組數據之 …...……………………..…………..……..…...….23 (三) 計算每組數據之存貨數與缺貨數…………..………..…….....…...….26 三、實例演練……...……………………………….……………..……..…...….33 四、使用eM-plant 軟體，對此模擬方法之驗證…….……………..……..….35 第伍章 模擬驗證、比較與分析 …….…………..………………………..…..….37 一、HP control policy之 z* 值之驗證……..………………………..……..….37 二、三種生產控制策略之比較……..…………………..………………..…..….40 第陸章 研究貢獻與未來可進行研究之方向……………..……………..…….….43 一、研究貢獻…….…………..………………………..…..…………..…………43 二、未來可進行研究之方向……………………..…..………………………..…43 第柒章 參考文獻…….…………..………………………..…….…………………45 第捌章 附錄………………………………………………………………………..47 附錄一：模擬方法之程式碼……………………………………………………47 附錄二：單機台HP production control policy 程式碼………………………57 附錄三：單機台每天存、缺貨紀錄程式碼……………………………….……58 附錄四：(z, Z) 生產控制策略之程式碼……………………….………….……59