電腦模擬於流程型工廠之應用-以光罩護膜前端製程為例

The Application of Computer Simulation on Flow Shop Factory － for Frontend Processes of Pellicle

黃雅鈴(Ya-Ling Huang)

指導教授 ： 梁韵嘉

元智大學/工程學院/工業工程與管理學系/碩士(2011年)

摘要

案例公司為國內少數生產光罩護膜的公司之一，由於受到機台治具數量的限制，多種產品型號共用一組治具，且換模時間冗長，生產管理者目前多以治具為依據，再以交期為考量作為生產排程依據，而導致經常發生早交或遲交的狀況。為了解決案例公司此種問題，本研究中，以AutoMod模擬軟體分別建構三種生產模型，並以換模次數及延遲訂單數作為績效衡量的評估準則。
本研究主要分為三個主題進行研究，分別為流程改善、多能工和瓶頸機台，在流程改善研究中，模型一為實際案例公司的生產流程，派工模式包括EDD(Earliest Due Date)、AT-RPT(Arrival Time-total Remaining Processing Time)、SPT(Shortest Processing Time)、MST(Minimum Slack Time)、MDD(Modified Due Date)、CR(Critical Ratio)等六種；模型二則是訂單在進入CNC工作站之前，設定一個檢驗站，根據距交期之遠近(10、20及30天)決定訂單之生產優先順序，而派工模式則同模型一；模型三的生產流程則是將訂單置於同一個等候線(queue)中，派工法則則是分別將交期及治具設定權重，並觀察其換模次數及延遲訂單數。多能工研究則是分別找出利用率最高和最低的作業員進行多能工的指派，並以換模次數及延遲訂單數作為績效衡量的評估準則。瓶頸機台的研究則是觀察流程改善研究和多能工研究中機台和作業員瓶頸狀況並觀察有無瓶頸漂移的狀況。
本研究結果顯示，流程改善研究中，以模型三治具和交期權重比值為(0.9，0.1)、(0.7，0.3)、(0.8，0.2)、(0.6，0.4)、(0.5，0.5)可得到較好的結果。多能工方面較佳的表現則包括：1. 模型三治具和交期權重比為(0.9，0.1)且多能工指派為CNC幫drill，其延遲訂單數及換模次數改善幅度分別為47.45%及17.90%；2. 模型三治具和交期權重比為(0.8，0.2)且多能工指派為CNC幫drill，engrave幫edge，其延遲訂單數及換模次數改善幅度分別為42.86%及25.33%；3. 模型二距交期10天AT-RPT派工模式中，多能工指派為CNC幫drill，engrave幫edge，其延遲訂單數及換模次數改善幅度分別為53.57%及1.31%。而瓶頸問題方面，瓶頸機台則是發生在edge站和drill站，本研究不論在流程改善或多能工中並沒有發現瓶頸漂移的情況，但在WIP、機台和人員利用率上，多能工的實施則有較明顯的改善。

關鍵字

流程式生產 ； 系統模擬 ； 排程 ； 多能工

並列摘要

The case company is one of the domestic companies that produce pellicle. In the front-end process of the pellicle, because the number of fixtures is limited, lots of products share the same type of fixture, and the time of changing fixtures is tedious, production planners usually arrange the processing sequence of orders based on the change of fixtures, and then the due date of the orders. However, the current dispatching rule often leads to earliness or lateness conditions which may cause the extra inventory or lateness penalty respectively. To remedy this problem, this study employs AutoMod simulation software to build three scenarios and evaluates their performance based on the number of fixture changes and the number of tardy orders.
The three main themes of this research consist of production flow improvement, multifunctional labors, and bottleneck machines. In the production flow improvement research, three models are considered: the first one represents the current status of the company's production process. Six different dispatching rules are investigated here including EDD (Earliest Due Date), AT-RPT (Arrival Time-total Remaining Processing Time), SPT (Shortest Processing Time), MST (Minimum Slack Time), MDD (Modified Due Date), and CR (Critical Ratio).; the second model sets up a checkpoint to determine the priority of orders based on the urgency of the due date; the last model sends all orders in the same queue, but determines the processing sequence based on the weighted criterion of both due date and the fixture change. The second main theme of this study analyzes the utilization of the current production line, and then assigns the staffs in the low utilization workstation extra task – so called multi-functional labor while in the last theme the bottleneck drift of the last two themes is observed and analyzed.
The simulation results show that in the flow improvement study, model III – the weighted criterion provides better results in both number of fixture change and the number of tardy orders. In the theme of multi-functional labors, three major improvements are identified from the Pareto front and the percentage improvement on the number of fixture changes is between 42.86% and 53.57% while the improvement on the number of tardy orders may fall between 1.31% and 25.33%. As for the last theme, no bottleneck drifting is identified, but the WIP and the utilization of machines and staffs are improved through the models above and particularly in the multi-functional labor.

並列關鍵字

Flow Shop ； System Simulation ； Scheduling ； Multi-Functional Labor

參考文獻

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