探討允許批量分割之等效平行機排程程序-以某成衣廠為例

Identical Parallel Machine Scheduling Procedures With Lot-Splitting－A Case Study of a Ready-to-Wear Manufacturer

馮正廷(Cheng-Ting Feng)

指導教授 ： 張玉鈍

國立臺北科技大學/管理學院/工業工程與管理研究所/碩士(2009年)

https://doi.org/10.6841/NTUT.2009.00199

摘要

平行機台排程使用未允許批量分割之基本派工法則進行排程時，當工單較多、工期與交期變異大，便易造成機台產能的閒置或工單的延誤。本研究以某成衣製造廠為例，運用模擬系統建構等效平行機台生產模型，並提出結合兩種批量分割情境的工單導向啟發式排程程序，稱之為動態批量分割時機程序，決定每張工單之批量分割時機，以降低工單延遲時間與機台閒置時間。研究中以平均機台閒置時間、平均機台設置時間與平均工單延遲時間三項績效作為衡量標準，與在單項績效分別表現較佳的最短處理時間(SPT)、最小設置時間(MST)、最早交期時間(EDD)三種基本派工法則，進行比較，並按個案公司之三項績效權重值計算整體績效比較之。實驗結果顯示，以本研究提出之動態批量分割時機程序，將210張工單排於30台等效平行機台時，平均機台設置時間雖增加10天，但平均機台閒置時間由114天降至30天左右，且幾乎不會延誤工單交期。本研究並設計不同工單組合情境實驗之；結果顯示，雖然使用動態批量分割時機程序時，機台設置時間雖有增多，但在整體績效表現上，比起單純結合批量分割的三種基本派工法則，皆有明顯的改善。

關鍵字

等效平行機 ； 物件導向排程 ； 生產排程 ； 批量分割

並列摘要

When the number of work orders, variances of processing times and due date increase, and basic dispatching rules without lot-splitting are used to schedule work orders on parallel machines, idling of machines and delay of work orders often occur. In this study, we construct simulation models for identical parallel machine scheduling with proposed job-oriented dispatching heuristics with two different lot-splitting processes, which we name it as dynamic lot-splitting timing procedure. The proposed procedures focus on whether to split a work order and how to split when a order is about to be scheduled. The procedure is applied to the case of a ready-to-wear manufacturer. We use machine setup times, machine idle times and order delay times as measurements to evaluate the effectiveness of the heuristic.
SPT(shortest process time), MST(minimum setup time) and EDD (early due date rules, which are known for their nature to have good perfomance on those three measures correspondently, were utilized for comparison. When the proposed heuristic is applied to an example of scheduling 210 work orders on 30 identical parallel machines, the result shows that total machine idle time decreases from 114 days to 30 days and total order delay times decreases from 3 days to zero, while total machine setup times increases 10 days. We also design different experimantal scenarios to evaluate the effectiveness of the dynamic lot-splitting timing procedure. Although the machine setup times may increase, the proposed procedure does generate better schedules than the three basic dispatching rules and their variant respect to the objectives of reducing machine idle times and order delay times.

並列關鍵字

Identical parallel machine ； Job oriented scheduling ； Production scheduling ； Lot-splitting

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