完成品於固定期間交貨情況下SMT生產線之績效評估

Performance Evaluation of SMT Production Lines with Fixed-Interval Deliveries of Finished Items

在許多生產系統，JIT 製造技術的導入是著眼於降低製造成本與提升系統之生產力。本研究探討一網路通訊設備製造商之SMT 生產線，該製造商是屬於“存貨生產(MTS)” 的生產模式，亦即製造商組裝出完成品，然後放入完成品庫存中，最後再根據各客戶之要求在固定期間將完成品運送到客戶處，亦即客戶皆是在JIT 環境下運作。本研究之主要目的是提出一個以模擬為基礎之研究架構，以探討各實驗變數(包括：每週期交貨次數、完成品價格係數、物料前置時間之變異等) 對SMT 生產線之影響程度，本研究所採用的績效指標包括總利潤、服務水準、延遲時間量、與完成品存貨水準。本研究並以一個實際的SMT 生產線為例子，以示範所提出的研究架構。範例之分析結果顯示，若以總利潤為主要的績效指標，每週期交貨次數之表現因其他變數之水準而定；若以服務水準或延遲時間量為主要的績效指標，以低頻率/大批量交貨方式表現較佳；若以完成品存貨水準為主要的績效指標，以高頻率/小批量交貨方式表現較佳。In many production systems, JIT manufacturing technology is implemented both to reduce the manufacturing costs and increase the productivity of the system. This study investigates the performance of the SMT production line in a manufacturer of networking and communication products. The manufacturer is operated in the make to stock (MTS) environment, i.e., it has finished items inventory. The finished items are delivered to customers frequently at a fixed interval by the manufacturer. The customers are all operated in the JIT environment. This study proposes a simulation-based research structure to evaluate the impact of experimental variables (including the number of deliveries per cycle (NDC), finished product price multiplier, lead time variability of materials, etc.) on the SMT production line. The performance indexes used in the study include total profit, service level, tardiness, and inventory level of finished items. Finally, a real SMT production line is used to demonstrate the research structure. Based on the results of the example, the performance of NDC depends on the levels of other variables with respect to the measure of total profit. The NDC with low frequency and large batch size performs better with respect to the measure of service level or tardiness. The NDC with high frequency and small batch size performs better with respect to the measure of inventory level of finished items.