家登精密業務主管沈恩年面臨晶美公司月採購量約4萬套的2吋晶舟盒產品，希望售價要比現有市場價格低40%，新價格為每套35元。然而家登內部估算成本一套是82元，如果承接此4萬套訂單，每月則虧損金額約188萬元，如果不接此訂單，工廠當時的產能利用率太低的問題無法解決，沈協理面臨決策兩難的困境。最後，沈協理基於攤平工廠費用的想法接下此訂單，意想不到市場最低價竟引爆其他客戶紛紛向家登採購此產品，訂單量突然暴增。後續李宗裕廠長利用塑膠模具最佳化設計的能力，將射出成型製造成本的關鍵變數進行計算找出最佳參數，找出原本由一模一穴生產毛利率 -132.8%是虧損的狀態，而最佳化設計後轉變為高毛利30.71%。 本文說明塑膠射出成型產品的生產組成要素，如需配置的作業人力、機台噸位與折舊攤提、模具大小與穴數組成對於模具成本的影響。其中，需求量大的產品可經由最佳化設計來大幅降低單位成本。個案提供的情境能讓學生了解工廠作業現況，並讓學生動手計算各式生產參數，體驗參數組成如何影響成本、生產效率。最後，生產效率的提升如何創造出競爭優勢，同時可以理解經濟學原理中，生產都會有最低生產成本，及學習規模不經濟理論。

Shen, Sales Manager of Gudeng Precision, received an order of 40,000 cassettes at NT$35 per set, which was 40% off of the ticket price. With the manufacturing cost of each set being NT$82, selling at NT$35 would translate to at least a loss of NT$1,880,000. Shen faced a dilemma, because the capacity utilization of the new factory is too low to dismiss this order, but taking the order would mean a deficit instead of a profit. Shen finally decided to take this order to fill the capacity utilization. To her surprise, this lowest price deal in the industry attracted other customers and orders poured in. Li, Director of Manufacturing, had years of manufacturing experience accrued in Guden Precision, and his expertise in plastic mold design was highly recognized. His calculation showed that with the demand of 2,400,000 sets per year, the optimal mold design is set at the six mold point. With a six-mold design, the lowest injection molding manufacturing cost is attained. Li turned the production which could have resulted in a negative margin (-132.8%) into a profitable production with a high margin (30.71%). This case provides the background knowledge of plastic product manufacturing and mold structure, such as manpowe scheduling, machine tonnage, depreciation amortization, and the revalance between mold size and the manufacting cost. In the situation of large demand for products, the optimization of manufacturing process design reduces the product cost. This case provides students not only the real situation of factory operation, but the caculating production parameters, influencing the production cost and effiency. Students can learn how production effiency creates the competitive advantage. By economic theory, there is a lowest production cost. Also, there are situations that economies of scale no longer function, i.e. diseconomies of scale. This case offers a lens to see the theories in action.

家登精密業務部沈協理一開始因不懂模具最佳化設計成本計算邏輯，對於客戶晶美公司要求一次降價40％，開出從每套58元降價到35元的價格訂單，單方面認為是客戶的刁難。並且，家登內部對2吋晶舟盒市場需求量預估不正確，導致原始模具只採用一模一穴的設計，進而使每套晶舟盒平均成本高達82元。在傳統以ERP支援業務與生產決策的情況下，殊不知這是一個難得的商業機會。 當然，真實狀況是沈協理基於要填補產能的情況下勉強接單，想不到當售價降到市場最低價35元時，卻意外讓訂單量急劇暴增，並經由李廠長及時介入在市場最低售價下，促使市場最大需求量是每月20萬套的情況，一模六穴才是成本最低的最佳化模具設計。其成本改善幅度高達163.51%，將一個原本鉅額虧損的產品變身為毛利率高達30.71%的產品。晶舟盒成本改善效果只取決於做出該開幾穴的模具，並配合相符合的射出機器的決策，熟悉此模具最佳化設計成本計算方法，可為企業帶來巨大的成本改善效益。 從個案中發現直接人工成本是關鍵因素，透過分析最大產量的改變或提高攤提年限等，發現其對成本的改善幅度均有限，而毛利率的瓶頸在於如何削減直接人工成本，雖然一模一穴的模具成本只有35萬，而一模六穴的模具成本是65萬，模具成本增加不到一倍，但是每套晶舟盒的模具攤提成本卻從2.1元降為0.66成本降低達三倍多，但都遠不及六穴直接人工費用從6.04元攀升到八穴的9.05元，所以大量製造之產品投入自動化設備取代直接人工可為企業帶來巨大效益。塑膠模具最佳化設計在單位生產量大時，會有巨幅的成本降低能力。故若製造業能善用此知識定能創造出競爭優勢。 藉此，本文傳授給學生的概念為經濟學原理中所有生產都有最低的生產成本。並教導學生如何找出最低成本，同時也能學習規模不經濟理論；個案中，一模八穴成本之所以會比一模六穴成本高的原因在於規模不經濟。因為不管模具成本、設備成本還有需要配置的直接人力都大幅增加導致規模不經濟。

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