- 學位論文
射出用石膏模具最佳化設計
The Development of Optimal Design of Gypsum Mold for Injection
摘要
本研究為探討射出成型用石膏模具製程之最佳化設計。本研究所提出之石膏模具為用於開發階段中之短暫型模具，藉使用短暫型模具可減少在模具開發的時程，降低成本。 石膏(Gypsum)為一種天然礦物，其用途廣泛並能回收再利用，是有利減少環境衝擊的材料之一。在過去，於工程領域上，因石膏受限於其機械性質(如:抗壓強度)的緣故，僅運用於低壓成型的領域，如澆鑄成型，而射出成型為一高壓成型方式，模具需要有足夠的抗壓強度來承受極大的射出壓力。 石膏模具的機械性質主要受三種因素影響:石膏粉末與水的混水比、製程時的加壓荷重和振盪大小。本文將使用田口實驗設計法來進行此三種因素的最佳製程條件分析，透過製作石膏試片，找出能提升石膏抗壓強度的最佳製程參數。由實驗結果可得，其最佳製程參數組合為:以每公克的粉添加0.375公克的水進行漿體混合，並加入3公斤的重量負荷及323.1瓦的振動大小；且其實驗壓縮強度與預測值得誤差為0.05dB。 本研究所提出之石膏模仁製程參數，可運用於射出成型上，並製作超過100件以上的塑膠射出零件，其證實了在射出成型上，石膏也能作為短暫性模具材料的選擇之一。
並列摘要
A temporary plastic injection mold made of gypsum material is proposed. The advantage of this molding method includes shorter fabrication process, less material cost, and lower impact to the environment. Traditionally, gypsum mold only can be used for low pressure molding process such as casting. The critical requirement for the gypsum mold used in injection process is the compressive strength of gypsum. The ingredient of hemihydrates/water, the applied load, and vibration frequency are three factors that influence the compressive strength of gypsum molds. In this work, we used Taguchi method to determine the optimal parameters for gypsum mold fabrication. The result of experiments revealed that the optimum combination of parameters was for each gram gypsum adding 0.375 gram water to form the mixture under 3 Kg weight load and 323.1 power watt of the vibration. The error of compressive strength from the Taguchi confirmation experiment was 0.05dB compared with the simulation value. The results show that a plastic part made by the gypsum mold in injection process is produced successfully. The lifetime of the gypsum mold can endure over 100 times of use. This work proves that gypsum material can be used as a rapid tool for small quantity production.