金屬粉末射出成型技術(MIM)其兼具高量產性與高複雜性的優勢使此製程在精密金屬零件的生產具有一席之地，射出成型階段的控制將是影響品質的重要因素，且其喂料是由黏結劑與粉末組成的特殊結構也使流變性質更難以掌握，尤其在流動過程中易產生粉膠分離之情形。本研究採用模流分析進行參數最佳化，針對產品生胚變形量，以及MIM特有的粉末濃度均勻性問題做改善。 分析流程主要可分兩大階段，第一階段初步執行模擬並驗證產品短射實驗，以及製作射出成型之成型視窗；第二階段採用田口方法之實驗設計，針對變形量以及粉末濃度均勻性進行兩次的最佳化分析。 第一階段分析結果顯示，產品實際射出與模擬之短射比對具有相似的趨勢，其結合線位置也可以有很好的預測。經Moldex3D實驗設計模組(DOE)最佳化結果顯示，針對翹曲變形量最大可達11.6%的改善率，其最佳化參數經實驗結果證明確實獲得改善，且實驗結果之改善率最大幅度來到57.78%，各區域之平均改善率也達到20%，再者，透過此最佳化參數配置相較原始組別可減少3秒的循環時間，對尺寸品質以及生產效率帶來明顯效益。 粉末濃度均勻性最佳化前顯示，原始組別其粉末濃度百分比位於56.8169% 至62.7930%，平均粉末濃度為60.0313%；經最佳化後之組別其粉末濃度百分比位於58.6520% 至60.2703%，平均粉末濃度為60.0145%，其粉末濃度有更好的均勻性，說明了此參數調整可減少局部粉末堆積或粉體膠體分離之情形。 ;Metal Injection Molding (MIM) has taken a place in the production of precision metal parts due to the advantages of high productivity and high complexity. Control of the injection molding stage, the quality, and the feedstock is the important issue. Especially for combination of feedstock which is composed of binder and metal powder also makes the rheology more difficult to know. The situation of powder binder separation often occurs during the filling process. In this study, molding simulation was used to optimize the parameters, and to improve the problem of green parts warpage and powder concentration uniformity for MIM. The analysis process is separated into two major stages. In the first stage, the initial simulation is performed to verify the short shot of experiments. Furthermore, the working window for injection molding is established. In the second stage, the experimental design of the Taguchi method is adopted to get the optimization for warpage and powder concentration uniformity. The results of first stage show that the experimental short shot similar to simulated one. In addition, the position of the welding line can also be well predicted. The optimization results of the Moldex3D Design of Expert (DOE) show that the maximum improvement on warpage achieves 11.6%. When these optimized parameters are used in experiments, the maximum improvement on warpage can achieve 57.78%, and the average improvement achieves 20%. Moreover, the optimized parameters can reduce the cycle time of 3s compared with the original design, which brings significant benefits to the dimensional precision and production efficiency. Before optimization of powder concentration uniformity, the original powder concentration percentage was between 56.8169% and 62.7930% and its average powder concentration was 60.0313%. After optimization, the powder concentration percentage is between 58.6520% and 60.2703% and its average powder concentration is 60.0145%. Therefore, the powder concentration becomes uniform. In other words, this parameter adjustment can reduce the local powder accumulation or the powder binder separation.
