金屬粉末射出成型(MIM)適合製作形狀複雜之零件，如筆記型電腦的樞紐轉軸，相對於鑄鍛加工產品，MIM 之標準材料相當少，且具高強度者更遠少於鑄鍛件，故本計畫之目的在於調整喂料配方，評估將超硬合金粉末應用在MIM製程的可行性，進而探討在不同的射出參數與燒結溫度下之成型品之力學性能的影響，並藉由顯微結構的觀察分析MIM合金微結構之變化，以確保後續MIM合金品質之良窳。本實驗採用鉬-鐵-硼或鎳-硼粉末，再添加巴斯夫4605與聚甲醛基黏結劑，經混煉造粒後，以射出成型法製作生胚，再經催化脫脂後成為棕胚，最後放置於負壓爐中燒結;本實驗的主要目的即是藉由製備喂料配方與控制燒結溫度兩方向來改善MIM成型品的硬度及強度，且將藉由顯微結構的分析深入了解MIM合金強化之機制。計畫中除了實驗射出製程參數對成型品特性影響的探討外並且將開發CAE分析模擬技術，藉由材料測試建立MIM配方之剪切黏度資料庫，掌握其流動行為來協助模具設計，預期可有效改善粉膠分離的缺陷、均勻控制收縮翹曲變形、提升品質穩定性、成型良率，本計畫最終目的是利用此方法提供筆電樞紐轉軸製程之參考，達到美國粉末冶金協會MPIF-35的力學性能要求。 ;Metal injection molding (MIM) is a widely used manufacturing process of complex-shaped products, such as the hinge component in laptop. Compare with the casting and forging processes, the standard material of MIM has less hardness than that of casting/forging process. The aim of this proposal is thus to evaluate the feasibility of applying the superhard alloy powder to MIM through a modified prescription of feedstock. Furthermore, effects of injection parameters and sintering temperature on the mechanical performance of end product will be investigated. In order to ensure the quality of MIM alloy, its microstructure variations will be observed through the microscope.This experiment may utilize the gas atomization to produce the Mo2FeB2 or NiB powder. The powder is then custom formulated with BASF Catamold® 4605 and POM-based binder into a feedstock via kneading and granulating. The feedstock is injected as a melted liquid into a mold using plastic injection machines. After cooling, the green part is ejected from the mold. Subsequently, most of the binder is extracted using a catalytic debinding process, resulting in the brown part. Finally, the brown part is transferred into the sintering furnace under a controlled atmosphere. The objective of this experiment is to improve the hardness and the strength of end-product metal through feedstock preparation and temperature control sintering. The strengthening mechanism of MIM alloy will be investigated through the analysis of microstructure.In this proposal, not only will the injection molding experiment be carried out, but the CAE analyses will also be developed to help the mold design and understand the flow behavior of powder-binder mixtures. Injection parameters such as melt temperature, mold temperature, injection speed, etc. will be investigated their influence on the end-product characteristics and qualities. Rheological and thermal properties of melted feedstock will be measured for accurate CAE simulation. It is expected that the defect of powder-binder separating, uniform shrinkage, stable quality and productivity can be greatly improved. Ultimately, this methodology may serve as a reference for manufacturing hinge components having mechanical properties according to MPIF Standard 35.
