Abstract
在本研究中，主要針對金屬粉末射出成形製程作一系統化之研究。包括黏結劑配方的選用、射出成形參數的選擇、標準脫脂行程之決定、燒結氣氛的影響、燒結溫度對胚體組織的影響。黏結劑組成以聚丙烯、石蠟、棕櫚蠟、硬脂酸為主，經與羰基鐵粉進行熱混煉後作成塑料，做為射出成形時使用。射出成形時，射出成形參數的選擇，藉由田口式實驗對胚體重量及厚度大小進行觀測，由 S/N比與平均值之大小或趨勢，選擇射出成形控制參數，可改善射出胚體的品質。脫脂過程中，除了使用氮氣做為保護氣氛，在主要脫脂區間以慢速溫昇速率及階段性持溫進行脫脂控制，可得良好的脫脂結果。燒結溫度對胚體緻密過程比對燒結時間的控制來的大，研究中以燒結溫度作為控制條件，實驗結果顯示高的燒結溫度下可增加胚體緻密化的程度且提高胚體密度，但卻造成晶粒的粗化現象。The purpose of this study is to make a systematic study onthe process of the metal powder injection molding. Theentire process consists of binder system selection, injectionmolding conditions selection, debinding profile's setting, andeffect of sintering atmosphere and temperature. In theexperimentation, a standard binder system mainlyconsists of polypropylene, paraffine wax, carnauba wax,and stearic acid. The feedstock is made by mixture of thecarbonyl iron with the standard binder system. The conditionsof the injection molding are set up using the Taguchi'sExperiment Design for improve the green body quality. Duringthe debinding process, the results show that debinding couldbe finished without defects when using multi- stagescontrol with slow heating rate and temperature holding undernitrogen atmosphere. In the sintering process, temperature ismore important than time, therefore the difference among thesintered bodies in microstructure are viewed underdifferent sintering temperatures. These results show thathigher tempera- ture sintering process produces a high densityand desification level but coarser grain.