微机电产品零件粉末注射成形
发布时间：2019-06-17 14:54
【摘要】：本文以生产性能符合要求的微齿轮为目标，研究了粒度D10为1.96μm，D50为3.81μm，，D90为9.92μm的羟基铁粉的粉末注射成形工艺。粘结剂采用以石蜡为基体的热塑性粘结剂体系。其中石蜡和聚乙烯的质量分数分别为50%和45%。分别研究了粉末的粒度分布、最佳粉末装载量、喂料的流动性能、脱脂工艺、烧结工艺、制件力学性能、微齿轮模流分析及微齿轮模具设计。研究表明： 粉末的粒度分布较宽、颗粒细小，具有很好的成形性能及烧结性能。粉末的装载量越高喂料的流动性越差，52.54%为喂料的最佳粉末装载量。最大注射压力为50Mpa，注射压力超过50Mpa时制件会产生明显的飞边。注射成形件非常均匀，其密度为4.5g/cm3。 在45℃的正庚烷中溶剂脱脂，约第18h时石蜡已经脱除80%以上，连通孔隙已经打通。热脱脂升温速率快时坯件会产生明显的变形。采用慢速升温、分段保温的加热工艺可得到形状保持良好、脱脂完全的坯件。最佳升温工艺为：从室温到420℃的过程中平均升温速率为0.5℃/min,从420℃～650℃的过程中，平均升温速率为1℃/min。其中在140℃、250℃、420℃、500℃、650℃分别保温0.5h、1h、3h、2h、1h。 烧结温度在1230℃～1260℃之间所得制件力学性能最佳。硬度（HRB）平均为67、收缩率平均为18.5%、晶粒直径为30.87μm。当烧结温度低于1230℃时制件孔隙较多，力学性能较差，。当烧结温度超过1260℃时由于晶粒的明显长大，力学性能也会明显下降。 用Moldflow软件模拟的微齿轮最佳浇口形式为矩形、最低注射压力为18.7Mpa。注射时间为1.2s，保压时间为10.8s。根据模拟结果设计出微齿轮成形模具。根据总结出的工艺原则上可以生产出性能符合要求的微齿轮。
[Abstract]:In this paper, the powder injection molding process of hydroxyl iron powder with particle size D10 of 1.96 渭 m, D50 of 3.81 渭 m and D90 of 9.92 渭 m has been studied in order to meet the requirements of microgears. The binder adopts thermoplastic binder system based on paraffin wax. The mass fraction of paraffin wax and polyethylene were 50% and 45%, respectively. The particle size distribution of powder, the optimum powder loading, the flow performance of feed, defatting process, sintering process, mechanical properties of parts, microgear die flow analysis and microgear die design were studied respectively. The results show that the particle size distribution of the powder is wide, the particles are fine, and the powder has good formability and sintering properties. The higher the powder loading is, the worse the mobility of the feed is. 52.54% is the best powder loading. The maximum injection pressure is 50 MPA, and when the injection pressure exceeds 50 MPA, the parts will produce obvious flying edges. The injection molding part is very uniform, and its density is 4.5 g / cm ~ 3. At 45 鈩
本文编号：2501068
[Abstract]:In this paper, the powder injection molding process of hydroxyl iron powder with particle size D10 of 1.96 渭 m, D50 of 3.81 渭 m and D90 of 9.92 渭 m has been studied in order to meet the requirements of microgears. The binder adopts thermoplastic binder system based on paraffin wax. The mass fraction of paraffin wax and polyethylene were 50% and 45%, respectively. The particle size distribution of powder, the optimum powder loading, the flow performance of feed, defatting process, sintering process, mechanical properties of parts, microgear die flow analysis and microgear die design were studied respectively. The results show that the particle size distribution of the powder is wide, the particles are fine, and the powder has good formability and sintering properties. The higher the powder loading is, the worse the mobility of the feed is. 52.54% is the best powder loading. The maximum injection pressure is 50 MPA, and when the injection pressure exceeds 50 MPA, the parts will produce obvious flying edges. The injection molding part is very uniform, and its density is 4.5 g / cm ~ 3. At 45 鈩
本文编号：2501068
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