塑性微挤压成形力变化规律的实验研究

Experimental investigation on pressure variation during plastic micro-extrusion

针对坯料微型化时,材料的流动应力已不能按照传统塑性加工工艺等比缩小处理问题,采用自行研制的塑性微挤压成形装置,进行微型齿轮挤压实验研究,探讨挤压过程中挤压力的变化规律,分析比较预紧力、挤压速度、摩擦条件对挤压力以及成形试件表面质量的影响。实验结果表明,基于纯铅的常温微挤压实验,预紧力的大小对成形试件的挤出长度影响较大;低应变率时,不同挤压速度下,挤压力无明显变化,材料的率相关性不明显;在不同摩擦条件下,石墨润滑时,挤压力有明显降低,试件表面质量也有较大改善。

During stock miniaturization,the flow stress is different from that of traditional plastic processing,so the experiment of micro-gear extrusion was carried out with self-developed devices to discuss the pressure variation of the process.The analysis and comparison for the influence of preload,extrusion speed and friction of extrusion pressure and the surface quality of the specimen were made.The results show that during the superplastic micro-extrusion of pure lead at room temperature,the pre-tightening force has a greater impact on the extruded length of the specimen;at low strain rates,there are no significant change in extrusion pressure under different extrusion speeds and no significant correlation between strain rate and material;when using graphite for lubrication,extrusion pressure decreases significantly,with the surface quality of the sample being improved.