微挤压成形数值模拟

Numerical Simulation of Micro-extrusion

针对微挤压成形中冷热成形的不足,在微挤压成形中采用了温挤压工艺,并简述了微挤压工艺的国内外研究现状。为了探索坯料在微挤压筒内的流动行为,利用有限元分析软件ABAQUS/Explicit模块对微挤压成形进行了数值模拟,从等效应变分布、应力分布和挤压力变化等方面来分析挤压速度对成形性能的影响,结果表明通过改变挤压速度可以改善工件内部的变形不均匀性,挤压速度对应力分布影响不明显,严格控制挤压速度会有效减小挤压力。最后定义了挤出端凸度,并以此作为标准来评定微挤压件的成形性能,挤出端凸度越小则成形性越好。

With the development of MEMS, the demands of micro-extrusion are increasing gradually. However, some problems such as the unavoidable scale effect occurring in miniaturization challenge the plastic process, mechanics and equipment. Warm micro-extrusion process is presented and the development of micro-extrusion is discussed. ABAQUS/Explicit FEM software is used to simulate the micro-extrusion to obtain the flow behaviour of the material in receptacle. The influences of equivalent stress, strain and extruding force on formability are investigated. It is found that the deforming non- uniformity in work can be improved through changing extruding velocity, the influence of extruding velocity on stress distribution is not obvious, the control of extruding velocity can reduce the extruding force effectively. Finally, the standard of convexity of extruding parts is initialized to evaluate the formability of micro-extrusion.