薄壁铜管旋转模压法缩径成形质量实验与仿真研究

Experimental and simulation study on quality of thin-wall copper tube after tube sinking with a rotatory die

旋转模压缩径工艺是薄壁铜管制造超薄微热管的重要工序,针对外径为Φ5 mm、壁厚为0.1、0.2、0.3 mm的铜管,通过实验探究了模具转速、模具进给速度与铜管壁厚3个参数对缩径成形质量的影响。结果表明,该工艺下,铜管表现出3种成形现象:顺利成形、规则压溃及弯折。在其余参数一定的情况下,增大模具进给速度会使铜管发生从顺利成形到规则压溃、再到弯折的转变,并减小已成形区长度。增大模具转速会提高已成形区长度与临界进给速度。铜管壁厚的增加在一定程度上可以提高转折长度:铜管壁厚由0.1 mm增加至0.2 mm时,提高效果明显,但由0.2 mm增加至0.3 mm时,无明显变化。实验中的最优工艺参数为:模具转速为4800 r·min^(-1),模具进给速度为50 mm·s^(-1),可兼顾成形质量与生产效率。基于ABAQUS有限元软件建立铜管旋转模压缩径仿真模型,辅助分析成形过程并验证了实验结果。

The tube sinking with a rotatory die is an essential process for thin-walled copper tube to manufacture ultra-thin micro heat pipe.For the copper tubes with the outer diameter of Φ5 mm and the wall thickness of 0.1,0.2 and 0.3 mm respectively,the influences of die rotation speed,die feed speed and wall thickness of copper tube on the quality of tube sinking were studied experimentally.The results show that under this process,the copper tubes have three forming phenomena such as smooth forming,regular crushing and bending.When the certain other parameters are fixed,increasing the die feed speed causes the copper tube to undergo a transition from smooth forming to regular crushing,then to bending,and reduces the length of formed area.Then,increasing the die rotation speed enlarges the length of formed area and the critical feed speed.And increasing the wall thickness of copper tube magnifies the bending length to a certain extent.When the wall thickness of copper tube is increased from 0.1 mm to 0.2 mm,the improvement effect is obvious,but when the wall thickness of copper tube is increased from 0.2 mm to 0.3 mm,there is no significant change.In the experiment,the forming quality and the production efficiency are both good under the optimal process parameters with the die rotation speed of 4800 r·min^(-1) and the die of feed speed for 50 mm·s^(-1).Thus,based on finite element software ABAQUS,the simulation model of tube sinking with a rotatory die for copper tube is built up to assist the analysis of the forming process and verify the experimental results.