弹性磁极磨头磁力研磨TC4钛合金的工艺优化

Process optimization of magnetic grinding TC4 titanium alloy with elastic magnetic pole grinding head

尽管磁力研磨具有随形加工特性,但使用小磨头磁力研磨大扭曲度工件时,磨头在工件不同位置处的间隙差异,给磁力研磨加工带来了挑战。为了改善磁力研磨的加工表面质量,进一步减小工件间隙差异对表面粗糙度的影响,设计了一种以聚氨酯弹性体为磁极载体的弹性磁极磨头,对其磁场进行仿真分析并验证。在试验中使用黏结法制备的金刚石磁性磨料,比较不同加工间隙下聚氨酯弹性磁极磨头与普通磁极磨头的研磨加工性能,探索主轴转速、进给速度和磨料粒度对钛合金表面粗糙度的影响规律。结果表明:在工艺参数相同的情况下,聚氨酯弹性磁极磨头的加工性能优于普通磁极磨头的;使用聚氨酯弹性磁极磨头,在主轴转速为800 r/min,加工间隙为2.0 mm,进给速度为5 mm/min,磨料粒径范围为62~90μm时,磁力研磨加工效果最优,经过12 min的研磨加工,TC4钛合金的表面粗糙度R_(a)从最初的0.350μm降至0.039μm,表面粗糙度改善率达到89%。试验结果验证了聚氨酯弹性层的弹性及仿形特性对TC4钛合金加工表面质量的提升作用。

Magnetic grinding has the characteristics of conformal machining.However,when a small grinding head is used to magnetically grind a workpiece with a large twist,the difference in the gap between the grinding head at different positions of the workpiece poses a challenge to the magnetic grinding process.In order to improve the surface quality of magnetic grinding and further reduce the influence of the gap difference between the grinding head and the workpiece on the surface roughness,an elastic magnetic pole grinding head with polyurethane elastomer as the magnetic pole carrier was designed,and its magnetic field simulation analysis and verification were carried out.In the experiment,the self-made diamond magnetic abrasive was used to compare the grinding performance of the polyurethane elastic magnetic pole grinding head and the ordinary magnetic pole grinding head under different machining gaps.The influence of the process parameters such as spindle speed,feed rate and abrasive particle size on the surface roughness of the workpiece was studied experimentally.The experimental results show that under the same process parameters,the processing performance of the polyurethane elastic magnetic pole grinding head is better than that of the ordinary magnetic pole grinding head under different machining gaps.Using polyurethane elastic grinding head,when the spindle speed is 800 r/min,the machining gap is 2.0 mm,the feed speed is 5 mm/min,and the abrasive particle size is 62 to 90μm,the magnetic grinding effect is the best.After 12 minutes of grinding,the surface roughness R_(a) of TC4 titanium alloy can be reduced from the initial 0.350μm to 0.039μm,and the surface roughness improvement rate reaches 89%.The results verify the effect of the elasticity and profiling characteristics of the polyurethane elastic layer on the quality of the machined surface.