基于液体磁性磨具的相对式磁极头设计及实验研究

Design and Experimental Study of Opposite Magnet Pole Based on Fluid Magnetic Abrasives

目的研究磁极头的形状和工作方式,以提高液体磁性磨具对铝合金板的加工均匀性和加工效率。方法首先对液体磁性磨具光整加工机理进行分析,并对上磁极头进行理论分析计算,据此提出三种上磁极头设计方案,同时对磁极头最佳运动方式做出阐述,然后使用Maxwell仿真软件进行磁场仿真,根据最佳方案搭建实验平台,进行光整加工实验。结果根据仿真结果确定,采用镶嵌分布瓦形永磁体的方式设计磁极头,并使上下相对布置的磁极头同步旋转,可以使磁场能量聚集在加工区域,磁感应强度最高的部位可达0.42 T,从而增强磁极头对液体磁性磨具的带动作用,提高加工效率。对铝合金平板的加工实验表明,磁极头转速越大,工件表面粗糙度值Ra下降越快,铝合金平板表面粗糙度值从0.8μm降到了0.3μm,但是当磁极头转速达到606 r/min时,其加工效果开始变差,因此加工时应根据工件表面质量要求选择适当的转速。结论使用基于液体磁性磨具的相对式磁极头对铝合金平板进行表面光整加工,可以提高加工均匀性和加工效率。

The work aims to study the shape and working mode of magnet pole so as to improve the uniformity and processing efficiency of fluid magnetic abrasives on flat aluminum alloy plate. First, the finishing mechanism of fluid magnetic abrasives was analyzed, and the upper magnet pole was analyzed and calculated theoretically. On this basis, three design schemes of upper magnet pole were proposed, and the optimal motion mode of magnet pole was described. Then, the simulation of magnetic field was conducted by Maxwell simulation software and the experimental platform based on the best scheme was set up to finish the experiment. From the simulation results, the magnet pole was designed by distributing embedded tegular permanent magnet. At the same time, the two opposing magnet pole rotated simultaneously to concentrate magnetic energy in the processing area. The highest magnetic induction intensity could reached 0.42 T, thus enhancing the driving effect of magnet pole on fluid magnetic abrasives and improving the efficiency. The results of the machining experiment for flat aluminum alloy plate showed that the larger the rotating speed of the magnet pole was, the faster the reduction of the workpiece surface roughness value Ra was, because the surface roughness of flat aluminum alloy plate decreased from 0.8 μm to 0.3 μm, but when the speed of magnet pole reached 606 r/min, the processing effect began to deteriorate. Therefore, a suitable rotation speed should be selected according to the requirement of workpiece surface quality during processing. Using the opposite magnet pole based on fluid magnetic abrasives to finish the surface of flat aluminum alloy plate can improve the uniformity and processing efficiency.