双磁极式磁粒研磨机理分析及试验研究

Mechanism Analysis and Experimental Study of Dual MagneticPole Magnetic Particle Grinding

目的解决平面磁粒研磨中压力不均匀和需要反复调整研磨间隙的问题,设计双磁极式研磨方法。方法首先对双磁极式研磨方法机理进行分析,并对研磨区域单颗磨粒进行受力分析,寻找影响研磨压力的主要因素;其次利用Ansoft Maxwell软件对两种研磨方法进行磁场仿真,分析两种研磨方法的研磨区域磁场梯度变化,通过面积积分法对比磁感应强度的影响程度;最后设计试验装置,通过试验对理论分析及有限元分析的结果进行验证,对比研磨前后工件表面粗糙度及微观形貌变化。结果双磁极式研磨方法中磨粒的研磨压力完全由磁场力提供,与研磨区域磁感应强度成正比,研磨区域磁感应强度比"铣削式"研磨方法提高约34.56%。两种方法在相同试验条件下对SUS304不锈钢板研磨40 min,双磁极式研磨方法研磨后,工件表面原始纹理基本被去除,表面粗糙度值由原始的0.25μm下降至0.16μm,下降率为36%,比"铣削式"研磨方法提高约80%,粗糙度曲线波动平缓,波峰波谷高度差变化均匀且表面形貌光滑平整。结论双磁极式研磨方法研磨区域磁场梯度变化明显,利于磨粒流动更新,研磨压力相对稳定,表面粗糙度下降率高,研磨后工件表面形貌光整,与"铣削式"研磨方法相比具有较明显的优势。

The work aims to design a dual magnetic pole grinding method to solve the problem of uneven pressure and repeated adjustment of the gap in the process of plane magnetic particle grinding.Firstly,the mechanism of dual magnetic pole grinding method and the force of a single abrasive particle in grinding area were analyzed,in order to find the main factors that affected the grinding pressure. Secondly, Ansoft Maxwell software was used to simulate the magnetic field of two grindingmethods to analyze the magnetic field gradient change in the grinding areas of the two grinding methods, and contrast theinfluence of the magnetic induction intensity in area integral method. Finally, the test device was designed. The results oftheoretical analysis and finite element analysis were verified by experiments. The changes of surface roughness and microstructureof the workpiece before and after grinding were compared. The grinding pressure of the abrasive particle in the dualmagnetic pole grinding method was provided by the magnetic field force completely, which was proportional to the magneticinduction intensity in the grinding area. The magnetic induction intensity in the grinding area of dual magnetic pole grindingmethod was about 34.56% higher than the “milling type” grinding method. The SUS304 stainless steel plate was ground for40 min under the same experimental conditions by two methods. The original textures of the surface of the workpiece wereremoved basically after grinding by dual magnetic pole grinding method. The surface roughness of the workpiece was reducedfrom 0.25 μm to 0.16 μm, with the reduction rate of 36%. The reduction rate of surface roughness of dual magnetic polegrinding method was about 80% higher than the “milling type” grinding method. The surface roughness curve of the dualmagnetic pole grinding method was smooth, the changes of the height difference of the wave crest and wave trough wereuniform, and the surface of the workpiece was smooth and flat. The change of magnetic field gradient in the grinding area isobvious in the dual magnetic pole grinding method. The dual magnetic pole grinding method is beneficial to the renewal ofmagnetic abrasive particles flow, and the grinding pressure is relatively stable. The surface roughness reduction rate of theworkpiece is greatly improved and the surface morphology of the workpiece is smooth after grinding by dual magnetic polegrinding method. It has obvious advantages compared with “milling type” grinding method.