Optimization Study on Multi–Magnetic Pole Coupling Magnetic Field Enhancement Method for Precise Magnetic Grinding of Inner Surface of Aircraft Engine Bend Pipe

A magnetic field strengthening method based on multi-magnetic pole coupling is proposed to address the problems of weak magnetic field strength and low grinding efficiency in traditional magnetic particle grinding technology for processing the inner surface of aircraft engine bent pipes. On the basis of the traditional [Formula: see text] arrangement of magnetic poles with different names, an auxiliary magnetic pole is introduced between the two main magnetic poles, and a slotted spherical auxiliary magnetic pole is added inside the tube to construct a multi-pole coupled magnetic field strengthening system. Conduct simulation analysis and experimental research on auxiliary magnetic pole magnetic fields with different magnetic pole arrays and slot widths. By optimizing the Halbach array main magnetic pole and adding a 0.8 mm wide auxiliary magnetic pole with a spherical slot inside the tube, the magnetic flux density in the grinding area can be effectively increased and the grinding pressure can be improved. By increasing the magnetic induction intensity in the grinding area, the flowability of the magnetic abrasive particles is effectively enhanced, promoting the renewal of the cutting edge and thus improving the service life of the magnetic abrasive particles. The original defects on the inner surface of the bent pipe fittings are almost completely eliminated, and the microstructure is significantly optimized. The surface roughness curve also tends to be smooth, and the roughness stabilizes at Ra 0.171 [Formula: see text] m. Research has shown that the Halbach array and the multi-pole coupling magnetic field strengthening method with spherical slotted 0.8 mm wide auxiliary magnetic poles added inside the tube can achieve optimal surface quality while ensuring processing efficiency, making it the best choice for precision grinding of magnetic poles in aircraft engine bent pipes.