Experiments on relative angles of grinding two sides of involute pole groups

Abstract

Objectives: Titanium alloys are increasingly widely used in the aerospace field, and their research and development significantly influence the advancement of military aircraft, civil aviation, engines, and other high-tech equipment. However, titanium alloy are challenging to machine due to theri small deformation coefficient, low thermal conductivity, and the high temperatures generated during traditional cutting methods, which leads to tool wear. As a result, parts often have low precision, and surface quality is generally poor. This study proposes a double-sided magnetic abrasive finishing (MAF) method using opposing magnetic pole sets with adjustable relative angles to address surface defects—such as bumps, scratches, and microcracks—on the surface of titanium alloy TC4 and to improve its grinding efficiency. Methods: This study compares three types of lined magnets and introduces an involute-lined magnet design. Based on this design, opposing magnetic pole sets are used to generate an initial relative angle between them. The effects of different relative angles on double-sided MAF are tested to determine whether this method can improve the magnetic induction intensity and promote a more uniform distribution of abrasives. The results show that this approach addresses the challenges of poor abrasive fluidity and the inability of abrasives to tumble effectively. Additionally, the simultaneous grinding of both sides of the workpiece enhances processing efficiency, effectively removes the surface defects of the workpiece, and improves the grinding efficiency and surface quality. Results: The application of involute-lined magnets with a relative angle for double-sided MAF yields improved processing results under the following test conditions: magnetic pole group speed of 600 r/min, processing gap of 2 mm, magnetic abrasives size of 150 μm, and a relative angle of 10°. After 30 minutes of grinding, the surface roughness of the front side of the titanium alloy is reduced from Ra 0.458 μm to Ra 0.116 μm, and the surface height variation decreases from 43.3 μm to 7.8 μm. The reverse side also shows improvements, with surface roughness decreasing from Ra 0.434 μm to Ra 0.111 μm, and surface height variation reducing from 44.2 μm to 8.4 μm. Conclusions: The use of involute-lined magnets to create a relative angle for double-sided grinding effectively improves surface defects, such as scratches and grooves, on the workpiece. This method also significantly enhances grinding efficiency compared to single-sided grinding. The involute arrangement of magnets minimizes variations in magnetic induction intensity, which improves grinding efficiency and ensures a more uniform distribution of the magnetic field. This uniformity results in better adsorption of magnetic abrasives and enhanced grinding quality. When grinding at a relative angle of 10°, the magnetic field gradient changes significantly, covering a wider area with stronger magnetic induction. This variation in magnetic field gradient faciliates the tumbling of magnetic abrasives and the timely renewal of cutting edges, ultimately improving processing performance.

Keywords

• double-sided magnetic particle grinding
• magnetic pole design
• relative angle
• gradient contrast
• surface quality