| FU Lin,SHAO Lan-ying,YANG Ju-ru,LYU Bing-hai,DENG Qian-fa,WANG Xu.Optimization Experiment for Shear Thickening Polishing of Spherical Roller[J],52(1):232-241, 265 |
| Optimization Experiment for Shear Thickening Polishing of Spherical Roller |
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| DOI：10.16490/j.cnki.issn.1001-3660.2023.01.024 |
| KeyWord:spherical rollers shear thickening polishing surface roughness coefficient of friction |
| Author | Institution |
| FU Lin |
College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou , China |
| SHAO Lan-ying |
College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou , China |
| YANG Ju-ru |
College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou , China |
| LYU Bing-hai |
College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou , China |
| DENG Qian-fa |
College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou , China |
| WANG Xu |
College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou , China |
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| Abstract: |
| The work aims to study the effects of polishing parameters on the surface roughness in the shear thickening polishing (STP) process of spherical roller to obtain smooth surface of spherical roller and optimize the polishing parameters. The effects of four process parameters on the surface roughness of spherical were analyzed, including the types of abrasive, the abrasive concentration, the polishing speed and the polishing distance. Taguchi method was used in the experiment, and the surface roughness was used as evaluating indicator to analyze the influence of the four parameters. The signal-to-noise ratio (S/N) of experimental results was calculated to obtain an optimized combination of process parameters. The frictional wear properties of the polished surface were tested by friction and wear experiments. With the increase of the polishing speed, the polish efficiency increased firstly and then decreased, because the high centrifugal force caused by the high polishing speed resulted in a reduction of abrasive particles in the processing area. An increase in the concentration of abrasive can increase the number of abrasive particles involved in processing, but the concentration of abrasive particles also affected the rheological properties of the polishing slurry, the thickening effect of polishing slurry decreased with the increase of abrasive particle concentration, and the polishing effect was the best when the abrasive particle concentration was 10%. Polishing slurry with mixed abrasive of 1∶1 SiO2/Al2O3 can be more effective in removing workpiece surface defects compared with single Al2O3 or SiO2 abrasive. On the one hand, nano-SiO2 enhanced the oxidation rate of the workpiece surface material in the acid polishing solution, and reduced the strength of the workpiece surface material. On the other hand, Al2O3 abrasive grains and SiO2 abrasive grains further improved the mechanical removal rate of abrasive grains. The polishing distance affected the shear force of the polishing slurry in the processing area. When the polishing distance was 2 mm, the polishing slurry between the workpiece and the polishing tank was solid-like under the action of strong shear force, and cannot pass through the machining gap continuously, and the polishing slurry was completely blocked between the workpiece and the polishing tank. When the polishing distance was 6 mm, the shear force of the polishing slurry was weakened, and the shear thickening effect of the polishing slurry was reduced, resulting in a decrease in the polishing effect. Compared with the polishing distance of 2 mm and 6 mm, polishing slurry had better fluidity and thickening effect when polishing distance was 4 mm. Under the optimized polishing conditions with mixed abrasive of 1∶1 SiO2/Al2O3, abrasive concentration 10%, polishing speed 70 r/min, and polishing distance 4 mm, the surface roughness Sa of the spherical roller decreased from (40±10) nm to (8.51±2) nm in 30 minutes' polishing. STP can effectively remove defects on the roller surface and improve the surface quality, and the polishing process does not change the roundness of the roller. The friction coefficient of the roller surface after polishing is reduced, and less oxide layer is generated and accumulated on polished surface compared to the surface before polishing. The results show that STP method can improve the surface quality of spherical roller effectively. |
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