Characterization of magnetic composite fluid polishing removal of fused silica elements

Objective Utilizing magnetic compound fluid (MCF) polishing technology, a comprehensive study was conducted on the polishing process of fused quartz components. The aim was to compare the removal characteristics of fused quartz materials when subjected to traditional MCF and ultrasound-assisted MCF (UMCF) polishing. This comparison aimed to assess the impact of both MCF and UMCF polishing on the removal amount/removal rate of fused quartz materials and surface roughness across various polishing durations. A material removal rate model was formulated, incorporating the effects of polishing stress and duration.

Methods   The polishing characteristics of MCF and UMCF at different times were investigated by five-axis polishing and processing machine tool equipment (Fig.1), the polishing spot cross-section profile test was analyzed on the polished optical components using a surface profiler (Fig.3), and the surface morphology of the processed components was analyzed using a metallurgical microscope and roughness tester (Fig.6).

Results and Discussions The findings of the study reveal that UMCF significantly outperforms traditional MCF in terms of material removal rate enhancement and surface roughness reduction. Both polishing methods operate on the principle of elastoplastic removal. Notably, UMCF achieved a remarkable 68.88% improvement in surface roughness compared to MCF. Attributed to the synergistic effect of hydrodynamic pressure and ultrasonic vibration pressure, the material removal rate of UMCF reaches an impressive 5.74×10⁻³ mm³/min, surpassing MCF by a factor of 3.04. Furthermore, the material removal rates of both MCF and UMCF exhibit a power function relationship with polishing stress and duration. Notably, the influence of polishing stress on the removal rate is more pronounced in UMCF compared to MCF.

Conclusions With the same polishing time, UMCF polishing rather than MCF polishing can be obtained by the greater length, width and depth of the polishing spot. And with the increase in polishing time, MCF polishing material removal rate MRR showed a slow increase in the trend, while the UMCF polishing removal rate showed a rapid decline in the trend of the UMCF polishing in 5 min, MRR can reach a maximum of 5.74 × 10⁻³ mm³/min, 4.04 times that of the MCF polishing at the same time. With the prolongation of MCF polishing time, a certain polishing track will appear on the surface of the component, resulting in poor surface roughness of the component. UMCF polishing did not show obvious polishing track, and the surface roughness Ra decreased to 0.108 μm at 15 min of polishing, which was optimized by 68.88% compared with MCF polishing at the same time; The dynamic pressure of the polishing fluid showed an inverted "W" distribution, which coincided with the spatial geometry of the polishing spot, and the UMCF polishing increased the ultrasonic pressure effect compared to MCF polishing, so the material removal rate of UMCF was high compared to MCF polishing, and the material removal mechanism of MCF and UMCF polishing in this study was elastic-plastic removal; The material removal rate modeling showed that the material removal rate of MCF and UMCF polishing showed power function correlation with both polishing stress and polishing time, and the effect of polishing stress on the removal rate was more weighted in UMCF polishing than in MCF polishing.