Whole Elliptical Surface Polishing Using a Doughnut-Shaped MCF Polishing Tool with Variable Tilt Angle

Abstract

Elliptical elements are essential optical surfaces for modifying optical systems. For polishing the whole elliptical surface using doughnut-shaped MCF polishing tool with variable tilt angle, an experimental investigation was conducted in this work. Firstly, a flat workpiece was polished to determine the polishing feasibility. It was found that the middle portion of the polishing tool had optimal ability to remove materials, and the surface roughness Sa at the material removal peak was changed from 134 nm to 17.5 nm within 50 min of polishing. A smoother surface could be obtained using MCF2 slurry and MCF3 slurry, but the use of MCF1 slurry resulted in a rough surface. Then, the effects of working gap h, revolution speed of MCF polishing tool and polishing time on the polishing results were tested to study the polishing characteristics. Sa 9.6 nm and glossiness 278 Gu were obtained, and form error improved from 2.3 μm to 1.3 μm. Finally, the MCF polishing tool was dried to observe the microstructure of the MCF polishing tool after polishing. Abrasive particles were distributed evenly after polishing. It was seen that the abrasive particles were grabbed by the ferric clusters, and the α-celluloses were interleaved between the clusters.

Experimental investigations on weak magnetization-enhanced force-rheological polishing of SiC mold

“…The former entails physical and chemical reactions and mainly includes ion beam polishing [4,5] and laser polishing [6,7]. The latter entails mechanical action between the abrasive particles and the surface and mainly includes magnetorheological nishing (MRF) [9][10][11][12], ultrasonic-assisted polishing [14,15], bonnet polishing [17,18], and jet-assisted polishing [20][21][22]. Hänsel et al [4] were based on the dwell time algorithm and proved that, after global polishing of an aspheric silicon lens with an aperture of 135 mm by ion beam, the surface shape error was reduced from 4.5 to 0.56 nm.…”

“…After 70 min of polishing, 14.9 nm SR was obtained, realizing the effective polishing of complex curved parts. Feng et al [11] developed an annular magnetic compound uid polishing tool based on variable tilt angle and explored the in uence of process parameters on the surface quality of elliptical elements. The shape error of elliptical surfaces ranges from 2.3 to 1.3 µm.…”