Magnetorheological finishing (MRF) is usually used to remove subsurface defects (SSD) of workpieces to improve the laser-induced damage threshold due to its low stress. Although MRF has been widely used to remove surface defects and SSD, the evolution and removal mechanism of surface scratches under MRF have not been fully elucidated. A systematic study is conducted on the scratch removal process and removal ability of MRF. First, an experimental study on the removal of scratches with different depths is carried out, and the effect of the scratch depth on the removal efficiency is analyzed. Second, when the scratches are removed, the processing is performed in two directions: parallel and perpendicular to the scratch. Thereby, the relationship between the scratch removal efficiency (SRE) and the processing direction is analyzed. Finally, based on the scratch removal process and mechanism, an innovative method for efficient scratch removal using a sacrificial layer is proposed. The effectiveness of this method is verified by experiments. This method can significantly improve the SRE of MRF.
To achieve the super-smooth surface of the fused silica via using the magnetorheological finishing (MRF) technique, the synergistic effect of the rotational speed, viscosity, and working gap is well investigated. According to the pressure field simulation based on the two-dimensional Reynold equation, the working gap is of remarkable importance to the surface roughness among three parameters. Furthermore, such result is also revealed by the MRF experiment. Accordingly, the optimized process parameters are identified, and the final surface roughness is achieved as low as 0.22 nm.
One of the important factors that affect the polishing results is the motion modes of the polishing pad in the process of Computer Controlled Optical Surfacing (CCOS). This paper presents a systematic study for the motion modes in CCOS by using a polishing pad. A series of theoretical and experimental studies have been undertaken to investigate the influences of two typical motion modes, called planet motion and orbital motion, on the polished surface, regarding to material removal rate (MRR), middle-spatial-frequency errors, surface roughness, etc. Firstly, the theoretical removal function of the two motion modes was established, and the experiments were carried out by given polishing parameters. A comparison was made between the results of experiments and simulations by the established polishing model. Then, the effects of the mentioned two motion modes on middle-spatial-frequency errors were simulated by the numerical superposition method, and the results were also verified by actual polishing results. Finally, the surface roughness generated by the two different motion modes was examined and compared. The research work shows that the planet motion has higher material removal rate, lower middle-spatial-frequency errors and lower surface roughness, by compared with orbital motion mode, which is helpful for optimizing the polishing strategy during CCOS.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.