Ultrasonic Magnetorheological Composite Polishing Process Of Fused Silica

Fused silica has excellent physicochemical properties such as thermal stability,light transmission and chemical stability,and its applications are becoming more and more widespread.The demand for high-quality processing of its surface is increasing,but its hard,brittle and fragile nature makes it difficult to process by conventional methods.In this paper,the surface of fused silica is processed by means of ultrasonicmagnetorheological polishing,and the polishing paths and material removal functions are solved;an undermounted ultrasonic-magnetorheological polishing device is designed,the magnetic field generation device is simulated and the optimal arrangement is determined;the composite magnetic particles are prepared and characterised using the sol-gel method;the multi-component magnetorheological solution is configured and tested for rheology and sedimentation;the polishing of Polishing experiments were carried out on fused silica samples to analyse the influence of different factors on the surface quality:1.According to the movement characteristics of the polishing method of the experimental equipment,establish the single abrasive polishing path,the polishing path is simulated,from the results it can be seen: the polishing path is mainly related to the polishing speed and feed rate,the theoretical derivation of the ultrasonic-magnetorheological compound polishing removal function,to obtain specific expressions,to provide theoretical guidance for the later polishing experiments.2.The design of an under-mounted ultrasonic-magneto-rheological compound device,the selection of the mounting position of the carrier disc and polishing sample;the magnetic field generation device using the grade N30 permanent magnet,different combinations of arrangements and simulation,the results show that: the use of spaced magnetic pole arrangement and the interval distance of 1mm,the magnetic field distribution is uniform,and the magnetic field strength can reach 480 m T,to meet the requirements of use.3.The CIP@SiO2 composite magnetic particles were prepared and characterised by the sol-gel method,and the results showed that the method can uniformly coat the surface of carbonyl iron powder with a silicon dioxide shell.The shear stress and viscosity of CIP magneto-rheology solution are higher than those of CIP@SiO2magneto-rheology solution when the magnetic particle content is the same;the shear stress of CIP@SiO2 magneto-rheology solution is slightly higher than that of CIP magneto-rheology solution under the condition of no magnetic field;regarding the antisettling property,the SiO2 shell is not conducive to the stability of magneto-rheology solution,and the free SiO2 can significantly improve the rheology of magneto-rheology solution,and the content is best at 6v%.4.A single-factor polishing process experimental study was carried out using fused silica as the polishing sample.The conclusions are as follows: the maximum material removal efficiency was achieved at a feed rate of 500mm/min,a polishing speed of800r/min,a diamond grain with a concentration of 6v% and a polishing gap of 0.4mm,and a lower surface roughness in a shorter period of time;using a CIP@SiO2 magnetorheological fluid with a concentration of 35v%,a polishing gap of 0.6mm,a feed rate of 300mm/min and polishing speed of 600r/min,the surface scratches were the least and the quality was the best.