Study On Planar Magnetorheological Electromagnetic Coil Excitation Device Design And Polishing Process

With the rapid development of semiconductor industry and the popularization of digital products such as mobile phones and cameras,the demand for large area and high precision planar components such as IC substrates and mobile phone panels is expanding.The components obtained by traditional processing methods are often accompanied by insufficient surface accuracy,sub-surface damage and high surface roughness.Magnetorheological polishing technology can not only avoid these problems,but also efficiently process super smooth surface.In this paper,a set of electromagnetic excitation device is designed,and under this condition,polishing experiments on K9 glass,silicon carbide wafer and silicon wafer are carried out.The main research contents are as follows:(1)A set of excitation device applied to the experimental platform is designed.By analyzing the characteristics of the excitation mode,the electromagnetic coil excitation mode is selected.According to the application requirements and polishing principle,the material selection and structure design of the yoke are carried out.According to the magnetic field principle of the excitation device,the structure size of the excitation device is determined.(2)Maxwell 16.0 software is used to simulate and optimize the structure size of the excitation device.The model is built by Maxwell 16.0 software,and the magnetic field generated by different excitation devices is simulated to optimize.The structure of arc yoke instead of traditional linear yoke is proposed,chamfer structure is introduced,and the size parameters of excitation device are optimized by orthogonal design.By comparing the magnetic field produced by the device before and after optimization,the ploughing groove phenomenon on the surface of the workpiece after processing is eliminated,and the magnetic field intensity in the processing are a is increased by 27%,and the magnetic field width is increased by 26.2%.(3)Magnetorheological polishing process experiment was carried out.The single factor experiment method was used to design the experiment of four parameters: the speed of the polishing disc,the speed of the workpiece,the working gap and the working current.The process parameters of polishing were analyzed and optimized.After polishing K9 glass,the material removal rate reached 0.93 mg/min,and the ultra-smooth surface with surface roughness of Ra0.72 nm was obtained.The polishing experiments on silicon wafer and silicon carbide wafer were carried out,and the ultra-smooth surface with surface roughness of Ra0.37 nm and Ra0.79 nm was obtained.