Study On Single-Sided Plane Lapping Of New Driving System

As an important way to obtain high quality surface such as optical glass,sapphire substrate and silicon wafer,plane lapping and polishing is widely used in microelectronics,optics,aerospace and other fields.As a prerequisite for obtaining super smooth surface,lappinging has been widely used in super precision machining and has been widely developed and valued.In this paper,the circular arc swing driving with irrational rotational speed ratio plane lapping is proposed,which can improve the surface uniformity of the workpiece and realize the wear uniform of the lapping plate.It is of great scientific value to enrich the theory of lapping grain processing with high precision shape control and low damage control.In this paper,a new single-plane lapping method of driving mode is put forward.Based on the circular arc swing driving lapping method under irrational rotational speed ratio,the uniformity of motion trajectory is deeply studied,and the test platform is designed and built independently to carry out elevant experimental research.The main research work of this paper is as follows:(1)Based on the plane kinematics principle and using the vector method,the movement trajectory of abrasive particles and the movement trajectory of workpiece are modeled and analyzed,and the motion equation and velocity equation are established under the two driving modes of fixed eccentricity driving and circular arc swing driving.The evaluation index of velocity field is established,and two meshing methods of cartesian and torus are proposed.The number of sample points and the dispersion coefficient are used to evaluate the uniformity of the trajectory and material removal.(2)Matlab software is used to carry out numerical simulation under different parameters from the two aspects of the surface uniformity of workpiece and the wear uniformity of lapping plate.And the variation rule of the movement trajectory uniformity caused by rational rotational speed ratio and irrational rotational speed ratio,fixed eccentricity driving and swing driving are analyzed.(3)A fixed eccentricity driving test platform and an irrational rotational speed ratio driving test platform are designed and built to conduct a comparative experimental study on the plane lappinging.And the efficiency of lapping and the quality of the workpiece are analyzed.Through the above simulation,it is shown that from the processing surface uniformity,the swing driving can reach the dense distribution of the abrasive trajectory and larger material removal rate faster under the same rotational speed ratio,and the abrasive trajectory density uniformity is the best under the irrational rotational speed ratio.There is no obvious circular distribution of material removal with low center under the irrational rotational speed ratio.From the lappinging plate wear,the swing driven wear trajectory area and the removal range of wear materials are larger,the overall wear trajectory is more uniform and material removal discrete coefficient are lower,and this advantage is more obvious under the irrational rotational speed ratio.Under the swing driving,the wear velocity curves of single point have no sinusoidal change,and the amplitude of single point velocity change is greater than that of fixed eccentricity driving.The influence of rotational speed ratio and driving mode on lapping efficiency and lapping surface is further verified by experimental research,and it is proved that the circular reciprocation swing driving lapping mode with irrational rotational speed ratio can obtain better lapping surface quality faster.