Research On Evaluation Method About Trajectory Uniformity And Simulation Method Of Workpiece Surface Shape Evolution In Lapping

The purpose of plane grinding is to improve the flatness and reduce the roughness.In this paper,the research on the formation process of plane grinding surface accuracy is carried out from the two aspects of plane grinding trajectory uniformity and surface accuracy evolution.In order to lay the foundation for the prediction of the workpiece surface shape during the processing of the workpiece,the research work of the thesis is as follows:(1)Introduced the mechanical and control system structure of the plane grinding prototype used in the experiment;aiming at the abnormal vibration of the plane grinding prototype when processing the workpiece,the grinding prototype was improved by reducing the weight of some parts,and the after grinding prototype was analyzed Carry out the modal and establish the kinematics model of the machine tool.(2)A method for evaluating the uniformity of grinding trajectories based on ADAMS simulation data and statistical principles is given.According to the structure size and motion function of the machine tool,the trajectory simulation model of ADAMS was established to obtain the grinding trajectory of the abrasive particles on the workpiece under different parameter conditions.By discretizing the abrasive trajectory of the abrasive particles and gridding the workpiece surface,it was selected by judgment The discrete points of the traj ectory on the workpiece grid unit,the frequency of the discrete points of the trajectory of the workpiece grid unit is counted,the standard deviation of the trajectory frequency of the entire workpiece surface unit is calculated,and the ratio of the overall standard deviation to the arithmetic mean is the coefficient of variation evaluation Trajectory uniformity.By chatnging the speed ratio of the grinding disc to the workpiece suction cup in the built ADAMS,and the eccentricity parameter of the workpiece on the workpiece suction cup,the coefficient of variation on calculated and the rule of the influence of the speed ratio and the eccentricity on the trajectory uniformity is determined.Through orthogonal simultion method,an optimal set of patrameter combinations and a better set of parameter combinations are selected.(3)Drawing on the Archard friction and wear model,a simulation method for the evolution of the surface shape of a flat-grinding workpiece using ABAQUS software is given.Double-integrate the stress and speed of the contact point to establish a grinding Archard model that meets the machine tool’s structural size and motion function and the physical conditions of the grinding disc and the workpiece.For the problem that the stress curve of the contact point between the workpiece and the grinding disc is more complicated,the Discrete calculation of the stress curve,after calculating the grinding amount of each step,the grinding amount is used as a factor that affects the stress value,and the finite element modeling is used to calculate and analyze the stress of the contact surface between the grinding disk and the workpiece.Distribution,so as to get the surface shape of the workpiece during processing.Under the condition that the linkage mode of the grinding disc and the suction cup is a circular cycloid,by changing the rotation speed ratio of the grinding disc and the suction cup and the eccentricity parameter of the workpiece and the suction cup,the distribution of the grinding amount on the surface of the workpiece is obtained,and the whole workpiece is evaluated by the coefficient of variation of the grinding amount Grinding amount and obtain the influence rule of the speed ratio and eccentricity on the overall grinding amount of the workpiece surface;use orthogonal parameters to simulate the evolution of the workpiece surface shape,and select the optimal set of parameters according to the coefficient of variation of the grinding amount.(4)A group of optimal parameter combinations based on the uniformity evaluation method was used to perform the grinding process experiment and compared with the non-optimal parameter combination grinding effect,and the correctness of the screening method using the coefficient of variation as the planar grinding trajectory was verified.A set of optimal parameter combinations selected based on the grinding evolution simulation method was used to perform the grinding process experiment and compared with the non-optimal parameter combination grinding effect,which verified the feasibility of the planar grinding evolution simulation method given in this paper.