Research On Simulation Algorithm For Grinding Of Five-axis CNC Tool Grinder

Nowadays,virtual simulation is an effective technique for NC code verification before actual CNC machining and it is also an important research content in virtual manufacturing.The technology verifies the correctness of the NC code by simulating the CNC machining process to shorten the verification cycle and reduce the verification cost.Although virtual simulation technology has been rapidly developed and widely used in numerical control machining,most of the technical research has focused on the numerical control milling simulation,while the research on numerical control grinding simulation technology is relatively rare.In this paper,the grinding simulation process of the five-axis CNC tool grinder is studied,including the five-axis linkage calculation of the CNC tool grinder,the modeling algorithm of swept volume of grinding wheel and the algorithm of grinding geometry simulation.The prototype system of the grinding simulation is developed and it can simulate the machining of the grinding process.The main research contents and research results of this paper are as follows:(1)Based on multi-body kinematics theory,the topology of the five-axis CNC tool grinder is established,and the motion simulation of the grinder is realized.The geometry model of virtual grinder is expressed by the CSG expression method.The topological connection of the components of the virtual grinder is realized based on multi-body kinematics,and the kinematics modeling of the virtual grinder is realized.The motion simulation of the grinder is realized by analyzing the motion command in the NC code and calculating the movement amount of each moving part of the virtual grinder.(2)A general model of common standard grinding wheel is established,and a general method for the modeling of swept volume of grinding wheel is proposed.Based on the commonality of common grinding wheel models,a general-purpose grinding wheel model based on parameter driving is established.By simplifying the geometric model and the initial body of the grinding wheel and based on the envelope theory,the critical point of the grinding wheel is calculated,and the grinding wheel is used to sweep the external surface through the critical point to finally obtain the complete swept volume of grinding wheel.Finally,an example is given to verify the correctness of the modeling method of grinding wheel model and swept volume of grinding wheel,which lays a foundation for the dynamic Boolean intersection calculation between the swept volume of grinding wheel and the workpiece.(3)The grinding simulation algorithm based on Dexel model is systematically studied.The discrete model expression method commonly used in geometric simulation is analyzed,and the workpiece model is expressed by Dexel discrete expression method.The independent workpiece Dexel coordinate system is established.Based on the traditional Dexel expression method,the expression method of the workpiece Dexel model is optimized.The Dexel model of the grinding wheel is calculated by determining the interference area between the workpiece and the grinding wheel.Finally,the Boolean difference operation between the two models is realized by linearly comparing the Dexel model structural elements between the workpiece and the swept volume of grinding wheel.(4)The grinding simulation system of the five-axis CNC tool grinder is developed and the verification of the grinding simulation example is completed.The overall design and detailed design of the grinding simulation system of the five-axis CNC tool grinder is completed,and the simulation system that meets the grinding simulation requirements is developed.Finally,the simulation result of the grinding simulation of workpiece is obtained through a grinding machining example in the simulation system.