Research On Key Theories And Technologies Of Virtual Grinding

Grinding is an important processing technology in the machinery manufacturing industry. It is often used in the last manufacturing procedure for achieving smooth surface and precise tolerance. It is currently the most used high-performation, high precision processing technology. Grinding is superior to cutting such as turning and milling in some respects, but grinding process is much more complex than cutting process owing to its unique grinding tool. The abrasive grains on grinding wheel have no fixed shape and size, and their distribution is also irregular. Grinding wheel works in high speed. So the study on grinding mechanism and the prediction for grinding results are more difficult than some cutting process.Analysis and experimentation are traditional method in the research of grinding, but they both have some shortcomings. Analytical model is based on assumption, so its application is limitied. Experimentation is tedious. Simulation is a new research method of grinding. It makes up for the two methods’shortcomings. Virtual grinding is a more advanced simulation for grinding. The researcher can intuitively observe grinding behavior of wheel and removing process of workpiece material. It is conducive for reasearcher to make accurate evaluation for the performation of wheel and processing quality. So, its application in the research of grinding has great practical significance.Grinding mechanism and development of grinding simulation software are deeply researched by virtual grinding method and experimentation in this paper. The research tasks of the paper are as follows:(1) According to the characteristics of grinding process, Numerical simulation methods suitable for the grinding simulation are chosed. The characteristics and application scope of Finite Element Method (FEM) and Smoothed Particle Hydrodynamics (SPH) are analyzed. The feasibility of their application in the research of grinding is verified by grinding simulation examples(2) 45 steel cutting with single grain are simulated by Fluid-Solid-Interaction Method and Smoothed Particle Hydrodynamics respectively. Advantages and disadvantages of the two methods are compared. The cutting processes of single grain with different cutting parameters and orthogonal rakes are simulated by Smoothed Particle Hydrodynamics method. The mechanism of chip formation of single grain is analyzed according to the simulation results.(3) The abrasive grains have no fixed shape, size and distribution. Considering these, topography of the grinding wheel is modeled. The model is basically consistent with the actual topography of the grinding wheel. Physical process of grinding is simulated with the model. Then, the performations of the wheel and formation mechanism of workpiece surface are analyzed.(4) The processes of the rubbing and fracture of CBN abrasive are simulated by Smoothed Particle Hydrodynamics method. According to the dynamic simulation, the wear mechanism of CBN abrasive is analyzed.(5) Based on Virtual Reality Technology, virtual grinding surface system is developed by Visual C++ and OpenGL. Takes ortho-hexahedron as basic shape of abrasive grain and distribut it randomly on the grinding wheel base, then virtual grinding wheel is modeled. Interaction model of abrasive grain workpiece is also modeled. Takes surface grinding as an example, grinding processes with different machining parameters are simulated. Grinding performance of virtual grinding wheel is tested. Influencing factors of formed surface roughness were analyzed.(6) In order to verify the correctness of the single abrasive cutting simulation, the wheel model and its grinding simulation and abrasive wear simulation, scratching experiment, grinding experiment and wear experiment are made By using abrasive block of ultra-high speed vitrified bonded CBN wheel.