Simulation Of Semi-Fixed Abrasive Grinding Wheel Compacting Process And 'Trap Effect' Based On PFC2D

High accuracy and high efficiency are the permanent topics in terms of ultra-precision machining. In the existing ultra-precision machining techniques, preventing such surface defects as scratch and crack and improving finish efficiency is a pair of contradiction. The research center puts forward semi-fixed abrasive machining technology which integrates fixed abrasive machining and free abrasive machining. The key of he novel technique is to use semi-fixed grinding wheel with 'trap effect' to finish. The wheel is one of the particle granular assembles. The distinct element method(DEM) is always used for analyzing the mechanical behavior of granular assembles. Computer simulation of semi-fixed abrasive grinding wheel compacting process and 'trap effect' has been carried out based on the PFC2D(Particle Flow code in 2 Dimensions) in the paper.Distinct element model for the semi-fixed abrasive grinding wheel has been built first. Since the distinct element model accuracy depends on the model parameters, virtual direct shear test has been done to adjust the distinct element model parameters to make the virtual test results suitable for the experiment results. The penetration hardness test has been done to verify the distinct element model for the semi-fixed abrasive grinding wheel. Simulation of semi-fixed abrasive grinding wheel compacting process and 'trap effect' has been done based on the previous model. With regards to two compacting patterns of constant displacement rate and constant loading rate, under the condition of different compacting parameters(displacement rate, loading rate, abrasive grain characteristic parameters), the relationship between compacting pressure and compacting relative density has been discussed and found the simulation results have the same tendency with the test results. The preliminary simulation research on the 'trap effect' has been done. Influence of different model parameters(abrasive grain size, bond among abrasive grains, initial porosity, friction of abrasive grain) and the size of big particle upon trapping depth of big particle and its load has been discussed.The research results of the paper provide a fundamental computer simulation platform for making study on semi-fixed abrasive machining technology and mechanism.