Study On Preparation Process And Strengthening Mechanism Of Cutting Edge Of Inserts Based On Micro-Blasting Water Jet Technology

Micro-blasting technology has the advantages of high processing efficiency,good flexibility and high resource utilization.It can be applied to cutting edge preparation of tool,and this can not only improve the tool cutting life and processing efficiency but also reduce the processing cost.In our work three studies were carried out.According to cutting edge preparation of cutting tool through micro-blasting technology,the effects of micro-blasting process parameters on the removal and cutting edge quality of YT15 and YG6 cemented carbide inserts,Ti(C,N)cermet inserts were studied,and micro-blasting process parameters of suitable the edge radius and edge quality were obtained.The material removal and edge formation mechanism of three kinds of inserts were studied,and the corresponding empirical model and the semi-empirical theory model of edge radius were established.The influences of the cutting edge radius of inserts prepared by micro-blasting on the cutting process were studied,and the edge radius of the inserts with different materials under certain cutting parameters were optimized and obtained,and the influences of cutting edge preparation by the micro-blasting on cutting performance of cutting tool were analyzed.The effects of micro-blasting process parameters on the material removal and the edge line roughness were studied by the orthogonal experiment method,and elementary optimization of micro-blasting process parameters were conducted;and the effects of micro-blasting process parameters on the edge radius and the edge line roughness were studied by means of the full factors experiment method,and the micro-blasting process parameters obtaining the suitable edge radius and edge quality were determined.The results indicated that the greatest influence factors on the edge material removal of YT15,YG6 and cermet inserts were blasting time,abrasive mesh and blasting time,respectively.The greatest influence factors on the edge line roughness of YT15,YG6 and cermet inserts were blasting pressure,abrasive mesh and abrasive mesh,respectively.When the edge line roughness is the optimization target and taking into account the material removal,the suitable white corundum abrasive mesh for YT15 and YG6 inserts was 320 mesh,and the suitable white corundum abrasive mesh for cermet inserts was 280 mesh.The edge radius of the three kinds of inserts increased with the increase of blasting pressure and blasting time,and when the blasting pressure was 0.2 MPa and 0.25 MPa,the edge radius of inserts increased first and then decreased with the increase of abrasive proportion,when the blasting pressure was 0.3 MPa and 0.35 MPa,the edge radius of inserts increased with the increase of abrasive proportion.Based on the analysis of the edge line roughness distribution,the edge line roughness of the three kinds of inserts conformed to the gamma distribution,the probability of edge line roughness of YT15 and cermet inserts less than 0.7 ?m was 0.98 and 0.97,respectively,and the probability of edge line roughness of YG6 inserts less than 0.73?m was 0.96.And according to the edge radius and edge line roughness distribution of the micro-blasting full factors experiment,the micro-blasting process parameters preliminarily chosen based on the orthogonal experiment was reasonable.The role of water and abrasive in micro-blasting jet was studied by contrast experiment method,and the material removal mechanism and the formation process of edge shape were analyzed.And based on the BP neural network and the single particle abrasive material removal model,the empirical prediction model and Semi-empirical theory model of the edge radius of the three kinds of inserts were established.The results indicated that the pure water jet can't remove material,the material removal resulted from the abrasive erosion for the edge material,and material removal types of the three kinds of inserts included brittle removal and plastic removal.The formation of the arc-shaped edge was caused by joint action between the brittle removal of crack propagation and the plastic removal of abrasive micro-cutting.The relative error of the BP neural network model of the three kinds of inserts was less than 10%within the range of micro-blasting process,and the semi-empirical theory model of the edge radius can be used to qualitatively analyze the effects of the micro-blasting process parameters and the mechanical properties of the tool materials on edge radius.The effects of edge radius on the cutting process were studied by means of finite element simulation and single factor cutting experiment method,and the edge radius of three kinds of tools was optimized;the effects of micro-blasting edge preparation on cutting performance were studied through contrast cutting experiment.The results indicated that the cutting forces of the three kinds of inserts increased with the increase of the edge radius,and the edge radius had a greater influence on the back force,relative to the main cutting force and the feeding force.When the tool life was the optimization target and taking into account the surface roughness,the optimal edge radius of YT15,YG6 and cermet inserts were 26 ?m,36?m and 15 ?m,respectively.Compared to the inserts without cutting edge preparation,the tool life of YT15,YG6 and Cermet inserts with cutting edge preparation by the micro-blasting increased by 63%,37%and 86%,respectively.The cutting forces of YT15,YG6 and cermet inserts with cutting edge preparation by the micro-blasting were exceeded by those of inserts without cutting edge preparation with the increase of inserts wear.With the increase of cutting time,the surface roughness of YT15 and YG6 inserts with cutting edge preparation by the micro-blasting was gradually exceeded by that of inserts without cutting edge preparation,and for the cermet inserts,the surface roughness of inserts with cutting edge preparation by micro-blasting was lower than that of inserts without cutting edge preparation.The cutting edge preparation caused to the increase of saw-tooth density of the saw-tooth chip,but it didn't have much effect on the morphology of the continuous chip.The wear mechanisms of flank face of inserts were mainly diffusion wear,adhesive wear,abrasive wear and oxidation wear.