Research On Coated Cutting Tool Processing Using Micro Abrasive Water Jet

Due to the low stability and low impact resistance,sharp cutting edge was generally considered to be disadvantageous for high performance cutting processes.In order to enhance tool-performance,cutting edge preparation has become increasingly important.The preparation of the cutting tool edge aims to stabilize the cutting edge,eliminate the chipping,improve the tool surface roughness and chip flow.This also leads to increase tool life and cutting process reliability,obtain a better workpiece quality.To achieve special geometries for the cutting tool,different manufacturing technologies can be applied,such as brushing,gringing,abrasive blasting,magnet finishing.A new method for cutting tool edge preparation using micro abrasive water jet was proposed.It not only create a new field of cutting tool edge preparation technology,but also expand the application range of micro abrasive water jet.Taking carbide thread chaser as the research object,simulation of screw machining was carried out using the finite element analysis software ABAQUS.The influence of the radius of cutting edge roundness on cutting force and cutting temperature was analyzed.The simulation results showed that tool cutting temperature distribution mainly concentrated in the nose of the tool.When the radius of cutting edge roundness increase,the cutting force first increased and then decreased,nevertheless the cutting temperature first decreased and then increased.When the radius of cutting edge roundness was around 0.02 mm,the cutting temperature was in the lowest level.The simulation results were verified by experiments.Experimental measured results and the prediction results of simulation model had good consistency.Using a mathematical method description of cutting tool geometries,an approximation of general round edges by applying several chamfers has been proposed and a geometric model for designing these special tool has been suggested.By means of the theoretical research,a model for cutting tool preparation process with micro abrasive water jet was established.Based on the orthogonal experimental design,the test for preparation of cemented carbide cutting tools were conducted.The temperature of preparation tool surface in the process,cutting tool edge roundness radius and micro-structures,the micro-structure and metallographic structure of cutting tool surface were studied.The result indicates that the temperature of preparation tool surface in the process was 25.2?.The burning of cutting tool surface was avoided effectively.The average of the tool edge roundness radius and surface roughness were 21.54?m and 0.787?m respectively.The metallographic structure of cutting tool surface was not changed.Meanwhile,using the datas of orthogonal test,a back propagation neural network model for the radius of cutting edge roundness and a regression model for surface roughness of tool preparation with micro abrasive water jet were established.The maximum relative predictive error of neural network model and regression model was 4.60% and 7.55%.In order to study the influence of tool substrate pretreatment on the binding strength of coated tool,the coating experiment of carbide thread chaser was carried out.Using the MFT-4000 multi-function material surface performance tester and surface roughometer,the bond strength and roughness of coated tool were measured.This experiment results showed that after coating the surface roughness value of cemented carbide tool was decreased,with the increase in the surface roughness values of tool substrate,binding strength of coated tool increased and then decreased,and the ideal substrate surface roughness was approximate 0.8?m.