Ultrasonic Vibration Milling And Surface Quality Control Of Cr12MoV Die Steel

Cr12MoV die steel is one of the typical hard to process materials in manufacturing industry,and it is widely used in automobile,ship,aviation,electromechanical,and so on,because of its high hardness,good wear resistance and hardenability.Therefore,how to solve the problems of low efficiency and quality control while it is milling process become particularly important,for these reason,the ultrasonic vibration cutting(UVC)technology is introduced to the milling process in this thesis,to reduce the milling force and the surface roughness,and to realize the control of milling force and surface quality by two aspects of theory and experiment research.The specific research contents and results are as follows:(1)Based on the analysis of the mechanism of vibration cutting,the change rule of the tool rake angle and the geometric relationship between the tool and the workpiece are respectively studied,and the numerical model of instantaneous UVC milling force is established by the minimum energy method.(2)Using single factor experiment method,the deference between the ordinary milling and the ultrasonic vibration milling process is studied by the milling force,surface roughness,and chip morphology difference,including the influence of ultrasonic amplitude on the milling force and surface roughness.The results suggest that UVC can reduce the milling force,improve the surface roughness,and enhance the chip breaking,the minimum value of milling force and surface roughness could be got while the ultrasonic amplitude is set in 6-7 ?m result from reducing 11.43%-25.00% of milling force and 1.04%-27.08% of the surface roughness value.(3)Based on the orthogonal experiment,the influence of milling parameters on the average peak value and average value of ultrasonic vibration milling force is studied by range and variance analysis.It is found that the milling depth has the greatest influence on the milling force,the spindle speed and the feed per tooth take the second place,and the milling width is the smallest;in addition,the mean peak value of milling force is highly consistent with the mean value,which can effectively reflect the change of milling force.(4)The prediction model of surface roughness is established by multiple linear regression method,whose highly regressive is proved by F-test,and the error between the experimental value and the predicted value is locates 1.81%-16.8%,which also shows that the model has high accuracy,confidence,and practicability.For the influence of milling parameters on surface roughness,it is found that better surface roughness could be obtain along with the smaller the feed,milling depth and milling width of each tooth,the higher the spindle speed.It is also found that the chips are tend to be broken and burned with the increasing of feed,milling depth and milling width of each tooth,and the band chips will appear with the increase of spindle speed.The results of this work have important guiding significance and value for the processing of Cr12 MoV die steel.