Design And Experimental Research Of Axial Low-frequency Vibration Tool-holder

Deep hole drilling has always been one of the difficulties in mechanical processing due to its closed or semi-closed processing environment.Axial vibration drilling technology has attracted extensive attention from many experts and scholars at home and abroad due to it can well solve many problems,such as the difficulty of interruption and removal of chip in deep hole machining,high drilling force,high cutting temperature,poor hole machining quality.Vibration drilling device is an effective way to realize axial vibration drilling.Therefore,it is of great engineering significance to design a reliable and effective vibration drilling device in actual processing.Based on the development and application of vibration drilling technology at home and abroad,this paper focuses on the following researches on axial low-frequency vibration drilling technology:First of all,by establishing the mathematical model of axial low-frequency vibration drilling,the characteristics of thickening and variable-speed cutting of axial low-frequency vibration drilling are analyzed,and the complete geometric chip breaking and incomplete geometric chip breaking under axial low-frequency vibration drilling are studied in detail.It is concluded that in the axial low-frequency vibration drilling,the reasonable matching of vibration parameters and cutting parameters can effectively control the chip shape and improve the effect of chip breaking and chip removal.Secondly,based on the axial low-frequency vibration drilling technology,a mechanical fixed-amplitude axial low-frequency vibration tool-holder is designed,and its working principle and overall installation are described in detail.On this basis,a toroidal surface model is established.The pressure angle formula of the working surface of the vibrating system is derived.The frequency of the vibrating system is analyzed and discussed.At the same time,the dynamic equation of the vibrating system is established,which lays the theoretical foundation for the design of the vibrating tool-holder.Thirdly,the paper studies the relative machinability of metal materials,especially the machinability of oxygen-free copper.The finite element software ABAQUS was used to simulate the drilling process of ordinary drilling and axial low-frequency vibration drilling for oxygen-free copper.The results show that compared with ordinary drilling,the axial force and torque of the gun drill in the axial low-frequency vibration drilling are reduced,and the cutting efficiency is improved.At the same time,the chips produced by the axial low-frequency vibration drilling are shorter,which is more conducive to chip discharge.Finally,the deep hole ordinary drilling test and the axial low-frequency vibration drilling test under the self-made vibrating tool holder were carried out on oxygen-free copper materials.The processing conditions,chip shape,and the axis of the deep hole under the two drilling methods were compared and analyzed.The results show that in the ordinary drilling of oxygen-free copper deep holes,the processing effect is best when the rotation speed n=2000r/min and the feed speed v = 18mm/min are the best.In the axial low-frequency vibration drilling processing,the processing effect is best when the rotation speed n=2000r/min,the feed speed v = 45mm/min,the amplitude A=0.05 mm,and the frequencyf= 3times/r.