| In recent years,with the development of science and technology,industrial production has continued to aim for higher levels of precision,automation and intelligence.Therefore,the requirement for the processing accuracy of parts is getting higher and higher.Because 304 stainless steel has the cutting characteristics of large cutting force,large cutting deformation and easy tool wear.So the traditional drilling processing cannot meet the actual processing requirements.Ultrasonic vibration assisted drilling(UVAD)has the characteristics of intermittent cutting,which makes it possible for UVAD to produce processing effects that are difficult to compare with ordinary drilling.In this thesis,the ultrasonic vibration assisted drilling technology is studied for 304 stainless steel materials.The research includes three aspects:theoretical analysis,simulation analysis and experimental analysis.The main contents of the paper are as follows:(1)Refer to the relevant literature,and summarize the research background,significance and research status of ultrasonic vibration assisted drilling technology at home and abroad.Then the main research content of this thesis is determined.(2)The processing characteristics of ultrasonic vibration assisted drilling are analyzed and studied.The trajectory of the point farthest from the drill axis on the main cutting edge in ultrasonic vibration assisted drilling is determined.The restriction conditions of variable thickness cutting and interrupted cutting in ultrasonic vibration assisted drilling technology are defined.(3)The axial force of ultrasonic vibration drilling is analyzed.Firstly,the axial force of ultrasonic vibration drilling is modeled,and the related parameters of twist drill with diameter of 5 mm and 304 stainless steel material are calculated.Then,in order to judge the influence of ultrasonic vibration drilling on the axial force,the axial force of ordinary drilling is modeled and calculated.Finally,the influence of ultrasonic vibration drilling on the axial force is determined by analysis and comparison.(4)The finite element software is used to simulate the common drilling and the ultrasonic vibration drilling.Through the analysis and comparison of the simulation results,the influence of ultrasonic vibration drilling on the axial force is verified,and the influence of ultrasonic vibration drilling on the burr is determined.(5)The single-factor experiment of ultrasonic vibration drilling is carried out to study the effects of three factors:spindle speed,feed rate and ultrasonic amplitude on ordinary drilling and ultrasonic vibration drilling.Then the orthogonal experiment of ultrasonic vibration drilling is carried out.The optimum horizontal combination of processing parameters with minimum axial force in drilling process is determined. |
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