Research On Tool-chip Contact Characteristics Of Titanium Alloys For Quasi-intermittent Vibration Assisted Swing Cutting

Titanium alloys have excellent properties such as high temperature resistance,corrosion resistance,non-toxicity and low density,so they are widely used in aerospace,medical,automotive and other fields.However,as a difficult-to-machine material,titanium alloys face problems such as large cutting force,severe tool wear and poor machined surface quality.Quasi-intermittent vibration assisted swing cutting(QVASC)is a new machining method suitable for difficult-to-machine materials.Compared with traditional cutting methods,it has the advantages of reducing cutting force and tool wear.At this stage,the research of QVASC mainly focuses on device design,tool path planning and device cutting performance testing,etc.There are few studies on QVASC tool-chip contact characteristics.Therefore,this paper takes titanium alloy as the research object,and based on a QVASC device with a flexible mechanism as the core designed by the research group,the cutting force,chip shape and tool-chip friction characteristics in the QVASC cutting process are studied.The main contents are as follows:1)A simulation model of QVASC cutting process considering tool swing is established.Based on the quasi-intermittent cutting characteristics of QVASC,a three-dimensional simulation model of QVASC titanium alloy was established.Through this model,the influence of cutting parameters(machining method,tool rake angle,vibration frequency,feed rate,cutting speed)on the cutting force and chip shape during the cutting process is analyzed,which provides a reference for subsequent experiments.2)The friction model of QVASC tool-chip contact surface is established.Based on the shear-slip theory,the friction characteristics of the tool-chip interface are analyzed,and a tool-chip friction model is established that considers the bonding,transition and sliding regions.The model is used to analyze the changes of tool-chip contact length,shear stress and cutting force during the cutting process,and provide theoretical reference values for subsequent experiments.3)QVASC titanium alloy cutting experiment.A comparative experiment between QVASC and traditional cutting methods was carried out,taking cutting force as the research object to verify the validity of the simulation model and the advantages of QVASC machining titanium alloys;the single factor method was used to analyze the influence of cutting depth and spindle speed on cutting force,and the experimental value of cutting force was calculated.Compared with the theoretical value,the correctness of the friction model of the tool-chip contact surface is verified;the titanium alloy chip experiment is carried out to compare the change trend of chip morphology under different cutting speeds to verify the validity of the simulation model.