Research On The Drilling Performance And Tool Wear Characteristics Of Difficult-to-cut Materials

Due to the universality and convenience of hole processing,it has become one of the most commonly used processing techniques in metal processing.However,when machining difficult-to-cut materials such as titanium alloys,dry cutting without the use of cutting fluid often has problems such as high drilling force,difficulty in chip evacuation,and severe tool wear.The pouring cutting method is not friendly to the environment and the operator,It will cause a certain degree of pollution.Based on this background,the hole processing is restricted.Therefore,this article introduces vibration drilling technology and minimum quantity lubrication cutting technology into the drilling process of difficult-to-cut materials.By studying the chip shape,drilling force,bit wear and machining accuracy during drilling to analyze the drilling performance and influencing factors of difficult-to-machine materials.This article first analyzes the angle of the twist drill,and then establishes a mathematical model of the drilling force for a main cutting edge of the twist drill based on the actual working angle of the drill bit,the bevel cutting model,and the distribution and composition of the drilling force of the twist drill.And based on the distribution ratio of drilling force,calculate the drilling force during vibration drilling.Afterwards,the vibration drilling test of TC4 titanium alloy was carried out.The analysis of the test results found that the maximum error between the thrust force test value and the theoretical value was 16.46%;The influence of various factors on drilling force is as follows:feed has the largest influence,amplitude has the second influence,and drilling speed has the smallest influence.Then,based on the orthogonal test results,the least square method is used to establish the regression model of the drilling force,which can realize the accurate prediction of the drilling force.Studying the wear characteristics of the drill bit is of great significance in choosing cutting conditions reasonably,improving the machining quality of the workpiece and how to use the tool correctly.In this paper,the wear form and the wear process of the tool are analyzed respectively,and the effect of drill bit wear on TC4 titanium alloy when drilling under different drilling conditions(ie,workpiece material,tool material,cutting amount and amplitude)is analyzed through experiments.The corresponding relationship between drilling force and bit wear is also verified through experiments,that is,the amount of bit wear will have a direct impact on the thrust force,and the change of thrust force can also indirectly show the amount of bit wear.Minimum quantity lubrication cutting technology has unique advantages in lubricating penetration,cooling,and reducing cutting force.This technology is an effective alternative to traditional casting cutting.This article analyzes and studies the lubrication mechanism of minimum quantity lubrication technology from the lubrication penetration mechanism,cooling mechanism and cutting mechanism,and combines vibration drilling technology with minimum quantity lubrication technology to analyze the effect of vibration drilling on the minimum quantity lubrication,and finds that vibration drilling can effectively improve the lubrication effect of MQL with its unique process advantages.Through the experiment,the influence of different lubrication conditions on the wear of the drill bit when drilling TC4 titanium alloy was studied.It can be known that with the increase of the cutting fluid flow and pressure,the amount of drill bit wear can be reduced.Comparing the drill life tests under different machining methods,it can be found that both vibratory drilling and MQL technology can significantly increase the drill life.