Forming Method And Experiment Research Of Wire Cutting Of Twist Drill Flank Surface

After being drilled,there exists a wear and tear of the drilling bit,so it needs to be regrinding to be able to continue to use.At present,the grinding wheel sharpening is a more commonly method in sharpening.However,there are many problems in the grinding wheel sharpening method,such as complex forming device structure,hard working of high hardness material.In this regard,this paper introduces a new forming method,that is,line cutting method for cutting edge of twist drill.Then,taking as electric spark line cutting machine tool as an object,an experimental investigation is made,and its feasibility is verified.Furthermore,the experimental data are analyzed and optimized to obtain reasonable processing parameters.The primary coverage of this research lists:?1?The basic composition,structural parameters and geometric angles of the twist drill are analyzed.Several common forming methods of twist drill flank surface,such as cone surface method,plane method,common spiral surface method,variable guide spiral surface method,spiral cone surface method and cylindrical surface method,are studied.And their respective forming principles are analyzed.Based on the above forming methods,this paper studies the forming principle of wire cutting forming,establishes its mathematical model,determines the mathematical equation of the front angle of the bit and the oblique angle of the cross blade,and establishes the parameterized modeling of the structure of the twist drill.?2?The machining principle of the wire cutting technology,the taper machining function and the technological parameters and evaluation indexes of the test are studied.A test platform is set up,and a taper forming device,special for the test of this subject,is designed and developed.The test scheme is formulated and the single factor testing method,the orthogonal experiment method and the grey relational grade are discussed respectively.And the track parameters of the experiment were planned and the machine parameters were set.?3?The single factor experimental method is being used to make a forming test,and the influence of four technological parameters?pulse width,pulse gap,peak current and preset feed speed?on the two evaluation indexes of material removal rate and surface roughness is analyzed,and the influence trend map is drawn.The orthogonal table is designed to determine the experimental factors and levels and to make the orthogonal test scheme.Combined with the orthogonal test design and range analysis,the order of the influence of four electrical parameters on the two evaluation indexes is determined.The experiment shows that the order of the material removal rate is:the preset feed speed D>pulse width A>pulse gap B>peak current C,and the sequence of surface roughness:the preset feed speed D>pulse width A>pulse gap B>peak current C.?4?Using the grey relational analysis and dimensional normalization method,to process and optimize the test results,and obtain the optimal combination of process parameters.The optimization results show that the optimal parameter combination is A₄B₃C₁D_4.In other words,the pulse width is 20?s,the pulse gap is 9?s,the peak current is 1,the preset feed speed is60Hz.Through the research of this subject,a new method of line cutting method for cutting edge of twist drill is obtained,and the related electrical parameters that affect the line cutting of the blade surface of the twist drill are obtained through the forming test.In addition,it can be seen from the measurement results of the geometric parameters of the cutting edge of twist drill that the outer edge angle and the oblique angle of the twist drill are within the allowable error range of the theoretical value,and once again the feasibility of the wire cutting method is verified,which provides a certain theoretical and practical basis for the follow-up study.