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Simulation And Experimental Study On The Influence Of Biglide Parallel Grinder Initial Positioning On Grinding Helical Drill Point

Posted on:2020-12-12Degree:MasterType:Thesis
Country:ChinaCandidate:Z Y DengFull Text:PDF
GTID:2481306353962899Subject:Mechanical Manufacturing and Automation
Abstract/Summary:PDF Full Text Request
The structure of the flank surface of the twist drill is the key to affect the drilling performance,and the performance of the drill with different geometrical structure of the flank surface is different in the aspects of centering,forming process,cutting force and service life.The common grinding methods for ordinary twist drill are grinding method for plane surface,grinding method for cylindrical surface,grinding method for conical surface,grinding method for hyperboloid twist drill and grinding method for helical surface.Compared with the common drill point,the helical drill point has better automatic centering performance in the drilling process,improves the precision of drilling,reduces the drilling force,and prolongs the service life of the drill.For the twist drill,the geometry of the drill point is the key to affect the drilling performance.Based on a biglide parallel CNC grinder,this paper studies the law of the geometric structure of helical drill point by different positioning conditions of grinding wheel and drill from three aspects of theory,simulation and experiment.Firstly,the theory of grinding helical drill point based on biglide parallel grinder is studied in this paper.Some of the main work contents of this paper are as follows:The kinematics equation of two parallel mechanism for planar motion is deduced,the feasible conditions for the motion interference of grinding wheel to drill in the process of grinding are analyzed,and the spatial surface equation of core flank surface,outboard flank surface and rank face of the helical drill point are established.On the basis of each spatial surface equation,the parameter expressions of the helical drill point are deduced by using the semi-point angle,the chisel edge angle,the front angle of chisel edge and the relief angle of outer turning point.Secondly,this paper simulates and analyzes the factors influencing the semi-point angle,the chisel edge angle,the front angle of chisel edge and the relief angle of outer turning point,and puts forward the calculation method of the positive and negative solution model of the geometric structure angle of the helical drill point.Numerical simulation of several geometrical structural angles of helical drill point under different parameter conditions is carried out,and the influence of single factor variables on the geometrical structure of helical drill point under certain conditions is numerically simulated.Finally,under the different positioning parameters of grinding wheel and drill,the experiment of grinding helical drill point is carried out,and the measured value of geometric structure angle of helical drill point is compared with the theoretical value obtained by simulation.The results show that the geometrical structure of the helical drill point under this machine tool is uniquely determined by the end motion characteristics of the machine tool,the mounting attitude of the grinding wheel,the positioning of the grinding wheel and drill relative to the grinding wheel.When the longitudinal position of the grinding wheel changes,the front angle of chisel edge and the relief angle of outer turning point can change continuously in a certain range,and the chisel edge angle can change linearly in a large range when the drill changes relative position to grinding wheel in the initial moment.By changing the positioning parameters of the grinding wheel and the drill at the initial moment under this biglide parallel grinder,the demand of grinding helical drill point with different structure can be satisfied.
Keywords/Search Tags:biglide parallel grinder, helical drill point, position parameters, numerical simulation, grinding experiment
PDF Full Text Request
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