Study On Edge Sharpness Of Carbide Alloy Guillotine Cutter

Soft-magnetic electrical steel(abbreviated as electrical steel)is a ferrosilicon alloy with low carbon content and is a very important functional material in the power industry,electronics industry and military industry.In the actual production,the burrs on the edges of the shearing section of electrical steel are normally very large.And the deterioration of section quality could directly lead to the reduction of the lamination factor for the iron core,and the hardened edge could also cause the uneven force of the material during the process of stamping foil.Therefore,with the development of the electrical steel industry,the technology demands for the cutting and processing of the metal sheet is becoming higher and higher.In this study,the cemented carbide cross-cutting scissors after mechanical grinding were taken as the test subject.Firstly,we analyzed the relationships between the surface roughness and the sharpness of the cutting edge of the carbide cross-cutting scissors,and found that the sharpness of the cutting edge was the key factor for determining the cutter sharpness.Then,through the inclined blade cutting test of electrical steel,we systematically analyzed the shearing fracture surface morphology,sheet hardening process,tissue flow,and shear force,and investigated the influence of different surface roughness on the machining effect of cutting the electrical steel.Finally,we undertook the track record of the wear patterns of the cutters with different surface roughness during the cutting process,and facilitated comparative analysis to reveal the relationships between surface roughness and wearing rules of the cutters.The detailed contents of the research are as follows:1)Mechanical grinding of cemented carbide tools.The cemented carbide tools were grinded using diamond abrasives with different diameters for grinding through the mechanical grinding process.We finally obtained four kinds of cemented carbide tools with different surface roughness.Then we used the surface roughness of cutters as measurement index,and observed the surface morphology and cutting edge radius of the blade after mechanical grinding with profiler,laser scanning confocal microscope and scanning electron microscope.The results show that the surface roughness of cutters is the key factor that determines the sharpness of the cutting edge and a sharper cutting edge can be obtained by reducing the surface roughness of the cutters.When the surface roughness of cutters is 0.010 μm,the cutting edge is straight and smooth.Meanwhile,saw tooth defects in the cutting edge are significantly reduced,and the sharpness of cutters is greatly improved.2)Cross-cutting processing of electrical steel sheet.Through inclined blade cutting experiment of electrical steel,we facilitated comparative analysis to reveal the influence rules of the surface roughness of cutters on the shearing effect of electrical steel.The results showed that the shear-band height of the shear section gradually increases with the decrease of the surface roughness of the cross-cutting scissors,as well as both the height of the fracture zone and the height of the collapse angle gradually decrease.Meanwhile,both the shear force and the degree of work hardening decrease with that change.Under a relatively smaller gap(4%),the use of cutters with a surface roughness of 0.010 μm increases the shear band height by 18%,and decreases the fracture zone and collapse angle height by 49% and40% respectively,as well as decreases the maximum shear force by 30% and the work hardening area by 29%,compared to that of cutters with a surface roughness of 0.209 μm.3)Wear test of electrical steel sheared by the cemented carbide cross-cutting scissors.Through tracking the cutting processes of electrical steel using cutters with different surface roughness,we studied and analyzed the influence rules of the surface roughness of cutters on cutter wear.The results showed that the cutters were in the initial wear stage during the first 1000 shearing tests,and while conducting the 4000 th shearing test the cutter has completely entered the period of stable wear.In addition,using the cutters with different surface roughness directly affected the wear conditions of the cutters.The heavy adhesive wear happened to the cutter with the roughness of 0.010 μm,resulting in serious initial wear of the cutter and rapid reduce of cutting edge sharpness.We found that with the increase of the surface roughness of the cutters both the wear conditions and the degree of oxidation of the cutters increases.