Research On Polishing Mechanism And Process Planning Of Automobile Die

The automobile dies play an important role in the manufacturing industry.It is an inevitable trend to use industrial robots or CNC machines to polish automobile dies instead of manual polishing in the future.Therefore,based on the industrial hybrid robot developed by Tianjin University,the polishing of complex surfaces is analyzed in this paper.Firstly,the contact model between polishing tool and spherical surface was established based on ABAQUS,and the pressure distribution in the contact area was obtained.Based on the geometric relationship during polishing,the velocity distribution in the contact area was obtained.According to the Preston equation,the distribution of material removal function was obtained.Then,the influence factors of contact pressure were analyzed.The analysis results show that both the polishing force and the offset distance of the polishing tool have influence on the position of the actual polishing point.Through a large number of simulation experiments,the offset distance of the actual polishing point under different polishing force and offset distance was obtained,providing a simulation data basis for the subsequent trajectory planning.Secondly,in the variable curvature surface,the change of surface has a great influence on the selection of polishing parameters.In this paper,the contact model between polishing tool and variable curvature surface was established,and the influence of curvature changing rate on contact pressure and material removal was analyzed.The results show that the sharper curvature changes,the smaller the contact width,the greater the contact pressure and material removal.Different curvature change rates have no effect on peak coordinates of material removal.When dealing with the contact problem of variable curvature surfaces,the contact area is usually equivalent to a spherical surface and calculated according to the radius of the spherical surface.In this paper,the material removal under the above two conditions is compared.The results show that the treatment as equivalent spherical surface will reduce the material removal,increase the contact area,and make the material removal distribution become uniform,which is different from the actual material removal distribution.Finally,the single-point polishing experiments were carried out using the self-built polishing platform with the mold steel as the polishing material.The contour curve of the actual material removal after polishing was compared with the theoretical contour curve,and the material removal equation coefficients under different sandpapers were determined.The accuracy of the finite element model was verified,and the influence of polishing parameters on the material removal rate and surface roughness was analyzed.It was concluded that the automatic polishing of this robot can quickly realize the material removal and obtain good surface quality.