Experimental And Simulation Research On Surface Skid Line Of Stamping Parts

With the advancement of times,people's aesthetic ideas are constantly improving and changing,and automobile product design has been developing and changing to a high level.Though the evolution of automobile modeling design,we can find that there is an obvious trend in automobile design language,that is the automobile appearance is becoming more and more angular.However,it greatly increases the difficulty of the production of automobile body panel.In the automotive industry,automobile body panel is often referred to as class A surface.Such surface requires no serious reflection problems under light condition after painting.The common surface defects of automobile A class surface are die indentation,collapse,distortion,impact line and skid line,etc.The skid line is defined as a visible band on the non-contact side of the sheet metal panel.In the stamping process,skid lines can occur when sheet metal moves over radii with bending,unbending and stretching.Skid line has a strong impact on the surface quality of automobile body panel.This kind of defect on the surface greatly increases period and cost at the mold development stage.Therefore,the risk of skid lines before releasing the draw die development has to be assessed in the stage of stamping CAE,so as to prevent a lot of changes to the die and process in the stamping production.However,it is still a challenge to use computer simulation to predict and display the actual observable sliding line and to quantitatively evaluate the severity of the sliding line.Therefore,this paper mainly studies the rules for different parameters on the skid line,and combines experiment with simulation to improve the predictive accuracy of skid line.The main research contents of this paper are as follows:?1?In this paper,a kind of lightweight material aluminum alloy AL6061-T6 is adopted as the research object,and skid line problem in stamping process is studied.Firstly,study the basic mechanical properties of the material and provide necessary data for simulation analysis.Uniaxial tensile test is carried out according to the requirements of national standards.The test consists of two parts:one is to obtain the force-deformation curve of the material,and then obtain the true stress-true plastic strain curve through calculation.The second is measuring the Lankford coefficient of the material.The value respectively:₀r=0.762?r₄₅=0.493 and r₉₀=0.795,and indicates that the material has obvious anisotropy.So the three-parameter Barlat material model is selected.?2?A set of U-shaped mold is designed to generate skid line according to the condition of skid line.The experimental research are completed with different parameters such as die radii,drawbead height and rolling direction.Then,according to the visual observation and experimental measuring the surface roughness at the position of skid line,found that the more serious the skid line,the larger the surface roughness value.Based on this rule,the value of surface roughness is proposed as a parameter to characterize the severity of skid lines.?3?The finite element simulation model is established based on AutoForm software,and the results of simulation and experiment are compared to further reveal the influencing law of different process parameters on the skid line.At the position of the skid line on the experimental sample,the method of detecting the skid line using the simulation post-processing technology is discussed.It is observed that the severity of the skid line is related to the contact pressure and unbending strain in the software,which can provide reference for solving the skid line problem in actual production.