Theoretical Analysis And Experimental Research Of The Working Force In Punching And Blanking Process

Punching and blanking is a process which makes a panel separated into two parts along specific stamping contour line with tools in press.It consists of punching and blanking.Because of the convenience and the efficiency of punching and blanking,the process becomes popular in practical production.The force of punching and blanking is generally used to choose types of devices,design tools and check punch pin strength.With the rapid development of stamping technology,different kinds of stamping process,such as high-speed punching,thickness plate blanking and high strength steel plate blanking,have higher requirements about that the precision and the development process of punching and blanking force.Therefore,the research of punching and blanking force contains theoretical value in some extent and which has engineering application value in the field of high strength steel plate blanking and thick plate blanking.In this paper,the study develops theoretical analysis of punching and blanking,experimental research and numerical simulation based on stamping process.Main approaches and results of the study will be shown in the following:(1)To stamping process,the study conducts theoretical analysis of punching and blanking,establishes accurate theoretical calculation formula and provides verification for punching and blanking theory.With the use of theory of slip line,stress of sheet metal is analyzed and the maximum punching and blanking force theoretical calculation formulas are obtained by establishing force analysis models.Besides,With the use of theory of upper bound method,mechanical analysis model was established,and the calculation formula of the working force in punching and blanking process is founded.Finally,Based on the above theoretical calculation formula,the variation law of blanking force with punch pin stroke was analyzed and the effects of the process parameters such as sheet thickness and blanking clearance on the force are obtained.(2)The punching and blanking study is developed at room temperature.In the condition,experiment methods and devices are designed and the correctness of the theoretical formulas.Besides,the effectiveness factors and regulations are illustrated.By analyzing experiment results,punching and blanking force curve and maximum punching and blanking force isobtained and effectiveness laws of different process parameters like sheet thickness,punching and blanking clearance and velocity are developed.After compared with the results of experiment and theoretical results,the correctness of punching and blanking force theoretical calculation formula is verified.(3)The numerical simulation study on punching and blanking force is carried out on the basis of ANSYS/LS-DYNA software.In the study,finite element analysis model of punching and blanking is established while simulation curve and the maximum force of punching and blanking are obtained.Besides,the study shows the comprehensive analysis of numerical simulation,experimental research and theoretical calculation of blanking force.In summary,the accurately calculation formulas of the punching and blanking force are established,based on the slip line method and the upper bound method in this paper.By conducting blanking force experiment study,the accuracy of the theoretical formula is verified.The influence of different processing parameters such as sheet thickness,blanking clearance and punching speed of the blanking force are obtained.