Research On Mechanism Of Burr Suppression And Section Quality Of In-Situ Preloading Blanking

Blanking is one of the most commonly used processes in the sheet metal forming.Because of its high processing efficiency and low production cost,it has been widely utilized in the manufacturing of automobiles,instrument,meter,and household appliances.After blanking,the edge of the sheet often has different height burr.The existence of burr will not only affect the section quality of the blanking part,but also affect the performance of the product,and it will also bring hidden danger to the production and use of the product.With the continuous improvement of section quality requirements,the realization of effective suppression of blanking burrs has attracted more and more attention from domestic and foreign scholars.This paper takes the blanking processing of plates as the research object.The main research work and contributions are as following:(1)Based on the research status at home and abroad,the in-situ preloading blanking technology is proposed to suppress the blanking burr.Analyzed the deformation process of ordinary blanking and the stress status of the blanking deformation zone,and discussed the internal relationship between crack generation and burr formation mechanism,and based on this,the process and principle of in-situ preloading suppression technology and its characteristics are explained;(2)The finite element model was established using DEFORM-2D software,and the numerical simulation of in-situ preloading blanking process was undertaken.The stress-strain distribution and material flow in the blanking process were analyzed,and it was revealed that the cross-section of in-situ preloading blanking part is composed of four areas,namely the second smooth zone,rupture zone,smooth zone and roll over.Compared with ordinary blanking,in-situ preloading blanking suppresses the formation of blanking burrs,and the quality of the obtained blanking parts is better.Based on the controlled variable method,the influential trend of relative clearance,preloading depth,preloading angle and other single factors on the smooth zone and the second smooth zone was pointed out;(3)The in-situ preloading blanking experiment of 10 steel sheets was undertaken.The simulation results were compared with the experimental results,and the cross-section morphology of the in-situ preloading blanking parts was observed with the help of a microscope.It was pointed out that although the surface of the second smooth zone was not as slick as the smooth zone,its surface roughness was obviously better than the fracture band.By comparing in-situ preloading blanking test results of three different materials and 10 steel,the influence of different materials on in-situ preloading blanking was discussed;(4)Based on the orthogonal experimental design method,the finite element simulation of a variety of process parameters combination was carried out,the primary and secondary order of each factor in the section quality control of blanking parts was defined,and combined with the specific situation,the optimization control scheme of in-situ preloading blanking process parameters was given.This research has further enriched and developed the blanking burr suppression technology,and the main conclusions obtained have certain guiding significance for the further research and application of this technology.