Study On The Processing Process Of Plastic Shearing By Disc Cutter And Reverse Compression Separation For Sheet Metal

Sheet metal shearing is an important part of plastic cold processing of metal products,and its products involve IT,electrical and telecommunications,office machines,automobiles,hardware products and other industries.As a supporting technology for sheet metal processing,sheet metal shear processing promotes the development of cold processing technology for the entire metal product.Based on the concept of flexible supply and low-carbon economic development,continuous improvement of material utilization and processing accuracy is required to meet the needs of multiple varieties,small batch production,and high-precision processing modes of metal products.New technologies for precision cutting of metal sheets are proposed.Higher requirements.Aiming at the longitudinal slitting process of the disc shear,this paper proposes to control the material stress and strain state of the metal sheet during the slitting process,and decompose the slitting process into two stages of plastic shearing and compression separation to achieve the metal sheet breaking,and obtain a better shape.The section morphology,the section of the sheet metal without burrs.In-depth research has been conducted on the key technical issues of the burr-free precision slitting process of plastic shear-reverse compression separation.The specific work mainly includes the following four aspects:Firstly,for different process parameters(lateral clearance c,radial clearance δ,thickness t,sheet material),systematic experiments have been conducted to study the feasibility of the plastic shear-compression separation and shearing process and the law of section morphology.The shear section of the sheet has double rollover,double shear zone,and fracture zone.The section is smooth and flat,and the shape accuracy and dimensional accuracy of the section are improved.The radial clearance is the key process parameter of plastic shear-reverse compression separation.The lateral clearance has a certain influence on the profile of the sheet.When the lateral clearance is 0,the quality of the cross-section of the plate is the best;Sheet metal of different materials and thicknesses can be sheared and separated by plastic shear-reverse compression separation,and good processing results can be obtained;for galvanized sheet,lateral clearance of 0～0.02mm(0%-1.25%t),radial clearance of 0.48～0.64mm(30%t-40%t)has the best processing effect.Based on the processing principle of plastic shear-reverse compression separation,two finite element simulation models of associated processing are established.Through the comparison between the experimental and simulational morphological characteristics of sheet metal,the correctness of the simulation of plastic shear-reverse compression separation is verified.Secondly,combined with experimental research and simulation analysis,the structure flow and stress state of the shear deformation zone in the plastic shear-reverse compression separation process of the metal sheet,found that the closer to the side and cutting edge of the disc cutter,the greater the stress and strain,both the shear band and the residual layer show obvious fibrosis;as the lateral clearance increases,the height and width of the rollover increase;as the radial clearance decreases,the maximum shearing depth of the disc cutter increases,and the deformation and range of the tissue in the shear zone gradually increase;the galvanized layer and insulating coating on the rollover surface of the sheet are observed,and it is found that the coating in the rollover area is deformed by tension and bending.The damage is relatively high,and the part near the shear zone is more serious.Brittle coatings are more prone to damage than plastic coatings.Thirdly,the research on the correlation between plastic shear and reverse compression shows that when the breaking roller is rolled,the rollover surface is squeezed and locally flattened,and the shear area after plastic shear hardening forms a "square edge",and cut the remaining layer of sheet metal.Combining experimental research and simulation analysis of sheet metal plastic shear-reverse compression separation process,the surface material structure flow and stress state of the sheet after reverse compression separating,the geometric model of the reverse compression separating is established,and the "丿-shaped cutting edge" rolling shear backlash formula is proposed.As the radial clearance increases,the thickness of the residual layer increases,the tensile and rotation changes of the metallographic structure can be reduced,and the depth of work hardening can be reduced.Radial clearance is a key process parameter that determines reverse compression separation;Sheet compression separation is the result of tearing crack propagation,and finally a fracture zone is formed.Finally,by tracking the wear of the disc cutter in plastic shear-reverse compression separation process of the metal sheet,it is found that the wear of the disc cutter can be divided into three stages:the initial stage of severe wear,the period of stable wear,and the end of rapid wear;There is a linear correspondence between the long and short axis of the blade edge profile of the belt and the cutter side wear area.As the shearing distance increases,the width of the wear zone first increases rapidly and then steadily increases,and the difference with the side edge width gradually decreases;The wear mechanism of the Disc cutter includes the loss of cobalt oxide at room temperature,the alternating stress accelerates the loss of cobalt oxide,abrasive wear and binder phase wear.Formed porous and softened sides,more uniform wear bands,flaky shedding,scratches and other wear morphologies.Combined with the shearing wear simulation of disc cutter,the influence mechanism of process parameters on wear is obtained.The disc cutter wear model was established.The study found that increasing the lateral clearance and radial clearance can significantly reduce the disc cutter wear of the plastic shear-compression separation.