Study On Process And Numerical Simulation In Sheet Incrementally Pressing Forming

Incrementally pressing forming is a kind of sheet metal incremental forming technology,on the basis of ordinary continuous incremental sheet forming,draw lessons from the movement characteristics of incremental sheet forming by hammering.The forming technology have advantage of ordinary continuous incremental sheet forming and incremental sheet forming by hammering.Therefore,in the process of sheet metal forming parts with the small circumferential distortion,forming performance is better,and it is suitable for the processing of perforated plate,industrial application value is higher.In this paper,a new method of forming incrementally pressing forming technology is presented,and the feasibility of this method is verified by experiments.This new method does not need to change the forming equipment,only need to change the tool head motion trajectory program,the method is simple and easy to operate.In combination with the experiments and numerical simulation,the forming technology of incrementally pressing forming is studied,the deformation characteristics and basic problems of the new method are studied.The results of numerical simulation in incrementally pressing forming show that the incrementally pressing forming mechanism of deformation is same as ordinary incremental forming,it can be divided into four areas: bending area,non-uniform tensile area,uniform tensile area and the local forming area.In uniform tensile area,The variation of sheet thickness in incrementally pressing forming process follows the sine law,the average thickness value is higher than the ordinary incremental forming;The strain state is the plane strain state,the major principal strain decrease obviously when compared with the ordinary incremental forming;Z-axial direction force in incrementally pressing forming is less than ordinary incremental forming.The influence of process parameters on the formability of sheet metal forming is studied by experiments,The results show that the formability of incrementally pressing forming is higher than ordinary incremental forming.The ability to influence formability in incrementally pressing forming is tool diameter > Z-axis layer feed > feed speed > amplitude > wavelength.The incrementally pressing forming which need to be improved is the long processing time and low forming precision,it can reduce processing time by increasing the feed speed,Z-axis layer feeding and wavelength Z axis layer,or decreasing amplitude.The forming precision of incrementally pressing forming can be improved by reducing the Z-axis layer feed,wavelength and amplitude values of process parameters.By using the surface roughness test,micro hardness test and tensile experiments to analyze the influence on the surface quality and mechanical performance of the sample by incrementally pressing forming in different parameters.The results show that the wavelength have great influence on the surface quality.The surface roughness value will increase with the wavelength increase.Amplitude have little influence on surface quality.Hardness and strength will be increased with the increase of wavelength and amplitude value,the plasticity will decrease.The new method of forming incrementally pressing forming technology in the paper is worthy to be popularized and applied in industrial application.Whether it is used in the process of perforated plate,or in combination with conventional incremental forming process for complex parts,It is a new method for flexible sheet metal processing.