Research And Control Realization Of V-Shape Free Bending Forming Technology

CNC bending machine is a very important mechanical processing equipment,which plays a very important role in sheet metal forming and processing.It has a very wide range of applications in traditional mechanical processing industries such as automobiles,ships,aerospace,electrical instruments and so on.Compared with foreign countries,the domestic CNC bending machine started late.Although it is developing rapidly at present,the middle and high-end market is still monopolized by foreign countries.As an inevitable defect in bending process,springback seriously restricts the accuracy and quality of bending parts.This paper mainly studies springback in bending process,and combines with the NC bending system independently developed by the research institute to compensate the bending parts.The main work is divided into the following aspects:?1?Analyzing the forming process of V-shaped free bending,deducing the formulas of thinning coefficient and bending force,and establishing the downward pressure model of slider before unloading.?2?Based on ABAQUS finite element software platform,the process of V-shaped free bending forming and springback was simulated by finite element method.The effects of sheet thickness,material performance parameters?elastic modulus?and die geometry parameters?upper die fillet radius,lower die fillet radius and lower die opening width?on springback were analyzed.?3?Orthogonal experiment was designed,the springback of sheet metal was taken as the test index,and the thickness of sheet metal,the elastic modulus of sheet metal,the radius of upper die fillet and the width of lower die opening were taken as the influence factors.The orthogonal table—L₂₅?5 ⁴?was selected and the orthogonal test results were analyzed.Based on the orthogonal experiment,the prediction model of springback of sheet metal with the Inverse Multi-Quadric function was established.?4?In order to verify the accuracy of springback prediction model,on the one hand,the simulation is carried out in ABAQUS finite element analysis software,on the other hand,the actual processing verification is carried out in Anhui Donghai Machine Tool Manufacturing Co.,Ltd.Based on the VS2010 platform,a human-computer interface for springback prediction of V-shaped free bending is designed,which can directly calculate springback prediction value according to input parameters.Combined with the empirical formula of springback compensation,the springback is compensated.