Study On Residual Stress Distribuation Of Single Point Incremental Forming

Single point incremental forming technology is a new type technology of sheet metal without molding.Through the simple shape of the tool,in accordance with the pre-set trajectory step by step,actually getting the demanding shape of the parts,it can save mold costs for manufacturing and maintenance,and is suitable for small batch and custom sheet metal parts processing.How to reduce the amount of springback,improve the forming accuracy and inhibit the forming defect are the problems that need to be solved urgently.The springback of the forming part is closely related to the distribution of the residual stress.Therefore,it is necessary to explore the distribution of residual stress and its influence on the forming quality,so it has important theoretical and practical engineering significance.Based on the discussion of the influence of residual stress on the properties of materials and components,the causes of residual stress are analyzed and classified.3D solid finite element model of single point incremental forming is established,which uses ABAQUS/Explicit and ABAQUS/Standard respectively to simulate the forming process and the springback process.The distribution of the residual stress along the inner surface is obtained according to the simulation results.According to the characteristics of the forming process,the formed part is divided into the bending transition area,the plane extension area and the bottom deformation area along the depth direction.The variation law of the residual stress along the wall thickness in each region is get.The influence of the tool head diameter,the layer feed rate,the spindle speed and the feed rate on the residual stress is simulated and analyzed.The relationship between the process parameters and the residual stress is established,and getting the amount of springback in the bottom of the forming part.The influence of process parameters such as tool head diameter,layer feed rate,spindle speed and feed rate on the springback of forming parts is analyzed.The relationship between residual stress distribution and springback is established.In order to improve the distribution of residual stress and reduce the amount of springback,a single point incremental forming method under isostatic pressing condition is proposed,and the forming process under this condition is simulated to obtain the effect of isostatic pressure on the residual stress distribution.The results show that when the residual tensile stress decreases the residual compressive stress increases,and the springback decreases,the accuracy of single point incremental forming can be improved.The single point incremental forming experiment is carried out,and the G code is introduced into the NC machining center.The experiment is carried out using the XRD-3000 G2 stress analyzer to measure the residual stress,getting the influence on residual stress distribution of the tool head diameter,the spindle speed,the feed rate and the spindle speed.The forming part is scanned with a high precision blue light scanner.Then the result is imported into the Geomagic Qualify software to compare with the ideal contour to obtain the amount of springback of the forming part and the low between it with the tool head diameter,the layer feed rate,the spindle speed and the feed rate,the experimental results show that the results from finite element simulation are correct.