Research On Single Point Incremental Forming Characteristics Of Variable Pressure Support

Single-point incremental forming is a flexible and progressive thin-walled plastic forming technology,which has the advantages of a wide range of applications,high flexibility in process implementation,energy saving and material saving,etc.It has a wide application prospect in forming thin-walled complex parts.Based on the idea of "layered manufacturing",this paper introduces variable pressure support into single-point incremental forming and investigates the changes of forming force,equivalent force,surface residual stress,and wall thickness of formed parts under different support conditions through a combination of theoretical analysis,simulation,and experimental verification.This method provides theoretical support for the engineering application of single-point incremental forming technology.From the perspective of shear deformation,the stress characteristics of the contact area between the tool head and the sheet under hydraulic support conditions are studied,and the stress state of the microelements in the contact area is obtained.The finite element model of single-point incremental forming with variable pressure support based on ABAQUS is established,and the simulation of the forming process and rebound state of single-poin t incremental forming with variable pressure support is carried out.By changing the hydraulic support load during the forming process,the effects of different hydraulic support methods on the stress-strain distribution,residual stress,and material thinning rate of the formed part are studied,and the variation law of the unit wall thickness with time is obtained.A variable pressure strategy to improve excessive wall thickness thinning was developed.The single-point incremental experimental platform of hydraulic support was constructed,and the forming force,surface residual stress,and wall thickness thinning rate after unloading and rebounding of the fabricated part,as well as the influence law of variable pressure support on the forming characteristics of the fabricated part under different hydraulic support loads,were obtained through systematic experiments,and the accuracy of the finite element model was verified through the comparison and analysis of simulation and experimental measurement results.A comprehensive analysis of the improvement of defects such as uneven distribution of residual stresses and excessive thinning of the part by variable pressure support was carried out.Taguchi orthogonal experiments are used to study the influence of radial residual compressive stress and thinning rate as well as different process parameters on the forming quality of the part under the coupling conditions of multiple forming parameters.The optimal combination of process parameters to improve the residual compressive stress and reduce the thinning rate was obtained under the premise of ensuring stable forming quality,which provides a reference basis for practical engineering applications.