Research On The Multi-Stage Path Of AA5052 Sheet For Single Point Incremental Forming

Incremental Sheet Forming(ISF)is a flexible,mold-free forming process that provides an economical,time-saving solution for rapid prototyping and small batch production and it has great application potential in the fields of trial production,medical restorations and aviation industry.Multi-stage forming is suitable for forming parts with large forming angle and complex profile,which compensates for the shortcomings of single-stage forming.As a lightweight and cold-worked material,AA5052 is widely used in the transportation vehicles and other fields.In this paper,the multi-stage path of AA5052 sheet for single point incremental forming was studied.Firstly,the flow law of material in multi-stage incremental forming was explored.It is concluded that the material in the subsequent stages has obvious radial flow,so the metal flow can be controlled by rationally designing the forming path to effectively improve the forming quality;The influence of the moving form of the forming tool on the flow characteristics of material was studied,and the formation of the hemispherical part illustrated that the bottom-to-up movement mode of the forming tool is beneficial to improve the excessive thinning of the sheet metal.And then,taking a cone with 60° angle as the target part,a series of multi-stage single-point incremental forming scheme were developed,with n and(35)? as the independent variables.The simulation results show that: when(35)? is constant,the minimum thickness of the workpiece increases with the increase of n value,and the wall thickness distribution is more uniform,but the amount of sinking at the bottom of the workpiece also increases;When n is certain,the influence of(35)? on the wall thickness distribution is not obvious,but it is clear that(35)? is proportional to the sinking of the workpiece.Experiments were carried out according to the above scheme,and the results were consistent with the simulation,which proved the correctness of the finite element model.Finally,a series of multi-stage forming path schemes were designed with the part diameter,forming angle and forming depth as the variables.The straight-walled cylindrical parts were taken as an example to compare and analyze the relative forming performance of each forming scheme.The test results show that the straight wall cylinder can be successfully processed by gradually increasing the diameter of the part and the forming angle.This result can provides guidance for multi-stage incremental forming pass planning,reducing the blindness of process planning.