Toolpath Planning and Generation for Multi-Stage Incremental Forming Based on Stretching Angle.

Hu Zhu,Dongwon Jung,Guixi Cheng

doi:10.3390/ma14174818

Abstract

To solve the problems that exist in the multi-stage forming of the straight wall parts, such as the sheet fracture, uneven thickness distribution, and the stepped feature sinking, a new forming toolpath planning and generation method for the multi-stage incremental forming was proposed based on the stretching angle. In this method, the parallel planes that were used for forming toolpath generation were constructed by using the stretching angle so that the distances between the parallel planes and the forming angles were gradually reduced. This makes the sheet material flow become changed and the thickness thinning is relieved. The software system for the toolpath generation was developed by using C++, VC++, and OpenGL library. In order to verify the feasibility of the proposed method, numerical simulation and forming experiments were carried out for the single stage forming, the traditional multi-stage forming, and multi-stage forming based on the proposed forming toolpath, using 1060 aluminum sheets. The comparative analysis of the thickness distribution, profile curve, strain curve, and sheet material flow shows that the proposed method is feasible, and the profile dimension accuracy is better, the thickness distribution is more uniform, and the sinking and bulging are significantly reduced. The formed sheet part with the stretching angle of 15° has higher dimensional accuracy, smaller bottom subsidence, and larger thickness than that of the stretching angle 5°.

Highlights

Sheet metal forming technology is continuously developing, with wide application and the improvement of plasticity of the sheet metal [1]
In order to solve the problem of the straight wall parts forming, many scholars proposed to add intermediate forming stages on the basis of the single stage forming to improve the formability of the single stage forming, that is, the multi-stage forming [8]
The results show that the third forming strategy can redistribute the sheet metal from the thicker area to the thinner area, so that the thickness distribution is more uniform

Summary

Introduction

Sheet metal forming technology is continuously developing, with wide application and the improvement of plasticity of the sheet metal [1]. As a new sheet metal forming method, the sheet metal Computer Numerical Control (CNC) incremental forming has better formability than other conventional forming technology [2]. The demand for asymmetric parts and straight wall parts is increasing [6]. The single stage forming has some limitations in forming the straight wall parts with a large forming angle [7]. In order to solve the problem of the straight wall parts forming, many scholars proposed to add intermediate forming stages on the basis of the single stage forming to improve the formability of the single stage forming, that is, the multi-stage forming [8]. The research results show that the number of intermediate forming stages, forming toolpath, forming strategy, and forming direction

Results

Discussion

Conclusion