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

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°.

Investigation of the Effect of SPIF Parameters on the Thickness of Al 2024 Alloy

“…The results from the numerical analysis agreed well with those from the experimental work. Moreover, Zhu et al [12] presented the forming tool path generated using the stretching angle in the multiincremental forming process. The material used is aluminum alloy (Al 1060) with a thickness of 1 mm, and the tool path was generated using C++, VC++, and the OpenGL library.…”

Recent Developments and Future Challenges in Incremental Sheet Forming of Aluminium and Aluminium Alloy Sheets

“…Awankar et al [177] hinted that the thinning in the mid-zone of the sheet is because the material is encountering uniaxial stretching from both sides in this area. Zhu et al [178] generated a new toolpath method to form straight wall components from 1060 aluminium sheets by multistage forming to eliminate the inhomogeneity in the thickness of the final product. In their method, the toolpath is based on parallel planes adopting a stretching angle to minimise the distance between the wall angle and the parallel planes.…”

Research on the Negative Multistage Incremental Forming of Straight-Wall Parts Based on the Extrusion from the Forward and Reverse Side of the Sheet

“…The second-and third-stage forming toolpath adopt the parallel toolpath with a stretching angle [33]. When generating the third-stage forming toolpath, it should be noted that in the extrusion from the forward and reverse sides in the second-stage forming and the third-stage forming, creases may occur at the height H of the straight-wall part.…”