Abstract

This paper introduced the basic principle and main influencing factors of the three‐dimensional multipoint stretch forming process and investigated the optimized scheme of the cross section forming quality. The main factors affecting the stretch forming process were studied by the orthogonal test through the numerical simulation technique. In the case of a good target shape, the best combination of forming parameters was established by using the range method. The cross‐sectional distortion of the formed profile is the smallest when the prestretching amount is 1% of the profile length, the poststretching amount is 0.8% of the profile length, the number of the die heads is 12, and the friction coefficient is 0.15. The optimal combination of forming parameters was verified by the multipoint bending test.

Highlights

  • Stretch forming is a method of bending parts under a combination of stretching and bending moments. e most challenging problem in the automobile industry now is to reduce the consumption of gasoline. erefore, lightweight structure design is attracting much attention, and the aluminum alloy is widely used due to its strong stiffness and lightweight [1]. ree-dimensional multipoint stretch forming is a rapid flexible forming technique which is different from the traditional bending forming

  • In addition to the common problems such as wrinkle, springback, and fracture in sheet forming, there are some special problems in the forming parts, such as cross-sectional distortion. e common problem of thin-walled section stretch forming is the cross-sectional distortion, and the main defects are collapse and bulging [4,5,6,7,8]

  • Proper prestretching and poststretching will affect the distortion of the cross section and change the precision of the forming part. e number of die heads affects the wrinkling and deformation of the profile during the bending process. erefore, this paper focused on the experimental factors including prestretching, poststretching, the number of die heads, and the friction coefficient, defining A as the amount of prestretching, B as the amount of poststretching, C as the number of die heads, and D as the amount of friction coefficient. e assessment index was the cross-sectional distortion of the stretch forming parts, and the collapse rate and the bulging rate were taken as the evaluation criteria

Read more

Summary

Introduction

Stretch forming is a method of bending parts under a combination of stretching and bending moments. e most challenging problem in the automobile industry now is to reduce the consumption of gasoline. erefore, lightweight structure design is attracting much attention, and the aluminum alloy is widely used due to its strong stiffness and lightweight [1]. ree-dimensional multipoint stretch forming is a rapid flexible forming technique which is different from the traditional bending forming. In addition to the common problems such as wrinkle, springback, and fracture in sheet forming, there are some special problems in the forming parts, such as cross-sectional distortion. E common problem of thin-walled section stretch forming is the cross-sectional distortion, and the main defects are collapse and bulging [4,5,6,7,8]. By using the numerical simulation technology, Paulsen and Welo made an arrangement for the degree of factors affecting the distortion on the cross section [9]. Miller et al did a detailed research on the influence of stretch-bending process parameters on formability, optimized the parameters, and got the conclusion that the tension force can reduce springback [10]. For different loading methods of two different aluminum profiles, Clausen et al used the experimental method and the finite element

Multipoint dies
Bending in horizontal stage Bending in vertical stage
Horizontal die Vertical die
Level A
Results and Analysis
Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call