News Center
Blog
A Brief Analysis of the Causes of Wrinkling, Material Overlap, and Cracking in Stamped Flanges
Release Date:
2021-09-29
In the design of automotive body stampings, a two-stage flanging configuration is a very common structural feature, serving to increase the overlap area for part mating and welding as well as to enhance part strength.
In the design of automotive body stampings, a double-flange configuration is a very common structural feature, serving to increase the overlap area for mating and welding as well as to enhance part strength. However, during the stamping process, such double-flange structures often exhibit defects such as flange wrinkling, material overlapping at the flange, and flange cracking, which degrade part quality. When these issues occur in stampings for critical areas of the vehicle body, they can reduce body structural integrity and even compromise occupant safety.
In the design of stamped parts, three main types of flanging structures are commonly used: flanging the edge of a flat section of the part; flanging the edges on both sides inward during bending; and flanging the edges on both sides outward during bending.
For bent and inward-flanged structures, the conventional forming process involves first bending to shape the part and then performing flanging on the flange surface. A common defect in such parts is wrinkling at the flange area caused by the second flanging operation.
Bending and outward-flanging structures typically employ two forming methods: one is the draw-and-flange process, in which the flange surface of the part after secondary flanging is prone to wrinkling defects; the other is a two-step forming process that first performs single-stage flanging followed by secondary bending, in which the material edge at the secondary-bent portion of the flange surface is susceptible to cracking.
There are many causes of cracking in stamped parts; however, the root cause is that, during forming at the crack location, the degree of stretching exceeds the material’s ultimate tensile strength—that is, the amount of tensile strain during the forming process surpasses the material’s maximum allowable elongation.
For raw materials used in stamping production, no material stretching occurs. During bending or flanging operations, the material immediately adjacent to the punch face of the die typically also does not experience stretching. Therefore, for a double-flange structure, when assessing the risk of cracking at the flange edge, it is sufficient to determine whether the amount of material stretching at the flange edge exceeds the maximum elongation limit of the selected material. To analyze whether the flange edge of a stamped part will crack, one need only calculate and evaluate whether the stretching strain exceeds the material’s allowable maximum tensile strain.
In the actual design of product parts, the flange-forming angle θ2 is closely related to the mating relationship among components, making it highly impractical to adjust during the design phase. The radius R2 of the flange-forming corner should be as small as possible; when R2 minus the material thickness is approximately 2–5 mm, the flanging requirements are generally satisfied. Moreover, the smaller R2 is, the larger the effective mating area of the flange surface, thereby improving the overall assembly quality of the product.
Based on the relevant calculation formula, to reduce the material’s elongation ratio δ during the two flanging operations, feasible design and control measures for the stamped part include shortening the length of the blank edge at the flanging section of the flange surface—i.e., reducing the value of h—and increasing the bend radius R—i.e., increasing the value of R1. However, increasing the bend radius R is prone to cause springback defects in the stamped part.
Related News
Advantages of Deep Drawing and Stamping Processes
2021-09-29
Deep-drawn stampings are stamped parts formed by pressing, drawing, or using metal dies to deform sheet metal into cylindrical or box-shaped configurations.
Summary of the Advantages of the Red Punching Process at the Stamping Plant
2021-09-29
The red-hot stamping process employed in stamping fabrication plants is an advanced hot-pressure forming technique that delivers significant market-driven economic benefits for high-volume production. Consequently, research and development of this process hold broad and far-reaching practical significance for applications in mechanical manufacturing, everyday hardware products, national defense, aerospace components, and other fields.
A Brief Analysis of the Causes of Wrinkling, Material Overlap, and Cracking in Stamped Flanges
2021-09-29
In the design of automotive body stampings, a two-stage flanging configuration is a very common structural feature, serving to increase the overlap area for part mating and welding as well as to enhance part strength.
2021-09-29
Among all the factors contributing to die failure, die material and heat treatment account for approximately 70%, making them the primary determinants of die service life.
Online Message
If you have any suggestions for our company or demand for our products, please contact us according to the contact information provided below, thank you very much for your continued support and attention to us!
Contact Information
Address: No. 1-1, Xilin Town, Zhonglou District, Changzhou City
Contact: Manager Wang
Phone:13616111992
Email:656400@qq.com
Mobile website
Copyright 2026 © Changzhou Inoxon Metaltech Co.,Ltd.
