In metal processing and stamping technology, flanging is a common forming process, widely used in automotive, aviation, household appliances, and electronic equipment fields. The flanging process not only improves the structural strength of parts but also enhances the appearance quality and connection performance. Among them, the flanging height is a key parameter in the flanging process, directly affecting the forming quality of parts, mold life, and subsequent assembly performance. Therefore, it is of great significance to scientifically and reasonably determine the flanging height in actual production.



One, Definition of Flanging Height



Flanging refers to the forming process in stamping, where the edge of a pre-punched hole or the edge of the sheet material is bent along a certain direction to form a vertical edge. The flanging height refers to the height of the vertical part of the raised edge after flanging, usually represented by h. It is one of the most important geometric parameters in flanging forming.



Two, Factors Affecting Flanging Height



1. Material Properties

The higher the plasticity of the material, the better its ductility, which can withstand greater deformation and therefore achieve higher flanging heights; conversely, brittle materials are prone to cracks during the flanging process, which limits the flanging height.



2. Flanging Coefficient (K)

The flanging coefficient is an important parameter for measuring the difficulty of flanging, defined as the ratio of the hole diameter before flanging (d) to the outer diameter after flanging (D) (K = d/D). The smaller the flanging coefficient, the greater the degree of deformation, and the higher the flanging height that can be achieved, but at the same time, the risk of cracks increases.



3. Punch Round Corner Radius

The round corner radius of the punch has a significant impact on the stress distribution during the flanging process. Larger round corners help to reduce stress concentration, thereby allowing higher flanging heights.



4. Lubrication Conditions and Mold Clearance

Good lubrication can reduce friction between the material and the mold, reduce forming resistance, and help achieve higher flanging heights. In addition, the gap between molds should also be reasonably set to avoid cracking due to too small gaps.



Three, Calculation Method of Flanging Height



In engineering practice, the commonly used formula for calculating flanging height is as follows:



For circular flanging holes:



$$

h = \frac{D - d}{2} \cdot \ln\left(\frac{D}{d}\right)

$$



In the formula:

- $ h $: Theoretical flanging height;

- $ D $: Outer diameter after flanging;

- $ d $: Original hole diameter.



This formula is based on the theory of material plastic deformation and is applicable to small deformation conditions of non-hardening materials. In actual application, it is necessary to make corrections in combination with factors such as material properties, process equipment, and mold structure.



Four, Experimental Verification and Optimization Design



After initially calculating the flanging height, it is usually necessary to verify through trial molding. By observing whether the formed quality after flanging shows cracks, wrinkles, springback, and other problems, it can be determined whether the flanging height is reasonable. If problems are found, the original hole diameter, punch round corner, material thickness, and other parameters can be appropriately adjusted to optimize the flanging height.



Five, Conclusion



In summary, determining the flanging height is a process that comprehensively considers material properties, mold structure, and process parameters. In actual production, it is not only necessary to rely on theoretical calculations as guidance, but also to adjust with experiments and experience. Only by scientifically and reasonably determining the flanging height can product quality be ensured, production efficiency improved, and waste rate and cost reduced. With the development of modern simulation technology, such as the application of finite element analysis (FEA), more precise tools are also provided for the optimization of flanging processes, which provides strong support for the design and control of flanging height.