Tolerance Stackup and Sheet Metal Bending
It is important to note that as multiple bends compound off of each other, the likelihood of feature misalignment grows greater and greater. This likelihood of error and misalignment is caused by the relatively large tolerance band of sheet metal forming
When working with multiple bends on the same part, it is advisable to speak with the final manufacturer to get their feedback on potential design considerations to avoid these issues. Ultimately, if the part is intended to be manufactured in large quantities, first article prototyping should be done until the desired outcome is achieved through standard design principles. Some of these design principles include:
• Designing holes to be larger so that they absorb some of the variance in tolerance
• Incorporating alignment holes on the base of the sheet metal component so that the pieces can be mated together more easily during final assembly.
• Bending the components without the holes present, and adding the holes through additional post processing such as stamping or machining. While this approach has the highest chance of success, it is not recommended as the increase to overall production cost is not typically worth the ease of assembly.
Sheet metal bend radius is an essential factor to consider during metal forming processes like air bending or metal bending with a press brake. The bend radius refers to the curvature of a bend and is determined by the material type, thickness, and bend angle.
When performing metal bending, the tangent point is where the metal begins to bend, and the radius begins to form. It is crucial to maintain the tangent point at the correct location to ensure a proper bend radius. The metal bending tools and press brake used must be appropriate for the material type and thickness to ensure the correct bend radius is achieved without cracking or damaging the material.
The material type is a crucial factor to consider when determining the appropriate bend radius. The bend radius should be selected based on the material's ability to withstand deformation and not cause any stress or damage to the material.
When bending sheet metal, the bend angle should also be taken into account. The bend angle refers to the angle formed between the two adjacent surfaces of the metal after bending. The bend radius required for a particular bend angle will depend on the material type and thickness.
To achieve the correct sheet metal bend radius, it is crucial to use proper techniques, equipment, and tooling. Using the appropriate press brake and metal bending tools and following proper air bending or metal bending procedures can ensure a consistent and accurate bend radius. With careful consideration of all the factors involved, including material type, thickness, bend angle, and tangent point, high-quality sheet metal bending with the desired bend radius can be achieved.