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.