Sheet metal corners are probably the most neglected elements of a part, and they are also among the most dangerous. There are a few solutions to the issue, though. Adding chamfers or radii to your design can vastly improve appearance, maintain structural integrity, and make your parts safer. These features take very little manufacturing time, they’re easy to design, and you’ll keep your end users safe.
Avoiding Sharp Corners with Chamfers
Chamfers replace dangerous, pointy sheet metal corners with flattened geometry. Imagine chopping the point off a triangle. As a designer, you have to consider placement. Cutting off the point to create a flattened area doesn’t have to leave you with two 45-degree angles. Still, best practices are to do that because it avoids creating two sharp points in the flat, and it yields nice symmetry. Best of all, most shops are already set up to create this sort of chamfer using a punch press. That helps reduce the cost to change tooling. Chamfers are typically used on internal parts where aesthetics aren’t as important or where the parts are hidden to the end user.
Avoiding Sharp Corners with Radii
Radii are another option and can be manufactured with either a laser or punch. When using a radius on a corner, you can easily reduce manufacturing cost by using industry standard tooling. For example, using standard radii such as 0.060 in., 0.090 in., 0.125 in., 0.187 in., or 0.250 in. will typically align with a manufacturer’s in-house tooling for corner radii. That makes punching parts quick and easy. Also, punching is often less expensive than laser cutting, though lasers free you from any geometric restrictions. Radius corners are typically used on parts that are more visible to the end user or where smoother lines are needed for aesthetics.
Comparing Chamfers and Radii
|COMPARING CHAMFERS AND RADII|
|Appearance||Use||Production Process||To Speed Production|
|Radius||rounded arc||aesthetic||laser or punch press||use standard radii|
|Chamfer||flattened to trapezoidal||functional||generally punch press||use 45-degree angles|
In the end, the choice of using a chamfer or radius on a sharp corner of a sheet metal part is the designer’s. Either choice removes the sharpness of the corner nicely, protecting your end users, and improving your part’s appearance.
Related Design Tips
For more helpful sheet metal design tips, download our Design for Manufacturing (DFM) Guide.