Sheet Metal Hem Radius

Minimum acute punch radius for aluminum minimum flat length x 2 hemming and seaming hemming and seaming are basically the same process.

Sheet metal hem radius.

A seam is a method of joining two pieces of sheet metal together figure 5. 22 gauge 0 030 0 76 mm 0 5 12 7mm. Generally capabilities of of 0 9mm 20mm in thickness are able to be manufactured from sheet 3mm or plate 3mm but this tolerance depends mainly on the part. In sheet metal hemming means to fold the metal back on itself.

In low carbon steel sheet metal the minimum radius of a bend should be one half the material thickness or 0 80 mm 0 03 inch whichever is larger counterbores the minimum distance between two counterbores is eight times the material thickness. It is recommended to use the same radii across all bends and flange length must be at least 4 times the material thickness. For bent sheet metal variation in the raw material thickness increases the recommended precision to 0 010 in. Layout method sheet metal stretches when it bends is an oversimplification.

Runs right at the limit of precision flat sheet metal in a job shop environment. Curling sheet metal is the process of adding a hollow circular roll to the edge of the sheet. When considering sheet metal thickness a single sheet with punches holes is a good rule of thumb. As a general recommendation 0 005 in.

Curling is different than a tear drop hem because in a curl the edge finishes inside itself where a hem leaves the initial edge exposed. If the hem has a radius greater than zero it resembles a u in cross section. 22 gauge 0 030 0 76 mm 0 2 5 08mm. The hem is primarily used for reinforcement safety and edge appearance figure 4.

22 gauge 0 030 0 76 mm. When working with a brake press hems are always created in a two step process. Unlike the u channels discussed in part iii the hem has only one bend instead of two. 22 gauge 0 030 0 76 mm 0 375 9 52mm.

Flange length must be at least 4 times the material thickness. This is an industry standard and most cost effective. Our bend radius option is 0 030 in 0 762mm. A hem is a single 180 degree bend.

Some hems are closed basically a zero inside bend radius. The curled edge provides strength to the edge and makes it safe for handling.