This creates smooth round edges all around for holding the part from the hemmed edges. In a rolled hem, the bent portion of the sheet metal is tucked back into itself. Further pressing takes place making the second parts sit flush between the metal sheet and the returning flange and create a joint. The edge is bent in shape similar to an open hem and then the second piece to be connected is inserted into the gap between the metal sheet and the returning flange. Once the hem achieves the shape of an open hem, the returning flange is pressed onto the part surface through a flattening die. Rope hemĪ rope hem has a returning flange at a bent of more than 180 degrees. Teardrop hems are used for fragile materials such as aluminium. It is perfect for materials that do not have the required ductility to provide closed hems. The resulting shape resembles a teardrop. In a teardrop hem, the returning flange is bent beyond 180 degrees. The bend angle in this hem type is also 180 degrees. In an open hem, the returning flange is folded over the sheet metal but there remains an air pocket between the two. The inside radius is zero and thus, there is no gap between the returning flange and the metal sheet.Ĭlosed hems require a lot more power and tonnage from the presses than open or teardrop hems and it is also not advised for metal sheets that are over 2-3mm in thickness since the sheets are likely to fracture. The angle between the returning flange and the sheet metal is 180 degrees. In a flat or closed hem, the part of the edge that bends sits completely flush over the rest of the metal sheet. The different sheet metal hems based on the hem shape are as follows: They hide defects such as rough edges and burrs

They improve the surface appearance and surface quality The first stage creates an acute bend using acute tooling (V die) followed by a flattening of the return flange using a flattening die.Ī complete list of hemming benefits on a sheet metal product is as follows: The edge of one part may also be folded onto another part to create a joint.

Similar to how an edge stitch strengthens the edge and makes it more durable, a hem imparts strength to the metal edge and improves its appearance. It is very similar to edge stitching in clothes. Hemming in sheet metal operations refers to the bending of a sheet metal edge onto itself. III Hemming and Seaming Difference What Is Sheet Metal Hemming?

Solidworks sheet metal hem bend