Sheet Metal Hem Design

They are used to strengthen part edges.

Sheet metal hem design.

In car part production hemming is used in assembly as a secondary operation after deep drawing trimming and flanging operations to join two sheet metal parts outer and inner together. Hems are commonly used to hide imperfections and provide a generally safer edge to handle. It is easy to work with and very attractive in the home. To fasten two sheet metal parts to improve the appearance of edges remove burrs and rough edges and to increase the part stiffness.

A sheet metal forming operation in which the edge of the sheet is folded back on itself. We recommend that the minimum inside diameter equals the material thickness and the hem return length is 6 times material thickness. This is putting a simple hem on a curved piece of zinc with a 7ft radius. Hems are most often used to remove a sharp untreated edge and make it safe for handling.

The md building products 36 in. X 36 the md building products 36 in. Bend a flange all the way over and you have a hem. Typical parts for this type of assembly are hoods doors trunk lids and fenders.

Closed hems are basically flat with the material folded over completely on itself. Some of the common sheet metal design guidelines included are minimum distance between holes cutouts slots distance between holes cutouts slots to part edge and bends multiple bends in same direction minimum bend radius minimum radius of rolled hem open hem and tear drop hem minimum flange width minimum size of slots holes and many other design guidelines. In sheet metal hems are used to create folds in sheet metal in order to stiffen edges and create an edge safe to touch. Hem is equal to the material thickness with a return flange height equal to or greater than four times the material thickness.

It serves several purposes. The minimum return flange height of a closed hem is equal to or greater than four times the material thickness the diameter is zero. The tolerance of a hem is dependent upon the hem s radius material thickness and features near the hem. We form closed hems folds at the end of a part to create a rounded edge.

Mill aluminum union jack style perforated sheet metal offers a decorative way to complete your hvac door window hobby and cabinet projects. Create a bend with acute angle tooling in the metal 30 is preferable but 45 will work for some circumstances. Dfmpro provides pre configured design guidelines dfm best practices which helps to develop better quality parts at reduced cost. Closed hems tend to fracture at the bend and cause.

The sheet features a union jack style perforated design. Hemming is also critical to the overall part functionality as well as assembly quality.