Hemming and seaming are two similar

metalworking Metalworking is the process of shaping and reshaping metals to create useful objects, parts, assemblies, and large scale structures. As a term it covers a wide and diverse range of processes, skills, and tools for producing objects on every scal ...

processes in which a

sheet metal Sheet metal is metal formed into thin, flat pieces, usually by an industrial process. Sheet metal is one of the fundamental forms used in metalworking, and it can be cut and bent into a variety of shapes. Thicknesses can vary significantly; ex ...

edge is rolled over onto itself. Hemming is the process in which the edge is rolled flush to itself, while a seam joins the edges of two materials.. Hems are commonly used to reinforce an edge, hide burrs and rough edges, and improve appearance. Seams are commonly used in the food industry on canned goods, on amusement park cars, in

metal roof A metal roof is a roofing system made from metal pieces or tiles characterized by its high resistance, impermeability and longevity. It is a component of the building envelope. Zinc, copper and steel alloys are commonly used. History Copper has pla ...

ing (with a

roof seamer A roof ( : roofs or rooves) is the top covering of a building, including all materials and constructions necessary to support it on the walls of the building or on uprights, providing protection against rain, snow, sunlight, extremes of temper ...

), and in the automotive industry.

Process

The process for both hemming and seaming are the same, except that the tonnage (amount of force exerted) requirement is greater for seaming. The process starts by bending the edge to an acute angle. A flattening die is then used to flatten the hem.

Types

There are two types of hemmed edges: ''closed hems'' and ''open hems''. Closed hems are completely flush while open hems have an air pocket in the bend. The major difference is that the tonnage required for a closed hem is much greater than that for an open hem..

Process

Types

See also

References

Bibliography

Further reading