An Introduction To Sheet Metal Fabrication

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Sheet metal is simply metal formed into thin and flat pieces. It is one of the fundamental forms used in metalworking, due to the variety of different shapes it can help create. It has applications in car bodies, airplane wings, medical tables, roofs for buildings - countless everyday objects are constructed of the material. Historically, an important use was in plate armour worn by cavalry, and continues to have many decorative uses, including in horse tack.

Thicknesses can vary significantly, but the general rule of thumb is that everything thinner than 6mm is considered sheet, everything over 6mm is considered plate. The thickness of the sheet metal is called its gauge. The gauge ranges from 30 gauge to about 8 gauge, the higher the gauge, the thinner the metal.

There are many different metals that can be made into sheet metal, such as aluminum, brass, copper, steel, tin, nickel and titanium. For decorative uses sych as jewellery, important metals include silver, gold, and platinum.
There are several forming processes, the following being the most common:-

Bending - produces a V-shape, U-shape or channel-shape along the flat axis of the sheet. Large, industrial machine presses are generally used for this sort of shaping, with common products being metal boxes (electrical housing, connection points) and ducts (heating, ventilation).

Curling - used to form the edges of a sheet into a hollow ring. Curling can be performed to eliminate sharp edges or to increase the moment of inertia near the curled end. Other parts are curled to perform their primary function, such as door hinges.

Decambering - process of removing the camber, or horizontal bend, from an already-formed strip sheet. The process of producing sheet can sometimes leave the deformation of a camber, and this is then rolled out.

Deep drawing - achieved by a gradual stretching of the sheet over a form/mould. 'Deep' drawing is defined by the depth of the impression made being more than half its diameter. Common products produced in this way are fuel tanks, kitchen sinks and food tins.

Ironing - process of uniformly thinning the work piece in a specific area. It's a very useful process when employed in combination with deep drawing to produce a uniform wall thickness yet with greater height-to-diameter ratio; ironing can be found in the manufacture of aluminum beverage cans, which are actually pressed from flat sheets of thicker material.

Stamping - includes a variety of forming processes, including punching, embossing, flanging and coining. Both simple and complex shapes can be formed at high production rates using this method; tooling and equipment costs can be high, but the subsequent labour costs are usually low.

These are just some of the techniques used all over the world to form and create sheet metal objects. Sheet metal is one of Mankind's ultimate products - hardy, long-lasting yet flexible and often beautiful, it can be formed into boxes, hinges, pipes, ducts, domestic utensils, structures, jewellery and even toys.
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Jeffery Nevil has 1 articles online

Jeffrey Nevil writes on a number of subjects including Sheet Metal Fabrication, Sheet Metal Fabricators and Metal Bending.

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An Introduction To Sheet Metal Fabrication

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This article was published on 2011/01/04