Working With Sheet Metal

Sheet Metal is a flat shaped product made from metal that can vary in thickness between 0.015cm and 6.32cm. Very thin pieces would be considered foil/leaf pieces while thicker pieces are called plates.

The reason why sheet metal is widely used is because it can be easily changed in to a variety of shapes. Through a wide variety of processes sheet metal machinery and tools are used to do this.

Stretching
Sheet metal can be straightened by using a grip at either side of the sheet and stretching it. The sheet metal machinery and tools used to do this are able to pull the sheet metal beyond its elastic limit allowing it to come out flat. The affect of the stretching is that its temper will be slightly raised.

Stamping
This is a process that may involve one or more stamping stations to perform various actions on a metal sheet to create a final workpiece. As the metal sheet is passed through the work stations each one alters the shape by cutting, forming or drawing the piece. Each stamping station contributes to the final piece.

Cutting
There are a number of ways that Sheet metal can be cut, ranging from manually cutting the sheet using tin snips to using computer aided laser cutting. Tin snips can be extremely tricky - even frustrating to use, especially when the sheet curves. The use of computer controlled laser cutting allows for greater accuracy while at the same time reducing the amount of waste.

Laser cutting involves focusing a beam of laser light over the sheer metal heating and subsequently burning the metal. The edge of the sheet will be very smooth. Old Trumpf equipment laser cutters can be used to get a precision of around 0.01mm.

Bending
Bending can be carried out by sheet metal machinery and tools and is done to shape the sheet into various forms. A pressbrake is used to bend the metal into a shape that is determined by its die set.

Shearing
When the sheet metal is too big for use, then the sheet needs to be cut to size. This process is called shearing. This step needs to be carried out before any stamping can be started. Sheet metal machinery and tools ‘shear’ the sheet metal until the desired size has been achieved.

Deep Drawing
The deep drawing process involves sheet metal machinery and tools ‘punching’ blank sheet metal into a die set. It thus involves a transformation of the sheet metal into a desired shape.