Wednesday, January 03, 2007

A Look at Sheet Metal Stamping

Sheet metal stamping is the system wherein metal sheets are used for producing final products. When a metal sheet is inserted into the die or the press, it is molded into the required shape and size. Metal sheets of only a certain thickness can be inserted into metal stamping machines. The maximum limit for most metal stamping machines is ¼ inch. However, machines can be designed to accommodate sheets of greater thickness also. Even the kind of metal sheets that can be processed in metal stamping are also specific. Only certain metals or alloys can be used like aluminum, brass, steel (hot rolled or cold rolled), galvanized steel, stainless steel, copper, zinc and titanium.

Before the metal sheet is inserted into the machine, the customer provides the prototype or at least a diagram of the final product. In case the customer doesn’t have a clear idea of what the final product should look like, most metal stamping producers also offer engineering services for designing the products as well. Even some secondary services such as deburring and plating are provided by the metal stamping companies after the metal sheet is stamped.

There are three main components in sheet metal stamping -- the die, the punch and the binder/blank holder. The sheet is kept between the blank holder and the die and the punch is driven into the die wherein the sheet spreads over the die because of the drawing and stretching. The blank holder provides the restraining force that is required to control the sheet flow into the die. This force prevents wrinkling and tearing of the sheet as the quantity of material going into the machine can be controlled. For some processes where the blank holder force is too high for the material, draw beads are used to create the restraining force.

Sheet metal stampings are also known as thin stampings. Sheet metal stamping is used most primarily in the case-building process. It is also the most important part as each of the panels has to be stamped one by one. First the motherboard tray is stamped, then one-side panels on the right and left from bottom to top and back.