Metal stamping is the process in which small, simple or complex shapes are punched-out in a continuous sheet of metal (blank) by using instruments such as punches and dies. Complex shapes are generated by successively stamping the metal sheet with punches of different shapes, starting with a rough shape, to the final punch. Stamping is a high volume production method and machines called presses that can generate 100 or more strokes per minutes are used. By using metal stamping, pieces of metal can be made into a three-dimensional object from a flat piece of metal. The object will also be stronger than if it was machined by any other process. Metal stamping can also be used on a piece of metal to make a relief design.
The die is made of hardened casing or hardened steel, while the punch is made of carbide or hardened, precision, ground, tool steel. The stamping machine or press may be powered by hydraulics, pneumatics or electric.
There are various types of presses that are used in metal stamping. A forge press is used to turn the metal piece into a three dimensional object. A press brake is used to bend the metal to force it to change its shape. A punch press is used to punch holes into the metal sheet. A set of rollers may be employed to make the metal pieces either thinner or wider. This is done by feeding the metal through the set of rollers to flatten it out. A set of plates can be used to stamp various designs or reliefs into the metal pieces
Optimum clearance between the die and the punch is required for increased tool life. Proper layout of the blank, punch and die must be done to ensure the minimum waste of the blank material, with just the right amount of wall thickness between adjacent punched parts. In addition, edge beading and shoulder forming can also be done. Metals such as brass, aluminum, bronze, fiber, inconel and steel can be stamped. There is a maximum sheet thickness up to which the metal can be stamped.
The most common type of metal stamping is called progressive die stamping. In this method, the metal is fed through a number of different dies, or stamping stations, at the same time. This process enables the piece to receive an assortment of shapes or impressions at once. The advantage of this is that it speeds up the procedure as the metal sheet doesn't have to be taken out and reinserted to a new die station each time.
Metal stampings are used in various industrial areas such as the electronic industry, for automobile components and for electric motors, etc. Metal stamping is also occasionally used for more artistic pursuits, such as custom tin ceilings.