Metal stamping is a metalworking process that uses dies to create shapes out of sheet metal. A die is a tool used to shape the metal and is made from various materials, including steel, brass, aluminum, or plastic.
The most common types of metal stamping are done with steel dies. Steel is a durable material that can withstand the wear and tear of the stamping process. However, other materials are also be used for making dies, such as brass and aluminum. Brass is a softer metal than steel, so it is not as durable but has higher corrosion resistance. Aluminum is also a softer metal than steel, but it is lightweight and has excellent corrosion resistance. Plastic is the least durable material for making dies, but it is the cheapest and lightest option.
The design of the die is critical because it ensures the desired shape is created in the metal. The die must be appropriately aligned with the sheet metal and have the right contours to create the desired profile. Various software programs are used to make die designs, such as AutoCAD and SOLIDWORKS. Once the design is complete, it is sent to a die maker who creates the die using computer numerical control (CNC) machines.
The stamping process is performed using a press that exerts extreme pressure on the die. This causes the metal to deform and take on the shape of the die. The amount of energy required to bend the metal depends on the thickness of the sheet metal and the size of the die. The thicker the metal, the more force is needed to deform it.
The following processes are employed to make metal parts using stamping dies.
Punching
Punching comprises placing a flat sheet of metal on the die and striking it with a punch to create a hole. The punch is a rod attached to a hammer. The force of the punch deforms the metal, creating a hole.
The size of the hole created is determined by the size of the punch and the contours of the die. If the punch is too small, it will not make a hole in the sheet metal. If the punch is too large, it will deform the metal beyond its ability to reform, simply creating a flaw.
Flanging
Flanging creates a lip on a metal sheet. The flange may, for example, be used as part of a wheel hub or other wheel-related components. Flanging is also known as wheeling, and it’s performed by swaging, which is a type of cold metalworking. The word swage comes from the French en swaider, which means to swell or expand. It was first used in metalworking in the 15th century.
To form a flange, you need the appropriate die. It must have two types of contours—the crown and the curl. The crown contour should gradually rise from the base edge and reach its maximum height in the middle, then flatten progressively outward. The curl contour starts high at the center of the flange, then curls downward.
This metalworking die can be used to form wheels for heavy-duty trucks and other industrial equipment.
Piercing
Metal piercing uses a die with raised patterns or shapes on its surface. The die’s body causes the metal to deform to match its shape, creating pierced holes in the sheet metal when it contacts sharp points in the die pattern. Piercing can also be accomplished with a blanking press.
Blanking
Blanking is another term for punching.
Drawing
Drawing is used to decrease the thickness of metal sheets or rods using a die.
Rounding
As the term implies, rounding is the process used to give metal sheets a curved shape. The curved shape can be used for various purposes, for example, creating body panels for cars or trucks. It can also be used for making parts that must fit together, such as brackets.
Extrusion
Extrusion processes involve forcing material through an orifice in the die, using pressure or suction, applied in an axial direction along a specially shaped cavity produced by a punch and die. In this process, the metal is forced through a progressively smaller series of dies until it reaches the desired diameter.
Parting
Parting is used to divide solid materials into parts using a cutting tool called a parting tool. The most common example of parting is used on castings, which are cast with a parting line that defines the two halves. This process is also used on sheet metal or forged steel metal blocks.
Shearing
Shearing describes a mechanically applied force used to separate the metal into two parts. These two parts are mirror images of each other. This process is used to create straight edges on metal sheets, such as aluminum.
Bending
Bending creates a bend in a piece of metal using a machine that provides pressure or suction. A typical example would be bending steel into hairpins for hairstylists, where it is crucial to have a strong material that keeps its shape. This process does not cause any significant loss in mass, and works well with most metals, including brass and aluminum.
Conclusion
There are many processes available to shape metal into useful objects. The common ones are cutting, stamping, parting, shearing, piercing, drawing, rolling, forging, and bending. Each one serves a specific need that must be considered when choosing the proper processes for the job.
