Metal stamping is a manufacturing process in which coils or flat sheets of material are formed into specific shapes. Stamping encompasses multiple forming techniques such as blanking, punching, embossing, and progressive die stamping, to mention just a few. Parts use either a combination of these techniques or independently, depending on the piece’s complexity.
Sheet Metal Stamping Applications
Metal stamped parts are used in a variety of applications, especially those involving three-dimensional designs, lettering, or other surface engraving features. Such metal stamping products are commonly produced for home appliance manufacturers, automotive companies, the lighting industry, telecommunications services, military and defense, aerospace industries, medical equipment manufacturers, and electronics companies. Odds are you have a product in your home that has parts created through metal stamping because it is a process used in everything from your household appliances to your cars.
The specific products and components can range from simple stamping items, such as metal clips, springs, weights, washers, and brackets, to more complex designs, such as those found in engine bases or friction plates. This process is used for producing both parts for large machinery and also incredibly detailed small parts. Micro precision metal stamping can create parts with diameters of up to 0.002 inches.
Electronic metal stamping are electronic components manufactured through the metal stamping process. They are used in a variety of industries, from home electronics and appliances to telecommunications and aerospace. Electronic stampings are available in several metals, including copper, copper alloys, aluminum, and steel, as well as more expensive metals, such as platinum and gold. Electronic components produced by the metal stamping method include terminals, contacts, lead frames, springs, and pins. They can be created from ferrous or nonferrous materials. Metal stampings find wide use in computers, electronic equipment, and medical devices. Because of the specialized shapes that can be made by the various stamping processes, many electronics are made by this cold forming process.
Design Concepts
Overly narrow projections should generally be avoided in stamped products, as these may be more easily distorted and impact the perception of quality in the finished product.
Where possible, designs should be based on the use of existing dies for standard shapes and bends. The need to create a custom die for stamping will increase initial tooling costs.
Avoidance of sharp internal and external corners in stamped product designs can help reduce the potential for the development of larger burrs in these areas and sharp edges that require secondary treatment to remove. Also, a great potential for stress concentrations exists in sharp corners, which may cause cracking or subsequent failure of the part through extended use.
Overall dimensions for the finished product are going to be limited by the available dimensions of the sheet metal sheets or blanks, and these limits need to be factored in for the material consumed in folds on edges or flanges and any additional material removal or use. Very large products may need to be created in multiple steps and mechanically joined together as a second step in the production process.
For punching operations, consider both the direction of punching as well as the size of the punched feature. Generally, it is best to do punching in one direction, so that any sharp edges produced by the punch will all be on the same side of the workpiece. These edges can then be hidden for appearance purposes and kept away from general access by workers or product end-users where they might represent a hazard. Punched features should reflect the thickness of the raw material. A general rule is that punched features should be at least twice the material thickness in size.
For bends, the minimum bend radius in sheet metal is roughly the same as the material thickness. Smaller bends are more difficult to achieve and may result in points of stress concentration in the finished part that may subsequently cause issues with product quality.
When drilling or punching holes, performing these operations in the same step will help to assure their positioning, tolerance, and repeatability. As general guidelines, hole diameters should be no smaller than the material thickness, and the minimum spacing of holes should be at least twice the material thickness apart from each other.
Bending operations should be performed with awareness of the risk of distorting the material, as the material on the interior and exterior surfaces of the bend point are compressed and stretched respectively. The minimum bend radius should be approximately equal to the thickness of the workpiece, again to avoid stress concentration build-up. Flange lengths should be more like three times the workpiece thickness as a good practice.