Sheet metal is a comprehensive cold working process for thin metal sheets (usually under 6mm), including shearing, punching/cutting/laminating, bending, riveting, splicing, forming (such as car bodies), etc. Its notable feature is that the thickness of the same part is consistent.
There are numerous sheet metal materials suitable for stamping processing.
The sheet metal materials widely used in the electronics and electrical industry include:
1. Common cold-rolled steel plate SPCC: SPCC refers to the contin uous rolling of steel ingots into steel plate coils or sheets of the required thickness through a cold rolling mill. The surface of SPCC has no protection at all. When exposed to the air, it is extremely prone to oxidation, especially in a humid environment where the oxidation rate accelerates, resulting in dark red rust. When in use, the surface needs to be painted, electroplated or otherwise protected.
2. Galvanized steel sheet SECC: The base material of SECC is common cold-rolled steel coil. After going through degreasing, pickling, electroplating and various post-treatment processes on a continuous electro-galvanizing production line, it becomes an electro-galvanized product. SECC not only possesses the mechanical properties and similar processability of general cold-rolled steel sheets, but also features superior corrosion resistance and decorative appearance. It has great competitiveness and substitutability in the markets of electronic products, household appliances and furniture. For instance, SECC is commonly used in computer cases.
3. Hot-dip galvanized steel sheet SGCC: Hot-dip galvanized steel coil refers to the semi-finished products after hot-rolled pickling or cold rolling, which are cleaned, annealed, and then immersed in a molten zinc bath at about 460°C to coat the steel sheet with a zinc layer, followed by quenching and tempering, leveling, and chemical treatment. SGCC material is harder than SECC material, has poorer ductility (avoid deep drawing design), a thicker zinc coating and poorer weldability.
4. Stainless steel SUS301: The Cr (chromium) content is lower than that of SUS304, and its corrosion resistance is poorer. However, after cold working, it can achieve excellent tensile strength and hardness, and has good elasticity. It is mostly used for spring pieces, springs, and EMI protection.
5. Stainless steel SUS304: One of the most widely used stainless steels, it is more corrosion-resistant and heat-resistant than steel containing Cr (chromium) due to its Ni (nickel) content. It has excellent mechanical properties, no hardening after heat treatment, and no elasticity.
Sheet metal features light weight, high strength, electrical conductivity (suitable for electromagnetic shielding), low cost, and excellent performance in large-scale mass production. It has been widely applied in fields such as electronics and electrical appliances, communications, the automotive industry, and medical devices.
For instance, in computer cases, mobile phones, and MP3 players, sheet metal is an indispensable component. With the increasingly widespread application of sheet metal, the design of sheet metal parts has become a crucial part of the product development process.
Mechanical engineers must be proficient in the design techniques of sheet metal parts to ensure that the designed sheet metal not only meets the functional and appearance requirements of the product but also simplifies the manufacturing of stamping dies and reduces costs.