Sheet metal fabrication is a comprehensive cold processing technology for thin metal sheets (usually thickness below 6mm), including shearing, punching/cutting/laminating, folding/bending, riveting, splicing, forming (such as car bodies), etc. Its distinctive feature is that the thickness of the same parts can be maintained the same.

Sheet metal has light weight, high strength, and high conductivity (can be used in electromagnetic shielding), low cost, good mass production performance…etc. Sheet metal has been widely used in areas such as electronics, electrical appliances, communications, automobile industry, and medical. Applications include computer cases, mobile phones, and MP3…etc where sheet metal plays an essential part. As sheet metal is more and more widely used, the design of sheet metal parts has become very critical in product development process. Mechanical engineers must be proficient in designing sheet metal parts, so that the designed sheet metal not only meets the requirements of product functions and appearance, but also makes the stamping die simple to manufacture with low cost.

There are many sheet metal materials suitable for stamping and processing. Sheet metal materials widely used in the electronic and electrical industries include:

  1. Ordinary cold rolled sheet SPCC. SPCC refers to the continuous rolling of steel ingots into steel coils or sheets of required thickness by cold rolling mills. There is no protection on the surface of SPCC, and it can easily be oxidized when exposed to air, especially in the environment with high humidity, where the oxidation rate accelerates and rust in dark red appears. The surface should therefore be painted, electroplated or provided with other forms of protection when in use.
  2. Galvanized steel plate SECC. SECC’s substrate is a cold-rolled steel coil. After the continuous zinc plating production processes including degreased, pickled, electroplated and various post-treatment processes, it becomes a zinc plating product. SECC not only has the mechanical properties and approximate processability of general cold-rolled steel sheets, but also has superior corrosion resistance and decorative appearance. It is highly competitive in the market of electronic products, home appliances and furniture. For example, SECC is commonly used in computer cases.
  3. Hot-dip galvanized steel plate SGCC. Hot-dip galvanized steel coils refer to semi-finished products that are hot-rolled, pickled or cold-rolled. After cleaning, annealing, and immersing in a molten zinc bath with a temperature of about 460°C, the steel sheet is plated with a zinc layer, and then tempered, leveled and chemically treated. SGCC material is harder than SECC material, has lower ductility (avoid deep drawing design), thicker zinc layer, and lower weldability.
  4. The content of Cr (chromium) in stainless steel SUS301 is lower than that of SUS304, and its corrosion resistance is lower, but after cold processing, it can obtain good tensile strength and hardness, and has good elasticity. It is mostly used for shrapnel springs and anti-corrosion.
  5. Stainless steel SUS304 is one of the most widely used stainless steels. Owing to the fact that it contains Ni (nickel), it is more corrosion-resistant and heat-resistant than steel containing Cr (chromium). Also it has very good mechanical properties, but has no heat treatment hardening phenomenon and elasticity.

Generally speaking, the basic equipment for sheet metal crafting includes shear machine, CNC punching machine / LASER, plasma, water jet cutting machine, bending machine, drilling machine and various auxiliary equipment such as: uncoiler, leveling machine, deburring machine, spot welding machine etc.

Usually, the four most important steps of the sheet metal process are cutting, punching/cutting, folding/rolling, surface welding.

Sheet metal is sometimes made pull gold. The word comes from the English word “platemetal”, which is generally produced by stamping some thin metal sheets by hand or mold to create plastic deformation to form the desired shape and size, and can further form more complex parts through welding or a small amount of machining, such as chimneys, tin stoves, and automobile housings that are commonly used in households.

Processing of sheet metals is called sheet metal processing. For example, plates are used to make chimneys, iron drums, fuel tanks, jugs, ventilation pipes, elbow heads, round corners, funnel shapes, etc. The main processes are cutting, bending and crimping, bending and forming, welding, riveting, etc…Geometric knowledge is required for these processes.

Sheet metal parts are thin sheet metal parts. That is, parts that can be processed by stamping, bending, stretching, etc. A general definition is-parts with constant thickness during processing. The corresponding is the cast piece, forging parts, machined parts, etc., For example, the iron shell on the outside of a car is a sheet metal parts, and some cabinets made of stainless steel are also sheet metal parts.

Modern sheet metal crafting includes: filament power supply winding, laser cutting, heavy-duty processing, metal bonding, metal drawing, plasma cutting, precision welding, rolling forming, sheet metal bending forming, die forging, water jet cutting, precision welding, etc.

Surface treatment for sheet metal parts is also very crucial in sheet metal processing, because it has the effect of preventing parts from rusting and beautifying the product. The role of surface pretreatment of sheet metal parts is mainly to remove oil stains, oxidation and rust…etc. It prepares for surface post-treatment, and the post-treatment is mainly spraying (baking) paint, plastic spraying, and anti-rust coating.

In 3D software, namely SolidWorks, UG, Pro/E, SolidEdge, TopSolid, CATIA…etc, there are sheet metal parts. Designers can obtain the sheet metal parts required for processing mainly through the editing of 3D graphics. Designers can also provide data (such as expansion drawings, bending lines, etc.) to CNC punching machines / lasers, plasma, water jet cutting. machines (Laser, Plasma, Waterjet Cutting Machine) / Combination Machine and CNC Bending Machine.