1、 Definition of sheet metal processing
Sheet metal processing is a kind of metal processing technology. Usually, some metal sheets are pressed by hand or die to produce plastic deformation to form the desired shape and size, and more complex parts can be formed by welding or a small amount of machining. It is mainly known as sheet metal cutting and riveting, which requires certain knowledge of sheet metal processing, such as cutting and riveting. Sheet metal parts are sheet metal parts, which can be processed by stamping, bending, stretching and other means. For example, the iron shell outside the car is sheet metal parts. The metal processing processes corresponding to the sheet metal process include casting, forging, machining, etc., and the metal thickness of its products is usually inconsistent.
2、 Sheet metal process classification
① Manual sheet metal
Only relatively simple tools are used, and most of the work is completed by hand. It is mainly concentrated in the fields of automobile repair, art, advertising and so on
② Stamping sheet metal
With the help of the power of conventional or special stamping equipment, the metal plate is directly deformed by the deformation force in the die, so as to obtain the production technology of metal plate products with specific shape and specification. It is only applicable to the product types with single variety, large output, small structure and relatively stable products
③ NC sheet metal
Using numerical control technology and equipment to carry out comprehensive cold deformation processing of metal plates, mainly including punching, cutting, folding, welding, riveting, surface treatment and other processes. It is suitable for products with small batch, many varieties and large size
3、 Characteristics of sheet metal stamping process
① The pressed products have good quality, such as smooth surface, high precision, relative stability and good interchangeability; Light weight, good rigidity and high strength; Stamping process can also process workpieces that are difficult to be processed by other processing methods, such as thin shell parts, workpieces with flanging, undulation, stiffeners, etc. The dimensional accuracy of cold stamping parts is guaranteed by the die, so the dimension is stable and the interchangeability is good
② Stamping products do not need or only need a small amount of cutting, with high material utilization and low material cost of workpieces.
③ High production efficiency, simple operation, easy to realize mechanization and automation. Equipped with advanced production line, it can realize the full-automatic mechanized operation of feeding, stamping, parts taking and waste removal, with low labor intensity.
④ The die used in press processing generally has complex structure, long production cycle and high cost. Therefore, stamping process is mostly used for batch and mass production, and single piece and small batch production are limited.
4、 Sheet metal material type
① Ordinary cold rolled sheet SPCC
SPCC refers to the continuous rolling of steel ingot into steel coil or sheet with required thickness by cold rolling mill. There is no protection on the surface of SPCC, which is easy to be oxidized when exposed to the air. Especially in humid environment, the oxidation speed is accelerated and dark red rust appears. The surface shall be painted, electroplated or otherwise protected during use.
② Galvanized steel sheet SECC
The substrate of SECC is a general cold-rolled steel coil, which becomes an electro galvanized product after degreasing, pickling, electroplating and various post-treatment processes in the continuous electro galvanized production line. SECC not only has the mechanical properties and similar processability of general cold-rolled steel sheets, but also has superior corrosion resistance and decorative appearance. It has great competitiveness and substitutability in the market of electronic products, household appliances and furniture. For example, SECC is widely used in computer chassis.
③ Hot dip galvanized steel plate SGCC
Hot dip galvanized steel coil refers to the semi-finished products after hot-rolled pickling or cold rolling, which are washed, annealed, immersed in the molten zinc bath with a temperature of about 460 ° C, and then coated with zinc layer, and then quenched, tempered, leveled and chemically treated. SGCC material is harder than SECC material, with poor ductility (avoiding deep pumping design), thicker zinc layer and poor weldability.
④ Stainless steel SUS301
The content of Cr (chromium) is lower than SUS304 and the corrosion resistance is poor, but it can obtain good tensile force and hardness after cold processing and has good elasticity. It is mostly used for shrapnel spring and anti em.
⑤ Stainless steel SUS304
One of the most widely used stainless steels, because it contains Ni (nickel), it is richer in corrosion resistance and heat resistance than the steel containing Cr (chromium). It has very good mechanical properties, no heat treatment hardening phenomenon and no elasticity.