Metal forming (METAL FORMING PROCESS) or metal stamping refers to a type of manufacturing process that changes the shape of raw materials into products or workpieces with the desired shape. Sometimes called metal stamping according to the model, using a mold or specific tool (DIE or FORMING TOOL) to form while the raw material is in a solid state, without scrap and without changing the internal composition of the material. This is different from the turning process (MACHINING PROCESS), which is a production that has scrap, or metal casting (CASTING PROCESS) that changes the state of the raw material from solid to liquid.
Metal stamping is one of the manufacturing processes for structural parts and components of electrical appliances, cars, aircraft, and parts of many types of industrial machinery. It is a step that occurs after the process of extracting, casting, and compacting metal powder. When the metal is formed from the metal stamping factory, it will enter the grinding, polishing, and painting processes until the metal workpiece is obtained. Then it is assembled with various parts, etc. In general, metal stamping can be classified into 2 parts:
1. Classified by starting material It can be divided into 2 types: sheet metal forming process and bulk metal forming process, which are as follows:
1.1 Sheet metal forming process consists of cutting, shearing (SHEARING PROCESS) is a method of cutting metal sheets with punches (PUNCH) or blades and dies (DIE) to obtain the desired shape for use in the next process. BENDING PROCESS is a metal forming process by folding metal up from a straight line until the metal has a curved shape, which makes the metal workpiece permanently transformed. Deep drawing (DEEP DRAWING PROCESS) is a change in sheet metal with three important tools: punches (PUNCH), dies (DIE) and blank holders (BLANK HOLDER) to make the metal workpiece have a depth greater than or equal to the diameter of the workpiece, for example, a soda can. Or food packaging, etc.
1.2 Metal stamping process consists of
• FORGING PROCESS is a process of transforming metal into a workpiece by using force, which can be done by hammering, impact forging. This forging method uses a closed die. As for squeezing, the workpiece must be prepared to be similar in size to the die to be used in the forming, which is often used in the production of metal workpieces that have a shoulder or edge shape.
• EXTRUDING PROCESS In this process, the workpiece is compressed or pushed into the opening of the die (DIE) and is pushed out using a mechanical or hydraulic press. The cross-sectional surface of the workpiece depends on the die (DIE) used. This method can make the formed metal workpiece have a complex and consistent cross-section along its length.
• ROLLING PROCESS is a process of reducing the thickness of the material or changing the size of the cross-sectional area of the material by applying pressure through the rollers. The metal workpiece will be sent between the rollers that rotate all the time, causing compression on the material. There are two types of rolling: flat rolling and shaped rolling, resulting in metal stamping work according to the desired design. There are also other traditional processes such as embossing, coiling, SWAGING, SHAVING and trimming.
2. Classified by metal stamping process, it can be divided into 2 types: hot working and cold working.
2.1 Hot working is a process that makes the metal high enough to form new crystals, but lower or lower than the temperature for melting the metal or material until it changes shape into a metal piece. There are many methods of hot metal stamping, such as:
• Forging
• Hot rolling
• Drawing & CUPPING
• Pipe welding
• Piering
• EXTRUDING
• Spinning
Advantages and disadvantages of hot metal stamping
The advantages of hot metal stamping are: It helps increase the density of the metal, reduce the porosity of the metal, reduce the size of the metal grains, impurities and embedded substances mixed in the metal will be broken into fine powder and dispersed in the metal evenly and combined into one substance, which results in better properties of the metal workpiece. And of course, there are advantages and disadvantages of hot metal stamping, which is the formation of oxides on the surface of the workpiece, which can cause the metal to decay, corrode and rust, and flakes on the surface of the metal workpiece, making the surface uneven and beautiful. And as we all know, heat causes the metal to expand or contract, and you cannot control the size of the workpiece.
2.2 Cold working metal stamping refers to the rolling process to permanently change the shape of the material or metal using a low temperature of about 20-25 degrees Celsius and does not cause new crystals to form. It consists of Methods as follows: BENDING, COLD ROLLING, EXTRUDING, SQUEEZING, SHEAR SPINNING, STRETCHING, STRAIGHT BENDING, SHOT PEENING, DEEP DRAWING, FORGING, HOBBERING
Advantages and disadvantages of cold metal stamping
The advantages of cold metal stamping are that it is an energy-saving and raw material-saving method because the metal workpiece does not need to be
The raw materials used for cold stamping are mostly sheets or strips with good surface quality, smooth, clean, shiny, strong, and also get the workpieces with precise size, according to the requirements because it uses large, stable machinery that can be processed into various parts with complex shapes, from the second hand to the car’s beam and cover.
And with cold metal stamping, it requires large machinery to stamp metal according to the model. Therefore, you may have to invest a lot in installing the machinery. In addition, in general, cold metal stamping factories tend to produce a single piece with high technical requirements. It may also make the production cost per piece of cold stamped metal quite high. Therefore, in order to reduce the cost per piece, it is popular for industries that require a large number of workpieces to be produced.
Industries that commonly use workpieces from cold metal stamping include machinery manufacturing, automotive manufacturing, aircraft, electronic engines, electrical appliances, light industry, and various measuring instruments, etc.
