Mold is a variety of molds and tools used in industry to obtain the required products by injection molding, blow molding, extrusion, die casting or forging, melting, stamping and other methods. This tool is composed of various parts, and different molds are composed of different parts. It mainly realizes the appearance of articles through the change of physical state of molding materials. Metal dies are classified according to the process adopted, and commonly used are: stamping dies, including blanking dies, bending dies, drawing dies, hole-turning dies, hole-shrinking dies, wave-shaped dies, bulging dies, shaping dies, etc. The following is a brief introduction to common molds:

I. Stamping die

Stamping die is used for stamping and separating sheet metal. The mold for forming has a cavity, and the mold for separating has a cutting edge. The stamping die is characterized by high precision, accurate size and fast stamping speed, which can be stamped dozens to thousands of times per minute; The die life is long, and the life of some silicon steel sheet blanking dies is more than several million times.

(1) The most commonly used stamping die has only one station to complete one process. This kind of mould is widely used, simple in structure and easy to manufacture, but its efficiency is low.

(2) In order to improve efficiency, multiple stamping processes such as blanking, drawing, punching and trimming can be arranged on one die, so that the blank can complete multiple stamping processes on one station. This kind of mould is called compound mould.

(3) In addition, blanking, bending, stretching, punching and trimming are arranged at different stations of the die. In the stamping process, the blank goes through several stations in turn for continuous stamping and finally becomes a part at the last station. This kind of die is called progressive die, also called continuous die.

Second, forging die

Forging die is a die used to forge hot metal. The technical characteristics of forging die are: many complicated cavities; The die should bear the high-speed impact of the forging hammer or the reduction of heavy load; In the process of use, it is often in a state of rapid cooling, rapid heating and alternating cold and hot. Therefore, the mold material should have high strength, toughness and wear resistance. Hot forging must also have high temperature strength and hardness and undergo toughening heat treatment.

(1) In the process of die forging, the blank is often deformed many times before it can be made into forgings, which requires carving several cavities on a module.

(2) metal is sent into each cavity in turn, flows plastically in the cavity, and finally fills the cavity to make forgings.

(3) In die forging, it is difficult for the blank to be equal to the cavity volume in the final forging. In order to avoid waste, a slightly larger blank is often selected.

(4) A flash groove is arranged around the cavity at the interface between the upper die and the lower die of the final forging die to store excess metal, and the flash is cut off after forming.

Third, the extrusion die

Extrusion die is a die used to extrude metal. Because the metal needs to be extruded from the die under great pressure, and the extrusion cylinder and the reverse extrusion die need high strength, the multi-layer prestressed composite structure is often used.

(1) The positive extrusion die has a static female die, an extrusion cylinder for placing the blank and a punch for applying pressure to the blank.

(2) The extrusion barrel of the reverse extrusion die is a female die, and the punch is a male die.

(3) The punch and the length of the punch should be short to avoid instability and bending under high pressure stress.

Fourth, die casting mold

The die casting die is installed on the die casting machine, which can inject liquid metal into the cavity under high pressure and keep the pressure until the metal solidifies and forms. Die castings are generally thin, hollow, with many platforms and ribs, complex shape and structure, accurate size requirements and smooth surface. Because metal is formed at high temperature, the die-casting mold needs to be made of high-temperature resistant materials.

(1) is mainly used for aluminum, zinc and copper parts, and can also be used for steel parts.

(2) The structure of the die casting mold is similar to that of the injection mold. It consists of a moving die and a fixed die, and the core is used as the cavity of the casting.

(3) After the metal is cooled and solidified in the cavity, the core is taken out and the mold is separated.

The above are common metalworking molds, and the manufacturing methods of molds for different purposes are different. The more common manufacturing methods are cutting and casting.