Metal mold knowledge

The mold is classified according to the processing technology of the processing metal. Commonly used are: stamping molds, including blanking molds, bending molds, drawing molds, turning hole molds, shrinkage cavity molds, lifting molds, bulging molds, and plastic molds; forging molds, Including forging die, forging die, etc.; and extrusion die and die casting die. The molds used to process non-metal and powder metallurgy are named and classified according to the processing object, including plastic molds, rubber molds and powder metallurgy molds.

1. Stamping die used for sheet metal stamping and separation. The forming mold has a cavity, and the separating mold has a cutting edge. The most commonly used stamping die has only one station to complete a production process. This kind of mold is widely used, simple in structure and easy to manufacture, but its production efficiency is low. To increase productivity, multiple stamping processes, such as blanking, deep drawing, punching, trimming, etc., can be arranged on a single die to allow the blanks to complete multiple stamping operations at one station. This type of die is called a compound die. . In addition, multiple processes such as blanking, bending, deep drawing, punching and trimming are arranged in different positions of a mold. 2. Forging die for hot metal die forging die. When forging, the billet often undergoes multiple deformations to make a forging, which requires the engraving of several cavities on one module. The metal is sent to each cavity in turn, plastically flows in the cavity, and finally the cavity is filled with forgings. In forging forming, the billet is difficult to be equal to the volume of the cavity during final forging. In order to avoid the waste, the billet is selected slightly larger. For this purpose, a flash groove is provided around the cavity of the upper and lower mold interface of the final forging die to store excess metal, and the flash is cut after forming. The sharp corners and deep grooves should be minimized in the cavity to facilitate metal plastic flow and filling, reduce mold wear and cracking, and increase die life. 3. The extrusion die is used to mold the metal extrusion die. The positive extrusion die has a stationary die and an extrusion cylinder for placing the blank and a punch for applying pressure to the blank. When extruding the hollow member, the plunger has a mandrel at the front end. The extrusion cylinder of the counter extrusion die is a female die and the punch becomes a male die. Metals need to be extruded from the die at very high pressures, and the required pressure in the cold state can be as high as 2000 kN/mm (200 kg/mm). For this reason, the extrusion cylinder and the counter-extrusion die need to have high strength, and a multi-layer pre-stressed composite structure is often used. The working length of the punch and punch should be short to avoid instability and bending under high compressive stress. 4. The die casting mold is mounted on the die casting machine. The liquid metal is injected into the cavity under high pressure and the pressure is maintained until the metal solidifies and forms the mold. It is mainly used for aluminum, zinc, copper parts, but also for steel parts. The structure of the die casting mold is similar to that of a plastic injection mold. It consists of a movable mold and a fixed mold to form a cavity. The core is used to form the cavity of the casting. After the metal is cooled in the cavity and solidified, the core is withdrawn, the mold is separated, and the ejector ejects the casting. Die castings are generally thin-walled, with numerous tables and ribs, complex shapes, precise dimensions, and a smooth surface. Metals are formed at high melting temperatures. Therefore, die-casting molds need to be made of materials that are resistant to high temperatures. 5. Powder Metallurgy Mold A mold that compacts a solid metal powder. The metal powder is quantitatively poured into the lower die, which is then overmolded, closed, shaped, and the preform is ejected with the tipping device. The preforms are fed into a sintering furnace and sintered to make powder metallurgy parts. General powder metallurgy parts of the large space, accounting for about 15% of the total volume, the forming pressure is not large, the mold structure is relatively simple, precision, surface roughness requirements in general, so no special requirements on the mold. In order to reduce voids and improve density and strength, the sintered blanks are further subjected to hot forging, commonly known as powder forging. The die used is similar to the die forging die.