The molds used to process non-metal and powder metallurgy are named and classified according to the processing object, such as plastic molds, rubber molds, and metal powder molds. The molds are classified according to the processing technology of the processed metal. Commonly used are stamping dies, forging dies, and extrusion dies and die casting dies. What are the differences between metal powder molds and their comparison?
The metal powder mold is a mold for compacting a solid metal powder, and the metal powder is quantitatively poured into the lower mold, and then the mold is pressed down, closed, and formed, and the preform is ejected by the ejector device. The preforms are fed into a sintering furnace and sintered to make powder metallurgy parts.
General powder metallurgy parts have large voids, accounting for about 15% of the total volume, forming pressure is not large, the mold structure is relatively simple, precision, surface roughness requirements in general, so no special requirements for metal powder 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.
If a die casting die is used as the die, the die casting die needs to be mounted on the die casting machine. The liquid metal is injected into the cavity under high pressure and pressure is maintained until the metal solidifies and forms. It is mainly used for aluminum, zinc, copper parts, and also for steel. Pieces. The die-casting mold is composed of a movable mold and a fixed mold to form a cavity, and 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 After the metal is cooled in the cavity and solidified, the core is withdrawn, the mold is separated, and the ejector ejects the casting.
The forging die is used for the hot metal die forging die. When die forging, the blank often undergoes multiple deformations to make the forging, which requires engraving several cavities on a module. 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.
The extrusion die is used for the metal powder mold that presses the metal. 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; and the extrusion die for the back extrusion die For the die, the punch becomes a punch, and the metal needs to be extruded from the die at a large pressure.