Injection molding is the process of obtaining products after cooling in which the molten plastic of the injection machine enters the mold under the thrust of the plunger or screw. After the plastic is plasticized in the heating barrel of the injection molding machine, it is injected into the mold cavity of the closed mold by the plunger or reciprocating screw to form the plastic processing method of the product.
This method can process products with complex shapes, accurate size or with inserts, and has high production efficiency. Most thermoplastics and some thermosetting plastics (such as phenolic plastics) can be processed by this method. The material used for plastic injection molding must have good fluidity to fill the mold cavity to obtain the product.
1. Injection molding machine. It is composed of an injection device, clamping device, and injection mold. There are two expressions for the specification of the injection molding machine: one is the maximum injection volume or weight each time, and the other is the maximum clamping force. Other main parameters of the injection molding machine are plasticizing capacity, injection rate, and injection pressure.
2. The injection device is the main part of the injection molding machine. Heat and plasticize the plastic into a flowing state, and inject it into the mold under pressure. Injection methods include plunger type, pre plasticization type, and reciprocating screw type.
3. Mold closing device is used to close the fixed mold and moving mold, which can realize the opening and closing action of the mold to eject the finished product.
4. Injection mold. It consists of a gating system, forming parts, and structural parts.
① The gating system refers to the plastic flow channel from the nozzle of the injection machine to the cavity.
② Formed parts refer to the parts constituting the mold cavity, which are composed of the female and male die.
③ Structural parts include guiding, film stripping, core pulling, parting, and other parts. The molds are divided into a fixed mold and moving mold, which are respectively fixed on the fixed plate and a moving plate of the clamping device. The moving mold completes the opening and closing action with the movement of the moving plate. The mold can be heated or cooled as needed.