Injection Mold Processing And Mold Process

Mold injection molding is a processing method used in mass production of complex parts of certain shapes. The specific principle refers to: the plastic raw material that is heated and melted is pushed by the screw of the injection molding machine into the cavity of the plastic mold, and after being cooled and solidified, the plastic formed product is obtained.

The plastic mold consists of two parts: a movable mold and a fixed mold. The movable mold is mounted on the moving template of the injection molding machine, and the fixed mold is mounted on the fixed template of the injection molding machine. In the injection molding, the movable mold and the fixed mold close constitute a casting system and a cavity, and when the mold is opened, the movable mold and the fixed mold are separated to take out the plastic product.

Although the structure of the plastic mold may vary depending on the type and performance of the plastic, the shape and structure of the plastic product, and the type of the injection machine, the basic structure is uniform.

Plastic mold by function

Mainly consists of: pouring system, temperature control system, molded part system, exhaust system, guiding system, ejection system and so on. The gating system and the molded part are in direct contact with the plastic and vary with the plastic and the product. It is the most complicated and most varied part of the mold, and requires the highest degree of smoothness and precision.

1. Gating system:

It refers to the part of the flow channel before the plastic enters the cavity from the nozzle, including the main channel, cold material hole, shunt channel and gate.

2. Molded parts system:

It refers to various parts and components that make up the shape of the product, including dynamic molds, fixed molds and cavities (concave molds), cores (punches), and molded rods. The core forms the inner surface of the article and the cavity (female) forms the outer surface shape of the article. After clamping, the core and cavity form the cavity of the mold. According to the process and manufacturing requirements, sometimes the core and the die are made up of several pieces, sometimes made into a whole, and only the inserts are used in the parts that are easily damaged and difficult to process.

3. Temperature control system:

In order to meet the mold temperature requirements of the injection process, a temperature adjustment system is required to adjust the temperature of the mold. For injection molds for thermoplastics, the cooling system is primarily designed to cool the mold (the mold can also be heated). The common method of mold cooling is to open a cooling water channel in the mold, and use the circulating cooling water to remove the heat of the mold; the heating of the mold can be done by using hot water or hot oil in the cooling water, and can be installed inside and around the mold. Electric heating element.

4. Exhaust system:

In order to remove the gas generated by the melting of the air and plastic in the cavity during the injection molding process, the gas is formed on the surface of the product, and the surface of the product may form a gas mark (gas pattern), burnt, etc.; The gas system is usually a trough-shaped gas outlet opened in the mold to discharge the gas of the original cavity air and the melt.

5. Guidance system:

It is to ensure that the movable mold and the fixed mold can be accurately centered during mold clamping, and the guide member must be provided in the mold. In the injection mold, four sets of guide columns and guide sleeves are usually used to form the guide members, and sometimes the inner and outer tapered surfaces are respectively arranged on the movable mold and the fixed mold to assist the positioning.

6. Eject system:

Generally, it includes: thimble, front and rear ejector plate, thimble guide rod, thimble return spring, thimble plate locking screw and other parts. When the product is molded and cooled in the mold, the front and rear molds of the mold are separated and opened, and the plastic product and its conglomerate in the flow passage are pushed out or pulled out of the mold opening and flow path position by the pushing mechanism-the ejector pin under the push rod of the injection molding machine. In order to carry out the next injection molding work cycle.