Special injection molding principle

Author: MULAN – Plastic Molding Manufacturer

One: Exhaust injection molding Exhaust injection molding: The main purpose of exhaust is to make the gas generated during the cooling and solidification of plastics have a chance to be discharged. If these gases cannot be discharged from the mold cavity, the product will be incomplete or bubbles will be generated. Principle of exhaust injection molding: When the injection volume reaches 80%-95%, stop the injection molding; open the mold about 0.1-0.2mm to exhaust the gas; close the mold again, and continue the injection molding process.

Advantages: The injection pressure used in exhaust injection molding is lower, and larger products can be injection molded with lower clamping force. Two: Water-assisted injection molding Water-assisted injection molding technology is an advanced injection molding technology that injects part of the melt into the cavity of the injection mold, and injects high-pressure water into the melt through equipment to form parts. Benefits: Due to the incompressibility of water, it squeezes the inner wall of the product into a cavity, and the water also acts as a rapid cooling.

Therefore, water-assisted injection molding has many incomparable advantages over gas-assisted injection molding. Water-assisted injection molding can produce thinner and more uniform cavity walls, and the surface of the inner wall of the flow channel is very smooth. Especially for workpieces with very thick walls, water-assisted injection molding will require less cooling time than gas-assisted molding. Three: Compression injection molding Compression injection molding is one of the advanced forms of traditional injection molding.

Principle: Compression injection molding first injects the molten material into the mold cavity, when the molten material enters the mold cavity. The mold opens a certain gap under a certain pressure; after the molten material fills the cavity, the injection mold is locked with high pressure to obtain the product. When molding, the screw no longer injects molten plastic into the mold cavity, but presses Lf on the plastic through the high-pressure lock mold to form the product. The product orientation of compression injection molding is small and the internal stress is low.

This method is especially suitable for molding products with small volume and high transparency requirements; advantages: it can increase the flow length ratio of injection molded parts, use smaller clamping force and injection pressure, reduce the internal stress of materials, and improve processing productivity.