The liquid silicone injection (injection) molding process can be roughly divided into the following six stages:

1. Mold Closing: The mold is closed in preparation for injection.

1. Injection: Inject liquid silicone rubber into the mold cavity.

1. Holding Pressure: Maintain a certain pressure to ensure the complete formation of the product.

1. Cooling: Allow the product to cool and set in the mold.

1. Mold Opening: Open the mold to prepare for product removal.

1. Product Removal: Remove the molded product from the mold.

During this process, the quality of liquid silicone injection is closely related to temperature, pressure, and time:

• Temperature Control: It is mainly regulated from three aspects: barrel temperature, nozzle temperature, and mold temperature. The nozzle temperature is usually slightly lower than the maximum barrel temperature to prevent the liquid silicone rubber from vulcanizing and blocking at the nozzle. The mold temperature includes three links: heating, heat preservation, and cooling. Its level depends on the vulcanization conditions of the liquid silicone rubber, the size and structure of the injection - molded part, performance requirements, and other process conditions, such as the thermal vulcanization temperature of the liquid silicone rubber, injection speed, injection pressure, and the time required for a single injection - molded part.

• Pressure Control: The pressure control during injection molding is divided into plasticizing pressure and injection pressure, both of which directly affect the quality of the injection - molded parts.

• Plasticizing Pressure: When a screw - type injection machine is used, the pressure that the molten material at the top of the screw withstands when the screw rotates and retreats is called plasticizing pressure, also known as back pressure. The magnitude of this pressure can be adjusted through the relief valve in the hydraulic system. Increasing the plasticizing pressure will enhance the shearing effect, thereby increasing the temperature of the thermosetting silicone rubber material, and vice versa.

• Injection Pressure: The injection pressure of a liquid silicone rubber injection machine is calculated based on the pressure exerted by the plunger or the top of the screw on the liquid silicone rubber. During the injection molding process, the role of the injection pressure is to overcome the flow resistance of the silicone rubber material flowing from the barrel to the cavity, provide the filling rate of the silicone rubber, and compact the silicone rubber.

There are three aspects to measure a good liquid silicone injection - molded part:

1. Appearance Quality of Liquid Silicone Injection - Molded Parts: Including integrity, color, and luster.

1. Accuracy of Dimensions and Relative Positions: That is, dimensional accuracy and position accuracy.

1. Mechanical, Chemical, Electrical Properties, etc. Corresponding to the Use: That is, functionality.

New technologies for liquid silicone rubber injection molding are not limited to: micro - injection molding, highly filled composite injection molding, water - assisted injection molding, combined use of various special injection molding processes, foam injection molding, mold technology, simulation technology, etc.