Working principle of liquid silicone injection machine

The working principle of liquid silicone injection machine is based on the physical properties and thermosetting reaction mechanism of liquid silicone (LSR), and efficient molding is achieved by precisely controlling material mixing, injection pressure, temperature and mold design. Its core process starts with the precise mixing of two-component liquid silicone (A glue and B glue). The raw materials are delivered to the mixing device in a 1:1 ratio through a synchronous metering system (such as a two-way pump or a synchronous single-way pump with a check valve), and color or functional additives may be added during this process. The mixed rubber is easy to flow due to its low viscosity, and it needs to be further homogenized and pushed to the injection unit with the help of a screw plasticizing system, while a sealing structure (such as a needle valve nozzle) prevents leakage.
During the injection stage, the machine injects the mixed rubber into the mold cavity preheated to 170200℃ at high pressure through a hydraulic or electric drive system. The mold design adopts a cold runner system or a hot runner system. The former controls the flow of the rubber through a needle valve to avoid premature curing, while the latter relies on precise mold temperature management to promote rapid vulcanization. Liquid silicone undergoes a platinum-catalyzed cross-linking reaction at high temperatures to form a three-dimensional network structure. This process significantly shortens the molding cycle. Precise control of the injection pressure and the holding pressure stage ensures that the material fully fills the mold cavity and compensates for the curing shrinkage, avoiding burrs and internal bubbles.
After curing, the mold is demolded by a pneumatic or mechanical ejection mechanism, and the product is post-processed by trimming, grinding, etc. to meet the final requirements. Throughout the process, the automated integration of equipment (such as the coordinated operation of the feeding system, temperature controller and vacuum device) ensures high precision and hygiene standards, which is especially suitable for medical, electronic and other fields with high cleanliness requirements.