The production of rubber products by injection is generally carried out by several processes of preheating, plasticizing, injecting, vulcanizing and discharging.
1 Preheating, plasticizing
The barrel heat is heated by the barrel heating and the screw rotation, and the rubber material sent to the barrel is heated. When the rubber is plasticized to a certain extent, it has a certain fluidity.
When the rubber is plasticized to a certain extent, that is, it has a certain fluidity, it is pushed forward by the plunger, so that the rubber is forcibly injected into the closed hot mold through the nozzle, the flow passage, and the gate. In order to prevent scorching, the barrel should be kept at a low temperature, generally 70~80°Co. When the rubber passes through a small nozzle, the temperature of the rubber can rise above 120 °C due to frictional heat generation.
3 pressure forming vulcanization and pre-plastic feeding
After the model is filled with the rubber, the rubber is vulcanized under a certain model pressure and temperature; when vulcanized, the screw plasticizes the new rubber and deposits it into the barrel. Under the back pressure of the rubber compound, the plunger is pushed backwards until the barrel is filled with rubber to prepare for the next injection.
At the end of the vulcanization, the ejection mechanism ejects the product to complete the entire injection process. After demolding, the model is automatically closed, and the next batch of rubber can be injected and vulcanized. According to the process of heating plasticization→injection→hot pressing vulcanization→release molding, it is automatically cycled.