Thermoset molding technology is widely used in the field of plastic molding. It utilizes the curing reaction of thermosetting plastics at high temperatures to produce plastic products with excellent performance. Thermoset molding is one of the most important technologies in this field, with its principles and operating steps determining the quality and production efficiency of the molded parts.
Material Plasticization
The injection moulding thermosetting plastics first requires the plasticization of the raw materials. The raw material is heated and mixed in the screw groove of the injection machine. By rotating the screw, the plastic advances from the feed port along the barrel. In this process, in addition to the heat from the barrel wall, the frictional heat generated by the screw rotation is also a key factor for heating and plasticizing the plastic. The thermosetting plastic is evenly mixed in this process and is converted into a more fluid molten state through friction and shear action.
Metering
After the plasticization of the thermosetting raw material is completed, the screw begins to rotate to push the molten plastic to the front end of the barrel. This process is also known as metering. The key to metering is to control the amount of material to be injected. The screw will retreat as it compresses the material until it reaches the set injection volume. Once the screw stops, the molten material is temporarily retained at the front end of the barrel, ready for the next injection step.
Injection Filling
In the injection filling stage, the plastic begins to be injected into the mold cavity under high pressure. At this time, the molten thermosetting plastic quickly flows into the mold cavity through the nozzle until it fills the entire cavity. The thermosetting plastic undergoes high-speed shear and temperature rise in this process, reaching an ideal plastic state. To ensure the completeness of mold filling, a certain injection pressure must be maintained until the mold is completely filled.
Curing Reaction
The thermosetting plastic continues to be heated in the mold, undergoing a curing reaction. The molecules of the resin begin to cross-link, forming a network structure, and the plastic also releases heat in this process. This curing reaction requires a certain amount of time to complete. During this process, the molecular structure of the plastic changes, thereby enhancing the strength and durability of the plastic.
Ejecting the Part
After curing is complete, the injection molding machine's movable mold plate begins to retreat, and the mold opens. The plastic part is ejected and removed by the ejection mechanism inside the mold. At this time, the pre-plasticized raw material for the next molding cycle is already prepared, and the entire process moves into the next cycle.
Thermoset molding technology not only improves production efficiency but also manufactures plastic products with excellent physical properties. In the thermosetting plastic injection molding process, precise operation and control are key to ensuring product quality. Keyplast provides high-quality injection molding raw materials and professional technical support to help you perform thermoset molding more efficiently, ensuring smooth production. For more information about thermoset molding, feel free to consult Keyplast.
