TPE,TPR injection molding process tips

First, the surface of the products must be dried before injection molding if the requirements are strict. Generally, it is 70~80℃/2h for hopper drying or 80~100℃/1h for pallet drying, it should be noted that the thickness of material layer is generally not more than 50mm. Tray drying is recommended. If the surface of the injection molding strip has blistering, or cut open the strip and find that there are hollows inside, or find that the surface of the product and scattered silver wire, it can be determined that the TPE/TPR raw materials contain too much moisture.

Second, try to use low-temperature injection molding. In the premise of ensuring the quality of plasticization, try to reduce the extrusion temperature, and the use of increased injection pressure and screw speed to reduce the viscosity of the melt, to improve the purpose of fluidity. When the surface of the material injected from the nozzle is smooth and shiny, it can be determined that the plasticization quality is good. If the strip injected from the nozzle is very bright, it can be determined that the barrel temperature can be reduced. Try to use low temperature injection, can reduce the cooling time, so as to improve the customer's production efficiency.

Third, the upper parabolic temperature setting. The temperature is highest in the middle zone of the screw, slightly lower in the filling section and slightly lower in the nozzle. Typical temperature settings are 150~170℃ (feeding), 170~180℃ (middle), 190~200℃ (front), 180℃ (nozzle). This temperature setting is only for reference, the specific temperature can be adjusted according to the specific physical properties of different TPE,TPR materials. If you find that the content of the product bulges (gas is wrapped inside) and the gate is easy to break when demoulding, you can refer to trick two to make adjustments.

Fourth, the holding pressure should be as small as possible. Generally, the holding pressure should be smaller than the injection pressure, and the holding time can be determined by weighing the product, and the weight of the product should not increase anymore, or the shrinkage mark accepted by the customer should be used. If it is found that the gate is easy to break during demoulding, and the trick two does not work, then it should be feasible to reduce the holding pressure.

Fifth, if it is several levels of injection, the speed should be from slow to fast. Because of this, the gas inside the mold can be discharged easily. If there is gas inside the product (internal bulging) or there is dent, this method can be used to adjust the product if trick 2 is not effective.