Release Date : 2019/8/23 20:44:22 Click Volume : 4862
First, it must be dry before injection molding. Generally, it is hopper type drying 70~80°C/2h or tray drying 80~100°C/1h. For the drying of the tray, it should be noted that the thickness of the layer is generally not more than 50 mm. Tray drying is recommended. If there is foaming on the surface of the injected strip, or the strip is cut, and there is a cavity inside, or the surface of the product is scattered with silver, it can be determined that the TPE/TPR raw material has too much water content.
Second, try to use low temperature injection molding. Under the premise of ensuring the quality of plasticization, the extrusion temperature is reduced as much as possible, and the injection pressure and screw rotation speed are used to reduce the melt viscosity to achieve the purpose of improving fluidity. When the surface of the strip injected from the nozzle is smooth and bright, the plasticization quality is good. If the strip injected from the nozzle is very bright, it can be determined that the barrel temperature can also be lowered. Try to use low temperature injection molding to reduce cooling time and increase customer productivity.
Third, the upper parabolic temperature setting. The middle temperature of the screw is the highest, the feeding section is slightly lower, and the nozzle is slightly lower. Typical temperatures are set at 150-170 ° C (feed), 170-180 ° C (middle), 190-200 ° C (front), 180 ° C (nozzle). This temperature setting is only used as reference data. The specific temperature can be adjusted according to the specific physical properties of different TPE and TPR materials. If the content of the product is found to be bulging (the gas is contained inside), the gate is easily broken when the mold is released, and the adjustment can be made with reference to the second.
Fourth, the pressure holding pressure is as small as possible. Generally, the holding pressure is smaller than the injection pressure. The holding time can be determined by weighing the product, and the weight of the product is no longer increased, or the shrinkage mark accepted by the customer. If it is found that the gate is easy to break when demoulding, and the second can not be effective, it should be feasible to reduce the holding pressure.
5. If it is a few levels of injection, the speed is slow to fast. Because of this, the gas inside the mold is easily discharged. If there is gas inside the product (internal bulging), or there is a dent, the use of 诀窍2 is invalid, this method can be used to adjust.
