In the injection molding process, the pipe fitting mold often fails to fill completely. When the injection molding machine just started to work, due to the low temperature of the pipe mold, the heat loss of the PVC molten material is large, it is easy to produce early solidification, the cavity resistance is large, and the material cannot fill the cavity. This phenomenon is normal and temporary and will disappear automatically after several consecutive injections. If the PVC pipe fitting mold has not been completely filled, the following conditions should be considered and appropriately adjusted:

1. Due to the high heating temperature, hot bubbles will be generated. Excessive process temperature will cause the volatiles in the raw materials to evaporate, and will also cause the material in the PVC pipe fitting mold to partially decompose and generate bubbles.

2. The injection speed of the pipe fitting mold is too fast. The molding process of PVC injection products should use lower injection speed and higher injection pressure.

3. The gate is small or the cross-section of the runner is small, and the flow resistance is too large. Therefore, the cross-section of the gate and runner can be appropriately increased to reduce the melt flow resistance.

4. During the injection molding process of pipe fittings, it was found that the content of moisture or other volatile substances in the raw materials is too high, or the storage time of the raw materials is too long to absorb the moisture in the air. When purchasing raw materials, the volatile components in the raw materials should be strictly controlled. In periods or regions with high air humidity, the raw materials and auxiliary materials should not be stored for too long.

5. The surface gloss of PVC injection pipe fitting mold products is largely related to the fluidity of PVC materials. Therefore, improving the fluidity of materials is an important measure to improve product quality. Since the temperature of the molten material is low and the fluidity of the material is poor, the heating temperature of the material can be appropriately increased, especially the temperature at the nozzle.