Possible causes are analyzed:
1. The cylinder pressure is not enough, the normal working pressure should be 5bar.
2. Excessive injection molding
3. The temperature of the hot nozzle is too low, the four-gas valve sealing ring is worn and leaked, and the valve pin is worn
4. After the valve pin sleeve is worn and the rubber leakage is carbonized, the valve pin movement is not in place, the size of the mold is not accurate enough, and the mouth temperature is too low
