Shell shortage, also known as lack of glue, insufficient filling, insufficient injection, incomplete plastic shell, etc., is the most common problem we encounter in plastic shell injection molding every day, which is usually manifested in the end of the molding area and the position of fine ribs. Compared with other defects, the debugging is simple, which can be solved by increasing the injection pressure, injection speed, injection position and other methods in the process, but sometimes other factors are not excluded.

Adjustment and improvement methods leading to the shortage of plastic shell materials

1. The setting of injection molding conditions is unreasonable. The injection pressure is too low, the injection speed is too slow, the injection position is too short, and the molding time is too short. Because the amount of glue required for the plastic shell is not enough, the plastic shell is not filled enough (adjust the value of each parameter appropriately).

2. Whether the injection molding machine has back pressure. If the injection molding machine has no back pressure, or the back pressure of the stored material is too small, the dissolved material is not evenly compacted to ensure uniformity and homogeneity, resulting in insufficient filling of the plastic shell (appropriately increase the back pressure).

3. Whether the heating ring of the barrel nozzle is damaged and whether the thermocouple is clamped improperly. If the heating ring does not reach the rated temperature, the nozzle will condense, and the resistance during melt injection filling is too large, resulting in insufficient filling of the plastic shell (replace the heating ring and tighten the thermocouple).

4. Check nozzle blockage by discharging empty bullets. If the nozzle is blocked by iron and the filling is unstable during production, the plastic shell is often accompanied by the phenomenon of more glue and less material (clean the nozzle in time).

5. Residual material in nozzles and intersections / drums and flanges. If there is material left behind the mold, the plastic shell will lack material due to insufficient pressure in the mold cavity during the injection filling process (solve the problem of material shortage in time).

6. The mold temperature is uneven or too low. If the temperature of the mold is too low, the solution will condense too early during filling and cannot be filled to the set position, resulting in insufficient plastic shell. (increasing the mold temperature and changing the series water circuit to parallel connection can also appropriately shorten the molding cycle).

7. For materials with poor fluidity, such as PC, PA, POM, etc., you can increase the diameter of the runner and gate on the mold, technically increase the temperature of the barrel, increase the mold temperature regulator, and add additives to the materials to improve the fluidity, so that the melt can quickly reach the set position in the mold cavity to avoid material shortage of the plastic shell (appropriately increase the mold temperature).