Adverse factors of plastic material and injection mold are in the following:
- The plastic melt is provided with high flow viscosity, resulting in poor flow and filling capacity.
- The plastic melt has poor plasticity, excessively low temperature for plastication and unbalanced melt temperature, which altogether result in the poor melt fluidity.
- Mold temperature is overlow or unbalanced, temperature of some parts is too low and temperature of melt injected into the cavity drops too fast.
- The flow of melt in the mold is too long or too complicated, the resistance against filling is large and the filling is not smooth, even resulting instagnation.
- Temperature of nozzle is too low and the cold-slug well of feed system is improperly set, resulting in jam and stagnation when the front cold material of melt enters the cavity.
- During the filling, molds are not sufficiently aired and the gas has not been discharged in time, thereby resulting in the expansion of filling resistance.
- Use plastics with low viscosity and sound fluidity or adjust prescription of plastics and reduce viscosity of melt.
- Improve barrel temperature, increase injection pressure, raise melt temperature to reduce viscosity, and improve plastication quality
- Improve mold temperature, and uniformity thereof, raise nozzle temperature and properly set cold-slug well.
- Increase dimension of the runner and gate and properly set gate position to avoid overlong flow during filling and overlarge loss of pressure when the melt enters cavity.
- Properly design mold exhausting scheme and change number of position of gate as well as position of parting line when necessary to achieve sound exhausting effect.