Residence time is too long 1. raw materials in the barrel or blow in the channel, the change of material properties.
The 2. blow inside the barrel of a foreign body.
3. the heating line is loose and the heating temperature is unstable, which leads to the degradation of the material.
4. die temperature difference of temperature is big.
5. mould head internal hydraulic oil leakage, contact material cause performance change.
6., blow molding screw, barrel serious wear, raw materials can not be uniform melting.
7., the mold cooling water is bad, cause the mold whole temperature deviation is big.
8. the mold exhaust is bad, the air accumulates in the mold cavity interior, causes the scorch material.
9. residual grease or lubricant in mould, contact with high temperature raw material, cause burning material.
10. raw material quality is poor, impurities.
11. the machine parameter is confused and the temperature setting is not correct.