Home > Exhibition > Content

Common problems and solutions in the production of PET Preform

Jun 16, 2020



methods for troubleshooting

1.The bottom of the PET Preform is white

1. Insufficient hot runner temperature

2.Lack of material temperature


1.Enhanced insulation measures

2.Turn up the hot nozzle temperature

3.Raise the material temperature appropriately

4.To speed up the injection speed

5.Reduce the pressure

6.Cooling water velocity reduction


2.The PET Preform is opaque



1.Insufficient drying of  raw materials

2.Insufficient plasticization of raw materials

3. Excessive thickness or insufficient cooling of pp> bottle embryo wall

4.Mixed with other plastics

5.Material temperature is too low

1.Keep dry for more than 4 hours

2.Temperature rise of material

3.Increase the screw speed

4.Check whether the drying temperature is too low or the injection amount is not suitable. Make sure the material is dried at 165 degrees until the moisture content is less than 0.02%

5.Strengthen cooling and thicken the wall

3.The PET Preform changes from transparent to opaque


The demulsification temperature is too high

1.Reinforced cooling water

2.Extended cooling time

3.Change the injection time

4.There is a mist shadow on the side of the PET Preform

1.Pressure is too high

2.Bottom film gate hole eccentric

1.To reduce pressure

2.Fixed mold


5.The PET Preform is silver-streaked or yellowish

Plastic decomposition

1.Lower drying temperature and prolong drying time

2.Adjust injection speed

3.To lower temperature

4.Lower the hot tip temperature

6.The PET Preform has bubbles


Insufficient drying

1.Strengthen the dry

2.Increase the material temperature

3.Reduce the screw speed

7.There are irregular ring grooves in the PET Preform


Water vapor condenses in the core cavity


1.Enhanced workshop drying

2.Raise the cooling water temperature

3.Dry the mould

8.The PET Preform cracks at the sprue



1.The heat flow gate is different from the gate

2.Buckle the gate

3.The gate area is too hot


1.Fixed mold

2.Fixed gate

3.Extended cooling time

4. Increase infusion speed or injection time

5.Strengthen gate insulation

9.The mouth of the  PET Preformis not full or there are dissolute lines

1.The venting is not good

2.Injection of eccentric


1.Enlarged exhaust slot

2.Wash lip mould

3.Reduce the injection speed

4.Fix the sprue hole of die bottom


The  PET Preform has a thick edge and a thin edge



1.Poor mold manufacturing

2.Gate hole offset

3.Excessive injection pressure

4.Core displacement

1.Fixed mold

2.Improve the material temperature

3.Lower pressure

4.Die with high strength, high precision and adjustable core structure