Downtime is one of the disasters for any factory, especial for those people who are green hands. That's why we list the basic PET preform injection molding troubleshooting here. Hope it could help you to achieve the efficient PET preform injection molding, reduce your downtime as you could quickly find the reasons and solutions.
Above all, let's learn the PET preform injection molding basics - kindly click it for learning that what is PET material and its characteristics and the PET preform injection molding process.
If you know the basic information of PET and PET preform injection molding, well, that's nice. Check the following notes of PET transparent preform injection molding defects and their solutions.
1. PET Preform is Not So Transparent
a. Material PET was not dried enough - dry the PET material for enough time (usually 4 to 6 hours) at the right conditions. The ideal moisture content of PET after drying is about 10 to 40 ppm (+/- 10 ppm).
b. Insufficient plasticization of PET materials - increase the heating temperature of barrel.
c. PET material is mixed with other material - check the PET material with the supplier and change the material; keep the room clear for PET material storing.
2. PET Preform Becomes Opaque from Transparent
a. Higher mould temperature - improve the mould cooling or increase the cooling time.
3. PET Preform Bubbles
a. Material PET was not dried enough - dry the PET material for enough time; or increasing the feeding temperature.
4. Internal Shrinkage of the Preform Bottom
The major reason is bad cooling of cores, so the detail reasons and solutions could be:
a. Excessive dirt of water cooling channel - cleaning the core cooling channel;
b. Insufficient water pressure - raise water pressure to ensure the good cooling effect;
c. The temperature of recycled cooling water is higher - adjust the chiller or others to improve it.
5. Burn Mark of PET Preform
Like the fourth point, the main reason is the bad cooling of cavities, so it is similar by that, just add another solution:
d. The injection nozzle temperature is too high - reduce the temperature of it.
6. The Preform are Yellow
It is because of the higher temperature so that the PET material is oxidized, and the high temperature usually is from the following factors:
a. Barrel temperature is much higher - reduce it slowly and test until the preforms are transparent;
b. Mould temperature is much higher - check the cooling effect and improve it;
c. The PET material stays in the barrel for long time - make it empty and improve the cycle time or operation;
d. Over-dried PET material - do well in the material drying and change the material for new pet material injection molding.
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There are so much different PET preform injection molding defects that cannot be listed here totally, so if you'd like to learn more or solve your PET preform molding problems what you have been troubled for a time, kindly contact us now, our expert team is here for technical supporting too, not only for providing Plastic Mould.
