{"id":2328,"date":"2021-11-15T11:19:38","date_gmt":"2021-11-15T03:19:38","guid":{"rendered":"http:\/\/www.moldedepreforma.com\/?p=2328"},"modified":"2021-11-15T11:19:38","modified_gmt":"2021-11-15T03:19:38","slug":"basic-pet-preform-injection-molding-troubleshooting","status":"publish","type":"post","link":"https:\/\/www.moldedepreforma.com\/index.php\/2021\/11\/15\/basic-pet-preform-injection-molding-troubleshooting\/","title":{"rendered":"Basic PET Preform Injection Molding Troubleshooting"},"content":{"rendered":"

Downtime is one of the disasters for any factory, especial for those people who are green hands. That’s why we list the\u00a0basic PET preform injection molding troubleshooting<\/strong>\u00a0here. 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.<\/p>\n

Above all, let’s learn the\u00a0PET preform injection molding basics<\/strong><\/em>\u00a0– kindly click it for learning that what is PET material and its characteristics and the PET preform injection molding process.<\/p>\n

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.<\/p>\n

1. PET Preform is Not So Transparent<\/strong><\/p>\n

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).<\/p>\n

b. Insufficient plasticization of PET materials – increase the heating temperature of barrel.<\/p>\n

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.<\/p>\n

2. PET Preform Becomes Opaque from Transparent<\/strong><\/p>\n

a. Higher mould temperature – improve the mould cooling or increase the cooling time.<\/p>\n

3. PET Preform Bubbles<\/strong><\/p>\n

a. Material PET was not dried enough – dry the PET material for enough time; or increasing the feeding temperature.<\/p>\n

4. Internal Shrinkage of the Preform Bottom<\/strong><\/p>\n

The major reason is bad cooling of cores, so the detail reasons and solutions could be:<\/p>\n

a. Excessive dirt of water cooling channel – cleaning the core cooling channel;<\/p>\n

b. Insufficient water pressure – raise water pressure to ensure the good cooling effect;<\/p>\n

c. The temperature of recycled cooling water is higher – adjust the chiller or others to improve it.<\/p>\n

5. Burn Mark of PET Preform<\/strong><\/p>\n

Like the fourth point, the main reason is the bad cooling of cavities, so it is similar by that, just add another solution:<\/p>\n

d. The injection nozzle temperature is too high – reduce the temperature of it.<\/p>\n

6. The Preform are Yellow<\/strong><\/p>\n

It is because of the higher temperature so that the PET material is oxidized, and the high temperature usually is from the following factors:<\/p>\n

a. Barrel temperature is much higher – reduce it slowly and test until the preforms are transparent;<\/p>\n

b. Mould temperature is much higher – check the cooling effect and improve it;<\/p>\n

c. The PET material stays in the barrel for long time – make it empty and improve the cycle time or operation;<\/p>\n

d. Over-dried PET material – do well in the material drying and change the material for new pet material injection molding.<\/p>\n<\/div><\/div>