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Q

PET drying 0.005% red line

A

The moisture red line for PET sheet is at the 50 ppm level rather than the percent level; hydrolytic viscosity reduction is irreversible, and drying is the first lifeline of sheet quality; after confirming effectiveness, solidify the parameters and practices into the work instruction to prevent r...

Material Drying PET；drying；0.005%；50ppm；hydrolysis；IV

Q

PET bottle high haze exceeding standard

A

Haze is the quantitative indicator for transparent PET products; establishing linkage between per-batch haze testing and process records can quickly locate the root cause of exceeding the standard.; after confirming effectiveness, solidify the parameters and practices into the work instruction to...

Material Drying PET；bottle；haze；transparency；crystallization；testing

Q

PET mold temperature too low causing condensation

A

Condensation foggy spots are a typical manifestation of imbalance between mold temperature and environmental humidity; mold temperature is not the lower the better—it must be above the dew point to ensure surface replication quality.; after confirming effectiveness, solidify the parameters and pr...

Material Drying PET；bottle blowing；condensation；mold temperature；dew point；foggy spots

Q

Improper PET drying process

A

PET drying must use dehumidification rather than ordinary hot air; the three elements of dew point, temperature, and time are indispensable, and preventing secondary moisture absorption after drying is equally critical.; after confirming effectiveness, solidify the parameters and practices into t...

Material Drying PET；drying；dehumidification；dew point；moisture content；moisture absorption

Q

Pitting and white haze inside PET bottles (unclean air source)

A

Bottle interior contamination points directly to compressed air quality; food-grade bottle blowing requires a clean air source, and the inspection and replacement cycle of the filtration system must be included in the daily maintenance plan.; after confirming effectiveness, solidify the parameter...

Material Drying PET；bottle blowing；pits；white haze；compressed air；filtration

Q

PET Bottle Body White Haze (Hydrolysis Type)

A

Hydrolysis-type white haze is often accompanied by embrittlement and is a material defect rather than a pure process problem; controlling moisture from the preform storage stage is the most economical, and damped preforms are not recommended to go online directly.

Material Drying PET; bottle blowing; white haze; hydrolysis; damped; storage

Q

PET Preform Excessive IV Value Drop

A

IV is the fundamental indicator of PET bottle mechanical properties, and hydrolysis and thermal degradation are the two main causes of IV drop; drying and temperature control work together, and IV testing should be included in daily quality control.

Material Drying PET; IV; intrinsic viscosity; hydrolysis; thermal degradation; molecular weight

Q

PET Preform Bubbles (Insufficient Drying)

A

Preform bubbles are almost all related to moisture management, and qualified drying is the primary prerequisite; bubbled preforms will inevitably be stretched thin during blowing, so they should be rejected online and the drying records traced, and after confirming the measures are effective, sol...

Material Drying PET; preform; bubble; drying; moisture content; hydrolysis

Q

PET Preform Re-Moistening After Drying

A

Preventing re-moistening = the second half of drying.

Material Drying PET; drying; re-moistening; sealing; conveying

Q

PET Preform Bubbles

A

Bubbles = water or vacuum.

Material Drying PET; preform; bubble; drying; holding pressure

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