PET drying
A fault with the dryer will lead to hydrolysis of the material in the barrel of the machine. This will cause lowered I.V. of the material. Lowered I.V. is the major cause of bad quality in preforms and bottles. More than 60% of all PET processing related faults can be traced back to the dryer . Maintaining the dryer in optimum condition will allow the molding machine to perform at maximum efficiency and quality. Check the basics! Airflow - The most important parameter, there should be nothing causing a restriction in the process and regeneration air flow. Temperature - Process Temperature should be in the region of 145~170 º C Depending on the resin supplier and the drying time. Also check the Regeneration Temperature which should be around 200~230 º C depending on the maker. Time - Calculate (or measure) the time the material is in the hopper, this should be at least 3½ hours. Dewpoint - Correct dewpoint may vary according to the manufacturer of the dryer, consult the maker's...