Cross Machine Caliper Profile Control on High Speed Coated Packaging Lines
Cross-machine caliper control demands real-time induction calender profiling to maintain stiffness and prevent high-speed converting line jams.
Crepe Wrinkle Defect
Structural Failure
Discontinuities in the micro-fold pattern of tissue or specialty paper represent a failure in the mechanical bonding between the sheet and the drying cylinder. A crepe wrinkle defect appears when the fine ridges produced by the scraping blade collapse or bunch together into a coarse visible line. This condition indicates an imbalance between the adhesive strength of the coating and the impact force of the doctor blade.
Blade Operation
Blade vibration or poor cylinder surface conditions trigger the formation of these irregularities during the high-speed stripping of the web. The crepe wrinkle defect persists through the winding process because the thickened area creates a hard spot in the finished roll. Adjusting the blade angle and the chemical composition of the release agent helps prevent the sheet from sliding or bunching at the point of impact.
Skilled operators monitor the blade wear closely to avoid the onset of these structural flaws.
Product Integrity
Converters face challenges when processing rolls that contain these structural flaws. A crepe wrinkle defect reduces the localized softness of the paper and creates a point of weakness where the sheet may break under tension. Final product quality relies on a uniform creping frequency to ensure the expected bulk for the consumer.
When these creases are severe, the paper becomes unsuitable for embossing or printing because the surface is no longer uniform. This defect remains one of the primary causes of rejected lots in tissue mills.