ONLINE WET FILM THICKNESS MEASUREMENT (WFM™)

DJH Designs Wet Film Measurement (WFM™) brings a new capability to paint line coater setup, providing accurate Wet Film Thickness (WFT) on the coater roll and the strip and predicting Dry Film Thickness (DFT) on the strip before painting commences.

Measuring wet film thickness on the coater before painting commences requires advanced coating model algorithms that account for several factors.

WFT measurements account for the following:
• Paint transfer efficiency between the coater roll and the strip – leakage is paint that does not end up on the strip
• Compensation for coating roll and coater roll bearing electricity
• Compensation for the ribbing (roping) of the paint that occurs on the coater roll, especially before coating commences
• Compensation for the difference in wet paint thickness between ‘before’ and ‘during’ painting

WFM™ is unsuitable if heavy ribbing on the coater roll becomes evident on the strip.

SIMPLE PRINCIPLE OF OPERATION

WFM™ uses an intrinsically safe confocal sensor to measure the position of the wet paint surface on the coater roll and then again the position of the coater roll’s surface at the same location. A pair of narrow, soft, and fully automated wipers on either side of the sensor wipe the paint off the roll to expose the roll’s surface. As the instrument measures the actual position of the surfaces, there is no need for calibration.

DJH Designs has patented the use of the measurement sensors above the rolls in a paint line coater.

WFM™ is the only system that measures WFT before painting commences, ensuring your product is in specification from the first meter of strip.