Featured Tech tip: Calculation of the proper coefficient of friction for your tension brakes is critical to success

Tech tip: Calculation of the proper coefficient of friction for your tension brakes is critical to success

Air operated tension brakes utilize friction pads or similar device for delivering torque to an unwind shaft. These friction pads are usually available in a selection of friction coefficients. It is extremely important the proper coefficient of friction is used in your unwind application to properly control tension.

The torque requirement for your unwind is equal to:

• Minimum web tension X core outside diameter / 2 = Minimum torque requirement
• Maximum web tension X roll outside diameter / 2 = Maximum torque requirement

Your unwind brake should be the proper size to accommodate your required tension range (minimum to maximum) AND the friction pads must be the proper coefficient of friction to provide your required tension range.

If the brake you are currently using doesn’t give you proper tension control at the "low end" - try using friction pads with lower coefficient of friction. Conversely, if your unwind brake doesn’t supply enough torque at full roll - try using friction pads with higher coefficient of friction.

Written By: Jeff Damour, Sales Manager, Converter Accessory Corporation, Wind Gap, PA Phone - 800-433-2413