The purpose of Kerkote® TFE coating is to supply a more even distribution of lubricant than is normally found when using standard self-lubricating plastics on steel. The wear life, coefficient of friction and resulting torque to drive a lead screw assembly are highly governed by the ability of the engineered plastic to supply sufficient lubrication to the nut/screw interface.The inability of the internal lubricating agents in some plastics to consistently migrate to the surface may result in erratic drag torques and unpredictable wear.

Kerkote TFE coating the entire screw surface results in an extremely even lubrication distribution. Test results indicate system torque requirements to be consistently low with little or no change in required frictional driving torque, even with changes in motor R.P.M.

Kerk has developed a custom composition Kerkote TFE specifically for our lead screw and nut materials. It is applied in Kerk’s facilities using an automated process. The uniform coating provides extended nut life and smooth operation with little additional cost.

HANDLING

Lubrication to the nut/screw interface occurs by the nut picking up Kerkote TFE particles from the coating as well as from the migration of the internal lubricant within the plastic nut. Although care is taken to ensure that chips and voids do not occur in the coating, small voids have been shown to have little effect on system performance. The lubricant, although solid, has some "spreading" ability as in fluid lubricants. When machining for bearing ends, soft fixturing is recommended.

Kerkote TFE coated screws provide the maximum level of self-lubrication and should NOT be additionally lubricated or used in environments where oils or other lubricant contamination is possible.