Coating `can double belt lives`

Applying a flexible fluoropolymer to drive and timing belts could double their working lives, and cut breakdowns, its developer claims. The coating, called Xylan 2020, was originally developed as a weatherstrip coating for the automotive industry, but its developer, Whitford Plastics, says that applying the material to the contact surface of a belt reduces friction, thus extending its life and decreasing wear.

Another characteristic of the coating is that it eliminates "stick-slip" or "fretting" - the tendency for a belt stretched tightly against a drive wheel to "stutter" or slip repeatedly when the drive motor is turned on. The process of sticking and slipping under pressure, generates heat and tears off tiny fragments of the belt. The debris collects at the contact surface and, as the belt turns, acts as an abrasive that wears the surface further.

In the case of toothed belts, the stick-slip effect can cause the teeth to snap off, increasing slippage, generating friction and heat, and possibly leading to a catastrophic belt failure.

Whitford claims that the waterborne coating can double the lives of drive belts in applications including conveyors, mixers, and packaging machines. The company adds that Xylan 2020 does not suffer from the disadvantages of some other coatings such as silicones which wear off quickly, thus losing their lubrication properties, and polyurethanes, which can be noisy.