We have a HR420 belt, 450mm wide that "cups" on the return run instead of sitting flat causing tracking of the belt to be only influenced by the edges of the belt. I spoke with someone about this "cupping" issue who suggested that it may be a result of poor quality nylon.

Matt Hunter ■

There are several reasons a belt can cup:

1. Exceeding the maximum rated trough angle of the belt.

2. Over-tensioning of the conveyor belt.

3. Heat

4. Chemicals that attack the belt that may be present in the conveyed product. (Cupping can occur up or down depending on the chemical)

5. The ratio of the top cover to the bottom cover is too great. As the belt ages, the rubber shrinks. If one cover is much greater than the other it will shrink more. ■