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Technical Note

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When two belts, cut from one slab, are being spliced together to make one long belt, consideration needs to be paid to which ends are spliced together.  Often times the belts will have a camber to them.  If you splice the wrong ends of the two belts you will not be able to make them track.  The belts need to be installed so that the camber runs in the same direction.  If you don't you will be able to track half, or one section, of the longer belt and not the other.  Let's say that piece A is cambered to the left, and piece B is cambered to the right.  You can adjust the conveyor to track piece A by pushing to the right.  But then piece B comes around and you are pushing it right, which is the way it's cambered, so it goes way right.  No matter which way you force the belt, you will be correcting one section, and causing the other section (s) to track worse.  The belt pieces need to be spliced such that the camber is all in the same direction, which can be tracked allowing the belt to train.  Look at FIGURE 1.  This shows a 72" slab slit into two 36" wide belts.  Ends 1 and 3 are the outside ends as the slab arrived from the factory.  Ends 2 and 4 are on the core.  You need to either splice ends 1 and 3, or ends 2 and 4 together to insure proper tracking and trainability.

There are several reasons that long belts cut from long slabs have a camber.

1.  Non-uniform belt thickness.  This is caused by rubber volume being pushed out the edge of the belt during curing.  This happens to any and all belts during the manufacturing process and usually doesn't pose a problem.  It will cause greater problems the thicker the belt covers are.

2.  Dull slitter knives on the inside or outside cut, compared to the other knives.  This occurs when multiple slits are being preformed during on pass across the slitter.

3.  Unequal tension at wind up.  This is prevalent when using multiple windups, especially if the wind-up (s) are being used to pull the belt through the slitter.

4.  Moisture absorption.  This is more prevalent in belts with a nylon warp, especially if it is stored on it's edge on a concrete floor.  DO NOT STORE or SHIP ANY ROLL ON EDGE!

Click on Drawing to enlarge
FIGURE 1