Have you satisfied yourself that the problem does not lie with the belt itself? ■

Well for starters the transition from the last idler to the tail pulley and the head pulley for that matter should be a 20 degree and there is a calculated distance to where that should be. The rule of thumb I use is 1 x BW (Belt Width) to the 20 degree and 1.5 x BW to the first 35 deg. So I would say that they are loading the belt much to close to the tail pulley to get the proper transiitioning required. But that may not be the reason that you are experiencing tracking problems.

I am not a believer in the pulleys being raised above the center rolls (half-troughed) - it is used to reduce the amount of transition required from the tail pulley to the first idler but there is a huge debate about this.

Never try to steer a belt by adjusting a pulley off of square to the belt. All pulleys need to be verified that they are square to the frame and parallel to each other. Then train the belt by adjusting roller frames only.

The loading of the product must be hitting at the center of the belt or it will cause the belt to mistrack off center.

How is the belt being tensioned? Has the required tension been calculated and properly applied?

I also move your post to a more related forum. ■

Hi there..

This topic has been thrashed to extremes in previous threads, so to avoid repetition, see what has been written..

In your case it looks like the designer has no experience, and the erector forgot to align the components.

Cheers

LSL Tekpro ■

I just noticed that you said ALL idlers were installed with a 2 degree tilt. That is just totally wrong.

I agree with Graham on this one.

You might want to have a read here.

https://forum.bulk-online.com/showthread.php?t=18199 ■

Two degree forward tilt is not the best way to long term tracking. This requires a stable friction between belt and roller. If you wet the wing surface of one side and have applied forward tilt , you will see misalignment.

The noted prior posting from Gary with the dissertation on tracking has two points of contention.

1. Bicycle Handle Bar effect - can be misleading since most handle bars bend back toward the rider. This geometry will cause mistracking. If you insist on using forward tilt the wind roll outer position must tilt toward the head not toward the tail.

2. This dissertation has not mentioned leveling the idler crossection. This must be level otherwise the belt will seek a new offset position favoring the lower point of gravity. Think about how we bank idlers to move them off center to negotiate a horizontal curve. You can induce better tracking by gradually elevating the vertical support legs a couple of mm at a time on the side where the belt is mistracking toward, given the load station is centered and idlers are properly set 90 degrees to belt travel. ■

Hi again..

If you drew a graph of training effect vs. roll angle to the belt, then once you get over about 4 degrees the steering effect gets erratic and of little use.

Normal tilt is up to 1 degree, but 2 degrees is still OK.

(You should see the geometry of the idler rolls for my horizontally curved conveyors.. thereafter you would not worry about 2 degrees.)

You must however have the belt troughing nicely down in the rolls to get good tracking. Therefore don't go 1/2 x trough depth at the transition, limit this to 1/3 x trough depth maximum.

Align the thing properly, load it centrally, nice 1/3rd transition, straight belt, good splice.. and it will track well.

(Gary agrees with me on this one...wow... no wonder it has finally stopped raining in Johannesburg...)

Cheers

LSL Tekpro ■