Belt Conveyor Tracking

Belt Conveyor Tracking is imperative for the smooth operation of a belt conveyor unit. There are a number of things to consider in regards to belt conveyor tracking. Most tracking issues can be eliminated from the start with the proper design considerations. Once the belt conveyor is installed onsite there are also a few basic steps to be undertaken to make sure the belt tracks nicely.

Design Considerations

Rollers Design

All drive rollers, as well as idler rollers need to be crowned to allow belt conveyor tracking. Most of our rollers are about 1mm bigger in the centre and tapered towards the outside. All Robotunits rollers are also made from steel with large wall thicknesses to guarantee that rollers will not bend when tensioning the belt. Bending of a roller would offset the crowning and create all sorts of belt tracking issues.

Aspect Ratio

A belt conveyor should be at least twice as long as it is wide to have a minimum ratio of 2:1. Anything lower makes belt conveyor tracking very hard. Here at Robotunits we generally keep to these ratios. There are a few scenarios when we can go a little below this ratio without the need for a tracking strip.

Tracking Strips

Should a ratio below 2:1 be required we design the belt with a tracking strip. This is a PVC strip bonded to the underside of the belt. The rollers have the relating groove turned into them. This will guarantee belt tracking. It has to be said that the belt should track on it’s own as much as possible without relying on the tracking strip. If it doesn’t then the constant side force applied to the tracking strip will eventually tear it of. So even with a tracking strip a belt conveyor needs to be set up correctly to make sure it runs smoothly.

Conveyor Belt Tensioning

The manufacturer of the conveyor belts specifies certain tensioning criteria to maximize efficiency. Generally a belt needs to be stretched by about 0.3%. This can vary slightly depending on the belt material. The belt stretching is needed to ensure that the drive roller cannot slip and also to ensure belt conveyor tracking.

Direction of Travel

A belt conveyor should generally be run in a “pulling” fashion. This means that the belt travels from the idle roller towards the drive roller. This is mainly to eliminate roller slippage but also greatly influences tracking. It is much easier to track a belt conveyor if run in a “pulling” rather then a “pushing” fashion.

Onsite Setup and Maintenance

Generally a belt conveyor is tracked from the idler roller end. All Robotunits conveyors have adjusting screws on each side of the idler roller. These are used to tension the belt and also to fine-tune tracking. Should a belt wander to one side simply tension the belt on that side a little bit more. A small adjustment often makes a large difference so start with quarter turns. Do this while the conveyor is running. Allow the belt to settle in for a while and readjust accordingly. There are further details in the conveyor manual supplied with each of our conveyors.

Maintenance

Please check your conveyors at least once a week to make sure the belt conveyor tracking is still maintained. It will guarantee a smooth and trouble free operation of your conveyor unit.

PDF of Belt Conveyor Tracking from the Robotunits Operations Manual.

Belt Conveyor Tracking

Extract from the Robotunits Conveyor Manual describing the belt conveyor tracking procedure.