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UDL, or Uniformly Distributed Load, needs to be considered while selecting rollers.

Rollers are an integral part of Roller Conveyors. Both Gravity Roller Conveyors and motorized roller conveyors are formed using rollers. Optimum roller selection is necessary to avoid undue events in the future.

If under-capacity rollers are selected, there is a chance the required life of the conveyor cannot be guaranteed. Higher capacity rollers, on the other hand, result in increased investment and affect ROI. For this reason, optimum roller selection is very necessary.

Roller conveyors are used for various applications such as conveying carton boxes, plastic crates, totes, drums of various sizes, intermediate containers, wooden as well as metallic pallets, heavy duty automobile components, and many more.

Here one should note that we are discussing conveyor rollers used in "Roller Conveyors" for conveying carton boxes, components, etc. These are called unit handling conveyors. Bulk handling conveyor rollers, which are used to make trough belt conveyors, are a separate discussion. Please read here about the difference between the two.

Gravity Roller Conveyors move the product by way of gravity from higher heights to lower heights. Since no motor is used in these conveyors, there is no electric or any other consumption. They work on the basis of gravitational force. Gravity roller conveyors are the most widely used conveyors all over the world.

Motorized Roller Conveyors move the product with a motor. Rollers have various options to run using power — they are run with sprockets, timing pulleys, O-grooves and poly-V pulleys. When controlled product speeds are required, motorized roller conveyors are used.

What the Selection of Conveyor Rollers Depends On

The selection of conveyor rollers plays a major role in designing a roller conveyor. The selection of conveyor rollers depends on:

Weight of the Component

The weight of the component plays an important role. The weight of the component should be distributed inside the container properly. If the weight in a box is uneven, the behavior of the conveyor changes. In such cases, the roller pitch plays an important role.

Load Carrying Capacity of Conveyor Rollers

What is so special about that? One has to understand that the load-carrying capacity of a roller is distributive and not concentric.

If you have to carry a jumbo bag pallet of 1 ton weight, it does not mean that the weight capacity of each roller should be 1 ton. If the size of the pallet is 1m x 1m, the load is on an area of 1 sqm. The rollers which are in that 1 sqm area will carry the load of 1 ton — this load is not on a single roller. If there are 10 rollers in this area, the load of 1 ton is divided across those 10 rollers.

It also means that if a roller with a length of 500mm is given a load-carrying capacity of 50kg, it implies that you can put a load on the full 500mm equally and at once — it is a distributive load. Putting the weight of 50kg on a small portion of the roller, say 100mm, is not allowed, as that is a concentric load.

The Loading & Unloading Conditions

The loading and unloading conditions should equally be given importance. A metallic component of 50kg can run smoothly on a roller conveyor, but if it is dropped from a height of even 50mm while loading, the roller may be damaged.

Material of Construction

The contact material of the rollers plays an important role in the selection of the material of construction.

In some chemical industries, the normal working conditions become humid, similar to a seashore environment, which affects the roller's working. When rollers are to be used in chemical industries, the compatibility of the roller material with the process material should be tested beforehand.

Working Temperature

Extreme conditions are always challenging. Extreme cold or extreme hot conditions may affect the working of bearings.

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