Stokman conveyor rollers: production and materials

Our conveyor rollers are made-to-measure, which is why the dimensions and materials vary from one project to the next. We guarantee Stokman quality on every project because we only work with high-quality and wear-resistant materials. In this blog, we tell you more about the materials we work with and our production process. For example, did you know that our conveyor rollers are made in our own factory in Raamsdonksveer? You can read more about our materials, parts and automation here.

Materials used for Stokman conveyor rollers

Stokman quality means that as far as possible we match the construction of our rollers to the actual application they will be used for, taking into account not only the loads on the rollers but also the environmental factors where the rollers will be used. Although unfortunately we cannot break the laws of physics, we do make our conveyor rollers as resistant as possible to those factors. Limiting the deflection of a roller is very important for maximising its lifespan for various reasons such as vibration and imbalance.

The longer the roller or the higher the load on it, the more the roller will be deflected. That’s why we investigate the best choice for each roller in order to limit deflection as far as possible. We have two options for reducing deflection: increasing the diameter of the roller and/or axle or increasing the wall thickness of the tube. Increasing the diameter of the axle or roller element has a greater effect on stiffness than increasing the wall thickness. A greater wall thickness is usually chosen when the existing roller configuration at a particular location is not suitable for the loads there, but the roller does need to be stronger. Increasing the wall thickness is therefore the option chosen when a roller has to have a specific diameter or cannot be made larger due to lack of space. Our experts will be pleased to advise you.

Composition of conveyor rollers at Stokman

Conveyor rollers consist of a round tube with a welded-on bearing cartridge on either side, one axle, two bearings and a seal on both sides of each bearing. The various parts are put together from semi-manufactures, both from external suppliers and manufactured in our own factory. Assembly always takes place in our own factory.

The composition of our conveyor rollers always starts in our pre-processing centre. Here the tubes for the roller sleeve are sawn to the correct length and roughly machined. Our unique cast steel bearing cartridges are machined to the correct dimensions here. We have automated this process through the combination of a robot and CNC lathe. The roller axles are also sawn to length and machined to the correct dimensions. Both the seals and the bearings are come from external suppliers. The seals are always made to measure for our conveyor rollers. The bearings are manufactured and delivered according to the same standard worldwide.

Importance of bearings and seals in conveyor rollers

Two essential factors in a conveyor roller are the bearings and their seals. Each roller has two bearings, one on each side. However, if one of the bearings breaks down, the entire roller is immediately unusable. The bearings are therefore essential. That’s why Stokman only uses bearings of the highest quality.

As we have seen, the lifespan of the bearings is of the utmost importance for the lifespan of the entire roller. The seals protect the bearings and prevent water and dirt from penetrating. Water negatively affects the grease in the bearings; most rollers are therefore manufactured so that they do not need to be re-lubricated. Stokman mainly supplies rollers which are lubricated for their entire lifespan and are therefore maintenance free. These rollers only need to be replaced if they are damaged.

Insufficient lubrication causes damage to the bearings, resulting in a shorter lifespan of the roller. Dirt such as grains of sand or dust can also seriously damage a bearing, so it is essential that they are prevented from entering the bearing.

In all rollers, the bearings are already lubricated with special grease during production – enough for their entire lifespans. For special and extremely heavy-duty applications, it is possible to fit an additional lubrication device so that the bearings can be re-lubricated.

Automated production of roller elements for conveyor rollers

We put together the various roller components from the pre-processing centre to create the roller element. This consists of the tube and two bearing cartridges, along with the rotating part of the roller. These parts are automatically assembled by a welding robot. From the welding robot, the rollers are directly transported to the roller assembly machine. Here, the axle is inserted into the roller element and the pre-lubricated bearings are simultaneously pressed into the roller element. The bearings are then secured to the axle with locking pins and the seals are pressed onto the shaft.

The roller assembly machine then causes each roller to make a certain number of revolutions in order to properly distribute the grease inside the bearing and measure the roundness of the roller. This allows us to check that the roller will not deviate and to monitor the quality of our conveyor rollers. The roller itself is now ready for any finishing operations.

Finishing and lining conveyor rollers

Our conveyor rollers are available in different versions and as such they vary from one project to the next. When the roller is ready, it can undergo preservation treatment. We can paint the rollers in any RAL colour on our own paint spray line if required. Depending on the application, rollers can also be provided with different types of lining, such as buffer or support rings, PU or rubber lining.

Interested in the available options? Take a look at our configurator, which allows you to easily put together a conveyor roller based on your own specifications. We’ll send you a personal offer within 2 days! Do you have any other questions? Please contact us.