The concrete industry is one of the most challenging environments for linear motion products. High levels of fine dust are created when cutting concrete, causing a dirty, polluted environment that many systems would not be able to cope in. For one Belgian company, that made the choice of linear guides critical.
Koraton NV, a specialist in the production of vaults and structural elements in Belgium, places stringent demands on linear guides, with an overhead gantry system that works five days a week for 16 hours a day, moving a sawing machine back and forth to cut multiple concrete bars simultaneously. The application calls for heavy duty linear guides that can operate almost maintenance-free in an extremely harsh environment.
To meet this requirement, machine builder Rotsaert Machinebouw specified HDS2 heavy duty linear guide from HepcoMotion. Two 4m HDS2 linear guides are attached to a steel framework, and four Hepco through hole bearings are fitted to a carriage plate which holds the sawing machine. Pinion driven, HDS2 moves the sawing machine back and forth to cut the bars to size. The lengths vary from 0.5m to 3.5m long. HDS2 is available in one piece up to 4m long which neatly accommodates the required stroke length for this application, saving on assembly time.
The sawing machine is approximately 50kg in weight, so although the load is not particularly high, a heavy duty solution is required due to the rugged and harsh conditions. To reduce the dust, the concrete is cut using a wet-cutting process. The resulting slurry from the water and dust creates an extremely hostile environment. In a ball rail system for example, if particles of dirt and debris such as dust, find their way beyond the seals, or if they become damaged the internal ball bearing track will become jammed and motion will be impeded. This can result in catastrophic failure – meaning excessive downtime and a complete system change.
Hepco’s V guide system, however, has an inherent wiping action due to the geometry of the slide and bearing interface. This means that dust, dirt and debris is expelled from the running surface and the system works perfectly well in contaminated environments. This self-cleaning action is one of the key reasons why machine builders Rotsaert Machinebouw specified Hepco for this application. A family-run business, Rotsaert Machinebouw have 35 years experience in building prototypes, automation and metal constructions for various sectors and has come to rely on Hepco products for applications in harsh and challenging environments.
One key point with V technology is that only a small amount of lubrication is required to prevent wear of the slide, and in some instances it can also run dry. This was important for Koraton to avoid the grinding dust sticking to the lubrication and forming an abrasive paste. Cap wipers are used, providing constant lubrication to the contact faces, as well as providing effective sealing and protection, preventing ingress of debris.
Another key challenge is that the system is subject to significant vibration caused by the impact of the circular saw coming into contact with concrete; a heavy duty, solid material. Vibration can cause wear to the guide which can ultimately lead to premature failure. Hepco’s V guide technology ensures a linear contact between the bearings and the rail, which distributes the forces better, reducing the effects of the vibrations, leading to a longer life.
The system rigidity provided by Hepco’s V guide technology benefits this application as it rigidly guides the sawing machine along the track, ensuring resistance to deflection. This is particularly important for Koraton to ensure the concrete bars are accurately cut to length without any damage caused by deflection.
Compliance is also key here as the sawing machine is mounted to the HDS2 guides on a framework parallel to the ground. The guides need to perform on an un-machined surface and so must be tolerant of a degree of misalignment. The design of Hepco’s V bearing allows for the bearing to perform on uneven surfaces and cope with variances in the mounting surfaces.
Designed to handle the heaviest loads and the most demanding environments, Hepco’s HDS2 heavy duty slide system is well suited to this application. Having had numerous problems with its previous system not working properly and being a constant cause of maintenance work, Koraton is very satisfied with the longevity and reliability of Hepco’s HDS2 heavy duty linear guide. Robust and durable, after five years, the only ongoing maintenance Hepco’s HDS2 requires is to periodically check and update the grease within the cap wipers and the grease on the guides.