Beyond these resources, manufacturers are available to provide technical support at the beginning of the project, verifying that the customer has designed the compressed air system appropriate to their needs and saving unnecessary worries. Depending on the size and complexity of the project, manufacturers can even provide local assistance, as well as collaborate to ensure the compliance of the installation.

Within the automation market, there are many applications for high loads, where the size of a single profile and bearing arrangement would be too large and expensive. Due to this, the idea of ​​the project was to design a cost-effective, dynamic, easy-to-install and high-cost guide unit. The typical applications are the use as Y axis in a multi-axis manipulation system (see the basic requirements of the system: stroke, load, moments).

Many designers have achieved a high load capacity using two electromechanical guide units in parallel. The distance between the two bearing units considerably increases the ability of the system to withstand higher torques. Although it offers a high level of flexibility to the designer, this solution is twice as expensive, and it is not easy to predict the useful life of the system.

The designer must be responsible for establishing the layout for optimal performance, as well as adding the additional cost of trying to align the components in a very rigid machine structure, and build the custom coupling plates, drive axes, etc. The fabric selected for the guide must allow loads in all the cardinal directions, as well as offer a long lifetime of the entire system, with or without predetermined maintenance. The modular physical assemblies are available to allow the combination of two individual electromechanical axes, but there is still the problem of calculating the final performance, accuracy and useful life.

Festo thought to offer the machinery manufacturers a unique combined shaft solution, with a more extensive individual profile and with several guide rails for high load applications (EGC type "heavy load" or EGCHD, see Fig. 3). Although this seemed like a simple task, in reality, developing a solution like that has been more difficult than was initially believed, and some useful notions have been extracted for design engineers.

Initial designs required a concept based on a very rigid aluminum barrel vault profile, two guide rails mounted precisely and rigidly, as far apart as possible, as well as the ball cage bearing cartridges, which had been tested until now. The design process lasted more than two years, and several bearing systems from different manufacturers were tested.

To maintain the service life of the bearing on the double bearing shaft, the tolerances were carefully defined for the contact surfaces of the profile with the guide rail of the linear bearing. It was determined that to offer a high-performance guide system, the aluminum support profile should be firm, rigid and should be manufactured accurately. To guarantee the useful life of the system, the axis should be valid for lengths of up to 9 m and installed with a parallelism of ± 0.05 mm and a deviation of the flatness of less than 0.2 mm.

Because the extrusion process had to be carried out with different manufacturers, it was decided to use a profile with the internal arc principle to provide it with the rigidity and tolerances necessary for the shaft. The problem is that you could not get a sufficiently flat surface for mounting the bearing.