Sharing the same axes to provide 'unparalleled performance' while saving machine space, linear motion innovator Copley Motion Systems is pioneering the use of multiple linear motors, says the company.

The tubular linear motor, which was originally designed by Copley, is inherently well balanced because the symmetrical design eliminates attractive forces, making mechanical integration simpler. However, more importantly the ServoTube range of linear motors and actuators are the first to use an integrated position sensor. As a result, an external encoder strip is not required enabling two or more forcers to operate on the same magnetic rod.

This use of two multiple forcers makes the ServoTube motor very versatile. A dual forcer stage can provide independent control of both forcers, so that two independently controlled forcers can double productivity. With each motor controlled by its own drive amplifier, totally independent motion becomes possible. The forcers can travel in unison or in opposite directions, so for example one linear motor can be programmed to load parts while the other unloads them.

In a recent packaging machinery application, three ServoTube linear motors were used to independently reposition bottles on-the-fly as they were moved in batches of three between a labelling machine and a bottle capping machine with incompatible conveyor systems. The Y-axis repositioning was achieved by the three linear motors operating simultaneously, while bolted to a ServoTube X-axis that moved the bottles between the two machines at the same time. The increase in performance resulting from executing several operations in parallel was significant.

Another feature of the drive stage is that two forcers can be mounted on a single rod to double drive force. In fact, three forcers can even be used to triple drive force.

The efficient design of the ServoTube motor minimises heat dissipation, eliminating the need for forced air cooling. Whilst proper ventilation of the machine is essential, the elimination of forced cooling can further simplify machine design and save space.

The linear motor is available in 25mm and 38mm diameter rod models, with different coil configurations to meet the required force and speed of the application.

Both the ServoTube linear motor and the moving rod ServoTube linear actuator provide high speed out-of-the-box positioning when combined the Xenus digital servo amplifier or a compatible sinusoidal servo amplifier, says the company.

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