23 Jul 2024


Direct-drive linear modules are `ten times faster than ballscrews`

Copley Controls, the UK-based developer of the ServoTube tubular linear motors, has announced a range of direct-drive linear modules that combine its motors with bearing rails, position sensors, and cabling, making it easier for machine-builders to build high-throughput, multi-axis systems quickly and affordably. Copley asserts that the Servotube Module (shown below) is typically ten times faster than a traditional ballscrew and is more reliable.

The ready-made modules take care of mechanical alignments and offer predetermined performance characteristics, making them easy and quick to integrate single- and multi-axis applications. The load is mounted directly to the rugged forcer and several modules can be combined to create multi-axis systems with minimal design effort.

In many applications, the built-in position feedback eliminates the need for a linear encoder. The internal feedback is said to provide 12-micron repeatability and 350-micron absolute accuracy. For applications requiring higher accuracy, the modules can be supplied with 1-micron linear encoders.
The non-contact electromagnetic drive is said to offer a longer life than ballscrew or belt technologies, with no degradation in performance. The electromotive force is transferred directly to the forcer carriage without physical contact. Unlike ballscrews, there are no energy-storing components to introduce positioning errors caused by wind-up or backlash. The modules can be controlled by Copley’s own drives or by those from other manufacturers, such as Siemens, Parker or B&R.

There are two versions: an industrial drive with strokes of up to 1,323mm, producing peak forces of 312–1,860N and speeds of up to 8.7m/s; and a compact version for strokes of up to 825mm and speeds up to 10.8m/s. Both models are capable of 11–31G acceleration.