Motors simplify linear stage integration

A new type of modular linear drive unit with integrated position sensing can dramatically simplify the building of gantry and XYZ handling systems.
A new type of modular linear drive unit with integrated position sensing can dramatically simplify the building of gantry and XYZ handling systems. Using new IP67 rated industrial linear motor technology, linear stages can be bolted together in minutes to produce a rugged multi-axis configuration. Compared to traditional ballscrew-based linear stages, a ServoTube-based linear stage is much simpler, consisting of a single off-the-shelf unit with only two parts, the forcer (the coils) and the thrust rod (permanent magnets).

Because direct drive actuation is used, a gearhead, servomotor and ballscrew do not have to be aligned and integrated, saving valuable engineering time.

Backlash between a screw and nut and gearhead teeth are avoided using tubular direct drive technology, resulting in an excellent repeatability of just 12 microns.

Eliminating the mechanical drive train also dramatically improves speed to 10m/s, which is more comparable to belt drives, but delivering a more dynamic response reliably and with higher accuracy.

External position encoders require precise alignment, extra wiring and mounting area, occupying valuable machine space.

By using an in-built position sensor, ServoTube mechanical integration is simplified, this also allows the IP67 rated system to be used in a dirty environment such as a bottling plant or food slicing machinery.

Saving space is another benefit of tubular direct drive technology.

Machine builders may find that they have to compromise on their design to accommodate a servomotor.

For example, an XY system of 1m2 could require an additional 20mm for the servomotor and gearhead.

Whether affecting the external footprint or the internal operating space of the machine, eliminating this overhead is a clear advantage.

Large air gaps between the forcer and the thrust rod further simplify machine integration compared to some alternative tubular linear motors.

Alternatively, load-bearing X and Y axes can be built from pre-assembled ServoTube modules that typically use a single rail linear slide for support.

The ServoTube's rugged aluminium extrusion has DIN standard T-slots so that a load can be mounted directly onto the forcer.

Similarly, a Z-axis actuator can be bolted perpendicularly onto a Z-axis for instant configuration.

Finally, linear gantry and handling systems require maintenance - whether inside a machine or easily accessible, a production line must be halted for lubrication and part replacement.

The ServoTube requires no lubrication and a typical configuration is non-contact so it will not wear like gearheads and ballscrews.

The only maintenance that may be required is the lubrication of any external bearings added to improve radial load handling.

In addition to traditional moving forcer configurations, the ServoTube is also manufactured in a revolutionary moving rod configuration called the ServoTube actuator.

Often preferred for a Z-axis, the moving rod actuator uses a long life polymer bearing that requires no lubrication.

The reduction in engineering time resulting from the use of modular motor and actuator components has been well received by machine builders and system integrators worldwide.

ServoTube systems can be operated using standard sinusoidal drives, including their own range of drives such as the Xenus drive, which is ideally matched to ServoTube operation and provides 'plug and play' multi-axis operation using CANOpen.

* About Copley Controls - Copley Controls Corporation is a worldwide leader in high power amplifiers and high performance motion solutions for OEMs in the semiconductor, medical, pharmaceutical and automated assembly/inspection industries.

Headquartered in the USA with a division in England (Copley Motion Systems), Copley Controls has 20 years of experience in OEM partnerships.

Our global commitment is backed with sales offices and local technical support in the US, Europe and Asia.