Low-cost positioners don't compromise on accuracy

Edited by the Engineeringtalk editorial team Apr 30, 2007

Economy positioners combine a rugged steel body with an integrated precision ball screw and bearing guide.

The 402/403XE series of economy positioners from Micromech combine a rugged steel body construction with an integrated precision ball screw and bearing guide producing a highly accurate, cost effective device ideal for applications in the hard disk, semiconductor, medical, machine building and as well as many other industries.

To achieve good accuracy the positioner uses a gothic arch configuration with four points of contact for each ball in the bearing set to assure smooth motion while achieving high precision capabilities.

It employs an integrated precision screw and guide, the bearing provides a low profile, high accuracy, smooth motion, and robust 'adjustment free' design over the life of the actuator The designers have chosen a precision ball screw drive train for smooth motion with high accuracy and high mechanical efficiency.

The rigid steel U-channel body provides structural rigidity for minimal deflection and is significantly stiffer than most aluminium body positioners.

This also means savings from reduced support structure can be realised.

Their low profile design is the result of using the highly integrated ball screw and guide bearing which allows for a greatly reduced overall height when compared with traditional stacking of a bearing and screw assembly, and so a more compact footprint.

Flexibility in limit switch options allows the customer to chose between a complete limit switch kit assembly and a standard limit switch kit mounted on the side of the tables.

This flexibility is further extended with NPN, PNP, normally open, and normally closed limit options.

With this unmatched design no pinch points exist between the limit sensors and target.

The limit sensor kit design allows the limits to be adjustable along the travel length of the positioner they are easily connected with fewer cables to manage in an aesthetically pleasing manner.

The limit/home switch installed is a Hall effect sensor tripped by a magnet located in a housing attached to the carriage.

On the switch body is an LED to indicate activation, normally open, normally closed, current sinking and current sourcing variations are selectable with the product.

Normally open sensors are typically used for home and normally closed are typically used for limits.

With a current sinking sensor, the output lead provides a path to ground when activated, and with a current sourcing sensor, the output lead provides a positive voltage potential relative to ground.

The 402/403XE have flexible motor mounting options so that a variety of motor drives can be fitted including servo and stepper motors.

With standard options for the Nema 17, Nema 16, Nema 23 these actuators allows the user to select the motor of their choice without being restricted to one model.

To further customise the application solution they can be ordered ready to mount most other manufacturers' motors as well.

For added protection from contamination falling into the bearing system and drive train, an optional hard clear anodised cover is available.

This will bring the positioner to an IP20 rating and prevent large particles from entering and damaging the screw or bearings.

When ordered with the clean-room option the XE will come factory prepared for most clean-room applications along with the clean-room lubrication, the XE offers an optional Raydent surface coating which protects against rust on the steel components for more than 10 years.

The integrated bearing arrangement, the rigid steel body, its ability to be easily integrated into multi-axis designs and that it is virtually adjustment free, and is priced extremely competitively making the XE series of actuators a significant force per UK pound value.