Linear Motor Stage and Direct Drives
Direct Drive and Linear Motor Stages
Below is a selection of direct drive and linear motor products from our portfolio, and each can be modified and configured to meet your specific needs. Contact us if you don’t see exactly what you are looking for. We can help you identify the right motion solution for your application.
The Benefits of Using Direct Drive Linear Motor Stages
Direct drive systems using linear servo motors have a number of advantages over more traditional belt-drive, lead screw, or rack and pinion actuators. These include:
- Fewer parts
- No wear
- No particulation
- Consistent servo tuning from unit to unit and over time
- Lower audible noise
- Higher speed
- Higher acceleration
- Greater accuracy
- Greater repeatability
How Direct Drive Linear Servo Stages Work
In a direct drive linear servo motor stage, a linear encoder is used to close the position feedback loop. Meaningful resolutions and position stability of less than one nanometer can be achieved with the use of modern fine pitch optical linear encoders and deep arc-tan encoder interpolation. The non-contact nature of linear motors that drive linear motor stages is especially valuable when teamed with equally non-contact linear encoders and air bearing guideways. For short strokes, single phase linear motors simplify the electronic drive and control. Linear servo motors typically employ 3 phases and the motion controller drives sinusoidal currents into the 3 phases to provide constant force for extended travel. Linear servo motors can be flexibly scaled to fit into very constrained spaces, and can also scale up for linear motors that handle very large payloads.
The key quality factor to maximize is called Km, the unit of Newtons per root watt. The force capability of the motor is limited by its thermal power dissipation, which scales as (Force/Km). To achieve higher force capability, one wants to increase Km. This can be achieved by increasing the magnetic flux density and/or the active copper volume. Winding the motor coils with flat wire increases their copper packing fraction, which allows the active copper volume to be increased without changing the overall motor coil dimensions.
Please contact us if you’d like additional information about direct drive linear motor stages. We’re happy to answer any questions and help you find the right solution for your precision motion needs.