Piezo stages are part of the direct drive family of linear motion stages. This includes linear motors, shaft motor and stages with voice coil motors. The drive mechanism in each of these motors is free of mechanical rolling or sliding elements, offering long life and minimum wear. PM designs customised positioning stages with different drive mechanisms for various applications and markets. On this page, you will find general information and examples of piezo stages.
In the world of precision stage design for linear motion, many options for the drive are available. Just to name a few, ball screw, linear motor, or rack and pinion. They all have their characteristics in velocity, acceleration, positioning accuracy, positioning stability, and size. There is no single drive that works for every application and it is often not so easy to decide which motor or actuator is the best for a specific application. Some of the general selection criteria are:
When it comes to piezo motors, the main technical features to use them are:
Minimum space requirements
Rapid response time
Ultra-high positioning accuracy
High positioning stability
Able to move low-medium loads
Maintenance and lubrication free
UHV compatible and non-magnetic available
Offering sub-micron resolution
PM has designed numerous customised stages, in particular, piezo stages in many different configurations. On this page, you will find a small selection of the different precision stages with a piezo drive that we have developed over the years.
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Unlike ball screw stages, it is for piezo-driven stages easier to be designed for longer travel lengths. They don’t have any transmission, such as a gearbox or coupling. This keeps the overall length short and fewer components are used. Piezo stages are popular in combination with linear crossed roller bearings. This type of bearing offers the best precision in motion of any mechanical bearing. The travel of crossed roller bearing stages is limited by the length of the rails in combination with the cages. The typical travel range of piezo motor stages is between 5 and 500 mm.
Piezo stages can be used in every orientation. For Z-direction there is no need for gravity compensation as they are self-locking. Even when the motor is switched off, piezo stages will keep their position which is limited by a maximum holding force.
PM has many years of experience in designing and manufacturing ultra-high positioning stages for use in (ultra-high) vacuum environments. Examples are x-ray, e-beam, electron microscopes, beamline instrumentation, or EUV lithography. Selection of suitable materials (like aluminum, stainless steel, and ceramics) and components, ceramic linear guides, sensors, cables & connectors, lubricant, vented screws, but also arrangements done on the manufacturing of the stage parts itself on outgassing to avoid air inclusions to reduce pumping time. Piezo-driven positioning stages are supplied according to the cleaning standards provided by the customer.
This stage was designed by PM for use in an ultra-high vacuum environment. All axes include compact piezo stepper motors. The motors are positioned between the linear bearings. The linear bearings are crossed roller linear guides, offering smooth and accurate motion. The bottom axis is a Z-axis to lift the XY stage to bring the sample into focus. The strokes of this stage are 15 x 15 x 10 mm.
Qualification can be done on cleanliness/particles, leak tests, and testing of small stages in vacuum chambers.
This stage is an engineered solution for a customer asking for nanometer requirements in 3 motion directions. The XY has a compact design and consists of 3 main parts. The intermediate part combines the top plate of the X-stage and the bottom plate of the X-stage resulting in higher accuracies compared to stacked designs. The piezo motors are positioned in the center of the axes to eliminate any driving moments. Stroke lengths are 20 x 20 x 20 mm.
Long travel stages for sub-micron positioning accuracy can also use piezo motor technology. The motor stays stationary and is pushing against a ceramic strip that is mounted to the lateral stage surface. In this case, the travel is limited by the travel length of the linear guides in combination with the roller cages. These types of stages can be supplied with long travels. The below image shows a piezo-driven XY-positioning stage with stroke lengths of approx. 500 x 500 mm.
PM manufacture gonio bearings for a curved motion. These bearings are also used in gonio stages where we designed single-axis and multi-axis stages like an XY-Gonio stage. A small piezo motor with a linear encoder is mounted in the center line of the table enabling a stroke of ± 5 degrees.
Applications that require vertical motion with high rigidity, high-accurate travel, and positioning accuracy, use wedge-style arranged crossed roller linear bearings. By moving the table in a horizontal plane, the wedge arrangement of the linear bearings transforms this motion from the drive motor into a vertical motion. Here you can see two examples of driving mechanisms used by vertical lift stages, one with piezo motor drive and one with ball screw drive. We have designed Z-stages with strokes starting from 2 mm up to 25 mm.
PM is a developer and supplier of (ultra-high) precision stages with in-house engineering and manufacturing capabilities, located in the Netherlands. With over 50 years of experience, PM provides systems worldwide to customers active in fields like the semiconductor, medical and analytical industries. PM has a strong focus on ultra-high precision and is the leading company in this area. They do not supply stages from a catalog, but all stages are custom designed to fit perfectly your application. Contact us today to discuss your motion design needs.