PiezoWalk® Piezo Motors

Nanometer Precision with a High Feed Force

  • Integration levels from an OEM motor to a multi-axis positioning system
  • Scalable travel range due to scalable runner length
  • Resolution to 0.03 nm
  • Self-locking when at rest, no heat generation
  • Nonmagnetic and vacuum-compatible operating principle

PiezoWalk® drives were developed more than 10 years ago for the semiconductor industry, which is a very demanding industry when it comes to reliability, position resolution and long-term stability. PI received the SEMI Technology Innovation Showcase Award for the PiezoWalk® technology in 2005. The drives are continuously developed further, and a large number of variants are now available for different areas of application.


Operating Principle of PiezoWalk® Linear Motors

As essential components, these piezo stepping drives have several piezo actuators that are preloaded against a guided runner.

These piezo actuators perform a stepping motion during operation that causes a forward feed of the runner. The piezo actuators can be operated to perform very small stepping and feed motions so that a high motion resolution of far below one nanometer is achieved.


Characteristics of Stepping Drives

Piezo stepping drives do not require any mechanical components such as coupling or gearhead, which cause friction and backlash and would considerably limit the precision and reliability of high-resolution spindle-based motor drives.

 

Piezomotors are Self-Locking

Preloading the piezoceramic actuators against the runner ensures self-locking of the drive when at rest and powered down. As a result, it does not consume any power, does not heat up, and keeps the position mechanically stable. Applications with a low duty cycle that require a high time and temperature stability profit from these characteristics.

 

 

Lifetime and Reliability

The motion of the piezoceramic actuator is based on crystalline effects and is not subject to any wear. Unlike other piezomotor principles, the coupling of the piezo actuators to the runner is not subject to sliding friction effects; the feed is achieved by the physical clamping and lifting of the actuators.

 

 

Piezo Motors for All Applications

Piezomotors from PI are vacuum-compatible in principle and suitable for operation under strong magnetic fields. For these purposes, special versions of the drives are offered. Piezo stepping drives can also be used in clean rooms or in environments with a hard ultraviolet radiation.


Products: Two Technologies for More Flexibility

For the piezo stepping drives, PI uses two different technologies that can be adapted to the respective requirements:

  • NEXLINE®

High-load stepping drives combine piezo clamping and shear actuators, in order to move a rod. The drives feature particularly high forces and stiffnesses at feed forces of several 100 N.

They are capable of dynamically compensating oscillations in the range of a few micrometers with nanometer resolution, are designed for higher positioning and holding forces of up to 800 N, and work at lower velocities.

  • NEXACT®

Precision stepping drives convert the stepping motion by means of piezo bending elements. These drives are more compact and achieve higher velocities, developing forces in the range from 10 to 20 N.

A suitable selection of the piezo elements optimizes step size, clamping force, velocity, and stiffness for the respective applications.

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Patents

PI owns the following patents or patent applications for the technology field Piezo Stepping Drive (PiezoWalk®, NEXACT®, NEXLINE®):

DE10148267B4
EP1267478B1
EP2209202B1
EP2209203B1
US6800984B2
DE4408618B4