The >> principle is relatively simple: the extension of the stack changes roughly proportional to the drive voltage, with typical strain on the order of 0.1% of the stack’s length available. Charging and discharging of a piezo actuator is related to charging and discharging an electric capacitor.

 

 

Quasi-Static Applications

When static applications are concerned, i.e. several parts are to be aligned and held in place, piezo actuators work well, and their atomic-level resolution is welcome in many optics, laser and semiconductor related applications. However, each actuator will require a driver to maintain the required position. When the voltage source is removed, the piezo stack will slowly discharge and whatever dimensional change was affected by charging it will disappear.

Programmable Shims

A new technology, also based on the piezo effect, can be utilized in situations where high resolution and stability are crucial, but a continuous drive voltage is unwanted and accessibility for manual adjustment is not possible.

Applications for programmable (semi-active) shims can be found where the alignment between two or more subassemblies is critical and realignment may be required at some point due to environmental changes, creep or settling processes, etc.

Examples

Precision mechanical engineering·
High-end optical assemblies for astronomy and semiconductor manufacturing
Material research test systems in synchrotrons

Specifications

A variety of standard programmable shims are available as listed in the table below. Custom versions are possible.
* TH: Tower height OD: Outer diameter ID: Inner diameter 

  Dimensions*
in mm
Displacement
in μm
Tolerance of total displacement
OD × ID × TH    
PIRest Multilayer Ring Piezo Shim
(with inner hole)
8 × 4.5 × 8.5
8 × 4.5 × 16
8 × 4.5 × 36
2.9
5.8
13.3
±20 %
±20 %
±20 %
  OD × TH    
PIRest Round Multilayer Piezo Shim
(without inner hole, high blocking Force)
16 × 16
16 × 36
16 × 17
7.4
17
37.1
–10 % / ±20 %
–10 % / ±20 %
–10 % / ±20 %
  A × B × TH    
PIRest Multilayer Piezo Shim
(ceramic-insulated high power)
3 × 2 × 9
up to
10 × 10 × 36
3.4
up to 17
±10 %
±10 %
  OD × TH    
PIRest Encapsulated Piezo Shim
(For harsh industrial environments)
11.2 × 22.5
11.2 × 40.5
18.6 × 22.5
7.4
15.9
7.4
±10 %
±10 %
±10 %
  OD × ID × TH    
PIRest Chip Shim
(miniature with and without inner hole)
5 × 2.5 × 2.5
up to 16 × 8 × 2.5
1.06
up to 1.2
±20 %
±20 %
  A × B × TH    
PIRest Chip Shim (miniature multilayer piezo actuators) 2 × 2 × 2
up to 10 × 10 × 2
1.2 ±20 %

Ask an engineer!

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Downloads

pdf

Brochure: PIRest Actuators

Document language English
pdf - 3 MB


About this Author

Steffen Arnold

Leiter Marketing & Kommunikation, Physik Instrumente (PI) GmbH & Co. KG

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About this Author

Stefan Vorndran

Vice President - Marketing, PI (Physik Instrumente) LP

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