Micromechatronics, Inc. (MMech)

www.mmech.com - Ph: 814-861-5688

SR Ring Stack Actuators

150V Piezoelectric Ring Stack Actuators

Ring_Stack_med

Specifications:

Prod. Model Range +/-10% Length OD ID Cap. +/-20% Block Force Stiffness
SR080410 14 um 10 mm 8 mm 4.5 mm 0.8 uF 1300 N 130 N/um
SR080418 28 um 18 mm 8 mm 4.5 mm 1.6 uF 1300 N 6.5 N/um
SR120610 14 um 10 mm 12 mm 6 mm 2.4 uF 3000 N 220 N/um
SR120620 30 um 20 mm 12 mm 6 mm 5.0 uF 3000 N 100 N/um

Features

The PiezoDrive SR ring stacks are high performance multilayer actuators with a vacuum compatible polymer coating and a large central aperture. The SR rings stacks are perfectly matched to the range of PiezoDrive amplifiers and driver modules. Applications include: Optics, Microscopy, Nanopositioning, and Precision machining.

 

Mounting Considerations

Stack actuators should not be exposed to significant tensile loads, unequally distributed loads, off-axis loads, bending moments, or torque.

SA-Mount_Contact_Force_med

The maximum recommended tensile load is 10% of the blocking force. In applications that require bi-directional forces or high speed motion, a preload force is recommended with a magnitude greater than the maximum tensile load. This gaurantees that the actuator is always in compression.

Range

The range is specified for an applied voltage of -30V to +150V. If the input voltage is unipolar (0V to +150V) the specified range is reduced by a factor of 0.75. When a stack actuator is driving a stiff spring, the range is reduced by the factor

SA_eq1

where kp is the actuator stiffness and kL is the load stiffness.

The travel range can also be reduced by restraining the end plates, e.g. by bonding the actuator to a stiff base. This effect is most significant in actuators with a length less than twice the outside diameter.

Capacitance

The actuator capacitance is the small-signal capacitance measured at room temperature. Due to hysteresis, the effective capacitance increases with applied voltage. When operating at full range, the effective capacitance is approximately twice the small-signal capacitance. The capacitance also increases with temperature. A temperature increase of approximately 50 degrees C will double the effective capacitance.

Thermal

Piezoelectric actuators dissipate heat when driven at full range with a high frequency. PiezoDrive actuators can be operated continuously at temperatures up to 85 degrees C. Continuous operation beyond this temperature may damage the actuator.

The dissipated heat is approximately 10% of the applied electrical power. For a sine-wave, the applied electrical power is:

SA_eq2

Electrical Current Requirements

The required current is I=C dV/dt where I is the current, C is the effective capacitance, and dV/dt is the voltage rate of change. For a sine-wave, the required peak current is equal to:

SA_eq3

where Vp-p is the peak-to-peak voltage. For a triangle wave, the required peak current is equal to:

SA_eq4

Recommended Drivers

Amplifier Application
PDm200B General purpose, low cost
MX200 High Current, Low noise, low cost
PDu150 Ultra-low noise
PD200 High speed, low noise
PX200 High current, low noise

 

Connecting Wires

All of the connecting wires are 100mm AWG26 PTFE insulated wires. Other lengths are available on request. Red identifies the positive terminal.

Vacuum Compatibility

The SR Actuators are supplied with either vacuum compatible polymer encapsulation or a UV cured lacquer coating. Both coatings and the wiring insulation meet the outgassing requirements for NASA SP-R-0022A.

Options / OEM Customization

  • Custom range and dimensions
  • Custom wiring arrangement/connectors
  • Preload or mechanical amplifier mechanisms

Piezoelectric Properties

The piezoelectric material is similar to PZT-5H and Navy Type VI.

SA_piezoprops_med

More Information

200 Innovation Blvd. Suite 155
State College, PA 16803, USA
Ph: (814)-861-5688
Fax: (814)-861-1418
contact@mmech.com
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