150V Piezo Stack Actuators

SA Piezoelectric Stack Actuator

The PiezoDrive SA stack actuators are high performance multilayer stack actuators with a vacuum compatible polymer coating for improved reliability and protection against dust and humidity. PiezoDrive actuators are designed for applications that require long range, high force, nanometre resolution, and high speed. The SA actuators are perfectly matched to the range of PiezoDrive amplifiers and driver modules. Applications include: Nanopositioning, Microscopy, Precision Machining, Vibration Control, Hydraulic Pumps, Valves, and Optics.

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Specifications

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Order
Code
Range
+/-10%
Length Cross Section Cap.
+/-20%
Mass Blocking Force Stiffness Resonance
Freq.
SA030305 5.6 um 5 mm 3 x 3 mm 140 nF 0.53 g 330 N 80 N/um 300 kHz
SA030306 7.0 um 6 mm 3 x 3 mm 180 nF 0.6 g 330 N 66 N/um 250 kHz
SA030310 14 um 10 mm 3 x 3 mm 300 nF 1.1 g 330 N 33 N/um 150 kHz
SA030318 25 um 18 mm 3 x 3 mm 500 nF 2.0 g 330 N 18 N/um 83 kHz
SA050510 14 um 10 mm 5 x 5 mm 630 nF 2.0 g 900 N 108 N/um150 kHz
SA050520 31 um 20 mm 5 x 5 mm 1.8 uF 4.0 g 900 N 41 N/m 74 kHz
SA050536 56 um 36 mm 5 x 5 mm 4.3 uF 7.1 g 900 N 28 N/um 42 kHz
SA070718 28 um 18 mm 7 x 7 mm 4.1 uF 7.0 g 1800 N 120 N/um83 kHz
SA070742 70 um 42 mm 7 x 7 mm 10 uF 15 g 1800 N 51 N/um 36 kHz

Mounting

Stack actuators should not be exposed to significant tensile loads, unequally distributed loads, off-axis loads, bending moments, or torque. To reduce mounting errors, a ceramic or stainless steel ball end can be used to interface the stack actuator to the load. Flexural mechanisms are also recommended.

Stack Actuator Mounting Considerations Stack Actuator Mounting Considerations

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. The maximum recommended preload is 50% of the blocking force.

Ball Ends

Piezoelectric Stack Actuator with Ball Ends

PiezoDrive stack actuators can be supplied with Saphire ball ends to improve the load distribution, simplify the mounting, and reduce bending moments during service. One or two ball ends can be specified by adding one of the following suffixes to the order code: -TBE (Top Ball End), -BBE (Bottom Ball End), or -2BE (Both Ball Ends). E.g. SA070718-2BE.

Actuator Width Ball End Diameter Additional Length
3 mm 3 mm 3 mm
5 mm 5 mm 5 mm
7 mm 6.5 mm 6.5 mm

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 $$\frac{k_p}{k_p+k_L}$$ where \(k_p\) is the actuator stiffness and \(k_L\) 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 that have a length less than twice the width.

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: $$P = \frac{V_{p-p}^2 \pi C f}{4}.$$

Electrical Current Requirements

Calculate Power Bandwidth

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: $$ I_p = 2 \pi f V_{p-p} $$ where \( V_{p-p} \) is the peak-to-peak voltage. For a triangle wave, the required peak current is equal to: $$ I_p = 2 C f V_{p-p} .$$

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, except for the SA030306 actuator which has 15mm leads. Other lengths are available on request. Red identifies the positive terminal.

Vacuum Compatibility

The SA 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

  • Ceramic ball ends (Order suffix - 2BE)
  • Custom range and dimensions
  • Custom wiring arrangement / connectors
  • Preload or mechanical amplifier mechanisms

Dimensions

The total stack dimensions are based on the width and length of the ceramic listed in the specifications. The length specification includes the piezoelectric stack and two 1-mm thick ceramic end plates.

SA Stack Actuator Dimensions

Piezoelectric Properties

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

Piezoelectric Properties