Micromechatronics, Inc. (MMech)

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

SA Stack Actuators

150V Piezoelectric Stack Actuators

SA_Stacks_small

Specifications:

Prod. Model Range +/-10% Lgth Cross Sect Cap. +/-20% Mass Block Force Stiff. Res. Freq.

um mm mm uF g N N/um kHz
SA030305 5.6 5 3x3 0.140 0.53 330 80 300
SA030306 7.0 6 3x3 0.180 0.6 330 66 250
SA030310 14 10 3x3 0.300 1.1 330 33 150
SA030318 25 18 3x3 0.500 2.0 330 18 83
SA050510 14 10 5x5 0.630 2.0 900 108 150
SA050520 31 20 5x5 1.8 4.0 900 41 74
SA050536 56 36 5x5 4.3 7.1 900 28 42
SA070718 28 18 7x7 4.1 7.0 1800 120 83
SA070742 70 42 7x7 10 15 1800 51 36

Features

The PiezoDrive SA stack actuators are high performance multilayer stack actuators with a 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, high speed, and exceptional reliability. The SA actuators are perfectly matched to the PiezoDrive PDX150b, PDQ150b, PDL200, and PDm200 voltage and charge drivers. Applications include: Nanopositioning, Microscopy, Precision Machining, Vibration Control, Hydraulic Pumps, Valves, and Optics.

 

Mounting Considerations

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.

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.

 

SA-Mount_Contact_Force_med

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 -1BE, or -2BE to the order code. E.g. SA070718-2BE.

SA_Ball_End_90

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.

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 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:

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, 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 - 1BE or 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_Dimensions_lg

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
MMechLogosm