Piezoelectric stack (piezo stack actuator)

01

Pick the drive voltage and stack construction

PI describes piezoelectric actuators as ceramic actuators that convert electrical energy directly into linear motion with high speed and force, and lists stack types from bare multilayer stacks of 2 × 2 to 10 × 10 mm cross-section with 5–70 µm travel and discrete stacks of 5–56 mm diameter with 5–180 µm travel, to encased, preloaded stacks with travel to 180 µm and force to 30 kN. [1]

Its PICMA Stack multilayer actuators run at −20 to 120 V, with ceramic, polymer-free insulation, humidity resistance and UHV compatibility to 10⁻⁹ hPa; encapsulated versions are offered for splash water or oil, and custom designs for up to 200 °C. [2] Its PICA Power discrete stacks run at 0 to 1000 V, with an integrated PT1000 temperature sensor against overheating, a lifetime stated as more than 10⁹ cycles, sub-nanometre resolution and microsecond response, for active vibration damping, precision machining and adaptive structures. [3]

Editorial note: the drive voltage sets the amplifier you need — a 120 V multilayer stack and a 1000 V discrete stack are not interchangeable on the same driver — and the capacitance sets the current the amplifier must supply for dynamic motion. [2] [3]

Give the supplier the stroke needed under load, the load mass and external stiffness, required force, drive voltage available, bandwidth or frequency and duty, position sensing needs, operating temperature, humidity or vacuum, mounting and end pieces, size limits, lifetime in cycles and quantity.

02

Size travel, blocking force, stiffness and dynamics

PI's PICMA table runs from the P-882.11 (3 × 2 × 9 mm: 6.5 µm nominal, 8 µm maximum travel, 190 N blocking force, 24 N/µm, 0.15 µF, 135 kHz) to the P-888.91 (10 × 10 × 36 mm: 32 µm nominal, 38 µm maximum, 3,800 N, 100 N/µm, 13.0 µF, 40 kHz). Nominal travel is at 0–100 V and maximum at 0–120 V; resonant frequency is measured unloaded and unclamped and is halved for unilateral clamping. Operating temperature is −40 to 150 °C. [2]

The PICA Power table runs from 10 mm diameter, 5 µm travel, 1,200 N blocking force and 240 N/µm to 56 mm diameter, 180 µm travel, 70,000 N and 390 N/µm, with capacitance in nanofarads (17–21,000 nF) and resonance from 129 kHz down to 7 kHz as length grows; it operates at −20 to 150 °C. Both product lines recommend 15 MPa preload for dynamic operation and a maximum 30 MPa preload for constant force. [3] [2]

Editorial calculation: blocking force is close to stiffness times maximum free travel — for the P-888.51, 200 N/µm × 18 µm = 3,600 N, matching the listed value. Treating the stack as a linear spring, the force available falls from the blocking force at zero travel to zero at full travel, so a load needing half the blocking force leaves about half the free travel. [2]

03

Multilayer piezo ceramics and stack actuators listed by Nanjing Hanzhou

Ask each supplier for the data table with test conditions for travel, blocking force, capacitance and resonance, the ceramic material, insulation and encapsulation, preload recommendations and lifetime data. [2] [3]

04

Set load limits, drive current and humidity before ordering

PiezoDrive's SA series of 150 V stacks, with blocking forces of 330 N, 900 N and 1,800 N, states mounting limits: no significant tensile, off-axis or unequal loads, bending or torque; maximum tensile load 10% of the blocking force; for bi-directional or high-speed motion a preload greater than the maximum tensile load; and maximum preload 50% of the blocking force. Driving a stiff spring cuts range by kp/(kp + kL). [4]

Effective capacitance at full range is about twice the small-signal value, and a temperature rise of about 50 °C doubles it; peak current for a sine wave is π·C·f·Vp-p, and about 10% of the electrical power becomes heat. The stacks run continuously up to 85 °C at up to 75% RH, non-condensing. At 75% RH and +150 V DC, leakage rises by about 1 µA/µF every 100 hours, halving for every 20 V or 10% RH reduction. [4]

Editorial calculation: the SA050510 (630 nF, 900 N) allows up to 90 N tension and 450 N preload; at full range its effective capacitance is about 1.26 µF, so a 150 V, 1 kHz sine needs a peak current of π × 1.26 µF × 1,000 Hz × 150 V ≈ 0.59 A. [4]

05

Ceramic layers, electrodes, insulation, end pieces, leads and temperature sensor

PI's two lines differ row by row: PICMA uses PIC252 ceramic with polymer-free ceramic insulation, while PICA Power uses PIC255 with a FEP shrink tube, steel end plates and a PT1000 sensor. [2] [3]

06

Voltage, travel, blocking force, stiffness, capacitance and resonance for a piezo stack order

Each row gives the PICMA range first and the PICA Power range second; PI measures capacitance at 1 V and 1 kHz and resonance unloaded and unclamped, so ask for both under your own clamping. [2] [3]

07

Send the stroke, load and drive data together

Paste it into your enquiry below or into an email to a maker, then replace every bracket.

Stroke: [µm under load]
Load: [N; external stiffness; mass]
Drive: [V range; amplifier]
Dynamics: [Hz; duty; cycles]
Preload/mounting: [MPa; end pieces]
Environment: [°C; RH; vacuum; oil]
Size: [section; length]
Quantity: [units]

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