What Are Piezo Actuators?

The purpose of an actuator is to convert electrical energy into mechanical energy. Piezoelectric actuators utilize the inverse piezoelectric effect to generate physical displacement in response to an electrical input. Piezo actuators are used for their precise control and efficiency in a wide variety of applications, with precision down to the micrometer. There are multiple types of actuators that suit different needs based on their unique properties.

Piezoelectric actuators are very simple in design with little to no maintenance or lubrication required. There are virtually no moving parts and they are quite reliable. For these reasons, they are best suited for applications requiring precise movement, for example in motors and a growing variety of other practical uses. Piezo actuators are widely utilized across many industries, including medical, industrial, commercial, machinery, automotive, and aerospace.

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Detailed Mechanics
Advantages and Disadvantages
Applications
Shapes

Detailed Mechanics

Detailed Mechanics of Piezo Actuators

The inverse piezoelectric effect occurs when an electrical charge generates mechanical energy. When an electrical voltage is applied to a piezoelectric actuator, the piezo actuator will deform and generate some kind of precisely controlled physical displacement. The resulting displacement can be used to activate switches or alarms, create sound, release fluid, auto-break or auto-focus, and much more. Low stroke or high stroke can be achieved depending on the shape and construction of the piezo actuator. The higher the mechanical stress on the piezo actuator, the high voltage produced. If one end of the piezo actuator is fixed, the other end bends to cause deflection. If both ends of the piezo actuator are fixed, the center deforms the most to generate displacement.

Piezoelectric actuators can either be constructed as a stack, bimorph, or unimorph, depending on the application and desired results. Stack piezo actuators generate low stroke, high blocking force, and high load capabilities making them extremely suitable for high precision applications given their ability to produce linear movement in small and precise amounts. Stack piezoelectric actuators can be made as either discrete stacks, where the components are fired separately and connected later via adhesive, or monolithic stacks where they are co-fired and bound by subjecting them to intense heat and pressure, or sintering. Bimorph and unimorph piezo actuators are constructed with layers of active piezoelectric material that bend and contract when a voltage is applied. Bimorph piezo actuators have two active piezo layers and unimorph piezo actuators have one active piezo layer often attached to a passive substrate layer. The electrical current causes one layer to contract and the other to expand, creating a bending motion. The resulting deflection generates more stroke and less blocking force than stack piezo actuators.

Advantages and Disadvantages

Advantages and Disadvantages of Piezo Actuators

Piezo actuators are extremely reliable and versatile. They are small, flexible, can be manufactured into any shape, and have no moving parts that require lubrication. Piezo actuators have very low energy consumption, high force generation and load capabilities, and can operate in vacuum and cryogenic environments. They have very fast response times and can be made to operate at high voltages. Piezo actuators may need to be mechanically preloaded or amplified if used as a driver depending on the application.

Applications

Sound generation and amplification
Musical pickups
Household commercial items
Alarms (microwaves, clocks, etc.)
3D and inkjet printers
Fine machinery
Fuel injectors
Valve and pump control
Ultrasound equipment
Microdosing and nanodosing

Applications of Piezo Actuators

Piezo actuators are a valuable and versatile element with limitless capabilities across all industries, such as commercial, industrial, automotive, aviation, aerospace, and electronic. In common household items, piezo actuators are responsible for igniting lighters, sounding alarms, and amplifying sound in speakers and microphones. Coupling the displacement’s power with rapid vibration makes for a clear sound with potent sound pressure. Sound-generating buzzers, alarms, and buttons implement piezo actuators to bend or deform at a signal and create a sound. This can be seen in timers, clocks, microwaves, car keys, PIN pads, and alarms and buzzers. Larger machinery such as 3D printers, inkjet printers, Braille machines, and weaving machines all utilize piezo actuators for fine movement and precise adjustments. In printers, piezo actuators are used to control the dispensing nozzle, releasing the precise amount of ink needed to create the print received through an electrical signal.

In the automotive industry, piezo actuators are found in fuel injectors, valve and pump control, and other auto functions, such as automatic breaking. Piezo actuators respond to electrical signals in the car’s computer and make mechanical and physical adjustments within the vehicle instantly.

Piezoceramic actuators are also excellent for high precision nano movement and dosing. In medical applications, piezoelectric tube actuators are employed in microdosing machines and ultrasound equipment. In some minimally invasive procedures, piezo actuators are implemented into catheters generate ultrasound waves, which increase the permeability of the blood vessel walls and make it easier for medication to penetrate.

Piezo actuators are a valuable and versatile element with limitless capabilities across all industries, such as commercial, industrial, automotive, aviation, aerospace, and electronic.

Shapes

Multilayer Stack Piezo Actuators

Multilayer stack piezo actuators consist of stacks of piezo elements that expand when an electrical charge is applied. Longitudinal and shear displacement can be achieved with stack piezoelectric actuators. Multilayer stacks are commonly utilized for precision machinery and control in industrial, medical, aerospace, and automotive industries. Learn more about piezo multilayer actuators here.

Disc Piezo Actuators

Piezoelectric actuators in a disc shape are circular piezo elements often found in automotive functions, sound production and amplification, liquid and fluid level measurement, and ultrasonic applications. As piezo actuators, discs are utilized in the automotive, industrial, commercial, and ultrasonic applications to detect changes and perform adjustments. Learn more about piezo disc actuators here.

Strip Piezo Actuators

Piezoelectric actuators in a strip shape are thin pieces of active piezoelectric material connected to a passive layer. Piezo strip bending actuators have either one active piezoelectric layer or two active piezoelectric layers that bend to create deflection. Strip piezo actuators are commonly utilized in valve and pump controls, accelerometers, sound production, touch switches/controls, and fine machinery. Learn more about strip piezo actuators here.

Ring Piezo Actuators

Piezoelectric actuators in a ring shape are often used in multilayer stack piezo actuators to produce linear movement. Ring piezo actuators are often found in ultrasonic applications, nanopositioning, microscopy, and precision machining. Learn more about piezo ring actuators here.

Tube Piezo Actuators

Piezoelectric actuators in a tube shape are also known as piezoelectric cylinders. Tube piezo actuators can generate axial displacement (changes in length) or radial displacement (changes in diameters). Tube piezoelectric actuators are often utilized for flow and level measurements and adjustments, scanning microscopy, and microdosing, commonly found in the industrial and commercial industries. Learn more about piezo tube transducers here.

Bimorph Piezo Actuators

Bimorph piezoelectric actuators consist of two active piezoelectric layers bonded to a passive metal substrate or bonded directly together. One piezoelectric layer contracts while the other piezoelectric layer expands when a mechanical or electrical input is received. This causes a bending motion that can either perform a desired task or generate a readable electrical output. Learn more about piezo bimorph transducers here.

Unimorph Piezo Actuators

Unimorph piezoelectric actuators consist of one active piezoelectric layer often bonded to a passive metal substrate. Unimorph actuators deform in a single direction when activated by an electrical input and translate it into a mechanical output.

Plate and Block Piezo Actuators

Piezoelectric actuators shaped as plates and blocks can be engineered into any shape. Plate piezo actuators are commonly used in multilayer stack actuators and block piezo actuators are often used in ultrasonic applications. A DC voltage will cause piezo plate actuators to deform while an AC voltage will cause it to vibrate. Piezo block actuators are used for high power generation and applications. Learn more about plate and block piezo actuators here.

Piezo Actuators