The tensile strength of a stacked actuator is largely determined by the method used to laminate the individual elements together, and is generally an order of magnitude lower than the compressive strength. Stacked piezo actuators often see both compressive and tensile forces, especially during highly dynamic movements. Stacked actuators are also able to hold their position when power is off, and can do so without generating heat. It’s important to note that in steady state operation (no movement, constant force), no current is flowing and no power is required. Force and StiffnessĪctuator stiffness has a significant influence on force generation, and is determined by the modulus of elasticity of the piezo ceramic material, the actuator’s cross-sectional area, and its length.ĭespite their small size, stacked piezo actuators have a force density in the range of 30 N/mm 2, which allows them to produce useful forces in the tens of thousands of Newtons. Similarly, for a given electrical field, the driving voltage must decrease as the layer thickness decreases. Thus, the electric field increases as the layer thickness decreases.

The relationship between the electrical field and the driving voltage is given by the equation: The amount of voltage that can be applied is determined by the material and the thickness of each element. Stacked piezo actuators are generally classified as either low voltage (below 200 V) or high voltage (up to 1000 V), referring to the maximum input voltage for maximum stroke. Image credit: PI Ceramic GmbH Voltage and Electric Field In a stacked piezo actuator, the total displacement is the sum of each layer’s individual displacement. When a voltage is applied in the direction of polarization, displacement is produced. The total displacement of a stacked actuator is generally between 0.1 and 0.15 percent of the actuator length. (The piezo electric coefficient, d 33, relates to the material’s efficiency in transferring electrical energy to mechanical energy.) Because they are connected mechanically in series, the total movement of a stacked piezo actuator is the product of a single element’s movement, times the number of elements in the stack.ĭ33 = longitudinal piezo electric coefficient (m/V) The movement of a piezo element equals the amount of voltage applied multiplied by the piezo electric coefficient.

When a voltage is applied, a strain, or displacement, is induced in the direction of polarization. Individual piezo elements in a stacked actuator have alternating polarity, and the electrical field is applied parallel to the direction of polarization. These devices take advantage of the combined effect of each element’s expansion to produce a useful movement and force. Multiple piezo elements can be layered on top of each other, creating what is known as a stacked piezo actuator. We can provide a variety of customized products such as single layer design and also multilayer design.A piezo element is a ceramic that expands or contracts when an electrical charge is applied, generating linear movement and force.Our unique HIP technologies can offer piezoelectric materials for single layer type product with less voids which are suitable for micromachining.We offer various kind of materials suitable for our customer's needs and usages.Our unique HIP * processing can contribute to high-density piezoelectric materials which enables micromachining on single layer type.

We can offer piezoelectric materials with single layer type and multilayer type according to customer requests for the development of piezoelectric ceramic devices. Suitable piezoelectric materials for various usages can be selected from our wide varieties of product lineup.

Multilayer piezo actuator