Linear Actuators – High Precision Motorized Actuators

There are many different types of linear actuators, consider the following factors when buying a motorized precision linear actuator:

1. Drive Type: Motorized linear actuators are available with stepper motors, voice-coil motors, piezo motors, with closed-loop position feedback for highly precise and repeatable motion, with direct-drive motors for higher speed, and screw drives for higher force. See examples and specifications of representative models on this overview page above to give you a basic understanding of capabilities and limitations.
2. Push/Pull Force, Stiffness, and Size: Consider the mass, size, and inertia of the object that the linear actuator will need to move. Do you have an external guiding system or will the actuator have to provide precision guidance, too? An actuator with a higher load capacity will provide a longer lifetime, especially in high duty cycle applications.
3. Drive Mechanism / Bearing Type: In general, ballscrews provide higher velocity and lower friction, but unlike leadscrews lack self-braking capability, which might be important in vertical applications. Piezo-motor actuators are compact, provide self-locking capabilities, and extremely high resolution but require different drivers than simple stepper-motor-driven actuators. Air bearing actuators provide the highest accuracy and lifetime, as well has the best controllability for extremely small forces since they are friction-free and maintenance-free.
4. Travel Range: This refers to the total displacement the actuator can provide. Here, screw type actuators provide the longest travel ranges, while piezo stack actuators or flexure actuators are friction free and provide very fast response times to the sub- millisecond range, but travel ranges are limited to the low millimeter range. Piezo-motor actuators, such as the Piezowalk actuators, can provide 100mm or more and forces to 800N. Voice coil actuators are used for highly dynamic scanning or step-and settle applications with typical travel ranges of 25mm or less. They also need weight force compensation in vertical applications such as the V-308 fast focus actuator.
5. Acceleration and Speed: Higher velocity and acceleration can be achieved with direct-drive motors (voice-coil, three-phase linear motors, ultrasonic piezo motors). Lead-screw or ballscrew actuators can provide higher force. The motor size and motion controller will have a big influence on step-and-settle performance.
6. Accuracy, Repeatability, and Resolution: Actuators with integrated linear encoders provide the highest repeatability and accuracy compared to open loop stepper motor actuators or motor mounted rotary encoders. Piezo stack actuators and amplified actuators provide the best dynamics and precision, however with limited travel ranges.
7. Environmental Compatibility: Vacuum compatible actuators require careful designs with reduced outgassing. Air bearing actuators are ideal for clean rooms, and since frictionless, can virtually run forever without maintenance.
8. Support and Warranty: Check the level of technical support provided by the manufacturer, as well as the warranty terms. Always discuss your actuator requirements with a knowledgeable engineer at the manufacturer or supplier to ensure you choose the most suitable linear actuator for your application.