Linear actuators are designed to generate mechanical linear motion by converting other forms of energy into mechanical energy. An actuator is usually an integral part of a motion control system in an automated assembly process. Linear actuators are almost always computer-controlled, although some can be guided by hand. A linear actuator can be powered by either hydraulic, pneumatic, mechanical, electromechanical and piezoelectric force.
One purpose and application of linear actuators is to act as a mechanism that can transmit a very precise amount of energy to another mechanism or piece of equipment in a system. Linear actuator manufacturers contribute to the function of robotic processes in many different industries, including automotive, biotechnology, pharmaceuticals, food, packaging and electronics.
For specialized applications, it is typical to use piezoelectric and telescopic actuators. Piezoelectric actuators are very small and precise. In a piezoelectric setup, spindle actuators provide vertical motion. Almost all automation processes in factories or other industrial settings use linear actuators so that they can push, rotate, transport or life parts and equipment during manufacturing. Linear actuators can even be made to operate in unusual conditions like underwater environments or in the presence of a vacuum. Read More…
Linear motion is achieved in most actuators through a ball screw design. A screw rod rotates in and out of a housing, causing linear motion. A timing belt drive, worm gear or direct drive is used to rotate a ball screw actuator. As the screw turns, it pushes a drive nut along the length of the screw, and this causes the rod to be pushed out. When this motion is reversed, the rod retracts. A cover over the screw keeps out dirt and other contaminants that could hinder movement. Even when it is loaded, special radial thrust bearings allow the screw to move freely. Although rotary actuators are not linear, they can be used for very similar purposes in automated assembly applications. Mini linear actuators for small applications tend to be electric. However, some use piezoelectric power for precise and short movement.
Factors that should be considered when choosing a linear actuator include:
Speed: The linear actuators speed is a measure of how quickly the actuator can extend and retract. Some applications may require that the actuator move quickly, while others may require slower, more precise motion.
Stroke length: The stroke length of the actuator determines how far it can extend from its starting position. For small-scale tasks, a shorter stroke length is typically required, but for actuators used in machining equipment and larger machinery, a longer stroke length may be required.
Load rating: When used to push or pull an object, the linear actuator will have to be able to handle the weight of that object in order to actually move it. The load rating indicates the weight limit, or load limit, of the actuator.
Programmability requirements: Most linear actuators are used to perform automated tasks and, therefore, require at least some level of programming to interact with the system in which they are being used. Some actuators can only be programmed for simple inputs while others have much more complex programming capabilities.
Desired lifetime: Depending on the materials used, the environment to which the actuator is exposed, and the manufacturing quality, a linear actuator will have varying longevity. Obviously, the more durable and the higher the quality of the actuator, the longer it will most likely last.
Type of motor and power: Linear actuators can be powered in many different ways, including electrically, hydraulically, and pneumatically, and there are many different types of motors used to generate that power. Some actuators can run on batteries, while others will use AC, DC, or other specialized motors.
Power-to-weight ratio: While not always the case, larger actuators are typically capable of providing more power while smaller actuators provide less. Larger actuators will take up more room and generally way more as well. For weight-sensitive applications, finding the right balance of size, weight, and power is an important task.