Posted by Mike Greig on 8/10/2021
Let’s face it, trying to spec out components for a product can be a challenge, and actuators are no exception. Trying to choose the correct actuator for a specific application can be overwhelming. From different motor types and inputs/control modes, to gear ratios, stroke, mounts and lead screw type, it can be a little much to take in if you’re new to actuators.
Today we are going to take a look at part of that process. Specifically, the differences between ball screw and lead screw actuators, and why you might choose one over the other. Let’s dive in.
What are Lead Screws?
Most linear actuators work more or less the same. A rotary motor turns a screw, which in turn drives a shaft in and out. This is how rotary motion is converted to linear motion. With a basic lead screw, the screw drives through a nut made of delrin or another material that is mounted to the shaft. As it turns, it drives the shaft in and out.
This type of screw creates friction between the screw and the nut. Because of this, actuators that use lead screws typically have a higher back drive force and a braking effect when power to the drive motor is shut off. Lead screws are a great choice for applications where you want the actuator to hold its position even under some load, and product cost is a consideration.
What are Ball Screws?
A ball screw actuator is functionally similar to a lead screw actuator. The difference is that with a ball screw actuators, rather than the screw threading through a matching nut, there are ball bearings between the screw and the nut. There are several advantages to using a ball screw actuator. First, the use of ball bearings to drive the screw creates less friction than a standard lead screw. This means that the actuator can be driven faster, while creating less heat. This can extend the life of the actuator in the long-term.
Generally, ball screw actuators are capable of handling heavier loads and more side load than lead screws. It is also possible to make ball screws much more accurate, as the clearances are incredibly tight. The downside is that they provide little or no back drive force and are typically more expensive than lead screw actuators.
All Actuonix actuators are lead screw-type actuators. As mentioned above, a lead screw system works very well for many applications and helps reduce the cost of our customers projects.
This article was intended to give you a general overview of lead screw actuators and ball screw actuators. Neither one is better than the other, there are strong positives and a couple of negatives to either choice. At Actuonix, we offer a wide range of lead screw rod, track and stepper actuators to suit the needs of design engineers. You can find our full range of products in our online store or contact our sales department today if you would like help choosing the best actuator for your application.