3D Print Your Own Linear Actuators

If you need to move something using electricity, you look to electric motors. There are other alternatives, such as electromagnetic solenoids, but they have serious disadvantages. In most cases, an electric motor is the best choice. But those produce rotary motion, so what do you do if you need to move something in a linear fashion? The solution is a linear actuator and this handy guide by PHYTION will walk you through how to build your own using affordable components and 3D-printed parts.

Linear actuators come in a few different varieties. Hydraulic and pneumatic versions simply push a piston by pumping in fluid — air or hydraulic oil. Electric types convert the rotary motion from a spinning electric motor into linear motion and they can do that in a couple of different ways. They can, for example, work like a rack-and-pinion. But the type in this tutorial uses a lead screw mechanism. It is similar to the Z axis on your 3D printer, with the lead screw spinning to push a nut on the piston in or out.

The advantage of this design is that it can produce quite a lot of torque, even from a low-power electric motor. The ratio will depend on the thread pitch, but it is gearing down the motor output quite a lot, sacrificing speed for torque.

To keep the cost down, PHYTION’s design uses a standard nut and basic threaded rod from a hardware store. The piston is aluminum tube and PVC pipe. The rotary input comes from an inexpensive electric gear motor. A few 3D-printed parts help hold everything together and provide mounts at both ends.

Fabricating this linear actuator is mostly a matter of printing the parts, cutting the tubes to length, and gluing everything together.

This isn’t, of course, a heavy-duty linear actuator for moving serious loads. But it should work well for DIY robotics and will provide a decent amount of torque with good precision — though you’ll need additional hardware to determine the position of the piston.