Linear Motion Compliant Mechanism

This project shows how 3D printing can make motion systems that move really, really small distances. Flexures use the flexibility of a material instead of hinges or gears to create mechanical assemblies. This kind of thing is typically used for aligning optical components or sensors in precision assemblies. This is a good teaching prop on what is possible with flexures, where two mechanical step-downs and one linear motion stage are combined into a single part.

In practice, this is a fun way to show that a low-precision 3D printer can make a device that has extremely high precision, showing one way machines can bootstrap up the precision chain. Flexures are interesting because they dramatically reduce part-count, need no lubrication, have no lash, and with the right design/material they can have absolutely no wear. This is why flexures are often used for critical applications like the arming & disarming of nuclear systems and satellite components!

This uses an m3 screw (tapped into the center hole) as a source of linear motion. The rest of this design is planar, meaning it could be cut using a laser or waterjet from other materials (like Polypropylene or Aluminum.)

Here’s a video of this piece translating linearly below what my dial indicator can measure (sub-micron) https://youtu.be/QIBc27owVFo?si=vtDEW98rDUdpXqfv

And to learn more about compliant mechanisms, I recommend this video or this video.