As a part of the masters course Design Principles of Precision Mechanisms, I used an Ultimaker of the DesignLab to print an upscaled functional model of our final design.
The case was about a fast moving scanner mirror for directing laser light through a lens and onto a subject. A single circular mirror with a diameter of 2cm should be applied and the laser spot should be able to cover an area of 30 degrees in both directions. This should be achieved with a maximum velocity of 5000rad/s and an accuracy of 2μrad. Therefore, six degrees of freedom should either be constraint carefully, or actuated. Since two rotations are desired, the three translations and remaining rotation were constraint. The translations were constraint by applying three wire flexures that virtually come together at the center of the surface of the mirror. The two rotations are achieved by applying magnetic actuators, simplified as the four blocks. These actuators are placed in such a way that the center of mass is at the same spot as where the wire flexures point to.
The assembly was divided in a mirror part, three wire flexures, a base and end part, as can be seen in the image below:
They were upscaled about 2.5 times and printed simultaneously. The holes were enlarged to enable the glueless assembly of the wireflexures. The base and end part would have a thread to screw them together in reality and clamp the flextures. To simulate this clamping, the base and end part were made not to fit perfectly to illustrate this. In hindsight it would have been even more illustrative if they had fitted at all. Still, the differences in stiffnesses in all the ranslations and rotations at the center of the mirror can be felt. Rotating around the axis orthogonal to the mirror is requires the least amount of force, translation on the same axis the most.
Although the supporting material on top of the mirror was not removed (it was a “proof of concept’ model after all), the examinators were fairly impressed.
