Motorizing Optical Mounts With 3D Printing

boblackburn

Overview

As part of an ongoing effort to replace costly optomechanical equipment with 3D printed parts, this project aims to implement the ability to control the positioning of a motorized optical mount with Arduino-driven software. This goal was accomplished by using three stepper motors to control the vertical and horizontal deflection angles as well as the position of a kinematic mirror mount on the optical axis. These motors were attached via 3D printed attachments connected to two manually controlled screws situated diagonally on the mirror and to the micrometer head of a linear translation stage. These two pieces of equipment were acquired secondhand, and all three stepper motors (5V 4-phase stepper motor 28BYJ-48, 1/64 reduction gear, step angle 5.625° x 1/64) were controlled with the use of two sketches (programs) and Arduino microcontrollers. The 3D printed mounts were designed with the CAD software Fusion 360, and simultaneous control of the kinematic mirror motors was achieved using a joystick as a human interface. The complete motorized mount was tested to assess the function of all three degrees of movement. All three motors driving both the mirror’s tilt as well as the linear translation stage work as expected, with a smooth and responsive control interface. The increment of the mirror’s deflection angle was found to be 0.05° per step at a three-foot distance, measured by reflecting a collimated laser beam off the mirror to a perpendicular surface. This experiment was also used to test the system’s stability and repeatability by shifting the mirror’s tilt to its maximum and returning it to its starting position; this did not result in any observable displacement of the laser. The successful implementation of a motorized mirror mount with three axes of movement for less than 150 USD demonstrates the capability of 3D printing technologies to create complex optical systems at an economic cost. The measured precision of this system is sufficient to control optical lasers/waves and suggests its potential application in interferometric experiments.

From the student

Thank you to Dr. Markus Testorf for being my mentor for the past three years. He has guided my research in the field of optics and allowed me to pursue my work successfully! Thank you to the New Hampshire Academy of Science for encouraging me to continue my investigations into engineering and supporting the development of the engineering team when it wasn't (at first) a well-established group. Lastly, thank you to my family for allowing me to pursue my interests.

From the student

Hi! My name is Bo Blackburn and I'm from Etna, New Hampshire. This is actually my fourth year at the AJAS, so I'm excited to present one more time. I was able to begin doing research for AJAS at the New Hampshire Academy of Science over the summers of 2018, 2019, 2020, and 2021 where they aim to introduce younger students to STEM before they're afraid of what they don't know. Right now, I'm the senior member of the engineering crew at NHAS and will hopefully continue to be involved!