Thermal Expansion in 3D Printing Materials for Interferometric Devices

3D printed optomechanics offers a cheaper alternative to conventional machined parts with the potential for customization. Examples include the kinetic mounts, precise linear movement, and integrating sphere described by Salazar-Serrano et al (2017). When considering the use of 3D printed parts to make high precision interferometric instruments, thermal expansion becomes an important consideration. We present an inexpensive interferometric measurement of thermal expansion in 3D printed materials. Tests are performed with ABS and PLA plastics. We also explore variation with different colors of the plastics and different printing conditions. Finally, we present a design for a low-cost, 3D printed scanning Fabry-Perot interferometer with minimal thermal sensitivity and an anticipated finesse of about 50.