User-Friendly 3D Printed Colorimeter Models for Student Exploration of Instrument Design and Performance

A user-friendly set of computer-aided design (CAD) models and stereolithography (STL) files is reported for the production of simple and inexpensive 3D printed colorimeters. The designs shared here allow educators to provide active learners with tools for constructing instruments in activities aimed at exploring the technology and fundamental principles related to quantitative analysis. While previous efforts focused on fabricating inexpensive instruments from building blocks and other household items, 3D printing transcends the limitations of conventional tooling. The digital models described here are flexible in design, printed quickly, and each requires less than a dollar's worth of plastic filament. These designs are compatible with simple CAD software, such as Inventor Professional and Tinkercad, commonly available to educators and students. With the use of programs of this type, CAD files are easily modified in order to produce customized models for exploring a variety of concepts inaccessible to more conventional instruments. Developed with novice 3D printer users in mind, comprehensive slicer settings are provided to assist educators in obtaining reliable results. Once printed, the resulting colorimeter instruments perform very well when compared to commercially available spectrophotometers.