Direct Ink Writing Extruders for Biomedical Applications

There are many 3D printing processes using various printing materials for different applications. Among these printing methods, robocasting or direct ink writing (DIW) is suitable and mostly adopted for biology and biomedical applications. DIW is an additive manufacturing technique in which a filament of 'ink' is extruded from a nozzle. The ink is usually supplied through a syringe or container and does not need to be heated to a high temperature to extrude through the nozzle for printing. Therefore, cells and bacteria can survive during the printing process. The ink must have high viscosity or be gel-like to maintain the sturdy structure for the printed object before post-processing. Several professional DIW printers designed for biomedical and medical research are available in the market such as EnvisionTEC 3D-Bioplotter, however they are usually extremely expensive. Collaborating with the medical school, this project will design and build new extruding systems on a low-cost RepRap machine. One RepRap Prusa i3 printer is modified able to extrude independently two different hydro-gels dedicated to the stem cell research. The modification is expected to utilize other 3D printing methods to create parts. This is a team's Capstone Design Project with students involved to promote and extend the applications of 3D printing. Student working processes of design, hardware modification, as well as testing procedures will be observed and recorded. The project activities, the testing results, and the students’ learning experiences and outcomes will be present in this paper. Student working processes of design, hardware modification, as well as programing procedures are observed and evaluated for systematic course material development.