It was decided to begin the project by building a RepRap printer. The main purposes of the RepRap project are to build a simple inexpensive printer that can manufacture most of its own parts. The project could make 3D printing technology much more accessible to small companies and individuals in the future.
The RepRap uses a heated metal nozzle to produce thin plastic filaments. These filaments are positioned using a Cartesian robot driven by three stepper motors. The plastic is deposited in thin layers, progressing from the bottom to the top of the printed object.
The Cartesian robot has been completed and is able to precisely position the extruder nozzle. The extruder has been built but still has some problems. Adding better insulation may help the extruder to maintain a higher temperature to extrude material more quickly. Currently, the extruder filament sometimes curls and sticks to the nozzle, causing uneven patches in the extruded object.
The image below shows the results from attempting to extrude a rectangle. As can be seen, further work is needed to ensure consistent filament width and to avoid beading caused by nozzle sticking.
The most important goal at the moment is to improve extruder reliability to accurately print objects. It is believed that increasing nozzle temperature alone could provide significant improvements. In addition, experiments may be conducted with different nozzle shapes and materials to determine the effects on filament curling.
Our other main goals at the moment are to produce a prototype support material extruder and to help improve the RepRap software. A support material extruder could allow the printing of more complex objects. Work on the software could make printer calibration easier and more intuitive. Improvements could also be made in the way the software controls the printer movements.
A tentative deadline to complete these goals is the end of the fall semester. A more complete work schedule will be established as new students are recruited and the projects finalized.
We would like to thank the Shanahan Endowed Student-Directed Projects Fund for making this project possible. We would also like to thank Dean Cave for his assistance with the project. We would like to thank all the students who have already contributed to organization and construction of the project. Among these are Jason Choi ’08, Martin Hunt ’08, Chris Pong ’08, Elton Wong ’08, Jeff Rubinstein ’08, and Vicki Chen ’09. The project will be led this year by Ian Bullock ’10 and Jason Kang ’11.
