Why build a 3D printer?
I use consumer grade FDM (fused deposition modelling) 3D printers all the time at home as they can rapidly prototype parts for robots and other projects. This type of printer melts and lays down layers of plastic in a particular shape to form a part.
Consumer level FDM 3D printers are readily available and affordable but are limited to printing plastics which melt below 290°C. Industrial high temperature FDM 3D printers exist but are very expensive, so I decided to design and build my own as a challenging but fun learning experience.
How did the project come to fruition?
The project started in January, in Mr Burton’s Design Innovation class for Product Design. The printer was definitively a very creative and ambitious project, requiring a huge amount of research.
I started with research to define the different subsystems on the 3D printer (Extruders, Print Bed, Gantry, Heated Chamber, etc). Early on I had to make major decisions for the overall printer build volume (Size of largest part printable), number of extruders, kinematics, etc. I looked at other industrial 3D printer designs, from companies like Stratasys, on the market for inspiration.
The specs I settled on are two extruders with max temperature of 500°C, heated chamber with max temperature of 230°C and a vacuum hold-down bed.
After this research, I started the CAD design process. I used the CAD software Autodesk Inventor to design all the unique parts on the printer. I had to learn sheet metal design, as I had no prior experience designing folded sheet metal parts. The CAD design took most of the year to finish and the printer went through 6 major design iterations in the process. I also learnt how to do some simple CFD (computational fluid dynamics) fluid analysis and FEA (finite element analysis) to check for turbulence in the printer ducting system and static load analysis on a critical piece of the frame.
The design features over 100 unique parts I designed. Most of the metal parts were outsourced for manufacturing, but there were still plenty of other parts that I made. I spent a lot of time last year learning how to use the centre lathe at the school’s design department, where I made many round aluminium spacers for the printer. I even had to learn how to sew using the school sewing machines, though with Nomex thread (racing suit thread. Fireproof) and fibreglass fabric. I learnt many new skills during the course of the printer project as well as learning about material selection and different manufacturing processes.
I also had to source many other off-the-shelf parts and raw materials from simple screws, to heaters, tempered glass and even Teflon coated fibreglass fabric.
The assembly process was next. I had to precisely align the frame together and assemble delicate components like the extruder assembly. There was a lot of measuring and tweaking to ensure the printer frame matched the CAD model.
Overall this project was very interesting and I learnt many new things ranging from physics (venturi vacuum effect, thermal expansion) to practical skills like sewing and operating a lathe.
What’s next?
The next upcoming tasks to complete the printer are finishing the electronics and firmware, wiring, pneumatics subsystem and installing thermal insulation.
Bringing the project to completion is my goal now. Also, once completed the printer can technically bake cakes with a high precision homogeneous temperature; an incentive to finish the project sooner! I am also looking forward to when the printer starts printing parts as it will finally show the result of all my work over the past year.
