Shapeways is deeply invested in 3D design and printing education, so we were delighted to find that one of Shapeways Magazine’s contributors, Michael Parker, is just as invested. Here, he tells us about a novel approach to teaching engineering using 3D printers.
This summer, I had the opportunity to teach a three-day workshop, Understanding the Technology of Additive Manufacturing, to students at New York City College of Technology, better known as City Tech, in downtown Brooklyn.
The students, who ranged from first-years to graduating engineers, received a small stipend if they completed my workshop, plus two more workshops: NASA Free-From Fabrication and Additive Manufacturing for Aerospace and Medical Applications. Together, they added up to City Tech’s Summer STEM Research Experience, a program funded by $1.3M in STEM grants from the National Science Foundation (NSF) and NASA, raised by Gaffar Gailani of City Tech’s mechanical engineering and industrial design technology department.
The summer students were probably expecting a dry lecture, but I wouldn’t do that to them. Not only are lectures boring, but they are poor preparation for the realities of working with the kinds of complex mechanical systems they hope to see throughout their careers.
So instead, I decided they would assemble a 3D printer from a kit. A RepRap open-source printer would be a good fit for engineering students. Due to budgetary and time constraints, I went with the HicTop 3DP-11-ATL, a Prusa i3 clone.
The workshop didn’t start smoothly. At the start of day one, only four of the six 3D printer kits had arrived. Still, I was determined to keep my introductory remarks short before launching the students into the build, where they could learn about the technology as they went.
Even engineering students rarely get opportunities to be hands-on with equipment, so I had to teach them to use their hands and eyes. We also used a variety of tools, but sometimes tools can be crutches and you can lean too heavily upon them. A tool can become inaccurate, but your eyes don’t lie. One key was making sure the students took extra care when assembling the aluminum extrusions that they were at 90° angles and flush. If you don’t have a solid base, you will run into a multitude of problems going forward.
By midday, the two wayward 3D printers kits had arrived. We completed the y-axis assembly and much of the z-axis assembly, including the bottom frame, bed carriage and main board installation. And with practice, students were able to see at a glance whether their builds were true or askew.
On Day 2, the students continued to assembling the frame, mounting stepper motors and making sure that the linear bearings were moved easily along the smooth rods. Then came one of the most critical parts: the extruder.
The extruder consists of a stepper motor that drives a gear to propel plastic filament into the hotend. The hotend barrel is meant to keep the filament cool until it reaches the heating block. The heating block melts the filament, which flows out of the nozzle and cools almost immediately. There are also fans to cool both the hotend barrel and the extruded filament.
On the third day, I made my students take apart their extruders that they had worked so diligently on the day before in order to upgrade them. The 3D printed extruder parts that came with the kits weren’t very sturdy, and the benefit of building this type of printer is that you can modify it to your heart’s content. A well-built and calibrated kit printer can rival an out-of-the-box 3D printer costing thousands of dollars more. It just takes elbow grease and persistence.
The students took ownership of their builds by experimenting with how to level the print beds, adjust the auto-level probe, and make test prints. Then came a quiz about additive manufacturing and 3D printer assembly. The four students with the highest scores on the quiz each took a 3D printer home while the other two stayed at City Tech, where any engineering students can use them.