3D Printing At Discovery Charter School – Part 10

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By David Lewis

As the summer vacation winds down, the crew in the lab is expanding their skills and experimenting with some new ideas and items to “print” with the Rapman. It is worth noting that the Rapman is holding up really well under what I think of as fairly heavy use (6-8 hours a day 3-4 days a week) as the kids try new things. In the last two weeks they have taken on the concepts of:

  • Finish
  • Working from imported files
  • Printing integrated objects
  • Creating jewelry


A Finer Finish

Vernon decided to experiment with fills and finish in an attempt to achieve a strong and smooth finish. Using SolidWorks he up-scaled the mini-mug and adjusted the extrusion rate, temperature & print speed until he got something he was basically satisfied with. The mug is 5 cm high & 4.5 cm in diameter with a wall thickness of 4 mm – it is really strong.

Vernon also specified a straight seam on the cup (barely visible in the picture on the right) which seems to have helped improve the overall finish. Yes, it is beverage tight.


Working from Imported Files

True prototype shops are in the business of importing a customer’s file and developing a real object based on it. The kids have been struggling hard to make this a reality with their first project from one of the engineering managers I work with. Here is a shot of the SolidWorks file form which they are working & their first pass at a ¼ scale cutaway shell:

While the first work is clearly recognizable as the ion source shell, the accuracy, precision & finish leave a lot to work on. The Herd is learning about persistence and problem solving as they move forward. Thankfully my partners at work are highly amused and supportive of the kid’s efforts and provide a ton of encouragement. The Herd will continue to refine and enlarge the work with the final goal being a compete cutaway of the source with each component printed in a different color ABS and being removable.


An Integrated Object?

As I lack the technical vocabulary to describe this next item, I call it an integrated object. The triangular box is printed around the square frame is in free to spin (somewhat) and slide on the edge of the frame to which it is attached.

This required that the team figure out how they could raise the frame high enough off the bed that it would print independently of the box. While the fit & finish is rather rough, they were able to solve the problem and print the item as an integrated yet movable object. It is a lot of fun to watch them sort out the problems on their and I have to restrain myself from offering solutions to them.


Rings & Such

There was a recent article in the MakerBot blog about printing engagement rings and the like. The Herd instantly jumped on this as a challenge since anything that a MakerBot could do, a Rapman could do better! I loaned them my wedding ring so they could understand some of the human factors issues like having a nice radius on the edges and off they went on a goal of printing a ring that had the school initials on it. They came up with two very different versions.

The first ring is standard design with pierced lettering. The team had to figure out what size lettering would work and how to adjust the settings so that it printed cleanly. The result was some pretty crisp numbers (I have no idea what they mean) and a decent overall finish. The second ring was really creative.

This “double-ring” features a raised DCS logo and a nice two finger fitment. Both the inside and outside of the ring are fully “filleted” to provide the most comfortable fit. Once again the final finish needs a little work, but it is a neat example of what can be done. It was noted that this looks remarkably like the beginnings of a set of plastic “knuckles” and the ABS is hard enough that getting hit with this ring is indeed rather painful. These are the joys of working with a group of 13-year-olds.

Stay tuned for more of our adventures and if you have suggestions, please drop me a line at Rileys_Dad@yahoo.com

Part 11 >>