My name is Diana and I am a current mechanical engineering junior at Massachusetts Institute of Technology (MIT). This past summer, I was an intern with RepRapBCN where I helped with the design and development of the new BCN3D+ printer.
My first task was to familiarize myself with their first printer, the BCN3D, and modify existing pieces for better production quality. From there arose one my major tasks of the summer: design the new LCD housing for the new version of the printer.
A new casing for the LCD was necessary for two major reasons: 1. The LCD used in the printer was going to be changed to the “Full Graphic Smart Controller” to allow for a more straightforward and easy to use screen, and 2. Cost needed to be reduced to drive down overall costs of the machine for users.
Figure 1: LCD in casing for BCN3D printer.
Initially, the whole casing was going to be made out of sheet metal because it would drastically reduce cost of manufacturing as compared to the black custom-ordered casing used in the BCN3D printer. The idea was for the sheet metal to be cut and bent as shown in the figure below, but the idea fell through because the metal bending processes could not provide us with the accuracy needed on the angles.
Figure 2: Proposed all sheet metal casing design.
In an effort to keep cost of the casing down, yet have a fast and reliable production method for the casing, I started playing around with new ideas, one of which incorporated the use of sheet metal and RepRap printable parts. This new casing initially involved three major pieces: the front sheet metal piece, the back sheet metal, and the RepRap printed spacer that goes in between both pieces of sheet metal. After further development of the idea, the design later came to include a support piece to help the assembly withstand the forces exerted by the user while interacting with the LCD, as well as a couple of printable buttons.
Figure 3: Left: First prototype of the casing. Made completely out of ABS with the BCN3D printer. Right: First prototype with sheet metal pieces and printed spacer.
Once the prototypes were made, I checked the design, dimensions, and tolerances of the assembly with the team to make sure the case fit well with the new LCD. The casing was approved, but I was asked to add flow to the design…
Flow?!? I had no idea what they meant by that, but had a pretty interesting time trying to figure out what it was. I finally understood it to mean that the design was “a square”, both literally and figuratively, as in it was boring, and I was supposed to fix it. However, I didn’t figure that out until after I had played with the design.
Figure 4: My search for ‘flow’
Even though I finally came up with a design that had just enough flow, I’m not sure I ever completely understood what it meant, but I had a lot of fun using the new word. Some of the guys at work definitely made fun of me for not knowing what it meant, but hey, I had never heard it back in the US, either in Boston or California.
It was really fun and a great learning experience to work with the RepRapBCN team over the summer. They’re a quirky, passionate, and hard-working group of individuals and I really enjoyed being a part of the whole design process for the new printer that you all see and love today. In the end, after working on other smaller projects for the printer, inadvertently teaching my supervisor Spanglish (which he didn’t like), trying to understand Catalan and learning small phrases here and there like ¿pot repetir en castella?, and getting used to the work culture of Spain, the LCD housing was finished! It was a fun experience overall and I hope you like the new design!
Diana, MIT ‘15