The second objective for this week was to design and 3D print an object that cannot be made subtractively. I highly enjoyed this assignment because it allowed me to think creatively, develop an idea, and then turn that idean into reality - in the span of a week. Since the objective was to design something that could not be made subtractively, I thought I would design some structure that is trapped inside a larger structure. I was considering several ideas about the shapes, whether they should differ, and whether the internal structure should be free to move inside the external. Initially I was thinking about designing the shadow of a 4D hypercube. But while designing this concept in SolidWorks, I figured a way to designing a 3D printable object in such a way that the internal structure is free to move inside the external. So I ended up designing a sculpture consisting of a cube inside a larger cube inside an even larger cube - where the two internal cubes are free to move. of a way to make but while working towards that designing, I chose to make a structure consisting of 3 cubes one inside the other. I modeled the aseembly in SolidWorks and orented the cubes such that that they are all in contact with one another at the vertical vertex.
I knew that 3D printing the structure on a Makerbot or Ultimaker would be challenging, especially because the internal cubes would be held at only one point during the printing process. The potential for the internal cube(s) collapsing was very high. But I decided to try, and if it did not work, I was going to send the file to one of the other kinds of printers.
My intuition was that I could avoid the potential collapse by setting the vertical resolution to a high level, so that that mass difference between the different sides of the structure will be as little as possible during the printing process. The results were catastrophic.
After seeing those results, I reasoned that perhaps at the high resolution the head of the printer comes in direct contact with the structure and applies a shier stress, and thus causing the part to collapse. After this realization, I tried the opposite approach. I set the vertical resolution to a low level and tried printing the part again. This was going to lead to a greater mass difference between the sides of the structure during the printing process, but now the shear would be less. This method worked and the part was printed successfuly. Since the cubes were attached to one another only at two points, those points were easily proken off afterwards, enabling the internal cubes to be moved inside the external ones.