Tools

3D printing in glass

The Solheim Rapid Prototyping lab at the University of Washington was in the news last March for developing a new 3D printing process that uses ceramic powder as an inexpensive alternative to the pricier substrates that are currently the de facto standard for powder-bed processes. Well they’ve done it again, this time with 20 micron glass powder, which is formed into an object by layerwise application of a liquid binder. When the part is complete, it can be sintered in a kiln to produce a continuous glass part. The official UW online press release includes a telling quote from lab co-director Mark Ganter: “It became clear that if we could get a material into powder form at about 20 microns we could print just about anything.”

Make: Projects – “Pepakura-cast” metal pyramid puzzle

Make: Projects – “Pepakura-cast” metal pyramid puzzle

The idea of a hollow card or paper form buried in plain sand as a sacrificial mold for poured metal parts interested me. As the internet papercraft explosion has taught us, paper is really not a bad medium for 3D design, especially for the cost. Software like Pepakura will convert any 3D digital model into a papercraft one that can be printed out, cut out, folded up, and glued or taped together to make a reasonably accurate real-world replica of the original. What if, instead of using the paper as a positive representation, one were to use it simply as a negative space–a volume, supported by dry sand, that would survive just long enough to impart its form to molten metal poured inside?

As a first experiment, I designed a paper template for the pieces of a classic put-together puzzle often called “The Four Piece Pyramid.” The challenge is to use the four identical pieces to form a symmetrical three-sided pyramid. I chose this as form, first, because I think the puzzle is elegant; second, because all four pieces are identical so only one template design is required; and three, because the pieces are fairly simple, geometrically, and thus so are the templates.