While I swear I'm revving up to print my own stuff, I've been printing some items designed by others to get a sense of what the technology is capable of. Here I report that metal (bronze-infused stainless steel) prints have rather marvelous detail levels relative to, e.g., prints in white detail material. I show the results of a print of Rob Mack's (Mack Madness) test piece in metal, allowing comparison to his pictures for the other materials with the exception of White Glaze. I also printed the Chaos Elemental figurine from Chez Reno in metal and white detail for a side-by-side comparison.
First, the data.
The test piece in metal:
The figurine in metal and white detail material:
- For my prints, the resolution of metal printing is comparable to white detail material; details below.
- I can see daylight through 8 of the 11 circular holes in the negative test piece (top). That's more than any other material Mack printed (WSF, white detail, transparent, cream robust), where white detail managed to hold 7 of 11 holes open and WSF only did 5. See his pictures of the test pieces printed in other materials. The smallest open hole has a diameter of ~0.5 mm on a piece with a thickness of ~1.5 mm; without the input STL file I can't say what the intended measurements are (Mack?). Only 2 of the 7 rectangular holes pass light, again better than WSF (1) and comparable to white detail (2).
- Both test pieces have a bit of warp. They do not lie perfectly flat. At most 0.2mm warp on a 58.5mm piece, so quite minimal, but perhaps important for the most demanding applications.
- The nominal rectangular size of the pieces is 10 x 60mm. The prints I received are actually 0.91 x 58.5mm. Without the STL file in hand, I'm unsure whether this is an artifact of the printing or the "nominality" of the reported dimensions.
- None of the positive (protruding) solid circle/cones that I can test fit into their corresponding holes. Close, but no. This means that if you want pieces to fit without filing/sanding, you should make them slightly (who knows, but I would guess that 0.1mm would do) smaller than the hole they must fit in. Sadly, I have not yet done a fit test. But I may, soon enough.
- Because of the polishing of the metal pieces, areas close to a protruding area tend to be rough (unpolished) compared to less-sheltered areas. The inside of the figurine's mouth, for example, has a much more crystalline look.
- More on polishing: the X's on the test piece came out well compared to the other materials. Slightly raised bits, like the logo on the back of the negative test piece, were mostly obliterated by polishing, whereas the sunken stamp-like areas look quite sharp down to a fraction of a mm. I'd be very grateful if the Shapeways folks posted more details on the exact polishing process.
- Side-by-side comparisons of the Chaos Elemental figurine (which I chose for its nooks, crannies and fine details) in metal and white detail suggest that metal is again equal to or even superior to the white detail material in resolution. For example, as the photo shows, the half-millimeter saliva/jaw-membrane connections on the metal piece are perfectly rendered, whereas on the white detail piece, both are broken (it is unclear whether they failed to print or broke after production, but visually it appears to be a printing failure). Similarly, as is apparent in the rear view, the thin dewclaw on the back left leg is sharp and intact on the metal piece, but again either broken off or misprinted on the white detail piece. The teeth are ever-so-slightly better-formed in white detail, but all are present and nearly as good-looking in metal.
(A word of caution: my white-detail print seemed to not be of the highest possible quality. The rear of the skull, for example, has obvious layering that is almost flaky. However, Mack's test pieces in white detail compare with my metal prints in virtually the same way, suggesting that our prints are representative of the material and printing properties of white detail and metal.)
- The "washed out" white look on the white-detail figurine is not a photographic artifact. I'm sure many of the skin details are present on the white-detail print, but in typical home lighting, the contrast and material properties make it almost impossible to see anything but the bulk shape. In metal, the skin looks beautifully pebbly -- the material is well-suited to the model -- and also shows details like muscles and horns to full advantage.
I hope this information is useful to y'all. A final note on the emotional side. After having my expectations set by a lovely WSF print and the white-detail pieces (which arrived in 10 days versus 21 for the metal), I was astonished by the detail on the metal pieces, and spent Monday running around accosting people in the halls of Harvard, thrusting bits of metal into their faces and saying, "Can you believe this?" For the record: no, they cannot.
Huge kudos to the Shapeways folks, and the developers of the metal printing process, for this spectacular technology. I'm still giddy and amazed that we can make things using it for a price that is accessible to mortals!
p.s. -- The quarter is the work of the U.S. mint. They do metal printing at an enviable level of detail. I hope they open up their technology -- on a cubic centimeter basis it's much cheaper than Shapeways.
[Updated on: Fri, 30 October 2009 00:04 UTC]
Elytra on Shapeways: http://www.shapeways.com/shops/elytra