More 3D Printed Metal! Lost PLA

Between Makerfaire NY, shipping and ordering filament, I haven't had a lot of time to update the blog lately, but we've been doing some really cool work. So, I'm taking a quick break just to toss up some pics of castings. Here is a customer job we worked on a while back.  They just launched their product at bowanddrape.com, so we are now free to show off the work. The product is a kissing elephant belt buckle.  The two elephants clasp together at their feet.  The customer provided the STL model for this project. It's a pretty neat project that was quite a challenge both as a FFF 3D print and as a casting. Here is a screenshot of the model.   elcap If you are familiar with FFF 3D printing, you'll probably see some of the challenges with this part.
  • Decent amount of surface detail so upright print is ideal
  • Overhangs everywhere
  • Thin cross sections (that tail!)
I came up with what I thought was a pretty clever solution.  Set them upright but lean them back at a 45 degree angle.  Set the part about 1mm into the build plate and print with a brim.  Use auto generated support material.  This results in support material that is only on the back of the model so no issues with cleanup and still takes pretty good advantage of the z-axis resolution.  It also makes good use of  'the 45 degree rule'; FFF printing can typically handle overhangs at 45 degrees or more. Here is a picture of the parts sitting on the build plate after being printed in PLA with supports still present. 2013-07-24 06.29.26 As you can see, it worked pretty well.  For some reason, the slicer didn't think the trunk needed support, but the small amount of stringing was easy to file off. The parts were then cast into silicone bronze using the Lost PLA process.  After being cast, they were descaled and polished. Here is a pic.  Really a cool design!  The picture really doesn't do the part justice, but you can see it on the model on the Bow and Drape site. Elephants   Here's a link to a video of the belt in action:  http://vzaar.com/videos/1332766 You can see some of the challenges this part presented.  The thin tail was very difficult to fill.  Trunks were as well.  We believe that the mold may have cracked during bakeout of the PLA.  In this case, it actually added a little bit of an antique appearance.   We've since changed to a new stronger investment material.  After these parts sat for a few days, the shine dulled a bit and they had a really cool antique look. Here are a few other examples of trinkets that we've cast.  We've been really into a white bronze, also known as German Silver lately.  It polishes to a nice mirror finish, then takes on a yellow tone like white gold, then continues to whiten.  Ultimately, it has a similar appearance to sterling silver. First, more yodas.  Left is in aluminum, right is German Silver selectively polished to enhance detail. Model Source here:
Yoda - Lite - more face less robe and a bit bigger (RichRap) / CC BY-SA 3.0
2013-09-18 20.04.08 Next, another from Cerberus 333 (Perry Engel).
Maker Faire 2013 robot (big red) (cerberus333) / CC BY-NC 3.0
This model was printed in colorFabb XT then cast  in German Silver. Selectively polished.  The as-cast print has a dark scale on the surface.  The part is cleaned and then polished at the high spots only.  This highlighted some of the detail in the model like the M on the chest and the eyes. Here is the XT printed part.2013-08-24 09.32.21 Here it is cast in German Silver 2013-09-18 20.02.48 I was happy to bring this part with me to MakerFaire and present it to Perry as a thank you for all of the cool open source models he has made available!  As a quick aside, here are some pics of his awesome display at MakerFaire world congress showing off the insane amount of prints he's done.   Hope to post more from MakerFaire in the future. 2013-09-21 18.14.56 2013-09-21 18.15.07   Last, but not least is another MakerFaire mascot model.
Make Robot with Keychain/Necklace Ring (Printed_Solid) / CC BY-SA 3.0
Cast in German Silver and completely polished.  I put this guy on my badge holder and have been wearing him around work for the past week.  I like him a lot and have decided to offer a few for sale on our etsy store.  http://www.etsy.com/shop/PrintedSolid 2013-09-20 19.38.18


Matthew Gorton
Matthew Gorton

Author

Matthew Gorton is the founder of printedsolid.com. He is a mechanical / materials engineer by education and has worked as a design, process and quality engineer in the medical, electronics, and aerospace industries. He is enthusiastic about applying all he has learned through these experiences to 3D printing and sharing that with others.



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