"casting cores and molds direct from CAD"

I got an email pointing at an interesting site about sculpting
metal by a method analogous to fast-prototyping-in-plastic machines,
but in stainless steel + bronze. See link to exone and description
in the second half of
formatting link
.
Links from exone refer to casting cores and molds direct from CAD.
(Of course, for many molds using a CNC machine shop might be better.)
Briefly, the bathsheba page says, "work up the design using CAD
software", then at exone "the design is laid down, one layer at a
time, in stainless-steel powder held in place by a laser-activated
binder", "the whole model is built up," "extra powder is shaken off,
the piece goes into an oven, where heat drives off the binder and
fuses the steel powder", producing a "porous steel part that's about
60% dense", then the amazing part: "the stems are dipped in a crucible
of molten bronze, and capillary action causes the bronze to wick
throughout the piece" and "the end result is a composite metal that's
fully dense, with properties intermediate between steel and bronze.
It can take a polish or a patina, developing either rust (on the steel)
or verdigris (on the bronze)".
-jiw
Reply to
James Waldby
Loading thread data ...
Wow.
That dude did some serious warpage to the space-time continum.
Reply to
cavelamb himself
Metal rapid-prototyping methods have been around for a while, including one that's similar to this method, introduced by Extrude-Hone back around 2000 or so. It uses a CAD program (through STL output) to lay down the metal powder in layers, with a polymer binder, which is then sintered together into a 3D shape.
As for copper-alloy infiltration of porous PM parts, you may have some of them in your shop. B&D and DeWalt were making the bevel drive gears for their angle-head grinders that way at least as far back as 1997. And a lot of automotive parts are made the same way.
This is not to knock this particular development, but it's not really a new idea.
-- Ed Huntress
Reply to
Ed Huntress
I'm not questioning the technology.
But take another look at that art-part he made!
There is some seriously convoluted mathmatics there...
Richard
Reply to
cavelamb himself
Ha! Yes, it's pretty Mobius strips and Klein bottles, more or less. Very nice.
BTW, I see that the technology is the one I was talking about. The company is now called "Ex One." It's the old Extrude-Hone Prometal system. I took a photo of one of their seriously convoluted demo parts for _Machine Shop Guide_, I think it was, back at IMTS 2000.
-- Ed Huntress
Reply to
Ed Huntress
--Be aware that "he" is a "she"! She's quite a character too. Met her at the first Makers Faire. She's a brilliant hacker.
Reply to
steamer
OOhh, My appologies Ma'm.
Reply to
cavelamb himself
It works great, too.
I had them make some parts for me from an .stl file. It isn't a super fine finish, but it does clean up to flat metal quite nicely.
formatting link
--Winston
Reply to
Winston
How much did that cost and how big was that part (in ccm or such). Got pictures?
Nick
Reply to
Nick Mueller
I just uploaded the pix and a description. Pardon the lousy picture quality. I haven't bought a macro camera yet.
formatting link
I just checked my records. It looks like the folks at prometal.com forgot to charge my credit card. I cannot guarantee that they will make your prototypes for free but I still recommend that you upload your .stl file to them for a quote.
--Winston
Reply to
Winston
Nothing to pardon! I say thanks for taking the time. Not very smooth surface, but you say that its getting smooth very quickly. Looks a bit fuzzy.
What's their minimum charge? I didn't find it on their page.
WOW! I just saw that they do have a company in Germany.
Nick
Reply to
Nick Mueller
On the third example, I used successively finer grits of abrasive paper to bring down the back side which is flat. It turned out nice and shiny. I expect that some time with Cratex wheels would polish the concave surfaces very nicely.
My old scanner had a much deeper field of view than does my new one.
Officially U$500. but I did mention that they didn't charge me, for some reason.
I will be interested if you decide to have them make parts for you.
--Winston
Reply to
Winston
Oh, a hefty entry fee! But the prices at the artist's page gives some clue how much it costs. Minus 50% and times two for bigger runs or so. :-)
I'm not in need for that right now. I do remember that the link to the artist was posted about two years ago in RCM (and I lost the bookmark). I'm more interested in the technology and playing mind games where to use it.
Nick
Reply to
Nick Mueller
(...)
formatting link
--Winston
Reply to
Winston
I should have written "I lost and found that link again in this thread" The original posting contains it. :-)
Nick
Reply to
Nick Mueller
Now you're allowed to visit her site twice as often. :)
--Winston
Reply to
Winston
Another sculptor using exone services is Vladimir Bulatov (Russia),
formatting link
who writes: "I build a computer model to represent this mathematical idea in 3D world", "Next I apply custom algorithms to give the model nice body and organic look. I write all software I use for this process", "The file is sent to 3D printing company in California who uses state of the art technique to build real piece from thin layers of steel and bronze composite", "When I got my "green" pieces back it have rough surface. I hand polish pieces and burnish them in tumbler with stainless steel shot for about 24 hours."
-jiw
Reply to
James Waldby
That's gotta be a talented guy, to write 3D CAD software *and* create those 3D paperweights too. :)
Very cool.
--Winston
Reply to
Winston

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.