http://blog.makezine.com/archive/2010/06/3d_printed_skull_ring.html
In the picture, the does not look well finished. That texture that
looks like porosity, I think is actually the from the printing
process. Does anyone know?
This isn’t inherent to the process, is it?
Elaine
Not porosity…that texture is meant to be there
This isn't inherent to the process, is it?
It seems to be the printing process with this application, I have
seen better printing.
Regards Charles A.
In the picture, the does not look well finished. That texture that looks like porosity, I think is actually the from the printing process. Does anyone know? This isn't inherent to the process, is it?
The process being used for printing them is a powdered stainless with
a polymer binder that is fused by a laser to create the item. Once
the build is complete it is then sintered in a kiln which burns off
the binder and fuses the stainless like PMC but much more porous (60%
dense) due to the size of the powder used. Then the sintered item is
again heated and placed in molten bronze which is drawn into the
stainless matrix by capillary action thus filling the voids and
making it much stronger. There is a sculptor named Bathsheba Grossman
who has been using this for years in her work. She has a great
explanation on her site at
http://www.bathsheba.com/sculpt/process/index.html#3dprint
A rough surface is inherent to the process used on those rings. You
can grind and polish it but in this case it looks like the maker
just polished the surface without cutting down enough to get past the
surface roughness of the part
James Binnion
James Binnion Metal Arts
Not porosity..that texture is meant to be there
Well sort of, that texture is a partially finished surface from that
particular method of direct metal printing. It is inherent in the
process for it to have very rough surfaces. The rings next to the
shiny one are the as printed/sintered/bronze filled stainless matrix
parts before any finishing work has been done. If they could make a
better surface with that process I am sure they would. You can see
more about that particular process at
http://www.exone.com/eng/technology/x1-prometal
James Binnion
James Binnion Metal Arts
Hello Elaine
It appears to me the maker has just not cleaned up the casting very
much either because they are not very fussy or else they wanted a
fairly rustic old world or antique look to piece. 3D printing does
leave quite prominent layer lines because of the way the wax is
built upbut they are normally no problem to sand and polish away in
most casting metals. Porosity is usually not present when metal is
cast properly.
Hope this helps.
Phil W
3D printing is still in it’s infancy. Depending on the extruded
material the finish will be more - or less - smooth and there is
little control over the fine surface properties. I like it!
Tony Konrath
When it says “printed” do we know if this is printing in wax, or
printing directly to metal?If it’s wax, then the texture is there on
purpose. If they are sintered directly in metal, then the texture
could be a direct result of the process.I don’t work in rapid
prototyping myself (we use= wax milling), but I met a lady who
worked for Birmingham College as a researcher, dealing with the
problem of finishing laser sintered jewellery items. She told me that
the result were generally poor, and her task was to try different
combinations of tumbler media and chemical processes, to see what
would yield a cost effective finish.In theory, it’s a great way to
rapid prototype or even make items, but take a look at this brochure
for “direct metal laser sintering”:
http://www.3trpd.co.uk/pdf/dmls-brochure-22-09-09.pdf
Looking at that, metal sintering looks brilliant. Thing is, the blue
item on the front page of that brochure is the one I was shown by
the nice lady - and it looked NOTHING like it does in the brochure.
It was bumpy and porous, and the inside of it was even worse. They
don’t come out of the printer looking that sexy.I found the link to
that brochure by chance - I was about to use the company as evidence
of how wrong and small-minded I was being, but having seen their
best work, I’m not convinced. Eventually, we’ll be building
everything atom by atom. But we aren’t there yet. Hopefully, someone
wiser than me can correct me on this, because I want laser-sintering
to work. Just because it’s really, really cool.
I’m familiar with this process, and yes, the pits you are seeing are
inherent in the process of “printing” with those 3D resin printers.
They come out of the machine feeling very much like sandstone. But
that doesn’t mean you couldn’t step in and smooth them out in
between making the model and casting it. A hand-rubbed wax cream or
some other similar filler would certainly smooth out the model, which
would all burn out of a lost wax mold together.
The 3D printers lay down a plastic-based powder resin of sorts. Great
for outputting a somewhat rough model for casting.
The skull was prototyped directly in metal. This technique if
polished will have a por0sity to it.
That type of 3D printing gives a porous sintered steel product, that
is then filled in with bronze in a secondary process. The company
that makes the actual designs, Shapeways, will make them for most
people and is used by Bathsheba Grossman for much of her work, which
shows somewhat similar texturing.
Jason
I'm familiar with this process, and yes, the pits you are seeing are inherent in the process of "printing" with those 3D resin printers.
This ring is not done in a resin printer, it was laser printed in
stainless powder with a binder that is then sintered to fuse the
stainless. It is then infused with molten bronze to fill the pores
in the material. The surface is very rough but can be ground and
polished, that particular ring was just not finished to the point
where the surface roughness was removed.
Jim
James Binnion
James Binnion Metal Arts
When it says "printed" do we know if this is printing in wax, or printing directly to metal?If it's wax, then the texture is there on purpose. If they are sintered directly in metal, then the texture could be a direct result of the process
The ring is direct metal “printing” not wax or polymer that is then
cast
James Binnion
James Binnion Metal Arts