Who here is using 3D printers to make molds? I seen some crazy things coming out of those! NASA plans on using them to make tools in space, in my opinion its the closest thing we have to teleporting.
I have used several technologies at work for rapid prototyping and mold making.
FDM (Fused deposition modeling). I have used FDM parts for a mold. The surface finish it not great, so parts don’t release well from it. The piece is built up from 0.010" diameter ABS plastic strings, so there valleys between the strings. I have successfully made some polyurethane parts from the molds.
DMLS (direct metal laser sintering). The surface finish on these parts is pretty good right out of the box. The finish is matte, and probably about the roughness of 220 grit sand paper on furfaces facing up in the machine. The surfaces facing down have a much rougher finish to them, not suitable for any sort of molding. These parts can be finish machined and then used for molds, if that is the desire. The only real advantage to this is for extremely complex geometries, etc.
I couple years ago I had a part made using rapid prototyping, I actually think it was FDM. I wet sanded it to a fine finish then epoxied it to an aluminum plate with some dowel pins pressed into it for locating. Then from that part master I poured 4 latex molds which I later used to make a bunch of cast epoxy parts. I really liked this technique and would re-use it in the future.
Holy Cow!!! Amazing!!!Nice find George!
Thanks TNT 
I want one so badly…
The VP from Z Corp in the video was on This Old House this past season. He printed a model of his entire house including the new addition.
Jump to Scene 3 in the video. http://www.thisoldhouse.com/toh/tv/video/0,,20537408,00.html
Hi MaineCarbon, where in Maine are you from?
They don’t work well, unless you use the wax with aluminum, then you have to bake it to draw the wax out and pull copper in, those would work but for less time and money just CNC a mould out…You still need a STL file to create the 3D print, so going one step to surface it and make a parametric solid so a CAM package can read it makes more sense personally.
Most CAM’s can take an STL but the 3D scan surface quality is often not good enough to use as a mould surface. We have a 3D scanner and honestly, if I take a sharpie and write something on the piece I am scanning, I pick that ink up in the scan. Every little imperfection is picked up and needs cleaning from the data.
These aren’t really big enough to make moulds but could make clips, posts, stand off, etc… Some of the small things that sometimes need to be part of your finished composite part. Although at the price of the material and time it might just be better to buy the oem parts unless you are making some one off object.
I’ve posted this one on here before and it’s print quality does not look good. (lots of stringers)
http://store.makerbot.com/replicator-404.html
Don’t know much about this one but it seems just like the makerbot.
https://shop.ultimaker.com/en/ultimaker-kits/ultimaker-kit-new.html
Then there is this one that I want to pick up. It’s about to come out in a few weeks and I trust it the most because it was made by a real 3d printing company not home brewed. From what I was told it’s made in the US just outside of DC. Plus it seems to have the best print quality which is my deciding factor in 3d printers.
http://cubify.com/
HP jumped onto the 3D printing bandwagon, with a very nice product. Most of what I have seen is extruded, which delivers a part which is more or less usable.
The powder-printing technology is nice as well, as it can make full colour products (great for architecture). However the result needs to be strengthened by dipping the part in epoxy resin, if you want to use it somewhat structurally, and the result is a bit course, not smooth.
And there is the SLA technique, where the part “grows” in a bath of liquid material. No experience with that, except for some (old) samples. There were nice, though.
Also very exciting is the DMLS (direct metal laser sintering). I don’t know if it has a great application for composites at this point.