3-D prototyping printer?

I remember seeing a web page describing a process that deposited (sprayed?) material (plastic?) to build up a CAD design so that in the end you have a 3-D prototype of your design.
Basically, a CNC machine that adds material, not takes it away.
Can someone point me to a web reference of this type of machine?
Thanks, Dave

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There are MANY different such machines, and they produce imperfect parts with different characteristics.
Basic methods are--
SLA - stereolithography, where a laser polymerizes a liquid and it emerges from a bath of liquid like the creature from the black lagoon
FDM - fused deposition modelling- sort of an automated glue gun lays down layers. Eg. Stratsys.
LOM - laminated object manufacturing- a roll of plastic is cut with an automated knife to create layers of the end product
SLS - Selective laser sintering (of powder). This has been combined with inkjet color printing to produce colorful 3-D object. Metal powder is possible.
Google for "Rapid Prototyping" and you'll find more info, machines, service bureaus etc.
Part finish and material bulk characteristics are rather inferior to solid material in every sense (strength, porosity etc.) and it's possible to make structures that are not machinable and not injection moldable (eg. with complex internal voids etc.).
If you don't mind doing a bit of work afterward (polishing, drilling, filing, painting etc) you can get a fairly good idea of what an injection molded part will look like before spending the money for a mold-- even demonstrate functional prototypes at trade shows etc. Ideal for 'industrial engineers' interested in cool sculptured shapes etc.
I'm currently using several different methods (through service bureaus) to create small quantities of plastic and metal parts for high tech applications. I do the modelling in Solidworks, output an STL file, send it off, and parts arrive by courier in a bit.

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Ah. Google is so much more efficient when you have the right terminology :-) Thanks, SP!

On Tue, 03 Nov 2009 15:05:46 -0500, Spehro Pefhany wrote:
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You often don't need to go through the finishing steps if all you want to do is fit checks or ergonomic studies.
I've seen the FDM stuff done in wax, and thought it'd be great way to do one-off metal parts if you could just use it as the wax for investment casting.

Tim Wescott wrote, On 11/3/2009 3:45 PM:
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It is already available. The model along with gates, sprue, and vents are made using an SLS or a ThermoJet rapid prototyping machine.
<http://www.vistatek.com/capabilities_mc_icp.html <http://investment-casting-prototypes.harvest-tech.com/investment_casting_prototypes.htm

Tim Wescott wrote, On 11/3/2009 3:45 PM:
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It is already available. The model along with gates, sprue, and vents are made using an SLS or a ThermoJet rapid prototyping machine.
<http://www.vistatek.com/capabilities_mc_icp.html <http://investment-casting-prototypes.harvest-tech.com/investment_casting_prototypes.htm

wrote:
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To choose the best method,look for methods with same synchretic backgrounds

    --Ifyawanna roll your own there are several open-source stereolith projects in the wild. Check out reprap.org for one and there's another over at makezine.com

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One particular project I find really exciting (on my list of things to do, when all the current projects are finally completed) is reprap.org

Joe Pfeiffer wrote:
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You could join this yahoo group... diy_3d_printing_and_fabrication /mark

DaveC wrote:
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At the other end of the spectrum from DIY home stereolithography,
http://www.msnbc.msn.com/id/33626447/ns/technology_and_science-space /
Space explorers have yet to get their hands on the replicator of "Star Trek" to create anything they might require. But NASA has developed a technology that could enable lunar colonists to carry out on-site manufacturing on the moon, or allow future astronauts to create critical spare parts during the long trip to Mars.
The method, called electron beam freeform fabrication (EBF3), uses an electron beam to melt metals and build objects layer by layer. Such an approach already promises to cut manufacturing costs for the aerospace industry, and could pioneer development of new materials. It has also thrilled astronauts on the International Space Station by dangling the possibility of designing new tools or objects, researchers said.

On Sat, 14 Nov 2009 09:38:17 -0800 (PST), iman way
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<snip> ------------------ see http://www.objet.com /
I had enquired: "In the case of your product, I raised the question about using the generated model as a ram EDM form after vacuum metalizing or possibly using a conductive/graphite loaded matrix material.
I can also see easy core production for plaster casting, either directly for low volume/prototype or for the waxes for investment casting, including quick calculation of the shrink factors by scaling the cartoon.
I would love to have one for my shop. What do the machines start at, and how much is a resin cartridge?
Anyone operating a service shop where you can email the cartoon in DWG/IGES etc. and get a part back?
In part their response was:
i Again,
I heard back from Gerry, one of our application engineers. Our current customers can use any CAD software that will output a STL file. Once in STL form - the files can be attached to our software and printed on our machines.
As for service bureaus, there are plenty out there. I have sent this email to Kirby Quirk, our sales rep out in your area. He can connect you with a shop that has the ability to print your parts with our printers.
Again, if there is anything you need, please do not hesitate to give me a call (978-495-5542) or shoot me out an email snipped-for-privacy@objet.com
Thanks and I'll talk to you soon!
Rich __________________________ Richard Wolff Inside Sales Representative Objet Geometries, Inc. 5 Fortune Drive Billerica, Ma 01821 Phone: 978-495-5542 Fax: 866-676-1533 Email: snipped-for-privacy@objet.com Visit us at: www.Objet.com
Their email is now a little dated [13 Nov 2008] so Mr. Wolff may no longer be there.

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the 3D PRINER WAS INSPIRED TO CHINESE GODS,BY CORTEZ

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You can also build your own:
http://fabathome.org/wiki/index.php?title=Main_Page
Doug White

if your in the UK this months model engineers workshop has an article on the machine. Bri
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donkey1 wrote:
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Here's another article:
http://www.wired.com/design/2012/07/3-d-printers-that-dont-suck /