3d rapid prototyping - Page 2

island911 · 08-30-2007, 08:04 AM

Quote:

Originally Posted by HardDrive

Got it.

So why is adding material better than taking a block of existing material and removing the excess to reveal the shape?

What Matt (onewhippedpuppy) says has some truth to it, but in actuality, any part expected to be mass produced won't have those closed-in geometries. That is, if it can be molded, it can be machined. (or at least the mold can be machined)

The advantages that I see in these layering RP machines are, first and foremost, the easy of set-up. That is, you don't have to be a machinist make a part with one of these machines. Secondly, you don't have to source a big block of material. Those RP machines are like easy-bake ovens ...or a copy machine w/ toner. You have a vat of material. ...the part made uses only the volume of material of the part --not of a block-- so , little is wasted.

The major downside tho, is the materials of RP machines. The parts are often fragile, when made somewhat accurate ... and fairly in-accurate if made from the stronger materials.

The laser sintered metals (SLS) are pretty cool in that you could make, say a wheel that looked just like a Fuchs (in whatever size you wanted.) It would be metal, heavy, have a worse surface finish and weaker than even gravity cast aluminum.

...but at least it's expensive.

onewhippedpuppy · 08-30-2007, 08:09 AM

Very true, but it is cool in that it can simulate multiple parts joined together, but created in a single prototype.

lyon · lyon's Garage

This is my first RP, I am using Redeye RPM from Stratasys out of MPLS MN. Nice folks to deal with. I am excited to get my project next week.
I can see so much potential in this process, since I am a sculptor, this will allow me to make some amazing stuff in the future. 3D scanners have also peaked my interest. The ability to scan one of my sculptures and then mass around with a 3d model will be a lot of fun.
I want to try and make a set of H4 repros for my 911, when I get some extra time and cash, maybe produce them in Kevlar or some other lightweight material.

island911 · 08-30-2007, 08:57 AM

I've had a 3-D scanner for years. Let me strongly suggest you not mess around with digitizing your sculptures. It's a real PITA to get a 3D model of swoopy surfaces that can be 'played with.'

...It's one of those things that sounds cooler than it actually works out to be.

lyon · lyon's Garage

http://www.zcorp.com/products/zscanner700.asp?ID=1
This one claims to be pretty accurate. I am having trouble believing what I see in the demo video, but I would like to try it out.

island911 · 08-30-2007, 09:02 AM

btw, here's is an example of a 911 motor I digitized a few years ago.

That swoopy engine shroud took the most time.

island911 · 08-30-2007, 09:07 AM

Quote:

Originally Posted by lyon

http://www.zcorp.com/products/zscanner700.asp?ID=1
This one claims to be pretty accurate. I am having trouble believing what I see ....

THose accuracy claims; you've got to ask "over what distance is that accuracy?" Note 5axis' link. They have to have real accuracy for their customers. ...they use a digitizing arm.

lyon · lyon's Garage

wow, nice work man. Did you make any RP parts from that?

island911 · 08-30-2007, 09:12 AM

nah, too many other (paying) projects.

onewhippedpuppy · 08-30-2007, 09:22 AM

Island, nicely done. What program?

sammyg2 · 09:46 AM

Here's a few links that show what kind of parts we made and examples of the 3D plaster casting pieces and also the fero arm I used. You can see that trying to machine something like a centrifugal impeller from a solid billet would be nearly impossible or at least very impractical.

http://www.sturm-inc.com/PortalData/16/Resources/brochures/PatternDevelopment_.pdf
http://www.sturm-inc.com/PortalData/16/Resources/brochures/Engineering.pdf
http://www.sturm-inc.com/PortalData/16/Resources/brochures/QualityAssurance.pdf

I have a couple of those plaster 3D printed patterns in my desk, one is a bolt complete with nut and they screw together very well. The other is a ball bearing complete with inner and outer race and balls. It spins just like a real metal bearing. The tolerances they can hold during the printing process are really amazing.

5axis · 10:01 AM

Quote:

Originally Posted by island911

I've had a 3-D scanner for years. Let me strongly suggest you not mess around with digitizing your sculptures. It's a real PITA to get a 3D model of swoopy surfaces that can be 'played with.'

...It's one of those things that sounds cooler than it actually works out to be.

You should check out that Atos system. It is really pretty sweet. From a machining standpoint I would say that it is usually within 0.002

I would say it works out cooler than it sounds. Lots of nerd talk.

lyon · lyon's Garage

I took a look at th ATOS system online http://www.capture3d.com/products-ATOS.html
I like what I see. What is the name of that milling machine? It looks really cool, is that Aluminum?

morganb · morganb's Garage

Last Company I worked for in China could make parts up to about 2 foot by 2 foot. Not sure if there is any limits on the size of the machines. One great advantage is any shape, even hollows can be made. Great stuff for prototypes and one offs.

island911 · 08-30-2007, 08:43 PM

Yeah, the full scan things are cool, but the problem is all that info, all that massive info, is not easily converted clean surface data. (and then 'solid" data) Some improvements have been made recently ...but still lacking, IMO.

I'm not saying it's useless (or close). Just that for a sculptor, I would suggest waiting for this technology to become more mature before spending too much time fussing with it . .. chasing what you expect it should do for ya.

oh, and the above was done with a MicroScribe (arm) various engineering measuring tools, SolidWorks (CAD). engine and parts borrowed from John Walkers Workshop.

onewhippedpuppy · 08-31-2007, 05:32 AM

I would have guessed CATIA, so I was close.

5axis · 08-31-2007, 06:14 AM

Quote:

Originally Posted by island911

Yeah, the full scan things are cool, but the problem is all that info, all that massive info, is not easily converted clean surface data. (and then 'solid" data) Some improvements have been made recently ...but still lacking, IMO.

right on

about the massive info, the tiangle files are friken huge. We often mix in regular surface models when making changes to existing items. I have not had any experience with converting them to something more tidy. That is not really a issue in my type of work. I do trust the scans much more than our ferro arm (boat anchor).

This technology is really pretty cool stuff and it is only getting better. (until the chinese rip it off and resell it at $0.25/1.00)

and that is a whole nother issue

lyon · lyon's Garage

I am really loving the RP, the first three projects I have worked on have increased my profit margins substantially......

DARISC · 11-14-2007, 10:42 PM

Quote:

Originally Posted by HardDrive

So why is adding material better than taking a block of existing material and removing the excess to reveal the shape?

The operative word is "prototype". The stl prototypes, when finally approved, are generally used to make molds for casting, as a model for parts to be machinined, or as a visualization tool for whichever process is most amenable to the number of parts to be produced. To produce a thousand parts using stl would most likely be cost prohibitive compared to alternatives and the media applicable to the process is limited. Unless things have changed recently, that's my understanding.

kach22i · kach22i's Garage

Great thread guys, I'll have to re-read it when I have more time.