Why I hate STL

[cobywan]

Here is an example of why I am no fan of STL generated parts. You can see the contour lines in this little truck. The semi is 1:200 scale. So the cab is about 1" long or so. I'm guessing that this isn't the best resolution that is available, but is very common in parts I've seen.

Edited for NDA.

 

[corranhornjje]

I think you'd be less disappointed if you understood the limitations of the medium and it's typical function and planned accordingly.

 

[cobywan]

I would never have used this for this subject. It was our client that had it done. I have never seen an STL part that was as good as hand crafting.

I do understand the reason for it. That's the whole reason these procesess are called "rapid prototyping".

There's a great old addage;

Good

Fast

Cheap

Pick any two.

 

[Mycroft Holmes]

Coby, you need to understand there are many tiers to SLAing. They have machines like the Viper that grow in 5mil stacks. Also, the resolution of the model vs out put is a major factor. Don't blame the medium for the research you need to do in getting the out putted results you require. There are multiple new mediums like Polyjet for real fine and thin details. And now there is SLA ABS.

I have grown MANY things from studio files and you just need to shop and research what out put results you want and match them with the company that has the capabilities.

Try these people: http://www.stratasys.com/default.aspx

We're using them for several projects you will here about soon.


Mark

 

[Kuhn Global]

<div class='quotetop'>QUOTE(Mycroft Holmes @ Nov 28 2006, 01:24 PM) [snapback]1367154[/snapback]</div>

Coby, you need to understand there are many tiers to SLAing. They have machines like the Viper that grow in 5mil stacks. Also, the resolution of the model vs out put is a major factor. Don't blame the medium for the research you need to do in getting the out putted results you require. There are multiple new mediums like Polyjet for real fine and thin details. And now there is SLA ABS.

I have grown MANY things from studio files and you just need to shop and research what out put results you want and match them with the company that has the capabilities.

Try these people: http://www.stratasys.com/default.aspx

We're using them for several projects you will here about soon.


Mark
[/b]

Interesting Mark.

From what I looked at, the largest plate area was 24x20x24. I am not trying to stray from Coby's subject, but how much does one of these machines run?

 

[Commander Max]

Kurt, I can answer this question.
For an stereo lithography machine they start at about $60,000.

 

[cobywan]

It's totally on subject.

The mesh quality is all you can controll as a pattern maker. (That's why I use NURBS to do my modeling. You controll mesh density at output or you can send an IGES file out directly and have whatever machine you use set it's resolution to what you nee.) I believe that wire EDM is the finest quality CNC you can get.

Please show me some parts that I would find acceptable without cleanup and I'll go to them for work.

The best I've seen so far is a wax printer. Truth be told there is just no time for me to find an outsource service for one to two jobs year that can be done inhouse. (Basically the timeframes we get are too short to have someone grow a part and mail it to us.)

I'm just saying that I have never seen a part in hand that was any better than what I showed in my first post.

Please, PLEASE show me wrong. I would love to be able to get this stuff done better and faster.

 

[Commander Max]

<div class='quotetop'>QUOTE(cobywan @ Nov 28 2006, 04:19 PM) [snapback]1367244[/snapback]</div>

It's totally on subject.

The mesh quality is all you can controll as a pattern maker. (That's why I use NURBS to do my modeling. You controll mesh density at output or you can send an IGES file out directly and have whatever machine you use set it's resolution to what you nee.) I believe that wire EDM is the finest quality CNC you can get.

Please show me some parts that I would find acceptable without cleanup and I'll go to them for work.

The best I've seen so far is a wax printer. Truth be told there is just no time for me to find an outsource service for one to two jobs year that can be done inhouse. (Basically the timeframes we get are too short to have someone grow a part and mail it to us.)

I'm just saying that I have never seen a part in hand that was any better than what I showed in my first post.

Please, PLEASE show me wrong. I would love to be able to get this stuff done better and faster.
[/b]

Cobywan,
The best I saw was a $500,000+ machine. It was at a local shop here in Phoenix. I don't remember the make.
I have a 3D printer, and have similar issues. At this time I don't think there is any way around part clean-up.
My machine surprises me at times, I still have to fix(add resins or CAs) the parts.
For some designs it does beat scratch building, but not all.
I think the technology is still in it's early stages, we haven't seen anything yet.
The only problem is once the high quality machines come out, everybody will have one, eventually.

 

[Kuhn Global]

<div class='quotetop'>QUOTE(Atemylunch @ Nov 28 2006, 03:13 PM) [snapback]1367241[/snapback]</div>

Kurt, I can answer this question.
For an stereo lithography machine they start at about $60,000.
[/b]

60K eh? Hmmmmmm LOL

Thanks Atemylunch. LOL... I understand Richard sent something LARGE to you today. LOL.. enjoy it dude. I hope to see you build it soon.

Coby,.. thanks for starting this subject... it is interesting to say the least.

 

[cobywan]

It's not studio scale OR cgi.

I really imagine that this subject could get just as heated as that one did.

I honestly do need to find some local service for some of this stuff. I have a project right now that's kind of a pain. I have to turn four rings with a bean like cross section. I'm not a lathe guy. It's definately a part that RP would be great for. I would have no problem dealing with the cleanup. The only problem is that we have a budget of 8 hours to do them. (I don't know what the shop charges per hour do there's no practical value to that statement.)

I'll be grinding a custom tool for the thing sometime this week.

 

[minieffects]

Well I have to say that my expeirence with rapid prototyping is great. Ive been using it for several years now and its bailed me out on many shows. The particular machine I used was a 3d printer that uses wax. The nice plus with the wax is you can take alcohol and smooth out any lines. But to be honest I have found a coat of primer on the part before molding does the trick.
This machine was responsable for generating all of the parts for the 6th day foosh guns, the Van Helsing cross bow, grapple gun and pistol as well as many parts for Minority Report. I also had miniature parts grown for Reign of Fire for the burned out Parliment Building and Big Ben and there is no way we could have gotten the detail that we did in the time we had if we had to do everything by hand. The beauty is you can either pull a silicone mold or send the parts out and have them investment cast out of what ever metal needed. My recomdation is to do the research, and if you are modeling the parts in Rhino or Solidworks or any other 3d program that you are exporting the stl file out at the desired resolution. I have had sla parts come back to the shop, get primered and thrown into rubber, no problems. You do of course have to sometimes deal with other peoples files, and they may not fully understand the process. This has happend to me on many jobs and I have had to go back and remodel the part just so it would look good.
There is a learning curve so dont get discouraged, its a wonderfull tool to add to your toolbox so to speak so give it a chance. Remember, your cell phone, pda, tv remote and much more was probably rapid prototyped at some point. Its not the final solution to all problems but when applied correctly its a wonerfull tool.

Here are some vendors I have used in the past.

These guys have even devolped a machine that can grow metal. Its really cool.
http://solidconcepts.com/

These guys are really cool and know their stuff.
http://www.gentlegiantstudios.com/

Hope all this helps

minieffects

 

[cobywan]

Thanks for the links guys.

Here's that wax process I saw over at Sci-fi Meshes;

http://www.scifi-meshes.com/forums/3d-wips...sporter-79.html

http://img151.imageshack.us/img151/7702/eagleday50555oz7.jpg

http://www.scifi-meshes.com/forums/3d-wips...sporter-52.html

And here's the part generation in process;

http://www.scifi-meshes.com/forums/3d-wips...sporter-49.html

I asked for a product pamphlet for the printer but it never arrived. I'll have to look it up again. The nice thing is that the local toy company Wizkids has one. I might have to see if they will do small jobs. (I was seriously considering having it done for the details on the Galactica's top engine deck. I've been OK avoiding it with laser cutting and hand work.)

 

[Commander Max]

Solid concepts is using the same machine I saw.
Selective Laser Sintering from 3d systems.
It's wild to watch. It uses a laser to cure the media.
Like everything else it's slow. Then it does build .004" at a time.
Same as my 3D printer. It builds an inch an hour.

I have the ZPrinter 310 Plus from Zcorp.
Great little machine, I've never used anything so simple.
They have a larger format machine that prints in color.

I think the stated drawbacks are minor, when compared to the advantages.
I've been so used to designing for my machines(lathes, mills, etc.).
When I was told, "These machines can print anything."
I had a Monkey and the Monolith moment(2001ASO).
I have no desire to go beat up my neighbors with bones.
But I could print the bones, the satellites, the Space Clipper, Moonbus, Discovery....................

 

[minieffects]

The one I used at Applied Effects was a 3d systems, what great machine. I wish I had the capitol to buy or at least lease one.



minieffects

 

[Commander Max]

No kidding, Minie.
It's one thing to buy/lease the machine. It's another to afford the media, and the service contracts.

 

[Flintlock]

I had an idea for a project that would require me to get some parts printed on one of these printers, and I have made models for it in CAD. However, this is not something I've done before so I don't know what you mean when you talk about knowing the process and modeling according to that. The machine at the service I was looking at (printapart.com) said that their machine resolves at a 0.003" cube, which is definitely fine enough for the model I was making (I made it on a 0.020" grid - there are some angled surfaces but I just figured I could do some sanding when I got the part). I wanted to ask is there anything else I need to take into account with this? The parts are kind of expensive and it would be an investment, so I want to make sure I do everything right so as not to pay money for unusable parts.

I've bookmarked this thread.

 

[minieffects]

<div class='quotetop'>QUOTE(Flintlock @ Dec 1 2006, 05:58 AM) [snapback]1369377[/snapback]</div>

I had an idea for a project that would require me to get some parts printed on one of these printers, and I have made models for it in CAD. However, this is not something I've done before so I don't know what you mean when you talk about knowing the process and modeling according to that. The machine at the service I was looking at (printapart.com) said that their machine resolves at a 0.003" cube, which is definitely fine enough for the model I was making (I made it on a 0.020" grid - there are some angled surfaces but I just figured I could do some sanding when I got the part). I wanted to ask is there anything else I need to take into account with this? The parts are kind of expensive and it would be an investment, so I want to make sure I do everything right so as not to pay money for unusable parts.

I've bookmarked this thread. [/b]

My advice is to talk to the company that is doing the grow and ask them what results you can expect from your file. Just remember wherever there is an undercut or overhang most machines will put support structure in those areas. If you dont need the part solid then its a good idea to give it a thickness so the inside are is all support stucture and cuts down on the cost.

hope this helps

minieffects