Shapeways FM switchers: Cleaning FUD

[Alwyn Cutmore]

Hi All,
It is the same with all rapid prototyping models and also the type of machine being used. I have models here of Australian N Scale locomotives that would leave that crud for dead. It depends on what you are going to pay. The guys here get the prototype printed and then the pattern is finished and polished by the company. Takes out all the lines and that is their responsibility. When the pattern is finely polished and ready it is sent to the owner who then reproduces the model by casting in a more resilient polyurethane. Rapid Prototyping is exactly that. It is designed to get an idea of the finished object from the CAD drawings so that production and die manufacturing issues can be seen before a lot of money is spent cutting a tool. It was not designed for fine finishes the likes of which modellers are expect for a good result. The only way to get a good result from items like this is to have all the flat areas printed flat and then make up the pattern from there. That way there are no elevation lines on the outside surface. Once you have the pattern to-gether it is cast in urethane. Not one of the fast cast rubbish polymers but good quality high impact stuff that will take a bit of abuse. If you want to see good models have a look at the models from Kaslo Shops. You do not throw them in the bin.

I have looked at some of the stuff coming out of Shapeways, even small detail items and they are still with the owner. You pay for what you get.

Regards

Al

[wcfn100]

I think this is also partially the fault of the artist. They should be making flat models that will only orient tray style.

Yeah, it's the artist fault.





Jason

[Dave Schneider]

Thanks Alwyn,

I appreciate your perspective. Again, I went into this with my eyes open and am not expecting perfection for $35. I was just wondering about what I was seeing and whether my wax removal process was suitable. So far, it seems like I have followed recommended practices. I will send my photo to Shapeways to see if this is within their specs for printing. I expect that it is, but I figure I should ask.

Thanks everyone for their comments.
Best wishes, Dave

[Hornwrecker]

Thanks for the info, Dave.  I still want one bad, so I'll get one anyway, once my layout redo is done eating all my funding.

(Your layout thread made me buy the Beer Line book, now on permanent loan to a MILW nut friend)

[Dave Schneider]

Thanks for the info, Dave.  I still want one bad, so I'll get one anyway, once my layout redo is done eating all my funding.

(Your layout thread made me buy the Beer Line book, now on permanent loan to a MILW nut friend)

You are welcome Bob. Happy to hear of your interest in the Beer Line. It is a very interesting bit of railroad. We do have a Yahoo group called  Beerlinemodelers for whomever is interested.

Best wishes, Dave

[Alwyn Cutmore]

Dave,

I was not having a shot at you I was more interested about informing the modeller exactly what they get. I do not have the time to sit there and polish up a model. I was also wondering how brittle the Shapeways items are. I know with some of the urethanes I use I can throw it on concrete and it wont even mark. Kaslo shops sell a Wide Cab SD50 body with all the etches and stuff for about $55.00. and it is great stuff.

Regards

Al

[mmyers05]

I think this is also partially the fault of the artist. They should be making flat models that will only orient tray style. That would leave the chassis facing (inside) rougher and the outside with much smoother, better detail.

Sure, it would take a little extra effort. Not much as you can simply splice and paste sections of a model.

That's the sort of thing that sounds easy when you say it fast.

Once you start making 'flat' models (car sides as separate pieces etc.) you start running into major strength/warping issues extremely quickly. A big part of the reason that I can design models with as little material as I do is that I design them as a single piece (so the cab roof supports the cab sides which in turn support the frame etc.) Offhand I'd guess that I'd have to double or triple the thickness of every major component to accomplish what you are describing  (can anyone say greatly increased cost?).

Also, as a designer I can't choose the build orientation. This means that Shapeways is almost undoubtedly going to print those nice flat 'sides' on edge anyway (effectively defeating the purpose).


[/quote]

Yeah, it's the artist fault.





Jason

Haha! That looks like a nice long build...

Interestingly that is something that I have never seen Shapeways do (in FUD at least).

My guess is that the model was produced cab end down. There is always some major issues with the bottom face of Shapeways models.

Not quite - it was designed so that it would not physically fit into the build chamber in the orientation you describe (nose up so to speak). The reason that the back face is rougher than the rest of the model is the overhang of the cab roof. Since the roof needs to be supported by wax, the entire rear face of the cab is 'submerged' in wax so to speak. In summary, this model was printed exactly as I intended: "roof up."

[Dave Schneider]

No worries Alwyn. I didn't feel shot at. I agree with everything you have posted and share the concerns about fragility. I will make do with what I have and look forward to a better model in the future.

Best wishes, Dave

[daniel_leavitt2000]

Yeah, it's the artist fault.





Jason

Jason, is that one artist's project or is Shapeways combining several people's projects into one build?
If it is a single project, this just validates my point. Yes it is intracate and took a lot of effort, but does not take into consideration tha limits of FUD production. Its like designing a detailed tooling for injection molding that has undercuts: it may be more accurate, but it does not take into consideration the limits of injection molding.

If the designer made a flat model, these FM switchers would be killer. As is, they really can't be used.

As you pointed out, this requires us to be able to orient the model, which is not possible with shapeways. Maybe we should look elsewhere?

[wcfn100]

..or is Shapeways combining several people's projects into one build?

Bingo.  That's why it's so affordable. 

Jason

[mmyers05]

Bingo.  That's why it's so affordable. 

Jason

Has anyone ever actually encountered a FUD model that was printed from a 'stack' like shown?

For other materials it wouldn't make much (if any) quality difference but for FUD it would clearly be night and day. I've probably had +80 shells through my hands and I've never seen it (but there's a first time for everything I suppose)...

[DKS]

Once you start making 'flat' models (car sides as separate pieces etc.) you start running into major strength/warping issues extremely quickly.

Based on firsthand experience, I can verify that flat pieces can warp like mad. I changed one of my projects from a full 3D render to flat parts, and they were so badly warped that they were unusable. And even if I was able to un-warp them somehow, Shapeways did such a poor job of de-waxing them that the parts were ruined. (They use heat, and the melting points of the wax and the acrylic are too close together to work reliably.)

[Hornwrecker]

Is there enough space between the shell and split frame to CA some brass shimstock to reinforce the long flat surfaces? Also, is it possible to add more weight to the Baldwin chassis?

[daniel_leavitt2000]

Based on firsthand experience, I can verify that flat pieces can warp like mad. I changed one of my projects from a full 3D render to flat parts, and they were so badly warped that they were unusable. And even if I was able to un-warp them somehow, Shapeways did such a poor job of de-waxing them that the parts were ruined. (They use heat, and the melting points of the wax and the acrylic are too close together to work reliably.)

Is the reason the parts warped becasue of the heat applied? If so, then we only need to find an alternative to Shapeways.

The more I think about this, the more I see a need where we can get a model oriented contractor to shoot the prototypes, and then have them resin cast.

We are so close to something totally usable, it may just take a few extra steps.

[wcfn100]

We are so close to something totally usable, it may just take a few extra steps dollars.

Jason