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Not so much an alternative to Shapeways as an alternative to Projet (FUD). I haven't heard of another way to remove the wax (although the results might be better if the technicians were a bit more patient). That said I've received a handful of slightly 'melted' models; I requested reprints and then repaired the originals using 'old fashioned' modelling techniques (brass wire and styrene sheet). That's not always an option of course, but when it works out you end up with a free car/locomotive out of the deal...
Bryan, what company do you use for prototyping parts?
The other way to achieve is to do what Bryan has done and insert brass overlays. The is the way Dick Billings got that wonderful effect on the PRR Round Roof Box Cars. The brass etch he did was paper thin. I do believe that some of the patterns for Kaslo shops were done by 3D prototyping that was polished.
This entire conversation is still missing one more point.As an example I'll use ESM's White Tower building (which is not done by Shapeways but the printing technique is similar). I don't have time to take example photos so I'll just describe it.It is true that bottom surfaces of parts which are supported by wax will have rough surface, but it is not only the bottoms. If any part of the object protrudes beyond the surface under it, the wax will have to be built up to support that part. For example if you have a flat vertical wall of a building but in certain areas there are window sills then the wax will need to be built up during printing to support the sills. That wax will also be in contact with the vertical wall surface and will cause the solid vertical wall to have a rough texture under each sill and smooth elsewhere. So there are more problem areas than just the bottoms of surfaces...
I was thinking about doing the brass overlay just last night, to model the Burlington's unique Pacific Railway Equipment-built Silver Pendulum coach. It has side curvature similar, but not as drastic, to the Amtrak Amfleet cars and using Shapeways to create a skeleton to support the curve of brass sides and provide the smooth roof and support for etched ends seemed a great solution. I'm hung up on how to secure the sides to the Shapeways material though; which adhesive would be enough to resist the tension created by the curvature and provide a tight seam along the horizontal edges to minimize the roof seam best.
All maybe I can help explain the overhang issue- as each layer is printed it is very thin, if there were nothing there to support it in its design intent state then it would just flop down the next layer would hve nothing to adhere to. So the machine builds a layer of wax (or rib in a fluid RP) there tio support it.Matthew, not criticizing, here, I applaud your work. It may have been better design the model without the hood or the roof, at least from the model side's perspective, and print it with the walls vertical. One could add some break out cross bracing to keep the model from warping in the bed. If there were any warp issues with the roof or hood, they woiuld be reset when the modeler glues them to the sides, like a cap.The pictured bed stack example is visually missing one thing- in fud there will be wax surrounding every one of those surfaces on each designer's parts, in a traditional lazer/fliud RP process, the PR software would add thin ribbed support structure all the way up thru each part until any horizontal surface is supported. These ribs are a B-itch to remove from the intended surface post printing, i've done it.I'm afraid that until someone comes out with an affordale machine like Finelines uses, say in the $2000-$3000 range, where the user can control the orientation of the designs in the vat, manage the depth of the build, and not have to worry about other peoples designs, over time the investment would pay itself off. it is still unclear to me how much post print cleanup that Finelines does or how clean the model is after it comes out of the machine.
Bestine (heptane) dissolves the wax. I'm tempted to ask one of the contractors to send a test part "untreated" to see if using Bestine to dissolve all of the wax is a viable option. That would solve the warping, but does nothing to alleviate the uneven finish on some of the surfaces.
I'm not sure, but I think what Mark uses might require the 3D model to be broken down into small pieces. Not saying it couldn't be done, but the drawings would probably need to be re-worked.Ever think of asking the designer to send the file to Finelines and get a quote for micro green. (I'm guessing over $200 tho)
If you use Bestine to clean the ProJet core, any super glue should do. I used the CA+ from Gorilla Glue, which supposedly has a little flex to it. But don't design it to be your final model. Design it to be a master from which to make polyurethane castings. The key is to have the master survive long enough to make molds from. With the urethane castings, you won't have to worry about the disparate materials separating over time, and you save a couple of the first-generation castings for future molds if so desired.You also should pre-curve the sides before laminating them to the core, in your example, which would reduce tension. That is what was done for the Keyser Valley caboose roof parts. I used a large X-Acto knife blade as a rolling pin on the etchings until the curvature matched that of the RP part and then cemented them in place.
What always holds me back is this: since I can't specify the orientation, I am always "playing the odds" so to speak. Consequently, it's very difficult to justify designing to a specific orientation only to have the model rendered in another (to end up with the problem that bbussey described earlier).
Excellent, Bryan! Thanks for the problem solving. I didn't even think about molding them. Not that it would be a hot seller, only three prototype cars were made; one each to the Burlington, Great Northern, and Santa Fe. I don't know of any existing photos of the latter two to know how they were painted.