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Post by jbconn on Aug 22, 2014 21:52:46 GMT -5
Evening all.
I've been spending the muggy summer upstairs In the air conditioning doing some computer-aided design for a couple of 3D printing projects. One is a coach, so I'll be needing a bunch of windows.
When I finally got around to checking, I see that there seem to be few choices for printing clear or tinted window material. Shapeways offers nothing like it that I can see. Ponoko offers clear and tinted plastic that can be laser cut, but I was looking to have windows printed that had a shoulder to glue inside the car with the outside flush, to that may not work. Kraftwurx offers several water-clear material that may be suitable.
Does anyone have any feedback on these print services? Can anyone recommend alternative printing services?
Thanks
Jim Connolly
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Post by sbhunterca on Aug 23, 2014 6:25:43 GMT -5
I definitely wouldn't incorporate the glazing in the part- unless the part is oriented perfectly flat in the machine, the "glass" will suffer from surface texture, whether a pronounced stepping or a "striated" effect where the surface lies between two layers in the curing process. Make the frames thin enough- ensuring you stay above the minimum feature dimensions for the desired process and material, and use clear plastic or real glass for the glazing. The minimum dimensions may or may not work for you- you'll need to use a expensive material but these would be small parts, hopefully stacked closely on a sprue to minimize the volume taken up in the machine. Laser cutting may well be the best answer, using a laminated approach to building the step. My model of the Prince Edward Island Railway/ Canadian National Railways station at Georgetown, PEI uses both laser cutting and rapid prototyping... SLS printing (Shapeways WSF- the only reasonably cost effective choice for such a big part) for the complex roof sub-structure, with windows and doors laminated from laser-cut .020" acrylic parts. The walls, shingles, barge board, etc. were built using conventional methods: public.fotki.com/sbhunterca/georgetown-pei-models/Steve Hunter
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Post by sbhunterca on Aug 23, 2014 6:33:38 GMT -5
BTW, if you need tinted glass, try Tamiya's translucent paints. I used a mix of yellow and orange for the amber- coloured leaded glass transoms on the Georgetown station. The lead pattern was a CAD drawing printed on projection sheets, and I painted the rear surface to avoid damaging the ink.
Steve Hunter
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Post by chrismears on Aug 23, 2014 10:18:00 GMT -5
I'll echo Steve's thoughts on printing windows. Shapeways will print Frosted Ultra Detail down to a 0.020" thick free-standing wall. It should be possible to open up the back of the window a little large so that plain clear plastic sheet could be used to glaze the windows. It would also cost a lot less to since the printed parts are priced by volume.
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Post by jbconn on Aug 23, 2014 11:51:07 GMT -5
Thanks for your suggestions. The coach walls are 0.04" thick at the windows in the current design. I could thin them there to match the thickness of the laser cut material and insert the windows from the outside glued with microscale crystal clear to a transparent backing.
Thoughts?
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Post by sbhunterca on Aug 23, 2014 12:25:24 GMT -5
Hi, Jim: You didn't mention what type of coach you're building. I'm guessing it's one with sealed windows, like the Adlake frames. Yes, you could definitely recess the glass from inside to keep it at the right distance from the car side. 3D printed window frames could then be pre-painted and installed from outside, possibly using Canopy cement. Fit-up tolerance of the frames would be critical, so possibly a very tiny interference should be planned, and either the frames or openings could be lightly sanded to perfect the fit. If it's a heavyweight steel car or a wooden coach, wooden window frames could be made by laser cutting,and they too could just slide into openings from outside. That would achieve results similar to my mostly- scratchbuilt CNR combine #7377: public.fotki.com/sbhunterca/rolling-stock-models/4.html#mediaHope this will help a bit. Steve
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Post by jbconn on Aug 23, 2014 19:11:53 GMT -5
Sorry for the oversight. It is a modern bilevel commuter coach with sealed windows that are essentially flush with the car sides.
Jim Connolly
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Post by sbhunterca on Aug 24, 2014 6:23:32 GMT -5
Ahhhh, OK. Something like that might best be modelled with precisely- fitted laser cut acrylic windows that essentially press into the car sides. Again, the fit of each pane might need some light tweaking.
A clear panel of acrylic could be added behind them (maybe even with the blinds painted on it, if fitted to the prototype. This panel would give a positive stop to ensure all the windows would sit at an even depth in the car sides as they are inserted from outside.
Your favourite clear adhesive- Canopy Cement, Crystal Clear, etc could be used very sparingly around the very edges of the pane.
If the car has rubber gaskets, they could be built right into the shell and coloured with a paint marker, Sharpie pen, etc before inserting the glazing.
Good luck with this- it'll be pretty finicky work, but should yield great results!
Steve
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