Best Of Pennsy Position-Light Signal Head - Shapeways Project?

[Ian MacMillan]

...Did I mention that Shapeways does not tell you how to do this, you have to search their forum? ...Don't ask me why the part turned white.  I don't have a clue. 

Here is 14+ pages of lovely reading for ya!
https://www.therailwire.net/forum/index.php?topic=28137

[peteski]

While it is not quite perfect, it sure is a big improvement over the first version.

[nscaleSPF2]

Thanks for all of your encouraging words, guys.  I really do appreciate it.

Jason, thanks for your suggestion, but I do not have the tools or the skills to produce a casting.  And since I will only need a few parts, a casting is not be justified.  You do make a good point, though.  The Shapeways parts are not cheap.  The ones made of FUD cost $5.17 each.

Ian, you have made my point about Shapeways.  Fifteen pages of speculation and conjecture about the best way to produce a model part, with little to no input from the Shapeways factory.  I reread the post just to see if I missed anything.  It's quite funny in parts, though.

The LEDs have been installed, and the signal is back in the paint shop.  More pictures to follow.

Jim

[Lemosteam]

nscaleSPF2,  you might want to try to have shapeways make the part with the main disc horizontal.  Layered RP works best if the cross-sectional curvature is in the plane of the layering.  Also I was thinking that if you hand drill or use a diamond grit bit from the back using the round hile in the back as a pilot, you might be able to thin the shades dramatically.

Agree with Jason that if you can get one perfect, cast it.

[nscaleSPF2]

Lemosteam, the parts were printed with the main disc horizontal.  However, the shades were pointing down, and I think that the part could be improved if the shades would point up.  This is conjecture on my part.  At any rate, I do plan to have a few more parts printed with this other orientation.

I tried to drill the shades out from the back, but they deformed sideways since they are not symmetrical and the material, being plastic, allowed them to deform.  Result was that the shades pointed skyward after drilling.

Jim Hale

[Lemosteam]

It would print better withe the shades up.  Sorry about the drilling.  I was hoping that would help.

Has anyone here etched a piece of thinwall brass tubing (single side only, obviously)?  Crazy idea, I imagine getting the mask on would be difficult...

[DKS]

Has anyone here etched a piece of thinwall brass tubing (single side only, obviously)?  Crazy idea, I imagine getting the mask on would be difficult...

I think this would be harder than just grinding the tubing to shape, which I've done. After a while, you can do one in a couple of minutes.

[American Archetype]

One way to get a good orientation from Shapeways is to do multiples signals in 1 file. That is, say 1 laying flat with shades up, one standing up with shades horizontal. That way, regardless of which way they print, you'll end up with at least one good copy. Increases cost, but normally gets you a good copy. Typically, I do 4 up when that's critical -- as described above and then a mirror image. With the mirror image, it usually get you 2 very good copies and 2 less-than-ideal copies.

[Lemosteam]

I think this would be harder than just grinding the tubing to shape, which I've done. After a while, you can do one in a couple of minutes.

Ahh but for us mere mortals (and I do not mean that derogatorily), grinding 8 repetatively for each of 50 signals would be a nightmare.  One could probably get 8 per a 2" long piece of tubing, if it's even possible.  Use tabs and place those into slots in the main disc with a second etched thin PCB for the SMD's and that would make for a very fine kit, But I inderstand where and why the OP is going in his direction.

[Denver Road Doug]

Well, I'm no SPF so I have no use for this particular part, but I have to say that doesn't look too bad to me.  I'm looking at it at LEAST in O-scale size on my display...I suspect that on a layout it would be very acceptable, and of course that's not considering that some refinement is likely possible.   If I could get standard D-type heads done in that manner, sign me up.  (there may actually be some out there, haven't checked)

Anyway, nice work...definitely another example of things to come with this technology.

[nscaleSPF2]

One way to get a good orientation from Shapeways is to do multiples signals in 1 file. That is, say 1 laying flat with shades up, one standing up with shades horizontal. That way, regardless of which way they print, you'll end up with at least one good copy. Increases cost, but normally gets you a good copy. Typically, I do 4 up when that's critical -- as described above and then a mirror image. With the mirror image, it usually get you 2 very good copies and 2 less-than-ideal copies.

Thank you very much, American.  I never would have thought of that.  Best idea I've heard all day.

Jim Hale

[nscaleSPF2]

Here is the above part, with LEDs installed.



From the back,



I glued the 0603 LEDs to the back using CA, then painted them with silver, then weathered black.  Apparently, the LEDs were not sealed very well, because a small amount of paint leaked onto the front of some of them.  At least there was no light leakage thru the signal head, so I can probably reduce the amount of paint for future samples.  This should help the appearance, a bit.

I ordered some mast and ladder kits from Ben at BeNscale.com, on which to attach the signals.

Here is the obligatory comparison photo.



Oh, yes, I also contacted Shapeways to try to get the parts printed upside-down:

"Dear Shapeways Team,
I plan to order additional samples of this part, but I think that it can be improved if it is printed top-side down (inverted). Is this possible? I would be willing to pay for a sample printed this way. Please let me know how I can do this. Regards, Jim Hale"

Here is their reply:

"Hey Jim,

Thanks for writing in. When it comes to orientation within the print tray, I want to be upfront about what we can do. In each print tray, we are faced with a great puzzle. We have to make the plethora of different and unique models fit with in the specific volume. Each model has a unique issue that requires our engineers to use their best judgement (based of a lot of experience) to print that model.

Therefore, we have to be upfront and simply say that we cannot guarantee any particular orientation for models. There are just too many variables. I can speak with our engineers and talk to them about specific orders but I cannot guarantee that they will be able to do any specific requests.

I hope that fully addresses your question. Thanks for your understanding."

I plan to invert the model and order more parts.  We'll see what happens.

Jim

[Dave V]

Most excellent.  I would pay cash for that.  Get the orientation right, make a ton of castings of it, and I'm in for a dozen.

[robert3985]

Although these won't work for my 1950's UP (which used D-type signal heads with big "blizzard hoods" and lower-quadrant semaphores), I have enjoyed this thread and watching the process you went through getting an acceptable part.

The only improvements I would suggest would be to "thin up" the cross sections and do your 3D model so that the "natural" way for these to be printed is in the proper orientation.

I have a local friend who is the largest supplier of Nn3 products now (using Shapeways) and he "tricks" Shapeway's subcontractors (who they call their "engineers") into printing his products in the proper orientation.  His suggestion was to draw your 3D model in the orientation you want it printed, and if you can print enough to fill Shapeways' printing envelope...which is a rectangle...make your 3D model so that it can only be printed in a single orientation.

Keep up the good work!

[unittrain]

I'll take some too!!