Re: Consumer-grade 3D printers hit the mainstream


Robert kirkham
 

So far I have made reefer doors, fowler boxcar floors/underframes and a CPR reefer model in HO scale using Sketchup drawings and the Shapeways printing service.

My efforts are those of an amateur but, FWIW, in my opinion the fowler boxcar underframe is usable, but only because it will be under the car and mostly in the dark. I designed it without flanges on the bolsters or frame components - those will be added with styrene strip, That approach was taken as the material Shapeways offered would not produce a thin edged flange. From what I have read about the new material, it sounds like it would work.

The other parts I've had printed are not useable without a lot of additional work. I see a few problems:
- V groove siding on reefers: I was dumb enough to try scale lumber dimensions - it produced grooves so subtle they are less obvious than the grain of the material made while the part is printed. The problem arises as much from the printing process as from my use of fine dimensions - groove tend to fill up with material unless the gap is wider. On my second try, I enlarged the grooves about 50% That effort made little practical difference. Another 50% or 100% increase would be a better bet, and I will be giving it a try in due course.
- surface texture - is either grainy or granular depending on the materials I've used (white detail and strong flexible). I am looking forward to testing the ultra detail frosted stuff when $$$ allow another experiment. For now, to make the reefer acceptable I would have to scribe the grooves deeper and sand the board faces smoother - not something I relish.
- stair stepping on the sloped roof panels - requires sanding.
- minimum wall thickness - was .7mm, which is tolerable for a lot of things we do in HO but course for some. The new frosted detailed materials will work with a considerably thinner cross section. Again, I need to experiment.
- fit - I created small index features at the corners of the car sides. As a result, the parts fit together in perfect alignment. That is my favourite part of the process so far.
- floor/fishbelly underframe: I guess the floor was not made thick enough, as the whole part came out with a curve, bowing up in the centre, and down toward the car ends. It is flexible enough to straighten, and so I suppose could be made to work. But if making the part a half millimeter thicker will make it more straight and stiff, it will be worth the extra dollars.

The reefer - 2 sides, so ends, roof, floor/underframe - cost about $85 to print and have delivered. Not a good price for a lot of models, but if I was pleased with it, it would serve as a ready and replaceable basis for resin copies.

Someone mentioned using them for doors and ends or other parts. I am currently working on a Murphy-style inverted corrugation end for a CPR composite automobile and will see how that works. Like so many things, the drawing is as much a challenge for an amateur as anything else. For example, I seem to be unable to get Google Sketchup to render an HO scale rivet head. My thinking is to add them after the fact with Archer rivets, but that is going to get old in time. Another example - just how precisely to model the corrugations - what will show up in the printed version, and what will be lost. At this point, I'm using a fairly simplified profile as Google Sketchup seems to have problems with the very small faces that would be required with compound HO curves.

Rob Kirkham

Hoping this technology is improved and tweaked to meet our needs.

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From: "John Kellett" <soccrdad525@...>
Sent: Friday, May 13, 2011 11:22 AM
To: <STMFC@...>
Subject: Re: [STMFC] Consumer-grade 3D printers hit the mainstream

Hi Mike,

Yes design your own 3-D models, upload, then they verify, and you can have them
printed. Shapeways does have instructions for the process to guard against
'open' models. Key word 'open' meaning that edges do not align to form a solid
model.

The pricing that you see includes the shipping cost. Shapeways minimum order is
$25.00 from any of the listed products. And from order, production, to delivery
is usually 10 to 14 days.

The one shop I have ordered from is 'Stonysmith'. Stony's models are mostly Z
scale, but with some recalculations you can see that they can be re-scaled. Oh,
and all shop owners can set their own margin for their models.

John Kellett




________________________________
From: Mike Aufderheide <mononinmonon@...>
To: "STMFC@..." <STMFC@...>
Sent: Fri, May 13, 2011 2:09:10 PM
Subject: Re: [STMFC] Consumer-grade 3D printers hit the mainstream


John,

If I understand the site correctly, one can send 3-D models to them and have
them made! Wow! A game changer? Where's my Sketch-up!

Regards,

Mike Aufderheide

From: John Kellett <soccrdad525@...>
To: STMFC@...
Sent: Friday, May 13, 2011 12:47 PM
Subject: Re: [STMFC] Consumer-grade 3D printers hit the mainstream


Here is a link to Shapeways. http://www.shapeways.com/

To see what is in the model train arena, use the menu on the left side of the
screen. Mouse over "Hobby" to gain access to the "Model Train" category. I am
sure you will be surprised at the detailed work. Shapeways is now experimenting

with a new material "Frosted Ultra Detail" (FUD). If you watch the rotating
header, there is a bulldozer and a MOW truck, both are Z scale (1:220). With
the new FUD material, Z scale can be designed now down to the three foot
details. Shapeways has other materials including metal, and now ceramics.

One more item, these prices are not that bad.

John Kellett

________________________________
From: Tim O'Connor <timboconnor@...>
To: stmfc@...
Sent: Fri, May 13, 2011 1:22:36 PM
Subject: [STMFC] Consumer-grade 3D printers hit the mainstream


http://www.nytimes.com/2011/05/14/arts/design/makerbot-is-a-new-3-d-printer.html









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