Re: Shapeways report

Bob McCarthy


      Is the part suitable for creating a mold to produce multiple parts?  Please email me off site to discuss.


Bob McCarthy

From: Al and Patricia Westerfield <>
Sent: Tuesday, September 25, 2012 9:20 AM
Subject: Re: [STMFC] Shapeways report

Tom – Your reports got me enthused to see if I could prepare a CAD drawing for a stanchion I need. I saw that Shapeways could build a part from a material that would suit my needs at a reasonable cost. I downloaded SketchUP8 yesterday and watched the instructional videos. I was amazed at how similar the controls were to CorelDraw that I had been using for years. Within 30 seconds I had prepared an appropriate cylinder. It will take some time to complete the drawing but I feel secure that I’ll be able to finish it in appropriate fashion to upload to Shapeways. Thanks for getting me started! – Al Westerfield

From: pullmanboss
Sent: Friday, September 21, 2012 6:36 PM
Subject: [STMFC] Shapeways report

On September 8 I wrote:
I've submitted a part to Shapeways to be run in the Frosted Ultra Detail (FUD) material Kent mentions. It looks to be 3D Systems' multi jet process, which is similar to the PolyJet process I have access to. The part is a heavyweight Pullman bolster assembly, the design is visible here:

The part is very complex but doesn't have a lot of surface detail. The price is very competitive - I ordered two at $14.04 each plus $6.50 for shipping etc. We'll see how it goes.

The parts were finished and shipped on Wednesday 9/19, as advertised. I received them the next day (yesterday).

To reiterate, here's what the design looked like:

And here's the part:

Not bad at all. That photo shows the part cleaned and primed so you can see the surface. Here's a photo showing one part as received, and the other all cleaned and degreased:

The glossy substance is residual support material, and there was a good bit of it down in the cavities and corners. It's wax, but I didn't want to heat the part at that point so I tried a succession of ultrasonic cleaning steps. First was with water only, then water with a shot of Dawn dishwasher detergent, then Chameleon paint stripper, and finally 70% rubbing alcohol. Each worked to some degree, judging by the clouds of debris issuing from the part at each stage. At the end, the part was pretty clean and heavily frosted. The remaining debris down in the cavities in the center sill was easily removed with a dental pick. I'm not suggesting this as *the* cleaning sequence, or even *a* cleaning sequence. I just wanted to start with the least aggressive cleaner and work up from there. The frosted appearance may be due to etching of the acrylic part by the alcohol, or just the appearance of the material itself when fully cleaned. (It *is* "Frosted Ultra
Detail", after all.) I have one more to do but want to show it at work before I clean it.

These next two photos show the part after a light coat of gray primer:

Coverage within the cavities was incomplete, as anyone who has tried to spray into a small, blind cavity will understand. It did give an interesting optical illusion as shown here:

The vertical cavities look like they have tapered walls, but I can assure you the walls are straight to the very bottom!

OK, some specs. I measured the overall length, from the edge of the vestibule floor to the tip of the mounting tang, the length of the "center sill" portion of the bolster, and the overall width. Here are the dimensions, with the design dimension shown first:

Overall length: 2.128", 2.135"
Center sill length: 1.465", 1.470"
Overall width: 1.223", 1.223"

Width is dead on, some "creep" in the length. Still, not bad at all.

There was a bit of "cupping" of the vestibule end of the part across the width. (The right end as shown in the photos.) These were the portions of the part that were relatively weak, in that there were no big gussets leading from them. I got rid of the cupping by heating the part in a microwave (33 secs on high), which softened it enough to let me hold it against a flat surface until it cooled. That was after cleaning but before painting. It has stayed flat.

I had run this part on our PolyJet machine, albeit in its low resolution mode. The PolyJet vertical walls were really rough. The vertical walls on the Shapeways part were surprisingly smooth. Actually, astoundingly smooth is more like it, with very good definition of details on the vertical walls. The lips around the apertures in the side walls (the apertures go all the way through on the prototype, but that would be an impossible part to cast) are very well defined, whereas on the PolyJet part, if you didn't know they were supposed to be there, you wouldn't see them.

There is much less stairstepping on the "off-horizontal" surfaces than I expected, but there is some. There is also stairstepping evident on the non-orthogonal flat vertical surfaces of the tapered crossbearers, but not on flat vertical surfaces aligned with the X & Y axes of the design. Particularly impressive are the vertical walls of the cavities, and that little curved portion of the top of the bolster.

I think this particular process is perfect for models of foundry cast parts, like this bolster pan. Such parts are tough to scratch build, with their blended surfaces and coved corners. The surfaces of the FUD part have a slight granularity which adds to the casting effect.

The key to successful use of any tool or technique is not to ask for more than it's capable of giving. Really fine detail ("The Full Culotta") is beyond the capability of Shapeways' FUD process. On vertical walls, impressive as the ones on my part may be, it would be prudent to leave off all but the coarsest details and add them later. And the waxy residue issue no doubt comes from Shapeways' keeping costs under control by using "one size fits all" secondary processes. Don't expect Shapeways' staff to spend any time critiquing your design or offering suggestions for improvement - if it passes their up front screening process, that's what they'll make, even if there are design flaws that render your part unusable. They will suggest a process and material, but the ultimate choice is yours. Learning and applying 3D CAD tools is not for the impatient, but the rewards and satisfaction are great. Holding a part you designed in your hand is a real kick!

I can't wait to submit some more parts.

Standard disclaimers apply, not connected with Shapeways in any way. In fact, they're really a competitor!

Tom Madden

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