Feedback on possible 3D-printed scale parts

For several months I have been considering designing some 3D scale model parts that could be ordered directly from Shapeways.com by the end user.

Just as a realistic test, I put together a basic ogive 3D nose cone that would fit a BT-50 and was messing around with uploading STL files to the Shapeways site, etc. At some point I want to order a nose or two in order to check out the final results. But I would like some feedback as to the sort of chute/shock cord attachments that should be included in the design. Some things to consider:

-Shapeways can 3D-print materials of varying strength, surface quality, and cost (so cord attachment design would need to be fairly robust)
-Shock cord attachments may add additional material to the model and raise cost (product cost is based directly on volume of material used).

I'm concerned about traditional attachment methods for those reasons. With that said, see the attached JPG for two possible ideas for a robust cord/chute attachment. The design reduces the worry about product strength by including two 1/8" holes that can accommodate a hardwood dowel (or aluminum tube) that can be glued in place as an anchor. I'm kind of leaning toward the flat bottom design at the right (less material), but the lefthand tapered design could be used even without a dowel.

I'm open to suggestions on shock cord mounting, if anyone wants to add their two cents. I was also considering a criss-cross mount centered on the end hole (Centuri-style), but I think it may be difficult to make strong enough (and also leave room for nose weight).

BTW, I am not planning on offering the nose style you see; it would be not worth buying when so many other similar cheap noses are available. Maybe if someone needed an exact scale nose or something it would be worth it.

I think it would be great for scale parts depending on cost. The thought had interned my mind while taking some CAD classes. There was a proto typing machine in one of the labs at the college. I watched it work one day and it looked cool.

I'd say buy something from the material you're choosing to use and then try just epoxying a length of kevlar cord to the inside. If the epoxy grabs well, you're done and with a very simple method. I use that on homemade cones all the time.

Sandy.

My Saturn V transition wrap replacement

Scroll up to see CN Tower parts from Shapeways.

What would have been the cost of those nosecones if they were FDM'd? I have seen some fully FDM one-piece rockets that look really cool, but I'm not sure how expensive they'd be.

rocketroar.com said:

What would have been the cost of those nosecones if they were FDM'd? I have seen some fully FDM one-piece rockets that look really cool, but I'm not sure how expensive they'd be.

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Shapeways has a $25 order minimum. The Saturn transition is 0.03" thick and cost $22 & change. It has a 4" base diameter and is 2.3" tall.

The White Strong & Flexible material has a base price of $1.50/cm^3 (the bigger you get, the cheaper it gets)

Thanks for all the feedback so far...

Phil Ash, what is your impression on the White Strong & Flexible material so far? I am wondering about the paintability of it since it is a type of nylon; however, the Shapeways folks did some (brush) painting trials and seemed to have decent results with using acrylic paints (they tried Tamiya).

I'll probably do my two initial trials using WS&F and one of the other plastics (like the white detail or something).

Thanks...

Meatball 1 said:

Thanks for all the feedback so far...

Phil Ash, what is your impression on the White Strong & Flexible material so far? I am wondering about the paintability of it since it is a type of nylon; however, the Shapeways folks did some (brush) painting trials and seemed to have decent results with using acrylic paints (they tried Tamiya).

I'll probably do my two initial trials using WS&F and one of the other plastics (like the white detail or something).

Thanks...

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I've only just put a layer of Rustoleum Primer on the CN Tower Antenna but it's taking it well. If you're likely to make the next SEVRA launch, I'll bring it along.

PhlAsh said:

I've only just put a layer of Rustoleum Primer on the CN Tower Antenna but it's taking it well. If you're likely to make the next SEVRA launch, I'll bring it along.

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I'll have to get back to you on that--it will depend on the weather. I know Jess doesn't want to stand outside for an extended period of time in the heat wave we've been having, so we'll have to play it by ear. But I appreciate the offer to bring it, nonetheless. Thanks.

Meatball 1 said:

I'll have to get back to you on that--it will depend on the weather. I know Jess doesn't want to stand outside for an extended period of time in the heat wave we've been having, so we'll have to play it by ear. But I appreciate the offer to bring it, nonetheless. Thanks.

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I'll post pictures here as it progresses.

Hey, Phil... Here are a couple of questions for you regarding your Shapeways models:

1. With your CN Tower model, how did you deal with the orientation of it--did they print it pointing skyward or on its side? (in other words, should I position my nose cone geometry vertically or not?)

2. They seem to have an odd design rule for wall thickness of WS&F objects longer than 117mm (4.6 in). What sort of wall thickness did you use on the tower?

3. How sturdy feeling is your Saturn transition at .03" wall thickness?

Thanks...