Recommendations for keying pieces to glue into a larger whole

I am preparing for a project that will require multiple printed pieces to be glued into a larger final piece. Does anyone have recommendations regarding:

** Should I create male/female keys? Draft angles if so?
** Just glue flush pieces together?
** In your experience, what sort of line will I see if joined?


I think FL has a white paper on assembly of a model cut into parts (an r2d2 I think) that has lots of tips for this.

It somewhat depends on how thin the walls of the parts to be joined together are. My experience is that thin walls tend to warp a bit more. For some parts it’s possible to orient them such that they won’t warp (assuming they’re cured correctly). But in general with walls less than 4mm a little warping happens in many cases, enough so that glue alone is likely not strong enough to force two parts into alignment. So if the surfaces being glued are thin, having some kind of overlap, key/slot, snap fit, or fastener (either tapped holes or hole on one side and slot for holding a nut on the other) is probably a good idea. I’ve done each of these in different cases and they’re fine.

Since you’re gluing (I assume some kind of cyanoacrylate?) a key/slot arrangement may work well.

One thing to consider is (depending on the material) the dimensional accuracy of holes can vary by orientation. If you’re using a standard resin, they’re generally hard enough to hold shape. Durable and tough are more pliable and you might see, for example, a slot larger than design in the direction parallel to the wiper.

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Thanks… I will look for the white paper, and I appreciate the heads-up on orientation. More info welcome, and I will post with follow-up on what I learn and do…

And here is a link to the information on R2 referenced above:

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