Using a surface with kerf to split a shape.

scott_hess

As a challenge, I was trying to model an "impossible dovetail" box for a 3d printer.  A bit I'm a little stuck on is how to slice the box into two parts with consideration of tolerance.  As far as I can tell, the sketch I'm using to split the box is a zero-thickness surface.  Based on past experience, I know I'll need a something like .1mm on either side of the cut to make for a reasonable interlock.

The best I can figure right now would be to build a shape and use that to split things, which will be ... annoying.  Doable, but annoying.

Work in progress:
   https://cad.onshape.com/documents/d8640e8237336dfd1fceeefe

konstantin_shiriazdanov

you can thicken splitting surface first, and use boolean subtract option

konstantin_shiriazdanov

you can thicken splitting surface first, and use boolean subtract option

owen_sparks

Makers muse fan by any chance 

@konstantin_shiriazdanov has the way there.

Another approach is to split with the surface, then follow that with a Boolean of one of the parts away from the other with an offset, and keep tools selected. (I was surprised to find that parts don't have to overlap for Boolean to work...)

Cheers Owen S

scott_hess

Yes, saw that on Maker's Muse, but it was in the background and I wasn't really paying attention, then I thought "Hmm, how would you manage that?"  Initially I was trying to draw on the side of the shape, like one does, before I realized that wouldn't be feasible.

I did work up a surface manually "extruded" from the original line segments by using a good dose of parallel constraints and constructs with distance constraints, and it wasn't as bad as I thought it would be.

Konstantin's solution is even nicer, though, because there's less duplication.  It certainly is cleaner if I want to modify the surface (as Maker's Muse did :-).

I'm not entirely sure what you mean by the offset in your alternative technique.  The change needed isn't to shift the shape by an offset, the "slots" need to be slightly wider while the "pins" need to be slightly narrower.  Do you mean like shift and remove the intersection?