Sunday, August 24, 2025
Parallel Pantograph Flexure Take Two
Had a few thoughts while away (the second half of my travels have been postponed), so here's the next iteration of the parallelogram/pantograph flexure. No droopy bits on the print this time. I chickened out from moving the drive platform more than +/-7.5mm because I want to do a few other tests before I stress-test it. But that's plenty for the next major version of the Maus RepRapMicron.
The flexures are now only 4mm wide instead of 6, and 0.6mm thick (2.5mm long BTW). Their profile has changed too, with the footings that hold the flexures being plain vertical sides, and the top flexures that have to anchor to a 45 degree beam now have dead flat undersides. Oh, and the top beam is now level with the bottoms of the upper flexures so no crud falls out during printing.
With the narrower, cleaner flexures this is far easier to flex and the torsion on the ends is vastly reduced. I'll have to put it in some kind of test frame and give it a go.
My main concern is that if I have a horizontal drive screw the thing is going to bounce up and down because the drive screws seem to always have a little bit of eccentricity - which matters when you're using microns. So the axis being driven will have to have good constraint in (what in this illustration is) the up/down direction. If not, I'll just have to build some complementary flexures into the drive frame, but I'd rather not have to.
This flexure system should work in 2 dimensions, but that's not what I'm designing it for. Letting it flop around on two screw-driven axes unconstrained at this point is going to introduce a lot of errors. Later, maybe.
