Monday, September 08, 2025
Pantograph Axis Driver With Cranked Arms
Putting cranks into the arms of the Axis Driver has allowed me to put the anchor points and drive nut outside of the range of movement of the flexure. This means that I can put a drive screw vertically through the centre of one end of the mechanism without poking the screw into one of the arms.
I took the opportunity to fix a whole load of my broken maths assumptions, and the structure appears to be behaving when I try a variety of movement reduction ratios. It's also a bit more compact, and thus more stable.
As range of motion is now a bigger deal from a prototyping and fabrication perspective, I'm going for a 2:1 reduction ratio in this prototype. In theory that should still allow movement of less than a micron, which is plenty when the smallest feature I can make is around 10 microns. Not too dissimilar from what you get out of a conventional 3D printer.
Unfortunately I'm not near my printer for a few days, so this is going to have to remain theoretical for a bit. I'll upload to github when I get back and have tested it, unless anyone hassles me in the comments below :)
