RepRap: Blog

I tried to get a bit more range of motion out of the Axis Driver so I could quantify the rotation of the XY Table. In the V0.03 Axis Driver the Pivot Arm bottoms out on the limit switch before it hits the end of travel. So some low-hanging fruit was just to lower the limit switch. Well, that didn't play out as well as I'd hoped. I managed to get it moving down an extra 1.5mm, which extends our range of probe motion to a whopping 3mm. Damn, I need 4.

Green Axis Driver with slightly greater range of movement on the left.

The problem is that the Probe Arm is on a simple pivot. As it swings up and down, the horizontal distance between the pivot and the drive nut decreases. Eventually this overwhelms the compliance of the frame and the drive nut seizes up.

FYI Here's the new Maus Axis Motor Assembly. I've changed the direction the switch wires lean in, and added a slope for the Pivot Arm to squash them against (which is what I intended to to in the first place.

To fix the binding up issue I need the all-new Axis Driver, and that's going to take a while to develop. Initial development won't take place installed on the frame, so development can happen in parallel.

The smart move is to reassemble the machine to V0.04 specs and make sure that still works. Once it does, I'll push the remaining changes into Github with the construction docs and get on with a few deposition/material experiments. Unless I find anything astounding out while rebuilding V0.04, the parallelogram-based Axis Driver will have to wait for V0.05, and that should have a better range of motion as the drive nut will be moving linearly.