When designing the original printer, I placed an end stop at home position of the X and Y axis and an inductive probe at the Z-axis. This works well in concept, however I'd like to add extra limit switches to the bottom of the Z-travel to keep the machine from hitting the frame -- it's an issue we are currently experiencing. If we lower the Z-bed to remove a print and then re-home the machine, the default behavior is to lower the print bed and then to home X/Y before homing the machine. This is where we experience failures and where I would like to install a few z-min end stops, one for each lead screw.
With regards to your second question: we are using servos to drive all of our axes. The machine was designed with the understanding that we may change out extruders or controllers in the future. Clearpath servos were chosen for their ability to substitute for stepper drivers and for the extra overhead power available.
We use the built-in bed leveling in the firmware now with two servos. I'd like to add a third servo in our next design to allow for true bed leveling.
If we use the break-out board to drive our servos, how do we tap into the expansion connector? I suppose that was the intent of my original question -- how to use the break out board to drive servos, but to also wire up a few extra limit switches (in case we need more than 5?)
Thanks for the wonderful support forum!