This is kinda why I just use the soft limits for now. I rapid around 300 IPM on both my mill and the router. Since zero position on the mill is usually center table, the soft limits work fine there. It also has hard stops. The only switch other than Estop on the mill is the upper limit on Z. Standar push button switch, but when I am rapiding up, it almost over runs that switch. It is moving so fast. I have to pay attention. Momentum is the issue.
This is even more true on the router. Probably have near 150 pound gantry. When X is rapiding @ 300 IMP and I hit a limit, like a car, it takes more time to stop than instant halting. It would run way over a switch. I have been thinking about a double switch setup myself. One for the slow zone. Typical cheap switch like you mentioned. Then a more accurate home switch that it would search for in slow speed. Not as worried about Z on this one, but X and Y are what takes awhile to zero in at home.
I have a hole drilled at 1" in both X and Y on all my jigs. Right now though, it is still by eye.
This is fine if there isn't any problems and I leave the same jig on for a long period of time, but not near as accurate as the double nut ball screws. Trial and error then gets it dead on, but that costs a part or two sometimes.
I was considering using an index pulse card on each axis like
these.
Not real sure what the best way to accomplish this would be. Possibly having a long strip with a hole in it mounted to the axis. This metal strip would be long enough to be in this index pickup when the first switch is hit. Then it looks for the hole.
Only two card s would be needed I think. Home X and Y.
Thoughts?