Desktop size steel welded router 3 axis

[Tom J]

Tom - are you using proximity switches by any chance? I had very similar problems with my own machine - homing was very problematic. I had configured it to home Z then X+Y together. Z homed OK, but I had random limit switch trips while X and Y were moving. Turned out to be because the proximity switches I was using had no hysteresis. What should happen is that switch-on and switch-off points should be slightly separate. Mach3 homes the axis until it trips the switch, axis comes to a halt but slightly overshoots, then backs off slowly until the switch trips off. Machine is now at home position and the switch goes from home switch mode to limit switch mode in Mach3. However, because on/off points are so close, any vibration after that point can cause the switch to trip on again, which is where the limit switch error occurs and everything stops. In my case, the only problem switch was on Z, and might have been something like resonance in the mounting plate for the switch. Perfectly strong enough for its function where there is no physical contact but it's just a flat bit of steel plate edge-welded to the gantry tube, and we are only talking maybe 10um to trip the switch so not much movement needed.

Thanks Neale
I use inductive sensors with two targets.
My machine is quite stiff so there is no play or vibration.
I use good quality sensors for X,Z and cheap for Z because is easy to replace.
Switching signals are not erratic, just on off, not like in some cheap mechanical switches where de-bounce have to be used.
As I said problem is with XHC module while homing. Sometimes with external reset - input is received but no action - baggy software.

I made that post in my thread to seek better plug in or software.
I want to sell this module and have peace of mind that will work for somebody better than is working for me now.

[Neale]

Ah, you mentioned an IP/M, and it sounded as if you were having the same problems with that. A friend of mine recently bought a Chinese router that uses the XHC controller. AFAIK, he is using the latest version of Mach3 with the XHC driver that came with the machine, and that is all working fine. I know that he homes each axis in turn, though. The only homing issue was discovering that one of the proximity switch targets was badly adjusted so the machine hit its end stop before the switch. That's when we discovered that the target was a broken tap screwed into a roughly drilled hole, but it did have a locknut! Quick tweak and all was fine.

If you are satisfied that your machine is solid and beyond reproach, that's good. Mine is all-welded steel but the mounting plate for the switches could be a source of vibration, and there is around 50um backlash in the ballnut/ballscrew assembly, as far as I can measure. That's enough to go between on and off and back again with my switches. I'm glad I went with the IP/M from the outset, although even that has its little firmware oddities, as it lets me work around the issues.