I have been going a little crazy trying to make my machine behave in the z axis moves. It seemed to lose steps all the time, especially when trying to v-carve something. In carving a name sign, if I didn't re-zero the z axis after every letter, by the end of the carving the router bit would clear by 3/8 inch and think it was at z zero.
I went through all the mechanicals: changing couplings, better feed, screw and AB-nut, and it improved a little - but not enough.
Oh yes, my machine is plywood/MDF, kinda like a JGRO with 380 oz in stepper motors, Gecko 540, and Mach3.
The last changes made, I think (I am saying this with my fingers crossed) seem to have done the trick. I don't know if all of them are necessary, but at this point, I am not going to risk angering the CNC gods by changing anything. Here are the changes:
1. I took the router power cord out of the cable chain to get it away from the motor leads. I recently read about electrical noise issues caused by AC lines being too near signal lines. I also moved my surge suppressor/plug-in strip away from my control box.
2. I changed the Mach3 engine speed to 35000 Hz.
3. I increased the debounce interval and index interval to 300. My understanding is that this helps screen real signals from noise.
4. I switched to Sherline half-pulse mode. I have no idea what this does, but I read the suggestion somewhere here, and thought I would try it. Perhaps it gives longer signal pulses...but then why is it called a half-pulse mode?
Okay with all of that, the router is behaving very well. If it is still losing any steps, it is very few. Yes, I would feel more confident, if I had run a hundred trials, but I am happy for now.
Oh yes, there is one more change I am going to make. I have ordered some insulated 14 gauge wire which I will use as my router power cord, to try to reduce noise even further. If I get real brave I may try to put the router power cord back into the cable chain after that switch.
Maybe this info will be helpful to some other soul lost in the horror of losing steps.![]()