loosing steps in z axis

[macatoms]

I have been loosing step in my z to the point of a crash that put a end mill into my table!It happens most on retract moves as it starts up I hear that grinding sound.After a second it kicks back in but does not reach its retract height.So when it goes back down for the next cut it adds the distance it lost on retract to the plunge.It sucks to run a part and keep 1 hand on the E STOP!I am new to this cnc game as this is my first conversion I dont know much about all the tech stuff with steppers and drive ect.I don't really want to know that much I just want my mill to work.I have a nema 34 906 in/oz kelig motor,a 8060 drive running at half step mode.My Mach3 settings are steps per 2400 velocity 38.124 accell 4.375 this is on a G704 with stock screws with 10TPI.I dont know if I have this set right.I want to thank Hoss for helping with some tips to this point.Any Ideas please let me know.My table thanks you!

[109jb]

What voltage are you running to your motor?
What amperage do you have going to it?
That is an 8-wire motor. Do you have it wires in series or parallel?

In parallel you should be at about 50 volts and 6 amps
In series you should be about 115 V and 3 amps.

If you are running a 10 TPI lead screw with the drivers set for 1/2 step then you should be 2000 steps per inch in your controller software.

Are your gibs too tight?

Lots of things to consider.

[hoss2006]

Is the z motor an 8 wire and if so are you sure it's connected bipolar parallel?
The stock screw is 6 tpi but your 2400 steps/per is correct for direct drive, are
you running a belt reduction?
Hoss

[macatoms]

I HAVE 48V AT 6 AMPS ON A 4 WIRE MOTOR WIRED BIPOLAR PARALLEL.MY BAD ON THE 10TPI IT IS 6 AS HOSS POINTED OUT.IT ONLY DOES IT PART TIME THE REST OF THE TIME IT SOUNDS AND RUNS GREAT AS FAR AS I CAN TELL.

[Connor9220]

I HAVE 48V AT 6 AMPS ON A 4 WIRE MOTOR WIRED BIPOLAR PARALLEL.MY BAD ON THE 10TPI IT IS 6 AS HOSS POINTED OUT.IT ONLY DOES IT PART TIME THE REST OF THE TIME IT SOUNDS AND RUNS GREAT AS FAR AS I CAN TELL.

It's possible that the jam nuts on the Z axis are too tight. Its also possible your shaft adapter tightens the jam nuts and loosens them causing issues. I didn't have my jam nuts tight enough and it unscrewed them causing the head to drop Anyway, What is the top IPM you can do with the Z? I'm running stock screws with a 570oz-in and can push 70IPM but have limited it to 50IPM. If you are not able to get those speeds then check that and maybe check to gibs to see if you have the to tight.

[Connor9220]

It's possible that the jam nuts on the Z axis are too tight. Its also possible your shaft adapter tightens the jam nuts and loosens them causing issues. I didn't have my jam nuts tight enough and it unscrewed them causing the head to drop Anyway, What is the top IPM you can do with the Z? I'm running stock screws with a 570oz-in and can push 70IPM but have limited it to 50IPM. If you are not able to get those speeds then check that and maybe check to gibs to see if you have the to tight.

Oh yea. SLOW acceleration helped allot.