I shielded all axis wires and ground the shielded wire.
After that i run machine but the issue of z axis was still as it is.
After that i replace the BOB and remove spindle cables x axis cable and the y axis cable from the BOB. And also from electricity. Just Run only the z axis. But the problem with the z axis is still the same. I also changed the z axis motor. The new motor has 2.8 torque. But the problem is that it is not going to be solved of z axis.
Also i added emi noise filter on my 220v too
Sometimes i thought why i am into cnc thing
Does this machine use a USB interface versus a parallel interface card? If this is a USB interface, my bet is you are getting EMI interference causing the z axis to move just slightly as you try to move. You might be able to resolve this by purchasing a USB isolator, which is cheap about $15 and it isolates the laptop from the machine, so no EMI can cause Mach3 to do strange things.
Russ
Chmfhm,
The fact you have a shielded USB cable with ferrite beads at both ends is great but this does not isolate the PC from the CNC electrically. I had the same crazy issues going on with my USB KFLOP board it worked but would do strange little moves and suddenly lose contact and re-establish it was making me tear my hair out. Someone on Cnczone metioned USB isolators and I was out of options so I ordered one which was under $15 and plugged this little board right before the PC and the USB cable plugged into the isolator. Just like magic my issues disappeared. I still use it today. This is an example of what they look like there are many makers of these units.
https://www.ebay.com/itm/18301419381...QAAOSwDEBcRWGU
Mactec54,
It is true noise could impact other axis as you suggest. On my machine I had strange stuff happening only on Z axis as the spindle moved around those cables got closer to EMI sources. This also could be the weight of spindle causing motor to slip due to weight it is being asked to support. A counterbalance shock might address the issue. A good test would be remove spindle and check and see if it keeps dropping
If there is EMI from the spindle, it's from incorrect wiring, he still had the problem without the spindle and other axes connected
I think he did remove the spindle.
If you watch the video, it moves all by itself after the machine has stopped, it's getting a signal to move from the control, this could be bad Optos as well, although he tried another Board and it still happened, it could be the stepper Drive also
Mactec54
I connect sheild with wite at motor end and that wire directly connects to ground cable.
As i told you i remove all axis wire and also remove spindle wires from Bob and from power supply. Just z axis wire connected to bob and powr supply.
First 57hs76 2804 motor is installed on z axis which has holding torque of 1.8nm now i install 57hs100 2804 motor which has holding torque 3nm.
The Shield connection is incorrect, it must be clamped at both ends as in the photos I posted, you can't use the drain wire connected to Ground, using the drain wire is ineffective and can cause even more problems that what you already have. look at the photos again this is the correct way to clamp the Shield.
Mactec54
I just removed the spindle from the frame. Then place a piece of mdf under the spindle holder and zero the z axis in mach3. Then i check the mdf piece by moving it back and forth under the spindle holder. Then irun the G code. After 5 minutes I stop G code to check again. I try to place same mdf piece under spindle holder but was not able to insert under spindle holder.
I sending you link of video you can check in start of video it is movable under spindle holder. And in last of video you can see clearly that I am unable to put back again mdf peice under the spindle holder.
https://drive.google.com/file/d/13YhOtTQylaEcSZHMkzS3089ZMaXFtdRl/view?usp=drivesdk
Also I swap x stepper drive with z to check whether it's a problem of stepper driver or not. But problem remain same
Very strange issue. Since you did not have the spindle running, I am going to venture a guess this is not EMI interference, however it can still happen from other sources. I am leaning towards some kind of mechanical issue, can you check your bearings on the Z axis and see if anything in loose. You also need to check backlash on the Z axis to see if that is playing a role. Did this machine every work correctly?