[Dominic-ASP]

I just bought a Chinese 3040Z-DQ 230W Four Axis Ball Screw CNC and followed the instruction from the manual to configure the machine with Mach3.
I started testing the machine with simple X Y Z commands using Mach3and my keyboard and noticed some really rough noise and experienced motor blocking/skipping at random locations on the X and Y axis. I did not experience anything wrong in the Z axis. There is definitely something wrong with the machine and/or configuration and I'm trying to get your advice on how to fix this and if any of you ever experienced similar problems.

To get a better idea on what I'm referring to, please watch my video and notice the problems encountered at 0:03, 0:11, 0:19.


Thanks for your help

[Abanks]

Sorry that you're having issues with your CNC. I wish I could help you out, but, I am having the exact same issues. I have tried different settings on the speeds and acceleration, but none of that seemed to help. Been looking on these forums for quite awhile and this is the first message posted that is related to my problem. If you figure out how to resolve these issues, please let me know. I will do the same. Thanks.

[Dominic-ASP]

I did greatly reduced the blocking/skipping by reducing my X and Y speed to 600mm/min in Mach3. At 800mm/min, it is as bad as it is in the video. Considering the fact that the manual recommends a speed of 2500 mm/min, I think slowing down the speed just masks the real problem which appears to be mechanical binding according to answers I have received in another forum. Even at 600mm/min, I still get 1-2 minor skip for every X and Y passes and this will most definitely affect the precision of the machine, which is bad.

Some of insightful answers I have received so far:

I'd suspect shipping/transportation may have caused it to get out of square/bent,etc...
Slowing max speed down will really just mask the problem.
I'd disconnect the ballscrews and make sure all the carriages/linear guides move freely.. Adjust as needed.
Also do your stepper drivers have adjustable/settable output current?
Could just need more current to the steppers but again that will really just mask the problem too.

[Abanks]

I don't believe my machine is out of square/bent. Today, I put a volt meter on the power supply, even when it goes into the STALL (that's what I'm calling what it is doing) im getting a steady 23.5 volts. I don't believe it's the power supply. When it goes into the STALL; If I quickly turn the stepper motor by hand, it will straighten up. I've made a lot of adjustments over the last few months in the "acceleration" & "velocity" settings, to no avail. It seems my machine runs better with a step-pulse or Dir pulse change. In conclusion, I'm leaning towards a computer pulse problem; Even though the driver test says "system excellent". If you have any suggestions please let me know. ((Check out the video)).

[kreutz]

Your steppers are stalling. If your stepper drives have phase current adjustment, please, check the set current is the right for your steppers, otherwise adjust it to the right values. Check also the PC for step pulse frequency stability, check adjusted maximum velocity and acceleration in Mach3. A 24 volts power supply will limit your step rate depending on stepper characteristics, nominally phase inductance and BEMF. Check motor mountings, couplings, mounting and movement transmission parts for rigidity, backlash, and mechanical binding by moving it from end to end, on each affected axis, by hand and manually turning the leadscrews back and forth.

[Abanks]

Not sure if my steppers have phase current adjustments. I believe my stepper motors are two phase 57/3.0A. Is this an adjustment on the stepper itself, on the driver, or in Mach3? You said to check the "step pulse frequency stability", is this done by runnIng a driver test? If so, my computer says "system excellent". The 24 volt power supply is what came with the CNC machine.
QUESTIONS:
1) phase current adjustment ( stepper motor itself, stepper driver, or Mach3)? There are some dip switches on the top of the drivers
2) check PC for step pulse frequency stability ( is that the driver test)?
3) what is "phase inductance" and "BEMF"?
Here's a picture of the control box
Thanks in advance. Attachment 271042

[kreutz]

Phase current adjustment should be on the drives. As the manufacturer for instructions.
Phase inductance is the inductance of the phase coils inside the stepper motor. Inductance acts as a resistance to changes in current in the coil.
BEMF is Back Electromotive Force, it is responsible for the coil current decreasing with increased rpms, it pushes against the current which induces it.

Coil current is what creates motor torque, so that is why torque depends on RPMs and coil inductance determines the power supply voltage necessary to make the motor move at higher speeds.

I am not trying to blame all your problems on the power supply, drives and steppers , so first check all the mechanical parts involved in the X and Y axes after making sure the drive current is the right for your motors. Then start by changing micro-step modes (on the drives and then on Mach3 the steps/in) and testing at different combination of speed and acceleration setting in Mach3. Make sure nothing else is running on your PC except for Mach3 (no antivirus, no network connection, no music playing, etc.).

Check also the parallel port and cable, as well as the individual motors' wiring.

Note: see also the following video: https://www.youtube.com/watch?v=ltnfI5XqtSo

[Abanks]

Not sure what kind of computer you are using but I tried an older dell dimension 4700'w/ windows xp and fixed the problem.hope this helps
https://m.youtube.com/watch?v=2OYVeW6YKfs

[kreutz]

............ You said to check the "step pulse frequency stability", is this done by runnIng a driver test? If so, my computer says "system excellent". ..............
.Attachment 271042

So much for the test software, the "excellent computer" turned out to be the problem

Congratulations!! and thank you for the follow-up. From now on I won't trust that software.