If one of your stepper motors decides to stop moving and the others are moving during a CNC milling or laser cutting job, then there could be two things that could be causing this.
- The motor found its limiting torque (usually comes with a not-so-pleasant sound). This is where the control software is trying to move the stepper motor too fast (velocity, or too fast too quickly, acceleration) and the load against the stepper motor (inertia of the machine, or the material against the end mill while milling). Recommended action is to lower the velocity and/or acceleration, and/or lower the feedrate when cutting.
- There is a wiring issue with the wiring from the driver to the motor. This could be a loose wire, or a chafed wire (or two shorting together). It can also be a loose digital wire from the controller board to the driver. Sometimes wire ties can be the culprit. Recommended action would be to thoroughly inspect the wiring.
It's probably not the limit switches since that would cause a stop to the entire motion of the cnc router or laser machine.
Sometimes Mach3 will show a status when something goes wrong, but in cases where the motor is stopping due to its torque limit, then that would not be shown in the status. It's always good to check it anyway.
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I need to clarify my situation a little better after going to my shop and trying to run another program on Mach 3. About 15 minutes into the milling process all the motors (2-X axis, Y axis and Z axis)stop but the program continues to run. I stop the program and after a couple of minutes when I try to restart the program all the motors start working again. Then after another 15 minutes or so, all the motors stop again. I checked and rechecked my wiring. This has never happened to me before when running the same programs with the same setups and motor speeds. All of a sudden when I reloaded a program I successfully used before it does this. Do you have any recommendations?
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Yeah, it sounds like a more complex issue. Have you tried running in the air without using the spindle. This may be a power related issue.
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That's exactly what I did. I ran the program without the router motor on just to see if the motors would get through the whole program but they stopped working after about fifteen minutes and then I was able to start them again after about 3 or 4 minutes. I never had this problem before so you can imagine my frustration especially after ruining a couple of projects on expensive material.
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Sure. I can completely understand. Try this: disconnect all but one of the driver from power and digital connection and do the air run. Repeat this for each driver and note your findings. This will rule out the drivers causing a power failure.
Also, is your stepper motors and drivers on a separate power circuit from the computer?
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I will try disconnecting each driver and digital connection, which will be a real pain because it will be hard to access.
All the stepper motors, drivers and computer are plugged into the same power strip.
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Ok, so there is no power failure going on, but I believe it is necessary to test each stepper motor and driver pair individually. Hopefully that will lead to a conclusion.
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It will take a little time but I will do it and report back on my findings.
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Curious, what machine is exhibiting this problem?
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I purchased a BYCNC kit back in 2009 with an approximate cutting area of 2' X 4'. I later changed out the Z-Axis Motor and controller for a larger one and have two X-axis motors and controllers. In 2010 I rebuilt the machine out of birch plywood instead of the particle board that the kit supplied. I sent Patrick pictures to him. The machine never gave me a problem till now.
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Thanks for the update. This is Patrick by the way. I answer pretty much all of the Customer Service questions. That machine has given quite a good history.
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I love the machine and made a number of samples of my work for my e-commerce site, but I can't start selling product until I know this problem is solved because I will not be able to fulfill orders. I finally got all the electronics out of its enclosed protected area near the machine so that I test each controller as you recommended. I hope the problem can be rectified. Will let you know.
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Thanks.
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I tested each stepper motor and driver pair individually and they worked so what might be the next step?
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Did each stepper motor driver pair work for the full +15 minutes?
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Yes, I had them in operation for over 30 minutes.
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Ok, well it’s good that the motors and driver are ok. We are now down to the power supply and the breakout board as possible causes for the stop. I have a feeling it may be the power supply where with all three drivers drawing current and the power supply maybe getting too hot. Is the fan in the power supply working? You can also test to see if there is 36 volts on the power supply voltage output (V+ and V-).
Regarding the breakout board, if you have an oscilloscope, you can test if the driver pulses are outputting, but I would consider this as a last resort after you determine if there is a problem with the power supply.
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I tested the power supply with a voltmeter and each output was registering 39-40 volts. I think the problem may be the g-code. I am using V-Carve pro to do design and output to Mach 3 Mill g-code. When I studied the g-code lines I noticed that further into the program the z-axis g-code stopped zeroing out to move to the next part of the carving. In other words both the x and y keep moving and the z just stopped working because there was g-code missing. I think something is missing when the design was converted to g-code. I noticed that when I ran a simpler project it worked without problems so I need to investigate this further.
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New Update, Its not the g-code. I started to run the long program and everything was working fine until about 45 minutes into it, all the motors stopped working (but the program was still running) and there was a high pitched hum. When I put my hands on the motors they were all trying to move but it seemed they were all stalled. I turned the power off, gave it a minute and when I turned it back on I was able to move the motors again. Could this be a power supply problem?
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It does sound more and more like a power supply problem. Did you test the power supply after the motors stopped?
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No, I did not. What should I be looking for.
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It’s good that you know the voltage during normal operation, so you have a base understood. If the power supply is the problem, the voltage will be reduced or non existent when measured after the problem.
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Also, check to see if the fan is running on the power supply when the motors stop. That may (not absolutely) be an indication.
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I'll run another test, check the voltage and fan when the problem occurs and let you know. Thanks for hanging in there with me as we try to resolve the problem.
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It’s my pleasure. This service is rarely used and is faster then email. Odd nobody uses it. Any recommendations you can give would be great. No problem using this FAQ to pose ideas as this resolution will be cleaned up later.
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It might be that people do not realize you can communicate through the sight like this because they are so used to e-mail and texting. You may want to explain this feature in the customer service section.
I ran the program this morning and it did not take long before the motors stopped. While operating the voltages for all three motors was 46 volts, when the motors stalled (and again there was a high pitch hum) the voltage went up to 60 volts and the fan on the power supply was operating.
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So, the driver work individually, but not all together. There is a high pitch sound when the motors fail. You have noted 60 volts from the power supply and the supply fan remains on. This is a difficult issue to resolve, but it seems to me that your power supply may be bad. The 60v measurement tells me that the current dropped and ohms law tells us that is current drops, volts will rise if the resistance stays the same.
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As one last test I am going to test each driver again and let them go through the entire program because it seems that the failure can occur at the beginning or towards the end of the program. When I originally tested ach driver I let them run for about a half an hour and the program takes over an hour to run completely. I just want to make sure that it is not the drivers. I will report back when I finished but as you noted it may be the power supply but I want to make sure.
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That’s a great idea.
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I just ran the x-axis through the whole program and there was no problem especially since I have two NEMA 23 motors moving that axis. Before I check the Y and Z could having a NEMA 34 on the Z axis with appropriate controller be a problem. I used the larger motor on the z axis because the router I am using is a large 1 1/2 hp. I've run this program in the past with this set-up and have not had a problem.
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Having a, say 3.0 amp driver, driving a stepper motor that typically requires a 6 amp driver would not seem to be an issue since the driver is limiting the current draw, but the driver may not be able to handle larger coil and back EMF with the protection on the 3.0 amp driver. With that said, I don’t believe that is the issue in this case.
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I don't either because I was able to run this and other complicated programs with this set-up in the past. I will let you know on the y and z axis.
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Thanks
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I ran the Y axis and z axis separately through the entire program and there was no stopping or problem. I guess the culprit is the power supply and I'll order a new one and hope that resolves the problem.
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Yes, that is the most probable cause. Please keep me informed. Thanks!
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Received and installed the new power supply. I ran the program with the router on and it worked flawlessly. The program runs for an hour and a half and I did not have a single problem. I guess it was the power supply but I was glad to go through all the diagnostics we discussed before replacing it. I hope this power supply lasts a lot longer than the last one. Thanks much for hanging in there with me and coming up with the solution.
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It’s my absolute pleasure and I am so happy to hear that the power supply replacement solved the problem.
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Y axis stop working X & Z work fine Y axis has two motors have check wiring & connections new breakout board still the same port & Pin set OK dont no were to go next David
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my cnc plasma cutter will run out the program when cutting. what is the cause?
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The cnc plasma question shod be a separate question. Can you pise that question by clicking the customer service live menu button at the top? Thanks.
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WHAT CAUSES ONE OF MY TWO AXIS MOTORS TO STOP WHILE THE MACH3 PROGRAM IS STILL RUNNING