Having issues with Z-Axis (left) motor
Hey guys,
I finished building my printer this weekend and printed 3 successful prints beautifully. I printed the logo, two tea frogs, and a large 190mm Mei model from Overwatch. Over 36hrs of non stop printing and everything worked great. However, I am now running into an issue with the left Z-Axis motor not working.
What I tried:
1. Raised the little black cones up
2. Loosened the z-axis bolts to the frame
3. Double checked the connections on the board
4. Rotated the motor so the wires did not hit the frame as it seemed a bit tight. I know this fixed the issue for someone else but did not for me.
5. The connection wires does not look like they were squashed to the point they broke connection.
Any suggestions?
Thanks!
Re: Having issues with Z-Axis (left) motor
Welcome to the world of printing and problem solving! 😀
You have apparently already ruled out the most likely culprits.
I think I would check the cables (to the motor in question) for continuity next. I don't know how hard it is to open the motor, probably dead easy. But it might be very very difficult to put it back together again.
Maybe running the initial self test again could break something, or maybe not. I would keep my finger on the 'power off switch' while testing.
I think either you have a broken cable, or a broken motor. I have no idea about how Rambo works and if it could cause this isolated motor failure.
I would unplug the connector to the Rambo, and then insert some very small pin into the end of it. Then, pierce the cable where it ends at the motor (with a little probe designed for this sort of thing) and measure continuity with a DMM (Digital Multi Meter).
If both cables check out OK, then they could still have broken off inside the motor housing, but I suppose that is not very likely.
Good luck, Mik
Re: Having issues with Z-Axis (left) motor
Disconnect the motor plug from rambo board. The motor contains two sepRate coils. If you have a test Meyer. On the ohms scale you should get continuity between the first two wires in the plug. And continuity between the other two wires but there should not be continuity between the first pair and the second pair. You only need to resort to pins, if the initial test show a disconnect....
Regards joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
Re: Having issues with Z-Axis (left) motor
Disconnect the motor plug from rambo board. The motor contains two sepRate coils. If you have a test Meyer. On the ohms scale you should get continuity between the first two wires in the plug. And continuity between the other two wires but there should not be continuity between the first pair and the second pair. You only need to resort to pins, if the initial test show a disconnect....
Regards joan
That is a much better method than what I was suggesting. I assumed that the motors would have some diodes, resistors, IC's or whatever else inside their housing, but Joan's post sounds like they are just contain coils of wire. Probably correct, but I don't really know.
Does anyone have a link to a technical page about the motors used for the Prusa i3? That would help my understanding a lot.
Re: Having issues with Z-Axis (left) motor
These are stepper motors ( http://reprap.org/wiki/Stepper_motor ), more precisely Nema 17 ( http://reprap.org/wiki/NEMA_17_Stepper_motor ), which indicates (partly) their physical dimensions
Here you can find how they work : https://en.wikipedia.org/wiki/Stepper_motor
Re: Having issues with Z-Axis (left) motor
I am going to try them tonight after work. I am hoping it's just the wires and not the motor "cross fingers". The original instruction listed to make sure the wire from the motors is facing towards the frame but I think this is what caused the issue as the wires were pushed hard against the bolt. The motor did work again for about 10-15 minutes during calibration but quickly failed during a print.
I'm not sure what a test Meyer is and couldn't find it online. Is it similar multimeter? I have one of those laying around. Will report back if I find a solution. Thanks for the suggestions guys!
Re: Having issues with Z-Axis (left) motor
A test meyer is very similar to a test meter - the only significant difference is one is spelt wrong 😉
Re: Having issues with Z-Axis (left) motor
A test meyer is very similar to a test meter - the only significant difference is one is spelt wrong 😉
HAHAHAHAHAHA! I was googling for a "test meyer" and was like what is this damn device. I do have a test meter handy and will give it a test tonight. Hoping I don't need to splice any wires but it may be the case.
Re: Having issues with Z-Axis (left) motor
...
... The motor did work again for about 10-15 minutes during calibration but quickly failed during a print.
...
...
That certainly sounds like a broken cable, or a cable shorting against something.
Re: Having issues with Z-Axis (left) motor
These are stepper motors ( http://reprap.org/wiki/Stepper_motor ), more precisely Nema 17 ( http://reprap.org/wiki/NEMA_17_Stepper_motor ), which indicates (partly) their physical dimensions
Here you can find how they work : https://en.wikipedia.org/wiki/Stepper_motor
Thank you Joris!
Most interesting.
So printing on the high power setting will make it less likely that the motor cannot keep up with the input signals, because it turns with more force. And the silent mode setting will make it less likely that the hardware attached to the motor will be unable to follow, like when the filament is ground away rather than pushed by the extruder stepper.
Re: Having issues with Z-Axis (left) motor
Strangely I cn usually spell Dyslexic,
it's easy words like Meyer... that are hard...
perhaps I should have said AVO... If you're old enough...
🙂
joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
Re: Having issues with Z-Axis (left) motor
Disconnect the motor plug from rambo board. The motor contains two sepRate coils. If you have a test Meyer. On the ohms scale you should get continuity between the first two wires in the plug. And continuity between the other two wires but there should not be continuity between the first pair and the second pair. You only need to resort to pins, if the initial test show a disconnect....
Regards joan
Got brought out my dusty test meter. I checked both ohms and continuity and the connections are working fine. I am 100% sure it's the motor not working.
Few extra steps I did to ensure it was.
1. Tested the motor on different z-slot on the rambo board. They both work fine for the right z axis motor.
2. The left z axis motor was tested outside of the frame and all it does is vibrate! Could a connection issue be the cause of this of do I have a faulty motor?
I removed the left z-axis and had both plugged in. You can see the left one is getting a signal for sure.
Tested continuity and seems solid between the two
Right z-axis works perfectly fine
Any other suggestions? I am very sad 🙁 I just put this together and it was printing so well. I am thinking it is the wire still but do not want to cut and splice it to reconnect if it voids the part warranty. Is there another way to test the wire as it seems to work fine with the test meter.
Re: Having issues with Z-Axis (left) motor
The Z motors are wired in parallel on the RAMBo, so the output from that is definitely OK.
The "vibrating" motor is typical of one of the cable pairs being open circuit, but as you have tested that, it would appear that this is ruled out.
However, I presume that you checked the motor coil resistance (by measuring the resistance of each cable pair at the connector) so that would also rule out a faulty motor.
Therefore I am at a loss as to what the problem is and you should contact support.
Use the "Live Chat" on the shop page and give them a link to this forum thread. If necessary they will be able to send you a replacement motor.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Having issues with Z-Axis (left) motor
Obert, I still think you have a broken cable core.
Sometimes it makes contact, that's why the motor ran again for a while during the calibration.
You might have wiggled the cables just right when you measured for continuity with the DMM.
I would test it like this: Connect the questionable motor to the rambo and get someone elst to turn the rotary selector to spin the motor, while you gently bend the cables in various directions along it's entire length. If the motor starts spinning insted of vibrating, contact has been made. You will soon figure out where the cable break is by repeatedly bending the cables so that the motor starts to spin or to vibrate.
Re: Having issues with Z-Axis (left) motor
Obert, I still think you have a broken cable core.
Sometimes it makes contact, that's why the motor ran again for a while during the calibration.
You might have wiggled the cables just right when you measured for continuity with the DMM.
I would test it like this: Connect the questionable motor to the rambo and get someone elst to turn the rotary selector to spin the motor, while you gently bend the cables in various directions along it's entire length. If the motor starts spinning insted of vibrating, contact has been made. You will soon figure out where the cable break is by repeatedly bending the cables so that the motor starts to spin or to vibrate.
I believe this is the case too but did not want to attempt to splice the wires on the motor if it voids warranty on the part. Do you guys have any links where I can get a replacement motor in the US? Shipping to Czech for a replacement may cost more than just buying a new one.
Re: Having issues with Z-Axis (left) motor
Obert, I still think you have a broken cable core.
Sometimes it makes contact, that's why the motor ran again for a while during the calibration.
You might have wiggled the cables just right when you measured for continuity with the DMM.
I would test it like this: Connect the questionable motor to the rambo and get someone elst to turn the rotary selector to spin the motor, while you gently bend the cables in various directions along it's entire length. If the motor starts spinning insted of vibrating, contact has been made. You will soon figure out where the cable break is by repeatedly bending the cables so that the motor starts to spin or to vibrate.
I just had a chance to test it and you are correct. The motor fully runs when the wire was pulled but started to shake once we let it go. It's the wire connections for sure. I plan to splice the wires near the motor and re-do them again. I'm pretty sure it's right around that part as the wires were really squished. Do anyone know which wire gauge size it is?
Re: Having issues with Z-Axis (left) motor
Maximum motor current is about 1.5 Amps, but is limited to much less than that within firmware.
You should be able to find cable to meet that spec.
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Having issues with Z-Axis (left) motor
The pictures of NEMA 17 steppers look like it would be easy to take it apart and put it back together, probably much easier than splicing cables close to the motor housing. Just open it up and solder new cable/s to the motor, or t least a longer piece of cable, so that the splicing does not sit in just the spot where the initial damage occurred. It will be thicker than the wire and get in the way.
http://fritzing.org/projects/arduino-driver-a4988-stepper-motor-nema17
Re: Having issues with Z-Axis (left) motor
I spliced the cables near the motor and near the connector. Put in new wires at 18 awg and then I realized it was the molex connector pins! I realized a slight movement on the pins would make the motor to stop or vibrate. It's giving me a headache lol, or could just be the election results. Currently having xyz calibration issues. Says my front left is not reaching. I'll report back after a few more tweaks on the frame nuts. The motor seems to be running fine but a slight movement could be throwing off the calibration.
Update: Looks like the problem is resolved. The issue was a combination of the wire and the molex connector! A slight movement on the molex connector somehow threw the voltage off randomly. I fixed it by opening and making sure the pins were extremely tight. What a headache but it's printing great again!