Z motor very hot

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This topic contains 25 replies, has 5 voices, and was last updated by  Dui, ni shuo de dui 5 months, 2 weeks ago.

Viewing 26 posts - 1 through 26 (of 26 total)
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  • #22999

    sempul
    Participant

    Is there anything that would cause the Z motor to get very hot? It is doing a fraction of the work of the X and Y but it gets very very hot. I cant figure out why. Everything is from you Vicious1 nothing changed on my end.

    #23001

    Ryan
    Keymaster

    Has it always been “hot”. Can you give an estimate of what “hot” is. Theyvare rated to i think 50c over ambient. But since we use pla best to keep them under 60c.

    #23004

    Kevin Lopez
    Participant

    My z gets warmer too for sure. My xy barely get warm, if at all. I think this is because of that thing about how steppers work, the way they deliver power in their phases. And apparently a moving stepper actually stays cooler. It also might have to do with only 1 stepper on z, which the xy have 2 set up so the current is limited. Or does the ramps send out twice the current for xy? Not sure

    #23095

    sempul
    Participant

    Hot to the point I can’t hold my hand on it tight for more than 3-5 seconds. Like very hot. I have a laser thermometer somewhere and will try to get an actual measurement. It’s just wierd and counterintuitive. I’m glad I’m not the only one though.

    #23146

    sempul
    Participant

    Not the motor that runs the extruder. The one that pulls the gantry up and down.

    #23173

    Ryan
    Keymaster

    What is the voltage of your z axis stepper driver?

    #23216

    sempul
    Participant

    How would I know that? As in how do I test and get that number for you? It all came straight from you so I never had to learn how to do any of that.

    #23217

    Ryan
    Keymaster

    Unplug all power sources and try swapping the y and z drivers see if that helps.

    To check you need a multimeter.

    #23306

    sempul
    Participant

    OK I swapped them. If anything its hotter. I have a multimeter where do you want me to test?

    #23308

    Ryan
    Keymaster

    From the power plug ground to the small silver pot on the drivers. 0.7V is what is should be close to.

    Are you sure it is hot enough to burn your hand? Normally the driver will shut down from thermal overload long before that point.

    #23325

    sempul
    Participant

    Its hot enough that I cant hold it tight for more than 3-5 seconds before I am forced to let it go. Trying to find the laser thermometer to get you an actual reading. The heat sink on that particular stepper gets way hotter than the other 3 also.

    #23331

    Kevin Lopez
    Participant

    If it helps at all, my xy steppers get to about 85f, and my z gets to 115f, running the stock vref. Check for binding in your z, and I found that putting some white lithium grease on the all thread made it a lot smoother.

    #23433

    sempul
    Participant

    Yep it reads .7

    there doesn’t seem to be any resistance in the movement and I have Lithium on it. Shouldn’t matter either way as there is very little movement while printing. its .2 mm per layer at 28 mm/s so shouldn’t be taxed at all.

    #23435

    sempul
    Participant

    Found my infrared thermometer. Z is at 128 degrees. X is 99 and Y is 100. Does that seem right?

    Fahrenheit btw

    #23436

    Ryan
    Keymaster

    I really am not sure, since works and the setting are correct. Physically swap the steppers, and see if the problem follows.

    Even though it isn’t moving the stepper stays powered up to hold it’s position.

    #23437

    Ryan
    Keymaster

    That is much hotter than mine but well within specs, they are rated for I believe 50C over ambient.

    You can turn the driver down as well that will cool it down. go down in .1 volt steps or less.

    #23496

    sempul
    Participant

    OK. I mean if its ok then its ok. Just seemed really extreme. I did the swap with the Y and it stayed the same. So not in the stepper. Guess thats just where it sits at. Thanks. Just had me worried.

    #23497

    Ryan
    Keymaster

    Just turn down the pot on the driver. If you have a meter it only takes a second. Now that we have squashed the software bug we should not be having z axis issues anymore anyway.

    #23505

    sempul
    Participant

    I’m not. After much much much learning and tuning i am getting great quality prints. The heat just concerned me as it was so much hotter that the X and Y which do way more work. Does turning it down to say .6 or so change any settings or values?

    #23508

    Ryan
    Keymaster

    No not at all. Turning it down should do nothing but cool it off a bit. too far and you will start to lose power but .5v or so I doubt would be a noticeable loss in power. Better than warping a mount from the heat.

    #23980

    sempul
    Participant

    Just an update:

    Brought it don to .6 and worked like a charm. Its pretty warm but not alarmingly warm. Once again thanks!!!

    #31146

    geodave
    Participant

    I know this post is a few months old, but when testing my MPCNC with the MKS SBASE board, I noticed the Z axis motor makes a slight noise after moving the X or Y axis motors. After only a few minutes of testing, the z axis motor is warm & the x & y are room temperature. I am guessing the Z motor needs to be running some to keep it engaged. Mine does not get warm enough to worry about after 20 minutes of running, but thought this might be part of the issue of the Z motor getting warmer than the X & Y.

    #35423

    sempul
    Participant

    I turned down the POT to the driver as Ryan suggested and it fixed it right up!

    #35424

    Kevin Lopez
    Participant

    That is totally normal. The steppers make a slightly annoying ring when they’re activated. Once you tell them to move they activate and try to keep that position. My z also gets warmer but it’s fine. I really wanna try out that new leadscrew though 🙂

    #35425

    sempul
    Participant

    new leadscrew?

    #35427

    Another method, which is the one I used, is to replace this motor by a bigger one. On my machine the motors are cold, but the drivers gets hot. But it is much easier to cool down the drivers since they all are in the same spot. So if this turns out to be an issue, just replace this motor by a bigger one (by bigger, I mean longer here, they are actually the same diameter).

    And yes, it is normal that the Z motor gets hotter. The reason is that you want the motor not to move at all, so the stepper driver sends it current to hold the position. This current is quite higher than the current you need to jump from a position to another, so the motor gets warmer.

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