β€Ί β€Ί

z axis seems gone crazy

MattMatt Posts: 134🌟 Super Member 🌟
Some minutes ago, the printer stopped at 3/4 work after having printed badly most of a model. The z-axis seems gone. Both the motors slip, chew and toil in moving up or down. Time to change 'em? Or it its something gone with the z steppers' driver?
Post edited by Matt on

Comments

  • Samuel PinchesSamuel Pinches Posts: 2,695Administrator
    The stock z-axis grease gets sticky over time. Wipe it all off with alcohol / isopropanol, and then regrease: https://jgaurorawiki.com/lubrication
  • MattMatt Posts: 134🌟 Super Member 🌟
    edited August 5
    Hi Sam. Here's a video (I think: maybe a tl smoother burned off with some power surge I got in these days?). I have sewing machine oil.: where to put the lubricating stuff? Not in the thread I guess.
    Post edited by Matt on
    1.mp4 2.9M
  • Samuel PinchesSamuel Pinches Posts: 2,695Administrator
    Hi Matt, please see my link for recommended lubricants. Sewing machine oil is too thin for Z axis. Yes, lubricant should go in the thread. Sewing machine oil will just run down and drop off. You need to clean off all the old lubricant first, which may require you to turn off power and manually turn the axis to raise and lower the z axis, in order to access all parts of the thread.
    Thanked by 2giantrobot2001 Matt
  • giantrobot2001giantrobot2001 Posts: 101🌟 Super Member 🌟
    FYI if you are in the U.S.: I bought the tube of PTFE Synthetic grease you will find in the wiki here. I found it online cheap, and waited for the shipping. Then I realized they sell it locally at Harbor Freight tools for about the same cost, same exact item.
  • giantrobot2001giantrobot2001 Posts: 101🌟 Super Member 🌟
    I have a couple AS5s I picked up used.... One of my printers has a z axis rod that starts jiggling bad when you move up fast manually.  It shakes and makes noise.  I can see it was been being lubed with someting that looks like non-synthetic grease.  I figure the gear might be wore out, but after reading your post Samuel, I'm gonna scrub that old crap off anywhere I find it. keep it from wearing out maybe
    Thanked by 1Samuel Pinches
  • MattMatt Posts: 134🌟 Super Member 🌟
    edited August 6
    Ok Sam, hope I will not have to substitute the steppers anyway (have you seen the video, I guess). I asked whether to lube the threaded rod or the smooth rod 'cause, searching for video clues for the chocked behaviour, I stumbled in posts of people saying that the former shouldn't be "never" greased... Perhaps they meant greased with oil-based stuff... So I have to go for a ptfe (btw, the same sources said that silicone shouldn't be good...). Btw, I had also graphite, but I restrained from applying, 'cause the same sources said it would be electrically active (perhaps in this they was right). So I asked to you before making any moves. Wondering how a dried lube's rod might cause all this, as much as making the steppers unable to raise the whole (perhaps now that the printhead is direct drive and got the extra weight of the stepper, they went fatiguing over and over, until they came exhaust). In any cases, I have to begin to choose some spare stepper from alibaba...
    And this to try for the printhead (looks slimmer, without being too slim like the one which burned out...)
    Are they good?
    @Giant, I'm in Italy, I may try to get it from Amazon.it.

    @Sam, the links from amazon.com cap to items out of stock. Here I found some greases lithium+ptfe: shold be they forcibly dry or could they be even liquid? Only-ptfe-based sprays are the ones which are just dry: I see that the ones which feature also lithium look to be liquid-greasy.

    What about one of these?

    or this? (looks expensive tho)

    or

    this is what I found on ebay

    Any suggestions for a product to degrease?

    Post edited by Matt on
  • Samuel PinchesSamuel Pinches Posts: 2,695Administrator
    Hi Matt, I really think your steppers should be fine, no need to replace them. You do not need to grease the smooth rod normally, but some grease on the lead screw is important. All of the options you showed are ok. Anything PTFE based should be fine. The stock grease is very very bad.

    Graphite is good for some applications, but not good for 3D printers.

    For degrease, use isopropyl alcohol, or ethanol.
    Thanked by 1Matt
  • MattMatt Posts: 134🌟 Super Member 🌟
    Ok, I was just wondering how they were jamming out of the blue in just 10 minutes of work, without having given any symptoms of malworking.
  • MattMatt Posts: 134🌟 Super Member 🌟
    I'm afraid the steppers are gone: the lube has arrived but didn't worked. They still toil in turning. Hope the spares will arrive asap.
  • Samuel PinchesSamuel Pinches Posts: 2,695Administrator
    edited August 12
    @Matt Ok, double check the plugs are firmly inserted into each motor. Also check there is no damage to the wiring for those motors. Steppers and stepper drivers either work or dont work -- they don't usually "half work" or stop after 10 minutes. There's no reason for the drivers to be overheating, unless you were running in some kind of full enclosure.
    Post edited by Samuel Pinches on
  • MattMatt Posts: 134🌟 Super Member 🌟
    edited August 29
    Ok. The new steppers arrived. They don't work. I dunno whether it is matter of specs. This is what I ordered
    Besides the shaft being longer (which I arranged rolling up the thread), they don't even move a bit. Perhaps they are broken by facility (they bear some marks of abrasions: I suspect them being "refurbished"...), or their voltage/amperage specs don't fit the machine's.
    Post edited by Matt on
  • MattMatt Posts: 134🌟 Super Member 🌟
    edited August 29
    But I don't see any stepper motor suggestion/replacement in the starter kit, besides one looking slimmer.
    Post edited by Matt on
  • MattMatt Posts: 134🌟 Super Member 🌟
    It is there somebody there?
  • MattMatt Posts: 134🌟 Super Member 🌟
    edited August 31
    I see now that the steppers I received are ok: I tested 'em with the led method, and the led sparkled. So perhaps they aren't of the right voltage/amperage, or something in the printer went wrong e.g about the mobo or the tl smoothers or the powersupply or whatever. So now I'm afraid also to buy 3 (one spare) from Banggood, due they are also in China and if the problem aren't the steppers, I'll find myself with 3 stepeprs paid but not solving the issue.
    Post edited by Matt on
  • Samuel PinchesSamuel Pinches Posts: 2,695Administrator
    Hi @Matt , I'm happy to give advice, but if you don't agree, then there's not much more I can do. I don't think this is a stepper motor problem. Let me try to get up to date:
    - Is the problem only with the z axis?
    - Have you removed the z-axis lead screws, cleaned them fully with isopropyl alcohol to remove all blue grease, and then regreased with PTFE based lubricant?
  • MattMatt Posts: 134🌟 Super Member 🌟
    edited August 31
    Hi Sam. The threaded shaft was already cleaned and greased, but didn't worked with steppers attached. Once removed, the steppers still run like clogged without any thread attached. The shaft of one of them is visibily harder to turn by hand than the other. I attached the steppers one by one to the x-axis wire and didn't worked.
    Now I ran the led test with them too, and the led didn't sparkled. Or, better, I placed the led into the first two socks pair and the last two socks pair of the cable (like I saw in a video which teached how to tst steppers with a led), and it didnt worked: but when I placed it in the 2d and 4th and in the first and 3d, it worked! So the issue is that these steppers aren't dead, or what?
    Though the new steppers don't work anyway: perhaps it is due to an inverted cables' position! That's also why I pasted to you the link to these new steppers, so you might see from their specs if they were fit for the printer (btw, the ones from Banggood didn't specified too much, in order to compare both sets). I bought them in advance for any eventuality, in order to avoid waiting, due they came from China: I wasn't aware that you pasted a link to Banggood for spare steppers, otherwise I'd bought these yours.

    Post edited by Matt on
  • Samuel PinchesSamuel Pinches Posts: 2,695Administrator
    edited August 31
    Hi @Matt , please be patient with me, I'm trying to help you troubleshoot systematically.
    - Is the problem only with the z axis motion?

    Post edited by Samuel Pinches on
  • MattMatt Posts: 134🌟 Super Member 🌟
    Hi Sam, I'm patient: if I seem you otherwise, I apologyze, it wasn't my intention. Yes, the problem is with the z-axis steppers.
  • Samuel PinchesSamuel Pinches Posts: 2,695Administrator
    Dear Matt, I am just suggesting to take more time to work out how to diagnose the cause of the problem using what you have, rather than pursuing a "doesn't work, I will replace it" approach.

    Ok, so if the other axis work correctly, then we can test the z axis motors one by one, by using the motherboard outputs intended for the other axis. e.g. If you swap the plugs for the Z and X axis motors, you can test the function of the Z motors and see if they work. Note: the z axis motors are wired in parallel -- it may be better to unplug one of the z motors and try each motor one by one. Another alternative is to swap the stepper drivers for the E and Z axis on the motherboard. If this resolved the issue, then it would suggest a fault with the current Z axis stepper drivers.

    It is possible that the Z axis stepper driver could benefit from current tuning, but if you haven't touched it to date, then that would seem like an unlikely cause to me.

    Does this approach make sense to you?
  • Laser8302Laser8302 Posts: 164Member, 🌟 Super Member 🌟
    The stepper motors are wired in a non-standard way from JGAurora.
    You have to swap pins at either the motor or board in order to get the motor to function properly.

    If you have a digital multimeter, check the resistance at the main board connector with the original motor plugged in. I forget the exact ohm reading you are looking for but pins 1 and 2 should be coil A and 3 and 4 are coil B. Try to change the pinout so that when you plug in the new motor the ohm readings match the existing motor.
  • MattMatt Posts: 134🌟 Super Member 🌟
    @Sam If attached to other axis' plugs, both z-axis' steppers don't work. If turned by hand, the shaft of one of them doesn't even turn anymore (it is hard and blocked). Perhaps they was overused and they died long before the alleged 4 years of life given to a stepper.
    I didn't performed any current tuning: the only thing I did so far on the mobo is the implementation of the tl-smoothers. I'll try the E driver thing and let you know.
    @Laser Are you meaning that if I have to put new steppers which are wired differently, I must do all this?
  • Samuel PinchesSamuel Pinches Posts: 2,695Administrator
    edited September 3
    > If turned by hand, the shaft of one of them doesn't even turn anymore (it is hard and blocked)
    This jammed one does sound like it needs to be replaced. However, I think the other one should still be fine. If you connect two motors together in parallel (like the z motors are) then if one doesn't turn, then the other one will also not turn. So one faulty motor could cause both to become 'faulty'. I would suggest to try the other non-jammed motor on the other axis motherboard plugs, does that one work normally then?
    >Laser Are you meaning that if I have to put new steppers which are wired differently, I must do all this?
    For stepper motors, if they are 4 wire steppers, and have the same step angle (typically 1.8deg) then they should be compatible -- but, if the replacement is wired in a different way to the JGAurora steppers, you may need to swap two wires around for it to work. There is no official 'standard' for stepper motor wiring, as far as I know. So yes, you may have to check and change the wire sequence of the stepper motor. You can un-clip and pull out the stepper wires from the plug on the cable, and then re-insert the wires in a different sequence.
    Thanked by 1Matt
    Post edited by Samuel Pinches on
  • Richy_TRichy_T Posts: 138🌟 Super Member 🌟
    edited September 4
    Sorry I missed helping on this one. I had this problem early with my printer and it went away. It occurred again when I changed my motherboard out and it seems one of the internal wire connectors didn't have a good connection (it was jogged when I was putting the bottom plate back on). Reseating them solved my issue.

    To be more specific, the motors start wanting to go down when they're supposed to go up and/or move randomly. The key thing is that they do the same thing at the same time which indicates that it is not (likely) a problem with the motors. If these are not your symptoms then no worries.
    Post edited by Richy_T on
  • MattMatt Posts: 134🌟 Super Member 🌟
    @Sam I confirm that the good stepper works: plugged in the x-axis, it turns good. The other is completely gone.
    - The steppers: as for the new ones, the led lights up when its terminals are connected either in holes 1-2 or 3-4: if I attach the working old stepper to the same wires and I plug the led in the same holes, the led doesn't light up: it lights up when plugged in hole 1-3 or 2-4. This might mean that the new steppers have also their connecting slot which is differently placed than the old ones?
    Hi Richy. I didn't opened the case so far. In last resort I could do it, but for now I'll try the trial sequence starting from steppers, due one was found bad, and being connected in parallel as Sam said, they could be the most probable culprit.
  • MattMatt Posts: 134🌟 Super Member 🌟
    I bought a second steepper from the link you provided: hope it will work when it will arrive. Now I have 3 steppers which I cannot use anyway.
  • MattMatt Posts: 134🌟 Super Member 🌟
    Is the forum still alive?
  • Samuel PinchesSamuel Pinches Posts: 2,695Administrator
    edited September 16
    Unfortunately, not really, it seems. I'm considering closing it. 😞 View counts have dropped every month since april.
    Post edited by Samuel Pinches on
  • MattMatt Posts: 134🌟 Super Member 🌟
    I'm sorry for it. WIth closing this forum, any other references to jg machines will be lost.
  • michalko99michalko99 Posts: 21Member
    Hi Matt. Where did you put smoothers?Hopefully only on X and Y.
    Did you rotated stepper when disconnected from printer?
    You can test Z steppers like this: Disconnect shafts from them, press Home all axes and hit Z homing microswitch twice after X and Y axes gets homed. Then you can manually change Z position in menu. If they do not spin, power off printer, disconnect one motor and repeat homing procedure. After that do the same thing with second stepper. If problem persists, it might be problem with stepper driver. Which one is installed?
Sign In or Register to comment.