I'm having some trouble with the Z-axis sticking when going up, and this is more common when the Z-axis is starting from a low point. There are sometimes small issues when going down, but it is more pronounced when going up. It is only the right side sticking, which causes the height to become imbalanced and then the left side sticks. Occasionally there is a small squeaking sound but I've not been able to determine where it is coming from.
Regarding the recommendations in (viewtopic.php?f=82&t=60931) I have done the following:
- Measured starting height of Z-axis with calipers to ensure starting straight
- Visual inspection of threaded rod, both straight
- Visual inspection of threaded rod, no damage.
- Placed threaded rod on brass nut and let it fall - rod falls smoothly through the nut
- Adjusted potentiometer voltage to 1.2v. No change
- Swapped stepper motors from left to right side and right to left side of z-axis. No change
- Filed the hole of Z-axis top mount (i3-08) to make a looser fit. No change
- Swapped threaded rods from right to left and left to right. This resolved the issue temporarily
I noticed that the two couplings that came with the printer are different styles (see attached) though the hole sizings appear to be correct so I am not sure if this could be the issue. I am out of ideas for what could be causing the issue, can anyone suggest anything else?
Z-Axis sticking
Z-Axis sticking
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- Capture.PNG (30.38 KiB) Viewed 8166 times
Re: Z-Axis sticking
The couplings should be the same type.
You can ask the sales to send you the replacement.
You can ask the sales to send you the replacement.
-Keep your mind and try to test it. 
-Everything will be fun！-Support all Getech printer.
-You can ask me the questions and I will kindly reply.
-Respect others is the best way you can get help!
-Everything will be fun！-Support all Getech printer.
-You can ask me the questions and I will kindly reply.
-Respect others is the best way you can get help!
Re: Z-Axis sticking
I replaced the couplings with two new ones I bought separately, as well as lubricated the threaded rods to ensure that they move smoothly using the 'drop test'. I also filed out the hole in the acrylic a little more to make sure it was rotating smoothly.
The z-axis is still not moving correctly and getting stuck on one side. I'm giving up on this printer as simply not working and now I have bought an Ender 3 to print instead
The z-axis is still not moving correctly and getting stuck on one side. I'm giving up on this printer as simply not working and now I have bought an Ender 3 to print instead
Re: Z-Axis sticking
Hi Kaladorm,
You say you lubricated the threaded rods... What about the linear bearings on the 'Smooth' rods ?
If there's one thing I wish I'd done whilst building my machine rather than have to take apart and do afterwards...
It would be to tell myself "Take the linear bearings and put some '3-in-one' (It's a very light lubricating oil, common in the UK, NOT WD40 !) into each one before you build the machine"...
The difference is amazing...
To me it was a squeaky X carriage that was prone to more than a few layer shift errors...
Pour the light oil into the bearings - re-assemble... Chalk and cheese... Silent sliding and an end to layer shifting...
Now I know that the Z axis works the same way on rods... Hence I did all 3 axes at the same time.
Silent running - Except for the annoying cheap fans !!! (I'll get to them one day)
You've bought a replacement printer already... But you could always sell the other should you get it working by lubricating the linear bearings for a few pence... (OK you have the pain of getting the lub' into the right places !)
- Now you may have done this already - just that your posts were concentrating on the threaded rods... They should be free to wobble and they just provide force up/down... It's the linear bearings and smooth rods that provide the guidance, accuracy and keep the X axis going up/down smoothly on the Z axis.
Gerry
You say you lubricated the threaded rods... What about the linear bearings on the 'Smooth' rods ?
If there's one thing I wish I'd done whilst building my machine rather than have to take apart and do afterwards...
It would be to tell myself "Take the linear bearings and put some '3-in-one' (It's a very light lubricating oil, common in the UK, NOT WD40 !) into each one before you build the machine"...
The difference is amazing...
To me it was a squeaky X carriage that was prone to more than a few layer shift errors...
Pour the light oil into the bearings - re-assemble... Chalk and cheese... Silent sliding and an end to layer shifting...
Now I know that the Z axis works the same way on rods... Hence I did all 3 axes at the same time.
Silent running - Except for the annoying cheap fans !!! (I'll get to them one day)
You've bought a replacement printer already... But you could always sell the other should you get it working by lubricating the linear bearings for a few pence... (OK you have the pain of getting the lub' into the right places !)
- Now you may have done this already - just that your posts were concentrating on the threaded rods... They should be free to wobble and they just provide force up/down... It's the linear bearings and smooth rods that provide the guidance, accuracy and keep the X axis going up/down smoothly on the Z axis.
Gerry
Re: Z-Axis sticking
Thanks Gerry, some more great tips there. I did also lubricate the smooth rods, though already did it with WD40 not the 3 in 1 you suggested. Any particular reason I should avoid WD40 by the way, I'm curious?
What's happening is on raising (sometimes falling) one side starts to stick, when that happens the Z-axis gets slightly misaligned which I presume then puts more pressure and then makes it even harder to shift. It moves fairly freely with the steppers off - it's a little grindy if I turn the couplers with my fingers, but the threaded rod goes through smoothly and if I take both threaded rods out it slides fairly smoothly up and down the smooth rods.
The only thing I could think is that the frame is somehow misaligned and is slightly bowing inwards, meaning once the axis first 'catches' it is then harder and harder to move it until I manually realign again.
What's happening is on raising (sometimes falling) one side starts to stick, when that happens the Z-axis gets slightly misaligned which I presume then puts more pressure and then makes it even harder to shift. It moves fairly freely with the steppers off - it's a little grindy if I turn the couplers with my fingers, but the threaded rod goes through smoothly and if I take both threaded rods out it slides fairly smoothly up and down the smooth rods.
The only thing I could think is that the frame is somehow misaligned and is slightly bowing inwards, meaning once the axis first 'catches' it is then harder and harder to move it until I manually realign again.
Re: Z-Axis sticking
Hi, you can check if the threaded rods of the left and right shafts are bent and the threads are aligned.
-Keep your mind and try to test it.
-Everything will be fun！-Support all Getech printer.
-You can ask me the questions and I will kindly reply.
-Respect others is the best way you can get help!
-Everything will be fun！-Support all Getech printer.
-You can ask me the questions and I will kindly reply.
-Respect others is the best way you can get help!
Re: Z-Axis sticking
Hi Kaladorm,
No particular hatred of WD-40 here - I was making the point that '3-in-one' is not an equivalent to WD-40.
Though I would note that WD-40 is over used as a lubricant. Sure it's great for many things, but as a lub' it soon requires replacing.
A genuine light oil is often preferable.
If your frame was bent or misaligned, then when you removed the threaded rods, I think there would still be some positions where you'd feel resistance when manually sliding the X axis assembly up and down on the Z axis. The smooth rods would also be misaligned ?
If they're working fine, then I'd check to see why the threaded rods are fighting against them.
You say all is well when sliding up and down with the threaded rods removed... I agree that it follows that the threaded rods are somehow at fault.
If the threaded rods were anchored to the stepper motors directly, then you'd have to get all four rods (2 threaded, 2 smooth) all precisely vertical and parallel to each other... Hence the 'Bendy' in-line connectors. These should free up the requirement of the threaded rods being so precise.
You don't say what type of threaded rods are in use. I'd certainly recommend T8 lead screws rather than 'Standard M8 x 1.25mm threaded rod'.
They're readily available and pretty cheap on Ebay/Amazon.
When I fitted these to mine (Bought and fitted during 1st assembly), I note that I had to ease out my stepper motor connectors with an 8mm drill.
- You also have to change the steps per mm line in the configuration.h file in the Marlin folder.
I'd have a play with rolling all four shafts along a flat surface as this tends to highlight any wobble problems. It doesn't highlight any thread issues though. - Hence I'd have T8 leadscrews as they're less likely to be at fault, and any thread issues would be more visible.
No particular hatred of WD-40 here - I was making the point that '3-in-one' is not an equivalent to WD-40.
Though I would note that WD-40 is over used as a lubricant. Sure it's great for many things, but as a lub' it soon requires replacing.
A genuine light oil is often preferable.
If your frame was bent or misaligned, then when you removed the threaded rods, I think there would still be some positions where you'd feel resistance when manually sliding the X axis assembly up and down on the Z axis. The smooth rods would also be misaligned ?
If they're working fine, then I'd check to see why the threaded rods are fighting against them.
You say all is well when sliding up and down with the threaded rods removed... I agree that it follows that the threaded rods are somehow at fault.
If the threaded rods were anchored to the stepper motors directly, then you'd have to get all four rods (2 threaded, 2 smooth) all precisely vertical and parallel to each other... Hence the 'Bendy' in-line connectors. These should free up the requirement of the threaded rods being so precise.
You don't say what type of threaded rods are in use. I'd certainly recommend T8 lead screws rather than 'Standard M8 x 1.25mm threaded rod'.
They're readily available and pretty cheap on Ebay/Amazon.
When I fitted these to mine (Bought and fitted during 1st assembly), I note that I had to ease out my stepper motor connectors with an 8mm drill.
- You also have to change the steps per mm line in the configuration.h file in the Marlin folder.
I'd have a play with rolling all four shafts along a flat surface as this tends to highlight any wobble problems. It doesn't highlight any thread issues though. - Hence I'd have T8 leadscrews as they're less likely to be at fault, and any thread issues would be more visible.