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Z Wobble

itisnot_meitisnot_me 🌟 Super Member 🌟 Posts: 82
As you might know the z screws are not straight on the A5. With that it does create z wobble. While not a show stopper I have been dialing in my A5 to be as perfect as possible. I am getting so great prints but it seams like my last thing to fix.

So, does anyone know of a successful method where they almost completely eliminated z wobble? Some people have add on mods that hold the tops of the screws close to in place but idk how well that works with the screws still bent.

Comments

  • Der_MuckDer_Muck 🌟 Super Member 🌟 Posts: 238
    For what do you wanna fix it? When the bearing is straight the Z wobble doesnt infect anything at all.
    You can try to unlose the screws of the Z motor a bit, set Z0 and than screw the screws thight. That should center the motor little more. I only have a little wobble when Z is on the ground with that now.

    Dont mount anything on the top there, you will get some force on the bearing and that effect the print.
    There is no bending, I think its the gab in the thread of the brass bushing and the flexible clunch of the motor.
    So one side has to be free, thats ok and what the chinese engineers thought.
  • itisnot_meitisnot_me 🌟 Super Member 🌟 Posts: 82
    I would like to stop some z offset/banding/wobble that happens on prints. mine it not really all the bad but I am working for perfection on my prints.
  • Der_MuckDer_Muck 🌟 Super Member 🌟 Posts: 238
    Did you change the bearings on Z? And did you use right lube for the thread and the bearings? The original lube is to sticky, change the blue lube to a litium base fat or a PTFE oil.
    Normaly the light wobble of the Z thread doesnt effect the print. I would try to center the motor as I wrote, that can reduce the wobble. If you have bad wobble, maybe the flex. clunch is not good any more. 
    The system of the JG has its limits of quality and accuracy, a round 8mm bearing is never so accurate as a linear guide.
    But again, the wobble is caused of thread clearence. If you can find the right position of the motor, the screw drive will be centered and the wobble is reduced to a minimum. A change to a ball screw drive is not passible because of the build size and its to expensive for that printer.   Its more to use in a self build printer unit in combination of a linear guide. 
  • itisnot_meitisnot_me 🌟 Super Member 🌟 Posts: 82
    I can try you relube the threads and lube the rods. For the threaded do i need to do something special to remove the current stuff or just apply more on top.

    I currently have this one 


    I did not change the bearings on the z and only have on X. dang it was such a pain to change it out though. Thought i was going to break 

    I mean my prints are pretty dialed in but there are sometimes that that i see the shifts. I believe i have too high of standards. You can see below the slight lines that i am talking about. 

  • Der_MuckDer_Muck 🌟 Super Member 🌟 Posts: 238
    That is not the fault oh Z wobble, its can be that a bearing is to tight to move freely or a sticky lube.
    I used PTFE spray on the thread to weak the blue orig. lube and than wiped it away. After that I used universal lube. 

    Is it PLA you print? It looks like nothing comes out of the nozzle. Try a retraction test with Z hop than you see what your problem is and if the settings are ok: https://www.thingiverse.com/thing:909901

    The layers should be look very equal to the others and the tip should also look very nice with PLA. Try to break the tips to see the layer adhesion. After ajusting you will have much higher quality.
  • itisnot_meitisnot_me 🌟 Super Member 🌟 Posts: 82
    Alright so i was thinking that maybe my issue that i have could come from the bed movement. 

    Do you think that if i was to secure the bed without springs and made it stationary that I could reduce the thing that I call wobble on the print. I mean I already have the bl touch installed and it auto levels on every print. so i do not see why the springs are needed.

    this is a closeup of the latest print https://photos.app.goo.gl/u4BQBW8FQa1VjREf7

    Like i mentioned its not a show stopper and is shown more on pictures that in your hand, but its something that i want to reduce so i get cleaner prints
  • Samuel PinchesSamuel Pinches Administrator Posts: 1,623
    edited March 28
    I'm very certain that some of this wobble comes from the long springs and screws that the bed is mounted on. I replaced these on my A5 with solid nylon spacers, which meant I could tighten the thumbscrews, making the entire bed very solid. That improved my print quality. However, you will need to find the right height of spacer for your bed. I just use mesh bed levelling to compensate , and I keep my bed fixed in place.

    If you have a bltouch I think you have the perfect opportunity to try it also.
    Post edited by Samuel Pinches on
  • itisnot_meitisnot_me 🌟 Super Member 🌟 Posts: 82
    how much clearance would i need for the bed to the the case?
  • Samuel PinchesSamuel Pinches Administrator Posts: 1,623
    I think you need a minimum 8mm spacer... not sure what that works out to be though.
  • itisnot_meitisnot_me 🌟 Super Member 🌟 Posts: 82
    I had the spring compacted to about 10mm and it was either rubbing on the top of the case or very close. I think that if i have about 16mm spaces in place of the springs it might be enough clearance to not drag on the top of the case. I will head out later to try to find some
  • beatabeata Member Posts: 9
    I have an (admittedly tidy) scratch on my top cover due to lowering the bed too far. I'll have to give this a try too.
  • itisnot_meitisnot_me 🌟 Super Member 🌟 Posts: 82
    edited April 27
    @beata I found that the 1/2" nylon spacers from Lowe's worked but you either need a bltouch (or some bed leveler) or you need to modify the z endstop switch lower to account for the height difference. Though I didn't see a difference in the wobble that I have seen I think it's more baked into the machine as it's in the same spots every print
    Thanked by 1beata
    Post edited by itisnot_me on
  • beatabeata Member Posts: 9
    A quick measure with the springs removed, between rail and bed, raised with craft magnets, 16.5mm - 18mm. 5mm clearance between bed and top of base. With the out-lier in the same corner I had trouble with previously.

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