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UMO+ Woobling X block /sometimes Y


neotko
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Posted · UMO+ Woobling X block /sometimes Y

Hi

I'm really lost with this problem

giphy.gif

This was 3 weeks ago. Today I changed all the pulleys for 'really centered' ones. And the think it's that this appeared again. The X blocks (both sides) wooble up/down all-around.

3 weeks ago I fixed it by swaping the pulleys of order, but seeing that with this pulleys I have the same problem, I'm really lost.

If I unscrew the motor pulley and move the head, the problem shows. If I only unscrew the x4 pulleys (X side) the problem banishes. I did 3 times the X/Y alignment and it's perfectly aligned (as far as I can see/check). I also changed the X motor belt, since the one I had was really losen (sent by ultimaker).

Also, the shaft it's perfectly straight.

Anyone had this problem before and knows how to pinpoint a solution?

Thanks!

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    Posted · UMO+ Woobling X block /sometimes Y

    I just unscrew all. It woobles. Also released the motor so there's no tension from the short belt.

    I the bushing I think it looks okey. I also took out the 2 little tensioners of the belts. Woobling :S

    Btw I just installed a new head central block. But to remove that from the equation I took it out and left the central x/y shafts free. Woobling..

    I will start to change pulleys of order I suppose.

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    Posted · UMO+ Woobling X block /sometimes Y

    I really don't get it :(

    Changed all, checked the shafts again. Checked the bearings, cleaned everything again. And now it woobles just a tinny bit less. It's crazy.

    The only think I could see it's that it woobles more if the x motor it's tight (not much just enough so the belt isn't loose. :((

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    Posted · UMO+ Woobling X block /sometimes Y

    Well used the 2 sides of the bed. Ofc my bed it's banana too but one side I know it isn't because the print.

    This is what I did

    https://www.dropbox.com/s/87053fysd1xq3f4/Video-Bananabed.MOV?dl=0

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    Posted · UMO+ Woobling X block /sometimes Y

    Oh also originally I had the problem on Y but fixed it swaping pulleys. Now all the pulleys are new and almost perfect (not like the stock ones that 1 out of 3 clearly ain't straight). When I fixed Y it happens that X starter wobling. A week ago I fixed also that by again spawing pulleys. But now that are all new I really puzzled.

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    Posted · UMO+ Woobling X block /sometimes Y

    Holy mother of the banishing problem...

    Please if anyone can make sense into this because I can't.

    I was about to sleep just 15 minutes ago but because this problem was still bugging me I went to the printer.

    - Took the scres of x motor to loosen it. Moved x = woobly

    - Unacrewed pulley of the motor (the one on the shaft). Moved x = woobly

    - Unscrewed x4 pulleys on left and right shafts. Moved X = woobly

    Ok I tough to go sleep but well since I unscrew all and moved X many times I went to align the x again (sixth time today).

    Starter alignment. Fix the alignment clamps (the ones that are on youmagine that imakr printed me since they lost my wood align sticks). Clamp on left side. Got ready to align and sleep. Took the clamps out and because I'm a bit angry with all this I pulled up the right block up (not like mad but lifting it up for good). And then friking magic (because this doesn't make any friking sense). Now all the woobly have banished. It doesn't make fffff sense. Ok I did chill out. Got my alignment clamps. Aligned X and screwed all the pulleys back. Then moved x = perfect. Then screwed the motor pulley and x = perfect. Then pulled the motor down and screwed it for good and the friking x doesn't friking moves...

    So it's fixed. Again without any sense.

    My theorys now that I have chillout. Bearings where out of alignment and by pulling the right block up they when to an 'ok' position (nothing did sound when I did the lift up). Or maybe the right block it's not tight? (I did tight it for good after the 3 times I took the x/y central out to check if that was making this). So... Anyone have a clue? Because this it's solved but it doesn't make sense.

    Too be continue?

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    Posted · UMO+ Woobling X block /sometimes Y

    I put my money on bent shafts. This assumes the bearings are concentric to themselves. Are you checking in the same place along the shafts? The bearing centers couldn't have changed. I don't think the pulley shape or concentricity would cause the wobble unless they are way out of round, causing the belts to be tight in one position and loose in the opposite. When you slide the carriage, does it have smooth resistance throughout the travel, or is it cyclic easy/hard/easy/hard?

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    Posted · UMO+ Woobling X block /sometimes Y

    I remember having a bit of that hard/easy/hard/easy when moving the head by hand. That's what I took out the tensioners of the belts. Right now the tensioners are on and the movement it's easy/easy.

    One thing I forgot to mention on all the post it's that when one block woobled the mirror one also woobled. Now both don't. I also did check one rod stick to the other by hand rotating one and checking behind a light for open spots in between.

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    Posted · UMO+ Woobling X block /sometimes Y

    I don't believe it is likely to be eccentric pulleys. To really know, you have to do a verifiable straightness check. One shaft against the other is not that good. Ask yourself, what is the known starting point.

    When checking for true geometry and be certain of your findings, you have to start with something of a known quality. To do a real straightness check, you need a qualified surface to roll the shafts on (and measuring equipment if you want to quantify it). Best would be a surface plate at a machine shop. A quality machinist scale (name brand ruler, straight edge with a ground finish) could be used to check for light gaps. Short of that, you might consider a piece of ground marble or granite tile that can be purchases at a home supply store for cheap. Even with this, you are not assured of the flatness. You could check a couple pieces of ground stone tile against each other face to face.

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    Posted · UMO+ Woobling X block /sometimes Y

    Still. How the 'pull up' on the block explains that now it doesn't wooble at all?

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    Posted · UMO+ Woobling X block /sometimes Y

    Lot's of good ideas mentioned.

    Any chance you can video record the movement, sliding the print head around and the trouble spots?

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    Posted (edited) · UMO+ Woobling X block /sometimes Y

    Not really since now it doesn't move at all. And I prefer to keep it that way because when it was woobling (3weeks ago) it printed really really bad. I also just finished installing the magnetic head new version and it's printing soo nice. First time ever I can print a perfect robot. The woobling also occurred on all the Y positions and was 'stable' no more or less on any y position the x woobled the same. I'm starting to think that it might be related to the central x/y shafts that maybe wasn't properly fixed? I did reassembled this like 8 times on my umo+ live. It's so weird I'm afraid to touch it again to replace the belts for gt2 :S

    Edit. Now that I think that doesn't make sense since I also took off the x/y to see the wooble and it was there...

    Edited by Guest
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    Posted · UMO+ Woobling X block /sometimes Y

    Well the wibbly wobbly timey wimey it's back...

    It's very very small, but on tall walls it's making some marks on the prints even at 30mm/s

    Very boring video:

     

    Check the movement difference from the sideblock and the orange belt thingy.

    On the left side it's a little more noticeable, on the right side there's some, but even less.

    Things I'm going to try on the following weeks.

    - Change pulleys (again) and belts to gt2.

    - Change x4 bearings of the wobbly X

    - Change the shafts (all of them) to Misumi PSFJ8 (bough 12 shafts for 3 machines so hopefully they will be perfect..)

    /sulk...

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    Posted · UMO+ Woobling X block /sometimes Y

    Ok please. Pretty pretty please. Could anyone make sense of this?

     

    Now it wobble less? I pushed it counter when was down and down was was curving up. It just don't make any sense. I pushed it because did uninstall again all and assembled the x shaft (left) and the problem was still there. So I tryed what it shouldn't have do any effect (again like the last time that was wobbling much more)... And now it woobles less... The only I can think off its the bearings.

    I unplugged the central head shafts, pulleys and unscrew the motor to take the belt tension. Took out again the belt tensioners. Then because the problem was there still, assembled all back again.

    This is crazy

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    Posted · UMO+ Woobling X block /sometimes Y

    Does the whole shaft wobble, or just the middle? Or maybe is it worse in the middle? I think it is either bent shafts or eccentric ball bearings. Is this the machine you sourced yourself? These parts from China?

    Matt

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    Posted (edited) · UMO+ Woobling X block /sometimes Y

    It's true that when looking to the shaft it really seems like the whole shaft does wobble.

    This umo+ it's the one I bought preassembled from iMakr. I'm also talking with them but so far we didn't found the cause.

    Eccentric ball bearings. I suppse that could explain it. And when I push the shaft they somehow get a more aligned position? The thing it's that if one shaft wobble the mirror one also does so. Maybe the wood it's distorsioned and the bearings move and... I need to sleep on this and start to think about what else I could try.

    To check the bearings how could I do a proper test?

    Edited by Guest
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    Posted · UMO+ Woobling X block /sometimes Y

    Ok did pop out x3 bearings from the 2 extruders (to keep checking with ultimaker bearings).

    The problem seem to really be a banana shaft/rod.

    @dim3nsioneer it's this a proper method to check the shafts? I did lots of google but didn't found any proper way because the 'Find a flat surface' it's something quite imposible with the amount of crappy floor and ikeas. So.. I assembled 3 bearings on the shaft and while rotating them against the wood I observed the other side with a bearing to see the movement better.

    Checking left side

     

    Checking right side

     

    So it might seem that I have a banana

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    Posted · UMO+ Woobling X block /sometimes Y

    Best surface you can find for checking straightness of the rods are special stone tables for measuring machines.

    Second best surface is maybe a stone top of a kitchen counter. I tested my rods on such a stone.

    The test you made characterizes the whole system of the rod with the bearings. Which is not wrong at all as it is this system you use in your printer. If you have spare bearings you might test (by replacing a single bearing) which part of the system is actually the problem.

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    Posted · UMO+ Woobling X block /sometimes Y

    This three bearings are from the extruders. Also did more test with the bearings of my other to-be-assembled umo+. Also tested placing two bushings and one bearing at the end to see if wobbled and all did.

    I been reassembling the hole machine and testing all the shafts and changing all to gt2. 2 perfect ones, one really ok but not perfect and that one banana.

    Friday misumi shafts arrive so at least I will have hopefully, since I bought x12 shafts, some perfect ones. If then this shows I'll just go banana myself.

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    Posted · UMO+ Woobling X block /sometimes Y

    Just arrived the misumi shafts, open it, got 1 random, assembled it to 3 bearings, random, and it just does not move, not even a little, just pure and simple beauty. So case close after 56,58€x2+delivery in 12 shafts of sweet beautiful quality.

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    Posted · UMO+ Woobling X block /sometimes Y

    That's good news. Let's hope that cures it

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    Posted · UMO+ Woobling X block /sometimes Y

    Just finished changing all the shafts. Now nothing wobbles, everything moves so sweet. I wonder what oil misumi uses because all the shafts had some oil. I wonder if there's a industrial brand that's better than the sewing machine oil I got.

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