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Solved Y-axis pulley removal

Discussion in 'Troubleshooting' started by Srmofo, Nov 26, 2016.

  1. Srmofo

    Srmofo New Member

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    I'm beyond frustrated with the unit I have sitting on my desk. Ive pretty much had nothing but problems from this unit since I got it in March and unfortunately all of it stems from bad QA processes (or lack thereof). Its a shame because the R1+ seems to produce good prints when it prints. For the record I have run less than 1 spool of filament through it. Every time I try to print I spend days getting it running so I let it sit rather than deal with it.

    So this is the first large print I've done on this unit which is why I believe I never noticed the problem. I first noticed some sluggish and stepper clicking sounds when it was at the extremes of the y -axis. I stopped the print and inspected. I found the belt was riding up the pulley and when it got to the extremes it was too much for the stepper which is where the sluggish and noise was coming from. I assumed I could just loosen the set screws and pull the pulley up the shaft to see if the belt would keep riding up or if just even out (aka the pulley was installed too far down) So I pulled the bed and as soon as I touched the pulley, the top of it fell off.

    Long story short,
    I need to now remove the pulley. Even after removing the set screws from the top the pulley would not come off. I thought I was being an idiot so I removed the stepper completely. This thing is firmly stuck on the shaft. It also appears the flats are not perfectly aligned with the holes. I'm still fairly new to these things , but I have worked with pulleys and steppers in the past and I seem to recall pulleys just sliding off (assuming no inference fit). Did I find another issue with this unit or are these things interference fit? I haven't modified any part of this other than adding a few LED lights into the hood.

    Any suggestions for getting this pulley off? I don't own a puller this small and wouldn't even know where to buy one. I would try printing one to see if it would hold up, but broken printer.

    I can't help but get this feeling that I received a defective unit from the beginning and it just rubs me raw t spend more time fixing it, rather than printing with it. If I wanted this headache I would have just built one and saved $600 20161126_204944.jpg 20161126_222701-1.jpg 20161126_221748-1.jpg Helping Hands tray multi holder 75° v1.png
     
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    You should be able to pry it off the shaft. A large screw diver would help with the flat of the blade between the bottom of the pulley and the face of the Nema-17.

    I am surprised that it is not just falling off since usually the problem is that they are too loose.
    Your suspicion of the flat misaligned sound like a fair guess to me.
    Worst case you can buy another gear cheaply on Amazon or RepRap, but I would give the prybar approach a shot first.

    edit: pretty sure those are Gt2 20t 8mm Pulleys
    (count the teeth to confirm)
     
    #2 mark tomlinson, Nov 27, 2016
    Last edited: Nov 27, 2016
  3. Srmofo

    Srmofo New Member

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    Well I had already tried the screw driver method very gently, but prying like that is bad for motors because you are pulling the shaft along with it.

    I ended up going out in the shop and quickly whipping up a very crude puller.

    After pulling this off with my tool I am certain that no amount of prying would have removed it from the shaft without destroying the stepper in the process. It was stuck.

    I couldn't get a clear picture of the ID of the pulley but you can see all the galling inside. I'm curious how they put it on when assembling my Robo. My guess is they just beat it on. What are the chances they have an installer large enough laying around?

    Now I have a new issue. It wont home. Look for the new thread

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  4. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    I am glad you got it off, don't try to ponder this too much since they are assembled in China by likely the lowest bidder.
    Most do not have the issue of them being too tight ... quite the opposite in fact.
     

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