cracked parts :(

This topic contains 22 replies, has 4 voices, and was last updated by  David Walling 1 week, 3 days ago.

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  • #108461

    David Walling
    Participant

    Hit a snag while working on my latest project.

    I was noticing that I was getting really nasty chatter. I kept adjusting my feeds and nothing was helping. Yesterday I took some time to go tighten up some bolts as it looked like the XY gantry was wobbling.

    When to tighten one of the bolts and saw nothing but cracks around it.

    Looks like I’ll be printing a new gantry soon.

    Attachments:
    #108464

    Barry
    Participant

    Waaaay too tight!  😁

    #108465

    David Walling
    Participant

    Waaaay too tight! 😁

    Original parts from when I built the machine almost 2 years ago. This picture was taken BEFORE I went to put a wrench on them.

    #108468

    David Walling
    Participant

    This brings up questions, though…

    What parts do I need to print to replace the entire XY with the new Burly parts? Will the new Burly parts still work with the old leadscrew setup?

    #108492

    Ryan
    Keymaster

    You need all the center and Z parts. Lots of printing, super worth it, promise!

    #108754

    David Walling
    Participant

    Started printing the z parts and a new spacer this morning.

    Then I have the two XYZ and XY parts to print. If I run the printer continuous, it should be done by tomorrow evening. Hoping to start the install this weekend.

    One question never answered… will I still be able to us the threaded rod parts? I never switched over to the lead screw setup.

    #108794

    David Walling
    Participant

    New z-axis parts complete.

    Here’s the time-lapse of the parts printing:

    #108851

    Ryan
    Keymaster

    will I still be able to us the threaded rod parts?

    Shoot, no. Or at least I never made a nut holder for it, that is all that is needed to make it work, without switching.

    #108852

    David Walling
    Participant

    Then I assume my nut holder won’t fit on the new design… 🙁

    #108854

    David Walling
    Participant

    Looking at the design. I think all I need to do is modify the spacer to embed a nut into it. Then wedge the nut in the spacer using the XYZ bracket to brace the other side of the nut.

    #108857

    Ryan
    Keymaster

    Exactly, if you are using the previously recommended nut or the one that came with my kit it should just fit (I think). It will not work with the longer ones some people were using, that is the whole reason I didn’tt make that pocket nut shaped.

    #108859

    David Walling
    Participant

    Well. I guess we’ll see which nut holder I have when I start assembling the new gantry. Worse case, I’ll design a new one and put it up on thingiverse for us ‘retro’ guys still holding on to out dated technologies.

    #108862

    David Walling
    Participant

    Haha… awesome… 10 minutes left on the end of a 3 hour print and the power flickers enough to reset the machine. First time that’s every happened. Maybe I should get a UPS for it.

    #108956

    David Walling
    Participant

    Got the XYZ parts printed.

    Just need to print the two XY parts now

     

    #109059

    David Walling
    Participant

    Got the last XY part printed last night. My little, highly modified, Geeetech Aluminum printer has been really consistent with PLA lately. I’m hoping I can get the gantry swapped out this weekend, but I also want to get a new workbench built. Not sure I can get to both projects.

    #109064

    Barry
    Participant

    I need to try to print one of these(smaller) parts at .02mm just for giggles.

    #109126

    Bill
    Participant

    Sounds like someone has too much time on their hands…

    #109154

    Barry
    Participant

    Sounds like someone has too much time on their hands…

    Well, I can crank up the speed a little.  Still waiting for a new extruder stepper.  The e3d stepper I have is a little underpowered.  You need a really flat build surface though.

    • This reply was modified 2 weeks ago by  Barry.
    #109182

    Barry
    Participant

    20190810_111529
    .2mm on left, .02mm on right.  Took 45 minutes.  I messed up on the .02 with the top shells.  Should have told it 2mm, not 2 layers.

    • This reply was modified 2 weeks ago by  Barry.
    • This reply was modified 2 weeks ago by  Barry.
    #109376

    David Walling
    Participant

    Almost have the gantry swapped out. You can see where the old pieces cracked over time. That would explain the issues I’ve been having with chatter and a semi-loose gantry.

    All I have left to do is solder the steppers back together, square up the gantry, and re-tension the belts. I need to stop and buy some zip ties on the way home for that.

    Good news is… The old nut holder for the threaded rod fits the new burly parts.

    #109570

    Bill
    Participant

    Of course you really need to look into hitting each version with a big hammer to see if the strength has changed… 🙂

    #109593

    Barry
    Participant

    Were all the bolt holes tight when you originally built the machine?  Looks like all the cracks are in line with the bolt holes.  I’ve not heard anything about pla shrinking over time.

    #109596

    David Walling
    Participant

    Here’s my working theory… and I have no way of backing it up.

    What I think happened is one of the parts cracked from me slamming a bit into something or over-stressing the machine. I can think of more than one occurrence of said case.

    Me, in my infinite wisdom, decided that the bolts needed to be tightened because the gantry was now wobbling. Me thinking that a bolt loosened over time, and not thinking about a part being cracked. So I started tightening things. I probably over-tightened something that caused un-due stress on other parts of the machine. The next time I either hit something or tried to cut too fast, it probably caused the other cracks.

    I do know I had to use a screwdriver to get two of the bearings out because the part was deformed and had tightened. I think it was the two tension bolt A’s.

    The device was also living in my Texas garage where temps would get above 100*F. There’s a chance that the PLA got soft at some point and allowed any bolt tension to slightly deform the part over time.

    Like I said, these are the original parts from over 2 years ago.

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