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Crashed It

Discussion in 'CNC Mills/Routers' started by Propgun_Studios, May 2, 2021.

  1. Propgun_Studios

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    Probably due to three hours of cleaning vectors up on a map, two cups of coffee and an additional 30 minutes figuring out why I was getting a T1M6 error (vectric decided to resort to GCode instead of GRBL). Been running great all week... amazing how easy it was to get set up and start making stuff....

    So I'd finished a roughing pass on a 2D relief map, basically a border and then water pocketed out from around an island which had the road structure engraved into it. Swapped to a ball tip bit, drove the machine back to zero but forgot to re-zero the z-axis. No biggie, I was testing the design in MDF anyway. Dragged the bit across the surface but it cut fine. Realized my mistake and aborted. By this point the bit had begun its descent into the material, so it's in maybe a half inch. My dumbass hits "Return to zero" thinking it will pick up the Z and head home. Nope - goes straight for home, snagging the well-clamped MDF and shattering the bit into four different pieces.

    Bring it home the right way, swap bits and inspect the machine. Lock rings holding the bearings on the X-axis have worked loose (it was mostly an X-axis move). Retighten all that, re-zero and start. Everything is looking good but when it makes a long run and then encounters material I get a slight 'hop' on the Z-axis. After verifying everything is tight (the router mount had two loose bolts) I test again - still hopping. Put a straight edge on the forward side of the X-beam and I have a tiny amount of wiggle, no longer flat. Whole Z/X gantry assembly wiggles back and forth. Travel at the bit tip is around 1/8" along the Y axis.

    Assume I murdered my X C-Beam. Everything else appears okay. Is this a likely failure spot for a crash like that? Seems like some other part would've failed first. Just wondering what else I should be checking.
     
  2. Kevon Ritter

    Kevon Ritter Veteran
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    Did you check the wheels?
     
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  3. Propgun_Studios

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    Stuck a screwdriver through them and rolled them around on the bench... no wobble or noticeable issues. Through-bolts appear straight as well

    Laying a straight edge across the face of ANY of the C-beams I get a slight wobble, so I'm not totally convinced that's my issue
     
  4. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    I think he meant the wheel adjustment mostly. Eccentrics tights all round. But not too tight.

    Basics of finding the issue:

    Disconnect the shaft couplers from the motors, and moving things, by hand. The human hands can detect movements smaller than the eye can see. Rolling, wiggling, pushing on the machine until you find where the issue comes from. Then address whatever is loose (like adjusting wheels there, or a bolt that came loose, or a stop collar that is not tight against the bearing etc)
     
    Kevon Ritter likes this.
  5. Kevon Ritter

    Kevon Ritter Veteran
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    Also check to make sure there is no physical damage. It's an extreme case, but the extreme wheels can crack under severe load.

    Make sure the lock collars on the leads are properly in place. Even a miniscule gap between the collars and bearings will cause the hop you're talking about.
     
  6. Propgun_Studios

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    Tore the X-axis down to just the C-beam attached to the riser. Took a three-hour break. Slowly reassembled everything. X-gantry assembly remained tight until I hung the Z assembly on it, then got the wobble. More I thought about it the more I figured a warped C beam wasn't the culprit. I'd adjusted the eccentrics before tearing it down but to no avail. On reassembly, I was **** about holding everything in place as I tightened the eccentrics. They're about set to full-tight, but everything is in place and snug, cutting correctly. Left a pretty good ding in the C-beam when it crashed. Chock it up to being a dumbass. Need to engrave a "Zero your Z-axis, dumbass" reminder into the fence.

    Thanks for the help.
     
    Peter Van Der Walt likes this.
  7. JustinTime

    JustinTime Veteran
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    LOL, I had a big sign on my monitor saying 'Zero Axis' and I still managed to not do it from time to time. :banghead: :banghead:
     

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