Slipped coupling, X-Axis crooked on one side
Tried to diagnose this one on my own after my last silly error, but can't seem to find an answer as to how to fix it.
Fired up the auto-home and things actually started moving which was great. That said, my bed missed the stop as I've had trouble getting it to stay put. After the bed stopped going back, the head came down, but when it finished it was past the glass. I know that can be easily remedied, but when I took a closer look I noticed the X-Axis is crooked on one side. The left side is a little higher than the right (enough to notice) and the coupling on the left side has slipped up whereas the one on the right stayed put.
Not really sure how to go about fixing this, so any help would be appreciated. I'm sure it won't be the last issue I have from a mistake I made in the build, but that's part of the process of learning 🙂
Re: Slipped coupling, X-Axis crooked on one side
Hi,
first make sure you have enough room in Z derection, if not turh the threaded rods so that the X carriage moves up (use LCD or pronterface).
Hold the shaft of the motor and screw in the threaded rod., And put on the threaded rod heat srink tubing using lighter. it will further tighten up the joint.
Re: Slipped coupling, X-Axis crooked on one side
Hi Adam
Have you put the heat shrink in place? You need to push the threaded rods down as far as possible, then make sure the heat shrink is overlapping slightly at each end, then thoroughly shrink it.
You will then need to calibrate each end of the X axis to the same height - you need the same height from the Y rods or the Y chassis frame - not the bed.
Peter
P.S. I had a similar issue; I ended up with aluminium couplers instead of the tube/heat shrink; but they come with their own problems...
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Slipped coupling, X-Axis crooked on one side
I actually mis-worded things a bit. The coupling didn't twist up, I don't think I ever fully had it down to begin with as they were really hard to get down. That's probably what knocked things out of whack... it took about 30 minutes for me to get them on initially.
Good news is I followed your advice and now have that one all the way down as shown in the photo below. It's super snug, so the heatshrink I forgot about will probably cinch that up nicely for now.
That said, I'm a little confused about adjusting it. I was under the impression that when I first ran the printer and did "Auto Home" I would calibrate things through that? Was just following the book instructions for the first use after I got the wiring issue fixed and assumed I would just need to do that again, then follow the next steps the book lines out for loading filament, etc.. etc... The only thing I did was the Preheat before Auto Home as that's where it went wonky due to backwards plugs.
Here's another pic of the top, you can kind of see how much it's off. Think the right screw is about 3mm higher than the other and both are touching the motors. Was smooth when I ran it back up manually through the LCD, just not even at the top and not calibrated
Re: Slipped coupling, X-Axis crooked on one side
Adam
There is no use trying to print with the (say) right hand X axis 10 mm higher than the left... The frame will be twisted and you cannot expect decent prints.
When you get the connectors fully home and the heat shrink shrunk - with at least 3mm (1/16") overlap on top and bottom, you will need to make sure that each end of the X axis is levelled to the Y axis. You do this by turning one of the motors; you will have to hold the other motor to stop it turning as they are wired in parallel and the one you turn by hand will act as a generator...
You only need to get the level to within 1 mm; it's not difficult to do if you have a digital vernier or even steel rule. Measure from the top of the top X rail to the Y rail on one side of the printer and the same on the other side. Get the two measurements about the same by turning one of the Z motors and then you use the bed calibration screws to do the final levelling.
Hope this is understandable...
Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…
Re: Slipped coupling, X-Axis crooked on one side
Again, thanks for the tip. I totally got what you were saying, and was able to lower that gap and seal it up tight with heatsink. Tried a few test runs, and that part of the machine seems good to go now.