Crash Detection on my X-Axis on my MK3S  

RE: Crash Detection on my X-Axis on my MK3S

Have you Lubed the linear bearings?

regards Joan

RE: Crash Detection on my X-Axis on my MK3S

@joantabb

No I haven't. Do I need to disassemble the X-axis to take the bearings off and grease the bearing or is there a lube that I can put on the X-axis rod and slide the carriage over it to lube them?

RE: Crash Detection on my X-Axis on my MK3S

Maybe something is wrong with the linear bearings. Check for scratches, grooves... Also tightening torque of the screws on the back of the extruder.

RE: Crash Detection on my X-Axis on my MK3S

@karl-herbert

I will check when I get home but it would be hard for me to believe that the torque screws would be too tight (not saying they are not) but its just odd it just started 2 days ago while printing. Now I guess the bearing could have scratched the rod because there is definitely resistance when trying to move the carriage back to the left. However, I can move it to the right literally with easy. its just to the left its much harder to do

RE: Crash Detection on my X-Axis on my MK3S

@byhova

The Linear bearings have a dust  seal at each end, so those will tend to wipe any externally applied lubricant, to the ends of the smooth rods
If you use Light Machine oil, some will get past the dust seals and may reduce some of the friction, short term, but in reality, the best option would be to dissassemble and grease the insides of the bearings well. then reassemble

so if you had an urgent job, then temporarily externally lubricating the bearings may help short term...  but it's not a long term solution

grease applied externally will mostly get wiped off... 

Whatever you decide to do...  PROTECT your build plate from the Lube!

regards joan

RE: Crash Detection on my X-Axis on my MK3S

@joantabb

Good day! I am unfortunately in a similar position here with my MK3s - the seal on one of my upper-rod X-Axis bearings broke, the rod is caked with residue, and the extruder grinds to a halt when traveling leftward on the axis. It's also very difficult to move leftward manually by hand. The rods appear undamaged, at least. This is after several hundred hours of successful printing.

I need to replace the X Axis bearings, but I have been unable to find any guide for how to disassemble the X Axis just enough to get the axis off to replace the bearings. I'm hoping that the effort doesn't require disassembling the entire extruder housing or disconnecting any of the extruder wiring, just removing the Z-Axis ends, taking the the X-Axis of, removing the rods, pulling the bearings out, popping in new greased bearings and then reversing the above.

Is there a guide out there that I am missing, that walks through the process of MK3s X-Axis teardown and replacing the bearings?

RE: Crash Detection on my X-Axis on my MK3S

Al I can tell you is I took my bearings off with no major disassembly. Got the Z and X out at the same time.

You of course need to remove the four screws (maybe 5) in the back of the extruder that hold the bearings in.

After that, it is just a matter of seeing what part needs to come off next. Use the construction manual - lots of good pictures.

I think a key part was removing the screws from the trapezoidal nuts, to free up the Z axis.

I never touched any of the wiring. Entire job did not take over 30 minutes, not counting soaking the bearings in IPA to get out the old stuff.

RE: Crash Detection on my X-Axis on my MK3S

@robert-rmm200

Did you take the Z motors and smooth rods out from below in order to get the X Axis off? I don't see how to get the X Axis off the Z does without taking wires out, since the backplate has the wiring block the protrudes from the back that sticks well weyond the clearance for the top bar of the frame.

RE: Crash Detection on my X-Axis on my MK3S

Update: All fixed for me. I was told that I needed to unplug all connectors for the extruder from the motherboard and then I would be able to take the X Axis off without taking the sleeve off the wires and without removing the wire support black that extends from the backplate on the extruder carriage. This definitely was not the case, that would not work, not nearly enough clearance to get the X Axis past the top bar of the frame.

What I did was:

* Take the 4 screws out of the backplate and clip the zip ties on the upper rod of the X Axis.

* Take the end caps off the top of each side of the Z Axis and wiggle it as loose-open as possible without putting too much tension on the wire bundle.

* Take the smooth rods off both sides of the Z Axis. (This provided much less needed clearance for getting the X Axis off, since I then needed only to bring the X Axis up high enough to clear the threaded rods from the trapezoidal nuts.)

* Manually turn the Z Axis threaded rods to move the X Axis up as high as it would go (almost clearing the trapezoidal nuts).

* Gently pull the Z Axis threaded rods forward while turning them one at a time to fully dislodge the X Axis trapezoidal nuts from each side of the Z Axis one by one.

* Slowly see-saw each side of the X Axis, working them back and forth to clear the Z Axis threaded rods.

* From there, the normal steps, remove the belt from the carriage, remove the smooth rods and their bearings, replace the bearings on the rods after lubing them (did this for X and also for Z while at it), then reversed all the above to put it back together. Printing smoothly once again, maybe even better than when I first assembled in Nov.

It was a pretty involved process of a few hours, and a fair bit frustrating. This is coming from someone technically geared, but that doesn't do technical things like this very often. It be would be much easier for someone that does this sort of thing often and also knew the steps without sort of winging it. This is a pro - I don't need to do this stuff often because the printer is mostly fantastic.

I think this process would be significantly easier if the extruder carriage were designed to route all of the wires below the lower rod of the X Axis, instead of half above/half below. Even if it meant the carriage were a little wider, sacrificing a small amount of X travel.

If this were the case, then you could simply take the 4 backplate screws off, open the extruder carriage like a clamshell, clip the two zip ties from the upper rod, lower the entire carriage and all its wiring away from the X rods, and then easily remove the empty X Axis off the Z Axis, replace bearings, pop it right back on, slip some new zip ties on the carriage, replace the belt, andclose the clamshell of the carriage back over the X rods and bearings.

RE: Crash Detection on my X-Axis on my MK3S

Bit late - but maybe it will help someone else:

Strong warning for reassemblies - do not try to thread the threaded rods into the trapezoidal nuts while they are attached to the brackets.

Take the screws out of the trapezoidal nuts first, then spin them onto the threaded rods.

Otherwise you will cross thread those suckers. Not a pretty sight.

RE: Crash Detection on my X-Axis on my MK3S

Seams i have got the same issue now. After only some hour of printing :S

RE: Crash Detection on my X-Axis on my MK3S

I found what curse this problem and fixed kind of easy. 

Found this pipes that was beside etch other was a bit problem. they make different in presser.  The Other one was a loosing all screws back and take the two rodes out and test them and this was not the problem so i figure it must be something with mounting mekanism so i test put this back and press a little and wobbled and found soon a fit that diden't curse this problem. and put back the screws and now all working smooth again.

sorry for pore English. I am terrible bad in English....