MK3S - Y-Axis Crash Detected During Smaller Prints
I just finished building my MK3S a few days ago. The printer is amazing and made it through the entire setup without the printer showing any issues. However, I seem to be getting a lot of y-axis crashes for seemingly no reason.
This only happens on smaller objects that have a small radius for the extruder to move around. For example, it often crashed when printing a spool holder rod and on Benchy's cabin. When it happens, I check the print for any spurs or over extrusions that may have occurred, but can't seem to find anything.
I've checked my belt tensioning (X: 263/Y: 262), plate slides smoothly along the Y-axis, and the belt doesn't appear to be pulling to the left or right. I'm out out ideas.
Has anyone else had this issue? Any ideas on how to resolve it?
RE: MK3S - Y-Axis Crash Detected During Smaller Prints
Crash detection is an instant over~current detection feature, make sure nothing is binding/dragging etc but I'm sure you have already!
RE: MK3S - Y-Axis Crash Detected During Smaller Prints
Yes. I've been looking for anything catching, but really cannot see it. I've even been watching the extruder cable and bed cable closely to see if there's even a remote chance, but it certainly does not appear to be either of those.
RE: MK3S - Y-Axis Crash Detected During Smaller Prints
My numbers are 295 and 296. I have high belt tension but very low friction in X and Y, and friction is what the "belt tension" numbers tell you. They really don't provide any useful belt tension info.
Friction: bearings that aren't lubricated will cause crashes. Add some grease or oil to the rods, moving the bed and extruder back and forth trying work the grease past the seals and to the ball bearings inside. A drop or two at a time, and eventually you'll feel the bearings start rolling smoother. It also helps with stiction, which is what your printer is probably suffering (force needed to get the bearings moving).
The oil that ships in the bearings isn't really a lubricant, it's more an anti-rust agent. The bearings and rods need grease for longevity.
Also Y-Axis bearings can cause problems if you over tighten the U-bolts holding them. All you need is snug, not tight, just enough to keep the bearings from moving. Anything tighter can deform the bearing shell.
RE: MK3S - Y-Axis Crash Detected During Smaller Prints
Awesome. Thanks for the reply! I'll certainly give this a shot. Do you have a recommendation on a lubricant for the bearings? I have WD40 around the house, but I'm not certain that's ideal for these bearings.
Side note, would it be smart to use some on the extruder bearings as well?
RE: MK3S - Y-Axis Crash Detected During Smaller Prints
Misumi recommends packing their bearings with Grade 2 lithium grease before installation. But the engineer I spoke with said even car motor oil is better than nothing. I use Superlube synthetic with Teflon. but there are pros and cons to the Teflon. Any auto parts or hardware store will have the lithium and Superlube in small tubes for about $5.
And yes, all moving parts EXCEPT the lead screw. The Delrin T-nut is self lubricating and may be damaged with some greases. The large teeth of the Bondtech filament drive also need a dab of grease (use a small paint brush and apply a thin coat to the idler teeth).
RE: MK3S - Y-Axis Crash Detected During Smaller Prints
Just an update on this. I lubricated all 3 axis bearings, while the crashing has significantly decreased, I still have maybe 1-3 crashes per print (especially with Benchy, oddly) however, they're never consecutive enough to have the print fully stop. You can however see exactly where the y-axis crashes occur, as the prints have a distinct small shift on that layer, which is frustrating.
Should I keep adding a little lubricant to the axis (a drop at a time as Tim suggested), or is there anything else I can try? I'm not certain if over-lubrication is something that can occur with these bearings, although I'm certain dust collection can occur.
RE: MK3S - Y-Axis Crash Detected During Smaller Prints
What I noticed during assembly of my Mk3S was the 7 linear bearings had a seal type retainer on each end and after the fact I carefully removed rods and applied the recommended lubricant. Did not have any "Crash Detection" errors prior to follow~up and so far none to date.