What causes the RM2 to go out of calibration?

[EL Cuajinais]

Ok that is twice now that my printer has gone out of calibration in as many weeks. I can see the first layer is really squished in some areas and normal in others. First time this happened to me was after I removed the glass bed and put it in the freezer. So I figured it had to do something with that, even though I have it marked to install it exactly the same way every time. And I install the binder clips in the order stated in the manual...

Now it has gone out of calibration again, but this time, I've not removed the glass at all since re-calibrating it. So can anyone venture a guess as to what is going on?

Thanks.

[KAS]

On a new build I would go over everything and re-tighten the screws. After a week on mine, the end stops started coming loose and that caused craziness with calibration.

[BenTheRighteous]

I've been bitten more than once by loose cheapskates. Make sure they are snug against the rails.

[EL Cuajinais]

Thanks for the excellent suggestions. However, the limit switches and cheapskates were all snug.

[Mac The Knife]

when all else fails, blame the humidity.

[Eaglezsoar]

I try to use the blue Loctite on all the screws, it helps to keep them tight but they can be removed if necessary.

[bot]

I've noticed an increasing amount of play on the arms where they meet the acetal u joints. The holes seem to have (or always have been) slightly oversized on the end of the arms, causing play.

[stonewater]

what did you do to bring it back into calibration? if the answer is nothing then I had the same problem... for me it was the nut that holds the extruder hot end to the plate that bolts to the effector. It took a little bump and it would move enough that the layers would be off.

ya just gotta check everything again.... is your machine spitting black dust? may have a tooth on the belt that isd wonky... or the belts may be loose. electromechanical machines.... its like working on a pinball! seemingly unrelated things can cause problems.

Tom C

[KAS]

I've noticed an increasing amount of play on the arms where they meet the acetal u joints. The holes seem to have (or always have been) slightly oversized on the end of the arms, causing play.

Also to go with Bot's suggestion. On the inside of the arms, you'll notice a bit of casting/seam lines that might need to be sanded down a bit.

[EL Cuajinais]

I found the screws that go through the metal spacers to fasten the hot end to the effector could be tightened quite a bit more. I think I may apply the blue thread lock to everything as suggested. As for the belt tension, this is something that does worry me, I do have a small amount of black powder on tower bases and on top of the cheapskates. I have them pretty tight as I think if there is any give when the belt switches direction the print quality will suffer. Are you in agreement I should see no powder at at? I think that is what the manual says but isn't there some break-in period for the belts? I have a total print time of 2 days and 17 hours.

Thanks again everyone.


EDIT: Forgot to mention. The second time I calibrated the printer I just did it with the end stop screws, not the whole EEPROM thing. It wasn't as good as the first one, but I figured it would tide me over until I get the PEI for the base and have to do a formal calibration all over again.

[BenTheRighteous]

Ideally, you just do the "whole EEPROM thing" once and then never touch it again, unless you put different length arms on your machine someday or something else along those lines.

[KAS]

It's hard to align the top and bottom pulley to run parallel. This causes the belt to track to one side of the bearing and usually ride the extrusion. It's possible you might need to file a deeper chamfer or look for burrs that could be scraping the belt. OR you can try to align the top idler bearing to find that nice sweet spot where the belt rides the middle. That's tricky to do while keeping tension on the belt.

[EL Cuajinais]

Ideally, you just do the "whole EEPROM thing" once and then never touch it again, unless you put different length arms on your machine someday or something else along those lines.

I suspected this could be the case but since I hadn't heard anyone mention it... Thank for letting me know!

It's hard to align the top and bottom pulley to run parallel. This causes the belt to track to one side of the bearing and usually ride the extrusion. It's possible you might need to file a deeper chamfer or look for burrs that could be scraping the belt. OR you can try to align the top idler bearing to find that nice sweet spot where the belt rides the middle. That's tricky to do while keeping tension on the belt.

I'll look into this. Thanks everyone! This forum is extremly helpful!!!