Nasty Y-axis vibrations
I'm getting terrible vibrating during printing that I simply cannot identify the source of. I'm hoping someone can suggest some things I can check to help identify the problem. Here's a link to a short video demonstrating the problem and also how it doesn't happen constantly.
https://www.dropbox.com/s/2utwobqpzit8dpg/2020-02-26%2019.58.58.mp4
It seems to happen mostly during infill and long, flat layers. Perimeters don't typically trigger the problem. Interestingly, during the first layer printing, the printer if virtually silent. I'm assuming that means speed is involved somehow, but I don't want to change all of my print speeds to super slow just so the bed won't vibrate. 🙁
I'm fairly certain the problem is with the Y-axis, but I've tried to adjust the rails and when I press on the belt during the vibrating times, it doesn't seem to change anything, so I don't believe tension is an issue. I've oiled the rails and the z-axis screws. I've also tightened the screws holding the print bed to the chassis. I'm not sure what else to do. Help?
RE: Nasty Y-axis vibrations
My opinions:
Never oil the rails other than a temporary measure. Use proper lubrication inside the bearings.
Never oil the Z-axis screws. It damages the Delrin trapezoidal nuts.
Never over-tighten those U bolts of death. They crush the bearing and cause binding.
Turn the machine off and move the Y axis by hand. Both directions should feel smooth with no binding. Not hitting anything like zip ties either.
Also run your fingers over those oily rails. You should just feel smooth - no grooves.
RE: Nasty Y-axis vibrations
I use lithium grease on the z-axis screws once-twice a year. I put a drop or two of silicone lubricant on the rails. "Oil" was really more of a lazy shortcut in speech. My apologies for the confusion.
I'll check out your suggestions once this print is done. It's also possible that screws at the back of the Y-rails need adjustment. I don't typically mess back there as it's impossible to get to them without moving the printer around.
The printer sees pretty heavy usage and has for some time. How often do you typically lube the bearings? I also haven't done anything with the u-bolts as again, that requires moving the printer.
RE: Nasty Y-axis vibrations
Has it been making that noise or did it just start all of a sudden? Did you change or do anything on the printer recently before the noise started?
I would guess it has something to do with the bearings. As Robert said, check the U bolts, the movement of the Y axis and the Y axis rods to make sure they are nice and smooth.
I use grease (left over mercedes benz wheel grease) on my Z axis screws a couple times a year, never an issue and nice and quiet.
RE: Nasty Y-axis vibrations
I believe the vibration has steadily grown over time, but the severity seems to have happened recently. I rebuilt the extruder recently, but didn't do anything to the Y-axis. I'll check the U-bolt and bearings tomorrow.