So the printer I use at work is an ultimaker 2 extended + (or something like that) and for the longest time I’ve been having this weird (but tiny) issue with the Z axis. The sides of parts appear to be slightly “wavy”. Any idea why this is happening? My theory is that it’s the grease on the lead screw. Yes grease. Someone before me lubed it with grease. So I’m thinking that maybe some of the grease has hardened slightly over the last 3 years and it’s making the build plate move up at just slightly different layer heights and that’s causing the plastic to squish together more or less. Other than that I’m not sure. It just makes the parts not look quite as nice or hold as tight of a tolerance. Also, this part is .5" tall and apparently it’s levitating…
I doubt if it’s the grease. Maybe just lower resolution settings or worn parts. My prints usually look like that because of my cheap printer. By the way, you can easily remove the old grease with varsol or possibly paint thinner.
Try cleaning off the grease with a paper towel while you rune the bed up and down. Get in the crevasses.
Then reapply a small amount of amount of Magnalube (our UM2E came with a small tube of this stuff).
For a part that small you might want to print multiples at a time to keep things from heating up too much.
Also check your X and Y rods. Mine get “sticky” over time. I have no idea why. It makes no sense. I have to wipe them down with acetone every once in a while and then reapply a small amount of Sewing Machine oil.
Check belt tension on x & y axis drives.
It’s worth cleaning that Z-axis even if that’s not the ultimate cause.
Actually WD-40 is great for cleaning off grease. It’s a lousy lubricant though so get something good to lube the threads with after they’re clean. As for what, I won’t get into that hornet’s nest. ;’)
You could be having temperature “swings”, some UM2 machines are a bit prone on having an unstable PID controller, causing temperature swings, which can cause the exact problem you see.
Keep an eye on the temperature in the tune menu while it is printing.
(Difference in temperature causes difference in extrusion, causing this artifact)
We never had issues with the grease on the Z axis, other then it collecting dust for some people. But in general, lack of grease, or problems there, result in different artifacts.