relmendorp

Bearings have been replaced, ordered them through UM support. Quality of walls have increased greatly. Still not perfect, but quite good. I think this print was a bit too warm. 0.1mm layer height.

That's a nice manual! Did not know it existed. Unfortunately it's not just assembly, taken apart, the bearing does not operate smoothly. These bearings are not expensive. http://www.ebay.com/itm/LMK12LUU-Square-Flange-Mounted-Linear-Motion-Ball-Bearing-12mm-/141075812645

I've removed the Z motor, screw and bolt in the platform. Cleaned it and greased it, but that did not help. I noticed that the platform did not move entirely smoothly with the Z screw removed. One of the two bearings seems damaged, it does not move smoothly over the axle and tends to jam. Problem found. Thanks again! I'll contact UM support.

Thanks for the extensive response. The under-over extrusion seems logical. #1 - Does seem the least likely - when I (rarely) run into feeder problems it grinds the filament so that it stops extruding. #2 - Temperature does fluctuate a bit but within 1 degree C (so 220-219-220-221-220). I have a little door for the front opening to eliminate big drafts. #3 - I tried this and it does not feel very smooth, but it's more a constant friction than stick-slip. No other Ultimaker 2 around to feel for a difference, but I'll look at it more closely. Only greased the Z screw and oiled the rest with a drop of sewing machine oil. The effect seems worse with larger layer heights. 0.1mm seems to print OK-ish on small objects.

Hi all, Hope you guys can help, I don't get it. There are two recent threads that show similar faults, but neither of those situations are exactly the same as far as I can tell. I have an Ultimaker 2 that has about 900 printing-hours on it. It's on its second nylon spacer and nozzle since about 200 or 300 hours. Over the past few days vertical walls have become very ugly. I've greased everything, cleaned the nozzle, leveled, etc. Different filament does not seem to make a change and I use good quality filament. I have been using this feeder for the past 500 hours without problems: https://www.youmagine.com//designs/alternative-um2-feeder-version-two . PLA, .2mm, 50 mm/s at 220 degrees. There is some slight underextrusion visible on some parts. Dropping to 210 degrees gives more severe underextrusion: Help! Thanks.