Inconsistent Layer Issues
I was having some issues with printing, most noticeably in this picture:
The layers are very noticeable and sometimes have gaps, and the overhangs don't print very well (although the former is more of an issue). I just calibrated my E-steps so I don't think that is the issue. It was doing the same thing before I upgraded anything (i.e., I had issues on stock hardware).
My printer is an Ender 3 with the metal extruder upgrade (which replaces the plastic parts as seen here), an E3D v6, printed fan duct (Bullseye), glass bed, BLTouch, and vanilla Marlin. Pictures of it are also in the below album. The printed upgrades were printed on a Prusa MK3S and don't have the same issue.
I am using Hatchbox 1.75 mm gray PLA, printed at 215 °C with my bed at 60 °C. I am using Ultimaker Cura 4.1 but was also having the problems on an older version of Ultimaker Cura (maybe 3.6, but I can't remember which it was). The problems also existed with some Hatchbox 1.75 mm black PLA but I used the same roll on my Prusa MK3S without any issues, so I'm not sure if filament could be the cause (although it is a different printer so it's still a possibility).
I have tried at different printing speeds and the problem still persists.
I also recently tried varying the temperature during printing (first up to 222 °C then down to 200 °C) with no noticeable difference.
Extra pictures here.
Model is part of Printable Scenery's sorcerer tower.
This typically happens when the belts are not tight. Note that a Prusa printer is of better quality than an Ender.
Yes, it is a great printer. I figured I would include that to try to rule out non machine issues.
The main issue here (the gaps between layers) was solved by reducing combing.
Combing was enabled without a limit on the range so a max combing distance of 10 mm was introduced. This prevented too much filament from oozing out during travels.
The oozing filament was causing nothing to come out of the nozzle at the beginning of an extrusion, thus creating the gaps that were consistent in location.
Interesting. Could you see oozing/stringing happening inside the infill area? Your experience could be a useful data point for boosting this Cura issue I have open: https://github.com/Ultimaker/CuraEngine/issues/1084
Also, it might be interesting to retry this if you ever upgrade your Ender 3 to later Marlin with the Linear Advance feature. In theory it should greatly reduce the amount of oozing that can happen while combing over unprinted area (space between infill lines), and might be sufficient to stop it without limiting combing.
Good suggestion, I'll take a look into that feature if I have time. I'll try to add details later when I'm with the printer. As I remember, the oozing/stringing was not apparent during printing (I just stated that because I assume that was how the problem occurred), but adjusting the combing clearly removed the artifacts (I ran everything the same except the combing changed). The infill in both cases looked identical to me.