I have a Wanhao Duplicator i3.
I have done many excellent prints with this printer, and have first hand experience that it can do a pretty much flawless print.
But... Recently, I am experiencing weird results. My "flow" seems uneven. When laying down the first layer of the raft, I can see it looks like it "beads" in some places. Thin lines with little "beads" here and there (which seem to be in a constant pattern) i.e. -------()-----()-----()------()------ etc.
I initially thought, wet filament... But drying the filament had no noticeable effect. Further more, all my prints seem to be horribly laminated at a certain "height" of the print. This is really strange as it will print perfectly and only at a certain height, mess up about 5mm of layers (height wise), and then print great again. This seems to be a constant now.
I dont understand how/why this could happen, as the whole z-axis is on a linear spiral shaft. Unless there is a gcode issue somewhere that I am not aware off. I am using CURA as my slicer and I feel that even if there was an isnturuction hidden somewhere at a certain height, it would possibly effect a single layer, and not 5mm worth of layers.
I have tried:
Different filament Pushing flow % to 105 and 110% respectively Cleaned extruder gears and print head Oiled z-axis shafts
What baffles me, is the weird delamination (or rather lack of lamination) at a certain height. I have not measured this height exactly, but from guestimating, it looks like roughly the same height on every print where the issue is visible (about 3/4 up in the attached image). My support structures are also VERY messy, whilst they were very precise and perfect previously.