Try another filament spool - the voids are symptomatic of filament that has absorbed moisture from the air. You extruder drive gear could also be a problem here - it may have bits of plastic embedded in the teeth which causes the filament to flow inconsistently. Check and clean with the small wire brush. The drive gear idler is also a problem spot. It wears and gets sloppy on the shaft. I actually installed ball bearings into mine.
I live in Louisiana. The biggest problem I run into is humidity. I place my spools in a ziplock bag with a little bit a desiccants that I bought from Lowes. This is what I suggest to do.
I have a big problem with nylon. I put it in a bag for 24 hours and the next day it is printing like a champ. After a week or so in the bag you will see a pool of water that it is collecting. Tons of water is stored in the plastic.
what size ball bearings did you use in the idler? I have been packing mine full of grease lately which seems to help, but switching to a bearing would be the best thing to do.
I’ve put my filament in the oven for about 2 hours to dry it out. That had no effect on the print quality. Did the same (a bit longer) for another spool, also without any effect. Although I have to agree with all advice here that the filament really isn’t sticking properly.
Maybe the temperature of the nozzle isn’t correct?
There was one setting that had a big effect on the print quality. Turning infill before perimeters off. To my surprise though because before turning this setting on actually improved all my prints dramatically.
I added a pic of the results so far (also showing a whole new problem), sorry for the poor quality (new phone broke).
Left is what it printed like up to 3 weeks ago.
The middle one 3 weeks later without making any changes (besides cleaning the print nozzle and leveling the bed).
On the right is the current result.
Besides the top part getting messed up (does that every time, but only with this model, no clue yet what causes it) it looks pretty similar to the original old print. The print is still a little bit zigzagging in the Z axis, but definitely acceptable. The problem I have is the seems, they are pretty wide and go inwards while the original goes out. With this white filament the shading makes them very visible.
Is there any way to tweak this and get them seems tighter and maybe oozing(?) out a little bit.
Thanks for all the advice so far, I still have to look into some of the more hardware related solutions, because I have no idea where I can even find most of the parts that are mentioned
Very unusual problem! Have you inspected your extruder gear? Perhaps there is an obstruction or noticeable wear. Also I have found when changing filament that I’ve had to increase or decrease the temperature as not all filaments are the same quality.
Apart from that I would suggest reducing the distance between your extruder nozzle and heated bed just a tiny bit. Good luck!