I just changed my nozzle on my Anet A8 after it was fully used up. When I started printing with my new 0.4 mm nozzle (same as before) my extrusion was VERY bad and inconsistent, even so bad I couldn't continue printing because it would pull the first layer off.

If I compare it to my extrusion before the nozzle switch, it is really bad, even though I tightened everything as before. I am quite sure it doesn't have to do with adhesion to the heated bed since I use tape with PVA glue.

Any advice on how to remove this under extrusion so I can continue printing?

All the specs:

  • 25 mm/s first layer print speed
  • 200 °C nozzle
  • 60 °C bed
  • PLA filament;
  • 0.4 mm nozzle size

Let me know if there is anything else you need to know.

  • 1
    $\begingroup$ I usually buy them in packs of 5, do you have another to test? The cheap ones sometimes are not 0.4 mm or are very rough on the inside. $\endgroup$
    – 0scar
    May 2, 2018 at 19:19
  • $\begingroup$ What kind of test you mean? I have gotten about 10 of these prints, all inconstant and not usable to continue printing. $\endgroup$
    – HugoG
    May 2, 2018 at 19:30
  • 1
    $\begingroup$ another nozzle to test; screw another on? $\endgroup$
    – 0scar
    May 2, 2018 at 19:31
  • $\begingroup$ Nope, I don't have any other nozzle to test at the moment. I did order some, but they won't be here until at least one month. $\endgroup$
    – HugoG
    May 2, 2018 at 19:41
  • $\begingroup$ Did you readjust the bed level? $\endgroup$
    – 0scar
    May 2, 2018 at 19:58

3 Answers 3


To be sure it's from your nozzle / extrusion mecanism, you could check calibration by extruding (in the air) 100mm of filament, and check how much it really uses. If it uses 100mm (or so), then the problem comes from any other parts (bed, filament feeding...).

If this is really an extrusion problem, first you can check again your extrusion step motor gear. If it's ok, then you could put back your old nozzle to ensure the new one is the problem... If all is ok with the old one, then yous should have something in your new one, or it's not a .4mm ?


Your good extrusion look also a little bad , and the bad extrusion looks like a big feeding problem. for this you need:

Feeding.- try to tight the presure of the feeder thread, the one that press the filament on the extruder.

Bed Adhesion.- Use between 32° and 38°C if you are using masking tape, on higher temperatures the masking tape becomes to peel off if any border of the printing part is close to the edge of the tape.

Sand the masking tape surface and clean it to be free of dust (eliminate shiny surface) with this is enough to get a good adhesion; I recommend TUK and 3D brands, they are sticky. If you need more adhesion you can spray a little hair spray, just one pass.

Clogged Nozzle.- you need to clean it, on your kitchen stove heat the nozzle until melt the filament, then use some cooper wire (some phone wiring has it) to remove residues inside the nozzle. If posible you can buy a drill bit with 0.4mm diameter to ensure a complete cleaning.

  • $\begingroup$ With the 'feeder thread', do you mean the throat that guides the filament to the heat block? If so, I already tightened it the best I can when I reassembled it. $\endgroup$
    – HugoG
    May 3, 2018 at 8:00
  • $\begingroup$ I will try to lower the bed temperature and sand it, I hope it helps. For the nozzle, I have tried a similar method with my old nozzle, but I would be very surprised if my new nozzle is already clogged. I might buy some cleaning filament just to try if it helps, because It was quite a hassle to remove the nozzle etc. $\endgroup$
    – HugoG
    May 3, 2018 at 8:07
  • $\begingroup$ I would be very cautious with a drill bit, especially if your nozzle is the usual bronze (soft). A 0.4mm bit will easily grind the opening wider than you want. $\endgroup$ May 3, 2018 at 14:38
  • $\begingroup$ @HugoG No, the "feeder thread" is the one that is close to the motor which press the spring to compress or release the filament. I had the same problem due the spring has a low compression. $\endgroup$ May 4, 2018 at 1:49

In the nozzle assembled properly? As I assumed that there were no other changes during the nozzle exchange process, then there is a risk of a gap inside throat and nozzle that just builds up and blocks the extrusion.

Please see this answer for an assembly hints.

  • 1
    $\begingroup$ No, it is assebled properly, since if I push the filament through myself it goes through smoothly and the diameter is 0.42mm, so all is good in that departement. $\endgroup$
    – HugoG
    May 3, 2018 at 10:00

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