One of the issues I’ve had, particularly with PETG, has been plastic accumulating on the nozzle to the point where there is enough for it to come off the hotend and deposit itself on the part(s) being printed. The layer adhesion is so strong with PETG, these blobs attach themselves firmly enough to the part that the hotend carriage can be knocked off course when it tries to travel or print through the path where the blob has been deposited.
The results can range from something as innocuous as an ugly blob on the interior of the part between the infill where you’ll never see it (if you’re super lucky) to massive layer shifting that completely wrecks the print.
The first fix for this is to calibrate your extruder. If you haven’t already, checkout Triffid Hunter’s fantastic guide before you print anything else. If you’re over-extruding, this blobbing issue will be exacerbated, so calibrate it… now. I’ll wait.
Even with a fairly well calibrated extruder, you may still have this issue, especially when printing at 100% infill. To further combat this, before each print I bring the hotend to temperature and use a brass brush to clean the nozzle and hotend, removing any residual plastic. This definitely helps on shorter prints, but on longer prints enough plastic can still build up to cause issues.
Now what? Enter E3D’s silicone sock for your E3D-v6 hotend. These little gems prevent the plastic from accumulating anywhere on the hotend. No more cleaning the hotend before each print. No more nasty blobs being deposited on your print. Newer E3D hotend kits come with the silicone socks now, but if yours didn’t, I highly recommend picking up some.
If you’ve tried them, let me know what you think in the comments.