I'd like some advice regarding defects on my print : enter image description here

enter image description here

Here some details :

  • Printer CR-10 S, nozzle 0.4
  • Material PLA
  • Bed 60, Hotend 215, 50 mm/s speed
  • SLiced with cura 4.1, 5 walls (i can provide more detail of the profile if needed)
  • Layer height 0.1
  • modeled on fusion 360
  • The surface where the defect sits is actually tilted 45 degres

Thanks !


There are many possible causes for printing defects, but the easiest one to eliminate is dirt. Always use a filament cleaner to prevent dirt from entering the extruder. There are plenty of designs available on Thingiverse. Always keep your nozzle clean. After pre-heating mine, I clean it (carefully) with a folded paper kitchen towel. It may also be worthwhile doing a "cold pull", if you suspect that you have dirt in your nozzle. Finally, you should check that filament is not leaking out between the nozzle and the heater block.

  • 1
    $\begingroup$ It's true that the filament littly scrub against soft wood, maybe some bit got dragged along, i will add a filament cleaner, it can't hurt anyway ! Thanks for your help $\endgroup$
    – Benoit
    Jun 15 '19 at 15:26

This could be a problem with the filament rather than the printer.

If the filament contains air bubbles, they will heat and pressurize. The additional pressure can increase the flow rate for a moment as the molten material in front of the bubble is expelled. The flow rate decreases after the bubble pops through the nozzle because the now-empty space needs to be filled by the extruder pressing new filament into the melt zone.

If this is happening, you might hear little pops.

Alternatively, the filament may have absorbed water, which can convert to steam and explode out the nozzle like a bubble would.

Drying filament isn't hard. I use my household oven at it's lowest temperature, which is typically about 160 degrees Farenheit. This is high enough to slightly soften PLA, so don't go any high than you must. Bake the filament for an hour, let it cool before handling it and try again.

The filament may not be quite as round after baking, but the cross-sectional area shouldn't change.

If the problem is from bubbles, there isn't anything you can do to fix it. If it is from water, you can fix the filament. I'd suggest baking the filament and seeing if anything changes.

  • $\begingroup$ My roll is almost done, if the next one have the same issue i'll try baking the filament (have to be discrete, not quite sur the wife apreciate filament in the oven :) thanks ! $\endgroup$
    – Benoit
    Jun 15 '19 at 15:32
  • $\begingroup$ I'm sure you can make a good explanation for the plastic in the oven. By now she must realize that you aren't an evil genius. Don't do it on the grill. Controlling the low temperature may be much harder. $\endgroup$
    – cmm
    Jun 17 '19 at 13:21

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