Strange outer skin print quality on Ender 3

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1

Does anybody have an idea what causes the strange outer wall skin texture? I don't know why this happens; the inner wall looks fine, but the outer wall looks distorted.

Also it's strange that the distortion only happens on the left side for about 2 cm on all prints.

Disabling retraction had no effect. Reducing the printing speed neither improved it.

Edit: I'm printing at 0.16mm layer height with 98% initial flow rate and 94%. No support. Standard PLA with the standard nozzle at 190°C. I am using Cura for slicing if it matters.
Printing speed is at 40mm/s for the outer wall and 80mm/s for the inner one. I already tried to decrease the outer wall speed to 20mm/s without any luck. Except for one other print, I never had an issue with those settings.
I just finished a print with 100% flow rate to exclude its the flow rate. With 100% only the front improved at all. Front side Back side

Julian

Posted 2019-04-05T18:09:44.843

Reputation: 111

2There is no stringing, your print suffers from under-extrusion. Please add some relevant settings as speed, temperature, extruder type, filament type, etc. This is virtually an impossible task to answer without such information. – 0scar – 2019-04-05T22:26:39.397

1Could be speed on outer layer too fast. Could be hot tip too cold. – Perry Webb – 2019-04-06T19:21:09.810

I'm agree with Perry, I had the same problems when I started to print. also the filament quality was a headache, but I didn't´notice until I changed my supplier. – Fernando Baltazar – 2019-04-10T17:49:39.823

Have you tried using one of the default standard profiles in Cura? I'm just wondering if there is some weird setting that has been changed by mistake. It seems unlikely that there is anything wrong with the printer or filament if the inner walls are ok. – BG100 – 2019-04-15T08:43:44.573

Answers

1

My best guess is you have an under extrusion issue, possibly related to retraction: the issue is exacerbated on parts where the printer has to hop over a gap.

I would try running, in the order:

  1. print a flow rate test, to ensure the amount of filament exiting the nozzle matches with your configuration
  2. print a retraction test, to ensure you are not suffering from some bowden tube issues like bad coupling
  3. check for any clog in the hot end, those can require a bigger pressure to build up before the filament start flowing again
  4. print a temperature tower, to find out if 190° is the right temperature (seems a bit low to me)

With regards to point 2, the Ender 3 is somewhat renown for having poor quality couplers: watch the bowden tube couplers when printing and try to verify the tube is not moving back and forth when hopping over empty spaces...

Roberto Lo Giacco

Posted 2019-04-05T18:09:44.843

Reputation: 307

This is an under extrusion due missing feed extrusion vs filament temperature. There are many topics explaining this issue. – Fernando Baltazar – 2019-04-10T06:04:37.857

Why has this answer been down voted? – Roberto Lo Giacco – 2019-04-10T10:34:39.177