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String on first layer MK3S+  

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PeteM
(@petem)
Member
String on first layer MK3S+

Hi

I'm having a new issue where a string pulls from the initial wipe to the first layer on every print, regardless of the model. The print will complete, but the bottom layer has some defects due to the string.

  • All hardware original, except Nylock mod
  • Prusa PETG (dried)
  • Textured plate
  • Default settings for Prusa PETG in Prusa Slicer, except first layer speed is 10 mm/s
  • Nylock mod implemented - bed is level and has a .03mm variance
  • Z is calibrated
  • Prusa recommended Precision Method Cube gcode - wall width prints perfectly
  • Performed cold pull clean, nothing unusual came out
  • Adjusted extruder gear tension tighter and looser
  • Belts tensioned - X should be spot on, Y may be very slightly looser than optimal
  • Re-ran setup wizard
  • PID calibrated
  • Bed cleaned

Any ideas or advice appreciated.

Posted : 20/11/2021 8:19 am
FoxRun3D
(@foxrun3d)
Famed Member
RE: String on first layer MK3S+

I see this frequently, especially with PETG. Make sure nozzle and print head are squeaky clean. You may also want to play with retraction values. 

Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...

Posted : 20/11/2021 2:18 pm
Dan Rogers
(@dan-rogers)
Noble Member
Catch it as it happens and move on

I keep a set of silicone squeegies (just little squares of silicone) by my print bed.  Since you DO watch every print start you have the opportunity to catch that little string happening and just pull it away from the nozzle as the printer starts on the skirt.  It rarely goes past the skirt so it seems an exaggeration that your first layers are getting ruined ... but maybe your nozzle is super crudded up and needs a cleaning too.

I know that little string well.   It happens with petg.  It also happens even more with flex.  The realy quandry is why is it stretching past your skirt ... you ARE printing the skirt yes?

Posted : 23/11/2021 11:47 am
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