Broken Filament on extraction from extruder

I disagree that moisture is the root cause, as poor tensile strength is not a typical symptom of moisture absorption. However, to eliminate moisture as a factor, I used a SUNLU dryer to dry the filament for six hours at 55°C. After the drying cycle, there was no measurable weight loss when checked with a digital scale. I then re-ran the print to verify the results.

As expected, the outcome remained the same. I would appreciate further assistance in diagnosing the issue before approaching Bambu to report a potential defective batch.

Based on other research I’ve done I may have additional causes.

  • Increased Brittleness:
  • Some users have noted that Silk PLA filaments exhibit increased brittleness, leading to breakage during retraction cycles.​
  • No fix
  • Heat Creep:
  • There are instances where inadequate heat dissipation in the extruder leads to filament softening above the hotend, causing deformation and breakage during retraction. ​forum.bambulab.com
  • Need a suggested fix
  • Retraction Settings:
  • Excessive retraction distances and speeds can contribute to filament grinding and breakage, especially with Silk PLA. Adjusting retraction settings has been suggested as a potential solution. ​forum.lulzbot.com
  • Need a suggested fix.