Constantly and Quickly Surging Fans
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Constantly and Quickly Surging Fans  

Constantly and Quickly Surging Fans

Hi, all! I'm hoping someone can help me out here, or at least confirm that what I've found is a legit bug with Prusa Slicer?

Recently, I've been having trouble with my fans surging from 20% to 100% repeatedly at a very high frequency (8900 speed changes within a basic 90 minute print, averages to 1.6 speed changes _per second_). It seems like might be somehow related to dynamic overhangs, but even dynamic print speeds has no effect (on the fan bug). Disabling dynamic fan speeds, the gcode improves very slightly, but the problem persists.

Below is an image of the part I'm printing (the smaller part has a 45* overhang, but (pretty sure) the fan problem persists when printing layers above that, too)

Also a screenshot of my overhang-related settings and a snippet of resultant g-code.

The very last image is the "improved" gcode after disabling dynamic fan speeds, but you can see the pulsing/surging is still present.

Any info or suggestions you might have are appreciated, and please let me know if I can provide any more info about my setup!

Part Image

Print Settings

Fan Settings

GCode Dynamic ON

GCode Dynamic OFF

This topic was modified 3 months ago by jackmanbob
Posted : 02/12/2023 1:27 am