The common advice is incomplete
If you have been 3D printing for more than a month, you have probably been told to increase retraction when you see stringing. It is the default answer in forums, Facebook groups and YouTube comments.
The problem is not that retraction does nothing. The problem is that the advice ignores why stringing happens and how retraction actually works.
Stringing is stored pressure plus opportunity
Stringing happens when material continues to leave the nozzle during a travel move. The two most common reasons are stored nozzle pressure and a material state that makes the plastic too willing to ooze: too hot, too wet, or too slow to cool.
More distance can create more problems
Too much retraction can pull softened filament into cooler zones of the hotend, increase the risk of clogs, grind the filament, create inconsistent priming after travel moves and make prints slower without actually solving the cause.
What to check before increasing retraction
Dry the filament, verify printing temperature, calibrate Pressure Advance, check travel speed and avoid crossing open areas when possible. Then tune retraction with a tower using the smallest value that produces a clean result.
Direct Drive vs Bowden
Direct Drive needs small retractions because the filament path is short and controlled. Bowden needs larger values because the long PTFE path acts like a spring. Do not use Bowden values on a Direct Drive toolhead.
CN3D takeaway
If retraction is already in a sane range and stringing remains, stop increasing the number. Use a troubleshooting flow and find the real cause: wet filament, temperature, pressure advance, travel behavior or hotend heat management.
Use this in the CN3D workflow
This article is part of the bigger calibration and troubleshooting system. Read the concept, then apply it with the calculator or diagnostic flow.