If you've been 3D printing for more than a few hours, you've seen it: thin, wispy strands of plastic stretching between parts of your print like spiderwebs. That's stringing — and it's one of the most common quality issues in FDM printing.

In this guide, I'll walk through:

What causes stringing (and it's not always what you think)

How to fix it manually (temperature, retraction, travel settings)

How to automatically detect it using computer vision

Let's start with the why, then the how, then the tools.

What Actually Causes Stringing?

Stringing happens when molten plastic oozes from the nozzle during travel moves — when the nozzle moves from one part of the print to another without extruding.

Without stringing: ╔══════╗ ╔══════╗ ║ ║ ║ ║ ╚══════╝ ╚══════╝

With stringing: ╔══════╗~~~~~╔══════╗ ║ ║ ║ ║ ╚══════╝ ╚══════╝ (thin wisps between parts)

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Three factors determine whether stringing occurs:

Factor How it causes stringing

Temperature too high More…