Stringing

All troubleshooting pages are a work in progress.

Identifying Stringing

Stringing refers to the little strands of filament that connect different islands of your print. Stringing is also related to the little filament deposits that you might see where travel moves are taking place. These deposits are usually a less severe version of stringing, and are a step in the right direction from what is typically identified as stringing.

Causes

Even when your printer isn’t actively extruding (pushing) filament, molten plastic will still slowly leak out of your HotEnd. This leakage can cause several different quality imperfections, one of which is stringing.

Stringing is caused by filament oozing out of the nozzle of your HotEnd while it isn’t actively printing. This typically happens during travel moves or during the transition between layers. Occasionally stringing can happen during Z-hops. To reduce stringing, you need to cut down on the amount of filament oozing out of your HotEnd.

Solutions

Temperature

Lower your temperature

Retraction

Increase retraction distance and speed

Z-Hop Tuning

Decrease Z-Hop distance

Travel Speed

Increase Travel Speed

Temperature

Filament ooze is usually caused by filament being overheated, which makes it less viscous. This depends a lot on your HotEnd, accuracy of your temperature sensor, and the filament type that you’re using. If you’re printing too hot, filament will ooze more, leading to more stringing

Experimenting with one of the numerous temperature calibration tests will help you see what printing temperature is right for you. Typically lowering your printing temperature by 5-10° can be a good first step to test.

  • Some materials have very stringent temperature guidelines for printing. For example, PVA should not be printed above it’s recommended temperature range, as it is liable to burn and clog your HotEnd.

  • Remember to be mindful of your HotEnd’s maximum temperature!

  • Trying to print with low temperatures can increase the risk of grinding your filament, due to extra back-pressure in your HotEnd.

Retraction

Retraction is the most common defence against stringing. Removing filament from the HotEnd while traveling helps reduce ooze, and in turn eliminates stringing effectively. Tuning your retraction settings for your HotEnd and printing material can take some time but will lead to much higher quality prints.

While conventional wisdom is to always increase your retraction distance to remove stringing, this isn’t always the best solution. Depending on your HotEnd, there is usually a maximum amount of retraction that is useful, and going above that value can cause clogging (filament will be retracted into the cold part of your HotEnd, expand, and stick to the walls).

It is a good idea to experiment with different amounts of retraction. Usually, printing several retraction tests can help you find a retraction distance that will work for your HotEnd and filament. Don’t forget to try out different retraction speeds as well, as faster retractions can help eliminate ooze too.

Flexible materials are frequently printed without retraction to help reduce buckling.

Z-Hop Tuning

If your printer’s Z-axis moves very slowly, having a large amount of Z-Hop can leave a lot of time where your extruder isn’t pushing filament. During that time, filament could ooze and so you might notice extra stringing.

If possible, increase your Z-axis movement speed, but make sure that you don’t accidentally lower your print quality by moving too fast. If it isn’t possible to speed up your Z-axis, you can lower the amount of Z-hopping either by reducing the Z-hop height, or by limiting Z-hops to only happen before to larger travel moves.

Travel Speed

If your travel speed is very slow, you may be giving your filament a lot of time to ooze out of your nozzle. Try testing faster travel speeds to see what your printer can handle.