General filament troubleshooting

Filament is often overlooked as a possible problem when troubleshooting prints. Many times, frustrating and intermittent problems can be traced to the storage, handling and settings for filament. A few things to consider:

  • Batches of filament can vary from manufacturers. This is a common problem with the low-cost no-name or house-brand filaments. (Hint: If somebody doesn’t have a filament production line, it’s unlikely that named filament is anything special.)

  • The diameter of lower-cost filaments often varies significantly even within a single spool. This can result in small variations in extrusion between layers, causing irregular flat surfaces. Inexpensive brands are often found to vary by as much as 0.7mm. Even some of the better known filament manufacturers specify variations of 0.3-0.5mm. Prusa has done a lot to publicize this issue with the introduction of their Prusament line advertising 0.2mm or less deviation, and other equivalent products are also available.

  • Filament can absorb moisture or be affected by relative humidity. PLA is relatively immune to this problem, but can be affected in the right conditions. This can result in uneven extrusion, bubbling and steaming during printing, and poor inter-layer adhesion. PETG, nylons and others require measures to prevent absorption of significant moisture even with short exposure.

  • Different filament types and even the same type of filament from different manufacturers can print with significantly different consistencies. This is particularly true when printing with filaments with fillers such as wood, sparkles or carbon fibre added. PrusaSlicer provides a powerful feature for dealing with these variations with the Maximum volumetric speed setting that can be used to provide a speed over-ride for each filament without making wholesale printer setting changes.

When all else fails, don’t forget to try swapping for another spool of filament.

Contact and feedback

You can find me on the Prusa support forums or Reddit where I lurk in many of the 3D printing-related subreddits. I occasionally drop into the Official Prusa 3D discord server where I can be reached as bobstro (bobstro#9830). You can email me directly at

Last edited on Apr 04, 2021. Last build on Apr 03, 2021.