Updated 4 weeks ago ​by Tomáš Chvalina

You can recognize under-extrusion when there is material missing in your print’s layers. Printed objects with under-extruded layers tend to be fragile and will usually break apart in the under-extruded layer area. When the under-extrusion is as severe as shown in the picture, it’s usually caused by a hardware problem. Software adjustments mostly work only as a hotfix and they might cause further problems in the future. However, if you have been tweaking the slicing settings yourself, then we would highly suggest doublechecking them because that might be the actual cause of the problem.


  1. Loose extruder gears – Make sure that your printer’s extruder gears are properly tightened. They must be tight enough to grab the filament and push it into the extruder, but do not unnecessarily overtighten them. 
  2. Dirty extruder gears – Always check that your extruder gears are clear of any leftover plastic. The extruder gears can also accumulate a layer of rust over time. Use lithium-based grease to clean them, but apply it only to the toothed part as seen in the right photo below! If you apply it to the whole gear, it will be unable to grab filament properly!
  3. Bad filament – If the filament’s diameter is larger than the standard tolerance, it might be the source of the problem. You can use a caliper to check the diameter (+/- 0,05 mm is acceptable, but not perfect). Also, try using a different filament in case you can’t properly inspect the current one. See if the problem persists with a different spool.
  4. Extrusion multiplier – One of the possible solutions is to tune the extrusion multiplier. However, before you do that, first make sure that hardware is not the cause of the issue. Increasing the multiplier will increase the flow of the filament into the extruder, decreasing will have the opposite effect.

This should cover the most common problems related to under-extrusion. But what about the over-extrusion? Frankly speaking, it’s quite rare. Over-extrusion happens almost exclusively when you used incorrect printing settings for extrusion width, perimeters etc. A newer version of our Slic3r PE won’t allow it to happen. We recommend to always use the latest version of our Slic3r. 

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