In this article you will find how to proceed if you are experiencing underextrusion
Underextrusion is the most common printing issue in 3D printing. It consists of a lack of extruded material in the printed part that will show as missing layers or spongy prints.
What is Underextrusion and why it happens
Underextrusion, as the name states, happens when the hotend extrudes less plastic than desired. This issue affects directly to the quality of the printed part. Making it look rough, incomplete and weaker than usual. There are many factors that can make this happen.
We recommend using BCN3D filaments with our 3D printers. The default BCN3D Cura profiles for BCN3D filaments are tailored by our Lab to deliver the best quality and reliability on your prints, so if you find underextrusion in one of our filaments, it's possible that the filament itself needs to be dried, or there's a problem in the hardware.
There are many ways to fix this issue, as there are many causes, you should check all the options to locate the issue and fix it effectively.
How to fix it
As this issue has many different causes, troubleshooting the issue can be complex. Here's a list of all the causes and ways you can fix this. If one point does not do the trick, go to the next one.
1: BCN3D Cura version
Older BCN3D Cura releases have different profiles that may cause printing issues like underextrusion. BCN3D Cura is constantly updated with new profiles that work better, pay attention to the release of new versions of BCN3D Cura, and make sure to keep it updated.
To know how to download and install Cura, visit this article: BCN3D Cura.
A printer with an old firmware can have some bugs that may cause underextrusion. To upgrade the firmware of the printer, Check out this articles depending on your model:
To avoid Underextrusion, we recommend the default profiles for BCN3D Filaments in Cura, those profiles are specially made to ensure a safe print, ensuring the best print quality. If you are experiencing underextrusion with our materials and using our default profiles, go to the next point.
If you are using custom profiles or filaments from a different brand, note that there are some factors that can also cause underextrusion, such as excessive printing speed, low printing temperatures, or a bad retraction configuration. Here are some tips you can use to prevent this from happening.
Tip: If you use materials that are not from BCN3D, feel free to contact the manufacturer to get a printing profile for your filament, they know their filaments more than anyone else.
Printing Temperature: Normally if you find underextrusion, the first thing to look at is the printing temperature. Most 3D printing filaments show a range of temperatures in the same spool. To find the right temperature , you can print the following test and change the printing temperature until you find the one that has the best quality:
Start from the higher temperature and lower it in 5ºC steps while it's getting printed, write down what temperature goes best with that material.
Printing Speed: If the printing speed is too high, you'll notice that the hotend is not able to extrude enough material on the printed part. Speeds of 50mm/s are generally good for ABS, PLA and PET-G, while other filaments may require slower speeds.
Retraction Settings: Retraction is a feature in which the filament is pushed out of the nozzle a bit to prevent oozing during a travel. If the amount of retractions, retraction distance or the retraction speed are excessive, you might find gaps appearing on the walls of the print or experiencing hotend clogs.
Note: For more information about how to use BCN3D Cura, you can download the user manual here: BCN3D Cura User Manual.
Sometimes, underextrusion will appear even when printing two exact print jobs with the same materials and configurations. Take into account that underextrusion also depends on the filament and room humidity, room temperature, and manufacturing defects.
To prevent other issues with our filaments, check the following tips and tricks articles for each material:
4: Bowden tubes
The bowden and the filament are in constant friction. Occasionally an excess of friction can stop the filament and could cause underextrusion. Check the bowden and if it is bent or has a bad shape, change it for a new one.
If this is the case, contact us or your reseller of choice to get a new bowden tube.
5: Bad cooling
An excess of temperature in the printing head can cause a clog in the hotend, this will cause a gradual underextrusion along with the print until no filament is extruded. Check if the cooler fans are clean and use a vacuum cleaner or a brush to ensure that nothing is blocking the fan. To check if the fans work properly, follow the next articles:
Note: In some cases, room temperature can influence this, especially with PLA. Check that the room temperature is not over 25ºC and there's correct airflow in the room.
A constant underextrusion throughout the piece shows that the issue can be located in the hotend, specifically if you use different materials in the same hotend. If you are using multiple material types, the hotends can clog overtime; you should always clean the hotend with nylon every time you change material types. Check these articles about how to clean the hotends:
If the problem persists, probably the hotend is damaged or clogged severely, try to swap the hotends and print, if the problem moves, you will need to unclog the hotend or swap it out for a new one. The following articles have information about it:
Usually, if the hotend is burnt or damaged, the extruder board has a problem, go to the next section to find more information about this.
Warning! Hardened steel hotends shouldn't be used for non-abrasive materials like PLA, ABS, PET-G, TPU, etc. For non-abrasive, plain materials, it's best to use brass-tipped hotends.
7: Extruder Board
This component controls the hotend temperature and the fans function. If the extruder board doesn't work properly, it can lead to random underextrusion and overheating issues during the print job.
To check that the problem is here, you can swap the extruder boards, if the problem moves to the other printing head, you will need to swap out the extruder board in question for a new one.
For more information about how to swap and change the extruder boards, see the next articles:
8: Extruder motor
If the extruder motor can't push the filament correctly, the result will be underextrusion. Sometimes this is accompanied by a repetitive clicking noise.
To fix or change the extruder motor, check the next guides:
If the problem continues, swap the extruder drivers and check if the problem moves from side. These articles will help you with this:
If you still experience underextrusion issues, get in contact with our support team by filling this form.
Repair didn’t go as planned? Check out our forum community for troubleshooting help.
It's important to keep your printer in good shape to make the most out of it. In this chart you can find a list of the extruder maintenance procedures and how frequently these should be done.
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