Should You Always Remove Filament After Printing?

Storing filament can be a particular and delicate process. However, with so many claims about when you should remove filament after printing and how to keep it, it can seem like people are being a little too extreme in their advice. So, can you leave filament in a printer, and if so, are there any consequences? 

You should always remove filament after printing to protect it from moisture and dust. Since keeping a room free of moisture, dust, and temperature fluctuations is hard, it’s best to unload the filament after each print job.

In this article, I’ll tell you all about when it is and isn’t a good idea to leave your filament in your printer after a print job. I’ll also offer tips for storing your filament and explain why proper storage is critical. 

How Long Can You Leave Filament in the Extruder?

Some people aren’t too worried about sealing up their filament, which you will find out pretty quickly on 3D printing forums. It can be a hassle to unload and reload your filament before and after every print. 

However, emptying post-print is always the best practice regarding filament. That’s because many filaments actively absorb moisture. In addition, leaving the filament exposed to dust, dirt, and anything else you have floating around in the air might affect the quality of your prints later. 

So, regardless of how hygroscopic material is or isn’t, it shouldn’t stay in an extruder any longer than a day if you’re not actively printing with it.

However, ideally, you should remove it and place it in a sealed container after every use. Packing it up ensures that even the most hygroscopic filament stays in good shape for its entire lifespan.

Why Shouldn’t You Leave Filament in the Extruder?

Some filaments are highly convenient because of their waterproof qualities, but others aren’t so simple. 

Hygroscopic filaments like nylon and PLA are sensitive to moisture in the air. These plastics quickly absorb water if left unsealed. Once this happens, the filament will swell, drastically affecting print quality. 

Here is what will happen if you attempt to print an object with a moist, swollen filament:

• Prints will become brittle and fragile, even if the filament is typically sturdy. 
• Moisture leads to trapped air bubbles inside the filament, causing hissing and bubbling sounds when printing. 
• Wet filament means poor layer adhesion, meaning that the layers will struggle to bind to one another, resulting in a print with gaps and warping. 
• It can become stringy when heated, resulting in unstable and low-quality 3D items.

The following video demonstrates the effects of moisture on a filament and how it affects the final print compared to how it should look.

How To Tell if FIlament Is Wet

Once your filament shows signs of moisture damage, it may already be too late to save it. Some signs that your filament has become damaged due to moisture absorption and humidity are:

• Filament hissing, popping and bubbling out the nozzle. 
• Stringy prints. 
• Prominent layers and poor layer adhesion. 
• Warping on the print bed. 
• Brittle objects that break easily. 
• A blocked nozzle. 
• Your printer suddenly needs to be set at a higher temperature to extrude the filament correctly. 
• Depending on the type, the wet filament can also produce an abnormally pungent odor. 

Unfortunately, these symptoms only show themselves after you’ve already begun printing. Thankfully, the signs are loud and clear. If your printer or filament is exhibiting any of these, it’s best to try a different filament and see the results. 

If the issues persist, it could indicate a different underlying problem, like incorrect heat or layer settings. 

How To Store Filament To Keep It Dry

Storing filament is straightforward, especially now that you know a filament’s worst enemy is moisture. 

1. Find an airtight bag or container. This container could be a plastic ziplock bag, a vacuum-sealed bag, or any secure household container that can seal. 
2. Keep the container sealed. This step seems obvious, but it’s vital not to allow too much air or moisture to penetrate the container. Seal it after removing the filament and immediately after returning it. 
3. Store in a cool, dry place. Keep the bag or container away from any water sources or direct sunlight. Many filaments are also sensitive to UV rays. 
4. Keep multiple containers. Don’t keep every filament in one bag or container, mainly if you use one more frequently than others. Compartmentalizing reduces the chances that some of your filaments will make all the others wetter. 

Filament Drying Methods

If these steps fail or the damage is done, all is not lost. It’s possible to dry filament without fancy equipment. Any oven will do. 

Every filament requires a particular heating temperature. Setting your oven any higher or lower won’t produce a good result. 

Another more expensive but potentially more effective drying method is a dedicated filament dryer. These dryers are convenient for filaments that release toxic fumes, known as VOCs.  

Filament dryers include heaters and fans to extract moisture. These settings are adjustable, so they actively dry out your filament and make great storage containers. 

Try the SUNLU Filament Dryer Box (available on Amazon.com) out for size. The user-friendly design lets you control how you store your filament. It also accommodates 20 different kinds of filaments for a dynamic experience. 

Can Moisture Damage Your 3D Printer?

Moisture is a massive threat to printing because it damages filament. However, it can also lead to severe printer damage. 

Moisture can damage your printer if your filament is swollen. Filament expands as it absorbs water, which can cause jamming and clogging. If a nozzle clogs, it delays printing. Still, a severe blockage can cause permanent damage, requiring you to buy a new nozzle. 

Extreme amounts of moisture that don’t come from wet filament are a much more significant threat to your printer. If any electrical part of the printer gets wet, it could deal irreparable damage to the entire system. 

That is why it’s crucial to keep 3D printers and filaments as far away from water sources and moisture as possible. When in doubt, it’s better to be safe than sorry. 

Assume that any moisture will degrade the print quality and overall lifespan of the prints and printer. 

Conclusion

Keeping filament inside the extruder is acceptable if you’re printing every day. However, this poses a massive risk to your filament, especially if the filament is hygroscopic. 

So, removing the filament from your 3D printer and storing it in a sealed container after printing is always best.