Can You Leave Filament in a 3D Printer? What to Do Instead


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A dual color polymaker polyterra roll of filament left on the 3d printer

What should you do with the filament when you’re done with a 3D print? If you aren’t using your machine for a bit, you might wonder, can you leave filament in a 3D printer?

Generally, leaving filament in your 3D printer isn’t harmful to the printer, but it can lead to issues with filament quality over time. 3D printing filament tends to absorb moisture, which can affect the quality of your prints.

 The length of time you leave your filament in the printer depends on the humidity and temperature of the surrounding environment.

To prevent filament quality issues, store your 3D printer filament in a dry, low-humidity environment. Remember, taking care of your filament and your 3D printer will ensure you produce high-quality results without wasting time or filament on failed projects.

Can You Leave Filament in a 3D Printer?

A dual color polymaker polyterra roll of filament left on the 3d printer

Yes, you can leave filament in a 3D printer, but it can cause the quality of the 3D printing filament to degrade as it absorbs airborne moisture.

Filament quality can decline if the environment around the 3D printer is too humid or hot. 3D printing filament is hygroscopic, meaning the filament tends to absorb moisture from the air.

Nylon and PETG filaments are particularly sensitive to humidity, but PLA and ABS also absorb moisture over time.

Although leaving filament inside the extruder for short periods won’t damage your printer, it’s a good idea to remove the filament if you anticipate not using your 3D printer for a while.

To help maintain print quality, keeping your filament in a moisture-proof container when not in use is best. Properly storing your filament prevents degradation and ensures you always get top-quality prints.

If you do find that your filament has absorbed moisture, it’s not lost.

You can dry wet 3D printing filament in a dehydrator, oven, or filament dryer to return it to optimal performance.

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You can often leave the filament in a printer for a day or two before it is negatively affected. But if you’re printing with nylon or PETG, it’s best to remove the filament as soon as you’re done printing.

ABS is one of the least hygroscopic filaments and can stay in a 3D printer for a couple of weeks without compromising the filament’s performance.

Risks of Leaving Filament in a 3D Printer

A 3D printed rocket with print defects from leaving the filament in the 3D printer for too long. The print has zits, blobs, under extrusion, gaps, and stringing

When you leave filament in your 3D printer for extended periods, various factors from the environment might negatively affect the performance and quality of your filament.

Firstly, 3D printing filaments absorb moisture and humidity in the air. The amount of moisture your filament will absorb depends on the type of filament.

PETG and nylon are most susceptible to moisture absorption. But even PLA and ABS can be affected by moisture to some extent.

When a filament absorbs moisture, it can become brittle, reducing its strength and making it more prone to breaking during the 3D printing process.

A 3d printed pikachu with print imperfections like stringing, zits, and blobs caused by wet filament
This model was printed with filament that was left in the printer for more than one month. You can see the stringing, zits, blobs, and gaps caused by printing with wet filament.

Furthermore, when the water in the filament heats up, it can lead to gaps and blobs throughout a print. When the wet filament is heated inside the print head, the water turns to steam and looks to escape through the nozzle.

The steam and brittleness of wet filaments lead to print defects like gaps, holes, zits, and blobs.

If you hear hissing or popping sounds from the print head, it’s a good sign that the filament has absorbed too much moisture.

You can dry wet PLA in a dehumidifier, oven, or filament dryer at 60°C.

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SUNLU Filament Dryer Box
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Additionally, the moisture-laden filament can cause clogging or jammed extruders. When the filament is heated in the extruder, the absorbed moisture becomes steam, causing bubbling and popping sounds. This can lead to uneven extrusion, stringing, and poor layer adhesion in the final print.

How to Remove Filament from a 3D Printer

A hand pressing on the filament release clip on a 3D printer to remove the filament from the extruder

Removing filament from your 3D printer when it’s not in use for an extended period is always a good practice. Properly storing your filament between use prevents the filament from absorbing moisture.

You’ll also need to remove the filament from a 3D printer in case of jammed filament or when you need to change filament types or colors.

Let’s review the steps to remove the filament from your 3D printer.

  1. First, heat up your printer’s extruder to the normal printing temperature to remove the filament material. Setting the nozzle temperature softens the filament enough to gently pull it out without causing damage.
  2. Once the nozzle reaches the desired temperature, carefully apply pressure on the printer’s extrusion or “load” lever. Pressing on the load lever releases the tension on the filament, enabling you to slide it out.
  3. Gently pull the filament out of the extruder, making sure not to yank hard or jerk the filament during the process.

How Long Can You Leave PLA Filament Out?

PLA filament is a popular material choice for 3D printing due to its ease of use and biodegradability. Because PLA can absorb moisture from the air, you might wonder how long you can leave PLA filament out in the open.

You can leave PLA filament in your 3D printer for short periods without any significant damage. In our experience, leaving PLA filament out for a few days to a week without any issues is safe.

Factors like air temperature and humidity affect how long PLA can be left exposed.

If you live in a dry climate, you can leave your PLA filament in the printer longer than in a hot, humid climate.

PLA tends to absorb moisture over time, which can result in poor print quality and even clogged nozzles.

We generally recommend removing PLA filament from your printer and properly storing it in a cool, dry container if you won’t need it for more than two days.

To ensure the best possible 3D printing experience, you can invest in filament storage solutions like vacuum-sealed bags, storage containers with desiccant packs, or even dedicated filament dry boxes. These storage solutions will help extend the life of your PLA filament and provide consistent print results.

Our Pick
SUNLU Filament Dryer Box
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Marcello De Lio
Marcello De Lio

Marcello co-founded 3D Print Mentor to share his love of 3D printing. Marcello used to own an online 3D printing company, where he sold unique designs and customized novelty gifts. After closing the business, Marcello’s new passion is 3D printing replica movie props and cosplay items.

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