Can You Leave Loaded Filament in 3D Printer?

by Mike Brooks | Last Updated: April 10, 2022

Yes, you can leave filament in a 3D printer! Most 3D printing enthusiasts tend to leave commodity filaments in the extruder between 3D printing sessions.

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Leaving filaments in a well-maintained and operated 3D printer may not be harmful to the printer. However, if left for a prolonged period, filaments get exposed to less optimal conditions.

People least expect plastic materials to absorb moisture, but the hygroscopic thermoplastic 3D printing materials absorb moisture. The hygroscopic nature of filament materials means they absorb moisture directly from the air if left exposed.

Moisture degrades and weakens the filaments, something that impacts negatively on print quality.

Is It Safe to Leave 3D Printer Unattended?

It may not be safe to leave the 3D printer unattended while the printing process goes on full throttle. Many people tend to leave the 3D printer unattended while printing because the process may take longer. Sometimes it takes one or two days, and people tend to turn their attention to other pressing issues instead.

Leaving 3D printers unattended for a prolonged time is risky and unsafe behavior. 3D printers constitute numerous complex elements that make them dangerous compared to other household appliances that you may leave unattended as they operate.

Some of these elements include a high-temperature extruder nozzle, heated beds, motors, and fans. Therefore, many issues can occur when the printer is left unattended.

The electronic fire remains the primary failure that occurs with a 3D printer. It happens when electrical currents and heat build up above the acceptable level in the wiring system.

Safety Measures to Put in Place for Unattended 3D Printing

Knowledge about the risk involved in leaving your 3D printer unattended notwithstanding, you may still find that you occasionally indulge in this practice.

The question that needs answers is what safety measures you need to put in place should you decide to leave your printer printing unattended at home.

Ensure your machine has an auto-shut function to caution it from excessive heat during printing.

Deploy a fire/smoke detection shut-off switch that will help cut off power. The detector can sense smoke or fire around the printing space.

Always isolate your 3D printer from flammable objects or liquid.

Always 3D print at a lower speed and temperature. Doing so enables you to minimize the printer’s risk of igniting sparks from faulty wiring or when at excessive temperature levels.

You can use PLA filaments without a heated bed as well to mitigate this challenge.

Do You Need to Keep PLA Dry?

If you use one PLA filament roll for 3D printing per month, you need not store it in a dry box. However, if you use PLA filament for a year, you may need to put it in a dry container.

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As a caution, store all filament types like ABS, PET, PETG, and PLA in a low-humidity and dry environment. Although PLA filament doesn’t need to be dried, it is essential to note its sensitivity due to its hygroscopic nature.

As such, treat all filaments as if they are moisture sensitive. PLA filaments absorb moisture from the air when exposed to high humidity. Thus, PLA swells leading to poor 3D final prints characterized by air bubbles problem on top surfaces of objects.

As a 3D community member, you need to be aware of other challenges caused by leaving a PLA filament without storing it in a dry box. The challenges include increased stringing, inconsistent extrusion rate, damage to the extruder hot-end from air bubbles trapped inside the filament, and a loss of strength in the final prints.

How Do You Store 3D Printer Filament?

Humidity is dangerous to the filaments’ well-being, and you need to be careful with your filament storage issue.

You may store your 3D printer filaments in the following ways:

Vacuum Bags

A high-quality vacuum bag provides an air-free environment to store your filaments. It may be good to purchase these bags as they possess a vacuum valve that helps in sucking out the air.

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A good example is the type of vacuum bag that boasts a zipper mechanism that completely locks out air.

Dry-Packs Silica Gel Desiccants Packets

Dry-packs packets contain absorbent desiccants called silica beads-gel. The silica gel is a non-toxic product that absorbs 40% of its weight in water vapor.

Dry-pack silica beads gel (see it on Amazon) provides superior absorption while remaining dry at maximum saturation.

Dry Box

The dry box creates a moisture-free environment for filament storage. The dry box provides low humidity that is perfect for storing filament spools.

The technology works through an electronic dehumidifier system. The system dehumidifies the inside of the box constantly; as a result ensuring the container is airtight.

Related: How to Dry Filament

Storage Box

Using a transparent box with a sealed lid is a great alternative to store your filament. The idea behind sealed lids is to limit moisture from outside to reach the filament.

A transparent box also helps you monitor the filament from the outside.


Using a storage box is safe for your filaments, but you need to reduce the air trapped inside the box. You may need to purchase a dehumidifier as a solution.

How Do You Unload a 3D Printer Filament?

You can unload the filament spool from your printer by following these steps:

How Long Can You Leave Filament in the Extruder?

Most commodity filaments such as ABS, PLA, and PETG don’t have issues left in the extruder between printing sessions.

Filaments such as nylon need to be stored away from moisture to prevent them from absorbing it from the air.

Ensure you put your 3D printer in a warm room or introduce some setups that will protect the filament from moisture while in the extruder.

More practically, it would help if you stored filaments in an airtight container to protect them from moisture.

Leaving Filament Loaded in the Printer

Leaving the filament in a 3D printer may not be a bad idea if the environment isn’t too humid or hot. However, filaments like nylon and polycarbonate tend to absorb moisture in the air.

Filament quality goes lower if it absorbs moisture. Therefore, leaving filaments loaded in printers for a long time may make them brittle. When filaments become brittle, they produce low-quality prints.

Do You Have to Remove Filament After Printing?

If you attend a 3D printing forum, one of the questions guys ask is whether there is any need to remove filament after printing immediately.

The answer to this question is that the urgency of filament removal depends on the filament type. Most people experience no problem leaving filaments in the extruder.

However, some filaments like nylon absorb moisture in the air rapidly and get spoilt quickly compared to other types like ABS, PLA, and PETG.

Will Leaving Filament in a 3D Printer Damage It?

No harm will befall the filament or even the printer if you leave filaments loaded in the printer for an extended period.

The filament type matters a lot as different filaments behave in a particular way when exposed to moisture in the environment. ABS can stay loaded for weeks in the printer without any physical damage.

On the contrary, nylon absorbs moisture from the air rapidly, meaning it can get spoilt so fast.

Prolonged exposure to moisture is not suitable for many filament types. Consequently, developing a habit of removing the printer’s filament as soon as you finish printing portends well for it. You only need to let the hot end cool down completely before cleaning the filament.

After removing the filament, store it in an airtight container.


It will help if you rest assured that leaving filaments in a printer between printing sessions, in a way, doesn’t portend any danger. However, some filaments absorb moisture faster than others, meaning they get spoilt more quickly than their counterparts.

Removing the filament after printing and storing it in an airtight container or a dry box is a good practice that keeps filaments safe.

Michael Brooks is the founder of He sees a very bright future for 3D printing that's why his mission is to try and make this easy for everyone. Discover your hidden talent and creativity. You can follow here: Facebook, Twitter & Pinterest.