The filaments used for 3D printing are thermoplastics. This means that rather than burining like other types of plastics, or polymers as they are technically called, they melt. It’s this quality that allows a thermoplastic to be molded into a 3D shape that solidifies upon cooling.
Plastics that burn when exposed to heat are thermosetting polymers. Unlike filament, they cannot be melted down and reshaped after they have solidified. Thermoplastics can take up to 450 years to break down. Does this mean filament cannot go bad and can be used forever? Not quite.
3D printing filament does go bad but only under certain conditions.
In this guide, we explore how long filament lasts and what prolongs its shelf life. We show the common signs of filament that have gone bad as well as how to print with old or expired filament.
Does 3D Printer Filament Have A Shelf Life? (Types & Life Span)
The lifespan of a thermoplastic ranges anywhere from a week right up to 15 years. The main determinant of lifespan is the conditions in which the filament is stored. Properly storing filament in airtight containers prolongs its lifespan.
But why is storage so important and how does it affect the expiration of filament? Depending on how you store it, filament will expire sooner or sometimes last longer than the expiration date given by the manufacturer. Before we look into how to store filament, let’s look at how long different types last.
PLA
Polylactic Acid or PLA is the most popularly used filament. It has the lowest melting point of between 180 to 230 degrees Celsius (356 to 446 degrees Fahrenheit). It’s also the cheapest filament which makes it ideal for beginners and heavy users.
PLA has a shelf life of between 2 to 3 years when stored properly.
Aslo, check out our post “Signs Of Bad PLA Filament: What To Do About It!“
ABS
Acrylonitrile Butadiene Styrene or ABS is another commonly used filament. ABS has a slightly higher melting point than PLA at between 210 to 250 degrees Celsius (410 to 482 degrees Fahrenheit). Like PLA, ABS is also popular with beginners because it is easy to use.
ABS also has a shelf life of between 2 to 3 years when stored properly.
Nylon
Nylon is a popular alternative to PLA and ABS. Also used to make toothbrushes, Nylon has a melting point of 240 degrees Celsius (464 degrees Fahrenheit). One of the biggest attractions of using nylon is its ability to produce flexible prints or models.
Nylon has a short shelf life, maxing out at 12 months.
PETG
Polyethylene Terephthalate Glycol or PETG has a melting point of between 230 to 250 degrees Celsius (446 to 482 degrees Fahrenheit). PETG is more UV resistant, flexible, and durable than PLA. This makes it more suited for outdoor use where it will be exposed to direct sunlight. Source
PETG has a shelf life of 2 years.
Those are four of the most commonly used filaments and how long they last before they start to degrade. Different brands will have their expiration dates for their filaments so it’s important to check with the manufacturer and use that as your final guide.
For more on this, check out our post ” Does PLA Have A Shelf Life? How long & How To Store It for A longer Shelf Life!“
But how do you tell when filament has degraded and what causes it to go bad?
How Do I Know If My 3D Printer Filament Is Bad?
Filament that has gone bad produces poor prints. This can be observed as cracks, bubbles, holes, and other inconsistencies in the print. Another common characteristic of bad filament is the printer gets clogged or jammed up when the filament is extruded through it.
There are several other ways to tell whether the filament you want to use has gone bad. The most common is hearing a snapping or popping sound when you run the filament through your printer.
Filament that has been out too long will also lose its adhesiveness. It will not stick to the printer base which will make using it almost impossible.
Aside from being difficult to use, bad filament results in prints that don’t look or function as they should. A model made from bad filament will likely have poorer impact resistance for example. The final result is a print that is either aesthetically or structurally inferior.
What causes filament to go bad?
Filament degradation is primarily caused by moisture absorption. Filaments are hygroscopic, or in simpler terms, they absorb moisture. The moisture alters the composition of the filament and makes it weaker.
High moisture content will swell up the filament and cause cracks or bubbles to form in your prints. In some cases, it can even damage the printer itself. Some filaments like Nylon absorb moisture quicker than others.
Light can also degrade filaments. Exposing filament to direct sunlight will also break down the chemical composition of filament.
Also check out our post “Can You Leave Filament In A 3D-Printer? How To Deal With It!“
How do you prevent filament from going bad?
The best way to keep filament in good condition for as long as possible is to store it properly. Filament needs to be kept dry and away from light to retain its core properties. There are several ways to do this including using food containers, Ziploc bags, silica gel, and dry boxes.
Storing your filament in airtight containers and adding silica gel to absorb moisture just about guarantees that your filament lasts longer.
Check out our recommended storage case (Amazon link)
OR for a budget option, You could go for a Cheap filament Storage Bag (Amazon Link)
How Can You Tell If PLA Filament Is Bad? (Simple Examination)
A simple way to tell if PLA has gone bad is to examine the prints. If the prints are brittle, weak, or break easily, then this is a sure sign that the filament has gone bad. The most common cause of this moisture absorption.
Filament that has been exposed to high humidity will swell to a thicker diameter and have bubbles in it. When you try to run it through the extruder in your printer it may jam up the machine.
For more on this, we recommend that you check out our post ” Why Does My Filament Keep Breaking? Fix PLA Filament Snapping!“
What Happens When You Print With Old Filament?
It’s possible to print with old filament and get good results. Naturally, it depends on what condition the filament is in. The best way to use old or expired filament is to first test with a small run to see what type of results it produces.
It’s also a good idea to preheat and dry the filament before you try to use it. This removes any moisture that might be present in the filament. Source
