Does PLA Have an Expiration Date?
Polylactide (PLA) is a biodegradable polyester made from renewable resources including corn starch, tapioca roots, or sugarcane. PLA was the second highest consumed bioplastic in the world in 2010.
Within as little as a month, to up to two years, PLA will break down when exposed to the environment. While not soluble in water, PLA does absorb a lot of water. This excellent study found that when immersed in water for 30 days, PLA had a 1–6% weight gain, demonstrating its absorption of water.
Most people don’t store their filament in water, (If you do, I would urge you to find a new storage technique) but filament exposed to humidity has the same ability to absorb moisture from the air.
What harm does moisture have on filament?
Absorbing moisture causes filament to swell. Swollen filament can then jam extruders and destroy a hot end. A wasted roll of filament could lead to a sunk cost of maybe $40. A ruined hot end could cost upwards of $70 and could hugely delay printing- destroying productivity for a week or more.
The heat of printing causes the moisture trapped in filament to evaporate and turn into steam. This leaves bubbles and gaps in a print, not only ruining the appearance of the print, but also destroying its strength. The more moisture filament has absorbed, the weaker the prints produced will be.
How can this be avoided?
- Avoid buying more filament than can be used in a year: unused filament shouldn’t be kept for more than 12 months
- Store open filament in an air-tight container with silica packets to absorb any moisture that seeps in (LEARN MORE ABOUT OUR SOLUTION FOR THIS HERE)
