How To Fix PLA Getting Brittle
It’s frustrating how your attempt to print a 3D prototype results in having the PLA filaments breaking off at the slightest touch. We know that PLA widely use in 3D printing, but their tendency to go brittle has frustrated many hobbyists and professionals alike.
A roll of brittle PLA filament results in broken pieces, reduces texture strength and causes uneven extrusion during the printing process.
Various theories have explained why the PLA filament keeps breaking apart during print. Users also seek ways to overcome the brittleness of the filament. Before we explore the available options, let’s dig deeper into the potential causes of such incidences.
Why PLA Filaments Get Brittle?
Both experts and regular users couldn’t agree on the brittleness causes, with each holding on to their respective arguments. However, chances are, there is more than one contributing cause that makes the PLA filament brittle.
For a start, PLA, which stands for poly-lactic acid, is known to be relatively brittle. The property means that it is inherently brittle to a certain extent, particularly compared to materials like ABS. PLA is also known to degenerate rather rapidly, which explains why it eventually snaps off during printing.
The degeneration process of PLA filaments could take months, but some conditions could further aggravate the material’s flexibility. A commonly circulated theory is the moisture adsorption by the filament. When placed in a humid environment, the filament absorbs moisture from the air and alters its physical properties.
Usually, the reel’s outer part starts getting brittle as they expose to moisture. To make things worse, the attempt to straighten a rolled filament applies mechanical stress beyond the tolerance of its altered flexibility. This can explain why the filament keeps breaking off when you tried printing with it.
In some cases, color additives that add to the filament may change its mechanical properties. For example, you may have black filament snapping off quickly while transparent PLA works fine in the same environment. Occasionally, it could be the quality of the filament itself that is the culprit.
Fixing PLA Filaments That Have Gone Brittle
Are there any fixes when the PLA filaments have gone wrong? There is a slight chance of getting the filament into its original form by applying heat to it. The theory that supports this suggestion is that the heat would cause the moisture to evaporate, leaving the PLA in its original structure.
Here are two ways of using heat to dry the PLA filament.
1. Heating The PLA Filament Roll
In some instances, heating the entire filament roll may reverse its brittleness. This is assuming that the changes in its physical properties are still reversible.
Place it in an oven for 2 hours and check out if the flexibility has returned. You’ll want to ensure that the temperature does not exceed 50°C when you’re heating the entire roll of filament. You mustn’t exceed the suggested heating temperature as the whole reel may turn soft and rubbery.
Repeat the process if you feel that the brittleness has decreased but yet to reach the ideal level. After heating the roll of filament, you could check if it’s still brittle by bending the filament and see if it breaks off.
If these attempts failed, you could try cutting 2-3 meters of the filament off the roll. In most cases, only a short length of the filament is affected while the remaining is in its original condition.
2. Increase The Nozzle Temperature
If you’re having issues with brittle 3D prints, you could increase the temperature of the nozzle. This action ensures that sufficient heat is applied to evaporate the moisture and soften the PLA filament’s physical form. You’ll want to try a few different temperatures to get the outstanding value that works.
However, You should note that these methods may not be effective if the physical properties of the PLA are altered permanently. If the PLA material has gone through irreversible molecular changes, no amount of heat will fix its brittleness.
You’ll have to replace the brittle PLA filament with a new one if the above suggestions don’t solve the issue.
Prevention Measures In Handling PLA Filaments
When dealing with brittle PLA filaments, prevention is always better than cure. If you’re having regular issues with PLA filaments snapping into pieces, you’ll want to stop leaving the filament on the 3D printer after usage. Instead, ensure that the filament retracts into the reel after printing and store in a sealed pouch or container. If possible, place desiccant in the storage to ensure that excessive moisture is removed. This prevents moisture adsorption from weakening the structure of the filament.
Besides that, you could also cover the reel of PLA filament that you’re currently using with a plastic bag and puncturing a hole for the filament to be fed to the 3D printer. This method minimizes the chance of moisture being absorbed into the PLA material.
As mentioned, the physical properties of PLA alter by temperature, moisture, and additives. You’ll want to be diligent when ordering supplies of PLA filaments because improper handling may result in brittleness of the material. Try bending a new roll of PLA filament to ensure that it’s in proper condition.
Summary
There’s no quick fix to brittle PLA filament. Heating and drying may not always be successful. It is better to have a habit of storing unused PLA rolls in a dry environment and ensure that you’re getting the material from a reputable supplier.
I have few kilos of PLA and Soft PLA (from orbitech) that gone brittle, you touch it and it will break… I tried heating it to 50C in a food drier for 5 hours – didn’t help, tried heating it to 70C for 5 hours, didn’t help, tried leaving it in food drier for 24 hours at 50C – didn’t help, thrown it away finally.. it became brittle after sitting on a shelf for few years, during summer, in that room, it gets super humid (80%+) and hot (30-35C) during winter it gets super dry (20%-) .. the filament went trough few of those phases and ended up unusable, tried heating it, adding moisture, removing moisture nothing helped..
You could have a trial with our PLA filament, we use resealable package and don’t need to store in oven.
Brand new roll of white eSun PLA for me, very brittle straight out of the packet. No settings changed in the slicer. Last batch of eSun filament I bought was perfect. Frustrating, I have 4 rolls of PLA, same vendor, nervous to open the others now.
@Jimmy I have the same problem. New roll of Cool White PLA+ from eSun. Terribly brittle. All the other filament I get from them is good. Hoping this was a bad batch
HAHA, I came here from a search related to eSun PLA+ very brittle! I too have several brand new rolls of eSun PLA+ that are defective right out of the vacuum sealed bag! And I’ve used this brand successfully for a few years! My prints started to immediately string and I’ve never experienced this before!
Had the same issue with eSun warm white PLA+. Other eSun PLA colors were fine.
wow, I also have the same issue with a new roll of eSun white PLA+ I have bad stringing and layer adhesion. tried printing a couple of temperature towers and they look terrible at every level, which is not a normal result in my experience.
Yeah, white is more brittle than another color.
About PLA plus filament, they have combined with other material inside; maybe it is PHA. The natural color of PLA plus is not transparent, and they need to add so much dye to make the white color. The too-high filler will affect the properties uniform of materials,then it more like to brittle.
Chanced upon this link. Never had the problem is 5 years until this reel of black pla. I can feed it into the tube, print whatever I like just fine. Finish the print. Walk away, and next morning it has snapped not only outside of the extruder, but in it, and in the tube. Never figured it out, but at least I can print with it as it never snaps until after the print.
pla needs moisture
I too have had recent troubles with eSun being brittle right out of the packaging. I’ve been using the same color filament from them for 6 months with no problem and the last two rolls that I had purchased (during Covid-19) have been bad out of the box. My guess is Covid has caused some restrictions that is causing issues with the manufacturing process. Either way, not good for business. I will no longer purchase eSun since I can’t trust them any longer.
A lot of folks discuss excess humidity. However, I believe it may be the opposite. My environment is very dry–about 12% humidity. It was at this time the filament became brittle. I can get it to print just fine, but when I leave the printer set up overnight, the filament between the extruder and hot end will be in 2 or 3 pieces by morning. The only solution has been to remove all filament and re-thread the printer immediately prior to a print.
I recently started using some olive green PLA+ from eSun and keep getting brittle filament breaks. It’s very frustrating because it has ruined a lot of long print jobs.
I’ve never had problems with eSun PLA+ and have been quite fond of it actually. I guess I will know if their quality has taken when I open up another fresh roll tomorrow.
Hi John,
Actually, there are so many factors with PLA filament brittleness, such as storage, resin.
The resin properties differ from the manufacturer. According to our experience, Ingeo 4032D/4043D(NaturalWorks) is better than Total Corbion PLA.
You could test with another batch.
Barret