It's mid way through the school year and your 3D printer is acting weird. You know that it's well calibrated but the first layer has a hard time printing and the parts aren't sticking like they used to. You might even be experiencing frequent clogs. If this is the case, then old plastic may be to blame. In this article, we'll look at why this happens, how to tell if your plastic is old, and what you can do to minimize waste.
Why is old plastic an issue?
Old plastic causes problems in 3d Printers. After you open the bag that it came in, you have about 6 months to use the spool before it starts to become an issue. Exposure to the moisture in the environment and UV light will degrade the plastic over time, so the spool of filament that you started with at the beginning of the school year likely wont get you to the end of the year without causing issues with your machine.
What are the signs that my plastic is old?
If your plastic has been out of it's packaging for more than 6 months and you are experiencing issues with your printer, like clogs and first layer adhesion problems, then your plastic is likely too old to be used. Always start your troubleshooting by running a First Layer Calibration.
First Layer Calibration Test Anomalies
If you run a first layer calibration and you are confident that you have dialed the machine in well, but you are still seeing the plastic peeling up as it is being laid down, this is a good sign that your plastic is too old. If you see the edges the test square curl up it is also a sign that it's time to switch to a new spool. Another clue is that the test bead that the printer lays down is sticking well in some spots and in other spots it wont stick at all (assuming you are printing on a nice clean bed free from fingerprints and dust).
Unload the filament from the extruder and discard about a foot of the material from the tip. Using the newly exposed end, try folding the plastic in half. If the plastic snaps in half, then you should definitely toss that spool in the recycle bin and load up a new one. If your spool passes the snap test, this does not mean that you are in the clear. You should use your best judgement based on the information above.
Hissing and Steaming
A clear sign that your plastic has absorbed too much moisture from the environment is if you can hear a hissing sound and the plastic is extruded or if you can see steam coming out of the nozzle. This is an extreme case but a clear sign that it's time for a change.
How can I preserve the plastic?
The best way to keep from having to throw away old plastic is to only open one bag at a time per machine. You can get many, many FUSE prints from a single spool. Dozens and dozens if not a hundred or more. If you have several spools open so that your students can choose from many different colors, you may find yourself throwing away more plastic because the spools wont all get used up before the plastic "expires".
If you do have some spools that you want to preserve, first check to see if your spool came in a ziplock style bag. Replacing it in the bag can help prolong it's life. If you have an airtight plastic container, and better yet have desiccant in the container, you are likely to extend the life of the plastic even further.
What happens if I don't change the plastic?
If you continue to use the old, degraded plastic, you may be asking for trouble. Continued clogs and failed prints are not far off.
Can I recycle old filament?
Researching filament recycling services in your area or use the general blue recycle bin in your school are your best bet. As it stands, filament recycling units available to the consumer are costly and provide mixed results.