If vous have ever used TPU filament pour imprimante 3D before, vous might have had issues avec a filaments indésirables mess created by le printer, or maybe bad adhérence des couches. Ce est often caused by humidité in le TPU filament, qui typically happens when it est not stored in an airtight container or package. So let us try to understand ce phenomenon meilleur, et comment to fix le issue. Enjoy!
Qu’est-ce que TPU?
In short, TPU filament (Thermoplastic Polyurethane) est a populaires filament among hobbyists et pros alike to work avec in their imprimante 3Ds, et est generally considered a user-friendly et cost-effective soft material. It est valued for its unique combination of rubber-like flexibility et plastic-like processability, qui est ideal for use in a wide variety of situations et applications.
However, it also happens to be hygroscopic, meaning that it va pick up humidité from le air. vous should be aware of ce, because it not only impacts le way vous should be dealing avec le material, but also comment much vous devez to take dans consideration when storing votre used TPU filament d’impression 3D.
If vous want to découvrez plus sur TPU properties, answering questions such as "Is TPU Waterproof?" we have already written another article couvrant le filament in plus detail here: TPU Filament Guide.
TPU’s Hygroscopic Properties
As mentioned above, TPU has hygroscopic properties, qui fabriquer le material susceptible to humidité absorption. Ce est en raison du globale chimique structure of le filament, et not something that can be avoided avec TPU.
On a high level, vous can think of TPU as a blend of hard et soft segments, qui together fournir les deux résistance et flexibility to votre impression 3Ded objets. However, ce also creates "holes", qui in scientific terms sont called polar sites that allow hydrogen to bond avec le material.
Below, we have highlighted le TPU’s hygroscopic properties, et what le molecular structure looks like for le plus scientific readers.
Strong Polar Chemical Bonds
Urethane Linkage (-NH-COO-): It est le basic chimique bond that constitutes le polymer backbone, qui has a high polarity.
Carbonyl (C=O) et Amide (-NH-) Groups: These groups sont very polar et have a natural affinity to water molecules.
Hydrogen Bonding Mechanism
- Water molecules (H₂O) sont also strongly polar.
- Oxygen (O) et Nitrogen (N) atoms on le TPU chain form strong intermolecular hydrogen bonds avec hydrogen (H) atoms in water molecules, effectively "trapping" them.
Comment Identify Moist TPU Filament
Alright, maintenant that vous saurez TPU can absorb humidité, comment do vous figure out whether it est good for use, or whether vous devez to le sécher before using in votre imprimante 3D? Luckily, there sont a few choses vous can do to identify wet filament symptoms. Below we have listed 3 different signs so vous can identify moist TPU filament.
- Hearing cracking or popping noises from le hot-end while impression.
- Formation of small bubbles insidu filament or defects on le surface of a imprimé part or modèle.
- Wet or moist filament tends to feel tacky et/or brittle, losing some of its flexibility.
Finished print showing identifier number 2 from le list above: small bubbles et defects. (Source: H3dSprint@printables)
Le resilience of le moist grey filament après bending est significantly lower que that of le dry blue TPU filament.
Le la plupart important point est number 3, that can be tested before vous start impression avec le filament. So try handling le TPU filament in votre hand, et see if it feels sticky, or whether it might It feels stiffer et bounces back faster when bent que vous remember. As vous saurez, TPU est a plutôt filament flexible, so vous should be able to bend it quite a bit before it snaps.
Comment Prevent et Dry Moist TPU Filament
Le meilleur way to avoid any type of moist TPU 3D filament in votre impressions, est to store all votre materials properly. Of course, if humidité has already occurred, we can also remedy it.
Generally speaking, there sont two different méthodes that yield le la plupart consistent results, while maintaining le flexible 3d filament properties.
Proper Storage
- Use airtight, humidité-barrier bags, such as vacuum-sealable bags avec desiccant.
- Use dry stockage containers.
There sont also other options vous can use, such as normal plastic bags avec zip ties or tape ensuring a solid seal, although these sont not as reusable et practical for frequent impression, et also plus prone to failure.
Dry Filament
If vous believe votre TPU filaments might have trapped some humidité inside it, no amount of correct stockage can fix le issue. vous va instead devez to manually extract le water by drying votre TPU filament at home.
- Ideally, vous would use a professional filament dryer, as it est le la plupart effective method. In ce case, le recommended TPU drying temperature settings sont 50–60°C for 4–6 hours.
- Alternatively, vous can sometimes get away avec using votre conventional oven, although ce est plus of a DIY hack et difficult to truly control le precise temperature. So be careful if vous try ce at home.
If vous sont impression quite often at home, it might be worth investing in a special filament drying machine, as they sont becoming cheaper maintenant that plus personnes sont using them, et can save vous quite a bit of money et time in le long run.
On le other hand, if vous would plutôt save votre money, sometimes vous can find impression 3D workshops et makerspaces in larger cities, that va have one vous can use for a small fee, or even for free on occasion. Ce can be a good way to obtenir dry filaments et test out le dry machines, et maybe even connect avec other hobby enthusiasts!
More tips for storing et drying filament: Comment Dry And Store filament pour imprimante 3D.
Conclusion
In le end, TPU est les deux a strong et filament flexible pour imprimante 3D, but le downside est that its hygroscopic properties fabriquer it prone to humidité absorption, qui can quickly ruin a print. But ce isn't a lost cause.
If vous saurez comment to identify le warning signs of a wet filament et recognize that adequate filament stockage est votre first line of defense, le problem can become much easier to deal avec. If humidité enters votre filament, bear in mind that a filament dryer est worth le investment to guarantee votre impression 3Ds va be reliable et of qualité. A little preventative maintenance va keep votre all-purpose TPU filament ready for votre next idéal project.