In this article you will find some information that will help you to master the TPU
Note: This article contains advanced information regarding TPU. The default settings for our BCN3D TPU have been tailored for good quality and reliable results, and are fully tested by our laboratory. These tips complement those settings to ensure the best quality in printing with TPU and flexible materials.
TPU (Thermoplastic Polyurethane) is an elastomer used for 3D printing components with flexible properties and resistance to oil, grease, and abrasion. It is a popular material that can be found in mobile phone cases, wire jackets, hoses, automotive gaskets, footwear, and many other objects that require elasticity.
This material is soft and quite tricky to print, but once you get the hang of it, it delivers amazingly flexible prints that will impress your customers and friends. Here are some tips that will help you in printing TPU.
Tip: Check out this material compatibility chart, it will help you choose the materials that fit best with TPU:
Store it well
TPU is highly hygroscopic, which means it absorbs a lot of moisture from the environment, and it does this quite fast. When this happens, the TPU polymeric chains break down as the material heats up, making it foamy and not smooth. This can cause clogging and various printing quality issues related to the part's strength.
If you want to prevent this from happening and know a bit more about this phenomenon, check out our guide on how to solve this common issue:
As an added tip, for longer print jobs stuff some silica desiccant sachets inside the TPU spool to prevent moisture from getting in it.
This filament is quite sensitive to UV radiation, and it will degrade if it's exposed to natural light during a fairly short period of time. Make sure to store the TPU spools in a dry and dark place, such as a closet.
Low and slow
TPU is a very soft material, and if it moves in and out of the nozzle many times it can get stuck in the hotend. Lower the retraction distance to 2mm and decrease the retraction speed to 20mm/s to prevent clogging and underextrusion, the less retractions the better. Keep in mind that if you lower the retraction distance, it can cause some strings to appear in the print, those can be easily removed with cutting pliers or a scalpel.
It also needs to be printed as slow as possible, if you force it through the nozzle at high speeds, it will get trapped in the bowden tube and cause a clog. The recommended speed for TPU is around 25mm/s. Tighten the extruder motor thumbscrews to the max setting to ensure a good grip on the filament.
Being a soft and flexible material, TPU can lead to failed prints because of the stability of the model itself. To ensure a stable print, larger nozzle sizes work best for TPU (they also help in clog prevention), as well as triangle structure supports.
You can also modulate the flexibility of your printed parts by adjusting the wall line count and infill percentage -Lower percentage and line count, more flexible parts-.
Need more tips? Check out our forum community for more info about this.
It's important to keep your printer in good shape to make the most out of it. In this chart, you can find a list of the extruder maintenance procedures and how frequently these should be done.
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