PVDF: The Specialized Filament For Chemical And Moisture Resistance

There’s a dizzying number of specialist 3D printing materials out there, some of which do try to offer an alternative to PLA, PA6, ABS, etc., while others are happy to stay in their own niche. Polyvinylidene fluoride (PVDF) is one of these materials, with the [My Tech Fun] YouTube channel recently getting sent a spool of PVDF for testing, which retails for a cool $188.

Some of the build plate carnage observed after printing with PVDF. (Credit: My Tech Fun, YouTube)
Some of the build plate carnage observed after printing with PVDF. (Credit: My Tech Fun, YouTube)

Reading the specifications and datasheet for the filament over at the manufacturer’s website it’s pretty clear what the selling points are for this material are. For the chemists in the audience the addition of fluoride is probably a dead giveaway, as fluoride bonds in a material tend to be very stable. Hence PVDF ((C2H2F2)n) sees use in applications where strong resistance to aggressive chemicals as well as hydrolysis are a requirement, not to mention no hygroscopic inclinations, somewhat like PTFE and kin.

In the video’s mechanical testing it was therefore unsurprising that other than abrasion resistance it’s overall worse and more brittle than PA6 (nylon). It was also found that printing this material with two different FDM printers with the required bed temperature of 110°C was somewhat rough, with some warping and a wrecked engineering build plate in the Bambu Lab printer due to what appears to be an interaction with the usual glue stick material. Once you get the print settings dialed in it’s not too complicated, but it’s definitely not a filament for casual use.

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MorPhlex: The TPU Filament That Goes Soft After You Print It

In FDM 3D printing cycles TPU is a bit of a special filament. Not so much because of its properties, but because it’s rather stretchy even as a filament, which makes especially printing certain hardness grades of TPU into somewhat of an nightmare. An interesting new contender here comes from a company called BIQU, who reckon that their ‘MorPhlex’ TPU solves many of those problems. Recently the [ModBot] channel on YouTube got sent a spool of the filament for testing.

The BIQU MorPhlex TPU filament being turned into squishy slippers. (Credit: ModBot, YouTube)
The BIQU MorPhlex TPU filament being turned into squishy slippers. (Credit: ModBot, YouTube)

The ‘magic’ here is that this TPU claims to be a 90A TPU grade while on the spool, but after printing it becomes 75A, meaning a lot softer and squishier. Perhaps unsurprisingly, a big selling point on their product page is that you can print squishy shoes with it. Beyond this is claims to be compatible with ‘most FDM printers’, and the listed printing parameters are typical for TPU in terms of extruder and bed temperature.

After drying the filament as recommended for TPU in general, test prints were printed on a Bambu Lab H2D. Here BIQU recommends not using the AMS, but rather the dedicated TPU feeding channel. For the test prints some slippers were printed over the course of two days. In hindsight glue stick should have been applied to make parts removal easier.

The slippers were indeed squishy, but the real test came in the form of a Shore A hardness meter and some test cube prints. This showed an 80 – 85A for the BIQU MorPhlex test cube depending on whether to test the side or top. As the product datasheet indicates a final hardness of 75A +/- 3A, one could argue that it’s kind-of in spec, but it mostly raises questions on how parameters like temperature and extrusion speed affect the final result.