Hi, I’ve been testing the new TPU filament from Biqu (Biqu Morphlex TPU 90A–75A). Initially, I had good results with small prints, but when I tried printing a larger object for a university project (a bronchial tree printed in a single piece), I started noticing some missing lines.
The print itself finished successfully, but there were small areas missing and, in some cases, entire layers were missing. This caused parts of the print to tear apart, as you can see in the images below.
The filament was dried before the print and also during the print using the new software update for the H2 series. It was dried at 65 °C for 5 hours in the AMS‑HT with the external PTFE tube installed.
Could it be caused by the retraction settings, the nozzle temperature, or even by the fact that the filament was being dried in the AMS‑HT during the print?
Principais correções:
These were my settings for this print:
Hi Joao,
Is this really all the information they provide about the filament?
https://biqu.equipment/products/biqu-morphlex-variable-hardness-flexible-3d-printer-filament-for-printing-shoes-1-75mm-1kg-spool-compatible-with-most-fdm-printers
That’s not much to go on. Does this stuff foam up, like other variable-hardness TPUs? Does it even explain on there how to adjust the hardness?
The other foaming TPU vendors I’ve looked at, like Siraya and colorFabb, recommend no (zero), or very little, retraction when foaming.
I used some Siraya PEBA Air recently, which is very similar to foaming TPU. I was trying to get rid of a few strings where it entered and exited the print (from the prime line at the start and then back to home afterwards). I told it to retract 0.2mm when it is going to travel more than 100mm. Well, it put down the prime line, retracted, went to print and for almost half the first layer nothing came out of the nozzle at all. 
Eventually it resumed coming out, to my relief because I immediately imagined a jam.
I had it foaming pretty good at that point (higher temp, lower flow rates). At the lower temp. range when it still acts more like regular TPU, the retraction issue wouldn’t be as drastic, but maybe something similar is happening in your case?
I don’t know how similar the materials are, but you may find some interesting clues in the Siraya version (they also have example project downloads with filament profiles).
https://siraya.tech/pages/siraya-tech-flex-tpu-air-tds
Or colorFabb: https://colorfabb.com/blog/post/how-to-print-with-varioshore-tpu
Cheers,
-Max
Your tpu feeding has too much friction or restriction.
You need something like this:
Mine works very well with Morphlex.
