TPU and PETG
My first time printing with TPU. I wanted to mix PETG and TPU in a coaster design. The first layer prints fine but after that the TPU tool head just goes through the motions and doesn't print. PETG tool head is fine of coarse. I thought it was a TPU issue so a print a Becky with the TPU tool head and it came out fine.
I did have to unload the TPU and reload it before I printed the benchy so I think there is some kind of issue with the time between the tool head changes. Anyone else have this issue? Or better yet, a solution?
Thanks!
PETG and TPU are not particularly keen to stick together so I find it best to feed the TPU directly to the print head, bypassing the tubes, and setting the idler tension as light as possible; you do still need a very light tension in the filament so that retractions work.
Prusa's interlocking infill (beam interlocking) does help to join sections but is not always ideal, I tend to design flexible interfaces with closed loop anchors so that they cannot separate.
The above geometry, for example, will make a strong TPU hinge between rigid plates.
Cheerio,
RE: TPU and PETG
I had a similar issue with filaflex 40 and esun 83A. If i print an object on its one it was fine but when printing with multiple heads at some point it stops. I found out that in the latter case the filament was "tangled" in the gears. At first i played bit the two tension screws. This actually helped but the problem returned with the softer esun 83A. At this point the only thing that actually solved the issue is increasing the temperature. This of course cause a bit of stringing. As we speak im printing a 16 hour PETG with TPU and having PLA as supports. I printed this part 3 times until now and not once i got the issue again.
Another thinng that helped was printing a sensor bypass while loading the tpu to the head.
https://www.printables.com/model/1147649-prusa-xl-filament-sensor-bypass-for-pc4-m6-m6-inse
RE: TPU and PETG
The TPU and PETG are bonding greatly. No pealing even if I try. I am just printing coaster so it's not a great test of the bonding strength but I did reference this Filament Combinations before I started.
RE: TPU and PETG
I ended up changing the idle temperature for the TPU to 170˚ C and everything is working great now. The TPU has been in a dry box since I opened it, but it could have been wet when I started and the drying of it solved the problem. Unfortunately I won't know what actually fixed it, but its working now 🙂