I am currently trying to load TPU into the new dual extruder. In the old single extruder TPU loading was quite difficult because the automated loading was pushing too hard and too fast which made the flexible TPU knot inside extruder case. I did it by openening the extruder service hatch and manually, slowly pushing the TPU into the hotend. Then printing would work quite nicely with the old extruder.
The new extruder seems to suffer from a similar problem as the old one, that the TPU is pulled in too fast and will then knot inside the extruder case. However with the new extruder, even though there is a service hatch itās almost impossible to manually push in filament because everything is quite a bit smaller and there is no real way of pushing the filament through manually. So I was wondering if there is a way to control the loading speed of the extruder and make it load stuff much slower so the TPU wouldnāt knot. However I could not find a setting for this anywhere.
I didnt try yet. If you need slower feed speed you could enter the speed and extrusion in the terminal like:
M83 ;relative mode
G1 E100 F20 ;extrude 100mm at a speed of 20mm/s
New test, I put the highest allowed temperature for the filament, 230C, and then it worked.
Next problem is that the model is a rectangle with a 0.5mm gap under each side. Its not possible to turn it so I need support. I tried pva on the second extruder but I dont manage it to print correctly with Luban.
Its a button for a remote so it needs precision under it.
I was finally able to do it. I connected it with Octoprint and then set the feed rate to 10% via the UI. Then I triggered the feeding via the UI as well. Printing TPU is pretty much hit or miss at the recommended temperature of 230Ā°. Half the time the filament is mangled up in the extruder at some point during print:
I was printing really slow with 10mm/sec and no retractions. I tried a few iterations with raising temperature and was finally able to get prints consistently printed without filament being mangled in the extruder at 250Ā°.
While this is workable the resulting prints donāt look very nice compared to stuff printed at 230Ā°. Here is a print at 230Ā°:
Note the much duller finish. At this point Iām really out of ideas on what to do, I love the 230Ā° results but there is only a 1 in 5 chance of getting a print through without mangling the filament in the extruder. The 250Ā° degree prints work every time but look really a lot āovercookedā.
Iād recommend switching to Cura for 3D printing. Luban works okay-ish for laser and CNC but the 3D printing part is very reduced compared to Cura. There is a lot more fine grained control over things in Cura so maybe give it a spin.
