A bunch of friend and I bought a chinese prusa kit in order to learn a bit more about printing, from what i see the printer won't be able to print TPU out of the box.
I was wondering if I can eventually upgrade some parts and be able to print TPU, can you point me in the right direction?
The real problem when printing in flexible materials is the way the filament is feed into the hot end. You'll need a direct drive extruder where the hobbed gear is right at the entrance of the hot end. Imagine trying to feed a length of rope through a narrow tube. The rope will keep bunching up on you unless you push right at the hole. If that makes since.
13-Jul-2016, 05:06 PM (This post was last modified: 13-Jul-2016, 05:09 PM by Patrick. Edit Reason: Missing Letters / Verbage )
Here is my experience of printing TPU on my Kossel mini.. I don't intend to parrot what others have said here but in the course of explanation I undoubtably will. The feed into and out of my extruder needed modifying, there is no way it will retract with out the back pressure from the long bowden tubing causing it to kink and jam. So unless you have a short filament path out of your extruder then you may run into similar conditions. A quick search should show a few fixes for this.
Printing temperatiures will no doubt vary between filament sources, mine was happy at the low end of recommended 210-240c. I have an E3Dv6 and it handles deposition really well but with TPU only at low low speeds on my setup, around 10mm/s to be very safe to around 20mm/s pushing it.
One thing that threw me was cooling, I saw many guidelines stating that cooling TPU was a bad idea, maybe with a delta printer specifically this was the case for most users however, with my setup a lot of cooling worked wonders, setting the TPU before it glooped but slowly enough to let it adhere to the bed and previous layers.
The bed temperature was a surprise, 30-35c was fine with TPU in my experiments, much more than that and the heat build up in the print was becoming an issue early on in the printed part.
That just about covers my experiences of TPU with my Kossel Delta, its an awsome material, I have made all manner of flexi mounts, rubberised guards and cam mounts, it is uber durable.
Hope this helps!