Issues with printing TPU filament on my MK3S
Hello!
I'm fairly new to 3D printing and this is my first time trying to print with TPU (Ninjaflex 1.75mm). I've read a few different posts about other people who have had similar issues when it comes to TPU. I'm using a stock Mk3S. My issue seems to be that the extruder is not gripping the TPU to send it out the nozzle. I end up getting a lot of dotted lines instead of full layers. I've read that there are parts I can print to upgrade my printer but I'm not sure exactly what the best fix might be. Would anyone be able to help me out with this?
Thank you!
RE: Issues with printing TPU filament on my MK3S
for starters, Ninjaflex at 85A while being a wonderful filament, (Frankly it's my favorite flex) is far from the first flex you should be printing, you may want to try something in the 98A range to start, maybe the 95A range, get a feel for what it is your dealing with and move forward from there. it takes time to get used to printing flex filaments, the MK3S stock is very completely capable of printing them stock, you don't need new hardware you need patience and knowledge.
The Filament Whisperer
RE: Issues with printing TPU filament on my MK3S
I've had good success with 85A TPU on a stock machine. The grip was what the manual recommended (the tensioner screw head pretty much flush with the extruder body). Are the "dotted lines" coming from the nozzle when it's just raised, or only when it's printing? If it's the latter, then it could be that your Z offset is too high. Also make sure that you're using a release agent if using the Smooth PEI Bed 🙂
RE: Issues with printing TPU filament on my MK3S
I have printed some NinjaFlex on the MK3S and with success. The MK3S is better at printing flex than MK3 with the better filament path.
It may seem contra dictionary that the filament pressure screw should be loose when printing flex to get at better grip, but I usually give the screw two turns to loosen the grip.
If the flex filament is pressured too much it flattens and will not be pushed into the extruder PTFE tube the right way often resulting in it coming out the side of the extruder or not feeding at all (I think this is your case).
Have a look at my models on Printables.com 😉
RE: Issues with printing TPU filament on my MK3S
@swiss_cheese
Thanks for your reply!
I totally agree that I need more experience haha. I appreciate the tip and will look into the 98A (I didn't even think about using different shore hardness before this!)
RE: Issues with printing TPU filament on my MK3S
@area51
I actually tried tightening the screw but not loosening it. Thanks for the idea!
RE: Issues with printing TPU filament on my MK3S
@koyo
The dotted lines I believe are the result of not enough filament being pushed through. I'll be using kapton tape to make sure I can remove it from the bed. Thanks for your help!
RE: Issues with printing TPU filament on my MK3S
@skyler45
I did it wrong too the first time I printed with flex.
Thinking about it, it is logical not to flatten the filament... but not at first...
Have a look at my models on Printables.com 😉
RE: Issues with printing TPU filament on my MK3S
@skyler45
I got my first spool of flex filament today so have no experience at all with printing flex.
But whenever I get a new material I have a look at the Material Guide in the Prusa Knowledge Base for more info. There are many good tips in there.
There is mre useful info in here