TPU95 print has holes on the top - no issues before

[icekamp 0]

Dear All,

 

I hope that you can help me to solve my printing problem. I want to print multiple slider in one "go" and in the past this worked with an acceptable result. Now, the print gradually gets more and more holes. How can this be happen? Do you have an idea?

 

I am using:

Ultimaker 3 extended

Ultimaker TPU95, white

Cura 4.7.1 (although the file might be one version earlier)

 

The Cura file as well as a photo are both attached.

 

I performed already multiple prints prior, using or not using the "support" function/ same material as well as supportive PVA. But actually, I do not think supportive material is needed.

 

Please let me know, which information is missing.

 

Thank you very much in advance!

UM3E_Slider 02.3mf

[gr5 2,099]

during testing, just print 3 or so at a time until you figure this out, then you can print as many as you want.

 

Your issue is major underextrusion.

 

It *might* be related to stringing.  You can try "print sequence" set to "one at a time" mode.  That will help with stringing.  It's possible if it strings a lot then when it's printing the actual part it doesn't have enough filament but I dont' see much strings so that's probably not it.

 

TPU is tough to print as it's so flexible.

 

I'd try printing at 1/3 speed just to see if that helps.  In fact you can mess with this while it's printing in the TUNE menu and this is much more informative if you are only printing 2 or 3 of these at a time (faster feedback to know if it's working).

 

Also with TPU people think it's crazy and will mess up the print but it doesn't: add a drop of oil to the filament below the feeder.  The oil will end up in the bowden and the filament will slide through much more easily instead of bunching up.

 

Also maybe increase the temp just a little - maybe 5C or 10C.  If you increase it too much you will get stringing.

 

Also adjust flow.  You should be able to do this also in the TUNE menu on the printer live.  Typically you want around 105%.

 

Also maybe set the tension on the feeder to the smallest setting (all the way at the top).  If you squeeze the filament too much when you ask for 10mm it actually only gives you 9mm or something because it's making the filament longer while it goes through the feeder and then shrinks again.

 

Try flow higher flow values but if you go too high you get bunching and then completely failed prints.

 

[icekamp 0]

gr5, you are amazing! Such a fast and especially detailed answer! I highly appreciate that! Thanks a lot!

 

Tomorrow, I will start with testing those suggested settings on 3 parts at the same time; to have at least a bit the feeling of multiple prints at the same time.

 

Have a great Sunday evening!