This is my first time printing with TPU after modding my machine to Direct Drive, I’m wondering if this finish is to be expected with TPU or should it be smoother.
Printing at 30mm/s across the board with prusaslicer, filament is dry no fan
This machine started life as a anycubic mega pro now it runs klipper and is direct drive
Cool machine!
I think you might be able to go a bit smoother. I did a few parts in TPU that came out pretty smooth, I’ll post a couple pictures below for reference.
I print TPU at 10-15mm/s speed with 10% fan and 0.1mm retraction. I find I have to reallllly slow it down to improve quality with TPU.
The top bit is TPU, bottom is PLA.
What kind of temperatures are you running.
I was printing at 230/80 +5deg each first layer
I’m only at 215C/60C, almost the same as my PLA temps.
I ran a temperature tower and found this temp worked best for that machine.
On my other machine I run 230C/70C for TPU with no retraction, each machine and roll can vary quite a bit.
I’ll have to give a temp tower a try, these were the first two things I printed after the direct drive mod.
They were more of a test to see if the new extruder setup worked since i couldn’t get it to print with the the bowden setup.
Looks like your off to a strong start, they look decent for fast rough first parts.
Now for the fun part, lots of trail and error through calibration lol 
I forgot to scale the doorstop for the reprint lol
these two towers we’re back to back not sure why such a drastic change, but it’s printing much better now.
Those reprints look much better! Much more dialed in it seems. I’ve never been able to fully get rid of the stringing with TPU.
Are you running lower temps and speeds now?
From the temp tower I would probably stick to the 200C +/-5C for your spool (as long as there is no clogging or skipping). It looks like that spool loses detail and finish at temps >215C to me, but test and tune yourself for sure!
I love seeing others use TPU and TPE, a doorstop seems like a good use case. I’m finding all sorts of odd uses for it nowadays.
The only thing that i changed was the temperature to 205, 190 didn’t extrude even though i thought it looked the best
I wasn’t sure what I needed to make out of tpu yet so I figured a door stop was a good test and still useful after
I printed a belt that i use everyday, so far its been going on 6+ months and no issues. I have also printed a bunch of fidget cubes which are fun. O havent tried it yet but saw a tpu printed flex coupler for a leadscrew on thibgiverse.
Though its not house branded, (sainsmart i think) and ive just been useing the stock prisa mini settings for my prints. I did have to free up each link, but didnt have too much stringing on it externally.
