After I reallised that I really need something for scratch marks for the wood I just bought the TPU from Suntop as well.
Before I start printing with the TPU, I have to make some upgrades for my Extruder with Teflon tubes inside. You will need it, otherwise if you print to fast the filament run of of the gear!!!
After I finish with upgrading I start with printing TPU at 40 mm/s and it was just the best speed. A little bit more would be possible, but if the filament to quick it cause to much blobs.
I also tested the retract function with the TPU from Suntop at 3 mm at 40mm/s and it working great!
No blobs or strining between the printing parts!
I still tested before some other TPU, but they are to hard to print with retraction, that because of the flexibility of the Filament. If there is to much you can not retract, that causes a lot of blobs in the printing objects and looks like a bad calibrated print.
I really can say that the Filaments from Suntop are one of the best Filaments I just even bought!!!