TPU printing on the Longer LK5 Pro SOLVED
Making this post to hopefully help anyone who stumbles upon this same problem I had. I had a large size model to print in TPU so I needed the bigger build area from my Longer LK5. However it was not as simple as I thought. After tweaking my settings to the point where I shouldn't have been experiencing errors (disabling retraction, dropping print speed, raising temps, etc.), I moved my focus to the extruder itself. The extruder assembly is a bit different from the Ender's that I'm sure many (including myself) are used to. Where Ender's have a screw you can use to add or remove tension from the spring, the LK5 does not have this adjustability. With no room to adjust this tension on the part of the extruder that grabs the filament, this can cause jams such as this (https://imgur.com/a/rnHtbF1) [example shown on a different printer] I've also seen the filament jam underneath the brass gear causing some difficult jams to undo. After struggling with this I eventually came upon a very simple solution. You have to take the top part of the extruder apart, only need to remove one screw (https://imgur.com/a/vfFUMiD) careful not to shoot the spring across the room when removing. Then you'll just need one small washer (https://imgur.com/a/XPHhaHi) that will fit around this little post where the spring sits (https://imgur.com/a/x2bVD81) This small adjustment will remove a small amount of the tension while still feeding the TPU at a consistent rate. I have not had any jams or failures while using TPU since doing this. I would remove this modification when swapping to a different type of filament, I have not tried feeding any stiffer filaments with it but I imagine they would not feed correctly.