Trouble printing TPU on top of PETG
Hi
I have successfully printed an object, roughly 75 x 50 x 20 (X Y Z) with the top few millimeters (~1/8") using TPU. The rest is PETG. The TPU and PETG are interlocked together.
This worked very well indeed as a test piece.
When I increased the Y to around 150mm (ie 75 x 150 x 20 (X Y Z)), it takes much more time, obviously! I also upped the infill and walls, so print time went up quite a bit. From a little under 2 hours to nearly 10 hours.
The PETG section prints fine, but, the TPU is not printing at all. A small amount of TPU is getting wrapped into the extruder gear. This is not hard to clear.
While cleaning up, I have purged the TPU filament and what comes out is brown. The nozzle does not appear to be blocked.
My question is - is the TPU 'cooking' in the hot end while waiting to be used? Could this be causing enough of a blockage to prevent printing?
Is a possible solution, to adjust the temperature right down for the TPU while it is not being used? How?
Or print a small second object, of only TPU of near the same height? This would keep fresh TPU moving through the nozzle.
I'll start looking into these as possible solutions tonight.
If anyone has experience with this type of situation, I would much appreciate your comments.
Thank you
Philip
RE: Trouble printing TPU on top of PETG
Looks like the temp can be reduced, but, was already set to 70C when the TPU print head when parked, and yes, ooze prevention was on.
I'll try a small TPU print at the same time. Will slow things down even more. I hope to get this done next week.
Tonight, I'll run a simple TPU only print and see how it goes. Make sure the toolhead is working correctly.
Philip