Fun with TPU and PETG-Only On an XL!
I wanted to print a work mat for my workbench using clear TPU since it is soft and won't damage fragile parts. I also wanted it to contain small parts like screws so I wanted a wall around the mat.
I designed in OnShape a mat that also had a 1.2 mm sheet of PETG (in yellow below) in the middle to stiffen up the mat and test using TPU and PETG together.
I removed the side filament detectors from my XL so using TPU is a breeze now. See my post below on removing them. I highly recommend their removal.
My 1st print was ok but not perfect. There was some PETG that didn't stick to the TPU and some blobs. I did not use a purge tower since my initial mat covered the entire build plate. I initially printed the PETG at normal speeds (170mm/s) which was too fast.
I reduced the size of the mat to allow for a purge tower. I then slowed down the PETG speed to 90mm/s and also raised the extruder temp to 250c. I also played with infill patterns and chose a Hilbert curve in the PETG. I also added some text as a modifier in the PETG part in a different color. The top and bottom TPU surfaces were 0.4mm (2 layers) thick on top and bottom. I also adjusted the number of solid layers in Prusalicer to get at least 2 solid layers of PETG. So, this print took 3 different filaments (2 materials). 12 Hours later I had my perfect mat.
I am amazed at how good the mat looks and feels. Only a Prusa XL could make this print! I already have requests for custom printed mats from my friends. 
RE: Fun with TPU and PETG-Only On an XL!
Great print!
you should share it as model! 🙂 (Oké, maybe with a more generic text hah)
Don't forget to check out rnldnkp.com 😀
RE: Fun with TPU and PETG-Only On an XL!
Thanks for the suggestion. I have uploaded the 3mf to Printables:
https://www.printables.com/model/963982-tpu-and-petg-work-mat-with-walls-prusa-xl-5-tool-o
Please read the notes before modifying.
RE: Fun with TPU and PETG-Only On an XL!
What was the thought behind switching to Hilbert curve instead of the usual monotonic lines? Another way to slow down the PETG printing to help with adhesion? Help against warping? Does it make it more flexible?
XL-5T, MK3S MMU3 || GUIDE: How to print with multiple-nozzlesizes do read updated replies || PrusaSlicer Fork with multi-nozzlesize freedom || How Feasible is Printing PETG for PLA supports on XL very
RE: Fun with TPU and PETG-Only On an XL!
I tried the Hilbert curve for the infill only (monotonic for the outer surfaces). My 1st print attempt showed the PETG infill pattern on the top TPU surfaces. However, I also added another solid layer in the top of the PETG on the next attempt which eliminated the infill pattern showing through, so there really was not any impact in the infill pattern switch. I had thought the spiral pattern would look cool.
I had no problem with adhesion. I used the textured build plate. The TPU really sticks well at 50C, maybe too well. Removal was hard to get the peel started but went easy after that.
RE: Fun with TPU and PETG-Only On an XL!
About removing the side filament detectors, would it be OK to thread the TPU so it doesn’t pass through the detector and simply insert a couple of inches of PLA filament offcut into the detector and leave them there, fooling the detector?
RE: Fun with TPU and PETG-Only On an XL!
Prusa has bypass "holder" for using flex filaments in xl, also in newer firmware version you can disable the side sensor individually.
https://www.printables.com/model/858033-flex-filament-bypass
OK to thread the TPU so it doesn’t pass through the detector and simply insert a couple of inches of PLA filament offcut into the detector and leave them there, fooling the detector?
Yes, or disable the sensor.
I generally bypass the delivery tubes and load Flexibles direct to the toolhead from overhead spool holders.
Cheerio,
RE: Fun with TPU and PETG-Only On an XL!
Just remove the side detectors. See my link at the beginning of this thread.
RE: Fun with TPU and PETG-Only On an XL!
Here is my Prusa XL filament loader (mainly for flexible TPU), using an electric screwdriver:
https://www.printables.com/model/978873-prusa-xl-fast-filament-ptfe-tube-loader-incl-tpu
Video:
RE: Fun with TPU and PETG-Only On an XL!
Very interesting! How does it do with other filament types? I guess I need to find some M3 square nuts. Did you try this with a M3 hex nut? I’m guessing it stripped out in the wheel?
RE: Fun with TPU and PETG-Only On an XL!
I guess I need to find some M3 square nuts.
Check your spare parts. 😉
You can also order them in the shop.
RE: Fun with TPU and PETG-Only On an XL!
- M3 square nuts 6x6x2 here
- I tried with other filaments, some of them slip if the tensioning screw is not very tight. But they are hard enough to be pushed by hand, so no need to use a loading device. TPU is very flexible and very difficult to push into PTFE tubes over long distances
RE: Fun with TPU and PETG-Only On an XL!
RO3,
Thanks for the link. I am thinking of trying your loaders in a Sunlu S4. I have 2 S4’s feeding my XL5 through Bowden tubes. Threading all 5 takes awhile so I thought this could speed things up but they would have to handle all materials. I’m wondering if the drive wheels could be printed with a TPU outer ring (only on an XL) to better drive the filament. What do you think?
RE: Fun with TPU and PETG-Only On an XL!
I tried it, but I need smaller bearings so I could make a thicker "tire".
RE:
OK to thread the TPU so it doesn’t pass through the detector and simply insert a couple of inches of PLA filament offcut into the detector and leave them there, fooling the detector?
I do, and it works just fine for me. (I have my TPE in a dry box on a shelf above the printer and run the dry box ptfe tube directly into the XL print head.)