Printing Flex: TPE32
Hi,
I went for the adventure of printing flexible filament. I have TPE32 from Filament PM, which is on the harder side of the scale.
What parameters do you suggest to tune?
I use 0.4 nonHF nozzle, I reduced tension of the idler. In slicer, I started from the profile publish by the same company for softer filament. Reduced volumetric flow to 2mm^3/s. I print on PP tape, no bed heating.
At one point of the print I got sticker filament warning. I attempted to reload the filament, but unload failed. I found the filament folded between the extruder gear and housing. I had to disassemble the head.
Since the filament location, I attributed the problem to retraction. Set it to zero, tried again.
This time the print completed, meaning it reached 100% counter. However, the extrusion stopped at the same point of the model, probably with slipping extruder gear. When I was unloading, I pulled on the filament, but probably too little, as it got jammed in the same exact location. I had no problem to pull the filament from the nozzle and put of the filament sensor, but to clear the jam, I'll need to disassemble again.
So, any ideas what to tune next?
RE: Printing Flex: TPE32
Hello, I also ventured into using flexible filament, although I bought a softer type. I read that the AmazonBasic TPU setting is supposed to be quite good for the MK4S.
I turned off the fan, and the nozzle temperature ranged from 240 to 255 degrees Celsius (this is supposed to be about 5 degrees higher than the manufacturer's recommendation).
The filament is initially fed in properly. I can also continue cleaning the nozzle without any problems.
After my MK4S leveled the print bed, it tries to start printing, but it can no longer feed any filament. A knot has formed in the extruder (see photo).
When I remove the filament from the extruder, the nozzle isn't clogged.
What's going on? Is the extruder feeding in too much filament? If so, how can I prevent this?
RE: Printing Flex: TPE32
You could try using the main plate from this project: https://www.printables.com/model/1320158-iaf-idler-11-for-prusa-nextruder-with-mmu-unleash
This main plate has a filament path that is more constrained at the sides and gives less space for flexibles to move to the side and curl up.
I also had the same problem with TPU/TPE stalling in the Nextruder after bed levelling when I used the existing FLEX filament type to load the filament on the printer, which has a nozzle temp of 240 °C. I had better success loading flexible filaments either with existing PLA type (220 °C) or with creating my own TPU/TPE user profiles on the printer that use 220 °C nozzle temp as well. I had good success with this for SainSmart TPU95, Fiberlogy Fiberflex 40D, and Polymaker Polyflex TPU/95.
RE: Printing Flex: TPE32
I have some updates.
I think, I was still too much ignoring Flexible rule no.1: Print very slow.
The default volumetic flow of the profile I use is 3 mm<sup>3</sup>/s, which still leads to speeds up to 60mm/s. When I reduced speed to 50%, it was fine(ish), there formed slow build up close to the gear (I could hear extruder clicking). Temporarily fixed by "reloading" the filament.
With the "reloading", I mean open the Idler, cut the filament at the inlet side, and use the pliers to pull the filament out of the nozzle.
Next round, I am setting the flow down to 1 mm<sup>3</sup>/s, that is maxing the speeds to 20mm/s.
RE: Printing Flex: TPE32
Yes, I'm otherwise very happy with my MK4S. But I'm not happy that I now have to update the extruder to print TPU. I don't use an MMU and I'm not sure which files I need to print and replace. Could someone perhaps offer some assistance? I've been involved with 3D printing for almost two years, but I'm still a beginner.
Besides, this is taking up a lot of my time again.
Many thanks for your help.
RE:
You don't have to print your own main plate to print TPU/TPE with your MK4S. I was able to print those on my MK4(S) before I modified it for the MMU3. Just loading TPU/TPE with 220 °C nozzle temperature was enough to get it to print. Loading the flexible filaments that I have used so far with the FLEX profile on the printer (at 240 °C!) almost always resulted in a clogged nozzle at the start of the actual print. Loading the filament at 220 °C worked.
But if you want to experiment with the modified main plate, there is also a version for non-MMU printers: https://www.printables.com/model/1332821-iaf-idler-11-for-prusa-nextruder-nommu-unleash-the/files
The main plate comes in 4 versions. "newGear" refers to the Nextruder on the CoreOne, "oldGear" refers to the one on the MK4(S). And there also are versions with and without LCP (load cell protection). This is an elongated shape that goes under the planetary gear, I guess to prevent a piece of tangled filament from getting in there and pressing on the load cell. Just compare the two versions of the file in the 3D viewer to see the difference in shape.
Changing the main plate on the printer is not difficult if you are careful and keep the gears inside the brass ring. You can just open the idler lever, remove the 3 screws and pull the cover and the brass part off, exchange the main plate and put the gears back in. I have done this several times without needing the gear alignment jig. Just work slowly and carefully with good lighting. After you are finished do the planetary gear calibration.
RE: Printing Flex: TPE32
Hi, I really appreciate the support here.
For one component, I have to repeatedly print an STL file with TPU. This adds up to 15 hours of printing time in total. Therefore, I'll print the updates for the Nextrudder first. Hopefully, this will prevent any problems during the TPU printing process.
Thank you for the quick replies.
RE: Printing Flex: TPE32
If printing several TPU/TPE parts in a row I sometimes had the nozzle clog on the second one. So I always unload the filament after a print and re-load it again before starting the next print job. This seems to prevent the clogging on the following print. The reason is probably the changing nozzle temperature from after finishing the print to bed levelling and then to starting the print. Flexibles seem to be more sensitive to these changes than other filament types.