TPU on MMU3  

RE: TPU on MMU3

Hi Philip - 

I haven't printed with it myself, but I think you can create a TPU filament entry by adding a new filament, edit all the paramters, and selecting the type "FLEX" in the advanced section of the Filament Settings. 

Thomas

RE: TPU on MMU3

I've done that. But I don't understand the reason why. There are more materials they are not supported. And you have to create every single one. And it could be so easy. 

RE: TPU on MMU3

I have turned off the MMU in the settings menu and then just fed the TPU directly into the extruder using the standard (non-MMU3) profile.

RE: TPU on MMU3

Thank you! But that's not what I want. I want to mix different materials TPU included. 

I printed a rim with the tire around in one step. The rim is PETG and the tire TPU. 

RE: TPU on MMU3

I created a TPU profile for the MK4 / MMU3 (copy all data from a MK3 profile). I had to change the filament sensor back to the original solution (spring loaded ball) because the soft TPU did not move the lever enough to trigger the sensor.
I was able to print a PLA / TPU mix. It was not reliable Unloading of the TPU creates sometimes mess in the nextruder, which could be caused by the ramming sequence. Also the extrusion volume is not good enough which might created by the tension of the TPU caused by the MMU and the long tubes.
Needs definitely more optimization - but right now I do have other priorities.

RE: TPU on MMU3

Posted by: @zwirbel

I have turned off the MMU in the settings menu and then just fed the TPU directly into the extruder using the standard (non-MMU3) profile.

I assume you are leaving the MMU3 mounted? If so, how are you placing the TPU filament spool to enable a direct feed to the extruder?

Thank you! But that's not what I want. I want to mix different materials TPU included.

I printed a rim with the tire around in one step. The rim is PETG and the tire TPU.

Due to the push-pull process of loading filament flexible materials are problematic, I assume this is why they are not officially supported for the MMUs.

Whilst it *has* been done, regard it as no more than a party trick.  For practical purposes TPU and hard filaments cannot easily be printed together with any of the MMUs.

Luckily the QL does this well so there is a way - just not with any Mk3/4 + MMU2/3 combination.

Cheerio,

RE: TPU on MMU3

Hey guys,

I wanted to add my experience here before opening a separate Issue with Prusa, as this might be relevant for you as well:

Did any of you experience the issue, that the new Nextruder Filament Sensor Assembly on Mk4 with MMU3 does not recognize flexible filament?

Apparently it jus doesn't trigger the sensor, because it does not have enough tension to sufficiently move the idler to the side, which is what the new sensor detects. I tried recalibrating it, but calibration fails, as the idler is not moving enough and the printer doesn't detect filament.

RE: TPU on MMU3

Posted by: @ralf711

Did any of you experience the issue, that the new Nextruder Filament Sensor Assembly on Mk4 with MMU3 does not recognize flexible filament?

I did and I came to the same conclusion. But my MMU can't push flexibles all the way into the extruder anyway, so it doesn't really matter.

RE: TPU on MMU3

I recently received my MMU3 for the MK4 but haven't installed it yet so excuse me if this is a stupid question.  I hear a lot about bypassing the MMU when feeding TPU.  Besides disabling it in the setting screen, are you disconnecting the Bowden tube above the filament sensor or some other way.  I want to still be able to use TPU after I get the MMU3 installed, so just looking for ideas.

Thank you.

RE:

My setup has the MMU unit still centered and I have a Mk4 spool holder and filament guide to one side. I have a magnetic release PTFE connector in the tube between the MMU and Nextruder which allows a direct feed from the top spool holder without the need to remove the PTFE tube from the Festo fittings.  Here's what I used:

https://www.printables.com/model/581332-spool-holder-for-original-prusa-mk4

https://www.printables.com/model/30599-filament-guide

https://www.printables.com/model/873440-magneticslotted-ptfe-rotating-disconnect

It works well. 

RE: TPU on MMU3

To ensure you: yes, you will still be able to print TPU no problem, you just have to de-activate the filament sensor. Otherwise when loading, it feeds and feeds and feeds because it doesn't detect the filament, until it is all tangled up in the main gear, at least that is what happend to me.

Dsconnect the hose as described and feed straight to the Nextruder. I myself do not even use a double coupling, I just release the tube from the coupling at the nextruder and feed straight through it.

The only thing that changes is, that loading doesn't auto start with the sensor deactivated.

RE: TPU on MMU3

I do not agree! You just loose the screws on the nextruder a bit, and the sensor works just fine. 

An you can go through the MMU also.