Pulse + Cura + TPU=????



  • Does anyone have any good settings for Cura and TPU's (Ninjaflex)? When I explore settings online, I constantly see sites saying that speeds should be around 30mm/sec. If I print at that speed I end up with a bunch of tiny balls somewhat connected with a tiny line. I am finding that I have to print around 10mm/sec to even have a shot.

    I've tried increasing the flow rate to 130-150% to try and get more to lay down and I'm still getting a really bad initial layer as well as the following 2 or 3 layers before the print starts to look good. Any help would be appreciated.

    thanks


  • Global Moderator

    Hey @dirtbikes987

    Alright, so I always have a comment on all things flexible related when people ask. The main point to remember is with Flex materials we are fighting pressure. Pressure is being generated in the hotend and extruder of the printer and here is how.

    Print speed, Nozzle temp, and Nozzle diameter are the three points to keep track of. Running flex is a bit of a juggling game with these three.

    You have to print slow and you have to keep that nozzle hot and the diameter at .4 or higher if you can.

    So lets take for instance that yo are running the filament at 260c and at 20 mm/s and you are still getting issues. the next thing to try would be to change the nozzle diameter up. (really unlikely for most materials but this is a hypothetical so yeah).

    What you have mentioned here is a bit of an issue, you increased the flow rate which is another way of increasing the print speed (extrusion speed per mm). This is really counter productive to what you need here. Lets drop the speed back to normal rates and run the nozzle temp up some. From there lets get some pictures of what is going on and setting profiles maybe?

    We do not really use Cura here so my ability to assist you is going to be a bit limited but I will give it a shot.



  • Michael, thanks for the reply. I'll put some flex in the printer sometime in the next couple of days and take a picture of the first layer. I have measured my build plate with an indicator and I know that I'm out about .020" from one side to the other. I'm not running auto level in Cura (I don't know how so if someone does, please help there too) so I know that isn't helping matters either. I plan on shimming my bed to fix that issue but I know that isn't the only problem that I have. I print NylonX no problem, parts come out great (I would have to say somewhat comparable to the prints that we get at work on our Markforged printer so I am content on my NylonX prints). So, given that NylonX is good and TPU is bad, I have to assume that I have some setting issues. I'll get a list of my settings to in my next post.


  • Global Moderator

    AH HA!

    There is a point I did not see, you may have been running a much higher temp material through the system before the flex. This may cause some high temp material to still be in the nozzle while trying to extrude the lower temp Ninjaflex. Just a bit of material stuck in the system will cause you a lot of issues. Run the Ninjaflex or other PLA at 250 for a short period (load for a bit) then drop the temp and extrude again. You want to be stepping the temp down and getting only low temp material loaded up in the hotend.



  • Michael,
    Attached are my cura settings for Ninjaflex for reference. Like an idiot, I modified two things and now my print looks awesome; so I don't know what fixed it.

    First, I mechanically leveled my bed (added shims underneath). I was out close to .040" and now I have it within .005" in most areas, .010" at the worst.

    Secondly, I did what you suggested. I did a load material through Mattercontrol. I said I was loading Nylon X even though it was Ninjaflex so I had the nozzle up to 260 and I just let it ooze out until Mattercontrol turned it off.

    So, I'll give credit to both. I'm assuming leveling helped and who knows, maybe I had some Nylon X plugging up the nozzle a little bit

    Once my print is finished, I'll start playing with speeds to see if I can go any faster.

    I won't consider this issue resolved or closed but in the monitoring stage.

    thanks

    0_1548287844024_ninja.png )


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