Hemera tpu issues

Discussion in 'HotEnds & Extruders' started by Chainbreaker2012, Jan 13, 2020.

  1. Daniel Rock

    Daniel Rock Well-Known Member
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    I have been doing some testing with various TPU's, in general, increasing the temperature is the solution.
     
  2. Danny Baughan

    Danny Baughan Member

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    Been up to 260 and it wasn't the solution for me.
     
  3. Cwood

    Cwood Member

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    Yep, i thought temperature was the fix and it wasnt. At 250 most TPUs come out burnt and ugly. i've tried just about every setting combination possible and it just wont print flexibles at ANY speed or temp. My stock ender3 pro printed more reliably and ive torn it apart to install the hemera.

    There has to be some common cause for those of us having problems and those that are printing sucessfully. E3D needs to be accountable for the claims made about this product. If E3D didnt advertise this as an extruder good at flexibles I wouldnt have bought it. Did E3D do any testing to validate the flexible claims or was it just a theory thing?

    The only thing i can figure is the tolerances on the gearing isnt tight enough, I think they wiggle and cause jams. As you can see in my attached picture it doesnt look like the filament gear lines up right with the hot end. Also what the heck is that red gunk on the drive gear? Is that rust?
     

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  4. Cwood

    Cwood Member

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    Even though my filament is only a couple weeks old I tried running it in the oven at 140 for a few hours. Nope no effect. Still jams.
     
  5. Daniel Rock

    Daniel Rock Well-Known Member
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    Danny and Cwood, I have been printing different TPU brands and hardnesses(with slightly different temperatures, but all based on the Prusa PLA profile) In the effort to try and troubleshoot why you are having these issues. Aside from some cooling issues on the front bow all have been able to be printed successfully, Sainsmart TPU(215), Ninjaflex(250), and Spoolworks FleXD(215).

    I would suggest opening a support ticket with support@e3d-online.com and explaining the issues you are having, it may well be the case that you have units with the faulty gears and a replacement set would get you printing more reliably.

    I am still running some more tests in order to get a table of recommended settings for different TPU hardnesses and will share shortly.
     

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  6. Thorinair

    Thorinair Well-Known Member

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    The E3D claims about printing TPU well are valid. I have been printing with spoolWorks FleXD at 220C without any problems, but I did have to go slower. Not because it was clogging, but because overhangs didn't come out as good.
     
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  7. Daniel Rock

    Daniel Rock Well-Known Member
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    Yeah, overhangs are an issue. As you print faster the part cooling needs to also increase TPU's tend to warp quite a bit if they aren't cooled quickly enough. So you may find that you need to print TPU's slower to accommodate for this, not because the extruder isn't able to cope with it but due to the material properties.

    Thorinair's duct is what I would consider one of the better designs out there at the moment I'm trying to find the link but Thingiverse is being a pain at the moment.
     
  8. Thorinair

    Thorinair Well-Known Member

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  9. Bruce Jenkins

    Bruce Jenkins New Member

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    So... I'm going to throw my 2 cents worth in here ....

    I have upgraded 2 machines to the Hemera - Tevo Tornado, and my Ender 3. Went from BMG Bontech (type) extruder on both to the Hemera - wanting even 'better' flexibles printing.

    Initially, some prints went ok - but I was having the same issue as some of the others here - that, after getting into the print for awhile, they would jam.

    So - I decided to to some testing based on this and other 'tpu issue' threads.

    I typically print my SainSmart TPU at 220c (and btw, I've found SainSmart to be one of my best TPU filaments).
    When simply 'extruding' the tpu at that temp... it would feed just fine ... no jams, very smooth. However, when I would be 'back pressure' on the nozzle (using a spatula) to mimic the nozzle on the bed ... after ~50mm the filament would slow and then stop feeding. Removing the spatula (pressure) - the filament still would not feed.

    Pulling the filament out of the extruder showed that it had jammed 25mm from the hotend - sometimes with a 'kink' in the filament - and very interestingly - the filament had 'expanded' from 1.75mm to 1.80-1.90+ inside the heat-break. So- I could tell that there was no way for the filament to get through the heat-break and into the nozzle again.

    This was telling me - that either I had to much tension feeding the filament - or, my nozzle wasn't hot enough for the filament to flow. Backing off the tension didn't help.

    I was about to take off my regular heater-block and put on a volcano, but instead tried increasing the temp first - even though other's here had no luck with uping the temp.

    BTW -- both Hemeras on both printers demonstrated the exact same results.

    For me ... going to 230c was the trick. At 230c on both printers I am able to print without jamming (for now) .... After the temp increase - I also 'backed off' the tension - though that doesn't seem to matter much for this filament.

    I have yet to test softer flexibles e.g. NinjaTek, etc.

    I've posted some photos of the filament as well..... don't know if this will help anyone ...
    IMG_20200217_172452 (Small).jpg IMG_20200217_172612 (Small).jpg
     

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  10. Chris123456

    Chris123456 New Member

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    Have the same issues (ref pictures). Tried different temps, tensions, nozzles, etc. but no change. E3d did mess up big time with the Hemera in my opinion. If somebody has any solution I would be really thankful to hear about it.
     

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  11. Chainbreaker2012

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    ok, been out of town on business so havent been able to update lately. here is what I have found so far. I am using a copper volcano block with brass nozzles and nozzlex nozzles .4 and .6 60w heater, all firmware adjustments made. Tronxy tpu temp range from 190-230 currently newer roll 4 days old. still dame issue unless I go up to 245 to 250 but then it is boiling and dripping from the nozzle still catches and binds up. this isnt a heat issue. I think the issue is the heatbreak and the way it comes up to the hobbs. I have been pulling the extruder apart when it does this with the filament clipped in it and it is mushroomed at the top of the HB. the temperature never fluctuates when it cloggs up. going to try taking some lapping compound and lapping it up top at 30° and then polishing it to see if I can get it to work. but it may be a few days before i get a chance to do this.
     
  12. VladimirK

    VladimirK Member

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    Maybe it is heatbreak, those metal tube do not looks good for me. I'm still on Aero with titanium heatbreak from Trianglelabs (full metal, without PTFE), Volcano. No oiling or something special. For me the trick to print Flex, that even unable to go through PTFE tube without sticking, was to soften tension (filament was bending even at small distance after gears), no retraction and small print speed 20mm (as recommended for Flex).
     
  13. Dory

    Dory Member

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    I wish I would have caught this thread before as I bought this to upgrade the titan clone on my Sidewinder and for flexibles. Using my artillery sidewinder SX-1 I'm jamming just as everyone else has demonstrated regardless of tension with fairly good success with PLA. I have tried changing print speed 35mm/s , increasing layer height from .1 to .15mm to let off some of the back pressure, I still get same kink about 20mm from the nozzle tip after being pulled free. One thing I have noticed is overall filament spool tension, if you have a lot of slack in the filament the print will go relatively well. Bad thing is who wants to babysit a long print?

    [​IMG]
     
  14. Dory

    Dory Member

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    Okay update - I found taking all the tension off the spool/filament feed into the hotend helps tremendously with preventing the jams/kinks with TPU. I've been printing almost 3 hours with no issues which last print I had several issues with jamming.

    [​IMG]
     
  15. BennoDXB

    BennoDXB Member

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    This is exactly what happens to me, just cant do ninjaflex without the gears clicking and the filament coming out kinked like in the other pics.Has anyone found a decent solution to this? winding off lengths of filament and greasing aren't really ideal in my opinion.
     
  16. TheAkashicTraveller

    TheAkashicTraveller New Member

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    Rust is a symptom of the known gear issue isn't it?
     
  17. SirFapsOlot

    SirFapsOlot New Member

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    I believe I have figured out what to do, at least for me this worked. Everything people have suggested here has been no good for my use. What finally worked was lowering my feed rate in my slicer. I currently have my settings at 90% feed rate and I can print at 30mm with no problems. Also, i have tension at 3 turns above no tension. This was tested with ninjaflex and eryone tpu. I have not had to make any changes like this when printing with denser brands that are more rigid.
     
  18. BatLord

    BatLord Member

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    Name the model of your printer, maybe its features will help you understand.
     

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