1. Got a question or need help troubleshooting? Post to the troubleshooting forum or Search the forums!

Nylon Jamming in R2

Discussion in 'Troubleshooting' started by Sparky, May 19, 2019.

  1. Sparky

    Sparky New Member

    Joined:
    Oct 1, 2016
    Messages:
    2
    Likes Received:
    1
    I've been printing lots of PETG and ABS on an R2 for several months with no problems. Over the past few days, I've been trying to print with Kodak Nylon 6 (Natural). I can make small prints with no problems, but when I try to do something large that takes several hours I invariably get a jam that usually ruins the print. I've experimented with temperatures from 235 to 280 and got jams at all of them. I tried printing at half speed (30mm/s) and seemed to get jams even faster. I can clear these jams by pausing, pulling the filament out, chopping off the part that's kinked up, and reloading it. I give it a little push to get some plastic running out of the nozzle and can resume printing - as long as I caught the jam soon enough. Here's a photo of several of the remnants that I've pulled out of the extruder:

    2019-05-19 20.47.31-1-r1.jpg

    I've only had one jam where I had to take the nozzle off and clean things out, and that may have simply been due to getting hot plastic into the cold break and having it freeze in there.

    Nylon 6 is a fairly soft filament compared to PLA, ABS, and PETG. From the photos above I'm guessing that the filament may be binding and kinking in the tube that runs through the X-Y bearing block between the drive and the hotend. I had similar problems running TPU, but was able to overcome them by running a little hotter and a little slower. Maybe that section needs a tighter PTFE sleeve in it (I haven't looked in there to see how it's built, so just guessing.) Or maybe Kodak Nylon 6 is an overly soft filament and there's something else someone could recommend.

    By the way, I'm printing fairly large duct-like components (100 mm diameter) that have to retain their strength with 100 degree C air flowing through them. That's what has driven me to try Nylon.

    Any suggestions would be appreciated
     
  2. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
    Staff Member

    Joined:
    Feb 18, 2015
    Messages:
    5,806
    Likes Received:
    3,521
    Slower and hotter might also be the ticket for Nylon on the R2. Personally I have never printed nylon on the R2 / C2. The other thing to do is try a new nozzle or at least season the nozzle, like PLA nylon is very sticky when hot and doesn't flow well. Usually is sticks to itself, but any impurities in the hotend path may also contribute to sticking.
     
    mark tomlinson likes this.
  3. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
    Staff Member

    Joined:
    Feb 21, 2013
    Messages:
    21,134
    Likes Received:
    6,997
    @WheresWaldo is correct -- slow and hot is the general rule for nylon.
     
  4. Sparky

    Sparky New Member

    Joined:
    Oct 1, 2016
    Messages:
    2
    Likes Received:
    1
    It's been a while, but I wanted to close this off and relay my results. First of all, thanks to both of you for your suggestions. My problem turned out to be several simultaneous problems. They were:
    • Partially clogged nozzle - I opened it up and cleaned it out thoroughly.
    • Waterlogged nylon - The stuff came in a vacuum sealed bag but still had water in it. I now dry all nylon at 85C for a few hours before putting it on the printer. I keep the filament in a sealed sterilite bin with an Eva-Dry desiccant unit. I oven dry nylon that has been out for more than 24 hours.
    • Too much retraction? - I moved the retraction setting down to 4mm from 8mm in Cura (4.0.0). Could be that it was pulling melted nylon too far up into the heatbreak and it was sticking up there. I also wonder if wet nylon causes steam bubbles inside the head during retraction. That might cause weird things to happen, like blowing little bits of nylon up into the cool parts of the head.
    • Seasoned the nozzle - Followed the recommendation to season the nozzle - something that generates lots of heated religious debate online. Looked at the many methods online and went with simply putting a drop of avocado oil on a paper towel and rubbing it into about a foot of filament and running it through. Nylon seems to soak this oil up and it does not collect on the surface, nor does it appear to leave residue on the drive components. I do this once about every 300 grams of filament (several hours of printing) and I do it when printing the second layer of a raft to keep it from affecting the actual part.
    So now I've run several kilos of Nylon 6 through the R2 with no problems. I'm able to run this stuff at 60mm/sec at 245C with no cooling, 60C bed. I'm printing on BuildTak on a Flexplate with Elmer's Washable school glue stick. No adhesion issues, but the stuff I'm printing is fairly low profile so there's not much force to pull up the corners. I do have to use a raft or brim. Thinking about getting a sheet of phenolic paper (Matterhackers calls this "Garolite") and sticking it to a flex plate for some larger work that I have coming up. Don't know how much more development I'll do on this machine as Robo seems to have gone off the cliff.

    Thanks for your help.
     
    mark tomlinson likes this.
  5. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
    Staff Member

    Joined:
    Feb 21, 2013
    Messages:
    21,134
    Likes Received:
    6,997

    Yea, Nylon is a pain when it comes to humidity or "wet" filament. Still my favorite to use :)

    I now keep a dehumidifier running in the printer shop and keep the humidity at 40% (or less) all the time.


    Excellent work and thanks for following up!
     

Share This Page