Welcome to aurora.com! Log in or Sign up to interact with the aurora community.

Bulldog XL + 2 Hotends Not Working

Discussion in 'Bulldog Extruder' started by jaime valencia, Jan 7, 2014.

  1. jaime valencia

    jaime valencia New Member

    Joined:
    Dec 26, 2013
    hi I got [ $213 Bulldog XL + 2 Hotends}i try to put the filament 1.75mm and it getting stuck I looking for instructions videos something on how to use this product but no luck. i was wondering if some one have instructions for a beginners step by step on on how to use it.
     
  2. Impact

    Impact New Member

    Joined:
    Jan 6, 2014
    Location:
    Germany
    Hi, i had difficulties at first, too. The springs, pressing the roller to the filament gear are extremely strong. These springs you have to press against, when you insert the filament. Test it, when the extruder isn't mounted. You can release the spring tension by turning the 2 grub screws. Remember to tighten them after inserting the filament. Finally i had to change the data in Marlin, that defines the turning direction of the extruder.
     
  3. DoomStrike

    DoomStrike New Member

    Joined:
    Jul 1, 2013
    I went from using a non-bulldog extruder with a Jhead hotend to a bulldog extruder using a merlin hotend.

    I am having a hard time getting the bulldog to print properly. I just found out that my filament gets stuck in the merlin hotend if I feed it too much at a time. My filament is 3mm and I'm using the 0.50mm nozzle. Out of curiosity which hotend are you using and with what nozzle size?
     
  4. Impact

    Impact New Member

    Joined:
    Jan 6, 2014
    Location:
    Germany
    I am using the Merlin hotend with 1,75 filament and a 0.4 nozzle.
    Test the unmounted hot end without nozzle by pushing a piece of filament all the way through. Does it appear at the end, without jolting inside? Try to tighten the 2 grub screws that are connected to 2 springs, pressing the hobbed gear against the filament (after inserting the filament with untightened springs, i found it way too hard to release).
    Stupid question: Is your hot end hot (enough)?
     
  5. DoomStrike

    DoomStrike New Member

    Joined:
    Jul 1, 2013
    Impact, you wrote "Merlin hotend with 1,75 filament and a 0.4 nozzle", this was not a standard package. Did you mean 0.5mm nozzle or are you using the magma hotend that came at 0.4mm nozzle size. I am pulling the packages form the indiego campaign http://www.indiegogo.com/projects/bulldog-extruder-project
     
  6. Impact

    Impact New Member

    Joined:
    Jan 6, 2014
    Location:
    Germany
    Good question. I got an All-Inclusive-Package with the OrdBot, RUMBA, Bulldog and Hotend. I am pretty sure its the Merlin. Included was a little bag with 3 different (airbrush-)nozzles. Inspecting them with a watchmaker magnifier I guessed its 0.3, 0.4 and 0.5. I took the middle one, machined myself a tiny wrench and put it on the Hotend. I calibrated the Printer assuming a 0.4 nozzle and the result (after some formula tweaking in Marlin) was an exact 20 by 20 mm cube with 0.5 walls like this one
     
  7. DoomStrike

    DoomStrike New Member

    Joined:
    Jul 1, 2013
    Hmm odd, the merlin hotends should be 0.2, 0.3, and 0.5mm unless the indigo page is wrong.
     
  8. Impact

    Impact New Member

    Joined:
    Jan 6, 2014
    Location:
    Germany
    This might still be a possibility. The current RRD shop offer states these 3 nozzles (0.2, 0.3 and 0.5), too. I will do some more Marlin and Pronterface tweaking and double checking the results with my caliper.
    Thanks for the headsup
     
  9. DoomStrike

    DoomStrike New Member

    Joined:
    Jul 1, 2013
    I finally had some time to do some testing by changing out one component at a time. After a few tests it seems that the merlin hotend can only work if you're using a very low speed for it. The speed for myself is a bit too slow since my larger prints would take well over a day. If you don't have an alternative hotend, print at lower speeds and you should get good quality prints out.
     
  10. Impact

    Impact New Member

    Joined:
    Jan 6, 2014
    Location:
    Germany
    Hi DoomStrike, nooo, this sounds like you are giving up? Did you calibrat the Extruder and Printer as explained -->here or at any of the other places?
    Specify "speed too low". I think the print speed is limited mostly by the moving mechanical parts, not the Hotend (i might be wrong here, still a beginner, too).
    I think the few test prints i did went well with between 30 and 60mm/s (even with a wrong value for the nozzle diameter calculation).

    I finally measured my nozzles and they are 0.25 (meant to be 0.2, i think), 0.3 (attached to my Hotend) and 0.5. I will do the calibration again, with the new nozzle diameter inserted at the certain fields in Slicer/Pronterface.
    I think, even with close to perfect 20x20x10 / 0.5 thin wall calibration cubes i am only at the beginning of the calibration process.

    Don't give up, try harder
     
  11. DoomStrike

    DoomStrike New Member

    Joined:
    Jul 1, 2013
    Hey Impact,

    Here is what I did, I used default speeds from slicer. I ran it on the bulldog with the merlin hotend. I found that the default speeds were too high for the merlin. Keeping everything the same, I changed out the merlin hotend with that of my previous hotend (prior to bulldog purchase); after the change I was able to print my model without any issues.

    Looking back on the models I tried to print on different speeds, the only good print i have had was a small hollow octupus at 15mm/s. This is because all my perimeters were "small perimeters" which is at 15mm/s in slicer. It had no fill, but on the models that did require fill the speed is 60mm/s on slicer-- this is what alerted me to something being wrong.

    I haven't tested what the upper limit is for the merlin in terms of speed, temps, and diameter of the nozzle. At the only "good" speed I found as mentioned above a large print object that almost utilizes my whole print bed (200mm x 200mm x 180mm) would take over two days to complete! I don't have the patience to find what the actual limits are on the Merlin. I already spend too many weekends on trying to make the merlin work, but in the end the best solution for me was to go back to my Jhead.

    Also I did try increasing the temperate to see if that would help, I went from 200C to 240C and the merlin was still not able to keep up. Even worse, the prints turned out bad due to "oozes" from such high temps. The oozes would happen on the perimeters and not during infill (which is double the speed on my settings). Even than the infill was still not good and would miss spots due to a lack of constant extrusion.
     
  12. Jeremy Bernal

    Jeremy Bernal New Member

    Joined:
    Mar 22, 2013
    I have to say that I am disappointed with the Merlin and Magma hot ends as well. I have had the same exact issues. First, I thought it was temperature, since the default 100k thermistor settings were not showing accurate temperature (they indicated higher temp than reality), but once I got them calibrated, using a calibrated external thermometer, I still had the same jam problems. I couldn't even run plastic through at 250C. Just jams up and then the extruder eats up the filament.
    I've had years of nonstop excellent results without jams using an Airwolf Buda hot end, so I'm going to have to make a mod part to use that with the Bulldog.
     

Share This Page