Filament changing (BigBox Pro 1.0)

Discussion in 'Calibration, Help, and Troubleshooting' started by Alex Stevenson, Apr 24, 2016.

  1. Alex Stevenson

    Alex Stevenson Well-Known Member

    Joined:
    Sep 4, 2015
    Messages:
    87
    Likes Received:
    14
    tldr; While I wait for filament to be delivered, I'd like to understand how to change filament and any tips to get more smoothly started in the printing, and any advice on maintenance, cleaning...

    I've finally completed the commissioning stage, and a couple of minor panics re the belt tensioning, all seems to have gone well.

    It may seem more than a little remiss, but at this point, I still don't have any actual reels of filament - only the samples sent. Naturally I want to print something as soon as I can do so, but I'd like to ask a couple of details that are missing from the build manual.

    When you get to the "Your first print" section, it only gives instructions using a reel of filament. I also read in the forums that using the loose filament can be problematic, as it's more likely to snag or jam in the printer. Should I be so concerned? There are other two reasons that make me hold back - that calibrating for such a small sample will be a bit wasteful, and secondly, that I will have to change the filament again before I've had a chance to get used to how it works.

    Are there any good resources / videos that explain how to change the filament (applicable to the BigBox)?

    I also, by mistake, ordered some Colorfabb PLA/PHA, which, in retrospect, seems to have mixed reviews, and also has different properties to PLA. I do really want to get used to PLA (I think) at first (and changing between filaments / types), before moving on, so I now asked to change that for the Premium E3D filament.

    Does anyone know any good videos / tutorials for these basics (including maintenance, cleaning, etc)?

    Sorry if I'm asking stupid questions - I feel so relieved that so far the printer progress is going well, and I want to keep that momentum going as smoothly as possible.

    Also, thanks to everyone who's given support and advice thus far. I couldn't have got this far without such an amazing community and fantastic support!

    IMG_20160423_195240.jpg IMG_20160423_195304.jpg
     
  2. Spoon Unit

    Spoon Unit Well-Known Member

    Joined:
    Sep 6, 2015
    Messages:
    1,095
    Likes Received:
    322
    There are a few answers here. YMMV with each.

    • @Alex9779 has a custom Marlin firmware which enables the LCD option to change filament. That would automate it I completely I guess. I've not tried it
    • I started with just running GCODE via Octoprint. G0 E-120 F200 should be a complete unload of the filament out of the top. On re-feed, push it as far as you can and you'll probably be able to just leave to print-start-priming from the S3D setup
    • I've settled on this now I feel comfortable with it all. Warm the nozzle to 210 say, hold the idler spring down, pull it out manually, refeed, push through until color change complete.
    The primary fly in the ointment for you will be the top of the bowden tube that leads from under the hobbed gear down to the heatsink. If you haven't beveled that entry way, you're going to feel like changing filament is a nightmare. I did notice in the Titan extruder, they pre-bevelled the entry way. You can do this with a craft knife easily. Maybe you already did.... Even getting the filament into that pipe can be a little bit of a challenge because the design is off by a mm or so, but I've become quite practiced at this now and I never have issues at all now. Filament change is about a 2 minute task for me now.
     
    Alex Stevenson likes this.
  3. Henry feldman

    Henry feldman Well-Known Member

    Joined:
    Sep 5, 2015
    Messages:
    969
    Likes Received:
    389
    Depending on how radical a switch, you often have to purge some filament out after switching (switching from black to white PLA takes a little purge, switch form PLA to ABS takes a lot more, or as I found out switching from PLA to Bluprint took almost 300mm of purging until it was pure and given the extreme difference in chemistry that was important...).
     
  4. Old_Tafr

    Old_Tafr Well-Known Member

    Joined:
    Mar 7, 2016
    Messages:
    560
    Likes Received:
    75
    Using one of the short lengths is a pain, I had another reel so I carefully wound it round this (full) reel and it worked ok. I tend to check its coming off the reel ok anyway.

    I too was confused/concerned that although I could find info on changing the filament there was nothing on the BigBox. This is simply that it seems like the technique is the same for most printers regardless, just go to YouTube and watch a few.

    Essentially the filament is melted in the heater block, but cooled in the heat sink immediately above so you have to heat the nozzle/block to melt it to then be able to remove it, then feed in your new filament. For interest you can mark it to see how much comes out.

    Once hot I used OctoPrint to pull the filament out, just use the Extract button on the Control menu. If you mark the new filament same as the old or against the side of the extruder you can see how far it should insert so you have an idea when the new is fully inserted.

    Keep the nozzle hot to allow the new filament to go as far into the hot end as possible.

    I found it a pain to hold the tensioner whilst I fed the new in so I braced my fingers below the X-Carriage front rod (upwards) so as not to apply too much force downwards on the X-Carriage rods. I also cut the new at an angle to assist its entry into the tube below the hobbed wheel. I also bent the filament straight so it would find the path more easily.

    PS Yes need to keep the nozzle hot and push filament through to purge the old. I used Octoprint to do this too.
     
    #4 Old_Tafr, Apr 24, 2016
    Last edited: Apr 24, 2016
  5. Alex Stevenson

    Alex Stevenson Well-Known Member

    Joined:
    Sep 4, 2015
    Messages:
    87
    Likes Received:
    14
    Thanks everyone.

    @Henry feldman as much as I'd love to switch and try different types, I do think I'll stick with PLA until I feel I've got the hang of things a bit; the more variables I change between prints, the less chance I'll have of working out what's gone wrong... that's the theory at least.

    @Spoon Unit I didn't know about bevelling the bowden tube, but I can imagine that it would be problematic if it doesn't match up. Hopefully the trick @Old_Tafr mentioned re cutting the filament at an angle will help though.

    Thanks again @Old_Tafr - you seem to have a knack of explaining things exactly in a way I can relate to / understand. I had checked a few youtubes, and wondered if the process might be similar, and, like you said, found nothing relating to BigBox specifically.

    So the concept (as I understand it) is to heat / extrude some of the old filament, pull it back out, and quickly push the new filament, I guess, hopefully into the original, still melted, filament, and begin extruding again...

    Is there a risk that the melted filament would cool and stick to the tube on the way back out? Does the "extract" option on the Octoprint reverse the extruder to pull it back for you?
     
  6. R Design

    R Design Well-Known Member

    Joined:
    Oct 7, 2015
    Messages:
    918
    Likes Received:
    183
    I think the idea is you soften the old filament without melting it properly.

    I go to 150C before pulling it out. That way no risk of a proper melt being sucked up into the heat break, there going hard and causing a blockage.

    Then you can heat some more (to the melting/extrusion temperature of the new filament) and insert the new filament. Just pushing down on it causes it to start coming out like toothpaste, cleaning out what's left of the old one.

    Really we should edit this into the Wiki as a part of a Bigbox manual. It's obvious to all these experienced and clever people, but like you I had to figure it out from youtube.
     
  7. Henry feldman

    Henry feldman Well-Known Member

    Joined:
    Sep 5, 2015
    Messages:
    969
    Likes Received:
    389
    Even without switching kinds, if you switch colors, you will want to purge some (hand or via g-code) unless you like some streaks of some other color in your print...
     
  8. Old_Tafr

    Old_Tafr Well-Known Member

    Joined:
    Mar 7, 2016
    Messages:
    560
    Likes Received:
    75
    I'm still learning too...........

    At some stage after heating you have to pull the old filament out, the filament should only be molten in the heater block, the "heatbreak" (the screwed bit between the block and the heat sink) is to keep the heat from melting the filament higher up (and them jamming where there isn't heat to completely melt it) and the fans come on at 40oC to keep this part cool.

    I suspect that as soon as you start to pull the filament out it cools sufficiently to not jam. You can't extrude filament as such if the hobbed wheel isn't being powered to push the filament downward, but the heat should allow some filament to seep out meaning there is also less to cool and clog when you pull the rest out.

    I doubt you can either extract or feed new filament quickly as the filament idlers spring is just too powerful to allow you to do anything quickly.

    You can use OctoPrint to either feed or extract the filament, obviously when the nozzle is up to temperature.

    As far as what temperature to use......... trial and error, maybe people who have done this lots of times will comment.
     
    Alex Stevenson likes this.
  9. Alex Stevenson

    Alex Stevenson Well-Known Member

    Joined:
    Sep 4, 2015
    Messages:
    87
    Likes Received:
    14
    Good point. I've got much to learn :)
     
  10. Henry feldman

    Henry feldman Well-Known Member

    Joined:
    Sep 5, 2015
    Messages:
    969
    Likes Received:
    389
    Once you done this once, it's easy. (well if you don't have a titan, it is easy-ish as the idler handle really is hard to press down and there is nothing to pull against - totally suggest @Spoon Unit 's fan guard to prevent fingers in fan blades when changing)
     
  11. Alex Stevenson

    Alex Stevenson Well-Known Member

    Joined:
    Sep 4, 2015
    Messages:
    87
    Likes Received:
    14
    Old_Tafr likes this.
  12. Razar

    Razar Member

    Joined:
    Sep 6, 2015
    Messages:
    6
    Likes Received:
    2
    After the first print section on the wiki there should really be a short introduction on how to make a filament change and a note not to turn of the printer until the hotend temp has stabilized.

    Got my first clog right after my first print from heat-creep after a PLA print. I guess its more of a enthusiast printer but there should be some more basic info still.

    There is no video on the tension of the filament idler and how to press it down in a good way this is one of those things that is hard to write up in words how much tension there should be and how it should feel when done. I think there are more people then i that have sore fingers from the idler system..

    There is allot of good info in this forum and online youtube ect. but it can be hard to track down what is relevant to this printer and setup. Unless you know what you are doing from before that is.

    Oh i nearly forgot to mention that my first print ended halfway in tangled filament o_O -What there are knots on filament spools??:eek: -No but they get tangled easily so you have to check the entire spool role before a print.
     
    Alex Stevenson likes this.

Share This Page