5 colour printing using a purge "bucket"



  • I've just done a bit of a post on my blog about using a purge bucket for anyone who may be interested. It is still under development but showing good promise. It is the latest tool in my armoury of different purge methods for different situations. The post can be found here https://somei3deas.wordpress.com/2017/12/06/5-colour-printing-with-a-purge-bucket/ but the the associated video probably explains it all and is here https://www.youtube.com/watch?v=zNNmZCXErYY&t=278s



  • Hi Ian,

    Nice!
    What is your experience with reliability. Did a lot of different wiping setups for the magnetic tool changer and most times the single blade would fail like 1 out of 50 times just wiping the filament strand to the other side of the nozzle. Especially if it tends to curl upwards for some reason.



  • @foehnsturm:

    Hi Ian,

    Nice!
    What is your experience with reliability. Did a lot of different wiping setups for the magnetic tool changer and most times the single blade would fail like 1 out of 50 times just wiping the filament strand to the other side of the nozzle. Especially if it tends to curl upwards for some reason.

    Thus far it's OK but I'd say that it's probably only done between 50 and 100 wipes so long term reliability is untested. Initially I did find that simply extruding filament then passing back across the strip could make the extruded filament curly up and get carried away with the nozzle. That's why I added the extra wipe whereby the nozzle moves 20mm to the right at it moves forward across the strip, then another 20mm further right as it moves back again before finally moving forward to the print position. Each filament uses a different section of the silicone strip. Tool 0 goes to X=50, extrudes then wipes back and forth to X=90. Tool 1 goes to X=100 then wipes to 140, etc. So I'd hope that the silicone strip should last a fair while before it needs replacing. I had to buy 5 metres of it and it's only 360mm long so I have plenty of spare strip ๐Ÿ™‚



  • That's an impressive machine!



  • @DeltaCon:

    That's an impressive machine!

    Thanks. Although "insane" is the term that most people use to describe it (including me) ๐Ÿ™‚



  • Hi Ian,
    That is working well! I like the side to side movement while wiping. I'm going to do some re-deign on my setup and use a longer purge/wipe area on each side of my printer.

    Thank you for the info.



  • @timcurtis67:

    Hi Ian,
    That is working well! I like the side to side movement while wiping. I'm going to do some re-deign on my setup and use a longer purge/wipe area on each side of my printer.

    Thank you for the info.

    Hi Tim,

    Glad you found it useful. I have an idea for a future upgrade which involves using an Archimedes screw to collect the debris and move it into a container. If I do that, I might also try something like a rotating bottle brush instead of the static silicone strip. I don't know if it'll ever get of the ground though - depends on if I can print an Archimedes screw ๐Ÿ™‚

    Edit -a moving conveyor might be easier - something using wide timing belt would be easy to implement - hmmmmโ€ฆ...

    Second edit - driven by a stepper or small motor that is energised only during the purge cycle - more hmmmm..........



  • This one http://foehnsturm.com/3dp/P1070095.m4v was actually working reliable but threw the stuff all over the place ๐Ÿ˜‰



  • Ian, A slow turning screw would work well. It's more like a spiral wound piece of wire (square stock) We have them at work on most of our machines to carry metal chips out of the machines. If I knew how to post a picture on here I could show you what they look like.

    I think they would be easy to implement, now if we can get David to add another mcode to turn them on /offโ€ฆ. ๐Ÿ™‚



  • We already have M42 so it shouldn't be too difficult to cobble something together that could be switched via an IO pin.



  • Ian,
    I just email you some pictures of the screw auger I was talking about. I think I am going to try something along this line.

    Tim



  • @timcurtis67:

    Ian,
    I just email you some pictures of the screw auger I was talking about. I think I am going to try something along this line.

    Tim

    Hi Tim. Haven't received any email yet but yes, I understand what you mean by an auger and that's along the lines of what I was thinking.



  • I've actually been thinking of doing something just like this.

    Would bumping the part fan to 100% help manage the waste filament?

    Could also do a "wire brush" area for the nozzle to run through to get the big chunks then hit the silicone strip for the final wipe before returning to the print area.

    Personally, I think giving up a little bit of build volume is worth while for the amount of filament you save.



  • Bold text below is just to distinguish my comments from the original quoted text and not because I'm shouting ๐Ÿ™‚

    @Mk_Nick:

    I've actually been thinking of doing something just like this.

    Would bumping the part fan to 100% help manage the waste filament?

    That's a very good question. It'll cool the filament as it comes out and should make it solidify quicker. I don't know if that would be a help or a hindrance. If I get chance, I'll test it (it's easy enoughy to do).

    Could also do a "wire brush" area for the nozzle to run through to get the big chunks then hit the silicone strip for the final wipe before returning to the print area.

    I think the problem with this might be that the the brush gets clogged or at least retains some of the previously purged filament which could then stick to the nozzle on the next pass. That's what happened with my "MK1 bucket" so I made the "MK2" which essentially has no bottom and allows the filament to drop through.

    Personally, I think giving up a little bit of build volume is worth while for the amount of filament you save.

    Also, if you use any sort of "tower", it will also take up some of the available space so a bucket is no worse than a tower in that respect. (I guess that's not strictly true as a tower could be positioned at some other unused part of the bed to suit the model being printed).


  • administrators

    Tim if you post pictures on a file sharing site like imjur you can then embed them in your post.

    Ian, loving your work as usual!



  • I've just tweaked my blog post to elaborate a bit on the purge gcodes that I used. So for those who have already read it, the additions I have made are as follows:

    Firstly, I'm using firmware retraction so for anyone who wants to try it and doesn't use firmware retraction, you'll need to substitute G10 with whatever gcode you use to retract filament (e.g G1 E-nnn Fnnn) and likewise for G11 un-retract.

    Secondly, the first command of the purge sequence is G10 (retract). I'm using Slic3R which by default puts a G10 before the tool change so thee could be 2 consecutive retract commands in the gcode file. I've left it in though because other slicers may behave differently and Duet firmware won't act on a second retract if there has been no preceding unretract, so it does no harm.

    Lastly, there is an unretract immediately before the extrusion which may seem unnecessary but it is needed because I want to retract after extruding to prevent any oozing so there has to be a preceding unretract (hope that makes sense).



  • @T3P3Tony:

    โ€ฆ...........
    Ian, loving your work as usual!

    Thanks Tony but I'm not claiming to have done anything new or ground breaking. The principle of using a purge bucket has been around for a long time. I just thought it might be useful to do a write up on my particular approach to implementing it. (It's always nice to have one's efforts appreciated though).



  • Nicely implemented!



  • Nice machine! love the sound the machine made while traveling.


 

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