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Printing with ABS.

Discussion in 'General Questions' started by Bruno Albuquerque, Dec 22, 2017.

  1. Bruno Albuquerque

    Bruno Albuquerque New Member

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    First of all, I am new to all this 3D printing business and just got a Robo R2 for xmas. I was able to print with the included red PLA filament without issues and was actually pretty satisfied with the quality I got.

    Then I bought some generic ABS filament from amazon just to experiment (bought a few different brands, none of which was Robo) and tried to print with it but the filament would not stick at all. I even tried buying Buildtack and using it but although the filament now stick somewhat, it would always end up getting loose from the bed at some point and I had to abort the print. I have some questions about this:

    1 - In general terms, would I have better success with Robo-branded ABS? It is almost double the price compared to the ones I bought.
    2 - Is loading a generic ABS filament in the printer as "Robo ABS" ok? Should I create different profiles for different ABS brands? If so, based on what?
    3 - Is there anything I am missing that would help getting ABS to stick to the bed?

    On a tangentially related note, I could not find replacement PEI sheets for the R2 on Robo's site (I was looking just out of curiosity. Not that I think that I need one now). If I ever need one, are they generic so I can buy it anywhere (taking into account the bed dimensions, of course). Also, should I remove the PEI sheet if I want to use Buildtak (because I just applied it over the PEI sheet)?

    Thanks in advance.
     
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    1. No.
    2. Yes, it is as good as what anyone sells in almost all cases.
    3. You can try things like this: https://airwolf3d.com/shop/wolfbite-prevents-3d-printed-parts-from-warping/
    However ABS is intended for use on a 3D printer with an enclosed heated chamber. Not really a description of many consumer 3D printers :) Now, can you make it work? Sure -- minimize airflow and use things (like WofBite or ABS 'juice') to encourage the ABS to stick to the glass. You may still have issues with warping and curling and things like that. I always suggest knowing what material property you are expecting ABS to deliver and then use a (better) alternative -- see this list:

    http://taulman3d.com/how-to-choose.html

    There is no one property of ABS that is not met or exceeded by an easier to print material. Price is the only thing that ABS will generally win on... it can be had really cheap :)
     
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  3. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    If I need a high deflection temperature I use BluPrint, if I want sheer strength then a nylon or Alloy910....
    You get the idea :)
     
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  4. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    PolyCarbonate filament can be a hassle too (although some vendors have versions that print relatively easier). However if you need the properties of Polycarb then you don't have a lot of alternatives :)
     
  5. Kilrah

    Kilrah Well-Known Member

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    I've printed a few things with success in ABS, using large brims.
    But yeah I rarely use some, only got a dirt cheap roll at a clearance sale to try but ABS is indeed just not a great choice of material given the current alternatives. I do like polycarbonate as someone said I would :)

    20170702_204223.jpg 20170831_204751.jpg
     
  6. RSC

    RSC New Member

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    ABS is a difficult filament to print with. It has a big "coefficient of thermal expansion" and so, changes size significantly as it heats and cools (on the order of 5% or more shrinkage as extruded ABS cools), which leads to easy warping. There are lots of ways to address the problem. But if you're new to 3D printing, I recommend you stick with PLA while you learn the ropes. Once you're getting perfect PLA prints, go to more challenging materials and you'll have a better idea of what things you might tweak to achieve your new objectives.
     
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  7. Park A.

    Park A. New Member

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    I think another important factor, especially with ABS, is your z-offset. I tried, and tried, and tried, sooo hard to get perfect ABS prints; but when doing so, at first, I only focused on temperature and isolating my print. I got close, but never anything consistent. It wasn't until I focused on my z-offset that everything started coming together with my ABS prints. Just a fraction of a mm (high OR low) might be the difference between a flat bottom success or an abort at 4%.
     
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  8. Park A.

    Park A. New Member

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    Safe to say you've got the v2 bed. . .

    BL: Any 8x8 buildtak sheet will work. Use caution when you place it though. The actual bed surface is larger than 8x8. Take note where your nozzle stops for your z-offset, fine tuning, and bed calibration wizards; you want to make certain your 8x8 covers those areas, so your measurments are consistent. If you simply center the 8x8 on your bed, you'll miss the z-offset stop (or you'll have to change the z-offset stop).

    Definitely remove the old PEI, it's not that difficult and this way you're working on the aluminum base. I don't think you'd hurt anything stacking on top of the original PEI sheet. But it may insulate, not allowing the actual bed temp to reach your print. Maybe?

    Hope this helps, and MERRY CHRISTMAS!
     
  9. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    Just to add to what @Park A. said about dimensions of the new sheet. The thickness Robo uses is 0.8 mm so a sheet that is anywhere from there and thicker will work. If you want to cover the screws too (unnecessary since the build platform is a bit smaller) you need about 9 inches square. Many sellers have 254 mm square (10" square) pieces for sale and they can be cut with a straight edge and sharp blade. Make several passes do not try top cut through the material all at once.
     
  10. RSC

    RSC New Member

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    I used to use Kapton tape on my build plate for ABS back in my Replicator days. Worked great. And I still have a couple of rolls. How is the PEI stuck down? Just pressure-sensitive adhesive?
     
  11. Geof

    Geof Volunteer Moderator
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    3m adhesive (so yes)
     
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  12. Jeff Lastofka

    Jeff Lastofka Member

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    I just got a new R2 (March 2018) and the information says it's a PEI bed. I see the replacement part on Robo's site is Buildtak. Is there some misinformation here? Is mine actually PEI or is the information old and I actually have Buildtak? Am I going to get all my setups working with PEI and then when I buy a replacement it will be different and I'll need to readjust settings? My bed cover has notches for the screws and the Buildtak sheet for sale on the Robo site doesn't show the notches, so I suppose that's a clue, but not necessarily. Could just be a factory assembly step they do.
     
  13. Geof

    Geof Volunteer Moderator
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    V1 - PEI covered bed with Pogo pins.

    V1 had issues where the Pogo pins would die on some machines depending on the use.

    Fix:

    V2- direct connection- no pogo pins, not as easily removable, Buildtak instead of PEI.


    If you experience issues request a V2 bed.
     
  14. Jeff Lastofka

    Jeff Lastofka Member

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    I just learned from a friend the appearance difference between glossy PEI and flat Buildtak and it seems I have Buildtak for sure, even though it has notches for the screws and the replacement part looks a bit different without the notches.

    My bed is attached to a cable with a little edge connector with a quick release finger tab so you can take the bed to another table. I find I can just lift the bed out a short distance and work on it without unplugging the cable. I don't see any pogo pins.
     
  15. Geof

    Geof Volunteer Moderator
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    Then you have a Rev 2 bed (thats a good thing :D) should say Robo in whitish grey lettering towards the front. The Rev 2 bed is fine, but the pogo pins are annoying if you experience the failures. I print high temp materials often (like you with ABS) and the pogo springs just couldn't handle the heat.
     
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  16. Jeff Lastofka

    Jeff Lastofka Member

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    Thanks. Whitish grey lettering. Check. I think I'll try a lower bed temperature for PLA. The parts are sticking a lot stronger than necessary if you ask me. I'm looking forward to trying ABS with the new enclosed housing. Should help thermal contraction issues some. I printed a lot of Ninjaflex on my R1+ with a simple modification to the head. Looking forward to trying that here, too. Perhaps I'll hang the spool overhead if it's too difficult to get through the feed tube. I'll need a piece of dummy filament to fool the empty sensor... Maybe I'll need a little modification for the feed on this printer, too, but I'm getting too far away from the origin of this thread, so I should stop.
     
  17. Geof

    Geof Volunteer Moderator
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    lol its your thread, drift away my friend. Can fire one up in off topic as well if you want to just banter ;) .

    PLA doesn't need bed heat, so I typically never exceed 60 (normally 50 or less). Buildtak loves to stick hard, more so when new. Increase your z offset a smidge (further the distance from the bed an the nozzle) for the first layer and that should help, just dont go to much or you will curl and warp :D

    I ran some semiflex and TPU through my R2 but my R1+ machines are better suited for that kind of thing (and a few other machines) so I just let them do that :D. Sometimes its not worth the headache...but if you ditched the R1+ were gonna have to have you do a mods/upgrades thread on your R2 with what you did to make it work :D (please?)
     
  18. Jeff Lastofka

    Jeff Lastofka Member

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    I might be keeping the R1+. We'll see. The modification was just drilling out the hole between the feed gear and the extruder a little larger to accept a short piece of the Teflon filament guide tube, cut height just short of hitting the feed gear. It supports soft filaments against buckling and doesn't affect other filaments so I leave it in there all the time. I also turned the printer around backwards to make it easier to see and reach while loading filament and I modified the various clamp and spring parts to make it easier to work around them. It's a LOT nicer for loading filaments now. The only difference is the parts print facing the other way from what you see on the computer screen:) I also put in several quieter cooling fans (my R2 might want one on the extruder cooler) and added heater tapes around the periphery under the glass bed to get a uniform temperature distribution over the entire surface. Scanning the R2 bed with an IR thermometer shows a pretty even distribution when set at 60C, although the actual surface temperature's closer to 40C.
    It's fun when you get a product that basically works, but then you can hotrod it to personal taste. Looks like the R2 is a big general improvement over the R1+ and there will likely be fewer "improvements" I'll want to add. Good times:)
     
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