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Raft

Discussion in 'Troubleshooting' started by Eric Viglotti, Jan 18, 2018.

  1. Eric Viglotti

    Eric Viglotti Member

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    Hello,

    I am official tired of trying to prevent warping/curling on my prints and I think it's time to start using a raft again.

    I am using Cura version 2.6 for my R2 and when I select Raft it is using the default settings:

    Air Gap: 0.3mm
    Initial Layer z-overlap: 0.15mm
    Raft top layers: 2

    However, the problem is I can't get the raft off the print. In fact, even the 3d benchy print that comes pre-loaded on the printer has the same problem. However, I knew what rafts should do as I used to have the raft on my R1+ working like a champ.

    Anyone know what setting to change to make the raft be able to be taken off better?

    Thanks!
     
    #1 Eric Viglotti, Jan 18, 2018
  2. Geof

    Geof Volunteer Moderator
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    Your air gap sets the distance between the printed part and the raft. Increase that by small amounts until the raft peels away. Temperature also plays a roll (and could be the cause of your warping if PLA and to hot) so make sure your not running to hot or hte printed part and raft may likely fuse together.
     
    #2 Geof, Jan 19, 2018
  3. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Exactly. Too hot and the plastic will flow too well and you get excessive adhesion because it is flowing beyond what it should. When you are dealing with the tolerances at layer heights (say 0.2mm or less) a little bit off and you will be in trouble.
     
    #3 mark tomlinson, Jan 19, 2018
  4. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Temperatures for any given spool are a dance. First, your printer (extruder specifics like heater core size, etc) matters then the material matters (even spools of the same material from the same vendor my have slightly different sweet spots) and lastly the environment matters (how hot/cold/humid the room is). Experiment. In the world of A/C most rooms run fairly consistent environments (and if not that will give you some problems). The range they print on the spool is an average across that brand and type. Consider it "guidelines" for where to start testing.
     
    #4 mark tomlinson, Jan 19, 2018
  5. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    In other words; We are not here to tell you what to do, rather to tell you how to figure out stuff for yourself.*


    *In most cases ;)
     
    #5 WheresWaldo, Jan 19, 2018
    mark tomlinson likes this.
  6. Eric Viglotti

    Eric Viglotti Member

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    All good input, thanks much everyone. I moved the air gap from 0.3mm to 0.4mm and the raft came off perfectly.

    What's weird though is if you look at the "underside + raft" picture, the raft is perfectly clean on both top and bottom faces, but the bottom of the actual printed item is really messy and dimpled looking. My experience is that if the z-offset is too low, the nozzle seems to "rub" on the first layer creating this. But I wouldn't think that is the case with the raft because does the z-offset even matter at that point since you're not really on the "first layer"? Or is this rippling something else?

    As an aside, the top face of this printed little box (just as a test) has these little raised dots, not sure what that is or if it's related...

    thanks!
     

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    #6 Eric Viglotti, Jan 19, 2018
  7. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    If this was PLA my first guess on the bottom was you are extruding just a bit too hot. And it has to bridge (not the exact term but close) so the bottom of the model is not as smooth as it could be. With regard the top, that dimpling you see is because you don't have enough top layers for the given layer height.
     
    #7 WheresWaldo, Jan 20, 2018
  8. Eric Viglotti

    Eric Viglotti Member

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    Sounds good, no worries on the top layer, that makes sense. As for the bottom layer, yes, I should have mentioned, this is PLA and I'm printing at 200 degrees on the nozzle and 60 on the bed which is the default for the PLA material in Cura. Should I reduce this to something else? I've pretty much always printed at 190 or 200 for PLA with both my R1+ and R2.
     
    #8 Eric Viglotti, Jan 20, 2018
  9. Eric Viglotti

    Eric Viglotti Member

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    I have to say I am at a loss as to what in the heck this is...This is with PLA on an R2 and I have done this now at 200 and 190 and now at 8.7, 8.8 and 8.9 z-offset and this raft is just super mucked up and it then seems to carry over into the bottom of the actual print...
     

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    #9 Eric Viglotti, Jan 20, 2018
  10. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    My default suggestion is to try another silcer. Some do rafts well, some do not.
    You might want to start though by running a temperature testing print (like a temperature tower) or something since some sections of that picture look like it is still printing too hot. A quick test I have done in the past is here: http://community.robo3d.com/index.php?threads/cant-complete-a-print-pla.3093/#post-27211

    Every spool can be a touch different.
     
    #10 mark tomlinson, Jan 21, 2018
  11. Eric Viglotti

    Eric Viglotti Member

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    Very cool, will check out the temperature tower. If I were to switch slicers, would Simplify3D be a good choice? I don't have a problem spending money on it, but only if it actually works with the R2 and actually has some improvement over Cura from what people have seen in these forums, etc.
     
    #11 Eric Viglotti, Jan 21, 2018
  12. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    @Geof can speak to how it works on the R2, I have used it on C2, R1, R1+, A delta and other FDM (Ultimaker) and a few others.

    Never a problem that wasn't me.
     
    #12 mark tomlinson, Jan 21, 2018
  13. Eric Viglotti

    Eric Viglotti Member

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    FYI, I went ahead and bought/downloaded Simplify3D and used the default R2 settings on this with a raft and attached is what I got as the bottom of the part and the bottom of the raft. It is night and day and could not be more perfect, so I'll keep playing with Simplify3D, but I didn't change anything else on the printer and had it at all default settings, which include 200 on the extruder and 60 on the bed. I had no idea a slicer could make this much of a difference...
     

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    #13 Eric Viglotti, Jan 21, 2018
  14. Geof

    Geof Volunteer Moderator
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    sorry for the late response. I've never regretted getting Simplifiy 3D for the same reason (and many many more) but most times the settings just work, or are a heck of alot closer than most free profiles (even curated ones :D).
     
    #14 Geof, Jan 22, 2018
  15. Eric Viglotti

    Eric Viglotti Member

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    No worries, perfect, thank you all!
     
    #15 Eric Viglotti, Jan 22, 2018

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