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Solved Bottom layer has gaps

Discussion in 'Troubleshooting' started by znet3d, Apr 4, 2016.

  1. znet3d

    znet3d New Member

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    Dear Robo3d community,
    This is my first 3D printer and I have been learning a lot and I have a lot more to learn, I was hoping someone could help me with which settings I need to tweak to get a good bottom layer to print. I have printed lots of small things to get a grasp on the process. This was my first large print, the spool holder. The print went well and the item looks good, except the bottom layer. As you can see in the picture, it’s not smooth at all and has gaps. What could cause that? How would I go about fine tuning settings to get a good smooth bottom layer? I have been using the MC for software and mostly the preloaded settings that came with it, the only thing I really have been messing with is the infill and print quality. I have seen settings for the outer layer and I have set that to “Fine” which was set to 1mm and I did find a percentage settings for the first layer under “advanced” options it is set to 30% should that be lowered? Small items that do not have a large/long first layer like the oiler that was posted on the forums came out looking great. Thank you for your support.
     

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  2. GAmbrosio

    GAmbrosio Active Member

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    I get that usually when I have bad adhesion to the build plate/hot bed. This can be caused by contaminants, either on the bed itself, the filament, Etc. I would start by cleaning the bed. I use glass cleaner with ammonia and follow up with a 99% Isopropyl alcohol or denatured alcohol ( excellent glass cleaner) this should dissolve anything on your bed.

    Then, as recommended by Robo, I use hairspray. Not all are created equal as it seems- I use AquaNet, extra super hold- Wally World: $1.98. Spray a light coat, let it dry, spray a second coat and let that dry.

    Try again and see if it makes it better.


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  3. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    The initial Z offset controls how the first layer is laid down. If it is too high (for example) you will likely get gaps between the lines.
    That however, looks more like inconsistent extrusion than a Z offset issue. You might try calibrating the extruder.

     
  4. MChrisP1

    MChrisP1 Member

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    Ok I used to see that problem, albeit not to that degree, when I was running my Robo at 210 for PLA.

    I backed my extruder temp back to 200 and I see that happen very rarely now.

    I think when the extruder is too hot for a plastic, it gets messy like that sometimes.

    Maybe try backing temps back a bit. I use PLA from hatchbox, and it seems to like that 200 mark. But remember each individual roll can have a preference/ideal temp.


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  5. KTMDirtFace

    KTMDirtFace Well-Known Member

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    Your z offset could actually be too close too. I get goobers like that if its too close.
     
  6. znet3d

    znet3d New Member

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    Thank you for all your feedback, I am using the hatchbox filament and will try to lower the temp. The printer bed was nice and clean when I did the print of the spool holder and I did use the glue stick that came with the printer. I am not sure where to find or how to set my z offset, I don't see the m565 in my gcode and the Robo documentation says my offset should be 1 and it was 0 by default is this where I should be changing it/looking for it? Thank you.
     

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  7. MChrisP1

    MChrisP1 Member

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    Go to Controls, look down the page, there are macros for z offset. The standard offset is set to .9, so you can try .8... Hit that macro button once and you are set until you hit a different macro button. See user's guide :)


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  8. znet3d

    znet3d New Member

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    Hello,

    I apologies it took me couple of days to tryout some of the suggestions you guys provided. So I used the Macro buttons to play with different offsets (I did see those before, but then I read another post of a person asking if he should use those and someone replayed, no use the m565 gcode, that’s why I asked in my earlier post). The pictures below are with the offset set to 1, first layer thickness set to .4, extruder temp at 200, bed temp at 60, first layer speed reduced to 17% which shows as 10mm/s. I am not getting the gaps as you can see but it’s not as smooth as I would like it.

    Having some trouble with the basics:

    So I thought thinner layer would give me a smoother surface, but setting the first layer to .4 help to cover the gaps I was having.

    I really think the first layer speed had the most affect, it is very slow printing the first layer, is this common to have a slow first layer speed, I noticed on Thingevers some ppl printing instructions stated slow first layer setting. Having a higher offset, now having more issues getting things to stick, needed to use more glue. Plus I though having a lower offset would be better for the layers because of the “squishing” of the layer, right?

    I am confused on the bottom layer thickness to solid settings and the perimeter count settings. So a thicker bottom layer would help me get a smoother surface and the perimeter count settings would make the shell of the whole item stronger with a higher count? Doest the perimeter count also affect the bottom layer?

    Thank you all for you advice.
     

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  9. GAmbrosio

    GAmbrosio Active Member

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    I think that looks like a z offset thing, the nozzle is too close and is scraping the layers. I don't remember how to do it in MC, since I've been seduced by S3D and have not looked back :) but someone here will know.


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  10. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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