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Dried Spaghetti on bottom layer but then fine for all other layers

Discussion in 'Troubleshooting' started by Eric Viglotti, Dec 8, 2019.

  1. Eric Viglotti

    Eric Viglotti Member

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    Over the years I have had many challenges with the bottom layer but was doing great for awhile but now many of the prints have had the same challenge...If you look at the attached, the first layer is a mess of what ultimately looks like dried spaghetti or pick up sticks. The 2nd layer and above is all fine but this first layer comes off the bed with a mess of dried lines. I've replaced the R2 buildtak surface and am using the same Simplify3D settings I have used for years with a slow and extra material first layer. I have seen this with many spools of filament.

    My hunch is this is simply just a z-offset issue where it's not close enough to the bed, but any closer and I have to take a hammer to the buildtak spatula to get the print off and I end up chipping the bottom layer.

    I'll definitely keep playing with lowering the z-offset but just wanted to make sure I wasn't overlooking something else someone has had work for them.

    Thanks!
     

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  2. Eric Viglotti

    Eric Viglotti Member

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    And FYI, it tends not to be the whole first layer just sections which right now is any section towards the front 1/2 of the bed. I guess that just means a.) my bed isn't level and b.) I must not be small enough of a z-offset so that the back half is just about fine and the front half is such that the lines don't connect from pass to pass. I could swear I checked the bed level but I'll check it again.

    But I guess more globally...do most people have a situation where it is either a mess of a first layer like this or any 0.01 changes to the z-offset that fix this make it so that a hammer to the buildtak spatula is needed? Has always seemed to be excessive but that's basically what I have been doing for years.

    Thanks.
     
  3. tkoco

    tkoco - -.- --- -.-. ---
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    Try increasing the default layer width from the default setting of 0.4 mm to 0.42 mm
     
  4. Eric Viglotti

    Eric Viglotti Member

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    Interesting. Currently I have "First Layer Width" set to 150%. Wouldn't that be better than changing the "extrusion width" from 0.4 to 0.42 on all layers? It would seem like affecting all layers would trade one problem for another :(
     
  5. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Well, in reality, filament normally expands a bit after it comes out of the nozzle and for PLA the average is 120% of the nozzle diameter.
    Some of that is also due to the fact that the filament is PUSHED down into place so you would expect it to expand :) That will happen more on the first layer than the others (because your slicer is squished the first layer more for adhesion) but it will happen on all of them if it is working.
     
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  6. tkoco

    tkoco - -.- --- -.-. ---
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    Are you talking about the flow rate in the material settings? it should be 100% and not 150%. The line width of 0.42 for all layers has the effect of better line to line (side to side) adhesion. Using a flow rate greater than 100% can mess up other calculations and possibly cause over extrusion. Try backing down the flow rate to 100% and bump up the line width to 0.42. See if that makes the spaghetti problem get better.

    As @mark tomlinson pointed out, filament expands a tad while printing the first layer. Asking for a slightly wider line width helps enhance the expansion of filament without going overboard.
     
  7. Eric Viglotti

    Eric Viglotti Member

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    In case it helps, attached are my S3D settings on the two noteworthy panels.

    Thanks.
     

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  8. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Ditto on this. Unless the slicer is doing something wrong, setting the width is enough. Let it calculate the correct flow rate. If you are adjusting flow rate you are overriding the slicer and this may have other unintended affects (unless you know exactly how it calculates the flow rate -- and I sure do not).
     
  9. tkoco

    tkoco - -.- --- -.-. ---
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    Yes, the images do help.

    First Image: Extruder width - try using 0.42. Leave the nozzle at 0.4

    Second Image: First Layer Width - try 100%; First Layer Height - that parameter, try 100%.

    Keep in mind that you can always restore the values to what you currently have.

    Are you printing with PLA or a different type of filament?
     
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  10. Eric Viglotti

    Eric Viglotti Member

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    Perfect, I will try this out, much appreciated.
     
  11. tkoco

    tkoco - -.- --- -.-. ---
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    Please let us know how it goes. Also let us know what filament you are using as well as the printing temperature.
     
  12. Eric Viglotti

    Eric Viglotti Member

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    Oh, right, sorry, 190 extruder, 60 bed. PLA
     
  13. tkoco

    tkoco - -.- --- -.-. ---
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    Suggestion: Bump the PLA temperature to 195 and drop the bed temp to 30.

    60 C for the print bed is excessive for PLA. I would not recommend using anything higher than 40 C - and that's for the other filaments like PetG. I have a C2 printer which lacks a heated print bed. PLA prints just fine on my C2.

    The the melt path for the standard hot-end for the R2 is short when compared to a volcano hot-end. So a slightly higher print temperature usually helps with the flow. However, if 195 C causes excessive stringing, then consider using 192 - 193.

    One other thing, leave the Robo magnetic plate off of the front of the Extruder assembly. Leaving it open ended helps prevent heat creep which can cause a clog /blockage.
     
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  14. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    I agree. I say that, but I still use a "warm" bed for PLA (30C) just because it makes me feel better, but I have on the R1/C2 and others used a room temperature bed for PLA and it is fine if your slicer and printer are working correctly.

    You can actually with too hot of a bed make PLA want to warp somewhat on larger, flatter models in particular.
     
  15. tkoco

    tkoco - -.- --- -.-. ---
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  16. Eric Viglotti

    Eric Viglotti Member

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    Thanks, I'll definitely try all of this and you're right, the Flexplate idea might be a real good one. Thanks!
     
  17. adikted2astro

    adikted2astro Active Member

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    I can confirm this. I never leave my front plate on anymore. As a matter of fact, I'm not exactly sure where it is???????????

    It's something I should've realized long ago, but having that front plate on is a bad thing, even when printing PLA. And when you try to print plastics like nylon and TPU, it will most certainly cause heat creep.
     
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  18. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    I have been lucky and mine have not exhibited that symptom, but you are right -- leaving it off can only help.
    My C2 has TWO hotends in there and even with both going I don't see heat creep... I suspect some of the fans are just not up-to-snuff (made in China and all that...)
     
  19. Eric Viglotti

    Eric Viglotti Member

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    Interesting. After the holidays I'm definitely going to try all of these suggestions.
     
  20. tkoco

    tkoco - -.- --- -.-. ---
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    Lucky for you. :) However, fans eventually fail and will need replacing.
     
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