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Problems with globs on first layer only

Discussion in 'Troubleshooting' started by JJHawg, Oct 18, 2013.

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  1. JJHawg

    JJHawg New Member

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    I am doing some tuning of the printer using a 20mm x 20mm x 10mm solid block...
    I am using .3mm layer thickness, 3 perimeter, 3 top and bottom solid. 40% infill, every layer, solid every 5...
    All other settings are pretty much default.

    The block prints nearly flawlessly, except for the first layer solid [rectilinear] infill. The first layer perimeter is fine, but when the head moves back and forth for the fill it seems to pick up material from the previous pass, plus it almost looks like travels part way into the perimeter. The globs tend to accumulate near the center of the pass, not the ends...

    Fortunately, the next 2 solid layers knock down the globs, and the 40% honeycomb layers over the flaw nicely. The intermediate and top solid rectilinear layers are perfect, it is only the first one causing problems. I have changed some of the flow settings in the advanced section, but no significant changes observed...

    Has anyone else encountered this problem? Any ideas?

    Thanks, Jim
     
    #1 JJHawg, Oct 18, 2013
  2. Soupaboy

    Soupaboy Active Member

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    any pictures of the globs? .3mm is quite large. I heard the the robo should be at .2. have your tried using a different resolution?
     
    #2 Soupaboy, Oct 19, 2013
  3. tesseract

    tesseract Moderator
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    as I said it is a height issue
    did you print with skirts
    I use skirts and they can tell you if you height is the correct level really easily if it isn't things like what you are seeing occurs
    .3mm is fine as a resolution there is no standard resolution it is completely a user preference

    first layer example.jpg

    The skirt in this print is in my opinion pretty good it is slightly flattened and solid that is what you want other variations can have issues so try and make it look like this

    Basic Rule use skirts look at them if they are good continue with print if they are not good STOP adjust the height and restart

    it will save you time and material
     
    #3 tesseract, Oct 19, 2013
  4. JJHawg

    JJHawg New Member

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    On Monday I will post some pictures of (and hopefully the resolution to) globs that I see...

    I had this fantasy that I would tune configurations for .1, .2, and .3 layer thicknesses. After reading many posts on the Web I see that some people expect one good setting for their machine; I will probably select .2 and use it for everything...

    My current problem is interesting because everything else about the print is almost perfect, just not the first layer... This means that I'm close... ;-)
     
    #4 JJHawg, Oct 19, 2013
  5. Printed Solid

    Printed Solid Volunteer Admin
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    It sounds like you are either extruding too much material or too close (don't hear that too often...) on the first layer.

    If you have it set to extrude at a higher rate at the first layer, which I believe is the default in slic3r, turn it down a bit.
     
    #5 Printed Solid, Oct 19, 2013
  6. JJHawg

    JJHawg New Member

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    Here are a couple of pictures... They are using 0.2mm height instead of the 0.3mm I was using earlier, but still with problems.

    "FirstLayerInfillBlobs" shows the globs that accumulate during the first layer solid infill. I compared the g-code for different "Extrusion Width: First Layer" settings and it looks to me like the horizontal step-over between passes doesn't compensate enough for the extra material extruded when the width setting is increased... But if this was a Slic3r bug, everyone would be having the same problem, right?

    "InteriorSolidInfill..." shows a very nice solid pass over two honeycomb passes. These layers hid the messed up first layer, and it shows that everything is working fine, only the first layer solid infill has the problem.

    I verified that I am running the latest versions of all software, and I have tried this test with almost every possible combination of settings, starting with defaults and minor variations to them.

    I can even see a difference between the first and interior solid layers when viewing the g-code layer-by-layer in Repitier-Host...

    [Just for fun I did a fresh install of the software (using all default settings) on another laptop running a different OS, and I get the same results...] I also found a post on Github with similar complaints...
     

    Attached Files:

    #6 JJHawg, Oct 21, 2013
  7. Coby Robo 3D

    Coby Robo 3D Administrator
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    JJ, Your first layer is too low, by just a teensy bit. Also, from your pictures, it looks like the right side of your x axis is a bit lower than your left side as well. Try re-leveling and see what happens
     
    #7 Coby Robo 3D, Oct 21, 2013
  8. Coby Robo 3D

    Coby Robo 3D Administrator
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    Some other things you can try:

    1. Print with a raft to help with the troublesome first layers
    2. Set your first layer height to be a bit larger to make it easier to get it to stick and be level. (we use 0.3mm for our first layer height)
     
    #8 Coby Robo 3D, Oct 21, 2013
  9. JJHawg

    JJHawg New Member

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    Thanks Coby, it seems so obvious now... ;-)

    Since the perimeters looked good I didn't consider this, but in fact the perimeters only looked good because there were so few passes compared to the solid fill...

    I set the initial spacing with a business card instead of a piece of paper, and am getting good results. I tried rafting once, but had some trouble cleaning up the bottom of the part, maybe I will try again...

    Thanks,
    Jim
     
    #9 JJHawg, Oct 21, 2013
  10. Memnoch

    Memnoch New Member

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    Does anyone know how to flip the item upside down in Rep-Host. I tried to print the Cigar hard case and it crapped out about halfway thru. basically it was not stable enough to stay put. I want to put the wider end down to print first. I think that might make it more stable as it gets taller.
     
    #10 Memnoch, Dec 26, 2013
  11. Soupaboy

    Soupaboy Active Member

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    Under scale this is x=0 y=0 z=0 type thing. Change those numbers to turn -flip or rais it
     
    #11 Soupaboy, Dec 26, 2013
    2 people like this.
  12. scotta

    scotta Active Member

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    On the object placement tab in rep-rap. As soupaboy states there are a Rotation x,y,z fields. enter a rotation value in degrees.
     
    #12 scotta, Dec 27, 2013
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  13. Memnoch

    Memnoch New Member

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    Thanks, that seems to fix that problem.
     
    #13 Memnoch, Dec 31, 2013
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