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Weird markings on bottom of print


TlW

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Posted · Weird markings on bottom of print

It looks like it was extruding from one direction, quit near the middle, and then came from the other side.  The extrusions don't line up.  It could be a setting or the bottom of the model isn't flat??

With the model loaded in Cura, and Cura set up ready to slice, use the "File | Save Project" command and post the 3mf file here.  Someone will take a look.

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    Posted · Weird markings on bottom of print

    Also keep in mind Cura likes to put down 120% flow (or something like that) for the first layer to make it "stick" buy smooshing it into the bed more. I personally find this leads to a messy first layer, I usually drop it back down to 100%, sometimes even less depending on the material and the temperatures.

     

    For instance when I print carbon filled nylon I usually end up with a flow rate of about 94%, this gives me good adhesion, minimal blobs/zits, and nice surface quality on the skin layers. But each material will be different so you may have to play with it a bit.

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    Posted · Weird markings on bottom of print

    Thanks for the info.

     

    I reset all the settings to a default medium quality print and it came out pretty good.  I was trying the "ironing" and some other setting changes and that made it worse....

    But,  I keep learning... 

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    Posted · Weird markings on bottom of print

    That model is fine and the bottom is flat.  The issue must be in your settings.

    My Ender doesn't like ironing at 10% flow.  At 7% parts come out very good.  Every printer is going to be at least a bit different.  I print on the Creality glass with the textured surface so the bottoms of my prints always pick up the texture.  

     

    "Also keep in mind Cura likes to put down 120% flow"

    @jirodriguez72 that would be from the printer definition file of whatever printer you have.  Most printer definitions don't call for that even though it is helpful when starting out.  I run my Initial Layer Flow at 105% as it pretty much guarantees a good first layer and takes care of inconsistencies in my piece-of-paper leveling.

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    Posted · Weird markings on bottom of print

    Good Info....thanks

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    Posted · Weird markings on bottom of print

    I have seen this occurring when the extruded "sausages" do not bond perfectly to the glass, or when there is a bit of overextrusion, or the nozzle too close to the glass (so the melt spreads out too far). The sausage is layed down but its edge curls up just a tiny bit. On the next infill pass in the opposite direction, these curled-up edges are remelted and pushed down again onto the bed. If only part of it curls up, and part not, then you could get this effect too. Because the originally layed down sausage and the remelted and pushed down again edge spread in a different way, and overlap in a different way. This happens if bonding to the glass is not equal over the surface. But you have to keep watching very closely while printing, to see it happen.

     

    You can see the effect to a lesser degree in these two prints: a tiny bit in the first model...

    DSCN4938.thumb.JPG.90124a14e04953b171581afa5e8f9e9a.JPG

     

    ...and a bit more in this model. Note: the vagueness and indents are because of tests with solvents that weakened and deformed the model, making the circular indents on the other side shine through.

    greyholes_shinethrough_back.thumb.png.b55cd99467248af1f5ec718083e15138.png

     

    I am not sure it is the same effect in the topic starter's photos, but it could be?

     

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