What does the first layer check actually do?
I had a feed problem and there was no filament on the buildplate.
the print finished successfully according to the printer.
Neither the spaghetti nor the flow check nor the first layercheck noticed anything.
i had ecpected the first layer check at least to notice that there is nothing on the bed…
(blue abs on textured plate)
I think the first layer check is checking to see if anything is “sticking up” from the first layer. IE that a section of the print hasn’t adhered properly. I don’t think it can check to see if filament isn’t there.
hm, i thought it could even check the line width of the extrution to check the flow.
i guess the real method is kept secret…
A first layer check is one of the most effective tools for identifying flow ratio and most of all, it will reveal a dirty or contaminated build plate immediately. Think your plate is clean? Think again. The first later test will reveal contaminate you didn’t even know were there.
Here’s a demonstration I posted elsewhere. In the example, I did a simple cube primitivize that was 100x100x0.1m. The thin layer height ensures that the slicer will lay down only one line of filament. I deliberately used a smooth plate and just put my finger tips on it. The smooth plate shows the finger print well, something not visible on a textured plate which is why one would be forgiven for believing they have a clean plate when it’s not. On the left is what the first layer test looked like after the print.
And if one had just a small contamination issue, as I did in this test, and failed to properly clean the plate, one could easily believe that there was a problem with the filament or the slicer settings when, in fact, it was just a dirty plate.
A textured PEI plate. Looks clean, right?
Not so clean after a first layer test.
And as mentioned, using a 250x250mm first layer will also confirm that the flow rate is dialed in correctly and reveal contamination at the same time.
It will also show if there is bed leveling that needs to be performed. There should be uniform lines if all is calibrated correctly as one will see deviations from corner to another alerting you to unevenness in the bed level calibration.
