I got curious, so I ran a short extrusion of PLA with the stock .50mm nozzle above the bed. I measured it and found that the diameter is around .42-.43 mm. Any thoughts on this? I’m wondering if this info is useful as far as maybe tweaking Repetier to reduce banding.
Hi mpoore,
sorry to say, but that measurement has no real information. The diameter of the extrudate depends on the velocity of the material flowing through the nozzle: you put a certain amount of cm³ per s in, and you’ll get the same volume per time out, just with a different cross-section. If you would have “pulled” more slowly, you’d even get diameters larger than the nozzle.
Cheers,
kuraasu
Thanks for the reply, kurasau. I think I understand what you wrote as far as the diameter varying based upon speed. I’m trying to wrap my brain around why that is, but I can’t dispute it. Regardless, wouldn’t this information be important as it pertains to settings in Repetier and/or slicer or does the software already compensate for the speed of the extrusion knowing that volume will change. For instance, I could see that if you set your nozzle diameter in slicer/repetier/firmware for .50mm, but it is extruding at .43mm at speed, this could increase banding. Perhaps I am misjudging the sophistication of the software.
Of course, if what you wrote is true, it could factor into why printing at a slower speed generally increases print quality. Obviously, there are other factors as well.