The amount extruded can vary a lot, it's pressurising the nozzle prior to printing. If the filament is moist and the hotend has been idle at printing temperature for a while the hotend may have dribbled almost empty, OTOH if just loaded the filament may already be at pressure and the hotend full.
If you need help calibrating the first layer 'Z' offset run the built-in calibration and post a picture of the resulting print *on the print sheet*.
Cheerio,
RE:
I tuned the nozzle temp to 195c, as that seems to be where PLA like to run best through the PCD nozzle. Otherwise, ran calibration as built-in.
I noticed that the actual print started out with a significantly wider bead that thinned out to "as expected". Not sure if that means anything.
Thanks. Brad.
RE: How to set nozzle height for the first layer
Diem,
FYI...
Yes, I see the retraction string trailing away from the test patch. I'm working on that. It is a common issue with these PCD nozzles, due to the extremely low friction they impart. I'm thinking a bit of filament retraction will be in order, as that's the going advice on the issue.
Also, The printer had just gotten done with a small "test" part, but had parked the filament, as it's an MMU machine, and that's just what it does. This calibration test print followed a typical print cycle, so the filament loaded as it is going to with any other print.
Thanks. Brad.
That should print OK 'though you need to clean those fingerprints off the print sheet or you will have adhesion problems.
The mesh bed levelling means that the first layer will not be exactly 0.2mm thick, it will vary as the printer accommodates to any variation in the surface - so measuring this layer is not going to tell you anything.
Dropping the nozzle temperature *might* cause problems with interlayer adhesion; if so, restore the temperature but slow the first layer by 10%-20%.
Cheerio,