Calibrating flow for dimensional accuracy

[morgandc]

I am running PETG at 260c on a 65c bed and fans at 50%, I will likely start bringing the temp down. Prints look pretty good, but it was time to try and get more dimensional accuracy. I have run through measuring my filament (1.7272) and then printing the Dimensional Accuracy for deltas square and measuring the width of one layer with a micrometer and averaging the results. I got it down to where the width setting was .55mm and my average was .5515. The problem is that the flow tweak was at .6 and I am severely under filling. I need to get the flow back up to normal while getting the width under control. My initial width was .7087mm with a flow tweak of 1. Factory nozzle on a Max v3, I assume a .5 nozzle since that was all that was made when I ordered it and that is spec'd.

What am I missing? Going to sleep on it, and hit google again in the morning.

Thanks,
-Dwight


EDIT: .2mm layer height.

[Jrjones]

I don't have a V3 with the new extruder, but did you calibrate your steps/mm for the extruder?

[morgandc]

No, but according to the post this procedure will account for that which makes sense. If it was perfectly calibrated the adjustment factor would be 1. If I had a .6 and it produced good results I would then likely go calibrate my steps to get it closer to 1.

[IMBoring25]

The width of the extrusion on the first layer is heavily dependent on the setting of Z=0. I would not consider this a robust method for extruder calibration. It would be closer to right on subsequent layers.

[morgandc]

Pics with average wall width and extrusion factor.

[morgandc]

The measurements were taken 2 each wall, using the top of the wall and avoiding corners. Do you have better option or path to go down? I am trying to avoid customizing the measurements in a cad stl file to make things work.

[morgandc]

If the data seems bad...throw it out and start over

I was using higher temp for "filling" the first layer, so I have gone back to 240c for testing in case layers were sagging. I am also making sure that I am only getting the top layers in the micrometer. So far things are looking more normal. The bottom layer is basically threads but I can likely deal with that on another parameter. We shall see.

[morgandc]

Well, after fiddling all week I have landed on 245c for hot end, 70c on the bed for PETG, and having to readjust my z position. I finally have a good test disk, and am printing a 3DBenchy now hoping it comes out ok. I may need to adjust my fans, they are running at 50% right now. I believe I have been compensating (PLA an PET) for proper z height with excessive temperature. Still learning, and playing with a setting right on top the bed is a little intimidating....but not big deal if you set it via the screen on the machine.