First layer problem only with circles  

Yur pictures are not quir sharp enough to be sure but your first layer may be a bit low, too much squish, and there is something on the print-sheet - smears? debris? that may be interfering too. 

A thorough clean of the print-sheet and revisiting your first layer 'Z' calibration should fix it. 

Cheerio,

RE: First layer problem only with circles

The print sheet is clean.  I used dish soap recently and use IPA (91%) in between uses.  I think that is just an artifact of me cropping out the rest of the picture which zoomed it in.  I can try and take a closer picture.

I will re-do my 1st layer calibration, but those have been coming out perfect.  The only time I get these artifacts is when it is trying to print circles (it seems).  Is 1st layer calibration impacted by the shape? 

RE: First layer problem only with circles

Try printing this calibration pattern, it helped me dial my first layer in perfectly. You can gradually adjust the value until it looks right. https://www.printables.com/model/251587-stress-free-first-layer-calibration-in-less-than-5

Is 1st layer calibration impacted by the shape?

If adhesion is low, for whichever reason, it's more likely to pick up on the curve.

Cheerio,

RE: First layer problem only with circles

Posted by: @gilesjuk

Try printing this calibration pattern, it helped me dial my first layer in perfectly. You can gradually adjust the value until it looks right. https://www.printables.com/model/251587-stress-free-first-layer-calibration-in-less-than-5

Thanks. I was using that to adjust my first layer and agree its a nice design to use.  I am now starting to think my mesh bed just isn't level.  I printed the bed level test and in the same corner (and some others) I have issues where as the middle is fine. 

RE: First layer problem only with circles

One thing I recently learned is that you can lower the Z until you get some "waviness" in the top surface as you shine a light at it. This waviness indicates you are a bit too low and to back off. This is a great indicator to help really tune that first layer and helped me a lot to get the Z as low as possible but not too low. I haven't used a 0.6 nozzle so don't have any experience with that size.

This article might help - use with caution.

https://help.prusa3d.com/article/bed-level-correction_2267

Cheerio,

RE: First layer problem only with circles

You also might want to consider physically leveling your bed. There are some good bed visualizer plug-ins for Octoprint and a good bed mod that uses 3ID x 7-8OD silicon tubes to replace 8 standoffs underneath the HeatBed. I just got my tubing and plan to do it in the next few weeks. Requires a new z calibration and setup but gets you really flat. Bed Level mod

RE: First layer problem only with circles

Thanks.  I didn't know about that mod.  So I ended up doing the nylock nut mod.  That made my bed a lot flatter but didn't fix the entire problem.  I ended up cleaning the bed with acetone which fixed some bed adhesion issues I was getting in the corners.  

I will say, I do after doing this question the accuracy of the bed leveling sensors because when I was running this test in places like the back center I would have a layer that was separated and the plugin was telling me to tighten the back center which I think would make it further away from the nozzle. 

I do think I am at a point where it should be functional across the entirety of the bed.  

Posted by: @crab

You also might want to consider physically leveling your bed. There are some good bed visualizer plug-ins for Octoprint and a good bed mod that uses 3ID x 7-8OD silicon tubes to replace 8 standoffs underneath the HeatBed. I just got my tubing and plan to do it in the next few weeks. Requires a new z calibration and setup but gets you really flat. Bed Level mod