# Patchy first layer on glass bed

The part at the front has only one layer, and has what appears to be uneven patches. The part at the back has had two layers, so it clears itself up.

The build plate is flat, and level (I levelled it before the print) and by the way the patches are all together I think I can rule out flow issues.

What is going on, and is it a problem? See the image below, for an example:

### Setup and configuration:

• Sheet glass bed
• White PLA (Geeetech from Amazon) - opened the same day
• 190 °C nozzle, 55 °C bed
• Ender 5 printer, with Cura 4.6 slicer

I have changed the filament (still PLA), re-levelled the bed, and here is the bottom of a large flat surface:

Also the top surface has 'ringing' artefacts (I think that is what they are called?):

• Maybe the nozzle is a little too close to the bed. Maybe it begins filling a "patch" (or area) well, but because of being too close or a little over-extrusion the pressure builds up and generally deposits more filament, if it then moves to the next "patch", the pressure relaxes, and starts correct again. Cura has a marketplace with plugins, you could try increasing the nozzle to bed gap with the plug-in from "fieldofview" called "Z offset".
– 0scar
Jul 15 '20 at 21:57
• @0scar that's a great idea! I am going to try levelling again, and maybe changing the nozzle. It's a bit old I have lots of spares. Jul 16 '20 at 6:49
• @0scar, just updated after some more prints. What do you think? Jul 30 '20 at 8:15
• It is difficult to see, but I think it is still a little too close judging the bottom image. But I noticed the bottom layer image, that suggests that the nozzle isn't too far from the bed...
– 0scar
Jul 30 '20 at 12:37
• It is pretty difficult to see, I would download the "Z offset" plugin from FieldOfView from the Cura marketplace and experiment. You can also play with redefinition of the Z=0 in your start G-code; move with G1 Z0.1 and then G92 Z0.
– 0scar
Jul 30 '20 at 17:19