First and top layer awful !
Hello makers
I've a big problem with my first layer, it looks like that :
there are waves on the surface.
PEI sheet OK, cleaned with dish soap & acetone, the printer is new (1 month)
The back when finished :
the top layer (look at the grey), no wave but strange lines
Grey Prusament filament supplied with the printer
Can you help me ? some ideas are welcome. I have tighten or loosen some crews, checked belts, but I don't know from where it can comes.
Thanks for your help
Sébastien
RE: First and top layer awful !
Hi Herman,
Looking at your pictures,
1, the Build plate appears to be smeared with something shiny. does it change appearance if wiped with a dry paper towel?
2, your first layer appears to be extruding badly, as if new lines of filament are pushing previous lines out of the way, causing ripples.
3, your top layer appears to suffer from varying extrusion,
4, you don't give any details about the printer firmware, Slicer, slicer settings, filament type or temperatures.
what would I do?
a, re wash the build plate with Dish Soap and water, rinse well with fresh hot water, dry with plain paper towels handling the build plate only by the edges. (I Would not use ANY other surface preparation). 
b. I would ensure that 7x7 mesh bed levelling is activated, so that mesh bed levelling senses 49 separate points on the build plate at the beginning of the print.
c, I would re check live adjust 'Z' using the 'Life Adjust 'Z' My Way ' process
https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-assembly-and-first-prints-troubleshooting/life-adjust-z-my-way/
this should help you get your first layer sorted out (It looks to me like your nozzle is too close to the build plate, for the first layer ).
Once the first layer is looking good (Smooth Surface on top and peels off the build plate as a single sheet when removed)
d, measure your filament diameter at several points and at 90 degrees at each point to see of the filament is the correct size and circular. and ensure that your slicer is using the correct value for filament size
Assuming you are using Prusa Slicer, select a suitable profile,
e, I typically use Generic PLA, or Generic PETG etc. make sure that the extrusion multipilier is set to 0.95 , if using PLA, set the bed temperature about 65 to 70 C, and the Retractions, to 0.4...
consider using Octagram Spiral, for the top infill.
this will give your top layer, an interesting texture... 🙂
and have another go...
best of luck,
Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: First and top layer awful !
Make a new first layer, after cleaning sheet, and make a picture. You are also possible to low, then the nozzle pushes filament from the bed.