Unable to get a good result from first layer calibration on Prusa I3 Mk3S
All seems fine up until I try the first layer calibration.
The result is a very loose stringy square simular to the example screen shot saying too high.
I have tried adjusting many time but it seem to have no impact?
When the printer starts to print the zig zag lines I have noticed that the at the start of the first line the filament is twice as thick as the rest of the lines. I do not have any experience to know if this is correct?
I have also tried adjusting the P.I.N.D.A. several times and restarting the calibration with no luck.
Any suggestions please?
Regards Gordon
RE: Unable to get a good result from first layer calibration on Prusa I3 Mk3S
Hi Gordon,
Are you using 3x3 mesh bed levelling where the printer tests nine points on the build plate, or are you using 7x7 MBL where the printer tests 49 points?
if you are not using 7x7, may I suggest that you try it!
have you made sure that your build plate is very clean,
I use hot water and dish detergent, to rub the buildplate really well and remove grease, then I rinse well with Clean hot water, and dry immediately using plain paper towels. only handling the build plate by it's edges. 
also I use the 'Life Adjust 'Z' My Way, process for first layer adjustment, rather than the Prusa tool.
good 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: Unable to get a good result from first layer calibration on Prusa I3 Mk3S
When the printer starts to print the zig zag lines I have noticed that the at the start of the first line the filament is twice as thick as the rest of the lines. I do not have any experience to know if this is correct?
I've seen this too when using the firmware Z calibration. The flow will stabilize as the lines progress and they will assume a uniform size.
RE: Unable to get a good result from first layer calibration on Prusa I3 Mk3S
Make sure the print surface is really clean, then try this...
Also add some pictures, they really help the community.
RE: Unable to get a good result from first layer calibration on Prusa I3 Mk3S
Thank you all, I started again rechecked all the setting's set to 7 x 7 and I'm away, thanks again.
Just ate my last Haribo and printed the frog 🙂
Regards Gordon
RE: Unable to get a good result from first layer calibration on Prusa I3 Mk3S
I've found that I get far fewer double-taps since I changed to 7x7 from suggestions here, and also to five samples.
As far as consistency of the prints, it's really uncertain whether this had any measurable effect, but it sure did not hurt and adds less than a minute to the print start-up, which is tiny compared to the duration of most prints.