Prusa Bed Leveling 7x7  

  RSS
simone.f
(@simone-f)
Estimable Member

Hello to all,

I've tested today for the first time the Mesh Bed Leveling 7x7.

I've noticed two strange behaviours:

1. During the 7x7 test, it goes fast expect in 3 points, where the nozzle goes up a little more than in other points, why?

2. I've calibrated the bed using Octoprint Prusa Mesh Leveling Heatmap. With 3x3 leveling, my accurancy was near to 0.050mm, not so bad. After switching to 7x7, without touching the bed, the variance went to 0.900mm really high. It's because 7x7 is not supported on the software in Octoprint or why?

Then, what about the settings in 7x7 or 9x9 in the Prusa menu? Cannot find out differences and details on manual. Some hints?

Thanks!

Simon

...
Posted : 18/05/2019 2:59 pm
vintagepc
(@vintagepc)
Noble Member

3x3 interpolates the other points between each measured point; if there are very local highs or lows, you will naturally get a higher variance when you actually measure those values.

Posted : 18/05/2019 3:17 pm
simone.f
(@simone-f)
Estimable Member

Does it then mean that the 0.9 variance then should be corrected? Seems really strange so much difference 🙂

BTW I've not understood wht happens on my 1st question. Why the nozzle has this behaviour on 4 points only. The nozzle goes up-down higher, like something went wrong during calibration... on points 21, 9, 8 and 5.

This post was modified 2 years ago by simone.f
...
Posted : 18/05/2019 3:52 pm
simone.f
(@simone-f)
Estimable Member

So, without touching the bed:

3x3 creates a variance of 0.064mm

7x7 creates a variances of 0.848mm

🙁 😕 

...
Posted : 18/05/2019 3:58 pm
Patrick McNamara
(@patrick-mcnamara)
Estimable Member
Posted by: simone.f

So, without touching the bed:

3x3 creates a variance of 0.064mm

7x7 creates a variances of 0.848mm

🙁 😕 

Same firmware used, I assume?  If you really have a 0.848mm variation, lay a good ruler across your print bed, on edge.  A 0.8mm gap would be easily visible to the naked eye if there is any sort of light source behind it.  Also, make sure there isn't any grit or filament bits in between the bed and the plate.  A small piece of filament could easily cause a small distortion in the build plate, and unless it lined up with one of the sense points for the 3x3, it might not be detected.

This post was modified 2 years ago by Patrick McNamara
Posted : 18/05/2019 8:58 pm
simone.f
(@simone-f)
Estimable Member
Posted by: william.m51
Posted by: simone.f

So, without touching the bed:

3x3 creates a variance of 0.064mm

7x7 creates a variances of 0.848mm

🙁 😕 

Same firmware used, I assume?  If you really have a 0.848mm variation, lay a good ruler across your print bed, on edge.  A 0.8mm gap would be easily visible to the naked eye if there is any sort of light source behind it.  Also, make sure there isn't any grit or filament bits in between the bed and the plate.  A small piece of filament could easily cause a small distortion in the build plate, and unless it lined up with one of the sense points for the 3x3, it might not be detected.

Hello!

Same firmware, yes, just updated yesterday. Well, I was using some washers to create some gap and have fine tuning of the plate. Seems that in one point of the plate, the washer was near the bed instead of far and, seeeeems, that this gives interferention on 7x7. Removing it and placing the gap on the lower side of the 6x6x3b spacers instead of up, removed the interference and the excessive gap... I don't know if that makes sense and if it's the behaviour of my first question. Now the mesh bed leveling is fast and smooth on all points

The variance on 3x3 is 0.032mm and on 7x7 is 0.106mm, much better!

Thanks all for the suggestions!

Simon

...
Posted : 19/05/2019 11:48 am
Share:

Please Login or Register