Bed compensation test?

[FelixH]

Holly Molly @Phaedrux thanks a lot for your comprehensible answer and the time you took...

Both nozzle and bed were at working temperature when measuring the Z-trigger height, but the sensor can have obviously systematic errors nonetheless. I will try to adjust those parameters.

I was aware that the probes are not 100% precise ore repeatable, but I thought 0.5 mm of error with babystepping was way too much, isn't it?

I'll report back asap...

[dc42]

@FelixH, how do you home Z? If you are homing Z using the IR sensor, where on the bed do you do that? The centre of the bed is usually best. It's a good idea to use a point that is also one of the points on the mesh used for bed compensation.

[FelixH]

@dc42 I modified the corresponding .h file (I don´t remember which one it is) so that the Z homing takes place on the center of the bed.

Yesterday I was able to print a Benchy again. But after following all the indications, I still had to put the nozzle down with babystepping by 0.300 mm

[dc42]

@felixh said in Bed compensation test?:

@dc42 I modified the corresponding .h file (I don´t remember which one it is) so that the Z homing takes place on the center of the bed.

Yesterday I was able to print a Benchy again. But after following all the indications, I still had to put the nozzle down with babystepping by 0.300 mm

If you home Z and then send G1 X0 Y0 Z0 with no babystepping active, does it put the nozzle right on the bed surface?

[Hornetrider]

@FelixH

HI
please check your system folder if a "resurrect" file is there. Delete and try again to print...

Cheers

[FelixH]

@dc42 said in Bed compensation test?:

G1 X0 Y0 Z0

If I do a homing on X150 Y150, followed by a G1 Z0, the nozzle lands at a height of 0.15mm. When I send a G1 X0 Y0 Z0, it lands at 0.30mm from the bed. I´m using feeler gauges (I think they are called that).

@Hornetrider there is no "resurrect" folder...

[dc42]

@felixh said in Bed compensation test?:

If I do a homing on X150 Y150, followed by a G1 Z0, the nozzle lands at a height of 0.15mm.

That indicates that your G31 Z parameter is not right. It should land at 0mm.

When I send a G1 X0 Y0 Z0, it lands at 0.30mm from the bed. I´m using feeler gauges (I think they are called that).

Did you definitely load a height map before that, either by running G29 S0 to probe again, or G29 S1 to load the existing height map?

You mentioned Z motors (plural). Are you taking steps to correct them if they get out of sync?

[FelixH]

@dc42 said in Bed compensation test?:

@felixh said in Bed compensation test?:

If I do a homing on X150 Y150, followed by a G1 Z0, the nozzle lands at a height of 0.15mm.

That indicates that your G31 Z parameter is not right. It should land at 0mm.

When I send a G1 X0 Y0 Z0, it lands at 0.30mm from the bed. I´m using feeler gauges (I think they are called that).

Did you definitely load a height map before that, either by running G29 S0 to probe again, or G29 S1 to load the existing height map?

You mentioned Z motors (plural). Are you taking steps to correct them if they get out of sync?

I did not load the map before doing the test. I will try again.
I check both sides of the x axis to check they are at the same height. Perfection is difficult, but they are in the range of 0.05mm max

[FelixH]

@dc42 Loading the bed map, homing Z and going to Z0 leaves the nozzle touching the surface. On X0 Y0 Z0 leaves the nozzle 0.20mm above the surface

[dc42]

@felixh said in Bed compensation test?:

@dc42 Loading the bed map, homing Z and going to Z0 leaves the nozzle touching the surface. On X0 Y0 Z0 leaves the nozzle 0.20mm above the surface

Three possibilities:

1. Height map is not being used because loading it failed. Run m122 and look for "Bed compensation in use:".

2. Height map is wrong because something has moved. Try running bed probing again, then do the same test.

3. Height map is inaccurate because the IR sensor doesn't work well with your bed surface. Try measuring the sensor trigger height at various points and see how consistent it is.

[FelixH]

will do, and report back

Thanks

[FelixH]

So, I measured the trigger height in 5 different points:

Center: 1.540
X35 Y25 : 1.523
X290 Y25 : 1.565
X290 Y290 : 1.543
X35 Y290 : 1.528

My bed surface is GKF, glass fiber or garolite I think it's known by

[Phaedrux]

Garolite is quite shiny and reflective. Perhaps the IR probe isn't performing well with it. Try covering the bed surface with a piece of plain paper to eliminate the shininess and see how the probe results compare.

[FelixH]

@phaedrux I have a Easy Peelzy for the Tornado, I will try that. The surface is BuildTak-like and should be ok, I guess