Mesh bed compensation questions

DerGulli

Hello everyone,

until now my printer is running fine excluding getting my first layer right sometimes.

My idea:

setting up a PINDA including temp compensation and mesh bed leveling.

What i have done:

-Connected the PINDA signal to the Z-probe in (got 5V from the expansion header)
-Connected the PINDA temp sensor to E1 thermistor 2
-Checked the trigger hight according the guides with different probe temperatures and calculated C
-Define my grid
-Defined my homing scripts (homing Z is done at the middle of the bed and with G30 to set an Z0 datum)

This is what i set up in my config:

Z-Probe
M308 S2 P"e1temp" Y"thermistor" T100000 B4138 A"Probe" ; Configure extruder 2 temp input as thermistor on pin e1temp PINDA
M558 P8 C"^zprobe.in+zprobe.mod" H3 F120 T10000 ; set Z probe type to switch and the dive height
G31 P1000 X24 Y-21.5 Z1.260 H2 S25.4 C0.00758 ; set Z probe trigger value, offset and trigger height
M557 X34:186 Y31.5:174.5 P3 ; define mesh grid

homing scripts and complete config g attached

No comes the point I don’t understand.

When doing my mesh compensation, I receive different outcomes.

The height differences between the probe points stay the same but the initial point the height map is built from varies.
When I got the version with initial point I probed my Z0 datum (this is also the point I home and set my trigger height) the print runs perfectly. If I got the other versions the nozzle height is off….

As i understand the Z height in the map should be close to zero where the nozzle was homed.

Good version: (homing point marked with the cursor)

Wrong version:

I tried different ways to generate my map but i cannot find a pattern that is reproducible.
1.
G28
G29

G28
G30
G29

G28
Home Z
G29

Your help is appreciated! Please tell me just that I’m thinking wrong and messed it up

Greets DerGulli

p.s. please be patient as im new with reprap (;

Files:
homez.g homey.g homex.g homeall.g config.g

DerGulli

Forgot:

I am printing with:
-duet wifi
-RepRapFirmware for Duet 2 WiFi/Ethernet 3.1.1 (2020-05-19b2)
-Version von Duet WiFi Server: 1.23

Greets

Phaedrux

Have you tested the repeatability of your probe by doing repeated G30 S-1?

DerGulli

Yes i did,

and it looks kinda wired to me. If i do it always at the same spot the readings are nearly 100% accurate but after moving the printhead and poing back to the same position it can happen that the distance changes.
I am really tired about this and i tried a lot.
I think i just try an bl touch as i have some laying around.

Greets ther gulli

Phaedrux

@DerGulli said in Mesh bed compensation questions:

If i do it always at the same spot the readings are nearly 100% accurate but after moving the printhead and poing back to the same position it can happen that the distance changes.

Sounds like backlash to me.

DerGulli

Hi,

thanks for your thoughts, never tought about that. Today i will give it a try with the bl touch. I checked the mechanics and it looks "ok". If all not helps i will order an anti bachlash nut and try again.

Best regards

DerGulli

DerGulli

Hello,

just installed by Bl Touch, my leveling now is consistant. Maybe by sensor had some issues.

Thanks

Greetings DerGulli

Phaedrux

@DerGulli said in Mesh bed compensation questions:

Maybe by sensor had some issues.

I'm not familiar with PINDA enough to say, but glad to hear you're getting good results with the BLTouch.