mesh bed compensation not compensating

Jayson

@fcwilt look at that. I learnt something new today

; homeall.g
; called to home all axes
;
; generated by RepRapFirmware Configuration Tool v3.1.4 on Thu Oct 29 2020 12:06:14 GMT-0600 (Central Standard Time)



G91                    ; relative positioning
G1 H2 Z5 F6000         ; lift Z relative to current position
G1 H1 X-593 Y616 F10000 ; move quickly to X or Y endstop and stop there (first pass)
G1 H1 X-593            ; home X axis
G1 H1 Y616             ; home Y axis
G1 X5 Y-5 F10000        ; go back a few mm
G1 H1 X-593 F1000      ; move slowly to X axis endstop once more (second pass)
G1 H1 Y616             ; then move slowly to Y axis endstop
G90                    ; absolute positioning
G1 X5 Y5 F12000       ; go to first bed probe point and home Z
G30                    ; home Z by probing the bed

; homex.g
; called to home the X axis
;
; generated by RepRapFirmware Configuration Tool v3.1.4 on Thu Oct 29 2020 18:46:36 GMT-0600 (Central Standard Time)
G91               ; relative positioning
G1 H2 Z5 F6000    ; lift Z relative to current position
G1 H1 X-593 F10000 ; move quickly to X axis endstop and stop there (first pass)
G1 X5 F10000       ; go back a few mm
G1 H1 X-593 F1000 ; move slowly to X axis endstop once more (second pass)
G1 H2 Z-5 F6000   ; lower Z again
G90               ; absolute positioning

; homey.g
; called to home the Y axis
;
; generated by RepRapFirmware Configuration Tool v3.1.4 on Thu Oct 29 2020 18:46:36 GMT-0600 (Central Standard Time)
G91              ; relative positioning
G1 H2 Z5 F6000   ; lift Z relative to current position
G1 H1 Y616 F10000 ; move quickly to Y axis endstop and stop there (first pass)
G1 Y-5 F10000      ; go back a few mm
G1 H1 Y616 F1000  ; move slowly to Y axis endstop once more (second pass)
G1 H2 Z-5 F6000  ; lower Z again
G90              ; absolute positioning

; homez.g
; called to home the Z axis
;
; generated by RepRapFirmware Configuration Tool v3.1.4 on Wed Oct 28 2020 15:43:06 GMT-0600 (Central Standard Time)


G91              ; relative positioning
G1 H2 Z5 F6000   ; lift Z relative to current position
G90              ; absolute positioning
G1 X5 Y5 F12000 ; go to first probe point
G30              ; home Z by probing the bed

fcwilt

@jayson

Thanks.

In your config.g file you have this:

G31 P500 X0 Y0 Z0 ;

What sort of probe do you have? The X, Y and Z values are rather unusual.

Frederick

Jayson

@fcwilt
It's just a little micro switch.

This is a tool changing machine so I gave the probe 0 offset and apply an individual offset to each tool.

It's not all configured yet. I just have one nozzle printing now.

Jayson

@fcwilt
And I should be the one thanking you.

I'm at a loss with this machine. Hopefully someone here can figure out how to make it dance for me

fcwilt

@jayson said in mesh bed compensation not compensating:

@fcwilt
It's just a little micro switch.

This is a tool changing machine so I gave the probe 0 offset and apply an individual offset to each tool.

It's not all configured yet. I just have one nozzle printing now.

So the probe actually triggers at exactly Z=0?

Frederick

Jayson

@fcwilt
The machine homes and probes without a hot end attached then when it starts printing it picks up a tool from the rack and uses that tools offsets.

The nozzle I currently have configured hangs about 11mm below the switch when mounted. So T1 has a -11 mm z offset.

I believe that the e3d tool changer uses a similar method

Phaedrux

@jayson said in mesh bed compensation not compensating:

about 11mm

This is going to need to be quite exact otherwise the nozzle will never touch the bed where you expect. Same goes for the XY offset.

Can you post a photo of your heightmap image?

M376 H10

You might need to eliminate that for now until you get things working and know how quickly you can actually taper off the compensation.

Jayson

@phaedrux said in mesh bed compensation not compensating:

M376 H10

It set at 11.2 mm to make a good section of my bed useable.

I will take out that M376 and see if that helps.

thank you

Jayson

@phaedrux
my bed is a little warped, needs some work but nothing bed compensation should handle it for now.

Number of points: 100
Probe area: 2397.1 cm²
Maximum deviations: -0.270 / 0.581 mm
Mean error: 0.252 mm
RMS error: 0.184 mm

Phaedrux

For such a large bed you may need to increase the point density. 441 is the max number of points and you're only using 100. That can mean a large distance between points where interpolation has to guess what the bed height actually is. Combine that with XYZ offsets that aren't quite accurate and it's going to have a very hard time keeping the nozzle where it's supposed to be.

Jayson

@phaedrux I took out that m376 and now it's working thank you so much!

Its not great but it is actually usable over my whole bed now.

Things are a bit temporary right now as I plan on changing most of this printer. as soon as it can print its own replacement parts I will rebuild it and maybe double my probing points.
I just don't want to wait that long for it to probe....

Phaedrux

@jayson said in mesh bed compensation not compensating:

I just don't want to wait that long for it to probe....

Well if the bed is stable and things don't shift around too much you can save a detailed heightmap and load it instead of probing before each print.

G29 S1 to load saved map.

Jayson

@phaedrux I might try G29 S1 but I have a removable magnetic bed. so if I have to take it off I will probably need to re-probe.

Phaedrux

@jayson said in mesh bed compensation not compensating:

so if I have to take it off I will probably need to re-probe.

Maybe, maybe not. If it registers pretty much the same each time it should be ok. Only one way to find out for sure.

fcwilt

@jayson said in mesh bed compensation not compensating:

@phaedrux I might try G29 S1 but I have a removable magnetic bed. so if I have to take it off I will probably need to re-probe.

I have the BuildTak system and I use the same height map.

I do re-create it from time to time.

Frederick

Jayson

@fcwilt I have the buildtak system. Just have to try it