First Layer and Extrusion Problems

Veti

@fcwilt said in First Layer and Extrusion Problems:

How can we be sure the pitch is 8mm?

i cant, but there is a very high chance that isnt a M8 metric lead screw.

fcwilt

@Frederik said in First Layer and Extrusion Problems:

is it possible to create a homez.g file where it automatically probes the bed on three points and enable compensation ?

Yes.

But let's get some terminology straight - bed leveling is not homing.

Bed leveling does what the term suggests - it tries to level the bed.

Homing is the process of determining that an axis has moved to some known position "telling" the firmware where the hardware actually is.

Generally you need to:

home Z using G28 Z
level the bed using G32 and a correctly created bed.g file
set the Z=0 datum using a single G30 and the correct position for the probe point
load the height map (if you have created one) using G29 S1

fcwilt

@Veti said in First Layer and Extrusion Problems:

@fcwilt said in First Layer and Extrusion Problems:

How can we be sure the pitch is 8mm?

i cant, but there is a very high chance that isnt a M8 metric lead screw.

Agreed given the 8mm is a common value.

Frederick

Veti

@fcwilt

but you are right.

@Frederik there are several things you have been asked that you have not given an answer to.

Frederik

@fcwilt you are right it was a wrong setting from yesterday. its a normal tr8 4 stop with 8 Lead Spindle

Frederik

i had to test your tips one after the other.... now my z offset is working as it should.

Frederik

my bed.g File at the Moment:

; bed.g
; called to perform automatic bed compensation via G32
;
; generated by RepRapFirmware Configuration Tool v3.1.7 on Wed Nov 18 2020 18:04:17 GMT+0100 (Mitteleuropäische Normalzeit)

M561 ; clear any bed transform

;Probe 3-point

G30 P0 X330 Y240 Z-9999 ; Front Left
G30 P1 X150 Y0 Z-9999 ; Middle Back
G30 P2 X0 Y248 Z-9999 S3 ; Front Right and compensate 3mm

Frederik

and this my actual homez.g File:

; homez.g
; called to home the Z axis
;
; generated by RepRapFirmware Configuration Tool v3.1.7 on Wed Nov 18 2020 18:04:17 GMT+0100 (Mitteleuropäische Normalzeit)

G91 ; relative positioning
G1 H2 Z5 F6000 ; lift Z relative to current position
G90 ; absolute positioning
G1 X200 Y200 F6000 ; go to first probe point
G30 ; home Z

Veti

so run a G32 and then G29 and post the new picture.

fcwilt

@Frederik said in First Layer and Extrusion Problems:

and this my actual homez.g File:

; homez.g
; called to home the Z axis
;
; generated by RepRapFirmware Configuration Tool v3.1.7 on Wed Nov 18 2020 18:04:17 GMT+0100 (Mitteleuropäische Normalzeit)

G91 ; relative positioning
G1 H2 Z5 F6000 ; lift Z relative to current position
G90 ; absolute positioning
G1 X200 Y200 F6000 ; go to first probe point
G30 ; home Z

You can at this point add:

G32
G1 X200 Y200 F6000
G30

The reason for the last two lines is the bed leveling can change your Z=0 datum it needs to be set again - just to be safe.

If you wish to probe at the actual center of the bed you will need to adjust the G1 X and Y values to compensate for the probe X and Y offsets.

To insure that I always move to the same point with I need to do a G30 I have a macro file "centerprobe.g" that contains this:

G90                                                                          ; absolute
G1 Z5 F1200                                                                  ; move to probing height
G1 X{-sensors.probes[0].offsets[0]}, Y{-sensors.probes[0].offsets[1]}, F6000 ; move to bed center for probing

The second G1 command takes advantage of the v3 firmware to access the probe X and Y offset values.

BUT the way my printer is setup the Z axis is already homed whenever I execute this macro so the G1 Z5 command will work.

Frederick

Frederik

@fcwilt ok, i will add these commands

fcwilt

@Frederik

I was editing while you were posting - please check to see if you saw all of what meant to post.

Frederick

Frederik

i am back,

i editet my Files, generatet the macro file centerprobe.g
and insert the additonal G32 in my homez.g

the x and y position is now with the probe offsets the center of my build area.

; homez.g
; called to home the Z axis
;
; generated by RepRapFirmware Configuration Tool v3.1.7 on Wed Nov 18 2020 18:04:17 GMT+0100 (Mitteleuropäische Normalzeit)
G91 ; relative positioning
G1 H2 Z5 F6000 ; lift Z relative to current position
G90 ; absolute positioning
G32
G1 X165 Y187 F6000 ; go to first probe point
G30 ; home Z by True bed leveling 3 points in bed.g

fcwilt

@Frederik said in First Layer and Extrusion Problems:

i editet my Files, generatet the macro file centerprobe.g
and insert the additonal G32 in my homez.g

Given you are new to this I should have mentioned that to use the "centerprobe.g" macro you need to put M98 P"centerprobe.g" into your code whenever you want to move the probe to the center of the bed.

So instead of the G1 command preceeding the G30 you would have M98 P"centerprobe.g" BUT you will need to comment out the G1 line in "centerprobe.g" that tries to move on the Z axis since that line assumes Z is already homed.

Frederick

Frederik

ok thank you, i try it and post the results in a moment

Veti

you should really keep your bed.g and homing files as simple as possible.
then use a macro to combine the actions.

A Former User

Given that it's a core-xy which normally homes one axis after the other (normally x then y) after x homes you can tell x to place the nozzle to the centre of the bed and then home y and again tell y to go to the centre of the bed no extra files or code required then home z can be executed as normal from the centre of the bed

A Former User

; bed.g
;
; called to perform automatic bed compensation via G32
;
G28                         ; Home all
G30 P0 X2 Y-2 Z-99999       ; Probe near the front left lead-screw
G30 P1 X152 Y278 Z-99999    ; Probe near the rear lead screw 
G30 P2 X290 Y-2 Z-99999 S3  ; Probe near the front right lead-screw
G30 P0 X2 Y-2 Z-99999       ; Probe near the front left lead-screw (Second Pass)
G30 P1 X152 Y278 Z-99999    ; Probe near the rear lead screw (Second Pass)
G30 P2 X290 Y-2 Z-99999 S3  ; Probe near the front right lead-screw (Second Pass) 
G91                         ; Switch to relative positioning moves
G1 H2 Z5 F8000              ; Drop the Z axis (the bed) by 5mm relative to its current position
G90                         ; Revert back to absolute positioning moves
G1 X160 Y155 F8000          ; Position the nozzle at the centre of the bed
G30                         ; Probe and set the height as probed
G29 S1 P"heightmap.csv"     ; Load the height map

This is an operational bed.g file for a core-xy with x3 z axis lead screws

Frederik

@CaLviNx THank you i will have a look and adjust mine accordingly

fcwilt

@CaLviNx said in First Layer and Extrusion Problems:

Given that it's a core-xy which normally homes one axis after the other (normally x then y) after x homes you can tell x to place the nozzle to the centre of the bed and then home y and again tell y to go to the centre of the bed no extra files or code required then home z can be executed as normal from the centre of the bed

That is assuming you don't care if the probe is at the center of the bed.

Because I want to probe the center of the bed I created the macro I mentioned which does the math required.

Frederick