First Layer and Extrusion Problems

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

A Former User

@fcwilt said in First Layer and Extrusion Problems:

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

That is assuming that you DO care that the probe IS at the centre of the bed because you have already told x and y to put the nozzle/probe to the centre of the bed ready for z to home using the probe, this way NO extra macro is required, making it nice and simple.

fcwilt

@CaLviNx said in First Layer and Extrusion Problems:

That is assuming that you DO care that the probe IS at the centre of the bed because you have already told x and y to put the nozzle/probe to the centre of the bed ready for z to home using the probe, this way NO extra macro is required, making it nice and simple.

Except you are not probing the center of the bed which I consider essential.

Frederick

A Former User

@fcwilt

who said you are not probing the centre of the bed?

fcwilt

@CaLviNx said in First Layer and Extrusion Problems:

@fcwilt

who said you are not probing the centre of the bed?

Your example stated that you were positioning the nozzle at the center of the bed, not the probe.

Frederick

A Former User

@fcwilt

With the nozzle you usually have a probe yes? So you place the nozzle/probe at the "centre" ready to probe

I incorrectly assumed that you would manage make that mental connection between nozzle and or probe on your own, apologies for my incorrect assumption

fcwilt

@CaLviNx said in First Layer and Extrusion Problems:

I incorrectly assumed that you would manage make that mental connection between nozzle and or probe on your own, apologies for my incorrect assumption

With most probes it will not be possible to place both the nozzle and the probe at the center of the bed at the same time.

Your example stated you were positioning the nozzle at the center of the bed.

At the position, with most probes, you are not going to be probing the center of the bed.

Frederick

A Former User

@fcwilt

My probe offset is Y0, X-7 on a 500x500mm bed that as near as dammit the centre, centre enough that I wouldn't be pedantic enough to worry about it, and anyway it was just a "generic" term "nozzle" my home.x, home.y & bed.g are suitably adjusted to pedantically place the probe to the bed centre.... with most probes you ARE going to be probing the centre, it is just that the NOZZLE wont be in the centre.

And the key word is "most" precision piezo springs to mind......

fcwilt

@CaLviNx said in First Layer and Extrusion Problems:

You posted an example that stated "nozzle". I therefore assumed you meant "nozzle".

I cannot read your mind and can only go by what you posted.

When trying to help a beginner learn how to do things I think it best to be clear in what you are telling them to do.

Telling them to center the nozzle when you mean probe is not my idea of being clear.

Frederick

Frederik

so, i tried this bed.g:


G30 P0 X330 Y250 Z-99999     ; Probe near the front left lead-screw
G30 P1 X165 Y0 Z-99999       ; Probe near the rear lead screw 
G30 P2 X0 Y250 Z-99999 S3    ; Probe near the front right lead-screw
G30 P0 X330 Y250 Z-99999     ; Probe near the front left lead-screw (Second Pass)
G30 P1 X165 Y0 Z-99999       ; Probe near the rear lead screw (Second Pass)
G30 P2 X0 Y250 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