First Layer and Extrusion Problems

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

Veti

again its not a good idea to do more than it is intended in the bed.g and other config files.

just create a macro that does
G32
G32
G28 Z
G29 S1 P"heightmap.csv"

Frederik

To my setup:

At the moment I use the Bltouch, but I could change the sensor to a capacitive on for testing purposes.

Frederik

@fcwilt you are right, I meant probe. It's all a bit confusing in the beginning

Frederik

@Veti what do you mean with the macros. Do you have for every command an extra makro?

A Former User

@fcwilt said in First Layer and Extrusion Problems:

@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

and still you are pedantically grasping at straws......

if we got it work and being within 10mm of the bed centre, i would call that a result...... and besides the point there is still NO NEED to add a macro to send the "probe/nozzle" to the centre of the bed when you can 100% do it from the home files.

telling a beginner to add unnecessary files in not that helpful..

A Former User

An operational homeall.g to place the head/probe/nozzle (whatever you pedantically wish to call it) in the centre of the bed with NO NEED for a macro

; homeall.g
;
; called to home all axes
;
G91                     ; Switch to relative positioning moves
G1 H2 Z5 F6000          ; Drop the Z axis (the bed) by 5mm relative to it's current position
G1 H1 X-350 F6000       ; Fast travel the X axis close to it's endstop & stop 
G1 H2 Z-5 F6000         ; Raise the Z axis (the bed) by 5mm relative to it's current position
G1 H0 X175 F6000        ; Fast Travel the X axis to the centre of the bed
G1 H2 Z5 F6000          ; Drop the Z axis (the bed) by 5mm relative to it's current position
G1 H1 Y-350 F6000       ; Fast travel the Y axis close to it's endstop & stop 
G1 H2 Z-5 F6000         ; Raise the Z axis (the bed) by 5mm relative to it's current position
G1 H0 Y170 F6000        ; Fast Travel the Y axis to the centre of the bed
G90                     ; Revert back to absolute positioning moves
G30                     ; Raise the Z axis (the bed) and stop when probe is triggered and set Z to the trigger height

fcwilt

@CaLviNx said in First Layer and Extrusion Problems:

and besides the point there is still NO NEED to add a macro to send the "probe/nozzle" to the centre of the bed when you can 100%

Not completely true.

There are other times when you need to set the Z=0 datum such as when creating a height map or loading it.

It is important to use the same probe point. The macro I use insures that the same point is used in every case. There is no chance for a typo or my faulty memory to cause a problem.

Frederick