PauseAtHeight: added extrude amount option

[peteruithoven]

See #19
I have not tested this yet with an actual print

[Ghostkeeper]

Typo in the setting key 😉

[peteruithoven]

Just trying to be consistent with https://github.com/nallath/PostProcessingPlugin/blob/master/scripts/PauseAtHeight.py#L38 ;) No just kidding, I should probably fix both.

[Ghostkeeper]

Ah, right, didn't see that.
Fixing both would be nice, though it's not your obligation.

[peteruithoven]

As usual I'm struggling with G-Code, it doesn't seem to extrude the amount I ask it to extrude, even after lowering the feedrate to a normal rate;
2002dc9

The M83 should cause the extrude value to be relative, this is also clearly required for the retraction step. But still it usually extrudes 5 or 10mm when I input 50 for example. I'm distrusted the motor disable (M84), but removing it didn't help. An important piece of that G-Code:

;TIME_ELAPSED:20.878
;TYPE:CUSTOM
;added code by post processing
;script: PauseAtHeight.py
;current z: 1.000000 
M83
G1 E-10.000000 F6000
G1 Z2.000000 F300
G1 X190.000000 Y190.000000 F9000
G1 Z15 F300
M84 E0
M0 ;Do the actual pause
G1 E50.000000 F200
G1 E10.000000 F6000
G1 E-10.000000 F6000
G1 Z2.000000 F300
G1 X111.100000 Y111.100000 F9000
G1 E10.000000 F6000
G1 F9000
M82
;LAYER:7
G0 X111.100 Y111.100 Z1.000

Settings used for this G-Code

• Pause height: 1
• Head park X: 190
• Head park Y: 190
• Retraction: 10
• Extrude amount: 50

[Ghostkeeper]

I think I see what you mean. The problem is that the material is retracted when you try to extrude 50. It'll extrude 40 then, because the filament was 10mm above the nozzle.

What you want is to have the extrude one line lower, between G1 E10.000000 F6000 and G1 E-10.000000 F6000. I don't know why it does that little drop of the material there, but it's not retracted at that point so you can extrude your 50.

[peteruithoven]

Ah because it's at -10 (that 10mm above the nozzle)... Good catch.
I'll try this. But I'm afraid it's not the complete solution, because it didn't seem to extrude even 40mm.

[peteruithoven]

Same result, I see maybe 3mm being extruded with the settings mentioned above.

[peteruithoven]

The G-Code as it is generated now:

;TIME_ELAPSED:20.878
;TYPE:CUSTOM
;added code by post processing
;script: PauseAtHeight.py
;current z: 1.000000 
M83
G1 E-10.000000 F6000
G1 Z2.000000 F300
G1 X190.000000 Y190.000000 F9000
G1 Z15 F300
M84 E0
M0 ;Do the actual pause
G1 E10.000000 F6000
G1 E100.000000 F200
G1 E-10.000000 F6000
G1 Z2.000000 F300
G1 X111.100000 Y111.100000 F9000
G1 E10.000000 F6000
G1 F9000
M82
;LAYER:7
G0 X111.100 Y111.100 Z1.000

[peteruithoven]

After doing another test I realize we'll also need to compensate for the extra extraction in the layers after the pause.

[peteruithoven]

Changing all the extrusion commands after the pause doesn't seem scalable, if anyone has an idea on how I could add extra extrusion without this that would be very welcome.
Ideally I could be reset the extrude amount the firmware thinks it's at, but I don't think that's possible.

[peteruithoven]

@sjoerdtimmer ([email protected]) and I figured out how we could use G92 to reset the E position after the pause to the position it was before the pause. So this seems to work.

It allows extra extruding, before a resume. It still works when someone doesn't change the material, it will just extrude more.

What do you guys think?

[nallath]

Could you remind me to look at this in a few days? Due to the release the 18th we're super busy right now.

[Ghostkeeper]

@nallath Here's a reminder.

[nallath]

Thanks!

Did you guys test both cases?

The code looks fine, so i'm willing to merge it if it's tested.

[peteruithoven]

I totally understand, no problem, great work on the new Ultimaker.

In the mean time I'm still improving this solution. Adhesion is a challenge, especially when using multiple material types, so I'm working on a redo layers setting. This would allow you to redo a number of layers after the pause.

I'm also not sure how to explain that extrusion of 128 is needed, for Ultimaker2's. I'd like to recommend this in the description.

[peteruithoven]

I haven't tested this yet on anything else than a Ultimaker2. Simply resuming, without material change, works fine, it just extrudes extra.

[nallath]

Extrudes extra? Won't that mess up the print?

[peteruithoven]

It's not perfect. It's extruded while the head is this in it's pause location, but it could be pulled towards the print.

[peteruithoven]

It's getting there, my English liquorice. The only black I have is abs (besides hips and colorfabb ht) which makes this print even harder.

[peteruithoven]

I've added a redo layers option to increase adhesion and I've improved the extrude amount description, including the seemingly random 128.

[nallath]

So is it good to merge now?

[peteruithoven]

I think so, but I'm happy to improve it where needed.