Just remove the gcode in the End Gcode file if you don’t want it to unload.
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The tube going to the print head should be air tight no? If not, not much air should enter?
Which part of the gcode needs to be removed?
Extruder is not airtight, filament buffer or AMS hub on back of the printer is not airtight too. As tubes have open ends air can freely get in, 2.5mm tube inner diameter allows air to freely circulate.
If you do not unload, the inner volume of the tube is filled with the filament?
Yes, the filament remains in the system. This could be usefull if you want to continue with another print with the same filament. The requested feature is not available. What I usually in that case is, I stop the print at the end via the red button at top of the printer. In that case filament remains within the system.
@leenanj KIndly advise or show the gcode as it should look like based on your proposal.
I know that this feature is not available, I‘m the one who did the feature request. My point is that if you would leave the filament inside the tube, only little air would enter.
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First of all quite a bit of air will enter. Secondly there is a fully exposed part in the middle. In case of nylon and PETG you will have like a meter of garbage filament after a few hours. In case of PVA, it will clog the system. In case of quickly running another print not unloading the filament is useful. However the way how it operates is the safest and with not too much downsides.
I understand, but still it is very annoying. For small parts the X1 is not really faster than my ancient Ultimaker. Why? Because it wastes so much time with doing unnecessary things such as unloading, calibration after every print and so on.
Approx. 7 mins are wasted? For 20 min prints this is a big deal!!
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I think the best solution would be if the user would have a choice at the end of a turn. Respool the filament back into the AMS as you know you will anyway need another color/material or because you will not printing soon again.
If you decide against it and made it smart you could start the next print almost immediately without the additional purge waste in the beginning.
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Replace the End gcode with this, no AMS unloading after print is done.
;===== machine: P1P ======================
;===== date: 20230416 =====================
; My modifications:
; Move M400 command so nozzle not sitting on print
; Remove AMS unload after print job done
G92 E0 ; zero the extruder
G1 E-0.8 F1800 ; retract
G1 Z{max_layer_z + 0.5} F900 ; lower z a little
M400 ; wait for buffer to clear
G1 X65 Y245 F12000 ; move to safe pos
G1 Y265 F3000
M991 S0 P-1 ;end smooth timelapse at safe pos
M400 S2 ;wait for last picture to be taken
G1 X65 Y245 F12000
G1 Y265 F3000
M140 S0 ; turn off bed
M106 S0 ; turn off fan
M106 P2 S0 ; turn off remote part cooling fan
M106 P3 S0 ; turn off chamber cooling fan
G1 X100 F12000 ; wipe
M104 S0 ; turn off hotend
M400 ; wait all motion done
M17 S
M17 Z0.4 ; lower z motor current to reduce impact if there is something in the bottom
{if (max_layer_z + 100.0) < 250}
G1 Z{max_layer_z + 100.0} F600
G1 Z{max_layer_z +98.0}
{else}
G1 Z250 F600
G1 Z248
{endif}
M400 P100
M17 R ; restore z current
G90
G1 X128 Y250 F3600
M220 S100 ; Reset feedrate magnitude
M201.2 K1.0 ; Reset acc magnitude
M73.2 R1.0 ;Reset left time magnitude
M1002 set_gcode_claim_speed_level : 0
M17 X0.8 Y0.8 Z0.5 ; lower motor current to 45% power
Just my two cents for what it’s worth. If someone is wanting to leave the filament loaded because
-
They are printing almost continuously with that filament.
-
30 seconds extra at start up is costing them enough downtime/money to be an issue.
-
The cost of purging a inch of filament is breaking the bank due to exorbitant material costs.
I doubt the filament in the tube is going to be stationary long enough to cause a failed print.
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Yes. Please make this an option!
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Looks like a duplicate of:
Feature Request - Option to keep filament loaded in AMS - Bambu Lab Software / Feature Requests - Bambu Lab Community Forum
Purge a little first. if your worried about moisture. But i live in a very humid place tropics and have no issues with it being in the tube. I will often manually load filament and leave it while i prepare other machines and stuff. This machine can be a total procrastinator screwing around winding unwinding cutting, purging, “calibrating” levelling, scanning, etc etc etc. Any amount of time saved and material not wasted is a benefit to me honestly.
Yes please, do this optional.
Same for me. Printing with the same filament most of the time.
I have been searching for this option some time and couldnt belive that is not implemented.
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Still not an option for this?
The retraction of the filament into the AMS is defined in the g-code in the Printer setting → Machine G-code → Machine end G-code.
There is a section which begins with a comment: ‘;pull back filament to AMS’
; pull back filament to AMS
M620 S255 ; **begin tool change**
G1 X20 Y50 F12000 ; **move and cut filament**
G1 Y-3
T255 ; ** do tool change**
G1 X65 F12000 ; **move over poop chute**
G1 Y265
G1 X100 F12000 ; wipe
M621 S255 ; **end tool change**
M104 S0 ; turn off hotend
2 Asterix comments are my understanding for what happens, without any warranty.
If you want, you can try this:
; pull back filament to AMS
;M620 S255 ; **comment out**
;G1 X20 Y50 F12000 ; **comment out**
;G1 Y-3 ; **comment out**
;T255 ; **comment out**
G1 X65 F12000
G1 Y265
G1 X100 F12000 ; wipe
;M621 S255 ; **comment out**
M104 S0 ; turn off hotend
or the following version, which you can turn on or off:
; pull back filament to AMS
{if notes== "1"}
M620 S255
G1 X20 Y50 F12000
G1 Y-3
T255
{endif}
G1 X65 F12000
G1 Y265
G1 X100 F12000 ; wipe
{if notes== "1"}
M621 S255
{endif}
M104 S0 ; turn off hotend
To turn retraction to AMS on: put a 1 into the ‘Notes’ field in the process settings.
To turn it off put a 0 into the field.
Use on your own responsibility.
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I would also like this feature.
We have an option for bed leveling which allows me to choose when it’s appropriate, such as when using materials with different bed temps. While there are great points above that the default option should be that it retracts to prevent moisture sensitive materials from deteriorating, this option would allow us to save time and material in the very common situation where we are printing consistently with the same material. Making this a checkbox option feeds is consistent with allowing more advanced users to determine the workflow that is best for their situation.
Here is a guide from the bambulab wiki, so this might be the (officially) best way.
If you want to do it with gcode, i would suggest to check that your solution matches with this guide.
(Ill think about it but i dont want to tinker and just focus in my prints and change the color more or less often to mind that for every print.)
https://wiki.bambulab.com/en/ams/manual/ams-not-unloading-to-save-filament
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nice find 
Bookmarking this for later