Simultaneous retraction from multiple extruders: how to do it?
Hi everybody,
I am the owner of a Geeetech A30T, 3 bowden extruders 1 nozzle.
In order to improve the stringing issues, I'd like to have all three extruders to retract at the same time, even when printing with one extruder only.
Reason behind this is that -I think- retraction of only one filament is not enough to handle the mass of melted filament in the chamber.
Is there any setting in Prusaslicer which allows this? or can you suggest any script which allows to adapt the G-code accordingly? Unfortunately, the retraction movements are not easy to identify in the G-code at macro level
Please bear with me if this is a silly question, I'm a real noob.
Thanks!
RE: Simultaneous retraction from multiple extruders: how to do it?
Hi Eddo,
to the best of my knowledge you can only retract the filament that is active at the time,
If you could retract all three at the same time, then you would also have to detract them when you start printing. otherwise the filaments would slowly unload whilst they were not printing...
If you jiggle round with all filaments it is likely that you will pollute the active colour and mess up the results.
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Simultaneous retraction from multiple extruders: how to do it?
@joantabb
Thanks Joan,
I was thinking of retract/deretract, sorry for not being clear.
This is already happening when you use multiple filament (the point of a mixing hotends), I was thinking of controlling retraction and deretraction on the other nozzles even if they are not extruding.
Mixing chambers have lot of issues with stringing, as I suppose the volume retracted is not enough to block oozing due to the viscosity and elasticity of the filament (I suppose the volume of retracted filament is mostly compensated by the stretching in the idle filament ends).
Things are proportionally worse at high temperatures.
I have tested increasing acceleration but it's not helping much - I think it depends on the length of the bowden in the large printers (PTFE tube 70 cm long).
I thought spreading the strain on the three etruders could fix the stringing issues on these printers .
Doesn't it make sense as a feature request?
Your thoughts, please - I wouldn't like to bother the developing team with silly requests 😊
RE: Simultaneous retraction from multiple extruders: how to do it?
If you jiggle round with all filaments it is likely that you will pollute the active colour and mess up the results.
I agree, I see that as a option which can be set up in the configuration.
Currently the only choice is accepting stringing and having "pure" colors, but -for instance- if you are printing only one color or similar hues, you could fill the three bowden with the same color and get hopefully the same performance as a mono color printer.
And accept stringing or color poisoning in the remaining cases.
If I had to develop it, I would make it "tunable" to set the percentage of retraction on the inactive extruders so that you crank them up only as much as it is needed to support the extruding one.
RE: Simultaneous retraction from multiple extruders: how to do it?
to the best of my knowledge Eddo, the three into one nozzle mixes by injecting small proportions of two or three filaments into the common chamber, and relying upon the resultant extrusion, mixing the colours as they are constricted from filament size, to nozzle size.
Which is fine, if you want a mixed colour, but a bit restrictive if you want a pure colour.
as far as I am aware, the pressure of the active filament is supposed to prevent the other colours leaking.
Regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Simultaneous retraction from multiple extruders: how to do it?
as far as I am aware, the pressure of the active filament is supposed to prevent the other colours leaking.
Well if it were like that the retraction of just the active filament would ensure some leaking in the others, and it would be an additional reason to perform simultaneous retraction... Anyway, I'll try to post a feature request in github, Thanks!
Cheers
RE: Simultaneous retraction from multiple extruders: how to do it?
Feature request added https://github.com/prusa3d/PrusaSlicer/issues/5355