I am using a micro-swiss flowtech hot end on my Bambu Lab X1C to easily switch between a 0.2 and 0.4mm nozzle. This time when I swapped the 0.2 Nozzle out I forgot to extrude the leftover filament in it. See image attached.
What is the smartest was to clean out the nozzle? I am thinking of just swapping it back in and then extruding, hoping that the pressure from the new filament will push the old filament out, but before doing so I wanted to ask you guys just to be sure.
I would restore the nozzle to original configuration, load it back in to the printer, and manually load/extrude filament through it to remove the old filament.
Is there a reason why you’re not just doing that anyways? I’m pretty sure the X1C printer always assume there’s old filament left in the nozzle anyways, thus always extruding filament with the new selected filament upon start of the print.
Yeah, the X1C (or any other of the BBL printers that can use an AMS with at least one extruder) has to purge the old filament from the nozzle on every filament switch. No different from this situation.
When you remove the nozzle, there’s filament in it no matter what. Maybe it’s the right filament for the next print you’re going to do, maybe it isn’t. If you were swapping actual BBL nozzle assemblies, you would have the same situation.
Always purge when loading a new filament = it doesn’t matter what filament was there before.
Hold the nozzle with pliers and gently heat using a BBQ lighter, then use a 1.5mm Allen wrench to push the filament through the nozzle. Leave the wrench in the nozzle when it bottoms out, let it cool completely, then you can pull it out and it will take any residue that’s left in the throat out as well.
This right here is a great idea!
Ok first I’m gonna try just swapping the nozzle back in and extruding the leftover filament the regular way. Wasn’t sure if that is the right procedure or if it might break something but it seems to be legitimate.
If this does not work, I will proceed with the lighter + allen wrench method.
rather than a lighter, you could use a heatgun , with adjustable temp
This is a solution in search of a problem. 
Every nozzle comes off a Bambu printer with filament still in it. Every nozzle comes off of every 3D printer with filament still in it (unless you do a cold pull for some reason, before removing the nozzle). There is no way to drive filament out the front of a nozzle without stuffing more filament in to the back of the nozzle.
What’s in the nozzle when you put it back on the printer doesn’t matter, because the printer is going to purge the nozzle with new filament before it starts printing. Same as if you hadn’t removed the nozzle and just switched to a new filament.
So there is no need to remove filament that’s still in a nozzle when the nozzle is removed, nor is there any value to be had in doing so. It literally does not matter.
I would just like to know why this is being performed to begin with, what’s the reason behind removing the nozzle and then trying to remove the cold filament from the nozzle. I don’t know much about aftermarket hotends, so I’m curious about this.
You seem to not be aware of how cut + punchdowns work.
Why are you not doing this?
Filament is always left in the nozzle due to how 3D FDM printers and their nozzles work.
Each time you swap any nozzle the filament in the nozzle will remain as there is no means to push it out on the printer without force. That force is more filament, so you always have filament.
Any filament currently in the removed nozzle will be pushed out the next time you go to print, thus is automatic.
I understand your nozzle isn’t standard, but I am unsure why this would factor into the equation.
Maybe I am miss something, but if this nozzle must be free from filament while at rest, the manufacturer would have provided detailed instructions on how to achieve that endeavour.
Perhaps you could enlighten us…
Not sure what CarbonForge is thinking. His comments are completely unrelated to the subject of this thread… non-sequitur.
Cut and Punchdown relate to modeling in the slicer and have nothing to do with filament in the extruder. Which, BTW, will always have leftover filament in it when you remove it from your 3D printer. No matter how much cutting or punching you do.
You said that every nozzle comes off every printer with filament left in it. That isn’t accurate.
One strategy that is used to reduce purge volume at the beginning of a print or during a color change is to use a cut and punchdown strategy to reduce the residual filament left in the nozzle. The printer cuts the filament, retracts the feed filament slightly, moves over the purge chute, then uses the feed filament to push the stub of cut filament through the nozzle and then quickly retracts the feed filament before it begins to melt.
This reduces that stub of filament in the nozzle, so when it’s time to load a new filament there is less material left in the nozzle to mix with the new filament, so it requires less volume to be purged.
Cut and punchdown.
I don’t recall who, but there is at least one manufacturer that does this by default, and there are customizations available for Bambu X1/P1 models that do this, too.
To your claim that this is a nonseuqitur, that’s wrong, because when cut and punchdown is used, you don’t get nozzles with filament left in them.
Post a link to your reference source, please.
Since you use an aftermarket hotend, others may not know how it is supposed to work. Before this time, what have you been doing to “extrude“ the leftover filament out when swapping the nozzle?
Are you contributing that the exception to the rule which you can’t name helps the OP in anyway?
If there is one in a works of hundreds, it is a rounding error and nit related to the problem seeking an answer.
Adding it for context would have bee, pitched as helpful without the context as you originally did helps no one.
You could have pitched the point as the follows:
While not related to the OPs problem and nit a solution, there is at least one printer o remember learning about (sorry, I can’t remember the name or manufacturer) uses a technique call cut and punch down.
This cuts the filament at the end of the print and uses some method to push the filament out, this is unrelated to the heating element.
Thus is not a feature of Bambu Lab printers, which is why it is not directly related to your question.
Do not feel slighted by this response, it is designed to help others think how to introduce interesting, but not directly related information.
I often use the phrase (or similar) at the top of my non-answer information posts.
Thus does not answer the question p, just something related.
I think I understand the concept that CarbonForge is describing. Cut the filament, but then drive the cut end in to push additional filament out of the nozzle, and then retract the cut filament before it’s melted.
Assuming that’s correct, it doesn’t really do anything more than just cutting the filament. If the after-it’s-been-cut push goes past the heat break, the filament will quickly melt. So the idea, it seems to me, only works as far as the heat break. You have less of the old filament in the nozzle, but the nozzle is still loaded with old filament. Less, but not none. Why bother?
Again, it’s important to keep in mind that left over filament in a nozzle you remove is not a problem that needs to be fixed. Especially for a filament switcher like a Bambu, there is an implicit purge of the nozzle on every switch anyway. Put the nozzle back on, old filament gets pushed out as part of that default purge operation. Regardless of how little or how much old filament there was in the nozzle to being with.
OP indicated they’re using an aftermarket hotend system and have to (in their mind) remember to extrude the old filament each time - we can only guess as to their reasoning. Implementing a cut and punchdown would solve this issue permanently for them. I’m not debating OP’s original assumptions, I’m just presenting a possible solution.
Listen, this isn’t my idea, I’m not married to it at all.
But you’re not really thinking it through all the way when you’re saying it’s pointless, either. Bambu printers don’t cut at the hot zone, they cut above the heat brake. A stock nozzle has approximately 1.5” of filament in it after a cut ordinarily. ANY reduction in this amount of filament left behind is going to mean a reduction in how much purge is needed when color changes are happening.
Anyhow, here’s at least one implementation of this, taken from the Leckiestein discord:
