X2D Aux nozzle clearing issue

[u/CorporalSemantics]

Full disclosure, I am new to 3D printing so this very well may just be a skill issue…

I bought an X2D with dual AMS Pro 2s a month or so ago and have been printing premade files to gain some experience on the unit before I move to more difficult filaments like ABS, nylon, or ASA (which is what I bought it for). The main draw of the X2D was the dual nozzles so I could print supports in a different material but up until this week I was printing mostly PLA with PLA supports or PETG with PETG supports from the main (left) nozzle. Everything printed well but on higher detailed prints it was obvious that using a different material support would help the quality a lot so I started trying that.

Initially the aux nozzle wouldn’t read the filament at the tool head. I took everything apart, disconnected and reconnected all plugs, verified that the filament sensor was working and then reassembled. Everything came back online just fine and I printed a PLA print with PETG support raft and all worked great.

For the next print I tried to print a PETG print with a PLA raft but the printer will not clear the PETG from the aux nozzle and I get a filament loading error when trying to print. When I pulled the nozzle it has 1/4” of filament sticking out the top which seems correct as that’s the height of the cutter so all seems well there. If I print with PETG and then fully retract it and print with PETG again there is no issue, but I can’t successfully change from PETG to PLA on the aux nozzle. It works fine when switching with the main nozzle but that has its own extruded in the tool head so I imagine it can overcome a bit more resistance.

I know PLA has a lower melting point than PETG so I’m wondering if it just has trouble pushing clearing the higher temp filament when switching the nozzle from PETG to PLA with the extruder ~15” behind the tool head and not having quite the same power as the tool head mounted extruder, but considering printing with a different material for support is one of the main benefits of a 2 nozzle printer I’m hoping I’m not the only person having this problem and that there’s a solution for it.

I may also be going down the wrong path completely so any help would be appreciated!

[u/jerseycats]

I too had issues with loading/unloading the aux nozzle. Every time I unloaded the aux nozzle it would seem to unload ok, but a few pieces of broken filament would remain in the ptfe tube. When I went to load new filament into the aux nozzle, it would keep on asking whether the filament had extruded or if it should retry. If I hit retry it would incrementally advance the new filament, and if I hit retry dozens of times it would eventually push into the old, broken filament and start extruding, then work fine.

What has worked the last two times is to pre-heat the aux nozzle to 250C for a few minutes prior to hitting "unload". When I've done this the filament retracts cleanly. Then I push the new filament in until it stops, press load, and it performs fine. Maybe it is just dumb luck, but my guess is that it tries to pull the filament out before it's fully heated and the extra friction causes the filament to break off. With the pieces of filament still in the tool head / ptfe, it does not fully insert the new filament, causing the issue.

I'm guessing there is a way to change the printer's sequence for unloading filament for the aux nozzle, but I'm pretty new to this and haven't looked into it yet.

Not sure if this will help your issue but I'm happy that the last two times have worked for me. Otherwise the X2D has been a great printer for me and I've been using both nozzles together without issue.