Chance to disable mmu2 unit?
Hi everybody.
I got the MMU2s since a month but if I have to print with a single filament I find the MMU unit quite inconvenient for an easy print.
I'm a sick lazy and when I find myself with 5 filaments already loaded, I trick the printer loading the filament directly into the extruder and cheating the sensors so i can print with the 6th filament outside the mmu unit.
now. Is it possible to "deactivate" the mmu unit so i can skip the FINDA check and print easy as before without mmu?
RE: Chance to disable mmu2 unit?
Is it possible to "deactivate" the mmu unit so i can skip the FINDA check and print easy as before without mmu?
of course, I mean an alternative to physically disconnect the communication cable with the unit and reflash the printer firmware
RE: Chance to disable mmu2 unit?
you should just be able to unplug both cables going from mmu to mk3 at the mmu side. 2 screws it doesn't take long. I don't mess with the firmware it just works.
I have a Prusa,therefore I research.
RE: Chance to disable mmu2 unit?
As delivered there is no "lazy" way to disable it. As mentioned you need to open physically disconnect it.
I have seen mods where you add an inline switch to the power line. Then you can turn it on and off (while the printer is off) as desired.
RE: Chance to disable mmu2 unit?
Nice! no needs to reflash with the non-mmu2 firmware? (I have mk2.5s)
RE: Chance to disable mmu2 unit?
Nope, no need to reflash anything! All you have to do is disconnect the MMU and your MK2.5S will just act like a normal single-material printer.
RE: Chance to disable mmu2 unit?
But isn't the extruder body of the MK3s different than the MK3s+MMU2s ?
RE: Chance to disable mmu2 unit?
The position and activation mechanism of the IR sensor is different, but functionally for the printer it works the same. So you do not need to reconfigure the IR sensor to have it work like a plain MK3S.
RE: Chance to disable mmu2 unit?
It's going to technically do the same thing, but the IR sensor isn't going to be terribly useful in that configuration.
There are two main caveats to running the printer like that. The first is that the filament sensor will trigger too late to be effective against run-out conditions, since the filament would have to go beyond the Bondtech gears before it realizes that the condition occurred (with the MMU2, the FINDA would normally take up that responsibility). The second is that filament autoloading isn't exactly going to work for the same reason—you'd have to force the filament into the idler for the IR sensor to trip and for the load process to begin (or open the idler door slightly by hand).
The latter is easy enough to work around—just disable autoloading. The only real workaround for the former is to just not let the printer run out of filament. 🙂 You could probably push the remainder of the expended filament through the hotend if you're careful, but the best solution is to just not let the situation occur in the first place.
RE: Chance to disable mmu2 unit?
There are two main caveats to running the printer like that. The first is that the filament sensor will trigger too late to be effective against run-out conditions, since the filament would have to go beyond the Bondtech gears before it realizes that the condition occurred (with the MMU2, the FINDA would normally take up that responsibility).
I'll give you that you can't then eject the remainder. You'd have to feed new filament in until the old is purged (assuming a different color/type). If you are simply starting a new spool of the same type, however, you feed it in and let it go...
The second is that filament autoloading isn't exactly going to work for the same reason—you'd have to force the filament into the idler for the IR sensor to trip and for the load process to begin (or open the idler door slightly by hand).
Auto-loading works perfectly fine and I've done it many times while my MMU was disconnected. If you are having to use force to get the filament into the gears then it is too tight (either release tension or consider printing a new door (what I had to do to get the IR sensor to play nice)). Yes in the normal position it would start the gears before touching them with the filament, but I don't have to have the filament much more than touching them before the motor kicks in and takes it from me.
I agree that in the long term if you are not planning to use the MMU again that it makes sense to modify the extruder to the plain configuration, but for a temporary change (either because you intend to try the MMU again in the future or just want to get back to printing and not have to deal with rebuilding the extruder again right now) leaving the tower in place and simply removing the MMU works perfectly well.
RE: Chance to disable mmu2 unit?
Auto-loading works perfectly fine and I've done it many times while my MMU was disconnected. If you are having to use force to get the filament into the gears then it is too tight (either release tension or consider printing a new door (what I had to do to get the IR sensor to play nice)). Yes in the normal position it would start the gears before touching them with the filament, but I don't have to have the filament much more than touching them before the motor kicks in and takes it from me.
I only really ran into issues when the extruder stepper motor was powered. That said, I was heavily in tweaking mode when my printer was in that state (i.e. taking my R2 MK3 up to almost a complete R4 MK3S, with a Mosquito hotend), so I suspect my e-axis motor was probably powered far more often than it normally would simply due to me manually controlling the e-axis, fiddling, and tweaking things, etc. It was far easier and more consistent for me to just load from the menu than disable the stepper motor to eliminate the drag from the motor gear.
So yeah, YMMV on that point. 🙂
RE: Chance to disable mmu2 unit?
There are two main caveats to running the printer like that. The first is that the filament sensor will trigger too late to be effective against run-out conditions, since the filament would have to go beyond the Bondtech gears before it realizes that the condition occurred (with the MMU2, the FINDA would normally take up that responsibility).
I'll give you that you can't then eject the remainder. You'd have to feed new filament in until the old is purged (assuming a different color/type). If you are simply starting a new spool of the same type, however, you feed it in and let it go...
The second is that filament autoloading isn't exactly going to work for the same reason—you'd have to force the filament into the idler for the IR sensor to trip and for the load process to begin (or open the idler door slightly by hand).
Auto-loading works perfectly fine and I've done it many times while my MMU was disconnected. If you are having to use force to get the filament into the gears then it is too tight (either release tension or consider printing a new door (what I had to do to get the IR sensor to play nice)). Yes in the normal position it would start the gears before touching them with the filament, but I don't have to have the filament much more than touching them before the motor kicks in and takes it from me.
I agree that in the long term if you are not planning to use the MMU again that it makes sense to modify the extruder to the plain configuration, but for a temporary change (either because you intend to try the MMU again in the future or just want to get back to printing and not have to deal with rebuilding the extruder again right now) leaving the tower in place and simply removing the MMU works perfectly well.
I also did the upgrade, but afterwards had second thoughts. I never used my MMU2 but built it all and now I'm selling it on eBay, if anyone wants a fully built MMU2. Anyway, loading is probably BETTER than with other filament sensor solutions. You stick the filament in and then just press on the plastic piece that raises up and it loads. Works perfect every time. It seems like it would work when filament runs out as well but I haven't tried it. I don't feel like taking my extruder apart for like the 10th time, so I will live with it.