MMU finally coming
So I noticed this morning with the latest updates to the shipping info that it looks like Prusa is finally catching up with orders and to complement that I just received a shipping notice from them.
Unfortunately this kinda complicates things for me as I've been on the fence about if I still wanted it or not. I had been assuming that if I went ahead and waited it out that I could turn around and sell it for cost to someone that didn't want to wait. If they are catching up now though...
I'm on the fence as I am a new user (ordered both the printer and MMU early Dec) and I have learned a lot since I got the printer (mid Dec). Regarding the MMU I've learned that it's not as user friendly as the printer itself and turning single colored models into MM models is not a simple affair. It also appears that I'd lose functionality (e.g. I've had it doing 0.05 layer prints for the last month and a half which as I understand is not supported with the MMU).
To complicate things I also just ordered (expecting to have to wait another few months for the MMU) parts to tweak my extruder (butterworth) to see if that helps a feed/jam issue and also to implement the bearing upgrade for the filament sensor.
With the switch to the bearing mod I have no interest in the MK3S upgrade which reduces functionality. I know switching to the MK3S is part of the MMU2S upgrade though which is supposed to improve MMU usability.
So my questions:
1) Is there still (if so, how much longer do you think) a market of people that want to skip waiting for the MMU?
2) Has the S upgrade improved the easy of use of the MMU? I've loved how easy the MK3 has been to use, but the last 2 weeks that I've been fighting a jam issue really reinforce that I don't want the MMU to turn this into something that frustrates me out of using the printer at all.
3) Is it possible to use the MMU2S with the older (modded) filament sensor? Note that this option does not require a firmware change unlike some.
Re: MMU finally coming
I'm sure you would still be able to easily sell it to someone that wants it "now" for cash instead of ordering and waiting for it to ship. Though you might have to take a small loss if they catch up enough that there is no longer a backlog; I don't think the warranty transfers from original owners... would be something to know before selling or buying. You'd otherwise be competing pricewise to the same thing with a full warranty and only a few days wait.
I can't speak to 2 as I don't have an MMU2 (yet...?), but the answer to 3 is no, as the new sensor design is a key part of the MMU2S - it helps the MMU see when the filament has reached the extruder gears, and this means it's no longer required to calibrate the loading length for each spot on the MMU2.
Re: MMU finally coming
I can't speak to 2 as I don't have an MMU2 (yet...?), but the answer to 3 is no, as the new sensor design is a key part of the MMU2S - it helps the MMU see when the filament has reached the extruder gears, and this means it's no longer required to calibrate the loading length for each spot on the MMU2.
Wouldn't the old sensor (when functioning correctly) tell it that?
I know they switched to the new sensor as it is supposed to be more reliable (without modifications), but I'm definitely in the camp of being irritated by the loss of jam detection (I did have to turn the sensor off, it jammed, but kept running for another 8 hours until I woke up and found it. The print would have still been a loss (based on what I had to do to unjam it), but it would have been nice to not having it running pointlessly for 8 hours...).
Guess I need to do some fast and hard thinking...
Re: MMU finally coming
I can't speak to 2 as I don't have an MMU2 (yet...?), but the answer to 3 is no, as the new sensor design is a key part of the MMU2S - it helps the MMU see when the filament has reached the extruder gears, and this means it's no longer required to calibrate the loading length for each spot on the MMU2.
Wouldn't the old sensor (when functioning correctly) tell it that?
I know they switched to the new sensor as it is supposed to be more reliable (without modifications), but I'm definitely in the camp of being irritated by the loss of jam detection (I did have to turn the sensor off, it jammed, but kept running for another 8 hours until I woke up and found it. The print would have still been a loss (based on what I had to do to unjam it), but it would have been nice to not having it running pointlessly for 8 hours...).
Guess I need to do some fast and hard thinking...
unfortunately not; the new IR sensor is relocated for an MMU setup (from a similar location to the laser sensor to an arm off the access door)so that it is triggered by the shift in the bondtech gear door as the filament goes between the gears. There is no current way to relocate the old laser motion sensor to do the same thing.
Rumour has it jam detection has never worked reliably (as evidenced by your message) so it's probably not as big of a loss as it seems to upgrade to 3S.
My laser sensor's been okay so I opted to do an indirect modded 3S extruder design instead.
If you really don't want your MMU and don't want to think about it anymore I can help make your problem go away for free... 😛 
Re: MMU finally coming
Rumour has it jam detection has never worked reliably (as evidenced by your message) so it's probably not as big of a loss as it seems to upgrade to 3S.
No it's worked pretty good for me. In that case I had to turn the sensor off for a yellow filament it didn't like and then forgot to turn it back on for a subsequent print. In my more recent jam issues where the sensor has been on it didn't stop it immediately, but it would catch it within an hour or so which is much better than running for 8 without extruding in my book.
If you really don't want your MMU and don't want to think about it anymore I can help make your problem go away for free... 😛
Some loss might be acceptable, but not that much 😛
Re: MMU finally coming
No it's worked pretty good for me. In that case I had to turn the sensor off for a yellow filament it didn't like and then forgot to turn it back on for a subsequent print. In my more recent jam issues where the sensor has been on it didn't stop it immediately, but it would catch it within an hour or so which is much better than running for 8 without extruding in my book.
I think one of the reasons it tends to fail (pure guess on my part) is that in a jam the filament will stutter as the gears try to force it and the motor skips steps; this still looks like motion to the sensor and it doesn't flag a jam... probably looks a lot like a retraction to the sensor so you'd have to err on the side of caution.
Some loss might be acceptable, but not that much 😛
Hehe... I did say that in jest, and I hope you either decide to keep it or have good luck finding a buyer at your desired price. But you'd be surprised what some people just give/throw away because they don't want to deal with it anymore. So I'd be lying if I didn't say a very small part of me was secretly hoping 😉
All in all, perhaps you could consider at least trying it out before selling it; then if it does turn out to be a headache you'll know for sure. I think the perceived time crunch is probably more perceived than real; according to the shipping table it's still quite a wait for new orders.... If you keep all the parts/docs together then(maybe) pre-assembled might actually net you a better price than kit form to someone that doesn't want to deal with assembly.
Re: MMU finally coming
The MMU2 can be a bit of a pain and takes time to learn, but the new things you can do with color and multi-materials makes it worth it.
I would keep it and try it out. Since the unit itself didn't change you can run the older MK3/MMU2 firmware to try it out without doing the extruder upgrade.
After a while, if you discover you like it, you can upgrade to the 3s extruder/firmware or if not, then sell it along with the unused extruder upgrade.
For .05 mm prints you can either slice with the MK3 printer setting with load to nozzle for single color or create you own .05 profiles in Slic3r and play with purge amounts until you get the purge amounts right for the color changes.
Re: MMU finally coming
Turns out that my OCD refusing to let a box full of parts sit unassembled was a helpful thing in this case as the IR sensor cable is missing from the box 🙄
Contrary to what the online support said, however, I can not "proceed with building the whole thing up until cable management which is near the end". I could advance a couple steps with minimal rework when the cable comes in, but it ultimately gets pinned between the X carriage and extruder body. So now I have a torn down printer and a desk (that I need for work tomorrow) covered in parts.
Hopefully their estimate on getting the replacement cable out will prove more accurate...
I know it's a minor thing and falls into "first world problems", but you'd think after all the delays that they'd be triple checking things before shipping them out...