Manual filament swap when using MMU2
Hello, I have a model which uses 8 colors total (only 5 at most on a layer). This requires that 5 colors are loaded, and at some point in the print 3 of them are changed out for other colors. In PrusaSlicer, I did this by navigating to the layer I want to swap at, clicking the + sign in the layer slider, and adding a color change. This seems to work well, PrusaSlicer shows a sliced model with 8 different colors, and acknowledges that there are filament swaps at some point (eg. Blue tool 2 used until 38mm, green tool 2 used after 38.2mm).
In practice, here is what really happened. For the first filament change, printer paused and hot end cooled down in a safe location. Filament was not unloaded. I had to manually navigate the printer menu reheat the hot end, then pull the filament out by hand (because there was no unload option in the menu), then load the new filament and continue print. For the second tool change planned in PrusaSlicer, the printer completely ignored it and continued printing, thus producing part of my model with the wrong color. After waking up and seeing this, I changed the filaments on the fly but it was too late. Some time later, the MMU2 encountered another error. When resolved by clicking the button as directed on the LCD, the hot end proceeded to drive over the model, lower itself into it (causing a crash) and resume the error state again. This was an endless loop and caused the total loss of print job, as every effort to clear the error caused the printer to crash into the model. Interestingly, the height it was trying to drive down to was the last height where that filament that needed changing was used (or possibly the height where the filament swap was programmed and skipped over previously, they were about the same).
So what is the correct way to do a manual filament swap when using the MMU2? I expect a filament swap to move the print head to a safe location, unload the previous filament at its working temperature, beep at me saying its ready, and then allow me to load the new filament, extrude some material and ask me to confirm that the color change was successful, at which point the print should proceed. This is very far from what happens in practice.
RE: Manual filament swap when using MMU2
The kind of filament change you are describing in the end is not available with the MMU2 installed only without.
It is possible to change the filament in a different slot than the one in use at any given time during print. The worst that can happen is a load fail because you did not insert the filament far enough (it‘s what usually happens to me, to be honest), but that‘s easy to handle if you are doing the change near the time the filament is used. You can use the pause printing option in slicer to pause the print for that, but you do not have to. And of course you do not see the correct colors in slicer…
I used that technique a few times for models with more than 5 colours, it works…
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Find out why this is pinned in the general section!
Changing a filament that is not currently printing is the way to go but it can be an administrative nightmare keeping track of what goes where.
When the colours get this complicated printing plain and painting is often the better option.
Cheerio,
RE: Manual filament swap when using MMU2
Thanks for the input. The help article on this topic is confusing, and after reading again just now I still think that they might be saying it should be possible... but maybe I am misunderstanding. Option 3 is the one I'm referring to here, they describe combining tool changes and color changes to make an 8 colored model. Anyway I will go with the pause and manual swap like you recommend. Thanks