MMU 2.0 is not positioning the Idler correctly  

Re: MMU 2.0 is not positioning the Idler correctly

I am having an issue with the Idler not homing or going to the correct location. I am finding the Idler for Filament 1 rotated too far away from the home position and it is causing the idler to hit the plastic and not be located above the bondtec drivers.

Is it not homing? Or is it not moving to the right position once homed?

If it's not homing, check that the idler barrel can move freely to both stops, and that the screws holding the idler barrel to the stepper are tight. I saw a report from someone else that the screws had come loose.

If it homes properly when the MMU is initialized but sometimes gets confused and selects the wrong filament, this seems to be something that occasionally happens (I suspect a bug in the firmware). The solution is to reset both the MK3 and the MMU using the reset buttons next to their respective USB ports.

Re: MMU 2.0 is not positioning the Idler correctly

Yeah I just got done assembling and I'm having the EXACT same problem. It seems like the idler is moving opposite direction than it should be. ie: When it should be pressing on the bondtech to unload, it's actually rotated up (like in your video at the end) and so the bondtech just spins and spins but without any friction nothing moves.

When I manually put it in the right position and retract the filament out manually and then tell it to load it seems to be ok, and I can do the First layer Calibration (sometimes), but then when it goes to unload it again rotates as shown in your video and no unloading happens...

About ready to pull my hair out...

I seem to remember somebody posting that the wiring was wrong on one of his motors causing it to spin in the wrong direction, maybe that it?

Re: MMU 2.0 is not positioning the Idler correctly

I seem to remember somebody posting that the wiring was wrong on one of his motors causing it to spin in the wrong direction, maybe that it?

I'm also having the same issue. I think at this point it is either a bug in the firmware or a design flaw. Doubt we all have bad motors.

Re: MMU 2.0 is not positioning the Idler correctly

I have contacted Prusa Regarding this issue and it is how the MMU is intended to function. The idler is offset to assist in guiding the tube in. Once the motor detects presence of the element (I love the new stepper drivers) the motor rotates over the drive and pushes it forward.

This is a non issue. Please make sure the filament is straight and remove any bow that is present. Also make sure you have an angled cut in the filament. This fixed my issue with loading.

Thanks,
Adam

Re: MMU 2.0 is not positioning the Idler correctly

This is a non issue. Please make sure the filament is straight and remove any bow that is present. Also make sure you have an angled cut in the filament. This fixed my issue with loading.

Thanks,
Adam

A non issue? EVERY single error I have had has been because of the idler. Either not being tight enough causing the filament to not be gripped or too tight and it doesn't rotate to the next filament. When it doesn't rotate properly you have to remove the screws and manually position the idler since it isnt smart enough to reset itself. Half the time I have to babysit it because it doesnt work properly. When I finally have it working correctly for 100 color changes it randomly decides to not rotate and then I have to remove the screws, rotate it, and then start over from scratch.

Glad you dont think it is an issue, but you aren't the center of the universe and other people DO have a problem with it. To say it is a non issue is arrogance. Why dont you go tell all the people on the general forums with problems that they are doing it wrong? That should go over well.

Re: MMU 2.0 is not positioning the Idler correctly

This is a non issue. Please make sure the filament is straight and remove any bow that is present. Also make sure you have an angled cut in the filament. This fixed my issue with loading.

Thanks,
Adam

A non issue? EVERY single error I have had has been because of the idler. Either not being tight enough causing the filament to not be gripped or too tight and it doesn't rotate to the next filament. When it doesn't rotate properly you have to remove the screws and manually position the idler since it isnt smart enough to reset itself. Half the time I have to babysit it because it doesnt work properly. When I finally have it working correctly for 100 color changes it randomly decides to not rotate and then I have to remove the screws, rotate it, and then start over from scratch.

Glad you dont think it is an issue, but you aren't the center of the universe and other people DO have a problem with it. To say it is a non issue is arrogance. Why dont you go tell all the people on the general forums with problems that they are doing it wrong? That should go over well.

I don't think he is saying "there are never any idler issues". I believe what he is saying is:

"When you first turn on the printer with no filament loaded, the idler turns further (with the bearing not engaged with the gear) to guide the filament into the selector. Once the filament is inserted and the finda detects it, the idler rotates back and engages the gear".

Basically, he's saying that what was shown in the video is expected functionality.

If you have other problems, or the idler isn't rotating back after the filament is inserted, show a video of that or describe it and we can try to help diagnose.

Also, you seem to have somewhat overreacted. Adam was (calmly, reasonably) trying to assist you by pointing out that the behavior you thought was broken was not, and explaining why the idler behaved that way. By reacting the way you did you make it less likely others will be motivated to help you diagnose the other idler related issues you have.

Re: MMU 2.0 is not positioning the Idler correctly

This is a non issue. Please make sure the filament is straight and remove any bow that is present. Also make sure you have an angled cut in the filament. This fixed my issue with loading.

Thanks,
Adam

A non issue? EVERY single error I have had has been because of the idler. Either not being tight enough causing the filament to not be gripped or too tight and it doesn't rotate to the next filament. When it doesn't rotate properly you have to remove the screws and manually position the idler since it isnt smart enough to reset itself. Half the time I have to babysit it because it doesnt work properly. When I finally have it working correctly for 100 color changes it randomly decides to not rotate and then I have to remove the screws, rotate it, and then start over from scratch.

Glad you dont think it is an issue, but you aren't the center of the universe and other people DO have a problem with it. To say it is a non issue is arrogance. Why dont you go tell all the people on the general forums with problems that they are doing it wrong? That should go over well.

I don't think he is saying "there are never any idler issues". I believe what he is saying is:

"When you first turn on the printer with no filament loaded, the idler turns further (with the bearing not engaged with the gear) to guide the filament into the selector. Once the filament is inserted and the finda detects it, the idler rotates back and engages the gear".

Basically, he's saying that what was shown in the video is expected functionality.

If you have other problems, or the idler isn't rotating back after the filament is inserted, show a video of that or describe it and we can try to help diagnose.

Also, you seem to have somewhat overreacted. Adam was (calmly, reasonably) trying to assist you by pointing out that the behavior you thought was broken was not, and explaining why the idler behaved that way. By reacting the way you did you make it less likely others will be motivated to help you diagnose the other idler related issues you have.

Thank you for that post. I couldn't have said it any better myself. I initially over reacted in my excitement trying to get this corrected on my end. I did not want to lead to any negative feedback for a product I misunderstood.

Thanks,

Adam

Re: MMU 2.0 is not positioning the Idler correctly

Also, you seem to have somewhat overreacted.

Unfortunately, that is perhaps somewhat understandable given the current situation.

I believe the PR guys are working very hard to resolve all the problems and hopefully we should have some news by the middle of next week.

For those experiencing problems, there really is no quick fix. These problems have to be repeatable in-house, diagnosed and then fixed; this is not a quick process.

Peter

Re: MMU 2.0 is not positioning the Idler correctly

For those experiencing problems, there really is no quick fix. These problems have to be repeatable in-house, diagnosed and then fixed; this is not a quick process.

Not a quick process?

Based on reading the forums here, I thought it was a stone-cold fact that all the Prusa developers are idiots, the MMU2 design is fundamentally flawed and never should have replaced MMU1, that all Prusa products are crap, and nobody anywhere has managed to get the MMU2 to work. All Prusa needs to do is hire some guy who put together a 30-second demo video and everything will be fixed in a few days.

</sarcasm>

I think it's easy to forget just how hard it is to go from a few dozen machines that work in a beta environment with experienced users, to mass producing thousands of machines which will be used with all kinds of crazy materials and by relatively novice users who expect their MMU to be as simple as their MK3 despite exponentially more variables and print complexity.

So thanks for reminding us that even fixing simple problems is complicated when ramping mass production, and that some users' expectations may be a little unrealistic.

Re: MMU 2.0 is not positioning the Idler correctly

Also, you seem to have somewhat overreacted. Adam was (calmly, reasonably) trying to assist you by pointing out that the behavior you thought was broken was not, and explaining why the idler behaved that way.

I did overreact. He said it was a "non issue", which I took offense to because I thought he was belittling problems other people are having. I didn't realize he was the topic creator and was responding to his own situation. I wasn't asking for help, just pointing out the facts of my situation. My idler does not always rotate correctly due to the extremely narrow tension window. Sometimes it fails. Too tight and it doesn't rotate, too loose and it doesn't allow the parts to grip the filament. I never claimed something was broken that wasn't. In fact, I really like my MMU2, but the idler is definitely the weakest link IMHO and the design should have been changed.

By reacting the way you did you make it less likely others will be motivated to help you diagnose the other idler related issues you have.

I think you are confusing me for someone else. I don't have any other idler related issues.

Re: MMU 2.0 is not positioning the Idler correctly

Also, you seem to have somewhat overreacted. Adam was (calmly, reasonably) trying to assist you by pointing out that the behavior you thought was broken was not, and explaining why the idler behaved that way.

I did overreact. He said it was a "non issue", which I took offense to because I thought he was belittling problems other people are having. I didn't realize he was the topic creator and was responding to his own situation. I wasn't asking for help, just pointing out the facts of my situation. My idler does not always rotate correctly due to the extremely narrow tension window. Sometimes it fails. Too tight and it doesn't rotate, too loose and it doesn't allow the parts to grip the filament. I never claimed something was broken that wasn't. In fact, I really like my MMU2, but the idler is definitely the weakest link IMHO and the design should have been changed.

By reacting the way you did you make it less likely others will be motivated to help you diagnose the other idler related issues you have.

I think you are confusing me for someone else. I don't have any other idler related issues.

Sorry about that, I misunderstood what you meant when you said "EVERY single error I have had has been because of the idler".

BTW, I just checked with my MMU2, power cycling it several times. At boot it does exactly the same thing as was shown in the video: the selector slides back and forth several times, ends up at filament #1, and the idler kicks the bearing all the way forward. If I then hit the middle button to load filament into #1, it rotates back correctly (at least for me) to a position over the gear and correctly grabs the filament. Since my MMU2 is working quite well (knock on wood), I suspect this behavior is planned, or at the least not significantly detrimental to correct operation.

I have not updated to the latest firmware, and now I'm hesitant to (in case something in the latest firmware is causing idler issues)

RE: MMU 2.0 is not positioning the Idler correctly

This one saved me! The mmu2s was systematically off by one with the filament selection. I'd been trying to see what was wrong with the mmu, doing factory reset, etc. At the end, it was a matter of reseting *both* the mmu2s and the 3d-printer. Thank you!!

RE: MMU 2.0 is not positioning the Idler correctly

I had a very similar problem - the idler wheels were positioning over the gap between the driver and the guide hole so there wasn't enough pressure to load or unload without help.  In my case I eventually figured out that the screws that connect to the idler motor had worked loose - tight enough that the idler would look like it was working, but loose enough to cause problems.