Testing I3 MK3s Printer After Upgrading for MMU2s  

RE: Testing I3 MK3s Printer After Upgrading for MMU2s

Yes and I recommend it based on my experience.

Once you've built the extruder simply skip to the instructions (if you need them) to mount and reconnect the extruder. At that point you can power it on and flash the new S firmware and proceed to use it as the base printer.

This allows you to go ahead and dial in your Live Z and make sure that the IR sensor is behaving itself by running through some small test prints. 

While you are running test prints you can get back to assembling the MMU. Then when you have the printer all happy you can plug it in and start down the path of getting it to work.

I think Prusa's biggest mistake with the MMU is their build instructions that end up having you try to debug both the printer and MMU at the same time rather than focusing on each in turn.

RE: Testing I3 MK3s Printer After Upgrading for MMU2s

Gnat,

I made the update to the extruder and the only problems I seem to have now are:

1) The auto filament load doesn't work. The manual load does work.

2) At times the print stops and it wants me to unload the filament and reload it. Continues to work after completing that process.

I believe that it has to do with the spring tension as I changed it to get it to work as well as it does. Any suggestions as to the how to make any changes to get a  more consistent printing process. The test prints do come out good once finished.

I do agree with you about the manual it would be much better to fix one set of problems at a time.

Thank you for your help,

Steve

RE: Testing I3 MK3s Printer After Upgrading for MMU2s

Ah the wonderful IR sensor... Yeah you would have been miserable trying to diagnose this with the MMU installed 🙁 

I don't think it needs to be said, but don't proceed with the MMU until you have this sorted and can print with no false interruptions. Autoload and runout detection should work 100% of the time for you.

So if your bolt is tensioned correctly (roughly even with the surrounding housing), then the issue isn't the tensioner.

In the printed manual (heard it is getting added to the build instructions, but don't know if it is there yet) there are instructions for calibrating the IR sensor. Start there as that is the easiest.

If you are still having issues, then the issue may be the IR flag on the arm of the idler door or the door itself. To fix this you can try sanding down the "flag" at the tip of the arm so that it more reliably trips the sensor, but you may need to start with a fresh print of the door. There is one available that has an extended flag so you have more to work with ( https://www.thingiverse.com/thing:3572252 ). 

One thing I notice when I upgraded my extruder was that I could no longer push filament through to the nozzle like I used to be able to even when the tensioner bolt was barely biting into it's nut. In reprinting the door, not only was I able to shape the flag to play nice, but it is also a looser fit overall that allows me to manually move the filament with the tension properly adjusted.

RE: Testing I3 MK3s Printer After Upgrading for MMU2s

Gnat,

I did get the auto load to work after going through the IR sensor calibration. Although it does work it seems to take a lot of force on the filament to push it into the gear so that the sensor is activated. Once it is activated the process works fine.

My concern is that the amount of force would negate the operation of the MMU unit. The idler door assembly freely moves if the tension screw is removed. Just barely engaging the screw requires a lot of force to push the filament into the gears to activate the sensor. 

Have a nice day and thank you for the help,

Steve

RE: Testing I3 MK3s Printer After Upgrading for MMU2s

What is the easiest way to make the printer "forget" that it has an MMU2S attached? I am having a problem that I think has nothing to do with the MMU2S unit - can't load filament manually - but it's really awkward trying to do anything manually. Best idea I have is to unplug the MMU2S signal cables inside the main electronics box. (The other end is held in place by a not very accessible clip on the connector.)  I also have to disable the filament sensor, since it's in the wrong place for MK3S-only use.

RE: Testing I3 MK3s Printer After Upgrading for MMU2s

Posted by: sfshook22

Gnat,

I did get the auto load to work after going through the IR sensor calibration. Although it does work it seems to take a lot of force on the filament to push it into the gear so that the sensor is activated. Once it is activated the process works fine.

My concern is that the amount of force would negate the operation of the MMU unit. The idler door assembly freely moves if the tension screw is removed. Just barely engaging the screw requires a lot of force to push the filament into the gears to activate the sensor. 

Have a nice day and thank you for the help,

Steve

Yeah that sounds a lot like my case. I'd try printing a new door and see if that helps loosen things up. 

RE: Testing I3 MK3s Printer After Upgrading for MMU2s

Posted by: peridot

What is the easiest way to make the printer "forget" that it has an MMU2S attached? I am having a problem that I think has nothing to do with the MMU2S unit - can't load filament manually - but it's really awkward trying to do anything manually. Best idea I have is to unplug the MMU2S signal cables inside the main electronics box. (The other end is held in place by a not very accessible clip on the connector.)  I also have to disable the filament sensor, since it's in the wrong place for MK3S-only use.

You have to unplug it from the board. That's the only way as delivered. 

You don't have to disable the IR sensor. It will still work fine (if everything is setup and working properly) with the MMU tower in place. 

RE: Testing I3 MK3s Printer After Upgrading for MMU2s

Gnat,

I have printed the new door and will assemble it to see if it works any better. I followed your earlier suggestion.

Thank you again and have a great evening,

Stevve

RE: Testing I3 MK3s Printer After Upgrading for MMU2s

with the mmu style door installed autoload will be an issue. a normal mk3 senses the filament to trigger autoload at the top of the extruder housing. the MMU style door/sensor doesn't trigger till the filament moves the bondtech gears. 

on a non-mmu mk3 the sequence is;

• heat up hotend
• wait for filament
• start extruder motor
• after time delay slow down extruder and extrude purge
• stop and ask if filament is loaded and purged correctly

with a MMU installed the sequence is

• heat up hotend
• tell mmu to select required filament
• feed filament into selector
• detect filament in selector with Finda
• feed roughly the length of bowden tube toward extruder
• start extruder motor
• feed till filament engages bondtech as detected by IR sensor
• extruder feeds to prime 
• MMU idler disengages

on 1/2 and 1/2 machine with the mmu unplugged from the EINSY it will try and do the first but the sensor wont see filament till you force in into the bondtech

RE: Testing I3 MK3s Printer After Upgrading for MMU2s

Posted by: david.a66

with the mmu style door installed autoload will be an issue.

No it's not. You just have to poke it into the gears. At that point the motor kicks on and drives the filament for you. 

The trigger mechanism is indeed different, but after it is triggered it works exactly the same.