MMU3 and E3D Revo Six  

RE: MMU3 and E3D Revo Six

Very nice detective work @antimix. On the topic of the temperature mismatch though, this has already been identified from the beginning by CNC Kitchen and others doing similar testing, and it appears to come down to the thermistor location in relation to the ceramic heater and nozzle. The takeaway has always been that the Revo needs 5-10c hotter target temperatures to match the standard V6 setup.

With that said though, #3 is the HUGE takeaway for me. It makes sense in hindsight since we have to use a shorter PTFE run for the V6 revo hotend, but I didn't realize that small change would results in such a difference for tip formation.

RE: MMU3 and E3D Revo Six

@antimix's post provides a lot of good information.

I've been using an MMU2S with a Revo 6 since the Revo was first released and have had almost no problems compared to a lot of folks, but I have always had very fine stringing.  Almost like cobwebs.  I'm in the process of replacing the Einsy (xFlash failure) and upgrading the MMU to MMU3.   I'll definitely try changing the filament parking position once I'm up and running again.

RE: MMU3 and E3D Revo Six

@antimix: Thanks a lot for your investigations. When I read the drawind correctly, the difference between the old and new tube center is 5mm:

- old center: 25 mm from z=0 (printing plane)

- new center: 20 mm + 10 mm = 30 mm from z=0

As new setting for the filament parking position you have choosen 82 mm. But the standard setting (in Prusa Slicer 2.7.1) is 85 mm. So the difference is "only" 3mm. Is there any reason why you have not choosen 80 mm?

BR

Oliver

RE: MMU3 and E3D Revo Six

GUESS WHAT.....

I tried a print test with MMU3 and multi-material (PETG & PLA). I loaded PLA in MMU3 material 2, and PETG in material 5.

When I started the print I almost immediately noticed that no filament was coming out from the nozzle to the initial purge line. Then I noticed also that the nozzle temp was 230°, like PrusaSlicer confused that the starting nozzle (2-PLA) was PETG.

Result: completely blocked filament in the Revo Nozzle. No way to remove the filament, even when it was hot at 200°.

I had to cooldown the nozzle, cut the filament, and unscrew and remove the nozzle.

I suspect it is completely melted all around the tube, even in the supposed cooled part. I am not sure if I will be able to remove it using hot air and save the brass nozzle. 😪 

I think this situation could not happen with the original PRUSA stock E3D nozzle. This means that REVO require much more attention on the filament temperature settings.

RE: MMU3 and E3D Revo Six

Good, hot gun at 170° all around the nozzle and in 30 seconds the PLA filament exited intact.
However, when I was printing and the filament it was stuck, there was no other way to exit from the RETRY error  process on the LCD than reset the printer 😣 

Strangely after the reset & reboot, I noticed the Nozzle temp was around 80°.... 🤔  to low in so short time, as if during the RETRY error the nozzle process, the nozzle heating was turned off, creating a new issue that do not facilitate the filament extraction....

RE: MMU3 and E3D Revo Six

I had never issue with MMU3 and my MK3S+. But I remember, i'm not using the original head but this one https://www.printables.com/fr/model/66215-tzb-mk3smk25smmu2s-extruder-mmu2s-no-tower-v3 (I don't use bl-touch). Maybe that help.

RE: MMU3 and E3D Revo Six

Thanks for the info @Antimix, after changing the park to 82mm and a small IR sensor adjustment my MMU3 and i3MK3S+ with Revo Six Prusa Edition seems to be working well.

I just need to enclose the top mounted spools with some desiccant holders before it gets humid here.

RE: MMU3 and E3D Revo Six

I built several dry boxes, all around. You can do the same, and put them on the top of the enclosure or on the back.

Those are an evolution of the Marsgizmo Drybox Filament Bunker.

I originally built the Marsgizmo version, but then I noticed that they were too sensitive to the size of the boxes, that are difficult to find and are sold in non standard sizes, always different from batch to batch.  I was unhappy because it had too much friction.
So I designed my version based on the exact size of the boxes, and I developed a new version of the internal mechanism, this time with a rolling bar in the middle of the spool. ZERO friction, and I was very happy. I built 6 of them, but then.... 😯 
After some usage I discovered that the friction was so small, that just the small spring force of the filament was enough of roll the spool and unspool internally the filament mixing all the filaments turns 🤬  It worked like a charm on the FLSUN V400 that uses lots of filament, but the spool were always messed up. So I decided to change them.

I redesigned the mechanism, adding some friction, using the original PRUSA filament holder logic,  but allowing small and big spool to fit into my box. I put also several filament exits, because on my FLSUN V400 it is more convenient to use a different exit than the one I use on MK4 or MK3S+/MMU3.

RE: MMU3 and E3D Revo Six

Nice boxes. Can you tell the exact type name or even the EAN? Those are exactly what I am looking for. Do Prusa 1kg spools (d=200mm;w=70mm) fit into them?

Until now, I haven't found suitable boxes in shops here in Germany and would prefer to buy them locally or from well known shops in the EU.

Thank you.

RE:

Look like Wildone Storage Containers Set - that's USA version. There is almost similar container in Europe called GoMaihe. I was looking for sealed cereal box for my filaments and I found this https://www.printables.com/model/483525-4l-filament-dry-box-system-quickeasy The designer used GoMaihe (Europe version) that led me to find correct container size. 

It will fit Prusa spools (not 2kg spool). 

RE: MMU3 and E3D Revo Six

Thank you. The problem is that those GoMaihe boxes also have recessed gripping sides. Even though some sites mention the outer width at the bottom, the inner width is never mentioned. For cereal boxes that isn't an issue. The author of the printables mentioned: "you may have to expand it with a heat gun, they are very narrow in one place. without heatgun work only small rolls are working". And I try to avoid that.

It would be ideal to get a sealed "plain box" with neither recessed sides nor opening flap.

RE: MMU3 and E3D Revo Six

I took something similar. Unfortunately just after the purchase they were out of stock, and similar boxes sold on Amazon use the same picture, but the real measure are different. They are (based on the seller):

• Scaled, so the image seems the same, the size is little smaller (to save plastic costs) and the spool barely fit.
• No exact measure are given in any description. Only a raw measure not specifying inside/outside, and plastic thickness.
• All of them are not rectangular but trapezoidal, and they give always the width of the larger trapezoidal side. As result, surprise surprise, there is plain of space on the larger side to fit the spool, but the spool barely fit or does not fit at all, on the smaller side of the box. As results the box are not usable.
• The box seems fine, but the two vertical "handler" are too deep inside, and create friction with the spool.
• It is never given a real EAN/UPC code of the product, they are all dummy seller inventory codes.

As result I was not able to get more than my 6 units, and after I shipped back 2 orders I got 1 sample from Aliexpress that I could not return, I temporary stopped to randomly order. 😒 

RE: MMU3 and E3D Revo Six

Posted by: @blauzahn

Thank you. The problem is that those GoMaihe boxes also have recessed gripping sides. Even though some sites mention the outer width at the bottom, the inner width is never mentioned. For cereal boxes that isn't an issue. The author of the printables mentioned: "you may have to expand it with a heat gun, they are very narrow in one place. without heatgun work only small rolls are working". And I try to avoid that.

It would be ideal to get a sealed "plain box" with neither recessed sides nor opening flap.

I just browsed Amazon.de and I see what you mean about grip side. I tried to find something similar like US side and found nothing. 😔 

I would avoid Rubbermaid cereal box because it's not 100% airtight like Wildone/GoMaihe. 

IKEA have airtight container that can fit two spools or more, it's called 365+ food container ( https://www.printables.com/model/55896-desiccant-container-for-ikea-365-106l-box). That's the best I can think/suggest. 

RE: MMU3 and E3D Revo Six

Thank you for the info.

RE: MMU3 and E3D Revo Six

I came across this topic as I was looking at reducing the stringing when printing with a Revo nozzle and wanted to share my settings and findings as it may help others.

I am running an MK3S+ with MK3.5 upgrade(highly recommended) and E3D Revo hotend/nozzle.  I initially modeled my settings off the MK4 MMU3 settings as I wanted to use the stamping feature that was mentioned in Prusa's MMU3 Dev Diary blog.

Here are some of the things I have found:

• Unloading speeds and Ramming Settings are very important and required a lot of adjusting to get right.
• Temperature settings need to be lowered, but not as much as default settings.  Input shaper works better when temperatures are higher which contradicts the idea of lower temperatures needed for MMU printing.
• Stamping Distance should be same as in your printer settings.
• Ramming more filament creates gaps in the wipe tower if not compensated.  Changing the 'extra load distance' within printer settings helps with this.  An added benefit is reducing the purge volumes as this is now done at the point of ramming.
• Ramming load width % and spacing % needs to be increased when ramming more filament.  If not increased you get blobs on the wipe tower which can cause nozzle to hit which can create layer shifting and other issues.

Below are my current settings that seem to provide the cleanest looking tips with minimal stringing.  These are for PLA and I have not tested PETG.

RE: MMU3 and E3D Revo Six

I have also a Prusa MK3.5 and MMU3. Every time when I have a big colour print after one cm it starts to print in the free air.

It looks as the revo is failing. Jammed or wat ever. Would the settings above fix this too?

RE: MMU3 and E3D Revo Six

Not sure.  I would open up the idler door on the extruder and make sure there isn't a lot filament stuck in there.  That was one of my issues which was caused by excess stringing when the mmu3 changed colors.

If you aren't getting a clicking sound like a normal jam, then you may need to adjust your filament sensor.  If filament sensor is set too sensitive it may think filament has reached the extruder when it actually hasnt.  Also, I find having the idler door screw too tight can also create issues.

Unfortunately it's not always easy to pinpoint an issue.  I hope you can find the issue.

RE: MMU3 and E3D Revo Six

Do you hear the grinding noise of the gears ? Does it chew the filament? Or do you think its blocking? 

Don't change ramming settings .

RE: MMU3 and E3D Revo Six

I have just installed the MK3.5 with REVO on my MK3S+/MMU3.

First I installed the 60W REVO heater for high speed, just to have to dismount it again 🤬 and reinstall the old 40W, due to the fact the FW 6.0.0 for the Buddy board do not support the 60W version.

I did not had the time to work on it yet, since I am working on finishing a new set of filament Dry Boxes on the MK4. I was not able to source the original cereal boxes any more, so I had to find a new one that could be fit a spool inside, but then I had to redesign on the CAD the internal parts, since the boxes had a different size.

As soon as I finish, I will have to review all the MK3.5 settings and see how it performs with the new FW.

Regards

RE: MMU3 and E3D Revo Six

@chrisg Please check how tight is the REVO.

During my Mk3.5 update, I had to dismount the REVO, and when I reassembled it I was unsure if I had to screw it correctly.

I realized that I was too soft with the touch, and the nozzle silicon cover was just shifting on the copper and I had not really screwed it to the end. This could have caused change on the nozzle position and potential air print.

Remember that after any nozzle change you have to retune the fist layer height.

Regards

Posted by: @chrisg

I have also a Prusa MK3.5 and MMU3. Every time when I have a big colour print after one cm it starts to print in the free air.

It looks as the revo is failing. Jammed or wat ever. Would the settings above fix this too?