Support for additional nozzle sizes on MK4 + MMU3  

RE: Support for additional nozzle sizes on MK4 + MMU3

The nozzle size settings can be changed in PrusaSlicer and the MK4, but I haven't tried it - yet. I don't know why the MMU3 would need a 0.4 nozzle, so I assume the 0.6 would work.

RE: Support for additional nozzle sizes on MK4 + MMU3

This is from the most current PrusaSlicer - no other nozzle sizes than 0.4 for MMU3 currently available. Hope this changes in future versions.

Has anyone tested printing with 0.25 nozzles on MMU3 + MK4 with custom profiles already?

RE: Support for additional nozzle sizes on MK4 + MMU3

I came hear looking for an answer to that same question as well as one other...

How is compatibility with the Nextruder to V6 adapter and V6 nozzles as opposed to original Nextruder nozzles with full continuity from the heat break through to the nozzle?

RE: Support for additional nozzle sizes on MK4 + MMU3

I was able to get a print using a v6 nozzle by using all the v6 profiles in PrusaSlicer and telling the printer to ignore the nozzle diameter. That being said, I did install a v4 nozzle and the whole MMU3/MK4 print because better. So, will it work with V6? Yes, and maybe they're working on a profile for it, but it's not quite as nice.

RE: Support for additional nozzle sizes on MK4 + MMU3

I agree with the OP. Where are the missing nozzle size options in the Slicer? Is there are problem (beside all the other issues) with the MK4/MMU3 combo. Filament change / purge tower issues?? What needs to be adjusted?

RE: Support for additional nozzle sizes on MK4 + MMU3

My guess is because they have focused entirely on an 0.4 mm nozzle. This is the "standard" nozzle size, so it's what you would tune for first. They had enough trouble making sure the tips were well formed with 0.4 mm nozzle to worry about other sizes.

As mentioned, it's quite possible to change the nozzle size yourself. If I was doing this (and I may try, as I want to do minis in multi-color), I'd first compare profiles between 0.25 nozzle (or other size), and the 0.4 mm non-MMU profile. List out all the differences between the two profiles. Then go to the 0.4 mm MMU profile, duplicate it, rename as 0.25 mm and change all the items in the list created previously to match that of the 0.25 mm nozzle.

The only potential issue I see right now is the new ramming procedure the MK4 does on unload for tip shaping may be too fast/not suitable for a 0.25 mm nozzle. And for a bigger nozzle it may need to be faster yet. You could tune this too, just that if you go into Filament Settings > Advanced > Toolchange parameters with single extruder MM printers > Ramming parameters to adjust, you get the following warning:

Ramming denotes the rapid extrusion just before a tool change in a single-extruder MM printer. Its purpose is to properly shape the end of the unloaded filament so it does not prevent insertion of the new filament and can itself be reinserted later. This phase in important and different materials can require different extrusion speeds to get the good shape. For this reason, the extrusion rates during ramming are adjustable.

This is an expert-level setting, incorrect adjustment will likely lead to jams, extruder wheel grinding into filament etc.

In other words, yeah this is totally possible. Just gotta know what you're doing and be willing and able to fix jams and other issues caused while getting the tuning correct.

RE: Support for additional nozzle sizes on MK4 + MMU3

Good suggestion -- I made a preliminary profile for a 0.25mm nozzle on the MMU3 config and gave it a quick test. Retracted filament tips looked pretty good - very close to the shape for the 0.4mm case. Your observation that the ramming parameters probably need adjusting down for the smaller cross-section nozzle but I need to know more about what I am looking at when displaying the settings. Also, it appears that the ramming params are set in the filament profile(s) selected by the printer setting chosen. The MK3S/MMU3 filament selections are dependent on nozzle size - This will probably be the case for the MK4/MMU3 setup as well. It is worth noting that the filament profiles for the MK4 and MK4IS for 0.26 - 0.5mm nozzles are the same and the 0.6mm and 0.8mm nozzle sizes are slightly different. 

Purge volumes may also need to be adjusted - some experimentation required going forward as well as looking into ramming params adjustments.

RE: Support for additional nozzle sizes on MK4 + MMU3

I'm also interested in different nozzle sizes. Would printing in Single Material mode allow for printing with a .6 or .8 nozzle? I haven't fully assembled mine yet.

RE: Support for additional nozzle sizes on MK4 + MMU3

Posted by: @ram64

I'm also interested in different nozzle sizes. Would printing in Single Material mode allow for printing with a .6 or .8 nozzle? I haven't fully assembled mine yet.

I haven't tried it yet, but I think so. From what I've read, when printing a single material print, the only difference when actually printing is the printer asks you which of the five filaments you want to use for the print. So you slice with the non-MMU printer profile and then load it up, and the only thing the MMU does is select your desired filament at the start.

RE: Support for additional nozzle sizes on MK4 + MMU3

Tried it, works fine. I had a new thermistor to test on a 0.25 mm nozzle assembly to replace a presumed bad thermistor. Sliced a file with the non-MMU 0.25 mm profile, went to print and it asked which filament to use. I selected 2, which was the color I wanted to use. It loaded the filament to the Nextruder and began printing as normal.

So yes, you can print in single-material mode with any size nozzle there's a profile for (or one you create). The only thing lack of profiles besides 0.4 mm for the MMU affects is MMU prints.

RE: Support for additional nozzle sizes on MK4 + MMU3

How you realized it? I tried today with 0.25mm, newest FW.

Indeed, adjusting in slicer works like a charm, BUT once I changed to 0.25mm Nozzle in the Hardwaresettings of the Printer, then I got hit by the full portion of stupidity.

the reason is, after you changed the nozzle size, the Fsensor in the MMU is now used as the Extruder FSensor, which means you always get the error that FSensor too early. 
but the curiosity is, that all the rest, selector, pulley etc works as expected. You can select every filament…

And what it makes more bad is, that in the hardwaresettings, nextruder is, how the Fsensor should be handled, and this setting remains to MMU. If you change, than the MMU stops working

RE: Support for additional nozzle sizes on MK4 + MMU3

I need to correct my last posting...

After my MK4 showed some really strange behavior (tried to move selector while filament was loaded and sensor showed that filament is loaded) I decided to make a factory reset.

After that I could set 0.25mm in the Hardware settings and the Fsensor MMU behavior was as expected.

I also observed at the first try, that in the filament setting I only had the options to load filament to nozzle and unload...

Maybe that information helps other in the future if they also observing that behavior.

Greets Thorsten

RE: Support for additional nozzle sizes on MK4 + MMU3

Still waiting for this to get updated. I would like MK4S to use 0.25 nozzle. I see that MMU and MK3 has config for other nozzle sizes, but not MK4 or MK4s. How long until these are sorted out?

Anyone else with ideas...?

RE:

I added the other MMU nozzle profiles with the GitHub workaround, specifically because I wanted to use the 0.25mm nozzle for some projects.

The tips looked fine at first glance but it became clear that there was some melted filament left in the melt zone and not retracted after the ramming step. I needed essentially zero purge with the magical ramming settings on MK4+MMU3+0.4mm nozzle, which has worked flawlessly for me thus far (knock on wood). After switching to 0.25mm nozzle it was like going back to the MK3+MMU2 with the normal large purge volumes.

It would be amazing if Prusa could come out with the profiles for the different nozzle sizes. But it's become clear to me that these settings are absolutely not plug-and-play, and Prusa probably have bigger fish to fry. I have some time to toy with the ramming settings this weekend, so we'll see if I can luck onto a combination that works with the 0.25mm nozzle.

My guess right now is that the lower volumetric flow of the smaller nozzle does not allow the ramming procedure to clear the melt zone as much as the slicer expects. But of course when the ramming procedure takes longer, more filament will liquify in the melt zone and need to be cleared. I'm not sure if the volumetric flow rate of the 0.25mm nozzle can overcome the flow rate of liquifying filament.

RE: Support for additional nozzle sizes on MK4 + MMU3

If different nozzles are sold, at least we should be able to use them. Or else it hat to be very clear stated that the printer only works with one specific nozzle.

RE: Support for additional nozzle sizes on MK4 + MMU3

I would very much like to see MK4S + MMU3 profiles for 0.25 mm nozzles as well.  My plan was specifically to be able to use this printer to print multi color parts with fine details such as text.  The thought was it would be much quicker to configure the MK4S to use the MMU3 and switch the one nozzle to a 0.25 mm, vs having to switch all 5 nozzles on my XL to 0.25 mm and recalibrate it all to do the same prints.  That is not even taking into consideration the cost of all the 5 nozzles I'd need for the XL.

I certainly hope Prusa is working on getting a 0.25 mm nozzle profile for the MK4S + MMU3.  Also, if anyone does do this as a custom profile themselves and has good results, it would be great if you guys could share that profile here.

Regards,

Bryan