MK4s kit with MMU3 built at once  

RE: MK4s kit with MMU3 built at once

Posted by: @marb

Hi all, I started building MK4s kit which I bought with MMU3. How much time can I save by building it straight with MMU? Are there instructions to do it? MMU instructions count with printer being assembled…

Or should I just build mk4s first and than move to MMU?

I am not afraid of more complicated troubleshooting. But vision of spending some hours on extruder only to disassemble it day later seems wasteful. 

i built my 3.9 first, then added the mmu3, it wasn't a lot or extra work. 

Joan

RE: MK4s kit with MMU3 built at once

I did build both at once (for assembling the Nextruder I was reading both the MK4S and MMU3 assembly instructions simultaneously) and it worked perfect.
I believe people who buy kits are technically educated and/or have the typical handyman's skills so I believe Prusa should trust us to build both at once.
Anyway... for those who can read two different manuals at once (MMU3 and MK4S), go for it, it's simple enough.

RE: MK4s kit with MMU3 built at once

How did you get on? The last I read was that the MMU3 didn't work too well with the new HF Nozzle? Have you revert back to the standard nozzle or is the HF working Ok for you?? 

I'd like to give MMU3 a try, but not if I have to change nozzles just to use it......

Posted by: @mike1d

I did build both at once (for assembling the Nextruder I was reading both the MK4S and MMU3 assembly instructions simultaneously) and it worked perfect.
I believe people who buy kits are technically educated and/or have the typical handyman's skills so I believe Prusa should trust us to build both at once.
Anyway... for those who can read two different manuals at once (MMU3 and MK4S), go for it, it's simple enough.

RE:

I tried both, HF and non-HF. Both work perfect and smooth. No single glitch with MK4S or MMU3 in this combination.
In fact, with this whole MK4S and MMU3 I was really surprised everything works absolutely perfect out of the box with no tweaking. Thought it might be different considering a self-assembled device,

The nozzle change is fast with https://www.printables.com/model/980297-mk4s-nozzle-replacement-tool
So when I'm really printing multi material (I only bought it for support interfaces because I mainly print functional parts so I can have printed item and support for example in PETG and support interface in PLA) I use the standard nozzle. Only for bigger amounts of single material I use the HF nozzle.

When you do multi material prints the HF nozzle's disadvantage is the high amount of purge volume required with each material change. In the Prusa slicer's printer profile you can see the volume (waste) with the HF nozzle is 3x higher (purging volume 80 vs 240 mm³).

RE: MK4s kit with MMU3 built at once

Got a question Mike.  Have you inspected the filament tip quality following the filament being withdrawn from the high flow nozzle when using a MMU3 profile?

I'm wondering if they were able to shape it well enough to prevent feeding problems during multi color printing. Being a long term MMU user this concerns me. 

I ordered the 4S upgrade anyway, but still I'm wondering what the tips will look like. 

RE: MK4s kit with MMU3 built at once

@Lynn,
Before I changed the HF nozzle to the regular one I did several prints with it and the MMU3. All were successful, no issues at all so I actually didn't have a need to check the tip.
Only when I changed the nozzle to the standard one I had a look at both the PETG and PLA filament tip.
PLA tip was mainly round, kind of like a half sphere shape, PETG tip was a bit sharper with a probably 2mm hair sized string at the front.
I guess both would be ideal shapes for the MMU3.
Still I changed to the standard nozzle because of the reduction in filament waste.

RE: MK4s kit with MMU3 built at once

Thanks Mike, 

I have experience with the CNT nozzle and sometimes the tips comeback a little funky. I guess we'll see. For now I think the HF nozzle will only be used with single filament projects.  Just sounds smarter.

RE: MK4s kit with MMU3 built at once

I started with an MK4+MMU3 and upgraded with the 4S kit. I kept the idler arm from the MMU3 and using the high flow nozzle/hot head that came with the 4S kit. The 14 minute Benchy gcode I downloaded from Printables ran fast. But when I re-slice my older items they don't show any speed benefits. I have the firmware and software updated, the MK4S with MMU selected in Slicer, but I don't notice any increase in speed. What am I missing? 

RE: MK4s kit with MMU3 built at once

I don't have the 4s upgrade installed yet, but since HF nozzles only increase the available plastic per unit time it only makes sustained higher speeds possible.  That means you can possibly print an object faster because the nozzle to melt the plastic at a higher rate, but you may to have to manually increase the print speed to get it done. 

I suspect that increased speeds are part of the HF profiles, but I don't yet have them installed to look at them for you. Also, some of the HF settings are not available in PS 2.8.0.   PS 2.8.1-RC1 is out there and it does have more settings to support the HF nozzle.

RE: MK4s kit with MMU3 built at once

@lisa-zark,
With the HF nozzle you will mainly see a speed improvement where you print with higher speeds which means fine structures where the print head and print bed spend a lot time accelerating and decelerating there won't be any significant difference.
For example the standard benchy. Sliced with 0,2 mm "SPEED", PLA and HF nozzle it will be 36 min, normal nozzle 37 min.
A significant difference between standard and HF nozzle I see only for prints with simple structure and high infill. Try adding a shape 200x200x200 with 100 % rectilinear infill and you will see a difference.
At least if you stick to the profiles that Pruse delivered.

@lynn,
I don't believe these settings you mentioned are related to speed in any way.
The setting in the slicer (HF/non-HF and standard/hardened) are done in the printer and filament profiles to warn a user when you try for example printing a carbon fiber filament but you don't have a hardened nozzle installed.
But for this to be working you'll also need the latest firmware on your printer where you can set this information but this firmware is currently still in alpha state. A bit too early for me to try.
https://github.com/prusa3d/Prusa-Firmware-Buddy/releases/tag/v6.2.0-alpha1

RE:

@mike1d.

You are correct about the mentioned HF settings being for user warning messages. and that volumetric flowrate adjustments are not necessary if you are using the HF profiles, which was not a given.  My underdefined point was that the maximum volumetric flowrate will cause the slicer to limit actual print head speed regardless of the speed settings you select if the selected print head can't extrude the plastic fast enough support the speed setting. In fact, before IS, some of us would leave our print speed settings high (like 200mm/s) and control extrusion by allowing the slicer to cap speed based on maximum extrusion volume. 

If the HF profiles are installed with IS none of this is necessary because the Prusa team does the groundwork for us.