MK3S+ kit and MM2S upgrade order of installation?  

RE: MK3S+ kit and MM2S upgrade order of installation?

If this is your first printer, I would recommend you to use the MK3S+ for some months before you do the MMU.

Make it work, get used to it and learn how to calibrate materials before you introduce new error sources.

RE:

Having just done the MMU2S upgrade, I agree with @Lichtjaeger. There will be some change to the print head for the MMU but not a lot. I suggest that you do your MK3S+ as a stand alone and enjoy your printer. With the MMU, you have the option of starting with Sections 4,5, and 6 which is the assembly of the MMU unit itself separate from your printer. You can do that and have it ready to go when you decide to add it to your printer. I found the assembly of the MMU to be quite challenging and judging from others experiences on the forum, I am not the only one. 

RE: MK3S+ kit and MM2S upgrade order of installation?

Put the MMU aside for a few months.  @lichtjaeger is right.  Get used to the Mk3+ and establish good working practices before adding complications.  In time you will recognise and cure most comon issues with the base machine so that when issues arise with th MMU you will start looking in the right place.

The MMU is quite easy to use within its limitations once you understand your printer but users who rush in may have no-end of problems.

Cheerio,

RE: MK3S+ kit and MM2S upgrade order of installation?

I added the MMU a couple of months after I had purchased the MK3S+. I don't think you have to wait though. The MMU does seem to introduce a host of potential new issues but in my experience they are a different kind of issues than you will experience with the printer while optimising print quality. So, considering that there is no way that you're going to put the MMU aside for a few months anyway, I suggest to just go for it and install both the printer and the MMU. 

To answer your question: As said above by @silviatrilling, the changes to the print head when you install the MMU are not a lot. I think you'd be better off to do the complete printer installation and then the MMU installation. And, I would recommend to test the printer first before you install the MMU so that if you do run into any issues, you know it's not the printer.

One last thing: I found that a lot of the issues that come from the MMU require the changing or loading/unloading of the filament. Because the PTFE tubes feeding into the MMU are screwed in place this can be cumbersome. Then I found this mod that made this all much much easier. I can recommend it.    https://www.thingiverse.com/thing:3233579

Good luck 🙂 

RE: MK3S+ kit and MM2S upgrade order of installation?

I started with 3D printers in college in 1997 working with Stratasys machines and also developing a custom multi-material machine relying on 2 heads to work with 2 filaments simultaneously.  I currently have a Lulzbot Mini which I've been using since 2016 on which I upgraded the extruder.  So I'm not a total noob 

However, I have taken your advice to heart and will complete the printer first before I dive into multi-material

To replace my Lulzbot, I read a ton of reviews and watch a lot of YouTube videos and I was really impressed by what I saw about the Prusa. My budget locked me in the $1000 range. Now, with all of your warnings, I just looked at some of the poor reviews on this online store about the MM2S and am starting to get worried...

So excited by the immediate responses to my question on this forum, so I'm glad there is an active community.  I hope I am equally impressed by the printer once it is fired up

Thank you!

RE: MK3S+ kit and MM2S upgrade order of installation?

You’re obviously much more experienced than I am. I only started with 3D printing in 2018. 
With regard to the MMU2, I’ve seen a lot of the negative reviews as well, but I really like it. That doesn’t mean I never have a problem, but nothing I couldn’t solve. Just two weeks ago I did a perfect print with 4 colors and over 2000 filament changes over a 45 hour period. 

RE: MK3S+ kit and MM2S upgrade order of installation?

I would echo the admonitions to get the printer working and stable before even considering adding the MMU2S.

I went through the baptism by fire and steep learning curve of the MMU2S back in 2020.

I found the instructions to be less detailed, requiring more reading between the lines, than the instructions for the MK3S.

I also found the pieces to be less 'finished' than those for the MK3s, requiring some clean-up, chasing out of holes, etc.

I would suggest two upgrades right off the bat, and the pieces for this are in the Prints section.

1. Use a remixed manifold with Bowden tube fittings, rather than the stock manifold that simply clamps the tubes in place.

2. Install a DPST switch to kill the power to the MMU2s, breaking both the + and - leads.  This allows the machine to be used as a plain vanilla single-color unit without any futzing around.  There are two tapped holes in the MK3s frame which almost appear intended for this.

Dealing with the buffer, or finding an alternative to such, will be left as an exercise for the student.  😉

RE: MK3S+ kit and MM2S upgrade order of installation?

Posted by: @ehb

Now, with all of your warnings, I just looked at some of the poor reviews on this online store about the MM2S and am starting to get worried...

My MMU2S upgrade kit was delayed by a few weeks after I placed the order. During those weeks, I strongly considered cancelling the order because I started noticing people saying it just wasn't that good. Lots of load/unload failures being the primary problem. Someone linked a manifold above, I printed that before I built the MMU2S. I think that, along with replacing all of the PTFE tubing (4mm x 2mm ships with the kit, I used 4mm x 3mm) also helped. 

I regularly do 24h+ prints with thousands of filament changes with zero intervention. I've found that errors are rare exceptions. I only print in PLA and PETG. I do think that you will want to focus on having only one or two filament brands that you trust. The MMU is a little rougher on filaments than solo printing due to loading and unloading, so using brittle filaments can cause problems. It doesn't have to be expensive filament, but I wouldn't go for the bottom of the barrel stuff. I lean towards cheap-as-hell Hatchbox for PLA and Atomic Filament for PETG.

RE: MK3S+ kit and MM2S upgrade order of installation?

I want to thank everyone for all the awesome feedback and give a quick update.  I finished the build of the MK3S+ kit, updated the firmware and went through all the "preflight", "calibration", etc. exactly as described in the manuals. It all went smoothly.

My first test print, I could see that the nozzle was well above the surface, so it failed almost immediately and I aborted. 

I tried again. I used the "live Z" adjustment to bring the nozzle down.  It was going smoothly, but the test Prusa Logo still came off the print bed after the first two layers.

 i know this is a minor speed bump and I can't wait to get rolling. I ABSOLUTELY LOVE THIS PRINTER!  it seems to be an amazing combination of  hardware and software.  It runs efficiently and quietly.  The features are well thought out.

Does anyone have any suggestions about my first test print and proper Z calibration?  I did the calibration without the "Heated Steel sheet" on.  With a piece of regular white printer paper on the bed - that at some times had trouble staying put.

Should I recalibrate with the steel sheet in place?  Without a piece of paper to protect the bed?

Again - thank you so much! 

RE: MK3S+ kit and MM2S upgrade order of installation?

You definitely need to calibrate without the sheet of paper and with the steel sheet.

RE: MK3S+ kit and MM2S upgrade order of installation?

The Z calibration is very important to getting good prints.

I suggest getting it close with the built-in calibration routine first, getting the correct degree of 'squish' on the larger square, and then using any of several test prints (I prefer the 3x3 squares) to dial it in closer and to check for variations across the build plate.