MMU3 Upgrade for Core One - Do you need to make the extruder updates? - Assembly and first prints troubleshooting

RE:

Marcolotto — Thu, 11 Sep 2025 16:04:50 +0000

I've already printed the parts and I've also installed the MMU on the Core One as the manual. I thought I had to change something in the Nextruder before starting the MMU. Oh God, I'm so dumb and confused :D

RE: MMU3 Upgrade for Core One - Do you need to make the extruder updates?

k1mu — Thu, 11 Sep 2025 15:51:24 +0000

Posted by: @marcolotto
Hello Guys
Where can I buy the parts to upgrade my NextRuder? I got an MMU3 from a friend, but it doesn't come with a box or a replacement part.
Thanks :)

Not something you can buy, but you can print: https://www.printables.com/model/531604-mmu3-printable-parts/files and look at x'CORE ONE & MK4 & MK3.9 Nextruder parts - R2"
Or, reach out to support and ask them how to buy the parts.

RE: MMU3 Upgrade for Core One - Do you need to make the extruder updates?

Marcolotto — Thu, 11 Sep 2025 11:18:26 +0000

Hello Guys

Where can I buy the parts to upgrade my NextRuder? I got an MMU3 from a friend, but it doesn't come with a box or a replacement part.

Thanks :)

RE: MMU3 Upgrade for Core One - Do you need to make the extruder updates?

darkmattermaker — Wed, 04 Jun 2025 20:58:48 +0000

Specifically the mod to the nextruder does two things:

1. adjusts the filament sensor to trigger when the filament enters the extruder gears which makes MMU filament loads more reliable.

2. swaps out the 3d-printed main plate with a main plate printed using a more robust process. This reduces wear on the main plate and helps it last long under potentially thousands of automated filament loads / unloads.

In short, @defsdoor is right, you want to do the mods.

RE: MMU3 Upgrade for Core One - Do you need to make the extruder updates?

gman — Wed, 04 Jun 2025 16:29:09 +0000

thanks! that clears it up

RE: MMU3 Upgrade for Core One - Do you need to make the extruder updates?

defsdoor — Wed, 04 Jun 2025 16:14:08 +0000

Yes - you will need to do that mod.

MMU3 Upgrade for Core One - Do you need to make the extruder updates?

gman — Tue, 03 Jun 2025 14:40:42 +0000

Sorry for the noob question but just ordered my first Prusa Core One and am about to order a MMU. Because I'm impatient I'm going to order an assembled MMU3 for the MK4 and the conversion kit instead of waiting for the assembled enclosed version.

The conversion instructions for the MMU3 Mk4-->Core One are straightforward but they did not reference the Core One Nextruder Mod for MMU3 functionality on this page

https://help.prusa3d.com/guide/9d-core-one-nextruder-mod_111779

Is that something I need to do before installing the MMU3 or do new Core Ones have the necessary mods built in?