1. Preparation

Relevant for:

MMU3

Last updated 6 months ago

Difficulty

Moderate

Steps

Available languages

Step 1 Introduction

⬢In this guide, we will be upgrading the MK3S+ MMU3 setup into MK3.9/ MK4 MMU3.

⬢Make sure your MK3.9 / MK4 printer is fully assembled and tested.

⬢MMU3 installation requires extruder modifications. However, we need to make a few other adjustments before proceeding with that.

⬢Let's quickly review the key points we'll cover in this guide:

Step 2 Buffer Printable parts INFO

⬢The Original Prusa MK3S+ MMU3 upgrade kit to MK4/MK3.9 includes some printed parts.

All the MMU3 printable parts are available at Prusa3D.com Printables profile

More info is available at: Prusa3D.com/prusa-i3-printable-parts/

⬢However, if you are upgrading an MK3S+ version of MMU3 that was shipped before April 2024, you will need to reprint these files:

⬢5x MMU3 BUFFER2

Step 3 Electronics INFO

⬢The MMU3 requires a specific cable for Einsy-based (MK3S+) and xBuddy-based (MK3.5, MK3.9, MK4) printers. When moving MMU3 from an MK3S+ to an MK4, you must switch to the appropriate cable.

⬢While working on the electronics, you can upgrade the electronics cover to the newest version, in case you have the older one in place.

Step 4 360mm PTFE and FESTO fittings removal

⬢Remove the PTFE tube between the printer and the MMU unit by undoing the FESTO fittings.

Set it aside so that it doesn’t mix up with the new parts. These FESTO fittings will be replaced for the new ones included in the kit.

The 360mm PTFE tube will also be replaced, as it is considered a consumable item.

⬢Various versions of the fittings have been used in MMU units or with other Prusa products shipped before April 2024.

⬢However, the MMU3 on the MK4 printer requires the latest evolution of the fitting, which has an internal diameter of 2.6mm.

Step 5 MMU Disconnecting

⬢The MMU3 unit needs to be removed from the printer.

Make sure the printer is turned OFF and unplugged from the wall outlet, before starting to work on it.

Make sure there is no filament loaded.

⬢Remove the MMU3 unit from the printer by lifting the back of the unit up.

⬢Open the printer’s electronics box and remove the MMU3 power connectors. Re-tighten the terminals afterwards.

⬢Disconnect the MMU data cable from the Einsy board.

⬢Leave the neighboring IR Filament sensor cable in place.

Step 6 650mm PTFE removal

⬢Disconnect the 650mm PTFE tubes from the MMU unit.

Push the collet in and hold it. Push the PTFE tube in, then pull it out to remove it easily.

⬢Disconnect the 650mm PTFE tubes from the Buffer.

Save them. We will re-use these PTFE tubes.

Step 7 Spool holder INFO

⬢Remove the 650mm PTFE tubes from the spool holders.

⬢You have one of these two spool holder versions:

⬢

The older vacuum-formed spool holder.

If this version works well for you, you can continue using it.

⬢The injection molded spool holder.

Your kit includes an updated version of these spool holders, featuring wheels made from POM instead of ABS.

If your MMU3 kit was shipped before April 2024, we recommend upgrading the injection-molded spool holders to the updated version.

Step 8 Continue

⬢Continue to the following chapter to upgrade your MMU3 unit.

1. Preparation

1. Preparation

Step 1 Introduction

Step 2 Buffer Printable parts INFO

Step 3 Electronics INFO

Step 4 360mm PTFE and FESTO fittings removal

Step 5 MMU Disconnecting

Step 6 650mm PTFE removal

Step 7 Spool holder INFO

Step 8 Continue

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