Prusa i3 MMU2 Filament Buffer

This is the 5th addition to the Prusa i3 family of printers and adds MMU2 support to the*Enclosure*.

Prusa's i3 MMU2 unit is essentially an auto loader for up to 5 different filament3. This supports printing objects in multiple colors and/or the use of soluble support material.

This Component was optimized to address the following goals:

• Minimize space required,
• Mount on the Enclosure referenced below,
• Minimize the Filament path length,
• Minimize Filament Drag,
• Minimize the difficulty loading filament into system,
• Minimize number of printable objects.

The other additions are:

• Enclosure

https://www.thingiverse.com/thing:2396990

• Print Server

https://www.thingiverse.com/thing:2401423

• HEPA Filter

https://www.thingiverse.com/thing:2394452

• Spool Holder

https://www.thingiverse.com/thing:2398480

Print Settings

Printer Brand:

Prusa

Printer:

i3 MK3 MMU 2

Rafts:

Doesn't Matter

Supports:

No

Resolution:

.25mm

Infill:

20%

Filament: Amazon PTEG/PLA Orange/Black

Notes:

PTEG was used only because it was available when the prototyping occurred. PLA should have the necessary strength in the alternative.

How I Designed This ===================

Overview

2 July 2019 Update:
BASE (v1.2) was revised to include an additional forward curved PTEG path to accommodate filament spools that are positioned well forward of the aft edge of the enclosure. See Dry Mount filament buffer in a separate file.

This Component consists of 3 parts with an additional two optional parts for removable mounting.

**BASE*

This part provides has the following features: 1. Bracket to directly mount the component to a vertical surface or to bolt to*Slider* part to facilitate easily removal of the component from the mounting surface, 2.*Wheel* axle, 3. 5mm path through the structure through which a length of PTFE tube is inserted to guide the filament from the spool to the*Buffer, 4. Side and Back ofBuffer* as required to capture the unloaded extra filament. **Top* 1. Mounts to the base using 5 M3x7 and 1 m3x20 screws 2. Contains 5mm Filament Exit path suitable for PTFE tube insertion 3. Boss for mounting PTFE Tube quick disconnect. The Quick Disconnect must have 5mm threads and accept 4mm PTFE tube **Wheel* 1. Wheel accepts 608 Bearing which is manually pressed into the*Wheel. The opening in the wheel has 4 lobes that are slightly smaller than the bearing OD but will compress to accept and secure the bearing, 2. The wheel thickness is suitable for one filament loop. The sides of theWheel* are chamfered to centered the filament. **NOTE:*

PTFE Tubes must be inserted into the Input and Exit pathways in order to reduce overall filament drag. Without these tubes filament loading and extrusion will be unreliable.

Custom Section

Attribution:

This work was inspired by kommisar as illustrated in: https://www.thingiverse.com/thing:3228827

This work takes fro kommisar the idea of filament buffering using a loop in a compact body. That design required the Buffer to be placed relatively inline with the printer and, like Prusa's Buffer required considerable space. It also consists of a large number of parts, complicating the printing and assemble of the unit.

Category: 3D Printer Accessories