The Black Hole - Core One/+ Custom Filtration

The Black Hole

Introduction

As some other people online have lamented before, when you install the advanced filtration unit onto your Core One, you HAVE to use the filter fan to cool your chamber, even when printing filaments that don't strictly require filtration (PLA/PETG etc.). (I'm mainly targeting VOCs here, since afaik, if the room the printer is in has moderate airflow, ultrafine particles don't tend to cause issues, except under heavy use)

This design solves that problem!

Parts list

Socket Hex Screws:
M3 x 35 x4 (Filterstack-Manifold)
M3 x 25 x4 (Fan Shroud-Fan Housing)
M3 x 20 x4 (Filter-Fan Shroud)
M3 x 16 x7 (Fan, Manifold-Printer)

Skateboard bearings (608-XX) x2

Foam Weather Stripping 3mmx6mm 1 roll  (Amazon)

Alveo BLHP2432-H24 (120mm centrifugal fan) 1x (Alveo)

Molex Clik-Mate 4 pin connector or wire assembly 1x (Mouser) (Also available elsewhere)

Activated Carbon Pellets (Amazon)

HEPA filters 130mm x 50mm x 5mm (Amazon)

Print Settings

The Filter piece consists of 1 main body and 2 modifiers, set the following settings in these modifiers:

• Material: PETG is recommended (as the chamber CAN get to 55C which MIGHT soften the plastic)

• Top Shell Layers: 0

• Bottom Shell Layers: 0

• Infill Density: 30%

• Infill Pattern: Triangles

None of the others REALLY matter, though I'd suggest a minimum perimeter count of 3, particularly for the screw holes as you do want them to be strong.

Assembly Guide

 There's an assembly guide PDF added below

Features

Manifold

This manifold effectively guides your exhausted air through one of two paths

1: Out the back

Thanks to the exhaust flap on the back, even minimal positive airpressure inside the manifold (produced by the stock chamber fans) opens up the path for hot air to leave the print chamber with minimal resistance

2: Through the filter

With the chamber fans disabled, the filtration fan can drop the pressure in the manifold far enough, to where the exhaust flap closes and all extracted exhaust air is pulled through the filter

Filter case

Using a relatively cheap, readily available HEPA filter and some activated charcoal pellets we can filter the exhaust fumes and trap most of the VOC's that would otherwise be freely exhausted. This part of the design was inspired by another made on here by @manmac

Fan Shroud

This adapter plate helps guide the air through the filter and into the filtration fan.

Fan Housing

Real simple housing to mount the fan to the rest of the module.

No heated inserts?

I often see prints that need heated inserts when screws are needed. This is a fine solution as is, but if you don't want to use them/don't have them or the tools to install them, this can become a bit of a hurdle and an investment to start a project.
This is why I decided to make this entire project work with special geometry (link to a video about this geometry, all credit belongs to Thomas Sanlanderer of the Made with Layers youtube channel) that allows for a clean screw install, without the need for any extra tools! 

Custom firmware

By default, Prusa's Core One firmware disallows the chamber fans to dynamically control the chamber temperature, meaning you'd have to toggle the current filtration setup from “Advanced Filtration” to “none” everytime you change from a filament that requires filtration, to one that doesn't and vice versa.

I was not satisfied with this as the final product, so I went ahead and made my own firmware. This firmware lets your printer decide which fan it wants to use to control the chamber temp and if they need a minimum PWM or not, for more information on/to download the custom firmware feel free to check out my Github Repo

The custom firmware is NOT neccesary to make this model function! It just makes your printer swap between filter and chamber fans depending on what your filament requires according to it's own database!

Disclaimer

This firmware is provided "as is" under open-source principles.
By downloading, installing, or using this firmware, you agree that you do so at your own risk.
The authors and contributors make no warranties, express or implied, and accept no liability for any damage, loss, or injury arising from its use, including but not limited to hardware damage, print failures, or safety hazards.

Before flashing or modifying your printer, ensure you fully understand the configuration and safety implications of these changes.