Magnetic HEPA/carbon filter system, PTFE guide and thermistor mount

A modular filter system for the Voron 2.4. It also features a low-friction filament/PTFE tube guide and a mount for a chamber temperature sensor.

Design Goals

• Modularity and easy maintenance
• Jam-free filament guidance via PTFE tube
• Integrated temperature sensor for the print chamber

Solution Strategy (In Brief)

I wasn’t sure how much activated carbon would be enough to make the filter nearly odorless — and I believe many people will want to run their own experiments here. That’s why I opted for magnetic connections: they make the system easy to modify, maintain, or expand.

Filament routing had also been a long-standing issue. Feeding the filament directly into the extruder doesn’t work well with a filament changer or motion sensor. But when using a PTFE tube (similar to routing power or data cables — next project!), you often run into the problem of the tube dragging uncontrolled through the chamber, especially at higher Z-heights.

This design solves that — at least for the filament tube. Thanks to the GE5C spherical bearing, the PTFE tube can move freely in all directions and can be easily pushed in and out of the enclosure. I also tested solutions without a bearing and with PTFE tube connectors, but the GE5C joint clearly performs best.

And since there was still a bit of space left — and I originally had the illusion of controlling chamber temperature via the exhaust air — I integrated a chamber temperature sensor as well. I tested several positions (near the bed, near the gantry), but the current spot — between the air outlets — turned out best. Not only is it visually cleaner, but when the exhaust is running, the temperature reading is closest to the actual chamber temperature — at least more accurate than typical alternatives.

In the end, the modular design offers several advantages: filters or activated carbon can be replaced easily, and the structure invites you to design your own add-ons — for example, to use different fans or HEPA filters. Just be careful: the standard Voron magnets (Ø6×3 mm) don’t hold infinite weight — especially when side-loaded. So... don’t overdo it. 😉

Assembly Tips (Bullet Style)

• Gather all parts from the BOM
• Print at least one of each per filter side:
  • Activated carbon box
  • HEPA filter box
  • 60×60×28 mm blower fan holder
  • Exhaust elbow (air duct top part)
• Print the front and back mounting brackets (I used black)
• Install all magnets, screws, and brass inserts
• Make sure magnets are glued in flat and flush — you have only 0.2 mm of tolerance!
• Don’t forget the GE5C joint (you can experiment without it, but it’s worth including)
• You probably have a spare V6 heater block thermistor lying around — perfect for this
• Use leftover or new foam rubber sealing strips (5×1 mm) from your Voron build:
  • Cut four pieces per box and apply them precisely as shown in the photos
  • Take your time — sealing quality directly impacts filter performance
  • Apply sealing foam around the exhaust cutout on your back panel (probably already present from the original setup)
  • Also apply sealing foam to the exhaust duct’s front-facing mounting surface
• Add a few M3 T-nuts — installing them the first time is a bit fiddly, but once in place, the system is very stable

Material Recommendations

Use PETG, ABS, or ASA — not PLA, as it’s too temperature-sensitive and will deform over time.

BOM

• 2x 60×60×28mm Radial Fans (e.g. GDSTIME)
• 2x HEPA Filters, 80×40×15mm (e.g. available on Amazon)
• 1x GE5C Joint for low-friction guidance of the PTFE filament tube (e.g. FUSHI)
• 1x Cheap V6 HeaterBlock Thermistor, 3×15 mm
• Magnets, Ø6×3mm (standard Voron size, strong N42, N52)
  • 8× per FilterBox
  • 4× additional for top and bottom parts
• Sponge foam rubber tape, 5×1mm
  • For each FilterBox top and exhaust part (apply precisely)
• 8x M3x8mm SHCS
• 6× M3×12mm SHCS
• 2x M3x30mm SHCS
• Curled Brass M3 Inserts, M3x5x4 or x5mm (standard Voron spec)
• 4× M3 T-Nuts

Changelog

• I added an adapter so you can use a high-pressure, 80-mm axial fan of your choice. For example, you could use an Arctic S8038-7K. Be aware that you must either run it at high RPMs or use minimal carbon filter material.
• I added a 80x80mm fan diffusor for experiments
• I added a special HEPA filter box module with an nearly open floor

Love my 3D models? 

If my designs have helped you print something awesome or inspired your next project, consider supporting my work! Your kindness fuels my creativity, keeps the filament rolling, and helps me share even more free/pay-what-you-want models in the future. Every coffee counts! 

→ Buy me a coffee ☕☕☕