Universal HEPA Filterbox (Alveo One & Klipper compatible)

Why a Filterbox?

We love 3D printing, don‘t we? The only thing is that research shows, it is not necessarily good for your health. You can smell it, and when you smell something, then something is in the air which should‘t be there. Long story short: There are particles, which will settle into your lungs and can cause severe health issues.

If you‘d like to go deep: https://all3dp.com/1/3d-printing-emissions-air-quality/

This is a great article with studies linked - highly recommended. 

Turns out: You can filter air to reduce the harmful stuff. Alveo3D has a ready to use solution to do this: the Alveo One. This is a kit with filter, electronics, fan, and everything you need, when you are able to print the plastic parts yourselves. They are designing filters for industrial solutions, for hobbyists (probably like you), and for companies who sell printers. It is worth mentioning, that also Prusa went for the Alveo3D filter system with their MK-enclosures. If you buy the Prusa filter kit for the enclosure, you will basically get an redesigned Alveo One. 

So Alveo3D seems quite a trusted system which hopefully will not vanish from the market in 5 years. I decided to equip my RatRig VCore3 Enclosure with this system. There are two ways of filtering the air:

1. circulate the air inside the enclosure
2. vent the enclosure through the filter

There are several pros and cons for each way to go, listed here.

As my printer enclosure is significantly warming up during printing, due to the huge heatbed and i‘d like to keep a constant temperature, this was my main argument for option 2.

Why another Filterbox-Design?

The AlveoOne filterbox may be good, but requires supports during printing. Also, the design from Alveo uses a dedicated power supply and electronics board for the fan. As i will power the fan from my BTT Octopus board i don‘t need this. In the future i will add an additional temperature sensor for constant temperatures, controlled by Klipper. Also i wished for a more modular design with screws as connecting elements.

The Alveo Filters seem to be quite trusted, so in the end i decided to buy the original Alveo filters and the fan from their webshop and design the filterbox myself. Important: Don‘t use a standard 120mm fan! While the fan looks similar, it is designed to build up enough pressure to push the air through the filter.

Printing

I recommend:

ABS (prepare for warping), PETG should be also fine

4x0,45mm perimeters

0,2mm layer height

25% infill

The filter protector will snap into latches and needs to be flexible. This depends on your filament. Scale this part in Z when flat on the printbed, to find your perfect flexibility. I scaled mine to 1,5mm thickness.

All printed in Polymaker PolyLite ABS

Post-Printing

Drill or poke the covered holes, clean the print, check all your parts fit together

Assembly

Glue rubber seal

The rubber seal prevents pressured air from escaping the filter. I used Uhu Plast Special to glue the seal into place. There is a little grove i prepared on the printed part (fan separator) for the seal to sit in. You need to seal both sides (filter and fan) of the fan separator.

Cut printer enclosure

Use the cutting template to cut your enclosure. If you have the luxury of CNC - i packed an svg file. Hand-Tools are also fine. I designed all parts with plenty of tolerance. If you transfer the template by print and paper, always measure the reference after printing!

Put it all together

Be careful when tightening the screws, they can break your parts.

Additional Material

• 4x M3x40 cap head screw
• 8x M5x25 cap head screw
• 8x M5x16 cap head screw (screw length depending panel thickness - mine is 4mm)
• 4x M3 hex nut
• 16x M5 hex nut
• 3mm round rubber seal (approx. 1m)
• Alveo3D P3D Filter
• Alveo3D High Pressure Fan

Klipper

I use this filter to keep my enclosed printer at a certain temperature. Together with an additional temperature sensor (DS18B20) attached to my Raspberry Pi i can use the builtin Klipper temperature fan to automatically keep the enclosure at preconfigured temperatures.
https://www.klipper3d.org/Config_Reference.html?h=temperature+sens#ds18b20-temperature-sensor
https://www.klipper3d.org/Config_Reference.html?h=temperature+sens#temperature_fan