SV08 Quiet Filter and Cooling Fan box.

This design is part of my SV08 noise reduction project. The enclosure provided by Sovol looks nice but adds it own noise and the exhaust fan/filter is not good for ABS. 

I wanted a solution that allowed me to print ABS with low fumes and also print PLA with the enclosure doors closed. 

My fan box replaces the rear glass panel. The three fans suck air from the enclosure into a cavity filled with active carbon filter pads before expelling the air in to the room. Three fans means they can spin slow and quiet.  The cavity inside the box is large, plenty of room for carbon filter pads which are cheap.  I used PUREBURG Carbon Filter,Cut-to-Fit Carbon Pad 16 x 48 inches for Charcoal Sheet fits Range Hoods Furnace Filters, Food cycler filter. Kitchen Compost Bins Filter removes Odor VOC Replacement,1-Pack : Amazon.co.uk: Home & Kitchen, cut to length and folded 5 times.

The fans are ARCTIC P12 Max - PC Fan, High-Performance 120mm Case Fan, PWM controlled 200-3300 rpm, Optimised for static pressure, 0dB mode, Fluid Dynamic Bearing - Black : Amazon.co.uk: Computers & Accessories. They are practically silent  up to 50% speed for printing ABS. They are only a bit noisier when cooling for PLA. They work well to push air through the filter.  When they are at maximum speed you hear white noise through the filter - it isn't annoying and the filter blocks noise from the printer itself.

These are 120mm 12V fans, they could be controlled by Klipper - but that is a future project. I used a simple controller Driver Module, DC 12/24/ 48V PWM 4 Wires Fan Temperature Speed Control Governor Display Module Driver for PC Fan/Alarm : Amazon.co.uk: Business, Industry & Science. I had to change the fan connector on the pcb to be compatible with PC fans. The temperature sensor for the enclosure fits through a hole in the fan box. The fans are wired in parallel  - I used a 4-cable  to join them up. The excess wires can be pushed back in to the fan box and hidden behind the control board.

The interior of the fan-box is also line with 1cm thick noise reduction foam. I also put the foam between each fan to kill any vibrations. I used this Pamatio Car Insulation Soundproofing Mat, 10mm Thickness Self-Adhesive Auto Heat Deadening Sound Insulation Roll, 200 x 50 cm (Roll) : Amazon.co.uk: Automotive with the foil peeled off.

The box is printed in three parts, I chose PETG (PLA will probably get too soft). It uses about 1.4kg filament and takes about 27-30hrs for complete print.

I've used M3 heat-inserts to secure each section of the box together. It's simple to open the box and change filters if required.