DIY Ventilation for 3D Printer Enclosure

Fan

Decided to use PC cooling fans as they're quiet and cheap. 

PC fans are usually PWM fans which means the PC's processor can control the speed of the fan.  There's 4 wires but you only need to wire up positive and negative to a 12 volt power supply, if you don't wire up the 2 control wires the fan runs at 100% which is perfect for our use.

Ducting

I wanted to try and use a small diameter duct so I got this piece of vacuum cleaner hose and designed the connectors to fit the profile. Measure the ridges and grooves of the pipe, then in CAD sketch the profile and do a revolve, it's fairly easy.

The trick to fitting the pipe is to put a fold in the pipe then insert into the connector. Once in push the walls back out and it's virtually impossible to pull out.

Panel

For the panel in the Voron's tophat, I didn't have any more acrylic sheet to cut a hole in but then I had a brain wave and realised it'd be easier to print a panel in ABS and you can design in attachment points.

The Voron panels can be printed on a 220x220 printer bed.

Window Outlet

I designed a push fit connector to connect up to a window blank.  This blank is custom to my window, so you probably need to customise for your window. I've included the CAD files with all the STL files for the parts.

To cover the rest of the window gap I've cut a long strip which connects up to my window blank.

Results

So how did it go?

Welllll....it kinda worked but it didn't move as much air as I hoped. And maybe there was some leakage too.

It looked cool with the LED lights.

From the smoke tests you could see that it is working but when all connected you could still smell the print.

Version 2

Back to the drawing board...I did some research and decided to get a more powerful PC fan. Cheapest is not necessarily the best. Checked the specs closely and spent an extra $10 bucks.

I thought the fan enclosure might be too restrictive so designed something more funnel'ish.  But this had strange results and seem to suck the air backwards !  Realised there's alot more going on with the air flow in these fans.

Found Major Hardware's YouTube channel where he tests PC fan designs and his best performing fan was the Cheetah by Nesto.  Nesto used a directional duct after the fan which channels the rotating air.  Created one of these and it had an amazing effect and even the cone was pumping out air !

For the ducting, decided to give in and play it safe with large bore 100mm duct.  

Version 2 Results

And the results....

It works really well.  The big ducting looks a bit nuts on such a tiny printer.  Get absolutely no smell now.

Another advantage is that it keeps the enclosure temperature down to 35 degrees so I don't run into problems printing PLA and the extruder squishing the filament.

Also noticed that the Raspberry Pi temperature stays around 39 degrees compared to getting up to 60 degrees before the fan. So air must be being drawn through the electronics compartment at the back keeping the Pi, SKR controller board and stepper motors cooler, which has got to be a good thing.

I'll be building another one for my larger printer enclosure.