3d printed fan ducts

msystems

Master of Cramming
Original poster
Apr 28, 2017
550
952
I've never really been impressed by any desktops Dell ever made, but they wisely had fan ducts on their machines:


A fan duct is the most effective way to reduce heat and noise and therefore improve reliability.
It lowers the fan rpm requirements by routing air to/from a specific place. Less airflow is wasted by ineffective circulation and by not being routed against heat-generating components.


Look at most full ATX tower designs, what do you see? 2+ 120mm intake fans usually.



I actually have one of these Antec cases and the airflow is good. But how much of that air simply goes to waste?
Probably a lot.






With 3d printing we can now fabricate ducts to our specific applications.
A quick browse of thingiverse finds a few designs, made to spec:


"A duct that adapts a 120mm fan to blow out the PCI/ATX expansion slots. The exhaust opening takes up 3 slots, with a 25mm-thick fan taking one more slot. The combined assembly takes up exactly 4 slots of width. The bottom of the duct should clear both PCI-E and taller conventional PCI slots.


You can mount the fan with fan screws or cable-ties.


Print with the largest flat side (the side opposite the one where the fan mounts) on the build plate. Supports are needed for a very small overhanging part of the PCI bracket. In Cura, the setting for supports is "Touching Build Plate". This keeps it from generating supports between the vent fins, where they are difficult to remove. If you don't have this option, it might be better to turn off supports altogether and let the bracket sag a little."



"This is a 70-50mm adapter"


"his duct mounts a 120mm Lepa fan to a 70mm stock AMD cooling fin heatsink. this one was printed in red madesolid pet+"

These are only a few meager examples of the possibilities. But there is great potential use for this in any fully-enclosed SFF case where ambient air is insufficient and fan size is limited and noise is not desirable.

Any suggestions are welcome on the software, design, materials, and the best vendor to print it and to collaborate on fan duct projects for existing SFF cases.
 
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entropy

Caliper Novice
May 17, 2017
33
19
I looked into 3D printing a case. I think PC-ABS seems like one of the best plastics, because of strength and temperature resistance. The downside is that its harder to print than PLA or ABS alone. Metal would be too expensive of course.
 

iFreilicht

FlexATX Authority
Feb 28, 2015
3,243
2,357
freilite.com
For vendors, shapeways and i.materialise are obvious choices. The latter offers cheap ABS filament printing, but I'd recommend to always compare quotes from both vendors on parts you upload. Ideally, print locally or yourself, that will allow you to tweak designs much quicker and might be cheaper as well.

In general, material doesn't really matter here. Even PLA should work perfectly fine, its melting point is at 150-160°C, nothing in your PC should be that hot. Strength might be a point to consider, but fans aren't really heavy equipment, so increasing wall thickness of the duct should be enough in any case to support the weight your fan has.

Collaboration might be sensible in some cases, but I think you can't do much more than upload a duct you've tested with your setup on the Resources section here or a place like thingiverse. If you want to get very professional, you could make a parametric model (think a duct from the LZ7s intake to the CPU cooler that accounts for different fan sizes and socket positions), but at that point you invest a lot of time to account for many different parameters, so selling via a vendor might make more sense than just sharing it for free.

For software, you can really use anything that can export an .stl file, Solidworks, Inventor, Fusion 360, FreeCAD, doesn't really matter. I don't know about tools specifically designed for printing, but there might be some.
 

rahl07

Caliper Novice
Nov 28, 2017
33
23
AFAIK, PLAs biodegradability is a myth. It is made from renewable resources, though, so still better than ABS.

Yes, and no. If you're composting it properly and the temperature is high enough, it biodegrades pretty rapidly (in a matter of months). However if the specific condition for PLA breakdown aren't met, it just sits in a landfill and rots right along with the other slow-decaying plastics. We've actually used PLA balls down-hole in oilfield to perform tasks, then kept them up to temperature with super-hot water and high pressure to break them down once the task is complete.
 

iFreilicht

FlexATX Authority
Feb 28, 2015
3,243
2,357
freilite.com
Yes, and no. If you're composting it properly and the temperature is high enough, it biodegrades pretty rapidly (in a matter of months). However if the specific condition for PLA breakdown aren't met, it just sits in a landfill and rots right along with the other slow-decaying plastics. We've actually used PLA balls down-hole in oilfield to perform tasks, then kept them up to temperature with super-hot water and high pressure to break them down once the task is complete.

Very interesting, thanks a lot!