Comment by ReptileMan
1 day ago
Reading about this, just makes me wish I has good 3d scan of their impellers to see how a simple 3d printer will deal with such mythical precision.
1 day ago
Reading about this, just makes me wish I has good 3d scan of their impellers to see how a simple 3d printer will deal with such mythical precision.
The materials that you could use in a 3d printer are not rigid enough.
The blades of the fans are fiber-reinforced, in order to have sufficient rigidity, even when very thin.
Only a 3D printer for metals could print something rigid enough, but such a metallic fan would be too heavy for a computer fan.
False, if you're printing PLA or something sure, but you can print all sorts of exotic fiber reinforced materials, and maybe if you're clever enough you can even use the anisotropy of the print to give you extra strength in the relevant directions. I'm not claiming that it's possible to 3D print noctua quality fans, especially on consumer FDM machines, but I think "inability to find a rigid enough material" is not going to be the failure mode, at least not on it's own. I could believe "inability to find a rigid enough material that can also get the required surface quality".
Noctua is awesome in a lot of ways, one of them is offering full CAD models: https://www.noctua.at/en/3d-cad-models
One of the first things mentioned on that page is:
> To protect our intellectual property, certain features – such as fan impeller geometries – have been slightly modified while remaining visually very close to the actual product.
So you do have to 3d scan them yourself if you're trying to print a copy.
Depending on what printers you have available I'll put in the work to get you a ~0.02mm deviation scan of a blade off a 120mm noctua fan I broke. I expect it to under-perform notably due to the surface texture and the lack of rigidity under load causing contact with the shroud walls at high RPMs, but I wouldn't bet my lunch on it, would be fun to find out.
The texture has substantial chance to actually help. Check golf balls.
It really does not have any chance to help. Golf ball dimples don't like magically make the thing better at air, if they did don't you think you'd see these sorts of features on fans or other airfoils to begin with?
You want dimples to create turbulent air that stays attached for longer, this INCREASES skin friction but since the golf ball is a bluff body it's friction losses are dominated by form drag, not skin friction. Putting dimples on a wing will drastically lower it's lift to drag ratio (which could in some cases be desirable, but it will absolutely not make the wing more efficient).
Of course all of this is moot anyway because the dimples need to be tuned to the Reynolds number you're expecting to operate at. Random surface imperfection wouldn't help even if it could help, which it can't.
Obviously better if you print slow enough. But the fans will be weaker and you won’t be able to pump out thousands every day.