Look closely
If you look closely at the metal shroud on a Dyson Big Ball machine, you'll see it's perforated with tiny holes - over 30,000 of them, in fact. Dirty air gets sucked through the mesh, filtering out all but the finest particles of dust. To be just right, each hole has to be individually etched with acid, and measure less than 250 microns wide... that's less than half the size of a single grain of rice.