"Micro Cooling Fan" blade spacing: the distance between the blades is too small, will result in flow disturbances, increasing the friction surface of the blade, reducing the efficiency of the fan; the distance between the blades is too large, it will lead to increase in pressure loss, inadequate pressure cooling. fan blade tip clearance: how to adjust the gap that exists between the blades and the frame is "Micro Cooling Fan" design gap is a major problem here is too small will make the air flow and the blade, frame friction, increased noise. ; increase the gap is due to the air flow and other effects flyback ear reduce fan efficiency - the gap increases by 1%, the total pressure drop by about power 2% "Micro Cooling Fan" Blade Angle: angle of the greater pressure between the upper and lower leaf surfaces. The greater the difference, the greater the pressure at the same speed; but the surface pressure, may have reflux phenomenon, but the performance and therefore reduce the fan blades should also enhance the inclination within certain limits.