Solder self-assembled micro axial flow fan driven by a scratch drive actuator rotary motor

This work presents the first micro-sized axial flow fan driven by a scratch drive actuator rotary motor. The eight fan blades are mass assembled using the surface tension of molten 4 mil diameter 63 Sn/37 Pb manufactured solder spheres. A sample size of 27 blade angles was measured with a mean assembly angle of 107.24/spl deg/. The actual mean of the manufactured solder sphere diameters was measured at 4.89 mils, yielding a, model predicted, mean blade assembly angle of 107.71/spl deg/. At resonance, the SDA motor can be driven at 50 RPM forward with a 2 kHz AC voltage of 30 V/sub 0.P/, and at 100 RPM reverse with a 3 kHz signal. For non-resonant frequencies, the SDA motor can be driven in a forward direction with linear speed control up to 180 RPM using driving signals from 75-150 V/sub 0.P/. Fluid movement by the fan was also experimentally demonstrated.