20K Ultrasonic Abrasive Assist Drilling
In the process of Ultrasonic drilling, material is removed by micro-chipping or erosion with abrasive particles. The tool is oscillated by a piezoelectric transducer and an electric oscillator at a frequency of about 20 kHz. The tool forces the abrasive grits, in the gap between the tool and the workpiece, to impact normally on the work surface, thereby machining the work surface.
During one strike, the tool moves down from its most upper position with a starting speed at zero, and speeds up to reach the maximum speed at the mean position. Then the tool slows down its speed and eventually reaches zero again at the lowest position. When the grit size is close to the mean position, the tool hits the grit with its full speed.
The smaller the grit size, lesser the momentum it receives from the tool. As the tool continues to move downwards, the force acting on larger grits increases rapidly, therefore some of the grits may be fractured. v Eventually, the tool comes to the end of its strike and grits with size larger than the minimum gap will penetrate into the tool and work surface to different extents.
Hard materials such as stainless steel, glass, ceramics, carbide,