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Ultrasonic Drill

The Ultrasonic/Sonic Driller/Corer (USDC) drills hard rocks such as granite or basalt, while extracting debris through an ultrasonic transport up the drilling shaft. This device was developed by JPL scientists and engineers from Cybersonics, Inc. Its floating head uses high frequency ultrasonic vibrations, produced by piezoelectric wafers, to create a hammering action. The head mechanism is a mechanical frequency transformer, and the drill bit operates with a combination of both ultrasonic and sonic frequencies. The transformer converts the 20 kHz ultrasonic drive frequency to a combination of the high frequency drive signal and a 60-100 Hz sonic hammering action. The drilling mechanism requires the simultaneous presence of both frequencies to work.

This USDC requires low power (3-4W), low axial preload (3-10N), and weighs a mere 0.4-kg. It is highly tolerant of misalignment, does not require sharpening and can be adapted to operate in both cold or hot temperature extremes. Since the drilling/coring bit does not turn, in-situ sensors can be integrated into it. As a result of the motions involved with this type of drilling, a hole is created that is slightly larger than the bit diameter. This reduces the chances of jamming so long as the integrity of the hole is maintained, which helps avoid a key problem encountered in conventional drilling operations.