Patent ID: 8226336

Claim:
A system for detecting an interface between first and second materials having dissimilar electrical characteristics and in intimate contact with one another, the system comprising: a drilling machine having a drill bit for drilling a hole through a portion of each of the first and second materials without separating the first and second materials, the portion of each of the first and second materials not including a hole prior to the drilling; an electrical circuit completed through the drill bit and including each of the first and second materials, wherein electrical conditions in the circuit are responsive to changing electrical characteristics of the circuit as the drill bit is advanced into each of the first and second materials; and a monitoring element associated with the electrical circuit and, based upon the changes in the electrical circuit, adapted to detect an interface between the first and second materials; and wherein the drilling machine is configured to: drill through the first material at a first rotational speed and feed rate for the drill bit; enable a rotational speed and feed rate of the drilling machine to be adjusted to a second rotational speed and feed rate as the drill bit approaches the interface; and drill through the second material at the second rotational speed and feed rate.