Method of Measuring the Circuit Board Temperature During Drilling
Original Publication Date: 1984-Jan-01
Included in the Prior Art Database: 2005-Feb-02
During the drilling of circuit boards with laminated copper planes, a thermocouple is formed when the hard metal drill touches the copper planes. The resultant thermovoltage depends on the cutting edge temperature. For evaluation, the thermovoltage is derived from the cold end of a bared copper plane and from the drill, using a sliding contact system in which there is no additional thermovoltage. By selecting an appropriate copper plane, the temperature characteristics of the board can be localized. The drilling of circuit boards leads to a highly undesirable smearing of the epoxy resin at high drilling temperatures and to a caking of the bore walls of the copper planes. The drilling temperature depends on several parameters, such as time, speed, advance, cutting edge geometry, etc.