International Business Machines Corporation

Francis S Poch

David Erle Houser

Robert Maynard Japp

James M Larnerd

Gregory A Kevern

Jeffrey L Lee

The present invention provides a structure. The structure includes a stack of sheets. Successive sheets in each pair of successive sheets of the stack are coupled to each other by a removable adhesive. The removable adhesive is also disposed on top and bottom surfaces of the stack so as to respectively couple first and second layers to the cop and bottom surfaces of the stack.

Drill stack formation

The present invention provides a method of temporarily adhering a stack of sheets together to facilitate drilling a hole through the stack of sheets. The method includes using a temporary adhesive that prevents burring while drilling a hole through the stack.

The present invention provides a circuit board having burr free castellated plated through holes. In particular, the leading edge of the plated through hole, that tends to produce burr formation during conventional profiling, is removed or pre-profiled to off-set the leading edge of the plated through hole from a surface of the circuit board.

Circuit board having burr free castellated plated through holes

The present invention provides a system for recording a heat exchange event within a drilled hole wall caused during a drilling process. In particular, the invention includes a thermal sensitive film placed in contact with a substrate which is to be drilled, which is capable of recording a thermal signature of the heat transferred during the drilling process. The result is a ring shaped signature whose thickness provides a direct correlation to drilling temperature. With these results, the integrity of the substrate surrounding the drilled hole can be inspected.

Apparatus for measuring the temperature of a circuit board during a

The present invention provides a method of creating a circuit board having burr free castellated plated through holes. In particular, the leading edge of the plated through hole, that tends to produce burr formation using conventional profiling methods, is removed or pre-profiled. The pre-profiled plated through hole is then profiled at a distance slightly off-set from the pre-profiled edge to further prevent burr formation.

Method of making a circuit board having burr free castellated plated

The present invention provides a system for recording a heat exchange event within a drilled hole wall of a substrate during a drilling process. In particular, the invention includes a thermal sensitive film placed in contact with a substrate which is to be drilled, which is capable of recording a thermal signature of the heat transferred during the drilling process. The result is a ring shaped signature whose thickness provides a direct correlation to drilling temperature. With these results, the integrity of the substrate surrounding the drilled hole can be inspected.

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Apalachin, NY, United States of America

Francis S Poch