A Modern Approach to Drill Optimisation

The drilling process in the manufacture of printed circuit boards is one where there is a wide variation in the optimum parameters used by each printed circuit board manufacturer. The reason for this is probably due to variation in the definition of what is required and noise in the experiments used to determine them. The author has used a fresh approach by combining the use of Taguchi Methods to design a fractional factorial experiment together with a fibre‐optic temperature probe to measure the temperature of the drill bit under different experimental conditions. The Taguchi experiment demonstrates: (1) The high temperature rise with stack height; (2) the difference between woodpulp and phenolic back‐up/entry material; and (3) those parameters that have little effect on drill temperatures. Further work demonstrates: (1) The variation between drills and drill suppliers, and (2) how the use of a dry lubricant can minimise the variation in drilling temperature as well as extending drill life and increasing productivity.