Preparation of Small Diameter Holes in Printed Circuit Boards for Electroless Copper Plating Using a Jet Pumice Machine

Due to problems experienced at the deburring stage of drilled 0·013 in. diameter holes, where the holes became blocked with deburring brush fibres, it was necessary to replace the use of traditional deburring techniques for the preparation of these drilled holes prior to electroless copper plating. In order to achieve this, a jet pumice machine was purchased and trials were conducted using various grades of pumice powder and different machine parameters. The purpose of these trials was to determine the optimum machine parameters for the task, such that burr‐free hole peripheries were achieved in conjunction with a surface finish suitable for electroless copper plating prior to dry film lamination.