New Methods of Surface Area Measurement and Current Density Control in PCB Manufacture

New methods of surface area measurement by electrolytic means have been introduced into the UK by PMD Chemicals Ltd of Coventry. Two instruments, known as the DIM and MIM systems respectively, are available. The instruments differ in their method of measurement and applications, but both measure the conductive surface area of photo‐resisted boards to a high degree of accuracy and can convert this area measurement via an interface unit to a rectifier current output, thereby controlling plating current density.