A New Approach to Outgassing Study of Plated Through‐hole Printed Boards

Outgassing of PTH PCBs at different stages of PCB production was studied with a modified IEC outgassing test, Draft June 1985, now included in IEC 326–2 Amendment No. 2, January 1988. Outgassing rate from single PTHs was quantitatively measured with a U‐tube manometer as a pressure of expanded steam escaped. Some technological parameters were taken into account and different comparisons were made: PCB production stage (drilling, copper and solder plating, reflowing) vs. outgassing rate, laminate thickness vs. outgassing rate. The contributions to outgassing of PTHs through PCB production, especially from copper and tin‐lead plating, are seen. On PCBs, drilled with different drills and soldered unpopulated on wave and drag soldering machines, outgassing faults were assessed. By multiple regression the relation between outgassing faults, hole wall roughness and plated copper thickness was calculated.