| 摘要 |
Perforated plastic printed circuit boards having metallised hole walls are produced. Before the metallisation, the hole walls must be freed from resin deposits produced during drilling of the holes. This is performed using alkaline permanganate solution. The solution has a pH-value of at least 13 and a temperature of between 35 and 70 DEG C. In trials, a weight loss was firstly established in connection with the action of such a solution, followed surprisingly by a weight increase and thereupon once again by a weight loss. The treatment of the hole walls with the permanganate solution is terminated before the occurrence of the second weight loss phase. With printed circuit boards which have printed conductors made from insulated wire and cut through by the perforation, the insulation of the wire ends present at the hole walls can be removed simultaneously by the permanganate solution. The exposed wire ends are firmly connected to the metallisation layer during metallisation of the hole walls. |
