| 摘要 |
PURPOSE:To select reasonably a substrate producing few smears by drilling a multilayer printed circuit board by a worn drill under the condition heated to various temperatures to evaluate smears from drill temperature and an amount of produced smears. CONSTITUTION:Compressed air introduced through a hose 3 is heated by a hot air gun 4, and heated air is blasted to a worn drill 2 to heat it. Immediately after heating for about one minute, a multilayer printed circuit board 6 is drilled under a predetermined condition. An amount of produced smears is evaluated by this method so that the multilayer printed circuit broad producing few smears can be easily selected, and the improvement and development on resin can be promoted. |
