WERKWIJZE VOOR HET VERVAARDIGEN VAN VAN UITSMERING VRIJ ZIJNDE BORINGEN IN UIT KUNSTSTOF GEVORMDE GELEIDERPLATEN.

摘要

A method is disclosed for producing accretion-free holes with a diameter of less than 1.5 mm in circuit boards made of plastic. A hard metal drill is employed having a cylindrical chucking shank and a fluted twist section. A central axis of the twist section of the drill is moved eccentrically in relation to a central axis of rotation and therefore to a central axis of the drilled hole while drilling such that a widening of the hole occurs which is at least 20/ mu m but not more than 50/ mu m.