Method of producing holes free of accretions in circuit boards made of plastic
AssigneeSiemens Aktiengesellschaft
InventorsBernhard Brabetz, Helmut Hackl
Life of this patent
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Abstract
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.
Claims3
A method of producing accretion-free holes with a diameter of less than 1.5 mm in circuit boards made of plastic, comprising the steps of:
- providing a hard metal drill having a cylindrical chucking shank connected to a fluted twist cutting section having a central axis, rotating said fluted twist cutting section about an axis and feeding said fluted twist cutting section along said axis relative to a circuit board, supporting the fluted twist cutting section so that its central axis rotates eccentric to said feed axis of the fluted twist cutting section by a distance sufficient to drill a hole having a diameter of at least 20 micro-meters but not more than 50 micro-meters wider than the maximum diameter of the fluted twist cutting section.
Dependencies are inferred from the claim text.