Patent · US Expired

Method of producing holes free of accretions in circuit boards made of plastic

US4190386A · kind A · utility

19Cited by

3References

3Claims

0Family size

Assignee

Siemens Aktiengesellschaft · DE

Inventors

Bernhard Brabetz · Munich, DE
Helmut Hackl · Munich, DE

Key dates

Filing date	Sep 15, 1978
Grant date	Feb 26, 1980
Priority date	—
Expiry date	Sep 15, 1998

Classification

Technology area (CPC Y)Emerging Cross-Sectional Technologies
CPC primaryY10T408/9097
WIPO fieldMachine tools
WIPO sectorMechanical engineering

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.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.