Patent ID: 6015249
Filing Date: 2000-01-18
Classification: B23Q,G01B,H05K,Y10T

Abstract:
A device for controlling the machining depth of a machine for machining multilayer printed circuit boards, comprising an operating head (11) movable by an electronic unit (16) with respect to a board (6) to be machined; said head (11) comprising a board holder device (21), and an electric motor (17) for a tool spindle (13); said electric motor (17) comprising a rotor (18) integrated with said spindle (13), and a stator (19) fitted to said head (11) and movable axially towards said board (6); air-cushion supporting means (53, 54) being provided between said rotor (18) and said stator (19); and further comprising a generator (24) for generating electric signals at a predetermined operating frequency and for sensing contact of a tool (14) on said spindle (13) with a conducting layer (9) of said board (6) to define a machining depth reference dimension, said stator (19) being connected electrically to said head (11) by an inductor (L) for insulating the stator (19) from said head (11) at least at said operating frequency; and enabling means (26) for so conditioning said control unit (16) as to feed said stator (19) to a predetermined depth (K) departing from said reference dimension so defined.