| 摘要 |
The device includes an operating head (11) movable by a control unit with respect to a board (6) for machining; the operating head (11) includes a board holder device (21) and an electric motor (17) for a tool spindle (13); the rotor (18) of the motor (17) rotates with respect to the stator (19) on air-cushion supports, and the stator (19) slides axially on a further air-cushion support and is insulated with respect to the operating head (11); a signal generator senses the capacitance between the rotor (18) and the stator (19), and generates an electric signal upon the tool (14) on the spindle (13) contacting the upper surface (10) of the board (6); and the signal is used to define a reference dimension relative to the upper surface (10), and to so condition the control unit as to feed the tool (14) to a predetermined depth (K) as of the upper surface (10). <IMAGE> |
