To provide a method and device which can establish a control of the cutting depth in a multi-layer base board with high reliability in a very simple structure.
A cutting depth control device is equipped with an operational head 11 movable relative to a plate to be processed 6 under control made by a control unit, and the head 11 is furnished with a plate holding device 21 and a motor 17 for driving the spindle 13. The rotor of this motor 17 rotates relative to a stator 19 on an air cushion support, and the stator 19 slides in the axial direction on another air cushion support and is isolated from the operational head 11. A signal generator senses the capacitance between the rotor 18 and stator 19 and emits a signal when the tool 14 on the spindle 13 contacts with a conductive layer provided on the oversurface 10 of the plate concerned 6. The signal conditions the control unit so that it defines the reference dimension of cutting depth to the oversurface 10 and feeds the tool 14 to the prescribed depth according to the reference.
JPH07205096 | TAPPING CUTTER |
JP3333194 | [Title of Invention] A device for driving a rotary tool. |