Abstract: In a method of injecting an electrically conductive epoxy into blind vias during drilling or shortly thereafter in order to avoid oxidation of the copper or other metal of the imbedded layer, a machine tool is provided with at least one controllable spindle and at least one injection device. Alternatively, two machine tools, one with at least one controllable spindle and one with at least one injection device, may be provided. A printed circuit board mounted on the machine tool table for drilling is registered in the usual way for the particular machine tool. The machine tool part program then drills a particular pattern for the circuit board for mounting of circuit board components. All of the blind vias as well as through hole vias are drilled at one time by the machine tool by the tools mounted in the spindle or by laser drilling systems, but may also be drilled and filled in any sequence.

Abstract: In a system which interrupts the infeed signal generated by a CNC machine drive signals are applied to at least an RPM Control Electronics Module to drive the rotation of a cutting tool and the infeed drive motor electronics. A solid state relay intercepts the infeed signal and is driven into an on off state by a Variable Frequency Generator. This causes the solid state relay to enter the on off state in response to the input frequency and interrupts the infeed signal applied to the infeed motor electronics in synchronization with the frequency generated. The frequency is user selectable and the frequency used to eliminate or minimize chip formation is dependant upon the material being drilled, the infeed rate, the RPM of the tool, and the diameter and point geometry of the tool so adjustment by the machine operator is required. This permits the user to vary the specific frequency to select a frequency which is suitable for elimination of spirals in a given set of circumstances.