Minicomputer controlled automatic PCB drilling system - scans reference plan marked with accurately printed dots using optical sensor and calculates and drives drilling head

摘要

The system is intended to drill component lead and other holes automatically by scanning a reference diagram (1) and taking coordinates from it. The drilling plan has a number of circular dots accurately printed on it whose position and dia. correspond to the location and diameter of the hole to be drilled. An optical sensor (60), moving under the action of a stepper motor along orthogonal slide bars (30,42), detects the edge of a dot and, under the control of a dedicated minicomputer, measures the distance to the point on the opposite of the chord of the circular dot. By back-tracking and scanning a line at right angles to the first, the sensor inputs information to the computer which establishes accurately the centre position and size of the hole. The whole reference diagram is scanned in sweep directions parallel to the coordinate axes and the computer memory stores all information for a drilling operation.