Microprocessor controlled detection and drilling of PCB holes utilizing an X-Y stage scanner

Abstract

The purpose of the thesis is to design and realise a system to detect and simulate the drilling of drilling-hole positions in printed circuit board masks making use of a stepper motor driven mechanical moving stage scanner under the control of microprocessor. Determination of the print outline and the effective frame length, detection of the dots at proper drilling-hole positions, scanning of the dot mask in a meander pattern, generation of switching sequence of the unipolar stepper motors are under the control of software and achieved by interfacing the stage scanner, drive circuitry of the steppers and the detection system to a Z~80 microprocessor card. Since all the control actions are performed by the microprocessor, the prototype can be considered as an intelligent system. The drilling part of the software minimizes the drilling process time making use of path algorithm.