A computer-controlled drilling machine for printed circuit boards (CCDM for PCBs)

• Main Authors: Jalbuena, Lizette H., Marquez, Jose Maria M., Romey, Ronella G., Valerio, Charlie R.
• Format: text
• Language: English
• Published: Animo Repository 1988
• Subjects: Programmable controllers; Printed circuits; Drilling and boring machinery > Numerical control; Microcomputers > Programmable peripheral interfaces
• Online Access: https://animorepository.dlsu.edu.ph/etd_bachelors/16423
• Institution: De La Salle University

The objective of this study is to automate a drilling machine for Printed Circuit Boards (PCBs) by interfacing it to an IBM PC XT microcomputer using the concepts of Numerical Control (No). Numerical Control is control of a machine tool by means of a prepared program. Using NC concepts, tedious manual operations like marking onboard each hole that has to be drilled, and repeating this for all the boards to be drilled, is eliminated. The user can avail of the system's software facilities to design his artwork and leave the actual drilling to the computer. As a result, speed and accuracy are improved. The artwork for the PCB is first designed on paper to make it easier for the user to transcribe it later onscreen through the software CLEVERwork. CLEVERwork then provides the user with functions in edit, delete, view and print-out-PCB design before the actual drilling takes place. The PCB on which the artwork is to be drilled is clamped on the X-Y plane of the drilling machine. CLEVERwork then translates the relative positions of the holes drawn onscreen into electronic signals which drive the stepper motors controlling the M, Y, and Z axies. These signals are generated through the interface card which serves as a link between the drilling machine and the computer. Aside from CLEVERwork, another of the drilling machine's features include microswitches acting as sensors to detect the presence of a PCB on the plane, the application of power to the machine, the initial positions of the x-y plates and vertical drill and the presence of a hole drilled. A problem is that the stepper motors controlling the xy plates stall in place at fast speeds and at certain points of the XY plane due to the latter's rustiness, leading to errors in positioning during drilling. By controlling the stepper motors to move at an acceptable, though not fastest speed, accuracy is not sacrificed.