2-D high precision laser sensor for detecting small defects in PCBs

Through the use of automatic inspection systems is possible to improve the Printed Circuits Board (PCB) manufacturing and reduce the fail rate in this process. In this paper an automatic inspection system for detecting small PCB defects is presented, the system uses a 2-D high precision laser sensor; this kind of laser sensor allows getting high precision measurements with an error of units of micrometers. The sensor is able to detect Surface-Mount Devices (SMD) onto PCB in order to perform a defect-detection process. The system uses an open, modular and scalable architecture for controlling a robotic motion in two axes, also a graphic application coded in Java for data processing and unify all the components is developed. Finally a judgment algorithm for defect-detection evaluation using binary matrices is added to the system. The aim of this system is that it can detect small PCB defects using a 2-D laser sensor and that is possible to implement it in a production line. Design, tests and results gotten are shown.