PCB Defect-Detection System Using a 2-D High Precision Laser Sensor

Abstract

In the Printed Circuit Boards (PCB) manufacturing is common to use the Surface-Mount Technology (SMT) and Surface-Mount Devices (SMD) for constructing circuits directly onto the surface of PCBs. SMT allows increase the density of components inside a PCB, but the problem for detecting defects in collocation and soldering of small components is faced. In this paper an automatic inspection system for detecting small defects on PCBs is described. The system uses a high precision laser sensor, this sensor uses a segment of laser beams in order to get a profile over the PCB surface instead of a single measure point. An open, modular and scalable architecture for controlling a robotic motion in two axes is implemented, also a graphic interface coded in java for data processing and unify all the inspection system components is developed. Finally a judgement algorithm for defect-detection evaluation is added to the system. The main goal 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.