A GMR-ECT based Embedded Solution for Applications on PCB Inspections

Real-time non-destructive testing and evaluation (NDT/E) of conducting materials using eddy current techniques (ECTs) has gained significance in the last few years. This paper proposes a real-time application of ECT–NDT system exploiting giant magneto-resistive (GMR) sensors for inspection of printed circuit boards (PCBs). Probe design aims to crack inspection over flat surface, especially suitable for micro-defect detection on high density bare PCB. We propose a system based on a GMR sensor able to detect the magnetic field resulting from the interaction between a planar coil exciter and PCBs. The EC signals, detected by the GMR sensor, have been acquired by a high speed analog-to-digital (A/D) converter, for a subsequent application of signal processing based on digital techniques. The achieved results have highlighted the efficient design of the system. The advantages of the proposed models and some possible improvements of the system are also discussed.