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90 SMT Magazine • June 2016 This classifier analyzes the percentage of component electrode with solder joint accord- ing the IPC-A-610 standards. This percentage value should be higher than 75% for Class III products and 50% for Class I and II products. The parameter Cy corresponds to component size and parameter Py to the pad size on the Y axis. 20 Experimental Results The inspection algorithms were implement- ed using National Instruments' LabVIEW with the Vision Development Module, and Matlab for image processing. The images were acquired under several VT-RNS II AOIs from OMRON, installed on PCB manufacturing lines and the camera resolution, cr, was 20 um/pixel. To validate the proposed approach for sol- der joint reconstruction, some cuts were made over SMD components (Figure 13). Applying the proposed 3D-SJR, the 3D model of the sol- der joint surface illustrated in Figure 14 con- firmed the correlation between the proposed method and the solder joint surface shape. The solder joint reconstruction allows the op- erator to visually check the component state and confirms the failures detected by the AOI system. The 3D-SJR approach was applied over dif- ferent component packages (0402, 0804, and 1206). Figure 15 illustrates an SMD component with a good solder joint. According to the IPC A-610 standard, the solder height at the component electrode must be at least 25% of the electrode height, Cz (19). Considering the component size of the package illustrated in Figure 15 and the camera resolu- Figure 12: Solder joint length [9] . Figure 13: Solder joint profile. Figure 15: Good solder joint sample. Figure 14: 3D-SJR applied over the ceramic capacitor. 3D SOLDER JOINT RECONSTRUCTION ON SMD BASED ON 2D IMAGES