Geometric Calibration Targets for Surface Mount X-Ray Inspection
Geometric calibration targets establish spatial scale and correct optical distortion, guaranteeing valid void and dimensional measurements in SMT X-ray inspection.
Tungsten Carbide Target
Anode Source
High-power X-ray tubes utilize metal targets on their anodes to generate the radiation needed for industrial non-destructive testing. A tungsten carbide target consists of a tungsten and carbon compound that provides high thermal conductivity and a high melting point. This component is positioned in the path of the focused electron beam to generate X-rays via bremsstrahlung radiation.
The use of this material allows the tube to operate at higher power levels without damaging the target surface.
Durability Evaluation
Target wear is a major factor in the lifespan and performance of high-resolution micro-focus tubes. In systems that utilize a tungsten carbide target, the high hardness of the material reduces the rate of surface degradation caused by the high-energy electron beam. This durability ensures that the focal spot remains small and stable over hundreds of hours of operation.
A stable focal spot is necessary for maintaining the high spatial resolution needed to inspect sub-micron solder defects.
Xray Generation
X-ray emission efficiency depends on the atomic number of the target material and the applied tube voltage. For a tungsten carbide target, the high atomic number of tungsten ensures a high yield of X-ray photons, which improves the image contrast. This increased contrast is critical for automated solder joint inspection where the software must distinguish between different solder thicknesses and voiding levels.
System software adjusts the electron beam focus to maintain a consistent spot size across the entire power range. This control allows the system to generate high-quality images of multi-layer boards and high-density components. By maintaining this image quality, the system avoids false-reject errors that can occur when low-contrast images fail to resolve the borders of internal solder voids.