Selective Solder Nozzle Geometry and Thermal Preheat Window Boundaries
Optimal selective soldering requires balancing nozzle orifice dimensions with precise top-side preheat windows to achieve Class 3 vertical barrel fill.
X Ray Microsection Inspection
Virtual Sectioning
Non-destructive evaluation of internal solder joints and printed circuit board layers is performed using computerized tomography to generate high-resolution cross-sectional images without destroying the assembly. Through x ray microsection inspection, quality control engineers obtain detailed visual slices of the internal structure of area array packages such as ball grid arrays. This technique provides a three-dimensional view of hidden solder joints, internal vias, and copper traces.
By using multi-angle x-ray beams, the imaging system reconstructs the physical layers of the board to reveal internal features that are invisible to the naked eye. These reconstructed slices allow engineers to measure the volume of solder and the shape of the joint fillet precisely across several horizontal planes.
Defect Detection
Locating microvoids and cracks within solder balls requires a high degree of spatial resolution that standard visual inspection cannot achieve. When performing x ray microsection inspection, the software identifies variations in material density to isolate voids, solder bridges, and head-in-pillow defects. This method is especially critical for verifying the integrity of bottom-terminated components where the solder joints are completely concealed by the component body.
It allows manufacturers to detect process drift in the reflow oven early before high volumes of defective boards are produced.
Structural Testing
Physical microsectioning is a destructive process that requires potting and polishing the sample, which ruins the board. In contrast, x ray microsection inspection allows the same board to continue through the production cycle or be shipped to the customer if it passes inspection. Quality standards use these digital images to audit the assembly process and verify compliance with IPC specifications.
This testing method reduces scrap costs while providing equivalent dimensional feedback on via fill, solder joint height, and voiding percentages.