X-Ray Inspection for Electronics from China
1 resources tagged with "X Ray"
X-ray inspection (AXI) is the only way to see solder joints hidden under BGA and QFN packages, and for PCBAs from China it is the check that catches voids, bridging, and head-in-pillow defects you cannot inspect optically. BGA void analysis follows IPC-7095, which sets the void percentage limits per ball. The practical choice is 2D AXI for void counting versus 3D AXI for layer-by-layer joint reconstruction on dense boards.
When you require X-ray, specify the standard (IPC-7095C for BGA voids), the sampling level (AQL or 100% on critical assemblies), and whether 2D or 3D — leaving it vague means the factory may run a token sample that misses systematic reflow problems.
Wiki (1)
FAQ
When do I actually need X-ray inspection?
Whenever you have BGA, QFN, or bottom-terminated packages whose joints are hidden under the part. Optical inspection cannot see them, so X-ray is the only way to confirm solder quality and void levels.
2D or 3D X-ray — which should I ask for?
2D AXI is enough for BGA void percentage and gross defects on simpler boards. 3D AXI reconstructs joints layer by layer and is worth the extra cost on dense, double-sided, or high-reliability assemblies.
What void limit should I specify for BGAs?
Reference IPC-7095 and state the acceptable void percentage per ball for your class. Typical limits sit around 25% per ball, but high-reliability work tightens this, so name the standard rather than relying on the factory default.
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