Ball grid arrays are another type of hidden joint device commonly used on PCBs.
3D AXI can detect defects on hidden joints, and can be placed inline, making it feasible for volume manufacturers.
Bingo--you've got a substantial, strong, hidden joint
, which by their nature have limited access, are the main driver for using automated x-ray inspection.
Joints and features hidden under components or leads are made visible; X-ray alone can view the hidden joints
of mounted BGAs, CCGAs, and CSPs.
AXI detects voids, solder quality defects, hidden joints
, and numerous [V.
cannot be inspected with AOI because this technique relies on visible line of sight to the joint.
This includes offline test equipment as well as x-ray systems, which are designed to take a closer look at solder joints and analyze their structure--including hidden joints
(BGA, CSP)--and report on voids inside the joint.