The system uses a pulsed, high-frequency sound impulse that is transmitted and received by a transducer mounted on an x-y gantry. The return signal or echos are gated to produce a layer-by-layer image. Images can be displayed in 2 or 3 dimensions with the addition of false colour to aid interpretation.

This acoustic system is very effective in the detection of cracks or delamination in plastic packages. For assembled PCBs the imaging can be performed in-situ ensuring that false failure data is not created by the device removal process.

RoHS compliant processes that require higher reflow temperatures have increased the possibility of introducing device defects during the assembly process. Equally some rework operations such as device re-balling carry a significantly increased risk due to multiple temperature processing cycles. Using acoustic imaging it is possible to screen suspect devices before further rework is undertaken. This can be carried out with the device in-situ on a PCB or as loose devices on a tray.