A-Scan is a fundamental ultrasonic display mode that provides a real-time visualization of the raw ultrasonic signal, or "waveform." While B-Scan shows a profile of the material, A-Scan allows the operator to see the actual sound energy as it travels through the part, making it the essential tool for troubleshooting and precise calibration.
How it Works
The Waveform Pulse: The gauge displays a graph where the horizontal axis represents time (or distance) and the vertical axis represents the signal strength (amplitude). Each "peak" on the screen represents the sound reflecting off a surface.
Identifying the "Back Wall": The first major spike on the left usually represents the initial pulse at the surface, while a second distinct spike further to the right represents the "back wall" echo. The distance between these two spikes is how the gauge calculates thickness.
Signal Interpretation: By viewing the waveform, an operator can distinguish between a true thickness reading and "noise" or false echoes caused by internal grain structures, small inclusions, or heavy pitting that might confuse a standard digital display.