This graph displays results from acoustic emission testing of BGA circuit boards subjected to a spherical bend. The graph shows the top view of the circuit board during testing. The pads that the board rested on during the test, as well as the location of the acoustic emission transducers used as sensors to collect data, are represented as large circles at the appropriate locations. The test causes initial failures at the corners of the circuit board, denoted in the graph as P1, P2, P3 and P4. However the plot is also used to gain a visual understanding of the magnitude, time of occurrence and specific location of the damage.
The symbol size in the plot is relative to the event energy, the symbol color is related to the time the event occurs, and the symbol positions show where these events occur in relation to the circuit board. Electrical open is usually used to determine damage onset but only occurs once a significant amount of damage has occurred – in this case at around 82.1 seconds.
The graph was created using scatter plots. Multiple plots were added to one graph and the symbols were customized according to the data they represented. The symbol size for damage events was linked to a column that contained the information on the event energy on the Symbol tab in Plot Details. The color scale levels were set to reflect different time periods on the Levels tab under Colormap in the Plot Details dialog.
This graph was contributed by Gregory Daspit of the Southern Research Institute, Engineering Research Center in Birmingham Alabama. It is part of a paper; "Acoustic Emission Detection of BGA Components in Spherical Bend", that was presented at the 63rd IEEE ECTC at Las Vegas, NV on May 28-31, 2013