Maalouf, K., Stull, D., and Nicholas, K., "Ultrasound for Crimp Inspection," SAE Int. J. Engines 9(3):1393-1397, 2016, doi:10.4271/2016-01-0104.
In copper wire, real time crimp monitoring has traditionally been based on force measurement during the crimp cycle. The force attributed to molding the copper wire into the terminal is a significant portion of the total force needed to form the crimp. Therefore, any wire deviation from the norm is translated into a force pattern aberration that can be detected using basic signal pattern analysis.As the mobility industry is contemplating replacing copper with aluminum wire, in order to save on weight and material cost, the traditional force monitoring becomes ineffective in detecting wire faults in the crimp. The reason is that aluminum is softer than copper, and most of the force exerted during the crimp cycle is consumed by forming the copper terminal itself. The small force deviation due to an aluminum wire fault becomes much more difficult to detect. Therefore, a new technique is needed to monitor crimped aluminum wires. In this paper, we investigate the feasibility of using ultrasound technology to monitor a crimp press cycle in order to separate a normal from a faulty crimp.