Crack Detection in Ceramic Plates Using Resonance Ultrasonic Vibrations (RUV) Technology

The Resonance Ultrasonic Vibrations (RUV) technique was developed for off-line and in-line non-destructive detection of cracks in ceramic parts such as plates for fuel cells, metallized rings and dental discs. The RUV methodology relies on a deviation of the resonance curve parameters measured on a part with peripheral or bulk millimeter-length crack and on identical non-cracked part.

A ceramic is a widespread material and a noticeable contributor to the overall cost of modern electronics. To reduce the cost per Watt of fuel cell module, individual cells are made thinner with thickness down to a few hundred microns. Active cell area has also been increased to reduce overall production costs. These technological trends make ceramic handling in production more challenging and reduce the yield of fuel cell lines due to increased probability of cell breakage. In-line breakage also reduces equipment throughput as a result of downtime.

The RUV technology allows: (1) rejection of mechanically unstable bare ceramic plates before they are introduced into further processing, (2) identification of plates with mechanical flaws (such as cracks) during production to avoid their in-line breakage and yield reduction, (3) detection of cracked fuel cells before they will be combined into modules to avoid efficiency reduction and product return from the field. RUV system also serves as a process control tool to increase yield by eliminating production flaws caused by mechanical defects.

The sensitivity of the RUV system, which refers to the length of the cracks, is adjustable to the needs of the user. The rejecting method is based on a statistical approach. In case studies the accuracy of RUV method was between 91 - 95%. That means that after RUV inspection the breakage caused by cracked plates or cells is reduced by at least a factor of 10. RUV tools are designed to satisfy various customer’s needs and demands. Our application group will perform an on-site inspection of your products and provide practical recommendations.

In-line and off-line RUV systems are readily available and can be customized to address specific features. Please Contact Ultrasonic Technologies for more information or to discuss your particular needs.