Advanced Ceramic

Advanced Ceramic

CRACK DETECTION in CERAMICS

Resonance Ultrasonic Vibrations (RUV) Technology
  • High accuracy: 91 – 99 percent
  • High throughput: 2-5 seconds/cycle
  • Non destructive
  • In-line & Off-line configuration
Manual RUV system
Manual RUV system

RUV TECHNOLOGY

The Resonance Ultrasonic Vibrations (RUV) technique was developed for off-line and in-line non-destructive crack and stress detection in ceramic materials. The RUV methodology relies on a deviation of the resonance frequency response curve measured on a sample with sub- millimeter length crack compared to identical non-cracked samples.

The RUV technology allows to (1) reject mechanically unstable ceramic objects before they are introduced into further processing, (2) identify objects with cracks and high stress in real-time to avoid in-line breakage, and (3) detect cracked ceramics before they are integrated into the final device to avoid 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.

FREQUENCY CURVE

Through a resonance frequency curve selected from a broad range (20 - 250 kHz), the RUV method enables screen out materials with hidden cracks. A crack introduced into ceramics alters the RUV peak parameters: amplitude, bandwidth and peak position. This is illustrated in Figure 1 for a set of ceramic rings. Specifically, the crack in the ring shows the following features: (1) a frequency shift of the peak position; (2) an increase of the bandwidth, and (3) a reduction of the amplitude. Therefore, the RUV approach is based on a fast measurement and analysis of a specific resonance peak and rejection of the wafer if peak characteristics deviate from the normal non-cracked wafers. Additional RUV feature allows stress inspection caused by package density variation.

Figure 1: Deviations of RUV peak parameters caused by a crack
Figure 1: Deviations of RUV peak parameters caused by a crack

The sensitivity of the 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 this method approaches 99%. RUV system is used in the production of solid oxide fuel cells and metalized ceramic rings.

IN LINE & OFFLINE CONFIGURATIONS

Fully automatic In-line, Off-line and Quality Control RUV Tools are currently available for ceramic products. For technical information and RUV system availability, please contact Ultrasonic Technologies at support@ultrasonictech.com.

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