In acoustic resonance inspection the resonances of a part are measured to determine the structural characteristics of that part in a single test. The whole part is examined for both external and internal structural flaws.

The resonances of a part are determined by the mass, structural stiffness, and structural damping of the part. Flaws that are structurally significant, whether arising from material issues (hardness, grain structure, inclusions, residual stress) or from process related issues (cracks, voids, missing material, dimensional issues), will affect one or more of mass, stiffness or damping and this will cause detectable shifts in the resonances of the part.

Once measured, the resonances of the subject part are compared to those from a control set of normal parts and the subject part is determined to be normal (OK) or not normal (NOK).

Detects resonant frequency shifts resulting from changes in mass, stiffness or damping of a part. Defects such as cracks, voids, chips, brazing problems, nodularity, porosity, variations in hardness, missed manufacturing processes and delamination can be detected.
Applications include powder metal parts, ductile iron parts, brazed assemblies, forgings, stampings and ceramic parts.

• Whole part test for internal and external flaws
• Fast – Three seconds per part, typical
• No part preparation required
• Objective pass/fail result
• No consumables expenses
• Easily automated
• Permanent record capability
• Easily finds first n number of natural frequencies for NVH applications
• Best for high volume quality inspection
• Designed to be on the plant floor

• Not diagnostic - does not indicate where flaw is, just there is one
• Materials that resonate only - metal, composites and ceramic parts
• Large parts (> 60lbs) difficult to test
• Significant lot to lot variations can mask defect detection