Abstract
Quasar Resonant Inspection (QRI) vibrates a part and measures its resonant frequencies to detect the presence of defects. Parts made by a process that is in control have a similar pattern of resonances determined by the parts dimensions and material properties. QRI identifies patterns that discriminate between acceptable and unacceptable variations in properties and dimensions. An unacceptable pattern indicates the presence of a defect and the QRI computer rejects the part.
The fact that QRI is based on measurable physical properties means that its results are quantifiable and repeatable. Parts are rejected because of their structural properties, with no operator judgment about the severity of a defect. The manufacturer can set the level of defectiveness for rejection and be confident that all of the truly defective parts are rejected and that no parts are rejected because of superficial indications.
The key to QRI is the Sorting Module, which is the set of patterns that describe the characteristics of an acceptable part to the QRI computer. First, resonant frequencies are measured for a learning set of parts (both good and defective). Then, the results are input to GALILEO, Quasars pattern recognition program, which generates the Sorting Module and translates it into instructions for the
QRI System. In production, each part is vibrated and the Sorting Module accepts or rejects it based on its deviation from the accepted standard for stiffness and/or dimensions. When design or process changes occur, GALILEOs Maintenance mode is used to update the Sorting Module.