Category: Characterization > Sampling & Analysis Equipments > Analysis Equipment
Reference # : Model No :
Zetec, Inc. provides ultrasound technology equipment and software. Ulstrasound inspections can be performed by manually moving a transducer over a component or by connecting it to an encoded scanning mechanism. Phased array (PA) technology allows the control of the acoustic characteristics (refracted angle, focal distance, aperture, etc.) of ultrasonic beams through software. A phased array probe consists of a series of piezo-composite elements, which can be excited independently one from the others. By precisely controlling the time delays between the excitation of the individual elements, ultrasonic beams of various angles, focal distances and aperture can be transmitted in the inspected specimen. The returning echo from a reflector is detected by each elements of the PA probe at a slightly different time. The individual echo signals are then time-shifted before being summed up. The result of this process is an a-scan that emphasizes the response from the desired focal point.
Ultrasound testing (UT) is a very useful and versatile nondestructive testing method that allows for a full volumetric examination of the component. It uses high-frequency sound waves that are transmitted through a test piece and/or reflected by discontinuities inside it. This can be used for inspections requiring a single channel or multi-channel configurations.
The advantages of phased array are as follows
•Multiple refracted angles and focal distances can be generated simultaneously by a single search unit;
•Ultrasonic beams can be electronically moved over the length of the PA probe, without any mechanical movement;
•By using multiple ultrasonic beams, the probability of detection can be increased;
•Automated or semi-automated inspection methods can be implemented more efficiently.
The operator must be aware of the limitations of the beam formed by the phased-array system. This includes probe design, instrument timing limits for phasing, plane of required focusing, near-zone extents of the beam (with provision for wedge delay effects), beam size required to improve signal-to-noise ratio and resolution and required resolution and the method of assessing that resolution.