Atec Panametrics-Olympus-Omniscan-MX - Manual (Page 6)

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3
4
2
1
Transmitting
delays
Receiving delays
and sum
Probe elements
Pulses
Incident wave front
Reflected wave front
Trigger
Flaw
Flaw
Echo signals
Emitting
Acquisition unit
Receiving
Phased array unit
The use of phased array probes enables one-line scanning
and eliminates one axis of a two-axis scan.
Scanning direction
Active group
128 1
16
11 angles
Wedge and
phased array
probe
Multiple-angle inspection with one multielement probe. Greater flexibility for the inspection of complex geometry.
High-speed scans with no moving parts.
Compared to a wide, single-element transducer, phased
array technology offers a much higher sensitivity due to the
use of a small focused beam.
To generate a beam, the various probe elements are pulsed at slightly different times. By precisely controlling the delays between
the probe elements, beams of various angles, focal distances, and focal spot sizes can be produced. The echo from the desired
focal point hits the various transducer elements with a computable time shift. The signals received at each transducer element
are time-shifted before being summed together.
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Phased Array Probes
Olympus standard phased array probes are
divided into three categories:
• Angle beam probes with external
wedges (1) (2)
• Angle beam probes with integrated
wedge (3)
• Immersion probes (4)
Numerous accessories, such as encoders (5)
are also available.
Phased Array Technology
Phased array technology enables the
generation of an ultrasonic beam where
parameters such as angle, focal dis-
tance, and focal point size are controlled
through software. Furthermore, this beam
can be multiplexed over a large array.
These capabilities open a series of new
possibilities. For instance, it is possible to
quickly vary the angle of the beam to scan
a part without moving the probe itself.
Phased arrays also allow replacing mul-
tiple probes and mechanical components.
Inspecting a part with a variable-angle
beam also maximizes detection regardless
of the defect orientation, while optimizing
signal-to-noise ratio.
Benefits of Phased Arrays
Phased array technology offers the follow-
ing benefits:
• Software control of beam angle, focal
distance, and spot size
• Multiple-angle inspection with a
single, small, electronically-controlled
multielement probe
• Greater flexibility for the inspection of
complex geometry
• High-speed scans with no moving
parts
Phased Array Inspection