contact with the surface for more than a second, the
MX-3
will display the smallest meas-
urement it found.
When the
MX-3
is not in calibration mode, press the
UP
arrow key to turn SCAN Mode
on and off. A brief message will appear in the display confirming the operation.
While scanning, the display will show a moving series of dashes instead of a thickness
value. When the transducer is removed from the material being scanned, the
MX-3
will (af-
ter brief pause) display the smallest measurement it found.
Transducer Selection
The
MX-3
is inherently capable of performing measurements on a wide range of
materials, from various metals to glass and plastics. Different types of material, however,
will require the use of different transducers. Choosing the correct transducer for a job is
critical to being able to easily perform accurate and reliable measurements. The following
paragraphs highlight the important properties of transducers, which should be considered
when selecting a transducer for a specific job.
Generally speaking, the best transducer for a job is one that sends sufficient ultrasonic en-
ergy into the material being measured such that a strong, stable echo is received by the
MX-3
. Several factors affect the strength of ultrasound as it travels. These are outlined be-
low:
Initial Signal Strength
The stronger a signal is to begin with, the stronger its return echo will be. Initial signal
strength is largely a factor of the size of the ultrasound emitter in the transducer. A large
emitting area will send more energy into the material being measured than a small emitting
area. Thus, a so-called 12.7 mm
∅
transducer will emit a stronger signal than a 6.35 mm
∅
transducer
Absorption And Scattering
As ultrasound travels through any material, it is partly absorbed. If the material through
which it travels has any grain structure, the sound waves will also experience scattering.
Both of these effects reduce the strength of the waves, and thus, the
MX-3
‘s ability to de-
tect the returning echo.
Higher frequency ultrasound is absorbed and scattered more than ultra-sound of a lower
frequency. While it may seem that using a lower frequency transducer might be better in
every distance, low frequencies are less directional than high frequencies.
Thus, a higher frequency transducer would be a better choice for detecting the exact loca-
tion of small pits or flaws in the material being measured.
Geometry Of The Transducer
The physical constraints of the measuring environment sometimes determine a transdu-
cer’s suitability for a given job. Some transducers may simply be too large to be used in
tightly confined areas. Also, the surface area available for contacting with the transducer
may be limited, requiring the use of a transducer with a small wearface. Measuring on a
curved surface, such as an engine cylinder wall, may require the use of a transducer with
a matching curved wearface.
Temperature Of The Material
When it is necessary to measure on surfaces that are exceedingly hot, high temperature
transducers must be used. These transducers are built using special materials and techni-
ques that allow them to withstand high temperatures without damage.
Additionally, care must be taken when performing a „Probe Zero“ or „Calibration to a
Known Thickness“ with a high temperature transducer.
Operation
MX-3
Manual
Rev:00
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