Ultrasonic Thickness Gauge TT100

Ultrasonic Thickness Gauge TT100
Ultrasonic Thickness Gauge TT100
Instruction Manual
TIME Group Inc.
Beijing TIME High Technology Ltd.
CONTENTS
1. GENERAL DESCRIPTION.................................................................................................... 2
2. PERFORMANCE PARAMETERS........................................................................................ 6
3. MAIN FUNCTIONS ................................................................................................................ 7
4. MEASURING STEPS .............................................................................................................. 8
5. MEMORY OF THICKNESS VALUE ................................................................................. 15
6. MAINTENANCE ................................................................................................................... 17
7. OPERATION.......................................................................................................................... 19
8. PREVENTION OF MEASURING ERRORS...................................................................... 26
9. NON-WARRANTY PARTS.................................................................................................. 29
1
1. General description
1.1 Scope of applications
The handheld microprocessor-controlled thickness gauge is designed for measuring the
thickness of metals, and non-metallic materials e.g. aluminum, titanium, plastics, ceramics,
glass and any other good ultrasonic wave-conductor as far as it has two parallel surfaces on
the top and bottom.
The TT100 can be used in industrial applications to perform precise measurements on
various kinds of new materials, parts and components, and it can also be used to monitor
various kinds of pipes and pressure vessels for the decrease of their thickness due to
corrosion and/or erosion.
1.2 Basic working principle
The principle of ultrasonic wave in the thickness measurement is similar to that of optical
wave. The ultrasonic wave pulses transmitted by the probe will be reflected back, while they
reach the interfaces. The thickness of the object is determined by precisely measuring the
time the ultrasonic wave travels in the object.
2
3
1.3 Basic configuration and each part description of the tester
1.3.1 Basic configuration:
Main processor: 1 piece
Transducer: 2 piece
Couplant: 1 bottle
1.3.3 The name of each part of the testing meter (see figure below):
LCD screen display:
BATT : low voltage indication
凸: coupling indication for satisfactory acoustic coupling between probe and test piece
m/s : measurement unit of sound velocity
4
mm : measurement unit of thickness
Keyboard:
ON
: power
ZERO: transducer zero procedure
VEL : sound velocity value / 5 velocity are stored
▲-▼:
adjustment
keys
for
sound
velocity,
thickness, 10 memory units for thickness storage
5
2. Performance parameters
Display type:
Display resolution:
Measuring range:
Lower limit for steel pipes:
Measurement accuracy:
Sound velocity range:
Coupling check:
Memory:
Range of operating temperature:
Surface temperature of workpiece:
Working frequency
Update rate:
Power supply:
Battery life:
Dimensions:
Weight:
4-digit LCD
0.1 mm
1.2mm – 225.0mm with 5MHz transducer
Ф20 mm × 3.0 mm
±0.1mm
1000 – 9999 m/s
satisfactory / no probe coupling
10 thickness readings
0℃~40℃
-10ºC~60ºC
5 MHz
4 Hz
2 AA batteries 1.5V
250 hours
126mm×68mm×23mm
250g including batteries
6
3. Main functions
1)
Automatic transducer zero adjustment: automatically correct the system errors
2)
Automatic non-linear compensation: within the full range, computer software is used
to correct the non-linear errors of transducer with the purpose of improving the accuracy
3)
Keys ▲-▼ are used for fast adjustment of sound velocity and thickness as well as fast
checking the thickness memory unit
4)
Calibration of known sound velocity
5)
Calibration of a known thickness (the sound velocity can be directly determined
according to a known thickness, avoiding the trouble of looking into table.)
6)
Ten different thickness values can be stored and kept after switch-off
7)
Coupling indication: the stability can tell if the coupling is normal
8)
Sound velocity of five different materials can be stored
9)
Indication at low voltage
10) Automatic switch off
7
11) Oil proof keyboard with longer service life
4. Measuring steps
4.1 Preparations for measurement
z Connect the transducer plug to the socket on top of the unit.
z Turn on the gauge.
As it is shown in the figures below, after the full screen display for a few seconds, the
screen will display the sound velocity used last time. The measurement can start now, but
read other paragraphs first.
8
Full screen display
Sound velocity
Note: The surface of the probe is made of propylene resin and is very sensitive to heavy
scratches on rough surfaces, so in application, push the probe gently on the surface.
Automatic turning off
If no operation performed within two minutes, the unit will be turned off automatically.
4.2 The adjustment of sound velocity
9
If the screen currently is displaying the thickness value, then press the VEL-key to enter
into sound velocity state. The content of the current memory unit of sound velocity will be
displayed on the screen. Each time the VEL-key is pressed the sound velocity memory unit
will change. Five different sound velocity values will be displayed in turn.
If the current displayed sound velocity is desired to be changed, the keys ▲-▼ can be used
to adjust it to the desired value. This value will be stored automatically as one out of five
stored velocities.
4.3 Calibration
Each time the transducer or battery is changed, calibration should be performed. This step
is rather critical to secure the measuring accuracy. If necessary, calibration can be repeated
several times. Take following steps:
z
z
Put a little coupling agent on the steel master testing block on the unit, which has a
thickness of 4.0mm.
Adjust the sound velocity to 5900 m/s (steel) using the VEL-key and the keys
▲-▼
10
z
Press the ZERO-key and enter into the state of calibration and on the screen displaying:
z
Coupling the transducer with test block. At this time the bar lines displayed on the
screen will disappear one after the other until the screen displays 4.0mm. That means
the calibration is over:
11
4.4 Calibration to a known velocity: thickness measurement
z
z
z
z
Lay the coupling agent on the place to be measured.
Adjust the sound velocity according to the material (refer to table in paragraph 7). (If it
is not clear what the right sound velocity should be, for example when the material is
unknown or readings are not correct at a certain velocity, please refer to paragraph 4.5)
Couple the transducer with the workpiece to be measured.
Start the measurement. On the screen it will display the thickness of the material to be
measured, for example:
12
Note: When the transducer is coupled with the workpiece to be measured, the coupling
indication sign will be displayed on the left side on the screen. If the coupling indication
flicks or does not appear, it shows that the coupling is not well done. Take the transducer
away, the thickness value will remain and coupling indication will disappear.
4.5 Calibration of a known thickness: sound velocity measurement
If it is desired to measure the sound velocity of a certain material, a testing block with a
known thickness must be used, operation is as the follows:
z Measure the test piece thickness with a caliper or micrometer
13
z
Couple the transducer with the test piece of known thickness until a (wrong) thickness
value is displayed:
z
Remove the transducer.
Adjust the displayed thickness value to the actual known thickness of the testing block
by keys ▲-▼, for example 25.0 mm:
z
16.7
> keys ▲-▼ >
25.0
mm
z
mm
Now press the VEL-key. The correct sound velocity for this material will be
displayed, and at the same time this sound velocity will be stored in the current
sound velocity memory unit:
14
25.0
> VEL-key >
mm
z
6368
m/s
Start new thickness measurements on the same material with this velocity.
5. Memory of thickness value
5.1 Thickness memory state
z
z
z
z
Set the right sound velocity for a new measurement (see chapter 4).
Press and hold VEL-key and then press the ZERO-key to enter into the thickness
memory state.
The display will show a memory unit of a certain thickness: Unit 1 up to Unit 9.
Use the upper and down keys ▲-▼ to look for the required unit:
U1 > U2 > U3 > …… > U9
z
While measuring the thickness, the value measured will be stored in the chosen unit
automatically. Each time a new value is measured, the old value in this unit will be
automatically replaced.
15
U1
z
>>
3.0
mm
Press the VEL-key once more to leave the thickness memory state.
5.2 Reviewing the thickness memory units
z
z
z
Press and hold the VEL-key and then press the ZERO-key to enter the thickness
memory
The display will show a memory unit of a certain thickness: Unit 1 up to Unit 9.
Use the upper and down keys ▲-▼ to look for the required unit:
U1 > U2 > U3 > …… > U9
z
Again press and hold the VEL-key and press ZERO-key to show the stored reading:
U1
> VEL + ZERO >
3.0
mm
z
Press the VEL-key to leave the thickness memory state.
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6. Maintenance
6.1 Low voltage indication
If BATT is displayed on the screen, it shows that the battery voltage is running low and the
batteries should be replaced in time before the unit can be used again.
Battery replacement:
A. Wait until the unit turns off automatically.
B. Open the battery compartment (press down the compartment cover and slide it out).
C. Remove the used batteries and put in new batteries. Note the polarity of the battery.
6.2 Precautions
z The surface of the transducer is made of propylene resin and is very sensitive to heavy
scratches on rough surfaces, so in application, push the probe gently on the surface.
z The temperature of the workpiece surface should not exceed 60ºC, otherwise the
transducer will be damaged.
z Dust, iron chips, and carbon particles will cause trouble; keep the gauge clean all the
time.
z Grease, oil and dust will make the cable of the transducer aged and cracked, therefore,
17
z
z
z
after the use, the cable should be cleaned of dust and dirt.
If the gauge is not to be used for a long time, remove the batteries.
Strictly avoid any collision or damp environment, etc.
Automatic switch-off of the machine
In addition to two AA batteries, there is a lithium cell inside the thickness gauge to
provide uninterrupted power source for the ROM. If the two AA batteries are taken out
before the thickness gauge has not automatically switched off, the instrument will be
forced to use the lithium cell and once the cell is exhausted and replaced, all the data
stored in the ROM will be lost. So the batteries can be taken out only after the instrument
switches off automatically.
z
Cleaning of test blocks.
As the correction of the instrument by using the test block provided needs coupling
agents, it is necessary to take measures against rusting. After use, the test blocks must be
cleaned. When the temperature is high, caution must be taken not to stain it with sweat.
When not used for a long time, the test block should be coated with a thin layer of grease
to prevent rusting.
z
Cleaning of the shell of the instrument
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The shell of the instrument should be cleaned with a little amount of clean water instead
of alcohol or dilution liquid which are corrosive to the shell, especially the window.
7. Operation
7.1 Scope of application
Metals, plastics, porcelain, glass and other good conductor of ultrasonic waves, as long as
there are two parallel planes, such as aluminum, copper, gold, resin, water and glycerin.
The instrument can not be used to measure the thickness of cast iron because of too big
grain inside.
7.2 Requirements for work pieces
7.2.1 Requirements for the area of work piece
All work pieces with area larger or equal to the area of the probe can be measured. But for
long slender pieces, errors may occur when it is measured in the axial direction or the side
of the work piece is not vertical to the testing surface as the testing surface is too small.
7.2.2 Requirements for curved surface
When the test piece has curved surface (such as the side wall of a boiler or tubular
materials), the radius of the curvature should be R≥10 and the wall thickness ≥3mm. But
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this is applicable to steel only. We have not worked out accurate requirements for other
materials due to our inexperience. Users may gain experience in the process of use and we
shall be very grateful is you can tell your experience to us.
7.2.3 Requirements for roughness.
The requirements for roughness are very lenient. In usual circumstances, accurate
measurement can be attained of the probes we supply are used. But if the roughness is too
big due to serious rust other reasons, errors may occur. When this occurs, measures should
be taken to lessen the roughness or select the 2.5mm probe, which can be ordered from
our company.
7.2.4 Requirements for working temperature
The thickness of materials and the transmission speed of ultrasonic waves are all affected
by changes in temperature. But for measurement that requires only general accuracy, the
effect of temperature can be ignored.
However, the working surface temperature should not be higher than 60ºC out of the
consideration of protecting the probe and ensuring accuracy as the probes are made of
propylene resin.
20
7.3 Working environment
Working temperature: 0~40ºC;
Relative humidity: 90%;
Temperature of work piece:<60ºC;
No violent vibration or corrosive media;
Strictly avoiding colliding and humidity.
7.4 Measuring technology.
7.4.1 Cleaning the surface.
Before measurement, it is necessary to clean the dust, dirt or rusty matters and coatings of
the surface of the test object.
7.4.2 Lessening the roughness.
Too rough surface may cause errors or no reading. Before measurement starts, measures
should be taken to keep the test surface smooth by way of grinding, polishing and filing.
High viscosity coupling agent may also used.
7.4.3 Roughly machined surface.
The regular fine furrows of roughly machined surface (such as lathing or planer) may also
21
cause errors. The remedy is similar to 2.5.2. Better result can also be achieved by
adjusting the intersectional angle between the probe crosstalk isolating board (the thin
metal layer on the bottom center of the probe) and the fine furrows of test materials
(orthogonal or parallel).
7.4.4 Special surface.
It is essential to select the right intersectional angle between the probe crosstalk isolating
board and the axial line of the test materials in measuring materials with spherical surface,
such as tubes or barrels. Simply speaking, make the probe coupled with test materials and
the probe crosstalk isolating board and the axial line of the test materials parallel or
perpendicular and then gently shake the probe vertically along the direct of the axial line
of the test material, the reading will change regularly. Select the minimum of the readings
as the accurate thickness of the materials.
The standard for the intersectional angle is determined by the curvature of the material.
For tubular material with bigger diameters, make the crosstalk isolating board
perpendicular to the axial line of the tube, for tubes with a smaller diameter, select two
methods, that is, making the intersectional angle parallel with and perpendicular to the
axial line and select the minimum value of the readings as the thickness measured.
22
7.4.5 Compound contour
In measuring materials with compound contour (such as elbows), the method introduced
in 2.5.4 may be used. The difference is that there is the need to measure the second TIME
to obtain two readings and take the smaller reading as the thickness of the point measured.
7.4.6 Non-parallel surface.
In order to obtain a satisfactory ultrasonic response, the other side of the test materials
must be parallel or on the same axial with the test surface. Otherwise, there will be errors
or no reading at all.
7.4.7 Effect of temperature of test material
The thickness and ultrasonic wave transmission speed are all affected by temperature. Is a
high accuracy is required, test block of the same material may be tested under the same
temperature are calculated for revision purposes. For iron and steel, high temperature will
cause bigger errors (the reading is smaller than the actual data), the method can also be
used.
7.4.8 Materials with big attenuation.
23
For some materials, such as fiber, porous and rough grained materials, the ultrasonic
waves would be deflected and attenuation of energy, so much so that the readings may be
abnormal of there may even be no readings (usually the abnormal reading is smaller than
the actual thickness). In such circumstances, the instrument is not applicable to test the
thickness.
7.5 The ultrasonic speed table of common industrial materials:
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Name of material
Aluminum
Zinc
Silver
Gold
Tin
Iron and steel
Brass
Copper
SUS
Acrylic resin
Water (20ºC)
Glycerin
Sodium silicate
Ultrasonic speed(m/s)
6260
4170
3600
3240
3230
5900
4640
4700
5790
2730
1480
1920
2350
Name of material
Acetic resin
Phosphor bronze
Pine resin
Glass
Inconel
Magnesium
MoNi alloy
Nickel
Steel4330 (low carbon)
Steel 330
Titanium
Zirconium
Nylon
Ultrasonic speed(m/s)
2670
3530
4430
5440
5720
6310
3020
5630
5850
5660
6070
4650
2620
Note: Different types and components of materials may have bigger range of
ultrasonic speed.
25
8. Prevention of measuring errors
8.1 Supper-thin materials
Any material whose thickness is lower than the low limit of the probe will measurement
errors. Instrument should be connected again for measuring the same material in order to
obtain the result of the minimum thickness.
In measuring super-thin materials, there might be such erroneous results as “dual deflection”
sometimes. That means that the displayed reading is twice as big as the actual thickness.
Another error is known as “pulse envelope, cyclic jumping”. The result is bigger than the
actual thickness. To prevent these errors, the critical thin materials should be measured
repeatedly for verification.
8.2 Rusty spots and eroded pits.
Rusty spots and eroded pots may cause the readings to change irregularly. Under extreme
circumstances, there is even no reading. It is hard to discover a small rusty spot. When a
convex is found or suspicion, care is needed to measure the area. Different positions of
angles of the probe crosstalk isolating board may be selected to carry measurements for
many times.
26
8.3 Error in identifying materials.
When the instrument is corrected for measuring one materials and it is used to measure
another kind of material, errors may occur. Attention should be paid to select the correct
ultrasonic speed.
When the ultrasonic speed is deviated from the corrected ultrasonic speed, it might cause
wrong results. Proper adjustments are needed in actual operation.
8.4 wear of the transducer
The transducer surface is made of acrylic resin. When in long use, the roughness may
increase, thus causing the result less accurate. If it has been determined that the error is
caused by roughness, 500# sand paper (the diameter of each piece of paper is 50~40µm) or
oil grinding stone may be used to grind the surface of the probe so that it will become
smooth and parallel. If that does not work, the probe must be changed.
8.5 Use of the ZERO key
The key is used only for correction by coupling the transducer onto the standard test block
on the instrument panel. It is not to be used on test blocks of any other kinds of materials.
Otherwise it will cause measurement errors.
27
8.6 Laminated and compound materials
It is impossible to measure the unbounded laminated materials, because the ultrasonic wave
can not penetrate the spaces that have not been bounded. As the ultrasonic waves spread in a
uniform speed in compound materials, instruments measuring thickness according to the
ultrasonic deflection theories are not applicable to measuring laminated or compound
materials.
8.7 Effect of oxidized layer of metals.
Some metals may correct very close oxidized layers in their surfaces, such as aluminum. The
oxidized layer and the base metal are closely bound together, without marked boundaries.
But the spread speed of ultrasonic wave for these two kinds of matters is not the same. So
error may occur, with different thickness of oxidized layers having measuring. A block
measured by micrometer may be selected from the test material as a test block for use in
correcting the instrument.
8.8 Abnormal reading
Operators should have the ability of identifying abnormal readings. Usually, rusty spots,
corrected pits and the wrong use of material or ultrasonic speed to correct the instruments
and flaws of the test materials may cause abnormal readings.
28
8.9 Use and choice of coupling agents
Coupling agent is used for transmitting high frequency ultrasonic energy between the probe
and the test material. Incorrect selection of the types of coupling agents or improper use may
cause errors or flashing of the coupling marks, making it unable to measure the thickness.
Coupling agent should be used in proper amount and coated evenly. Normally, the coupling
agent is laid over the surface of the test material. But when the measuring temperature is
high, the coupling agent is laid over the bottom of the transducer.
It is important to select the proper type of coupling agents. When the surface of the test
material is smooth, low viscosity of coupling agent should be used (coupling agents and
light machine oil are provided with the instrument). High viscosity coupling agents (such as
glycerin paste and lubricating grease) may be chosen for rough surface or when the test
piece is perpendicular to the surface and the top surface.
8.10 Protective sheath of transducer.
When measuring curved surface, transducer sheath should be used so as to measure the
thickness more accurately. Transducer protective sheath is optional purchasing.
9. Non-warranty parts.
1. Window, 2. Battery,
3. Transducer.
4.Test block. 5. Sheath of gauge. 6. Couplant
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