Operation Manual
Hardness Tester NOVOTEST T-UD3
Page. 12
−
<PHOTO>;
−
<BRIGHTNES>;
−
<PALETTE>;
−
<SOUND>;
−
<RESULT>;
−
<VOLUME>;
−
<AUTO OFF>;
−
<RETRO>;
−
<FLASH>;
−
<TOLERANCE>;
−
<FILTER>;
−
<FILTER MODE>.
5.
<MEMORY CARD>:
−
<SAVE>;
−
<LOAD>;
−
<CLEAR>.
6.
<INFORMATION>:
−
About dealers;
−
About the device.
7.
Two-way communication with PC:
−
Data transfer;
−
Transfer of calibration settings;
−
Interface change.
1.6.2 Leeb measurement principle (Leeb)
The dynamic principle probe (rebound method) is a separately executed device connected to the
electronic unit by means of a cable.
The principle of measuring hardness is based on the determination of the velocity ratio of impact
and rebound of the striker (impact body) inside the probe. Carbide ball is located at the end of the
impact body, directly in contacting with the material at the moment of impact. Inside of the impact
body is a permanent magnet. The striker, after pressing the trigger button, is ejected onto the testing
surface by a pre-charged spring. While this, the striker moves inside the inductor coil and, with its
magnetic field, induces an electromotive force (EMF) in it. The signal from the output of the induction
coil is fed to the input of the electronic unit, where it is converted into a hardness value of the selected
scale and displayed.
This method is particularly suitable for hardness measurements on solid products, coarse-grained
products, forged and cast products.
The design of the dynamic probe allows user to make many measurements for a short time, and
working with it does not require special skills, such as with an UCI probe.
1.6.3 Ultrasonic Contact Impedance method
Ultrasonic probe (UCI - ultrasonic contact impedance method) is a separate device connected to
an electronic unit by means of the cable.
The probe basically uses a steel rod with a diamond pyramid at the end, which is an Acoustic
Resonator (Oscillating Rod) of the built-in self-oscillator of ultrasonic frequency. When the diamond
pyramid penetrating into the testing object under the fixed force of the calibrated spring, the resonant
frequency of the resonator changes in accordance with the material hardness. The relative change in
the frequency of the resonator is converted by the electronic unit into the hardness value on the
selected scale and displayed.