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Hillger Ing. Büro
was founded in 1984 and develops special ultrasonic imaging systems for high-tech materials.

1747 views
05:18 Sep-25-2004

S.G.

Consultant
Enrico Enterprises,
India,
Joined Jul 2004
20
Pizo-elecric crystal frequency variation

Hi, Friendes

During the assembling of the ultrasonic probe, nominal frequency of the Pizo-electric crystal get change is it true? What are the factores? How we can minimise that?

Frequency is depend on the thickness of the crystal and less thicness means high frequency.

As per the ASTM 10% is acceptable is it right?


 
02:54 Sep-27-2004

Paul A. Meyer

R & D,
GE Inspection Technologies,
USA,
Joined Nov 1998
47
Re: Pizo-elecric crystal frequency variation Hello,
Piezoelectric elements are initially characterized while connected to a network analyzer and having no mechanical loads applied. As they are built into transducers, damping material, matching layers, and electrical tuning components are added to produce the desired performance. Therefore, to optimize the perfromance of the completed probe, the initial piezoelctric element parameters become design variables. For example, to build a highly damped 5 MHz probe, a 6 MHz piezoelectric element may be required to account for mechanical and electrical loads. All components in the probe design need to be considered to optimize probe performance. There are transducer models that can be used for this purpose. Many are based on the KLM transmission line concept published many years ago. These are very helpful but are 1-dimensional, lateral effects are not considered. FEA analysis is more detailed but more time comsuming and computationally intensive.
Paul

----------- Start Original Message -----------
: Hi, Friendes
: During the assembling of the ultrasonic probe, nominal frequency of the Pizo-electric crystal get change is it true? What are the factores? How we can minimise that?
: Frequency is depend on the thickness of the crystal and less thicness means high frequency.
: As per the ASTM 10% is acceptable is it right?
------------ End Original Message ------------




 
01:58 Sep-27-2004

Ed Ginzel

R & D, -
Materials Research Institute,
Canada,
Joined Nov 1998
1185
Re: Pizo-elecric crystal frequency variation Paul:
Your mention of how "loading" reduces the ideal centre frequency determined by the frequency constant is well worth noting. I have also noted that it is very important to define the method of frequency assessment.
Should you use pulse-echo or transmit-receive? Should the assessment be made in water or in the material that you are designing the probe to operate in?
Be careful if you are mounting the element on a refracting wedge. The wedge material will restrict frequency content.
At what distance should you measure the frequency?
If using a digital scope for analysis what is the digitising frequency that should be used?
Finally, there are several "frequencies" that may be used to describe the probe; design, nominal, centre, peak, or upper (or lower) 6dB edge. (I once bought a 50MHz PVDF probe that I could not get to pulse with a peak frequency of better than about 28MHz. The upper and lower 6dB were about 50 and 20MHz so some components were at the "nominal" but I did not understand how it was marketed at 50MHz.

There are also pulse characteristics to consider. A spike pulser will not produce the same frequency content as a square-wave or chopped sine-wave pulser.
Regards
Ed

----------- Start Original Message -----------
: Hello,
: Piezoelectric elements are initially characterized while connected to a network analyzer and having no mechanical loads applied. As they are built into transducers, damping material, matching layers, and electrical tuning components are added to produce the desired performance. Therefore, to optimize the perfromance of the completed probe, the initial piezoelctric element parameters become design variables. For example, to build a highly damped 5 MHz probe, a 6 MHz piezoelectric element may be required to account for mechanical and electrical loads. All components in the probe design need to be considered to optimize probe performance. There are transducer models that can be used for this purpose. Many are based on the KLM transmission line concept published many years ago. These are very helpful but are 1-dimensional, lateral effects are not considered. FEA analysis is more detailed but more time comsuming and computationally intensive.
: Paul
: : Hi, Friendes
: : During the assembling of the ultrasonic probe, nominal frequency of the Pizo-electric crystal get change is it true? What are the factores? How we can minimise that?
: : Frequency is depend on the thickness of the crystal and less thicness means high frequency.
: : As per the ASTM 10% is acceptable is it right?
------------ End Original Message ------------




 
00:39 Sep-29-2004

Amry Amin

R & D
Malaysian Inst. for Nuclear Technology Research,
Malaysia,
Joined Aug 2002
4
Re: Pizo-elecric crystal frequency variation Hello,

Does backing material, front face material of the disc and load of the medium have effect on the frequency of a complete probe? I have made a model of a probe considering the layers using Mason circuit and I found that the resonant frequency varies when the parameters of the layers are altered.

----------- Start Original Message -----------
: Hello,
: Piezoelectric elements are initially characterized while connected to a network analyzer and having no mechanical loads applied. As they are built into transducers, damping material, matching layers, and electrical tuning components are added to produce the desired performance. Therefore, to optimize the perfromance of the completed probe, the initial piezoelctric element parameters become design variables. For example, to build a highly damped 5 MHz probe, a 6 MHz piezoelectric element may be required to account for mechanical and electrical loads. All components in the probe design need to be considered to optimize probe performance. There are transducer models that can be used for this purpose. Many are based on the KLM transmission line concept published many years ago. These are very helpful but are 1-dimensional, lateral effects are not considered. FEA analysis is more detailed but more time comsuming and computationally intensive.
: Paul
: : Hi, Friendes
: : During the assembling of the ultrasonic probe, nominal frequency of the Pizo-electric crystal get change is it true? What are the factores? How we can minimise that?
: : Frequency is depend on the thickness of the crystal and less thicness means high frequency.
: : As per the ASTM 10% is acceptable is it right?
------------ End Original Message ------------




 
03:43 Oct-01-2004

Paul A. Meyer

R & D,
GE Inspection Technologies,
USA,
Joined Nov 1998
47
Re: Pizo-elecric crystal frequency variation Hello Amry,
The reflection and transmission factors for a thin layer depend on the wavelength-to-thickness ratio. Most ultrasound transducers emit pulses with fractional bandwidths greater than 40%. The apparent mechanical load "seen" by the ceramic through the face will depend on the wavelength (frequency). If the thickness of the layer is changed, the variation of load with wavelength also changes, which changes the response of the probe. You are approaching the problem correctly by modeling the design for your particular need. You will find that multiple face layers can improve probe performance in many situations.
Paul
----------- Start Original Message -----------
: Hello,
: Does backing material, front face material of the disc and load of the medium have effect on the frequency of a complete probe? I have made a model of a probe considering the layers using Mason circuit and I found that the resonant frequency varies when the parameters of the layers are altered.
: : Hello,
: : Piezoelectric elements are initially characterized while connected to a network analyzer and having no mechanical loads applied. As they are built into transducers, damping material, matching layers, and electrical tuning components are added to produce the desired performance. Therefore, to optimize the perfromance of the completed probe, the initial piezoelctric element parameters become design variables. For example, to build a highly damped 5 MHz probe, a 6 MHz piezoelectric element may be required to account for mechanical and electrical loads. All components in the probe design need to be considered to optimize probe performance. There are transducer models that can be used for this purpose. Many are based on the KLM transmission line concept published many years ago. These are very helpful but are 1-dimensional, lateral effects are not considered. FEA analysis is more detailed but more time comsuming and computationally intensive.
: : Paul
: : : Hi, Friendes
: : : During the assembling of the ultrasonic probe, nominal frequency of the Pizo-electric crystal get change is it true? What are the factores? How we can minimise that?
: : : Frequency is depend on the thickness of the crystal and less thicness means high frequency.
: : : As per the ASTM 10% is acceptable is it right?
------------ End Original Message ------------




 
07:07 Feb-21-2005
Dan Walden
Re: Pizo-elecric crystal frequency variation I have a fountain that has water and gas flames. I would like to know if there is some way to design some way to create an electrical lighter, so flame is kept burning.





 
06:12 Mar-02-2005
nitin joshi
miro piezoelectric crystal plese send me complete tutorial about micro piezo electric crystal


 
04:01 Dec-31-2005
Bhavesh
Re: Pizo-elecric crystal frequency variation ----------- Start Original Message -----------
hello,
i have no idea for ultrasonic welding in used transuder details for pizo. i have make for 20khz frequency what about parametaer of pizo design and what about size and what about attachment to pizo for make trasuder for 2o khz.


 


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