Ultrasonic Transducer FAQs

A piezoelectric ultrasonic transducer is a device that converts electrical energy into mechanical vibrations, specifically ultrasonic waves, and vice versa. This conversion is based on the piezoelectric effect, a phenomenon where certain materials generate an electrical charge when subjected to mechanical stress, or conversely, deform when an electric field is applied. These transducers are fundamental components in a wide array of applications, from medical imaging and industrial inspection to cleaning and material processing.

1. Do you have a catalog of ultrasonic transducers?

Yes, a product catalog is available for download, showcasing the range of ultrasonic transducers that we produce. This catalog includes specifications and details relevant for various applications.

2. Can you manufacture ultrasonic transducers according to customers’ needs?

Absolutely. Our manufacturing capabilities are highly adaptable, allowing us to produce custom designs provided by our customers, including those utilizing conventional piezo composite elements. We specialize in ultrasonic transducers, and therefore, our ability to meet custom manufacturing requirements, deadlines, and cost budgets is superior to many other manufacturers. We also offer sales packages on economies of scale, reducing costs for our customers. We actively involve customers in our next-generation designs to ensure our future product lines meet their needs effectively.

3. What frequency operating ranges do you recommend?

While ultrasonic transducers can typically operate in a frequency range of 17 kHz to 2 MHz, for optimal performance, we recommend operating within the range of 50 kHz to 1 MHz. This range provides a good balance between resolution and penetration for most common applications.

4. What are the cleaning frequencies of ultrasonic transducers?

The appropriate cleaning frequency depends on the specific cleaning requirements. Lower frequencies are more effective for removing heavy contaminants from robust components, while higher frequencies are better for delicate parts with smaller contaminants.

Frequency Range	Application
Below 80 kHz	Rugged components with heavy contaminants
Above 80 kHz	Delicate components with smaller contaminants

It is also possible to use different frequencies sequentially for optimal cleaning results, with lower frequencies for breaking down large contaminants and higher frequencies for clearing out smaller particles. However, always ensure the components can withstand the chosen frequencies to avoid damage. For broad-spectrum cleaning, we recommend a combination of lower frequencies (40 kHz to 72 kHz) for short periods and higher frequencies (104 kHz to 170 kHz) for longer periods.

5. How to connect multiple ultrasonic transducers?

Ultrasonic transducers should be connected in parallel. This configuration ensures that each transducer receives the same voltage, optimizing their performance.

6. Ultrasonic transducer bonding process

The bonding process is critical for transducer reliability and performance. Here’s a breakdown:

1. Epoxy Glue: Use epoxy glue with minimal shrinkage and thermal expansion properties to reduce stress and improve oscillator reliability. Epoxy A and B are suitable options.
2. Surface Preparation: Sun blasting the adhesive surface significantly increases adhesive strength.
3. Cleaning: Clean the cemented surface with a solvent like absolute alcohol or acetone.
4. Vertical Correction: During nail bonding, take care in vertical correction when planting the nail.
5. Adhesive Curing: Control the pre-loaded stress and consistency during adhesive curing.
6. Impedance Control: Establish impedance control during the gluing process to reduce impedance and increase electro-acoustic output.
7. Load Distribution: Improve energy load distribution using impedance testing after gluing.
8. Wiring: Ensure wiring is soft, insulation is strong, and welding is reliable.
9. Insulation Test: Test insulation after wiring to check for defects.
10. Debugging: Carry out debugging between 40-50 ℃ but maintain operating temperatures below 80 ℃.

7. What is piezoelectric effect?

The piezoelectric effect is the ability of certain materials to generate an electrical charge in response to applied mechanical stress, or conversely, to produce mechanical strain when an electric field is applied. This phenomenon is fundamental to the operation of piezoelectric ultrasonic transducers. Materials like quartz, lead zirconate titanate (PZT), and various ceramics exhibit this effect.

8. How does a piezoelectric ultrasonic transducer work?

A piezoelectric ultrasonic transducer operates based on the reverse piezoelectric effect. Here’s how it works:

1. Electrical Excitation: An alternating electrical signal is applied to the piezoelectric element.
2. Mechanical Vibration: The piezoelectric material expands and contracts in response to the oscillating electric field.
3. Sound Wave Generation: These vibrations create pressure waves, i.e., ultrasound, in a coupling medium like air, liquid, or solid.
4. Reception: The transducer can also operate as a receiver, converting mechanical vibrations from incoming ultrasonic waves into an electrical signal.

9. What are the key components of a piezoelectric ultrasonic transducer?

Key components include:

• Piezoelectric Element: The core of the transducer, made of piezoelectric material.
• Electrodes: Conductive layers facilitating the application of electric fields and signal collection.
• Housing: The casing protecting the piezoelectric element.
• Matching Layer(s): Improves impedance matching for efficient energy transfer.
• Backing Material: Absorbs rear ultrasound waves to prevent interference.

10. What are the characteristics of PZT series and their applications?

PZT materials are widely used in ultrasonic transducers:

• PZT8: Used in high-power applications like cleaning and welding due to its thermal stability and lower heating.
• PZT4: Suitable when thermal stability is a requirement, offering higher Curie temperature, better stability, and temperature control.

11. What types of piezoelectric materials are commonly used?

The selection of piezoelectric material affects the performance characteristics. Common materials include:

Material	Advantages	Disadvantages	Typical Applications
Lead Zirconate Titanate (PZT)	High piezoelectric coefficients, versatile, widely available, cost-effective	Contains lead (environmental concerns), lower operating temperature than others	General purpose, medical imaging, industrial applications
Quartz	High stability, good mechanical properties, high precision	Lower piezoelectric coefficient, brittle, relatively expensive	High-precision measurements, frequency control, delay lines
Lithium Niobate	High-temperature stability, good acoustic performance	Higher cost, not suitable for all applications	High-temperature ultrasonic applications
Single Crystal Piezoelectric	Superior piezoelectric properties, high sensitivity and bandwidth, low hysteresis	Expensive, manufacturing limitations	High-precision applications, medical and industrial NDT applications, such as phased arrays
Piezoelectric Polymer	Flexible, lightweight, low cost, ease of manufacturing, good acoustic matching with tissue	Lower piezoelectric coefficient, limited temperature range	Medical devices, non-destructive testing, wearable sensors, and flexible sensors

12. What are the key performance parameters of a transducer?

Key parameters include:

• Frequency: The number of vibrations per second (Hz), determining resolution and penetration.
• Bandwidth: The range of frequencies where the transducer operates efficiently.
• Sensitivity: Efficiency of conversion between electrical and acoustic energy.
• Impedance: Opposition to the flow of electrical/acoustic energy; proper matching is crucial.
• Efficiency: Ratio of acoustic output power to electrical input power.
• Beam Profile: The spatial distribution of the ultrasonic field.

13. What are common applications of piezoelectric ultrasonic transducers?

They are widely used in:

• Medical Imaging: Ultrasound imaging for diagnosis, monitoring, and guidance of procedures.
• Industrial NDT: Detecting flaws in materials without damage.
• Industrial Cleaning: Removing contaminants from parts and materials.
• Distance Measurement & Sensing: Proximity sensors, level detectors, distance measuring.
• Flow Measurement: Measuring the flow rate of liquids and gases.
• Atomization & Nebulization: Producing fine mists in humidifiers and nebulizers.

14. What are the considerations when selecting an ultrasonic transducer?

Key considerations include:

• Operating Frequency: Chosen based on desired resolution and penetration depth.
• Transducer Size and Shape: Determined by the application space and placement.
• Piezoelectric Material: Selected based on performance requirements and cost.
• Bandwidth: Consider if pulse or continuous waves are used.
• Impedance Matching: Maximize energy transfer between transducer and medium.
• Environmental Factors: Temperature, humidity, and chemical exposure resistance.
• Application Specific Needs: Custom designs available for specialized applications.
• Budget: Consider performance, longevity, and robustness.

15. How is a transducer’s lifespan?

Lifespan is affected by:

• Operating Conditions: Extreme temperatures, high humidity, and chemicals can reduce lifespan.
• Input Power: High power operation for extended periods can cause material fatigue.
• Physical Handling: Impacts and mishandling cause damage.
• Material Properties: The inherent durability and chemical stability of the material affects longevity.
• Design and Manufacturing Quality: Well-designed and properly manufactured transducers have a longer lifespan.

16. How can transducers be maintained?

Proper maintenance extends lifespan:

• Storage: Store transducers in a dry, temperature-controlled environment.
• Cleaning: Gently clean the surface with a soft, lint-free cloth, avoiding abrasive cleaners and solvents.
• Inspection: Regularly inspect for cracks, damage, and connection issues.
• Proper Handling: Handle transducers carefully to avoid physical stress.
• Environmental Protection: Protect transducers from harsh chemicals and environments.
• Regular Calibration: Periodic recalibration may be needed for accurate measurements.

In conclusion, piezoelectric ultrasonic transducers are essential in a wide array of applications due to their unique properties. Proper selection, operation, and maintenance are crucial for optimal performance and longevity. Companies like Beijing Ultrasonic are at the forefront of this technology, providing reliable and high-quality solutions tailored to diverse applications.