In today’s manufacturing landscape, ensuring the integrity of materials while not causing any damage is essential. Dye Penetrant Inspection (DPI) and Acoustic Resonance Testing (ART) are both non-destructive testing (NDT) methods that can identify defects.
While DPI is well-known for its ability to identify surface defects, ART offers an advanced technique which indicates the structural integrity of a part through acoustic analysis. This article explores both methods, helping you determine which method aligns best with your production needs.
What is Dye Penetrant Inspection?
DPI is a well-established NDT technique that utilises the principle of capillary action to detect surface defects in non-porous materials. During the process, a coloured or fluorescent dye is applied to the component’s surface, allowing it to seep into any defects. After a designated dwell time, excess penetrant is removed and a developer is applied to draw any dye trapped in cracks or pores back to the surface. Specific lighting, such as red or ultraviolet, is then employed to illuminate the defects.
Advantages of Dye Penetrant Inspection:
Requires minimal training and equipment
A relatively low cost non-destructive testing method
Can identify cracks, seams and other flaws on the surface
Limitations:
Cannot detect sub-surface defects (e.g. inclusions, porosity, laminations)
Chemical penetrants can be hazardous and require operators to use Personal Protective Equipment (PPE)
Time consuming as the dwell time of the penetrant can take 5 to 30 minutes for each part
Inspection is performed on a smooth, clean surface and can result in false indications when conducted on rough surfaces, such as welds
What is Acoustic Resonance Testing (ART)?
Acoustic Resonance Testing is an advanced NDT method that assesses structural integrity by measuring the resonance frequencies of a component. Every material possesses unique resonance frequencies based on its properties and geometry. By exciting components through mechanical impact or vibration and analysing its acoustic response, ART can detect various defects, including cracks, inclusions, and porosity. Traditionally, it is performed with a hammer and human operator who listens to the sound upon impact. The operator then uses their trained ear to determine if the part is defective.
RESONIKS has revloutionised this traditional method through its AI algorithm that significantly enhances the power of the Acoustic Resonance Testing. Leveraging advanced machine learning models, RESONIKS indexes the resonant signatures of defect-free parts. The AI model then analyses the data to create a sensitive model capable of detecting even the slightest of anomalies in new production parts. This process is completed in seconds, and is not limited to surface type, material type, or depth. Therefore, any parts that are 3D printed, porous, or have rough surfaces can be objectively assessed.
Advantages of RESONIKS Acoustic Resonance Testing:
Detects a large variety of surface and bulk defects (e.g. cracks, porosity, inclusions, laminations and weld defects)
Can be used with various materials, non-porous and porous
Quickly identifies defects making it ideal for high-volume production
Ability to easily integrate into the production line
Doesn’t require a skilled operator
A low cost alternative to traditional NDT methods
Limitations:
Focuses on identifying whether a part is good or bad, rather than locating the exact location of the defect
Not suitable for one-off testing as a batch of reference parts are required for machine learning
Conclusion
Both Dye Penetrant Inspection and Acoustic Resonance Testing offer valuable non-destructive testing capabilities. DPI excels in detecting surface defects, while ART provides deeper insights into structural integrity through advanced resonance analysis. By understanding the strengths and limitations of each method, you can select the method that best suits your production process. As automation and AI continue to shape the future of NDT and manufacturing, integrating advanced techniques like RESONIKS’ AI-driven ART offers cutting-edge advantages in production efficiency and defect detection.
