Digital Radiography (DR) overview
Radiographic testing is a very common form of inspection for industrial applications, across all industries. Over the years, traditional x-ray processes have become obsolete and are being replaced with advanced radiographic testing techniques for the digital age. Digital radiography is a sustainable method of testing, which meets growing industry needs. Users often seek nondestructive testing labs for all digital radiography testing projects for accurate and quick results.
What is Digital Radiography?
Digital radiography (digital x-ray) is a form of x-ray imaging, where screen films and photographic films are replaced with a digitized detector. According to the American Society of Nondestructive Testing (ASNT), digital radiography digitizes the radiation that passes through an object directly on to a computer for review and analysis.
How does Digital radiography differ from other Radiographic Testing?
There are three distinct types of radiographic testing techniques:
- Film radiography
- Computed radiography (CR)
- Digital radiography (DR)
Digital radiography differs from the remaining three techniques because it provides immediate imaging results available for inspection and analysis. With film radiography, there is use of films which require time for processing and inspection. Computed radiography uses a combination of film and digital radiography. Although it uses film cassettes to capture the resulting image, they are processed using a laser reader, which translates data into a digital image. Computed Tomography uses a digital detector to capture images, however, these are reconstructed into a 3D model, requiring more time for an incomparable resulting image in 3D. Depending on the purpose of the testing project, one of the four different radiographic testing techniques can be beneficial for internal part analysis.
How Digital Radiography works
In order for digital radiography to work, two factors play a significant role:
- X-ray source
- Detector panel
A part is placed in the middle of an x-ray source and detector panel. The radiation released from the x-ray source shoots through the part and remaining radiation is captured by the detector panel. 2D x-ray images that are captured with the detector panel are immediately available to view on a computer. The higher the density of the part, the more radiation it will absorb. Since defective areas within a part (such as cracks or voids) consist of no density, radiation will pass right through and be captured with the detector panel. The resulting image will be in grayscale value. All defects such as porosity will be shown in darker scale value – black – whereas all areas with varying densities will be shown in varying lighter scale value – white.
Uses of Digital radiography
The uses of digital radiography vary according to the project requirements. Since this is a non-destructive testing method, it becomes very useful across all stages of a parts life cycle. The most common uses for digital x-ray include:
- Pre-production evaluation and validation of part
- Ensures safety and reliability of part
- Failure investigation tool
- Identify, locate and measure defects
- Production lot inspection
- Density variations can be analyzed for structural evaluation
- Quality control management tool
- Quick, cost effective and accurate
- Part approval/rejection tool
- Ability to use part after testing and analysis+
- Qualify and approve part components
Applications of digital radiography
For industrial applications, radiography can be used in many different ways for different industries. This x-ray technology reduces costs and minimizes time for reviewing and analyzing parts. Applications vary by industry, some of which may include:
- Packaging – Ex. Find leakage issues in packaged goods
- Aerospace – Ex. find fatigue in Castings
- Military & Defense – Ex. Confirm geometry and develop FAI reports for ballistics
- Medical Device – Ex. Locate foreign material in medical devices such as an insulin pen
- Automotive – Ex. Find flaws such as porosity in Piston Head
- Consumer Products – Ex. Evaluate wall thickness of a bottled part
Benefits of digital radiography
Digital radiography testing provides many benefits to its users for industrial applications. Listed below are a few direct benefits of digital x-ray for industrial applications:
- Non-destructive method of inspection
- Cut costs and time relative to other testing methods
- Research & Development guidance and insight
- Full failure investigation
- Part confirmation and verification
- Detect internal flaws and foreign material
History of digital radiography
In 1895, Wilhelm Rontgen discovered x-rays while experimenting. The “x” is to signify the unknown form of radiation. Rontgen figured this would change once there was further understanding of radiation. Shortly after the discovery, x-rays were used for medical applications to diagnose and analyze the human body. Industrial applications were the next use for x-rays, inspecting and analyze aerospace components. With growing industry needs, technologically advanced forms of x-rays were introduced, which were classified under radiographic testing techniques. Today, users are able to utilize different radiographic testing techniques to inspect anything from medical devices to military equipment.