NDT INSPECTION

What is NDT Inspection?

Non-Destructive Testing (NDT) refers to inspection techniques that can be used to evaluate, analyze, and test properties of materials without causing any harm or damage. Sometimes called non-destructive examination (NDE) or non-destructive inspection (NDI), this type of testing is critical for shipyards, aircraft manufacturers, automotive production facilities, and fabrication processes where invisible cracks, weak spots, or failing welds could lead to dangerous conditions, critical failures, and catastrophic accidents.

Who uses NDT Inspection?

NDT is used in many different industries where precision is paramount and any failures could cause hazard or significant economic loss. Industries include:

• Automotive: NDT testing is used in manufacturing and post-manufacturing for inspection of individual components, as well as molded and welded parts.
• Aerospace: Aircraft must go through significant testing to ensure they uphold all standards and regulations during manufacture and ongoing maintenance.
• Oil & Gas: Pipes, boilers, and valves must be inspected for corrosion, erosion, and any welding damage.
• Manufacturing: Aluminum cases, steel turbine blades, or any molded parts require continual testing to minimize defects.
• Shipyards: Steel plates welded together to create the hull of ships and piping must be inspected for cracks or weak spots.
• Railways: Castings, cast wheels, engine components, tires, airbags, fuel injectors, and brake components all undergo significant testing during manufacturing processes and maintenance.
• Power generation and powerlines: Powerlines and facilities all undergo testing during installment and maintenance for voids, sleeve alignments, clamps, soldering, core cracks, and more.
• Ammunition and fuses: Military equipment, from large rocket motors to handheld firearm ammunition, must all be inspected for safety purposes.
• Art: NDT can be used to test authenticity, discover hidden secrets, and allow for reconstruction inspections in sculptures, paintings, and ancient artifacts.

What methods are there for conducting NDT Inspections?

There are a wide range of methods for conducting NDT Inspection. Each requires their own tools, preparation, and may be more or less useful depending on the project and materials being tested.

• Visual Testing: This is the simplest type of NDT Inspection. Visual Inspection requires the inspector to use his or her own eyes to inspect the materials. A flashlight, camera, or drone could be used to help the inspector see the inspection subject. Visual testing (VT) is an important first step, but obviously does not provide accurate measurements, nor give any information about internal materials or microscopic imperfections.
• Ultrasonic Test Method: The basic principle of ultrasonic testing (UT) is to use high-frequency sound waves to penetrate the material being tested, and then measure the time it takes for the sound waves to return after reflecting off of the material’s internal surfaces or defects. Ultrasonic testing is typically performed using a handheld or automated instrument called an ultrasonic flaw detector, which generates the sound waves and records the time and intensity of the echoes produced. A more advanced form of UT is Phased array ultrasonic testing (PAUT), uses an array of small ultrasonic transducers to create beams of sound waves that can be steered electronically.
• Electromagnetic Testing: Electromagnetic NDT, magnetic particle testing (MT) or magnetic particle inspection (EPI) uses magnetic fields and magnetic particles to flaws in ferromagnetic materials such as iron, nickel, and cobalt. In NDT it measures the strength of electrical currents in a magnetic field surrounding material to examine it. It is often used in industries such as aerospace, automotive, and manufacturing, where the need for efficient and reliable inspection methods is critical for safety and performance.
• Radiography Testing: Radiography NDT uses gamma or x-ray technology to identify imperfections. It is done by directing radiation from a radioactive isotope or x-ray generator through materials to create a photograph that reveals underlying aspects and shows variations in the density and thickness of the material, which can reveal the presence of internal defects such as cracks, voids, and inclusions. This method is very useful for uncovering imperfections, cracks, or alterations that would be invisible to the naked eye and more particularly useful for inspecting thick, complex components such as welds, castings, and forgings
• Liquid Penetrant Testing:  Also known as Penetrant Testing (PT), can be used to complement the forms of testing mentioned above by detecting surface-breaking defects that may not be visible, and to provide a more comprehensive inspection of materials and components.

What are the difficulties with conducting NDT Inspections?

Carrying out NDT inspections can be challenging. Onsite there may be meters of pipelines, various composites, either welded or produced by different techniques. Everything must be inspected thoroughly to ensure that no damage or cracks were missed and that all testing is completely accurate.

Often in manufacturing, production takes place during the daytime shift and then inspection is carried out during the night shift. This can lead to bottlenecks in production and inefficient time allocation if the inspectors missed something, or need to redo an inspection before production can continue.

Here are some of the most common challenges faced while conducting NDT inspections:

• Complexity of Equipment: Many NDT methods require specialized and complex equipment to perform inspections. These instruments need to be calibrated and maintained regularly to make sure that they remain accurate and reliable.
• Operator Skill and Training: The effectiveness of NDT inspections depend on the skill and experience of the operator. NDT operators require specific training and must have a thorough understanding of the NDT method being used as well as the principles underpinning it.
• Surface Preparation: The surface of the material being inspected needs to be prepared and cleaned well. For some materials and in some situations this can pose a challenge due to access and surface area.
• Sensitivity to Environmental Factors: Environmental factors such as temperature, humidity, and electromagnetic interference can have an impact on the accuracy of NDT inspections.

Here are some solutions to help overcome these challenges:

• Invest in Quality Equipment: Investing in quality equipment that can be properly maintained and calibrated will result in improved reliability of NDT inspections.
• Get NDT Operators trained and certified: Provide adequate training and certification for operators to improve their understanding of the principles and limitations of the NDT method they are using, and to improve quality of inspections.
• Conduct thorough Surface Preparation: Use specialized cleaning equipment and methods to ensure that the surface environment is thoroughly cleaned.
• Minimizing Environmental Factors: Measures can be taken to minimize the impact of environmental factors on NDT inspections, such as performing inspections in a controlled environment or using equipment designed to mitigate the effects of environmental factors.

Using Digital Radiography Technology for NDT Inspection

Digital Radiography (DR) is a superior method of NDT Inspection because it can save time, money, and provide accurate and instant imaging. With this type of technology, inspections can be done on the spot, with instant exposure and results, allowing for inspectors to approved or rejected work immediately. No development is required and files are immediately transmitted for higher level inspection and analysis. DR also saves costs because it does not require development materials such as film. This increases productivity, which is also a money saver.

Digital Radiography Technology uses x-ray imaging to scan equipment. While traditional x-ray technology requires waiting for film to be developed to see the scans, DR Technology allows for instant results. Images are displayed on a laptop or tablet screen. In cases where multiple images are required, each image is automatically stitched together to create a larger picture to be inspected. Any images that are unclear or need to be adjusted can be reshot immediately.

Vidisco is a leading developer of DR Technology for safe and accurate NDT Inspection. Founded in 1988 by military and professional experts, Vidisco pioneered the digital x-ray industry and is used by top military, security, and industrial organizations worldwide.

Vidisco Digital Radiography testing systems are portable, fitting into one box on wheels, where it can be transported from place to place and easily set up. The system is battery operated and wireless, allowing for up to five hours of scanning on battery life and unlimited scanning while plugged in.

Using the equipment, inspectors can take multiple images of whatever equipment is being scanned and instantly see images on the screen. The images show thickness measurements, water penetration, cracks, and any abnormalities.

Because the system uses low doses of x-rays, only small area closures are required for inspection, allowing inspection to commence in parallel with production. Repairs can also be completed immediately after the imperfections are found.

In today’s world, businesses can’t afford to be slowed down by inspection processes, which is why forward-thinking companies are moving toward DR Technology for NDT Inspections.

Are you interested in learning more about how Vidisco’s Digital Radiography (DR) Technology can improve your NDT Inspection process? Read more about our solutions and how we can personalize them to your business here