Background
X-ray inspection is an invaluable part of Ford’s Materials Technology Centre as it strives to develop new materials and components for tomorrow’s cars. Since the removal of the open X-ray system, large lead-lined room, and wet plate film-processing laboratory from the Materials Science Department in 1999, X-ray inspection has been outsourced on an ad-hoc basis. However, since acquiring one of the latest developments in real-time X-ray inspection technology, the HMX 225 ST from X-Tek Systems last year, the department has not only reduced the cost of having to send components and systems to external test houses, but is expanding the use of X-ray non-destructive testing (NDT) in automotive inspection across a broad range of applications.
How Dependent is Ford on X-Ray Inspection?
The quality and quantity of X-ray inspection work Ford are now completing is a quantum leap ahead of what they were achieving before. The old X-ray room was used about four to six times a year for projects lasting for between one and two weeks, while the real-time X-ray system is used virtually every day. The time spent using the system is highly dependent on the aim of the investigation, material type and number of components, but typically most investigations are completed within one to two days if a few components are being inspected and computed tomography is not required.
Advantages of Computer Controlled X-Ray Inspection Equipment
A key feature of the HMX 225 ST system is image quality The microfocus X-ray system uses a very finely focused X-ray beam, with a focal spot size of less than 5 microns required for the generation of high magnification and high resolution images. Furthermore, unlike wet film technology, no chemical development is needed so images can be acquired in a fraction of the time and artificial features cannot be introduced during the development process.
What Materials Can be Analysed by X-Ray Inspection
The range of materials and components that Dunton deals with every day includes metal castings, metal sheet, powertrain components, polymers (including leather, seating, interior and exterior plastics), rubber, fasteners, chemicals, fluids, paints, and advanced materials, such as carbon fibre, composites and adhesives. Until recently many components were routinely sectioned on arrival in the department to allow detailed visual inspection. Now, in a growing number of cases, Ford engineers are using the X-ray system to carry out faster and more cost-effective test inspections.
REAL TIME X-RAY INSPECTION
Posted by Sina Ev Yemekleri | Monday, November 26, 2007 | Advantages of Computer Controlled X-Ray, Ford on X-Ray Inspection, How Dependent, What Materials Can be Analysed by X-Ray Inspection | 0 comments »Nondestructive testing (NDT)
Posted by haksoft | Sunday, November 25, 2007 | Non-destructive | 0 comments »Nondestructive testing (NDT) are noninvasive techniques to determine the integrity of a material, component or structure or quantitatively measure some characteristic of an object. In contrast to destructive testing, NDT is an assessment without doing harm, stress or destroying the test object. The destruction of the test object usually makes destructive testing more costly and it is also inappropriate in many circumstances.
NDT plays a crucial role in ensuring cost effective operation, safety and reliability of plant, with resultant benefit to the community. NDT is used in a wide range of industrial areas and is used at almost any stage in the production or life cycle of many components. The mainstream applications are in aerospace, power generation, automotive, railway, petrochemical and pipeline markets. NDT of welds is one of the most used applications. It is very difficult to weld or mold a solid object that has no risk of breaking in service, so testing at manufacture and during use is often essential.
While originally NDT was applied only for safety reasons it is today widely accepted as cost saving technique in the quality assurance process. Unfortunately NDT is still not used in many areas where human life or ecology is in danger. Some may prefer to pay the lower costs of claims after an accident than applying of NDT. That is a form of unacceptable risk management. Disasters like the railway accident in Eschede Germany in 1998 is only one example, there are many others.
For implementation of NDT it is important to describe what shall be found and what to reject. A completely flawless production is almost never possible. For this reason testing specifications are indispensable. Nowadays there exists a great number of standards and acceptance regulations. They describe the limit between good and bad conditions, but also often which specific NDT method has to be used.
The reliability of an NDT Method is an essential issue. But a comparison of methods is only significant if it is referring to the same task. Each NDT method has its own set of advantages and disadvantages and, therefore, some are better suited than others for a particular application. By use of artificial flaws, the threshold of the sensitivity of a testing system has to be determined. If the the sensitivity is to low defective test objects are not always recognized. If the sensitivity is too high parts with smaller flaws are rejected which would have been of no consequence to the serviceability of the component. With statistical methods it is possible to look closer into the field of uncertainly. Methods such as Probability of Detection (POD) or the ROC-method "Relative Operating Characteristics" are examples of the statistical analysis methods. Also the aspect of human errors has to be taken into account when determining the overall reliability.
Personnel Qualification is an important aspect of non-destructive evaluation. NDT techniques rely heavily on human skill and knowledge for the correct assessment and interpretation of test results. Proper and adequate training and certification of NDT personnel is therefore a must to ensure that the capabilities of the techniques are fully exploited. There are a number of published international and regional standards covering the certification of competence of personnel. The EN 473 (Qualification and certification of NDT personnel - General Principles) was developed specifically for the European Union for which the SNT-TC-1A is the American equivalent.
The nine most common NDT Methods are shown in the main index of this encyclopedia. In order of most used, they are: Ultrasonic Testing (UT), Radiographic Testing (RT), Electromagnetic Testing (ET) in which Eddy Current Testing (ECT) is well know and Acoustic Emission (AE or AET). Besides the main NDT methods a lot of other NDT techniques are available, such as Shearography Holography, Microwave and many more and new methods are being constantly researched and developed.
NDT Applications and LimitationsNDT Method | Applications | Limitations |
Liquid Penetrant |
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Magnetic Particle |
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Eddy Current |
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Ultrasonics |
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Radiography Neutron |
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Radiography X-ray |
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Radiography Gamma |
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