Defect detection technology is a powerful guarantee to improve product quality, and has a positive effect on reducing or avoiding accidents caused by defects. Industrial CT as a practical non-destructive testing technology, has been widely used in aviation, petroleum, steel, machinery, automotive, mining and other fields, it can be in a non-destructive state, accurate detection of the internal structure of the workpiece.
? The purpose of industrial CT image defect detection is to find the defects of the workpiece from the CT image, and obtain the most accurate information possible about the defects. For most people, CT (computed tomography) probably refers to the medical discipline of CT technology. In fact, the application of CT has long been extended to the industrial measurement industry. Industrial CT technology has emerged as industrial measurement has shifted from external conventional measurements to internal non-destructive analysis and full-size measurements.
? In recent years, industrial CT has been hailed as the future trend of measurement technology by virtue of its powerful detection technology and gradually wide range of applications. According to the data, the market size of China's industrial CT inspection system market reached 1.09 billion yuan in 2017, and it is expected that the market size of China's industrial CT inspection system market will reach 1.63 billion yuan by 2021.
? What is industrial CT?
? Industrial CT is industrial computed tomography imaging, it can be in the detection of the object without damage to the conditions, in the form of two-dimensional tomographic images or three-dimensional stereoscopic images, clear, accurate, intuitive display of the internal structure of the object to be detected, the composition of the material and defective condition. The basic principle of industrial CT is based on the weakening and absorption characteristics of radiation in the object to be detected, with the material to the radiation absorption capacity and material properties. Therefore, the use of radionuclides or other sources of radiation emitted, with a certain energy and intensity of X-rays, in the detected objects in the attenuation pattern and distribution, it is possible to display by the detector to obtain detailed information on the inside of the object, and finally with computer information processing and image reconstruction technology, in the form of an image to show.
? What are the advantages of industrial CT?
? (1) Accurate positioning, the image is easier to identify
? Conventional ray detection technology is mainly a three-dimensional object projected onto a two-dimensional plane, which is easy to cause the superposition of image information, if you want to get the information on the image, without experience, it is very difficult to accurately locate and quantitatively measure the target. Industrial CT is able to provide two-dimensional or three-dimensional images when inspecting workpieces, and the target to be measured will not be obscured by surrounding detailed features, so the resulting image is very easy to recognize. The image is easy to recognize, and the specific spatial location, shape and size of the target features can be obtained directly from the image.
? (2)Higher density resolution
? Industrial CT has an outstanding density resolution, high-quality CT image density resolution can even reach 0.3%, compared with conventional non-destructive testing technology, at least one order of magnitude higher.
? (3)High dynamic response range
? Industrial CT with high-performance detectors, the dynamic response range of the detector can reach more than 106, much higher than film and image intensifier.
? (4) Images are easier to store, transmit, analyze and process
? As the industrial CT image intuitive, image gray scale and workpiece materials, geometric structure, components and density characteristics correspond to, not only can get the shape, location and size of defects and other information, combined with the density analysis technology, but also to determine the nature of the defects, so that the defects of the long-term plagued by nondestructive testing personnel spatial positioning, depth quantification and comprehensive characterization of the problem of a more direct way to solve it.
? Application of industrial CT
? (1) workpiece internal pores, cracks and other defects detection
? Industrial CT equipment has high detection sensitivity for various common defects such as porosity, inclusions, pinholes, shrinkage holes, delamination, cracks, etc., and can accurately determine the geometric size of defects within a certain range. Due to the structural limitations of complex parts, some parts of the defects with the traditional radiographic or ultrasonic detection methods can not be detected.
? (2) Weld quality diagnosis
? The use of industrial CT scanning technology for aluminum castings porosity analysis weld quality diagnosis industrial CT device for welding quality testing, can provide accurate weld quality data for technicians, for the improvement of the welding process to provide a basis.
? (3) internal structure and assembly detection
? From the industrial CT effect, it can be clearly found in the structure of the drug sheet-like objects have broken, and can be observed through the three view direction of the internal structure, the effect is more intuitive, higher clarity, and can be accurately located defects in 3D location.
? In addition, industrial CT is also able to perform density distribution characterization and provide better metrology solutions. Industrial CT measurement technology has become an effective means of solving complex and difficult quality problems, and is suitable for most material and dimensional inspection tasks, seamlessly meeting the inspection needs of plastics engineering, aerospace, automotive, electronics, precision machinery, and scientific research and testing.
? Industrial CT looks like this: