Working principle and application scope of X-ray detection

Date：2021-09-18 17:42:00Views：1881

With the continuous development of electronic technology, SMT technology is becoming more and more popular, the volume of single chip microcomputer chip is becoming smaller and smaller, and the foot position of single chip microcomputer chip is also gradually increasing, especially BGA single chip microcomputer chip appeared in recent years. Because the BGA single chip microcomputer chip is not distributed according to the traditional design, but distributed at the bottom of the single chip microcomputer chip. According to the traditional artificial vision detection, it is undoubtedly impossible to judge the quality of the solder joint, so it must be tested according to ICT and even function. However, if there are batch errors, they cannot be found and corrected in time. Artificial vision detection is the most inaccurate and reproducible technology. Therefore, X-ray detection technology is widely used in SMT post reflow detection. It can not only qualitatively analyze the solder joint, but also find and correct the fault in time.

Every industry will have some effective auxiliary tools. Now, let's talk about the X-ray testing equipment with the rapid development of the electronic industry. I believe that friends working in this industry have a certain understanding. This paper summarizes the working principle and application scope of X-ray detection device, so that you can quickly grasp it at a glance.

Working principle of X-ray detection equipment

1. First, the x-ray device mainly uses the penetration of X-rays. The wavelength of X-ray is very short and the energy is very large. When a substance irradiates an object, it will only absorb a small part of X-rays, and most of the energy of X-rays will pass through the gap of material atoms, showing strong penetration.

2. X-ray device can detect the relationship between X-ray penetration and material density, and substances with different densities can be distinguished through differential absorption. In this way, if the detected object has different thickness, shape change, X-ray absorption and image, different black-and-white images will be generated.

3. It can be used for IGBT semiconductor testing, BGA chip testing, LED light bar testing, PCB bare board testing, lithium battery testing and nondestructive testing of aluminum castings.

4. Simply put, it is to output high-quality fluoroscopy images using interference free micro focus X-ray equipment, and then convert them into signals received by flat panel detectors. All functions of the operating software are completed only with the mouse, which is convenient to use. The standard high-performance X-ray tube can detect defects less than 5 microns, while some x-ray devices can detect defects less than 2.5 microns, and the system can amplify 1000 times and tilt the object. X-ray equipment can be used for manual or automatic detection, and the detection data can be generated automatically.

X-ray Technology

X-ray technology has developed from the previous 2D detection station to the current 3D detection method. The former is projection X-ray flaw detection, which can produce a clear visual image of the solder joint on the single board, but the effect of the commonly used double-sided reflow board is poor, resulting in the overlap of the visual images of the two solder joints, which is difficult to distinguish. The latter three-dimensional detection method adopts layered technology, that is, the beam is concentrated on any layer, and the corresponding image is projected to the high-speed rotating receiving surface. Because the receiving surface tells the rotation, the image at the intersection is very clear, while the images of other layers are removed, 3D detection can image the solder joints on both sides of the board independently.

3DX ray technology can not only detect the double-sided welded plate, but also comprehensively detect the multi-layer image slices of invisible solder joints such as BGA, that is, the upper, middle and lower image slices of BGA Solder ball joint. In addition, this method can also detect the through hole of PTH solder joint and check whether the through hole solder is sufficient, which greatly improves the connection quality of solder joint.

Replacing ICT with X-ray

With the increase of layout density and the smaller and smaller volume of devices, the point space of ICT test becomes smaller and smaller when designing layout. Moreover, for complex plates, if they are directly sent from SMT production line to function test post, it will not only reduce the product qualification rate, but also increase the cost of fault diagnosis and maintenance of circuit board, even if it causes delivery delay, In today's highly competitive market, if X-ray inspection is used instead of ICT inspection, the production track of functional test can be ensured. In addition, batch inspection with X-ray in SMT production can reduce or even eliminate batch error. It is worth noting that there are too few or too many solder that cannot be measured by ICT. In addition, X-ray can also be measured, such as cold sweat, welding, pores, etc, And it is easy to detect these defects through ICT and even function detection, which affects the service life of the product. Although X-ray cannot detect the electrical defects of the equipment, these can be detected through functional test. In a word, adding X-ray detection method will not miss the defects in the manufacturing process, but also find some defects that cannot be found by ICT.

Application scope of X-ray detection device

1. Industrial X-ray testing equipment is widely used in lithium battery testing industry, circuit board industry, semiconductor packaging, automobile industry and circuit board assembly (PCBA) industry. Observe and measure the position and shape of internal objects after packaging, find problems, confirm that the products are qualified, and observe the internal conditions.

2. Specific application scope: mainly used for SMT LED. BGA. CSP flip chip detection, semiconductor, packaging components, lithium battery industry, electronic components, auto parts, photovoltaic industry, aluminum die casting, molding plastics, ceramic products and other special industries.

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