AXI (Automated X-Ray Inspection) is a type of optical inspection system used to inspect PCBA.
The principle is as follows: When the assembled circuit board (PCBA) enters the machine along the guide rail, there is an X-Ray emission tube located above the circuit board, and the X-ray emitted by it passes through the circuit board and is placed below the detector , because the solder joints contain a large amount of lead that can absorb X-rays, compared with the X-rays that pass through glass fiber, copper, silicon and other materials, the X-rays irradiated on the solder joints are absorbed a lot . Moreover, the black spots produce good images, which makes the analysis of solder joints quite intuitive, so simple image analysis algorithms can automatically and reliably inspect solder joint defects.
AXI technology has evolved from the previous 2D inspection method to the 3D inspection method. The former is a transmission X-ray inspection method, which can produce a clear image of the component solder joints on a single panel, but for the widely used double-sided mounting circuit boards, the effect will be very poor, which will cause the visual images of the solder joints on both sides to overlap It is extremely difficult to distinguish. The 3D inspection method uses layered technology, that is, the beam is focused on any layer and the corresponding image is projected on a high-speed rotating receiving surface. The high-speed rotating receiving surface makes the image at the focal point very clear, while the images on other layers It is eliminated, so the 3D inspection method can independently image the solder joints on both sides of the circuit board.
AXI technology is a relatively mature test technology, and its coverage of process defects is very high, usually over 97%. In small-batch production, AXI can usually be used if products with special packaged devices are included.
