With the development of the precision and stability of SMT equipment, the manufacturing process and testing links have gradually become the key to the development of the industry. At the same time, the fierce competition in the consumer electronics market has put forward higher requirements for the quality of electronic components. In the production process, it is necessary to use various testing technologies to inspect defects and faults in time and repair them, among these testing technologies, X-ray inspection is one of the most critical process to improve the SMT BGA QFN soldering quality.
According to different testing methods, SMT testing technology is divided into non-contact testing and contact testing. Non-contact testing has developed from manual visual inspection to automatic optical inspection (AOI) and automatic AXI X-ray inspection , while contact testing can be divided into two categories: online testing and functional testing.
AOI (Automatic Optical Inspection) technology is introduced into the testing field of SMT production line. AOI can not only check the soldering quality, but also check the bare board, solder paste printing quality, patch quality, etc. The emergence of AOI in each process almost completely replaces manual operations, which has a great effect on improving product quality and production efficiency.
But the AOI system cannot detect circuit errors, nor can it detect what is going on inside. AXI (Automated X-Ray Inspection) automatic X-ray inspection is used as a new type of testing technology. X-rays can penetrate substances and find defects in substances, which can fully reflect the welding quality of solder joints, including open circuits, short circuits, holes, holes, internal bubbles and insufficient tin, and can be quantitatively analyzed. The biggest characteristic of X-ray inspection can penetrate the performance of the surface of the object, see through the inside of the solder joint, and can detect bridges, open circuits, solder ball loss, displacement, insufficient brazing, voids, solder balls, solder joint edge blur, etc. Solder joint defects, so as to detect and analyze the welding quality of various common solder joints.
At present, AXI technology has developed from 2D inspection method to 3D inspection method. The former is a transmission X-ray inspection method that can produce clear images for component solder joints on a single panel, but for widely used double-sided mounted circuit boards, the effect will be poor, making it difficult to distinguish the videos of the solder joints on both sides. The 3D inspection method uses layering technology to focus the beam on any layer and project the corresponding image to the receiving surface rotating at high speed. Since the high-speed rotation of the receiving surface makes the image on the focal point very clear, while the images on other layers are eliminated, the 3D inspection method can independently image the solder joints on both sides of the circuit board.
Judging from the development trend in recent years, the main basis for the selection of test technology methods should focus on the type of SMT production line components and processes, the failure probability spectrum and the requirements for product reliability. Complementing each other is the best way.
X-ray inspection machines used in the electronics industry have become an increasingly important part of the production process. With the ability to detect contaminants, defects and other non-conformities in products, X-ray inspection machines are increasingly seen as an important screening tool for risk management and quality control.
Contact Person: Mr. James Lee