AOI technology applied in SMT processing and its development
In SMT’s AOI technology, the pattern recognition method has become the mainstream of application. This is because there are many specifications and types of surface mount components, PCB circuits, solder paste printing patterns, and assembled components among the main inspection objects of SMT’s AOI technology, and the development and changes are rapid, and the corresponding design rules , Standards are difficult to fully keep up. For this reason, the DRC method based on design rules is more difficult to apply. The rapid development of computer technology has solved the difficult problem of high-speed graphics processing and made the graphics recognition method more practical. At present, the application of various AOI technologies in SMT is becoming wider and wider.
(1) AOI products are rich and colorful
As the application technology of AOI in SMT becomes more and more mature, the competition in the AOI equipment market is becoming increasingly fierce. At present, not only are some traditional well-known AOI manufacturers competing in this field, but also suppliers of automatic test equipment that originally only produced electrical performance tests, such as Teradyne and Agilent, have also joined this field. market. For this reason, more and more types of AOI products are used in SMT, and their performance and functions are constantly improving. The following are part of SMA post-weld inspection equipment.
The HP BV3000 model launched by Hewlett-Packard (l>) of the United States can quickly detect the center line misalignment, missing components and various defects in the solder joints that exist on the general SMA. It uses fiber optic lighting that can be protected from ambient light, and its CCD camera uses a telecentric lens to reduce the impact of parallax. A combination of fiber optic lighting, CCD cameras and efficient component defect algorithms can provide reliable defect detection.
The 5539 series AOI launched by Teradyne in the United States has a vertical and four diagonal cameras, forming a precise hemispherical dome lighting system with 400 LEDs arranged. This series of equipment can have different levels of magnification to adapt to the detection data of through holes, component types and fault types, and these statistical data can be reported at any time. The company’s Optima 7300 is said to be the fastest online automatic optical inspection equipment after reflow on the market. The equipment uses a new high-speed X-Y positioning mechanism and image acquisition system, making image scanning, data processing and SMA transmission process in one go.
The RTI-6500 A0I equipment launched by American CR Company uses four high-resolution cameras to inspect solder joints and inspect the installation of components. It can detect SMA components as small as 0402 at an observation speed of 800 devices per minute, and can quickly and accurately detect large SMA components as large as 457mmX 508mm in size.
A kind of AOI equipment called Automated Inspection and Test Workstation (AIMS) launched by the American IRSI company. It is composed of SMA conveyor belt device, LED lighting system, camera with telecentric lens, calculation tool designed according to standard mode, and adapted to it It is composed of knowledge base software and control software. AIMS can detect 25 devices per second, which means that an SMA with 1000 components can be tested within 40 seconds.
Agilent has launched a more complete series of AOI equipment, including SJ series for optical inspection before and after reflow soldering, SP series for solder paste optical inspection, FX series for flux inspection, and micro-via (Micro-via) VIA series.
The InSpire-9000 series launched by Orbotech, whose main product is AOI equipment, integrates first-class optical inspection technology, including true color image acquisition technology for identifying devices and material media, and fully automatic technology without manual labor. , Image automatic recognition algorithm and modular series of architecture schemes, etc. Orbotech’s other products include RS-4L, Vision-300AP, SK-75 and PC-Micro II.
(2) AOI technology is developing towards intelligence
The development of AOI technology towards intelligence is the inevitable trend of SMT development. This is due to the large and complex detection information under the development characteristics of SMT’s miniaturization, high density, rapid assembly, and variety diversification. Whether it is in terms of real-time detection feedback, or in terms of the accuracy of analysis and diagnosis, It is almost impossible to rely on manual analysis and diagnosis of the quality information obtained by AOI. For this reason, intelligent AOI technology that replaces manual analysis and diagnosis has become an inevitable development.