1. Vector imaging technology is an advanced graphic location search method that enhances the accuracy, speed, and reliability of component recognition and positioning during the PCB assembly process. This technology can be seamlessly integrated into dedicated production environments. For PCBA OEM manufacturers and electronic manufacturing service (EMS) providers, the focus lies in enhancing component inspection capabilities while reducing overall manufacturing costs.
2. In the hardware maintenance of various electronic devices, inspecting common components on circuit boards is essential for learners in electronic maintenance. As the density of modern circuit boards continues to increase and component packaging becomes more compact, traditional inspection methods are no longer sufficient for high-speed production, leading to the development of new vector inspection techniques. In the PCB assembly process, vector imaging technology is employed to identify and place components, significantly improving the accuracy, speed, and reliability of inspections.
3. The performance of equipment on the PCB assembly production line varies based on specific requirements. The combined effects of manufacturer production demands, increased circuit board density, complex layout technologies, and smaller components create significant challenges in processes such as solder paste application, component placement, reflow soldering, and inspection.
The increase in output and the reduction in packaging have heightened the challenges of detection, causing current detection and analysis methods to lag behind the industry’s evolving needs. In recent years, various inspection methods for printed circuit board (PCB) assembly have been developed, including X-ray inspection, laser scanning, automatic optical inspection (AOI), and hybrid X-ray/AOI inspection. Among these, only AOI possesses online inspection capabilities, while others are limited in scope; for instance, laser scanning is primarily used for solder paste inspection, and two-dimensional or three-dimensional X-ray methods are employed to detect the interconnection of solder balls in area array devices.
The fundamental principle of automatic optical inspection involves using software tools that enable operators to locate and identify components. This method can detect leaded devices, chip scale packages (CSP), and ball grid array (BGA) packages. Traditional AOI relies on analyzing pixel grid values to confirm component locations on the circuit board, a method often referred to as gray-scale correlation. It compares the gray-scale reference image of a component with the actual components on the board. The image processing system searches for an exact match by counting pixels, thus identifying the component’s position. Since the system continually detects new components, reference images may frequently change to accommodate these new shapes.
When a PCB component is rotated or when its size is inconsistent with the reference model, pixel grid analysis can encounter difficulties. Similarly, variations in color, lighting, and background can complicate the matching process.
**Vector Imaging Technology**
Vector imaging technology employs composite images as teaching reference models to prevent errors. Unlike pixel analysis, vector imaging relies on the intersection vectors that define component shapes, determined by direction and inclination. In this technology, a square is represented by four line segments, while a football is depicted as two arcs.
Vector imaging technology utilizes a Windows operating system and a high-resolution digital camera. The system integrates statistical process control (SPC) software along with a comprehensive graphic library based on the components assembled on the circuit board that require inspection, measurement, and analysis. It can convert Gerber, CAD, or ASCII/Centrid data into machine code.
To achieve optimal contrast and imaging clarity, multiple light sources are employed. The program selects the light source, color combinations, and light intensity during inspection to enhance visual effectiveness. To ensure accurate recognition, the component height must be less than 8mm (measured from the PCB surface to the component’s top).
Since vector imaging technology relies on geometric information, it remains unaffected by component rotation, and the dimensions of the captured figure are consistent with the reference model, independent of changes in product color, lighting, and background. The vector imaging inspection process consists of three parts:
1. The vector imaging system identifies and isolates the main features on the component image map, measuring characteristics such as shape, size, angle, radian, and brightness.
2. It evaluates the spatial relationship between the composite image and the main features of the component being tested.
3. Finally, regardless of the component’s rotation, size, or overall appearance relative to its background, its x, y, and θ values on the circuit board are calculated.
Unlike other inspection methods, vector imaging technology adapts to every component on the circuit board as long as a reference model exists, regardless of shape, size, or orientation. When a component model is transferred from one visual inspection device to another with a different optical system, the size of the image may vary, but the system can automatically accommodate this change.
Additionally, vector imaging technology adapts to alterations in the appearance of PCB components, including new features or obscured parts due to overlap. Traditional pixel grid systems generally struggle to analyze the positions of obscured components.
