A Look Inside MacroFab's AOI Inspection Process

At MacroFab, we prioritize delivering top-quality printed circuit board assemblies (PCBAs) to our clients. A vital step in achieving this is Automated Optical Inspection, also known as AOI. This article dives into AOI, explaining its role in ensuring your PCBAs meet the highest standards.

Imagine a machine with multiple high-resolution cameras, acting like a tireless inspector meticulously examining your PCB assemblies. This is the essence of Automated Optical Inspection (AOI).

AOI is a non-contact, automated visual inspection system that utilizes advanced cameras and lighting to thoroughly evaluate the quality of manufactured products. In the electronics industry, AOI plays a critical role in identifying defects and ensuring that PCBs meet the highest quality standards.

During an AOI inspection, the system typically uses multiple cameras and strategically positioned lighting sources to illuminate the PCB from various angles. These cameras capture high-resolution images or videos, creating a comprehensive picture for in-depth assessment.
Taking quality control to the next level, some AOI systems leverage Computer-Aided Design (CAD) data as a reference to identify defects in real time. This allows the machine to compare the captured image with a digital representation of a perfect board. Using image recognition, the system can verify if the correct components are present and positioned accurately.
Additionally, AOI can incorporate Optical Character Recognition (OCR) technology to read component markings and confirm they match the Bill of Materials (BOM) specifications. By employing these advanced techniques, AOI ensures a thorough and efficient inspection process.

AOI machines and technicians are adept at detecting a wide range of potential issues, including:

• Missing components
• Incorrect components
• Misaligned components
• Improper soldering (e.g., solder bridges, solder shorts, insufficient solder)
• Polarity errors
• Tombstone components (components that stand upright instead of laying flat)

MacroFab utilizes two industry-leading AOI machines from MirTech: the MV-3 OMNI and the MV-6 OMNI. Both have strong features to ensure a thorough examination of your PCBAs.

• High-Resolution Cameras: Our AOI machines feature exceptional detail, offering very low pixel resolutions (a few microns). This allows for precise examination of even the smallest components.

• 3D Inspection Technology: MV-3 and MV-6 OMNI go beyond the surface with 3D inspection capabilities. Using advanced technologies like Tri-Frequency Moiré, these machines can detect defects on components with complex geometries.

• Multi-Angle Inspection: In addition to top-down inspection, some of our AOI machines incorporate side-mounted cameras for a more complete view of your PCB assembly. This ensures that no hidden defects escape detection.

• Advanced Software: Powerful software is the core of our AOI machines. These programs intelligently compare your PCB to its design data, identify anomalies, and even learn from past inspections to continuously improve accuracy.

MacroFab's AOI technicians are quality control experts. They manage the AOI machines, ensuring proper calibration and programming for your specific PCB design. When the AOI machine flags a potential defect, the technician reviews the issue and determines if it's a genuine defect or a false alarm. If it's a defect, they take corrective action immediately.

The AOI process catches potential problems early, reducing the need for rework and saving time and materials. Since AOI can detect defects at different production stages, it can catch problems early before they cause further issues.

You might be curious about the difference between AOI and Automated Visual Inspection (AVI), another common term in manufacturing. AVI is a broader term encompassing both manual visual inspection by humans and machine inspection. AOI, on the other hand, specifically refers to automated inspection using cameras and software.

MacroFab’s investment in AOI technology offers several advantages for our customers:

• Improved Quality: AOI’s ability to catch even minor defects helps to ensure that your PCBAs function correctly and reliably.

• Reduced Costs: By catching errors early in the production process, AOI helps to prevent costly rework and scrap.

• Faster Time-to-Market: By streamlining the inspection process, AOI can help get your product to market faster.

MacroFab’s AOI technology is a key part of our commitment to delivering top-notch PCBAs. By using advanced AOI machines like the MV-3 and MV-6 OMNI, we can guarantee that your boards meet the highest quality standards, giving you peace of mind and a reliable product. If you have any further questions about AOI or our other manufacturing processes, please don’t hesitate to contact us!