Automated Optical Inspection for PCB Quality at Venture
Years of Experience
Venture implements automated optical inspection to check high-volume, complex PCBs. It’s faster than manual inspection, more reliable, and highly repeatable.
What is Automated Optical Inspection?
Automated optical inspection is a non-contact quality control method that uses optics to detect PCB problems. It’s also commonly abbreviated as AOI. AOI automates PCB inspection, offering increased precision and reliability, fast inspection speeds, and enhanced flexibility. Manufacturers use AOI to ensure printed circuit boards meet required standards, usually by comparing them to a perfect board using imaging technology.
AOI systems are either 2D or 3D. A manufacturer may use either inspection method, depending on the PCB type and the required level of inspection.
2D Automated Optical Inspection
In this AOI type, high-resolution 2D cameras scan the board, capturing a colored image of its surface. An algorithm matches it against a master board to identify defective areas or parts. 2D systems offer faster inspection speeds. They are also cost-effective. However, their inspection scope is limited. They cannot check co-planarity issues, for instance. To check smaller, complex boards with leaded devices, manufacturers turn to 3D systems. These detect more flaws than 2D, despite increasing the inspection cost.
3D Automated Optical Inspection
3D AOI employs specialized cameras to obtain a three-dimensional image of the PCB. Although slower and more expensive, it provides more details, visualizing various features such as component shape and height. Hidden flaws, such as lifted leads of SMT components, are easily detected, increasing precision and allowing manufacturers to check small or crowded boards with hundreds of tiny parts.
Types of Defects that AOI Inspection Can Detect
An automated optical inspection machine can detect PCB defects before and after reflow or SMT placement. These include soldering errors, component problems, and board surface defects.
- Excess solder
- Inadequate solder
- Solder balls
- Missing components
- Wrongly placed components
- Shifted components
- Misaligned components
- Bent or lifted leads
- Damaged components
- Incorrect part values
- Presence of foreign objects
How Venture Conducts PCB Automated Optical Inspectionl
Venture uses advanced automated optical inspection systems to ensure the production of high-quality PCBs and PCB assemblies. These consist of optics to scan boards, special software to process captured images, and screens to display results.
PCB Optical Inspection equipment
- An operator loads the PCB onto the AOI machine
- Filtered light sources scan the PCB surface from different angles
- An optical system captures the PCB image and sends it to a sensor
- This is the AOI camera, which can be a 2D or 3D type
- The sensor converters the light image into digital data
Automated Optical Inspection Software
- AOI software processes the image data, comparing it against preloaded data sets
- The AOI system relays this feedback on a screen, and the operator can view the inspection results in real-time
- Defects, if any, are automatically identified by the system
- Defective boards are taken back for reworking
What is the Role of AOI in PCB Manufacturing?
In high production runs, the number of PCBs can be too large for manual inspection. Some defects may also be too minor for the human eye to detect. By automating the process, automated optical inspection allows manufacturers to quickly inspect PCBs in bulk, saving time and meeting customer deadlines. Automation also increases inspection accuracy, catching problems that humans would likely miss while ensuring consistency in the checking process. With AOI, PCB and PCBA manufacturers can avoid costs that flawed boards would cause. That is in addition to increasing production by enhancing inspection speeds and reducing false call rates.
Visual PCB Inspection vs. AOI PCB Inspection
Automated PCB inspection offers more benefits than visual inspection and is one of the most effective quality control methods. The table below compares the two methods side by side.
Automated Optical Inspection
Manual Visual Inspection
Proper AOI prevents defective PCBs from moving on to the next stage of their production process or even leaving the production line.
At Venture, automated optical inspection is one of the many technologies we use to check printed circuit boards during manufacturing and after. Others include various tests such as in-circuit testing, X-ray inspection, and more.
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