What is AOI
AOI （Automatic Optical Inspection or Automated Optical Inspection) is one the key tool method that used in quality inspection in the Printed Circuit board(PCB) manufacturing and PCB Assembly. It plays a big role to ensure the products are built correctly and Without manufacturing faults when leave the product line, the Inspection process of AOI are usually fast and efficiency.
Why the AOI Inspection is so much important in PCB Inspection?
The technology has been improved in every PCB manufacturing, but at the same time the requirement from end products industry like Smart watch, handheld computers, Telecommunication, 5G equipment,and advanced device like military, Aerospace also getting higher, the circuit board are in high trend to be developed to small and density. Which means the board are extremely compact, and in every related board , there are thousands of pads and solderers joint.
With so many points to be check, is impossible to inspect the faults by man(and even a very professional inspector , they can be easily get tired and lead to the incorrect construction) and usually the human work are not efficiently enough to meet the marketplace demands which required high volume ,high speed and good quality.
So a more reliable and more faster method is needed to solve the above problems, one of the best solution is to use AOI ( automatic optical machine) for inspection, the automatic inspected system can be placed in many of the process, after drilling, after plating ,image and so on, with this solution, many of the faults and defects includes Open circuts, nodules, Solder shorts, shorts Circuits stains ect can be found in early stage to avoid lost for large scale distruction of products
How AOI works
As per above information , many of the faults and defects can be check by AOI. How the AOI realize it , the answer is the visual scanning on the board surface. The inspected board is light by several Light source like fluorescent lighting , LED lighting , and then several high definition camaras are working with the light source to build up picture of the board.
After build up the picture, Several different techniques like Templating matching ,Pattern matching and Statistical pattern matching will be used to analysis the board by compare the good board that is already setting the Data on the program.
After all this process, a analyse of the board is finished and the operator will record and double check this data to process.
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