What is the Difference between First Article Inspection and AOI Inspection

The PCBA processing process is a very precise process, and it is more complicated and cumbersome, so there will be relatively high defects in the PCBA processing process. In order to avoid the occurrence of undesirable phenomena and improve the production efficiency of PCBA, various inspections will be carried out in the production process. first article inspection and AOI inspection are relatively common. What is the difference between them?

1. First Article Inspection

The first article inspection is done before the mass production of PCBA, and is the inspection of the first sample or the first few samples after PCBA processing. Therefore, the so-called "first piece" of the first article inspection does not specifically refer to the first product, but usually refers to the first few proofing products after the processing is completed, or it can be the inspection quantity required by the customer. If the customer does not have a requirement for the number of inspections, generally the first 3 to 5 products are inspected by default. The inspected projects include component misplacement, missing sticker, displacement, resistance and other issues, and can also inspect most of the defects except the welding quality.

The inspection principle of the first article detector is to scan the first few samples processed, import the bill of materials and patch coordinate files, and calibrate and judge the test results through the software. If the test result is OK, the product can be put into mass production; If a defect is found, it is necessary to analyze the cause and improve it. This avoids the huge loss caused by mass production in the case of quality problems, which is also the role of the first article inspection.

2. AOI Inspection

AOI inspection is generally the inspection process in the mass production stage, which belongs to the quality control method at the end of the PCBA processing process. It is mainly used to inspect the bad phenomenon of PCBA placement and welding. Its working principle is to compare the test board with the input information of the good PCBA board through the optical principle. AOI inspection can inspect defects such as excessive tin, less tin, and displacement, and can also inspect defects in solder paste printing, but the inspection effect is not as good as SPI.

To sum up, the difference between first article inspection and AOI inspection is mainly lies in different positioning and working principles, and secondly in the different application stages. First article inspection is mainly used in the proofing stage in the early processing stage, while AOI inspection is used in the final quality control stage in the mass production stage. There are also differences in the test projects. The first article detector can detect defects other than soldering quality, while AOI mainly detects defects in solder paste printing, component placement and soldering quality. For these two kinds of inspections, first article inspection is faster than AOI inspection in terms of inspection efficiency.

HoYoGo is an international, professional and reliable PCBA manufacturer, we have our own factory, advanced machines, our production strictly follows the high quality system, and passed ISO9001, ISO14001, ISO13485 and TS16949 and C-UL-S certification. All products strictly follow the acceptance criteria of IPC-A-600-H and IPC-6012, which can guarantee the quality and reliability of every product delivered to customers.