Automated optical inspection (AOI) is an important inspection in printed circuit board (PCB) manufacture process. The camera of AOI scans the test PCB for both catastrophic failure (e.g. missing component) and quality defects (e.g. fillet size or shape or component skew). It is applied mainly in 3 stages of the manufacturing process: bare board inspection, pre-reflow and post-reflow. Howe choose automated optical inspection AOI is an important question for company.
There are tens of automated optical inspection manufactures in the world. They have released hundreds of automated optical inspection products with different model to market. Normally, we are not sure which one to choose when we need an automated optical inspection.
Here, we will give you some advises to help choose a suitable AOI for your PCB line.
1.Resolution in Choose a Automated Optical Inspection AOI
0201 <=15 μm
0402 <=25 μm
2. Test PCB Size in Choose a Automated Optical Inspection AOI
Every automated optical inspection have the largest PCB size it can test. Before you choose AOI, make sure that the size of PCB pads you will test is smaller than AOI’s largest test size.
3.Online AOI or Offline AOI
In the case of sufficient budget, we recommend online AOI.
- Reason A: The inspection process is almost done in sync with production. From raw materials to inspection, fully automated process production process. Reduced production time.
- Reason B: Reduced the intermediate links and reduced the input of manpower and material resources. It also reduces the error link in the middle turn.
- Reason C: From the component patch to monitor the welding quality, from the source to focus on the improvement of defective products and product scrap rate, effectively reduce the number of waste.
However, if you have limited budget, offline AOI is also a better choice than check PCB by human eyes.
4. Special features in Choose a Automated Optical Inspection AOI
If you want to test the PCBA of a multi-connected board, you must choose an AOI detector with a springboard function, that is, an AOI detector with a zone selection function. If you use the AOI detector as a quality process control, then you must choose an AOI detector with RPC capability when selecting an AOI detector, or an AOI detector with real-time process control.
5.CAD in Choose a Automated Optical Inspection AOI
Most AOI detectors now have a CAD data import function, but the use of this function is not very efficient for PCBA boards with fewer devices. The more devices on PCBA boards, the more efficient we can get.
6. SPC selection
SPC is process statistics control. Statistical control does not have real-time process control. RPC important RPC can not only perform real-time statistical analysis but also provide early warning so that the production line can maintain normal working conditions for a long time.
7. Choice of repeat ability, false positive rate and missed rate
The higher the repeat ability, the more stable the performance of the AOI detector. The lower the false positive rate, and the lower the missed rate.
In conclusion, we should choose a Automated optical inspection (AOI) based on Resolution, Test PCB Size, Online AOI or Offline AOI, SPC selection and so on. It is important to choose a suitable and cost-effective automated optical inspection. ZhenHuaXing Provide a series AOI for your requirements. please see VCTA AOI.
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