PCBA Tech - The advantages of AOI inspection in smt processing

AOI optical automatic inspection equipment is to form an image through an optical method and then process the image and then judge the various defects of the circuit board on the PCB. Theoretically, it can judge the various defects that can be seen by any human eye, such as deviation and less. Tin, short circuit, pollution, missing parts, skew, tombstones, side standing, overturned parts, wrong parts, damaged, elevated, extreme, false soldering, empty soldering, glue overflow, tin holes, unsold pins, etc.

To put it simply, the function of AOI is to do visual inspection, mainly to inspect the defective defects on the circuit board. The light source is matched with the camera to take pictures, and the source processes the taken images and uses algorithms to detect defects.

Generally, AOI can be used in three positions of SMT production line,

solder paste inspection after printing, pre-furnace inspection and after-furnace inspection for missing parts, question offset, short circuit, empty soldering, wrong answer parts, extremely reversed, reversed white, side standing, etc. .

In the SMT patch processing industry, AOI inspection is indispensable, so what is AOI inspection?

1. The principle of AOI detection

Principle: Use the optical principle to scan the PCB with the camera on the equipment, collect images, and compare the collected solder joint data with the qualified data of the machine database, and after image processing, mark the PCB soldering status.

Second, the advantages of AOI testing

As some electronic products are becoming smaller and smaller, PCB circuit boards are becoming more and more sophisticated, and the difficulty of manual inspection of PCB boards is increasing. The inspection speed is slower than that of machines. Long-term inspections are also prone to eye fatigue and missed inspections. In order to improve work efficiency, AOI can reflect its superiority.

Two: The advantages of AOI are as follows:

1. Save manpower and reduce labor costs;

2. Increase production efficiency and increase production capacity;

3. Unified testing standards, no difference due to different line types;

4. Timely feedback and statistics of production problems;

5. Collect testing data, provide process analysis, and strengthen process capabilities;

6. Improve the rate of warehousing good products.

Third, the position of AOI inspection in the smt patch processing production line

1. Use after the placement machine: it can effectively prevent the missing, polarity, displacement, tombstone, reverse, etc. of the components.

2. Use after reflow soldering: Located at the end of the SMT production line, the inspection system can check the missing, offset, and skewed components, the correctness of the solder joints and insufficient solder paste, solder short circuits, lifted pins and all polarity defects .

Although AOI detection has a great advantage over manual inspection, AOI detection is not a panacea, and there will be technical blind spots, which will lead to misjudgment. At this time, manual judgment is required. In order to ensure the quality of the products, we have created 9 original inspection procedures and inspected each level from the expected stage to the shipment, and made every effort to eliminate defective products in the bud.