The main difference is that SPI is for quality inspection of solder printing and verification and control of printing process, while AOI buffer is for device placement and solder joint inspection.

AOI buffer is caused by various mounting and welding defects in the SMT production process, such as missing parts, tombstones, offsets, polar reverses, empty welding, short circuits, wrong parts, etc. Nowadays, electronic components are becoming more and more Small, relying on manual visual inspection, slow speed and low efficiency, AOI buffer checks for poor mounting and welding, using image comparison, under different lighting, bad will show different pictures, through the good picture and bad picture Screen comparison, you can find out the bad points, so as to carry out maintenance, the speed is fast and the efficiency is high.

SPI (solder paste inspection, also known as solder paste inspection) is the quality inspection of solder printing and the verification and control of the printing process. Its basic functions:

Identify print quality deficiencies in a timely manner. SPI can intuitively tell the user which solder paste printing is good and which is bad, and provide hints of defect types.

Through the inspection of a series of solder joints, the trend of quality change is found. SPI is to detect quality trends through a series of solder paste inspections, and to find out the potential factors causing this trend before the quality exceeds the range, such as the control parameters of the printing machine, human factors, solder paste change factors, etc. Then adjust in time to control the continued spread of the trend.