SMD processing is inevitable testing process, SPI (Solder Paste Inspection) is the SMD processing process is a testing process, used to detect the quality of solder paste printing good or bad. Why do you need spi equipment after solder paste printing? Because the data from the industry about 60% of the soldering quality is due to poor solder paste printing (the rest may be related to the patch, reflow process).
SPI is the detection of bad solder paste printing, SMT SPI machine is located in the back of the solder paste printing machine, when the solder paste after printing a piece of pcb, through the connection of the conveyor table into the SPI testing equipment to detect its related printing quality.
SPI can detect what bad issues?
1. Whether the solder paste is even tin
SPI can detect whether the solder paste printing machine printing tin, if pcb adjacent pads even tin, it will easily lead to short circuit.
2. Paste offset
Solder paste offset means that the solder paste printing is not printed on the pcb pads (or only part of the solder paste printed on the pads), solder paste printing offset is likely to lead to empty soldering or standing monument and other poor quality
3. Detect the thickness of the solder paste
SPI detect the thickness of the solder paste, sometimes the amount of solder paste is too much, sometimes the amount of solder paste is less, this situation will cause welding soldering or empty welding
4. Detecting the flatness of the solder paste
SPI detects the flatness of the solder paste, because the solder paste printing machine will be demolded after printing, some will appear to pull the tip, when the flatness is not the same time, it is easy to cause welding quality problems.
How does SPI detect printing quality?
SPI is one of the optical detector equipment, but also through the optical and computer system algorithms to complete the principle of detection, solder paste printing, spi through the internal camera lens on the surface of the camera to extract data, and then algorithm recognition synthesized detection image, and then with the ok sample data for comparison, when compared to the ok up to the standard will be determined as a good board, when compared to the ok is not issued an alarm, technicians can be Technicians can directly remove the defective boards from the conveyor belt
Why is SPI inspection becoming more and more popular?
Just mentioned that the probability of welding bad because of solder paste printing caused by more than 60%, if not after spi test to determine bad, it will be directly behind the patch, reflow soldering process, when the completion of welding and then after aoi test found bad, on the one hand, the maintenance of the degree of trouble will be worse than the spi to determine the time of bad trouble (SPI judgment of bad printing, directly from the conveyor belt to take down, wash off the paste), on the other hand, after welding, the bad board can be used again, and after welding, the technician can directly take down the bad board from the conveyor belt. Can be utilized again), in addition to welding maintenance will cause more waste of manpower, material and financial resources.
Post time: Oct-12-2023