Can the SPI solder paste inspection machine detect defects?

Source:我的网站      Tiem:2020-12-05 17:43:00

SPI is the abbreviation of [Solder Paste Inspection], and it is called [Solder Paste Inspection] in Chinese. If it is a solder paste inspection machine, add the English word Machine at the end, but in most cases, just talk to the other party about SPI. Talking about solder paste inspection machine.


What is the use of SPI (Solder Paste Inspection)? What kind of inspection can you do for us? Why are there more and more SMT production lines with SPI devices?


About 80% of the defective rate of SMT comes from improper printing of solder paste. Then you think that a "Solder Paste Inspection (SPI)" checkpoint should be set up after solder paste printing and before parting/mounting. The board should be brushed down before the parts are printed. Can the yield rate of SMT soldering be improved? The answer should be yes, the key point is how to use the solder paste inspection machine to correctly screen out the boards with poor solder paste printing, and then go forward to track why the solder paste printing is defective.


Especially now there are more and more parts below 0201 or bottom soldering parts such as BGA, which are very sensitive to the quality of solder paste printing. If the board with solder paste printing problems can be detected before the furnace, it will It is more effective and cost-effective than detecting after the reflow soldering is completed, because the repair of the board after the furnace usually requires a soldering iron or complex repair tools, and the board may be damaged.


This kind of "solder paste inspection machine" is actually similar to the AOI (Auto Optical Inspection) optical identification system device that we usually usually place behind the SMT furnace. It also uses optical images to check the quality. The difference is that the solder paste inspection machine is added. A laser device for solder paste thickness measurement, so the problems that SPI may encounter are similar to those of AOI. First, take a piece of the jigsaw for visual inspection and then let the machine take a picture as a golden sample. The images and data of the first board are used to make judgments. Of course, there will be a lot of misjudgment rates. Therefore, the parameters must be constantly modified until the misjudgment rate is reduced to a certain level, so it is not necessary to buy the SPI machine To use, there must be an engineer who can write programs and maintain.


In addition, most solder paste inspection machines can eat Gerber and CAD, but they usually have some errors and still need to be adjusted.



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