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Solder Paste Inspection is an SMT testing device that calculates the height of solder paste printed on a PCB by triangulation using the principle of optics. SPI is the abbreviation of [Solder Paste Inspection]. The main function of SPI is to detect the quality of solder paste printing, including volume, area, height, XY offset, shape, bridging and so on.

How to quickly and accurately detect very small solder paste, generally using PMP (Chinese translation for phase modulation contour measurement technology) and Laser (Chinese translation for laser triangulation technology) detection principle. Check the solder paste quality by solder paste inspection machine, improve the yield of SMT soldering, and check the board with poor solder paste printing.

The SPI solder paste thickness gauge is divided into a 3D SPI solder paste thickness detector and a 2D solder paste thickness gauge. In order to carry out quality control on electronic products, effective testing is required on the SMT production line. We usually use a 3D SPI solder paste thickness detector.


Use 3D SPI for the following reasons:

1. SMT2D solder paste thickness gauge can only measure the height of a certain point of solder paste. SMT3D solder paste thickness gauge can measure the solder paste height of the whole pad and reflect the true solder paste thickness. In addition to calculating the height, the area and volume of the solder paste can also be calculated.

2. SMT2D solder paste thickness gauge is manual focus, that the error is large.

The solder paste inspection machine can measure the following data:

●Solder paste printing.
●The height of solder paste printing.
●The area/volume of solder paste printing.
●The flatness of solder paste printing.
●Make SPC statistics to measure process capability.

In addition, the solder paste inspection machine can detect the following defects:

●Whether the solder paste printing is shifted.
●Whether the solder paste printing is highly shifted (solder projection).
●Whether solder paste printing is bridged.
●Whether the solder paste is damaged or not.


Benefits of using SPI:

1. Control the bad cause of solder paste printing, improve the printing quality of SMT solder paste, and improve the yield!

The PCB board is placed in front of the reflow oven to detect defects caused by various reasons, without having to wait until the PCB has passed the reflow oven, which greatly reduces the production cost.

2. Back solder paste printing is the first process of SMT production, and many quality defects are related to the quality of solder paste printing.

Monitoring the thickness and change trend of solder paste is not only one of the key means to improve the quality and reduce the cost of repair, but also an important measure to meet the requirements of the ISO quality system for monitoring the process parameters and improve customer confidence in production quality.

3. Simple programming / easy operation / high fault coverage / reduced production costs.

4. Check the print quality of the solder paste printer. There are no defects such as solder paste offset, missing printing, multi-tin, and less tin.