The function and principle of SPI solder paste inspection machine | SunzonTech


SPI is the abbreviation of Solder Paste Inspection. It is called ”锡膏检查设备“ in Chinese. This solder paste inspection machine is similar to the AOI (Auto Optical Inspection) machine that we usually usually set behind the SMT reflow oven. It also uses optical images to check the quality.

Pic: 3D SPI inspection sample picture

Principle: The solder paste inspection machine adds a laser device for solder paste thickness measurement, so the problem that SPI may consider is similar to the AOI. The SPI machine needs to take a good PCB as sample which come from visual inspection by operator, and then let the SPI machine take a picture of good PCB as a standard sample. Judgment is based on the image and data from the first PCB. Of course, the misjudgment rate will be high. Therefore, the parameters must be constantly modified until the misjudgment rate is reduced to a certain level. Therefore, the ability of SPI engineer is important. The solder paste inspection machine can only perform image inspection on the surface, if there is an area covered by an object, it cannot be inspected.

The solder paste inspection machine can measure the following data:

Solder paste printing volume.

Height of solder paste printing.

Solder paste printing area.

Flatness of solder paste printing.

The solder paste inspection machine can detect the following defects:

Whether the solder paste printing is shifted.

Whether the height deviation of solder paste printing.

Whether solder paste printing is bridged.

Whether the solder paste printing is defective or damaged.

SunzonTech provide SPI V850 series which is the true 3D SMT SPI machine.


Production Line

Production Line


Leave Message To SunzonTech Service Team, We Will Get Back Within 24 Hours.
Shenzhen Sunzon Technology Co., Ltd.
+86 13417069748
Building 45, Hengkeng Industrial Zone, Genzhuyuan Community, Matian Street, Guangming District, Shenzhen, China
Philippine Branch:
+63 9178891559