Basic working principle of AOI

AOI detection process: obtain the image to be detected through the optical part; Analyze, process and judge through the image processing part. The image processing part needs strong software support, because various defects need different calculation methods to calculate and judge with computers.

Calculation method: black/white, black to white ratio, color, composition, average, sum, difference, plane and corner.

2. AOI detection process

1) AOI Intelligent Control of Light Source Changes

(1) People know that objects are judged by the amount of light reflected back. Most of the reflected amount is bright, while less is dark.

(2) AOI uses artificial light source LED light to replace natural light, and optical lens and CCD to replace human eyes. AOI compares, analyzes and judges the amount reflected from the light source with the programmed standard.

(3) For AOI, light is a key factor in understanding the MA73 - (TW) image, but the light source cannot maintain the same light source due to the influence of environmental temperature, AOI equipment internal temperature rise and other factors, so it is necessary to conduct intelligent control of light changes through "automatic tracking" of light "transmittance".

2) Solder joint detection

(1) 2D detection. Only the plane can be detected, and it needs assistance to detect the height.

(2) The top and bottom light shall be used for detection, and part of the light of the components shall be reflected to the camera, while part of the light of the solder joint shall be reflected. That is, the top light can be used to get the image of components. On the contrary, when illuminated by the bottom (horizontal) light, part of the light of the components will be reflected, and the light of the solder joint will be reflected to the camera, that is, the image of the solder joint can be obtained by using the bottom light.

3) Programming
Import programs or self compiled programs through Gerber files.

4) Character recognition

(1) The difference between AOI detection characteristics and other detection equipment.

(2) The operation process of AOI.

① First, manually test a qualified surface assembly plate as the standard plate.

② Put the standard board in AOI for scanning.

③ Program the standard board.

·Available from catalogs or customizations.

·User defined frames are used to frame components, enter component types, and set threshold, upper limit, lower limit and other information.

·As the component batches are different, and the component appearance is different from the calibrated component appearance, simple changes can be made in case of errors.

④ During continuous inspection, the machine will automatically compare with the standard plate and record the unqualified parts (mark or print them).