Precision PCB Fabrication, High Frequency PCB, High Speed PCB, Standard PCB, Multilayer PCB and PCB Assembly.
The most reliable PCB custom service factory.
PCBA Tech
An important part of SMT component visual inspection
PCBA Tech
An important part of SMT component visual inspection

An important part of SMT component visual inspection

2021-11-10
View:34
Author:Downs

1. The impact of foreign matter on the lens of SMT mounter, the glass lens above the aperture, its function is to prevent dust from entering the aperture, affecting the intensity of the light source, but if there is foreign matter such as dust or components on the glass lens, it will affect the intensity of the light source. Low, the gray value is low. This leads to poor recognition, so the placement machine should pay attention to the cleaning of the lens and various lenses.

     2. The influence of the reflector, the reflector acts on the backlight. When there is dust on the reflector, the intensity of the light source reflected to the camera will be reduced, and the gray value will also be reduced, resulting in poor recognition and component loss, so SMT stickers The film machine should pay attention to the reflector is a part that needs to be wiped regularly.

     3. The influence of the aperture light source, the intensity of the light source will gradually decrease after the aperture light source is used for a period of time, because the intensity of the light source is directly proportional to the gray value converted by the solid-state camera, and the larger the gray value is, the closer the digital image is to the view observed by people 

pcb board

So as the intensity of the light source decreases, the gray value also decreases, but the gray value in the machine will not decrease with the decrease of the light source intensity. Only by regular calibration and detection, the gray value will be the same as the intensity of the light source. In direct proportion, when the intensity of the light source is so weak that the component cannot be identified, the bulb needs to be replaced.

     4. Improper setting of SMT component library parameters. This is usually caused by the inconsistency of the component shape during the refueling. The identification parameters need to be re-checked and set. The inspection items include the component shape and size. The solution is to let the vision system "learn" the component shape again, and the system will generate similarities from the ground. Comprehensive description of CAD, this method is quick and effective. In addition, if the size consistency of the incoming material is not good, the tolerance can be appropriately increased.

     5. The impact of the suction nozzle. When the backlight is recognized, if the shape of the suction nozzle is larger than the contour of the device, there will be the contour of the suction nozzle in the image. The recognition system will regard the contour of the suction nozzle as part of the component, which will affect the recognition of SMT components. Centering. We can deal with specific reasons:

           a. If the outer diameter of the Yamaha nozzle is larger than the device size, switch to a nozzle with a smaller outer diameter.

           b. The position deviation of the suction nozzle causes the contour of the suction nozzle to extend to the contour of the device to adjust the deviation of the material level. HSP4796L has the function of automatically correcting the component suction position. By continuously measuring the suction position of a component, the average error is calculated and a correction value is automatically generated to compensate. The correction value is stored in Feeder (B) Offest, and in the SMT database. The correction value automatically generated for each material level can solve the problem by clearing the deviation value of the material level where the component is located.

      Through the above introduction, everyone understands that the visual inspection of SMT components is an important part of the placement machine. In order to avoid incorrect placement of materials during SMT placement, it is recommended that you must do a good job in the maintenance of the machine at ordinary times!