PCBA Processing Manual Visual Inspection has a very important role

Now in the PCBA processing process manual visual inspection is mainly through the naked eye or by virtue of some relatively simple optical magnification instruments, PCB solder paste printing and solder joints for manual visual inspection, which is a low investment and effective method, on the process of lower requirements, equipment and testing equipment is not perfect manufacturers, manual visual inspection on improving the quality of assembled products play an important role.

Artificial visual inspection includes: printed PCB manual view, glue point manual visual inspection, soldering point manual visual inspection and printed PCB surface quality visual inspection and so on.

Artificial visual inspection is the first thing that needs to be done after the completion of solder paste printing, component placement and welding. The main test content has the following two:

A. Solder Paste Printing. 

First check the parameters of the solder paste printing machine is set correctly, PCB solder paste are printed on the pad, the height of the paste is common or present "trapezoidal" shape, the edge of the paste should not be rounded or collapsed into a pile of shapes, but allows for some of the steel plate detached from a small amount of paste pulled up by the peak shape caused by the shape of the paste if the paste is not uniformly distributed, then the scraper needs to be tested. Then you need to test the scraper on the paste, whether the lack of or uneven distribution, but also need to check the printing plate and other parameters. most end up under the microscope to see whether the paste is bright after printing.

B. Component Placement. 

The list of the first PCB has been on the solder paste began to place components before printing to confirm that the material is placed on the shelf is stable, whether the components are correct and correct location of the machine to pick up the material is correct. After the completion of the first PCB, check in detail, each component is correctly placed and lightly pressed in the center of the solder paste, rather than just "put" on top of the solder paste. If you can see a slight depression in the solder paste under the microscope, it indicates that the placement is correct. Whether all the components on the data list are the same as those on the PCB, and whether all the components sensitive to positive and negative poles, such as diodes, tantalum electrolytic capacitors and ICs, are placed in the correct direction.