Solder Paste

Solder paste printing is an important step of surface mount technology (SMT). The final result of the assembly greatly depends on the quality of this operation. For optical inspection of solder paste Phiplastic system can use one of two methods:

  • comparison of board with paste, standard board without paste and vectorial paste standard (Match + Gold or Match + Inspection);
  • direct comparison of board with paste and standard board with paste (Match).

We recommend using the first method, because it provides greater accuracy and ergonomics, and does not require a standard board with paste, i.e. can be used for initial setup of paste printer. In the first method use of Color is recommended for improving image quality of solder paste.

Digital camera or specialized device can be used to obtain images on this stage.

Board without paste
Board with paste

Thanks to Phiplastic built-in geometric calibration the paste image exactly coincides with the vectorial paste standard, imported from a CAD/CAM-system. The shortage and excess of the paste are clearly visible in the superposing layer. In addition, Phiplastic automates the search for differences.

Difference layer
Superposing layer

There are no violations of the tolerances at the fragment above. But here is defect found by Phiplastic system on this board:

Paste defect in the superposing layer
Paste defect in the object layer

See also: other stages of PCB assembly, which use Phiplastic systems.