Analysisof white spots or spots in PCBA patch processing

Inthe production process of PCBA patch processing, there are some processingdefects occasionally. One of them is the white spot or day shift on PCBA. ForPCBA quality inspection, this problem needs to be solved. What is the reasonfor this phenomenon? How to solve it?

Causes:

1.The circuit board is subjected to improper thermal stress;

2.Due to the impact of improper mechanical force, the local resin and glass fiberare separated, resulting in the formation of white spots;

3.Some PCBA processing instruments were infiltrated by fluorine-containingchemicals and etched glass fiber cloth to form regular white spots.

resolvent:

1.Strictly control the parameters of hot air rectification, infrared hot meltingand other processing links;

2.In order to reduce the external force of the machine, measures should be takento reduce or reduce the excessive vibration of the machine during theprocessing of PCBA patch.

3.In the case of tin lead alloy electroplating, this kind of poor processingphenomenon is easy to appear between the gold-plated plug and the plug, so weshould pay attention to the selection of appropriate Tin Lead and controloperation process.