Reasons for poor soldering of cold-pressed terminals

In the electrical wiring system, the connection between PCB terminals, such as screw terminals and circuit boards, needs to be fixed by soldering. However, in some cases, it may be due to many factors such as materials or improper operation that may cause poor soldering. occur. In view of this, some common reasons that may lead to poor soldering of terminal blocks are sorted out.
1. The tin-lead plating solution of the terminal is polluted, resulting in poor plating;
2. Excessive gloss agent, resulting in excessive carbon content of the coating;
3. Poor post-plating treatment (salt formation, foreign matter adhesion, etc.);
4. The voltage is too high during electroplating, resulting in thermal oxidation and passivation of the plated parts;
5. The current density is too high, the bath temperature is too high, etc., resulting in poor coating structure;
6. The plating layer at the soldering part of the terminal is oxidized due to poor storage environment and too long time;
7. The plating layer at the soldering part of the terminal is too thin;
8. Solder temperature is too high or too low;
9. The influence of the shape and structure of the plated parts;
10. Low purity of flux;
11. The effect of plating material (tin > tin lead > gold > copper > phosphor bronze > nickel > brass).