In the process of pcba assembly, the causes of solder defects are as follows:
(1) phenomenon.Solder joints are dry, incomplete, and have holes. Solder materials in plug holes and lead holes are not full. Solder materials have not climbed onto the solder pads of SMT components.
PCB preheating and welding temperature is too high, so that the solder viscosity is too low.
The hole through the hole, solder flow from the hole.
(3) poor quality metallization hole or flux into the hole.
(4) PCB climbing Angle is small, not conducive to flux exhaust.
(1) preheating temperature is 90 ~ 130 ℃, SMT components is large cap, tin wave temperature (205 + / – 5), welding time is 3 ~ 5 s.
(2) the hole diameter of the plug hole is 0.15 ~ 0.4mm larger than the straight diameter of the pin, the lower limit of the thin lead, the upper limit of the thick lead.
The size of the pad should match the diameter of the pin.
4. Set the PCB is 4 ° ~ 6 ° incline Angle.
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