Basic requirements for components and printed boards of wave soldering processes

- Oct 21, 2019-

1.Requirements for SMC/SMD

Surface mount pcb metal electrode of the assembled component should have a three-layer termination structure. The component package and solder joint can withstand more than two times 260 °C ± 5 °C, 10s ± 0.5s (lead-free requirements 270 ~ 272 ° C / 10s ± 0.5s) temperature shock of wave soldering. After soldering, the component package is not damaged, cracked, discolored, deformed, and is not brittle. The chip component has no peeling (uncapping) at the end, and also ensures that the electrical performance parameters of the components after wave soldering meet the specifications book definition requirements.

2, The requirements for the inserted components

The short-insertion single-welding process is adopted, and the component leads should be exposed to the PCB soldering surface by 0.8~3mm.

 

3, The requirements for printed circuit boards

The PCB shall have a heat resistance of 260 ° C for more than 50 s (lead-free 260 ° C for more than 30 min or 288 ° C for more than 15 min, 300 ° C for more than 2 min), good resistance to copper stripping,there is still sufficient adhesion of solder mask at high temperatures, and the solder mask after soldering is not wrinkled and has no charring. Generally RF-4 epoxy fiberglass cloth printed  circuit board are used, circuit board warpage is less than 0.8% to 1.0%.

4. Requirements for pcb design

Must be designed according to the characteristics of the mounted components.

The layout of components should follow the principle of smaller components in front and avoiding mutual occlusion.


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