In the design of wave soldering, lead-free wave soldering plug component pads, pad size size design should be appropriate. The pad is too large, the solder spread area is larger, the formation of the solder joint is not full, and smaller pad copper surface tension is too small, the formation of the solder joint is not wetting solder joints. Hole and component lead with the gap is too large, easy Weld, when the aperture width than the lead 0.05 ~ 0.2mm, the diameter of the pad 2 to 2.5 times the aperture, the welding is the ideal conditions.

In the design of wave soldering, lead-free wave soldering chip component pads, should consider the following points:

1, In order to remove the "shadow effect" as much as possible, SMD solder terminal or pin should be in the direction of the tin flow to facilitate the contact with the tin stream to reduce the Weld and leak welding, wave soldering recommended component placement Map

2, wave soldering is not suitable for fine pitch QFP, PLCC, BGA and small pitch SOP device soldering, that is to say in wave soldering this side try not to arrange such components;

3, the smaller components should not be arranged in the larger components, so as not to obstruct the larger components of the tin stream with the smaller components of the pad contact, resulting in leak welding.

Wave soldering requirements of the flatness of the printed board is high, the general requirements of warpage less than 0.5mm, if greater than 0.5mm to be smoothing. In particular, some PCB thickness of only 1.5mm or so, its warpage requirements even higher, otherwise it can not guarantee the welding quality.

Save PCBs and components properly to minimize storage cycles. In welding, no dust, grease, oxides of copper foil and lead components conducive to the formation of qualified solder joints, the printed circuit board and components should be stored in a dry, clean environment, and to minimize storage cycles. Printed board for a longer time to be placed, the surface to be generally done cleaning, which can improve solderability, reduce the virtual welding and bridging, the surface of a certain degree of oxidation of the component pins, the surface oxide layer should be removed.