PCB

PCB – Hand Soldering Precautions

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General matters

  • For all chip or direct plug-in pads, there should not be too much tin on each pad, and it should form a smooth surface but not bulge into a ball.

  • For general patch pads, the thickness of the solder paste before welding is preferably 0.12mm (that is, the thickness of the steel mesh).

  • For EP thermal pads, the amount of solder paste should be reduced by 50%.

How to solder QFN and similar packages

  1. Confirm that there is as little excess tin as possible on the PCB and QFN component pads, and use desoldering tape to clean them.

  1. Apply an appropriate amount of tin on the pads around the PCB QFN (as shown in the picture,as much as possible).

  1. Place the QFN component to the corresponding position on the PCB.

  1. Use a heat gun to heat the QFN component and its surroundings.Make sure all the solder paste is melted and the pads are well tinned.

  1. Use tweezers to press in the center of the component, trying not to cause horizontal displacement of the component. The excess tin will be squeezed out to the surroundings in the shape of balls.

  1. Use a knife tipWuxiUse a soldering iron to pick up solder balls and clean them off.

  1. at 45°WuxiScratch the edge of each side of the QFN with the blade to ensure that the tin on the sides of the QFN component is regular.

  1. Use a heat gun to heat the QFN component and its surroundings, wait for the component to automatically return to its position and align with the silk screen.don't touch.

  1. once againat 45°WuxiScratch the edge of each side of the QFN with the blade to ensure that the tin on the sides of the QFN component is regular.

How to solder 16P Type-C and similar packages

The Type-C interface contains plastic-like parts. If the welding fails once, please use a new interface. Do not disassemble and assemble the same interface multiple times.

  1. Apply tin to the non-fixed pin part of Type-C, just a thin layer.As little as possible.

  1. Place the Type-C in place and use a heat gun to solder the non-fixed pins.

  1. Place some distance behind the pinsSmall amountSolder paste (preferably less than the picture, if there is enough at the beginning, no need to add).

  1. useWuxiThe bladed soldering iron cuts through the solder paste and non-fixed pins.

  1. Repeat steps 3 to 4 a few times until the following results are achieved (measure adjacent pins without short circuit).

  1. 从On the back, pour solder paste into the fixed pins, welding fixed pins.

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