What method is used to solder double-sided circuit boards? What matters need our attention?

With the development of high technology, people need electronic products with high performance, small size and multiple functions, which promotes the development of printed circuit board manufacturing to be lighter, thinner, shorter and smaller. There are electronic components on both sides of a double-sided circuit board, which is more compact and lighter than a single-sided circuit board, and is easy to carry. So, what is the manual soldering method for double-sided circuit boards? What are the precautions for welding double-sided circuit boards?

The soldering of electronic components mainly uses tin soldering technology. Tin-based tin alloy materials are used as solder. The solder melts at a certain temperature, and the metal solder and tin atoms attract, diffuse, and combine to form a wet bond layer. The appearance of the printed board copper platinum and the component leads are very smooth. In fact, their surfaces have many tiny bumps and gaps. The molten tin solder spreads along the surface of the soldering part by means of capillary suction, forming the infiltration of the solder and the soldering part. The components and the printed board are firmly bonded together, with good electrical conductivity.

Manual soldering method for double-sided circuit boards: According to drawings or prototypes for devices that require reshaping, get a rough understanding of the physical circuit and the direction of the device before inserting.

1. After shaping, the model side of the diode should face up, and there should be no discrepancies in the length of the two pins.

2. When inserting devices with polarity requirements, pay attention to their polarity not to be reversed. After inserting, roll integrated block components, no matter it is a vertical or horizontal device, there must be no obvious tilt.

3. Clean the rosin and soldering oil on the surface of the circuit board with absolute alcohol. When cleaning, if you use a soldering iron with heating, the speed will be faster and the effect will be better.

4. The power of the electric soldering iron used for double-sided circuit board welding is between 25 and 40W. The temperature of the electric soldering iron tip should be controlled at about 242°C. If the temperature is too high, the tip is easy to “die”, and if the temperature is too low, the solder cannot be melted.

5. Formal welding should be performed according to the welding sequence of the device from short to high and from inside to outside. The welding time must be mastered. If the time is too long, the device will be burnt, and the copper line on the copper clad board will also be burnt.

6. Because it is double-sided soldering, in order not to oblique the components underneath, a process frame for placing the circuit board should be made.

7. After the circuit board is welded, a comprehensive check-in check should be carried out to check for missing insertion and soldering, check whether the welding is correct and reliable, and whether the process meets the requirements, and trim the redundant device pins on the circuit board after confirmation. , And then flow into the next process.

8. In the specific operation, the relevant process standards should also be strictly followed to ensure the welding quality of the product.

Precautions for manual soldering of double-sided circuit boards: In addition to soldering printed boards, you need to pay special attention to:

1. Generally, the internal heating type 20~35W or the temperature adjustment type should be selected, and the temperature of the soldering iron should not exceed 30O℃.

2. The choice of the shape of the soldering iron tip is also very important. A chisel or cone-shaped soldering iron tip should be used according to the size of the printed board pad.

3. When heating the component pins, try to make the soldering iron head contact the copper foil on the printed board at the same time. When soldering larger soldering pads, the soldering iron head can be moved around the soldering pad to avoid long-term heating of the soldering pad at a certain point. Local overheating.

4. When soldering the metallized holes on the double-layer circuit board, not only the solder must wet the pads, but also the holes must be wetted and filled.

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