Welding process requirements and precautions for electronic components

Date：2022-01-17 16:38:00Views：2158

In the electronic industry, when electronic products are produced, the joints of components need to be welded with solder wire, and the quality of welding has a great impact on the quality of production and production. Therefore, learning electronic welding technology is the most basic and important skill in the solder industry. What are the requirements for welding process? Let's take a look at the related contents below.

1. Resistor welding

Install the resistor in the specified position according to the figure. The mark shall be upward and the word direction shall be consistent. After installing the same specification, install another specification to make the height of the resistor consistent as far as possible. After welding, cut off the redundant pins exposed on the surface of the printed circuit board.

2. Capacitor welding

Install the capacitor at the specified position according to the drawing, and note that the "+" and "-" poles of the polar capacitor shall not be connected wrongly, and the direction of the mark on the capacitor shall be easy to see. First install glass glaze capacitor, organic dielectric capacitor and porcelain capacitor, and finally install electrolytic capacitor.

3. Diode welding

Diode welding should pay attention to the following points: first, pay attention to the polarity of anode and cathode, and do not install them wrong; Second, the model mark should be easy to see and visible; Third, when welding vertical diodes, the welding time of the shortest lead shall not exceed 2S.

4. Triode welding

Pay attention to the correct insertion of E, B and C leads; The welding time shall be as short as possible. During welding, clamp the lead pin with tweezers to facilitate heat dissipation. When welding high-power triode, if it is necessary to install heat sink, the contact surface shall be flat and polished smooth before fastening. If it is required to add insulating film, do not forget to add film. When the pin needs to be connected to the circuit board, use plastic wires.

5. Integrated circuit welding

First, check whether the model and pin position meet the requirements according to the drawing requirements. When welding, first weld the two pins on the edge to position them, and then weld them one by one from left to right from top to bottom.

For capacitors, diodes and triodes exposed on the printed circuit board, the redundant pins shall be cut off.

Precautions during component welding

(1) The circuit iron used in welding shall not be charged or grounded.

After the electric soldering iron is heated, unplug the power plug or make the electric soldering iron shell well grounded to avoid induced charge breakdown of integrated circuits, especially welded MOS integrated circuits.

(2) The welding time shall not be too long.

Pay attention to the maximum temperature and maximum time when welding integrated circuits. In general, the maximum temperature and time of integrated circuit welding are 260 ℃, 10s or 350 ℃, 3S, which means that all pins of an integrated circuit are immersed at the same time, and the distance from the package base plane is 1 ~ 1.5mm. Therefore, the maximum temperature of spot welding and immersion welding should generally be controlled at about 250 ℃ and the welding time is about 7S.

(3) Pay attention to heat dissipation.

Some high-power integrated circuits have good heat dissipation conditions. When replacing the integrated circuit, the heat sink should be fixed again to make it in close contact with the integrated circuit, so as to prevent the integrated circuit from being damaged by heat. Pay attention to the following points when installing the heat sink:

① Do not weld the ground wire to the heat sink without determining whether the heat sink of the power integrated circuit should be grounded;

② The installation of heat sink shall be flat and the tightening torque shall be moderate, generally 0.4 ~ 0.6N m；

③ Before installation, the dust and rust between the heat sink and the integrated circuit shall be removed, and silicone grease shall be padded between them to reduce the thermal resistance;

④ After the heat sink is installed, it is usually welded to the grounding end of the printed circuit board with leads;

⑤ Before installing the heat dissipation plate, it is not allowed to power on at will.

The above is the related content of "electronic component welding" brought by the core detection. Through this article, I hope it can be helpful to you. If you like this article, you might as well continue to pay attention to our website, and we will bring more wonderful content later. If you have any needs related to the inspection and testing of electronic products, please call Chuangxin testing, and we will serve you wholeheartedly.