Electric soldering iron is an indispensable tool for electronic production and electrical appliance maintenance. The main purpose is to weld components and wires. According to the mechanical structure, it can be divided into internal heating electric soldering iron and external heating electric soldering iron. Tin soldering irons are divided into high-power soldering irons and low-power soldering irons according to different uses.

■Instructions

1. Choose suitable solder, low melting point solder wire for welding electronic components.

2. Flux, use 25% rosin dissolved in 75% alcohol (by weight) as flux.

3. The soldering iron should be tinned before use. The specific method is: heat the soldering iron, apply the flux when the solder is just melted, and then apply the solder evenly on the soldering iron head to make the soldering iron head eat evenly A layer of tin.

4. Welding method, polish the pad and component pins with fine sandpaper, and apply flux. Dip an appropriate amount of solder with the tip of the soldering iron and touch the solder joint. After the solder on the soldering point is completely melted and immersed in the component lead, the soldering iron tip is gently lifted away from the solder joint along the lead of the component.

5. The welding time should not be too long, otherwise the components may be easily scalded. If necessary, clamp the pins with tweezers to help dissipate heat.

6. The solder joint should be in the shape of a sine wave peak, the surface should be bright and smooth, no tin thorn, and the amount of tin is moderate.

7. After the soldering is completed, the residual flux on the circuit board should be cleaned with alcohol to prevent the carbonized flux from affecting the normal operation of the circuit.

8. The integrated circuit should be soldered last, and the electric soldering iron should be reliably grounded, or use residual heat to solder after power off. Or use a special socket for the integrated circuit, and then plug the integrated circuit after soldering the socket.

9. The electric soldering iron should be placed on the soldering iron rack.

■ Types of electric iron

Ordinary soldering iron

Old-style electric irons have a fixed heating power. The temperature of the iron tip depends on the heat dissipation speed. Large ones can only weld large parts, and small ones can only weld small parts.

Internal heating electric iron

One of the old styles is very cheap, with built-in ceramic heating core, which is safer. In the past, due to the high thermal efficiency and current saving, it became less and less

External heating electric iron

The second of the old styles, a soldering iron tip is placed in the center of the mica heating coil, the one without temperature control is also very cheap, and a high-power model can be made.

Thermostat electric iron

The characteristic of this type of electric soldering iron is the built-in temperature sensing and temperature adjustment circuit, so it can be powered off and cooled when the temperature reaches the setting, and then return to the set temperature with high power when the temperature drops. The greater the power of the thermostat electric iron, the better the performance and the more convenient, without worrying about the high-power burning components.

Constant temperature electric iron

Taiwanese and low-end Japanese products are more common. The temperature of the soldering iron is controlled within a certain temperature with ceramic temperature control elements. The performance and ordinary soldering iron ratio are very small, but the probability of burning to death is much lower.

Hand held thermostat electric iron

This electric soldering iron comes with a thermocouple inside the soldering iron core, and the temperature can be adjusted with a potentiometer. DIY is very affordable.

Thermostat soldering station

The ultimate evolutionary form of soldering irons. The heating core and soldering iron head of some soldering stations are integrated. Direct current heating is used instead of direct current heating. The safety and antistatic performance are good. The temperature adjustment circuit is more complete and accurate, and the temperature return performance is also more. Well, it can adapt to factory assembly high-intensity long-term high-standard work. It's too expensive for DIY to be cost-effective. The representative product is BEE soldering station.

■ Various soldering iron heads

The general soldering iron head is made of copper. The old soldering iron head directly exposes the copper surface, which is easy to blacken the oxide layer and not tin. It is often necessary to sand and polish the tin with sandpaper. The surface of the new-style soldering iron head has a silver anti-oxidation alloy coating, which has a much better anti-oxidation performance. Inferior soldering iron tips can be used as iron bars to impersonate copper bars, so be careful.

The shape of the soldering iron head can be divided into pointed head, horseshoe head, flat head, each of which has a size. Generally, the tip and the horseshoe head are used more when soldering the circuit, and the flat head is easier to use when there are more solder chips.

■ Tip cleaning tool

Electric soldering irons with alloy coatings cannot be hard ground, and only special cleaning tools can be used to remove the oxide layer. High temperature sponge / slag wool, wipe the tip of the iron after wetting with water. Remember to add water or it will burn out. Alloy wool, a special steel ball made of low-hardness alloy, is used to remove the oxide layer on the surface, while avoiding injury to the alloy coating. The advantage is that the temperature of the soldering iron tip does not drop after cleaning, and it receives less thermal shock.

Genuine clean steel wire balls are very expensive. Fu-80 proposes that ordinary clean steel wire balls on the market are used on a large scale in factories. Individuals expressed doubts about the damage to the iron head.

Solder and flux

    Including various tin wires, tin pens, tin bars. The melting point of lead is low, the surface is relatively smooth, and the welding feel is good. The lead-free ones are slightly difficult to use, but they are healthier. I try to use lead-free. Most tin wires come with a rosin core, and generally no flux is required.

Flux / welding oil / rosin

    I think the white acid-free soldering oil is very easy to use. The solder paste is very cheap but contains acid chloride. It must be cleaned with alcohol after use. Traditional rosin and rosin paste, heating for a long time will leave black carbonized residue. The water-based flux is said to have many advantages, but the evaporation rate is too fast when used.

Desoldering tool

Tin suction device

    To suck tin through a suction piston, it needs to be used with a soldering iron or a hot air gun.

Electric tin suction device

    With its own heating head, it can be used with one hand, which is much more convenient to use.

Electric tin suction gun

    Comes with electric heating head and air pump, no need to manually press the piston. There are desktop and portable.

Suction tape

    The thin copper wire braid coated with some flux is an artifact. It sucks very cleanly when sucking a small amount of tin, but it is a consumable. The single-use loss is larger, and it is better to use with the tin absorber. Recommended if possible. Used to remove the pads of old-style in-line components. Very little is used, all solved with suction tin tape.

■ Other tools

Soldering iron stand

     Place soldering iron, sponge, welding wire, rosin, etc.

Welding frame

     The important point is that the clip can help you fix the component and save valuable two hands. Some models have a magnifying glass and LED lights, suitable for precision welding.

Anti-static wrist strap

     Must be used when mass producing or welding static sensitive components.

Hot air gun

     If used well, it can be called an artifact, which is particularly useful for desoldering chip components. Standard equipment for many professional soldering stations. Like the soldering iron, there are bargains, and there are also advanced versions with arbitrary adjustment of temperature and air volume.

Gas soldering iron

     Relying on gas flame heating rather than electricity to provide heat, it is useful in places like the wild.

Pen battery soldering iron

     Battery power supply is also suitable for use in places without stable power supply.