The methods of unbroken joining of several relatively small metal parts by heating, using additional molten metal playing the role of a connector for them, are called soldering. These methods of obtaining monolithic contact of metals on the basis of processing (the use of temperature effects on the joined parts using a bonding metal) are somewhat similar to welding, but are based on completely different principles.
Soldering is the connection of several elements by heating.
The soldering process consists in applying a bonding material - solder - to the surface of each part prepared for joining, by thermal treatment of these parts with molten solder.
Then, the treated surfaces are also fused together with the addition of solder - soldered to each other with the addition of solder.
As a rule, methods of joining materials by the soldering method are used where, with a small contact area, a very high-quality connection is required that withstands mechanical and temperature loads. The most widely used soldering received in the areas of production, working with electrical and electronic circuits.
Copper soldering technology
Materials for solder.
You can talk about the use of standard soldering technology, when it is planned to inextricably connect metals, the surface of which is fairly easy, without additional tricks, can be covered with appropriate solder. Such materials include copper, brass, bronze. Steel and aluminum are much worse soldered, and with the use of specific additional technological methods and special materials. The soldering of such metals is used in special cases when it is impossible to achieve the necessary contact in other situations in other situations.
Technological elements used in the process of soldering are the following devices, devices and materials:
- electric soldering iron;
- stand for soldering iron;
- solder flux.
The following tools and materials can be used to perform preparatory and assembly operations during the soldering process:
- metal tweezers;
- side cutters (side cutters);
- assembly knife;
- emery sandpaper, fine-grained.
The device is an electric soldering iron.
Electric soldering iron - a device for the production of soldering by means of a molten solder transported on the “sting” of a soldering iron. The specified solder “sting” of the device is applied to the places and areas of the spliced objects, materials, conductors. The simplest soldering iron is usually built on the basis of a metal tubular frame, one end of which ends in a handle made of a material with low thermal conductivity (most often of wood or plastic). A soldering rod is inserted into the opposite end of the frame, which ends in a “tip”.
The heating temperature of the rod provides a spiral of refractory wire, which is wound around the tube frame and connects its ends with an electric supply wire, suitable to it through the handle of the device. The surface of the heating coil from direct contact protects the metal sheath. Depending on the temperature, which is necessary in each case for heating the brazed surfaces, appropriate soldering irons are selected that are suitable for the power and size of the soldering rod. Such devices are manufactured with a working capacity of 20 W and above, and their supply voltage can be from 6 to 220 V.Back to table of contents
The organization of the workplace for the production of soldering
For your safety, a heated soldering iron must be put on a special stand.
Taking into account the fact that a working soldering iron is a device, most of the surface of which can reach temperatures above 200º С, caused by connecting to a power source, it should be placed on a free flat plane at a point that prevents accidental contact or tilting of the device. For safe storage of the included soldering iron, it is recommended to place it on a special stand, which, in addition to the main function, can play the role of storage of flux and solder.Back to table of contents
Tinning and soldering conductors
As a rule, the metal surface is covered with an oxide film, which makes it difficult to apply the necessary solder layer on this surface. Technological technique, which still allows to treat the desired surface with solder (in other words, to tin), is the cleaning of the surface with a sandpaper or knife blade and its subsequent treatment with a special flux.
The connection of adjacent single-wire cores is twisted, followed by soldering.
For copper and other surfaces that easily accept tinning, the flux is a substance called rosin. This flux is applied to the desired point either with the “tip” of the soldering iron, if the rosin has a solid or powdered consistency, or with a small brush if an alcohol solution of rosin is used. Usually, such treatment is enough to solder with a hot "sting" evenly spread over the tinned surface of the conductor. The solder layer on the treated surface, which does not contain caverns and lumps, can serve as confirmation of the correctness of the performed tinning.
The conductors prepared in this way can be soldered, for which they should be tightly connected to each other by the tinned sections, and the surfaces to be joined should lie motionless in the same plane. Additional solder is carefully and quickly applied to the fixed conductors in such a way that the layers of tinning of the surfaces warmed by the soldering iron's tip and the applied solder turn into a homogeneous mass.
The resulting soldering must be properly cooled (only by air blowing), without violating its rigid fixation. Metal tweezers, if they hold one of the mating surfaces, can additionally serve as a heat sink element.
Properly and properly made soldering is visually a joint of two surfaces, evenly covered with a monolithic layer of solder, without sagging and dripping.Back to table of contents
Soldering of radioelements
The fundamentals of high-quality soldering are laid by a properly selected soldering iron, flux and solder.
In modern electronic equipment, a method of printed circuit boards is applied, into which radio elements are inserted, where their conclusions - “legs” - are soldered to thin foil boards of the board. This requires the use of a low-power soldering iron (up to 25 W), which has a thin “sting”.
Soldering of electronic components should be performed within a few seconds in order not to damage the heat of the “sting” of the sealed component and the foil strip of the board. For high-quality soldering of radio elements it is recommended to use solder POS 60, with a low melting point. The “legs” of the circuit elements inserted into the board and the corresponding points of the tracks should be lubricated with an alcohol solution of rosin before soldering. Solder is recommended to be applied in a circular motion "sting" around the "legs".
It should be borne in mind that high-quality soldering looks beautiful, and a sloppy drop of solder, covered with incomprehensible divorces, most likely closes the "not drunk".