What is solder solder

Soldering SMD components at home

Many people wonder how to properly solder SMD components. But before we deal with this problem, it is necessary to clarify what these elements are. Surface Mounted Devices - translated from English, this expression means surface-mounted components.

Their main advantage is their greater mounting density than conventional parts. This aspect affects the use of SMD elements in the mass production of printed circuit boards, as well as their cost-effectiveness and manufacturability of installation.

Conventional parts with wire-type leads have lost their widespread use along with the rapidly growing popularity of SMD components.

Errors and basic principles of soldering

Some craftsmen claim that soldering such elements with your own hands is very difficult and quite inconvenient. In fact, similar work with VT components is much more difficult. In general, these two types of parts are used in various fields of electronics. However, many people make certain mistakes when soldering SMD components at home.

SMD components

The main problem that hobbyists face is choosing a thin tip for a soldering iron. This is due to the existence of an opinion that when soldering with a regular soldering iron, you can stain the legs of SMD contacts with tin.

As a result, the soldering process is long and painful. Such a judgment cannot be considered correct, since in these processes the capillary effect, surface tension, and wetting force play a significant role.

Ignoring these extra tricks makes it difficult to do the DIY job.

Soldering SMD components

To properly solder SMD components, you must follow certain steps. To begin, apply the soldering iron tip to the legs of the taken element.

As a result, the temperature begins to rise and the tin begins to melt, which eventually completely flows around the leg of this component. This process is called wetting force. At the same instant, tin flows under the leg, which is explained by the capillary effect.

Along with wetting the leg, a similar action occurs on the board itself. The result is a uniformly filled bundle of boards with legs.

Contact of the solder with adjacent legs does not occur due to the fact that the tension force begins to act, forming individual drops of tin. It is obvious that the described processes occur on their own, with only a small participation of the soldering iron, who only heats the legs of the part with a soldering iron. When working with very small elements, they may stick to the soldering iron tip. To prevent this from happening, both sides are soldered separately.

Factory soldering

This process occurs on the basis of a group method. Soldering of SMD components is carried out using a special solder paste, which is evenly distributed in a thin layer onto the prepared printed circuit board, where there are already contact pads.

This application method is called silk-screen printing. The material used is similar in appearance and consistency to toothpaste. This powder consists of solder to which flux has been added and mixed.

The deposition process is performed automatically as the printed circuit board passes through the conveyor.

Factory soldering of SMD parts

Next, robots installed along the motion belt arrange all the necessary elements in the required order. As the board moves, the parts are firmly held in place due to the sufficient stickiness of the solder paste.

The next step is to heat the structure in a special furnace to a temperature slightly higher than the one at which the solder melts. As a result of such heating, the solder melts and flows around the legs of the components, and the flux evaporates.

This process makes the parts soldered into their seats. After the oven, the board is allowed to cool, and everything is ready.

Required materials and tools

In order to do the work of soldering SMD components with your own hands, you will need to have certain tools and consumables, which include the following:

• soldering iron for soldering SMD contacts;
• tweezers and side cutters;
• an awl or needle with a sharp end;
• solder;
• a magnifying glass or magnifying glass, which is necessary when working with very small parts;
• neutral liquid no-clean flux;
• a syringe with which you can apply flux;
• in the absence of the latter material, you can get by with an alcohol solution of rosin;
• To make soldering easier, craftsmen use a special soldering hair dryer.

Tweezers for installing and removing SMD components

The use of flux is absolutely necessary, and it must be liquid. In this state, this material degreases the working surface and also removes the formed oxides on the metal being soldered.

As a result, an optimal wetting force appears on the solder, and the soldering drop better retains its shape, which facilitates the entire work process and eliminates the formation of “snot.”

Using an alcohol solution of rosin will not allow you to achieve a significant result, and the resulting white coating is unlikely to be removed.

Solder for soldering

The choice of soldering iron is very important. The best tool is one that allows you to adjust the temperature.

This allows you not to worry about the possibility of damage to parts due to overheating, but this nuance does not apply to moments when you need to desolder SMD components.

Any soldered part can withstand temperatures of about 250–300 ° C, which is ensured by an adjustable soldering iron. If such a device is not available, you can use a similar tool with a power of 20 to 30 W, designed for a voltage of 12–36 V.

Using a 220 V soldering iron will not lead to the best consequences. This is due to the high heating temperature of its tip, under the influence of which the liquid flux quickly evaporates and does not allow the parts to be effectively wetted with solder.

Experts do not recommend using a soldering iron with a conical tip, since it is difficult to apply solder to parts and a lot of time is wasted. The most effective is the sting called “Microwave”. Its obvious advantage is a small hole on the cut for more convenient capture of solder in the right amount. With such a tip on the soldering iron it is convenient to collect excess solder.

Soldering iron tip “Microwave”

You can use any solder, but it is better to use a thin wire, with which you can conveniently dose the amount of material used. The part to be soldered using such a wire will be better processed due to more convenient access to it.

Work order

The soldering process, with a careful approach to theory and gaining some experience, is not difficult. So, the whole procedure can be divided into several points:

1. It is necessary to place SMD components on special pads located on the board.
2. Liquid flux is applied to the legs of the part and the component is heated using a soldering iron tip.
3. Under the influence of temperature, the contact pads and the legs of the part themselves flood.
4. After pouring, remove the soldering iron and allow time for the component to cool. When the solder has cooled, the job is done.

Soldering process for SMD components

When performing similar actions with a microcircuit, the soldering process is slightly different from the above. The technology will look like this:

1. The legs of the SMD components are installed exactly at their contact points.
2. In areas of contact pads, wetting is performed with flux.
3. To accurately place the part in the seat, you must first solder one of its outer legs, after which the component can be easily aligned.
4. Further soldering is carried out with the utmost care, and solder is applied to all legs. Excess solder is removed with a soldering iron tip.

Soldering iron with a sharp tip 24 V.

How to solder with a hair dryer?

With this soldering method, it is necessary to lubricate the seats with a special paste. Then the required part is placed on the contact pad - in addition to components, these can be resistors, transistors, capacitors, etc. For convenience, you can use tweezers.

After this, the part is heated with hot air supplied from a hair dryer, at a temperature of about 250º C. As in previous examples of soldering, the flux evaporates under the influence of temperature and the solder melts, thereby flooding the contact tracks and legs of the parts. Then the hair dryer is removed and the board begins to cool.

When it has cooled completely, soldering can be considered complete.

Hair dryer for soldering small parts

Source: https://LampaGid.ru/elektrika/komponenty/pajka-smd

How to solder correctly with a soldering iron, how to desolder a microcircuit

For professionals, the title of the article may cause a condescending smile. It would seem, what’s so complicated here? I cleaned the contacts, scooped up some solder with the nose of the soldering iron, and applied it to the connection point. For an experienced radio amateur, this process really does not cause problems. But if everyone (including professionals) knows how to solder correctly with a soldering iron, where do unsoldered boards, short circuits between adjacent contacts, and parts that fail due to overheating come from?

Our material will tell novice craftsmen how to learn to solder using traditional and non-standard methods, and for those who consider themselves professionals, it will help improve their skills.

What is soldering

Without referring to Wikipedia, we will explain in our own words. Soldering is the joining of metal contacts using a conductive melt, followed by its solidification. In this case, unlike welding, none of the parts being connected should melt during the process. Of course, after the conductive melt (solder) has solidified, reliable electrical conductivity of the connection must be ensured. Contact resistance cannot affect the characteristics of the electrical circuit.

General rules for working with a soldering iron (we will consider all these points in detail in the review)

• The connection point must be mechanically cleaned of dirt, protective coating and oxides (if the dimensions and design of the parts and conductors allow). What you can focus on: some metals, in principle, cannot be cleaned of the oxide film, at least in air. Only under a continuous layer of special fluxes (we are talking about aluminum and alloys based on it). The fact is that the “winged metal” oxidizes instantly.
• To degrease the connection point, special cleaners are used: fluxes. They should not have a destructive effect on the metal you are working with. Even if the joint seems perfectly clean, soldering without flux is almost impossible. When the heated soldering iron tip touches, thermal oxidation occurs. Important: metals used in electrical engineering (aluminum, copper, silver, gold) in their pure form have good adhesion. Standard solders seem to stick to the surface, securely fixing after hardening. The layer of oxide film not only prevents “sticking”, it is also a dielectric. And fluxes, when heated, activate their cleaning properties, and not only remove invisible contaminants, but also prevent oxidation. Special fluxes have been developed for various materials. Even acids are used.
• The shape and dimensions of the working tip of the soldering iron tip must correspond to the contacts and soldering conditions. The material does not matter: it can be copper, ceramics, or hard alloys, silver-plated.
• Choice of power - the range of 25–60 W is suitable for soldering printed circuit boards. Too high a temperature can not only overheat the soldering area, some radio components fail when exposed to heat. The other side of the coin: low temperature will be removed from the soldering zone by massive contacts or a thick heat-conducting conductor. You will have to keep the tip in the working area for a long time - hence the overheating of the parts again. For example, when the question arises of how to solder a capacitor, it is important to know exactly the degree. The golden rule of soldering: high temperature and short-term heating. This skill comes only with experience.
• Solder selection. From the point of view of adhesion, all types work well. That is, selecting contacts for a specific metal is not task No. 1. But the melting point should be treated carefully. On the one hand, low-melting compounds make it possible to minimize the thermal effect on parts. On the other hand, this creates two additional problems: Firstly, low-melting solder “unsolders off” just as quickly. If the temperature conditions of the contact connection are not very favorable, there is a possibility of loss of contact during operation. Secondly, you will definitely encounter the fact that the solder is already in a liquid state, and the contacts have not yet warmed up for normal adhesion. As a result, the soldering point again overheats.

Let us repeat, these are only theoretical principles, from which it is not yet clear how to solder with a soldering iron. You will see detailed instructions below.

Selecting a soldering iron

If you are not involved in radio work professionally (most likely this is the case, otherwise you would not have studied this material), you have in your arsenal an ordinary soldering iron in one copy. We are not talking about a soldering station at all, since it is quite expensive (albeit a very convenient kit). But for a novice master this is overkill.

Let's return to soldering irons. The classic is a nichrome heater and a copper tip. In fact, this is the best combination, but for manual control. No temperature control, smooth slow heating. At the same time, the copper tip holds the temperature perfectly, and often compensates for the heat dissipation at the soldering site. Another advantage is that the soft material allows you to mold any tip configuration. You can literally rivet and cut out a tip for a specific type of soldering.

The only drawback is that copper burns out quickly, and this type of tip is actually a consumable item. It constantly has to be sharpened with a file.

Tip: Be sure to use a hammer before shaping the tip with a file. Once the copper rod is sealed, it will last longer. A little lost time is more than compensated for by ease of use.

The illustration shows the classic “screwdriver” shape. A universal tip for most amateur jobs.

If your “heating device” is equipped with a temperature controller, you must take into account the inertness of copper. It dials the set number slowly and also slowly cools down.

The ceramic tip with silver plating is a modern accessory. If the question is how to work with SMD format parts, or how to desolder a chip from a double-sided board, this is your option. However, they are not so convenient for soldering powerful heat-intensive wires and contacts.

Such a soldering iron heats up instantly, and you can precisely control the degrees on it (if there is a regulator).

The heating method can be any. The same ceramic heater as the tip, or nichrome. Induction heaters are also used on copper soldering irons, but these are rather exotic.

How to desolder a microcircuit with a soldering iron

By picking up the microcircuit with a screwdriver and applying slight pressure on it, while simultaneously warming up the legs of the microcircuit located on one side with a soldering iron, you can gradually desolder it. How to do this is shown in more detail in the video at the bottom of the article (watch starting at 15 minutes 15 seconds).

How to solder or desolder a microcircuit without a soldering iron

You already understand that successful soldering requires heating the part to the melting temperature of the solder. It can be melted using a heat gun or soldering hair dryer. This is an analogue of a construction hair dryer, only it is compact and often equipped with special molded nozzles.

With its help, the working area is heated, while the solder melts not at a certain point, but over a relatively large area. This is an effective method, especially if it is necessary to desolder the microcircuit (all legs heat up at the same time). But with this method there is a risk of damaging the part itself from overheating.

If you remove the faulty element, no problem.

In general, a soldering gun should only be used in cases where the traditional soldering method is not possible. For example, when mounting SMD parts (who doesn’t know, they don’t have legs) on a radiator plate.

Flux selection

We will talk about soldering copper parts. There are special acid compositions for iron and aluminum; this is a topic for a separate material.

In fact, it's everyone's personal preference. You just need to try different formulations and determine the best one for yourself. Some people like soldering fat (the consistency is like grease), some like liquid flux. We will talk about traditional rosin.

More precisely, how to solder correctly with it.

This flux is based on pine resins and has excellent cleaning properties. It provides mechanical and chemical cleaning, in addition, it protects the surface well from oxidation when heated. There is only one drawback: in its pure form, rosin is solid. This means that it cannot be applied to the parts to be joined in advance. However, the technology is there:

• Having touched the rosin with the tip of the soldering iron, we collect solder on it;
• we immerse the legs of the part or the wire in the flux using a soldering iron (it melts), while the surface is covered with a thin layer of solder;
• similarly apply solder to the soldering area;
• connect the tinned part (wire) to the soldering point;
• touch the flux with a soldering iron, then pick up solder, dip it in rosin again;
• Immediately transfer the tip to the soldering zone.

Parts have been soldered this way for many decades. With a certain skill, there are no restrictions on the choice of materials for joining. This technique is ideal for training. If you master it, the other methods will seem even easier.

Tip: To clean solder surfaces that have a layer of oxide on them, regular pharmacy aspirin is suitable. It contains acetyl salicylic acid. It must be ground into powder and applied to the contacts.

Soldering with liquid or paste fluxes

The advantage of such compounds is that they can be pre-applied to the connection point. That is, the flux begins to work even before heating. When touched with a soldering iron, the second stage of the reaction occurs, and the liquid flux serves as a lubricant for the spreading of solder.

Another plus is that a paste or liquid cleaner increases the contact patch. The main problem with soldering non-flat objects is that the heat transfer area from the soldering iron is minimal. If the point of contact is moistened with flux, the temperature is transmitted more efficiently.

The only drawback: there is no mechanical impact on the surface.

Information: some old-school professionals dissolve pine rosin with alcohol or a more liquid flux, and an effective composition is obtained with virtually no drawbacks.

What kind of solder to solder

These alloys are made from tin, lead, copper, nickel, or silver. Tin-lead solder (PLS) is used to work with circuit boards and household wiring. Despite the great variety, they can be divided into two types:

• soft (melting point up to 300°C);
• solid (melting point over 300°C).

Any form of release: lump, wire, powder, paste. A universal option is wire up to 2 mm in diameter. It is convenient to put it on the soldering iron tip or insert it directly into the soldering zone.

An interesting offer from manufacturers is solder paste or powder. This is finely dispersed solder, to which liquid flux is added for viscosity. The result is a consistent composition with high adhesion, which can be used for soldering without prior fluxing. We simply apply the paste to the contacts and heat it up.

You can work without a traditional soldering iron, using a soldering iron. Thanks to the fine grinding, the solder melts quickly and instantly spreads over the work area (with the help of flux).

This is a good option for a beginner master. The work is simple, but you won’t be able to learn how to solder efficiently in difficult conditions: when you don’t have good flux and solder at hand.

How to solder with copper

Copper, nickel or silver are used as the base for specialized solders that are not used in consumer electronics. Copper solders have a melting point of 800–900°C, so it is impossible to work with them in relatively delicate printed circuit boards. With their help, contact pads are soldered in electrical engineering; the main application is the assembly of copper pipes. The composition is produced in the form of wire.

Practical advice in unusual situations

• Installation and dismantling of elements with two legs is easy. How to desolder a microcircuit from a board with a soldering iron, since you need to heat several legs at the same time? Use a heat-conducting object with a large area. For example, copper braid.
• If, after removing parts from the board, the hole is closed with solder, use a toothpick.
• A third-hand clamp can be used to secure elements before soldering.

Bottom line

Despite the abundance of theoretical advice, only practice will help you learn how to solder correctly. Take a faulty circuit board from any electronics, remove and solder the components several times. The same applies to splicing wires. A couple of meters of used wiring is enough to get practical experience. Then start the real work.

Source: https://ProFazu.ru/elektrooborudovanie/samodelki-oborud/kak-pravilno-payat.html

Wave Soldering: Limitation of Use

Group wave soldering, used in the assembly of printed circuit boards, is a technology that has proven itself over many years. With the help of compressors, a continuous flow is created in a bath of molten solder - a wave of solder, through which a printed circuit board with components installed on it moves. When the bottom of the PCB comes into contact with the wave of solder, solder joints are formed.

The main purpose of this technology is effective automated soldering of various types of both SMD and TNT (lead) components. To minimize the risk of wave soldering defects—short circuits and missing solder joints—a number of factors should be taken into account at the board development stage.

Three principles on which this technology is based: the correct choice of the element base nomenclature, the competent layout (design) of the printed circuit assembly and the choice of the correct geometry of the contact pads for the components on the bottom side of the PCB.

Element base

Restrictions on the use of certain types of components on the bottom side of the PCB in the case of wave soldering are imposed by the very principle of this technology - the formation of solder joints by “washing” the components and (or) their leads with molten solder.

Type of component that should not be placed on the underside of the PCB Cause

Pin-type components (TNT)	Cannot be sealed (or may be destroyed) when dipped in molten solder
SMD components with case height greater than 3.5 mm	Low soldering efficiency due to the “shading” effect, high probability of snagging on solder bath structural elements
SMD components with small lead pitch (less than 0.8 mm)	High probability of short circuits between adjacent terminals
Components not suitable for wave soldering	Components that can be destroyed or partially lose their properties when immersed in molten solder, for example, SMD LEDs

Printed Assembly Layout

The very design of TNT components implies contact with solder during soldering only of the leads through the holes. The preferred arrangement of TNT components with several rows of pins - for example, DIP chips or connectors (especially with a number of rows of 3 or more) - is with the long side perpendicular to the wave front (parallel to the direction of movement of the board along the conveyor).

This is explained by the fact that when a number of closely spaced leads come out of the molten solder, there is a high probability of short circuits due to the retention of solder between the leads due to the action of surface tension. If the rows of leads are located along the direction of movement of the board, the leads are sequentially separated from the solder, ensuring sufficient drainage and minimizing the likelihood of a short circuit.

The basic principles of the location of SMD components relative to the solder wave front are the arrangement of microcircuits with parallel rows of leads - the long side along the direction of movement of the board (similar to TNT chips and connectors), square packages (such as QFP) - at an angle of 45 degrees, to ensure consistent separation of the leads from solder and eliminate the shadowing effect, components with two leads (for example, Chip resistors or diodes in an SOD package) - the long side parallel to the wave front, to eliminate the shadowing effect.

It is undesirable for SMD components to be located close to each other, especially if they have different heights - this leads to the shading of the contact pads by the housings of adjacent components and, therefore, prevents soldering. It is recommended to place passive components at a distance of 1-2 times the maximum chassis width of adjacent components. You should also avoid close proximity of the leads of SMD, TNT components and open vias - the likelihood of a short circuit is very high.

Geometry of pads

Wave soldering is a combination of the forces of attraction of molten solder to wetted surfaces (exposed conductors, pads, component leads) and repulsion of it from non-wetted surfaces, such as the solder mask or SMD component packages. If the pads are very small, or located in “hard-to-reach” areas of the PCB, this will make it difficult for the solder to reach them.

Due to the action of the forces of repulsion of the molten solder from the surface of the PCB and the component body, the meniscus of the solder, when it moves, does not reach the contact pad, the so-called effect of “shading” of the contact pad and the output of the SMD component with its own body occurs - soldering does not occur in this case . The only way to ensure solder access to the solder joint in this case is to increase the size of the pad away from the component.

In this case, the wetted surface of the CP is, as it were, removed from the shaded area and “pulls” the solder towards the terminal. The increased dimensions of the contact pads of SMD components are a fundamental factor in reliable and high-quality wave soldering.

When choosing the geometry of contact pads for SMD components, in case of wave soldering, it is recommended to be guided by the requirements of the IPC-7351 Generic Requirements for Surface Mount Design and Land Pattern Standard, using data for density level A (Most Land Protrusion).

More articles on PCB assembly and wave soldering:

Source: http://sepco.ru/montage/pajka-volnoj-ogranichenie-ispolzovaniya.html

How to solder: soldering procedure, choice of soldering device and choice of solder for soldering - SibNovStroy

Whatever innovations the modern market of tools for repairing radio equipment offers, the soldering iron remains one of the most reliable and safe devices.

How to solder correctly with a soldering iron: what is required for soldering using rosin

The process of soldering wires and microcircuits is considered effective because it allows you to achieve the strongest possible connection between wires and small parts.

This result can be achieved by adding a special material to the contact area - solder, which has a lower melting point than that of the parts being connected.

Thus, soldering with a soldering iron is the effect of a certain temperature on different metal surfaces for their strong and high-quality connection. However, before you start working with a soldering iron, you should first understand the rules of soldering and other intricacies of this process.

What you need for soldering with a soldering iron

To solder something, you first need to prepare all the tools necessary for this process.

• Of course, you will need a soldering iron itself. For working at home, the best option would be a soldering iron with a power of 15 to 30 watts. The choice of device power directly depends on what exactly you plan to solder. For simple parts, a soldering iron with a minimum or medium power is suitable, while for more professional soldering, a 40-watt device will be most practical.
• You will definitely need solder, which is very important to choose correctly. The main function of solder is to create a permanent connection during the soldering process. Currently, there are several types of solder that are designed to solve different problems (copper, silver, tin, lead, etc.). However, rosin is quite suitable for sealing contacts in a microcircuit or for ordinary connection of wires. It is not recommended to use it in electrical engineering, since the acids contained in rosin can simply destroy contacts and destroy complex parts of the circuit. It should be remembered that only correctly selected solder can provide the best connection of parts.
• When working with a soldering iron, to clean and tin the “tip” of the device, you will need to use flux - a special mixture of organic or inorganic origin necessary to remove acid particles released by solder from the tip of the tool. Flux comes in powder, liquid or paste form. Despite the huge selection of different fluxes, the flux made from rosin is considered the most versatile and most effective.
• In order to use a soldering iron with maximum convenience and comfort, you should prepare a special stand for it. Since the device has a very high heating temperature, in order not to burn things or objects, it is necessary to prepare a stand that can withstand high temperatures.
• You will need a file. To make the soldering process simple, you need to sharpen and clean the soldering iron tip with a file. The main thing is that the “tip” of the tool is smooth and has no signs of carbon deposits.
• Also, to work with the device you will need a vice or pliers - with their help you can clearly fix wires or boards and guide them to the desired position during the soldering process. If these tools are not at hand, as a last resort you can use tweezers.
• After finishing working with the tool, you will need to use alcohol, which can be used to wash off traces of flux.

Having all the necessary tools at hand, you can start working with a soldering iron .

How to solder correctly with a soldering iron and rosin

Rosin has such unique qualities as ease of dissolution in various organic compounds, for example, acetone or alcohol.

When heated, this substance can break down complex chemical compounds such as copper, tin or lead.

Therefore, proper use of rosin helps reduce the likelihood of spreading of the substance, destruction of the oxide coating, as well as high-quality tinning of soldered elements.

You also need to take into account that the thinner the tip of the soldering iron, the easier it will be to work with it, especially when it comes to soldering very thin wires and parts. Therefore, if it has not yet been sharpened, this should be done before starting work.

Process description

• First, you should prepare the workspace where you plan to seal the parts. To do this, you need to open the window, since the fumes that come from the solder heavily pollute the air. You should also take any sponge, soak it thoroughly in water and place it as close to the soldering iron as possible. Well, in order not to stain your work area with drops of solder, it is best to cover the surface on which you will be working with thick cardboard or some other similar covering.
• There must be a stand for the device at hand.
• Then you need to plug the soldering iron into a power outlet and heat it up. As the device heats up, a specific smell and noticeable smoke may appear - this is normal. The device will be ready for use immediately after the tip is completely heated and the smoke and unpleasant aroma have evaporated.
• After the tool has been calcined, it should be turned off. This is necessary in order to pre-clean the tip from dirt and plaque. It is best to clean the instrument while it is hot. To do this, you can use a prepared sponge or cloth.
• Then you need to turn on the soldering iron again and let it warm up thoroughly.
• After cleaning and heating the tool, you should carry out the process of tinning the tip of the soldering iron - covering the tip with a light layer of solder, in this case rosin. Thanks to this simple manipulation, the heat transfer between the parts that are intended for soldering will significantly increase.
• Next, you need to dip the tip of the heated device into rosin for a while so that a little solder accumulates on the tip. You should wait a little while until the solder heats up and begins to soften.
• Excess rosin can be removed using cardboard or other available tools.
• If you plan to solder one copper part, then one tinning will be enough - you need to touch the rosin once, then apply the tip of the soldering iron with solder to the working surface and wait a little until the wires are covered with solder. As a result of these manipulations, the rosin will begin to smoke, and the soldered parts will flow around the molten substance.
• In order to solder two parts efficiently, they also need to be tinned separately, that is, covered with solder. It should be remembered that the tinning process is a mandatory procedure, without which it will not be possible to properly solder the necessary parts.
• After finishing work with the soldering iron, while it is still warm, you need to remove the remaining solder. To do this, the tip of the tool just needs to be wiped with a damp cloth, or better yet, a sponge soaked in alcohol or any other composition intended for these purposes.

There should not be any particular difficulties when working with the tool. For everything to go smoothly, it is best to first practice working with rosin on parts that you won’t mind throwing away later. After all, experience always comes with practice.

Soldering wires

In order to correctly solder copper wires using rosin, you must follow a certain sequence of actions.

• First prepare the wires . To do this, the ends of the wires that need to be soldered must be thoroughly stripped of insulation. All wires spliced ​​together are usually insulated using a special heat-shrinkable tube. If such a tube is present, then it must be cut using a sharp knife so that the length extends 2-7 mm beyond all seams. The insulating coating should be about two centimeters on each side of the wires being connected. The exposed ends of the wires must be burned to completely remove the insulation.
• Then the connected ends of the wires need to be provided with a high-quality mechanical connection. To do this, the two ends of the wire are twisted together so that their centers intersect tightly with each other. After this, the end of one wire should be twisted along the length of the cable. The same manipulation should be done with the second end of the other wire.
• Then you need to heat up the soldering iron to first tin the wires and then warm them up. To do this, a heated soldering iron is lowered into rosin and a little solder is taken, after which the device is passed a couple of times along the ends of the wire. During tinning, the wire should be rotated and heated, which will help ensure an even coating of rosin.
• At the end of the work, the finished wire should be insulated . To do this, you need to put the heat shrink back on the already soldered wires. This will not only help cover the connection, but also heat it, making the soldered wire strong and flexible.

As you can see, there are no particular difficulties with soldering wires using rosin. The main thing is not to forget to tin the wire and check the quality of the soldering. If necessary, tinning should be repeated several times until the wires are firmly connected with solder.

Important Tips

Having figured out how to use a soldering iron, you should consider several recommendations for working with this tool.

• Before starting work, to ensure high-quality soldering of parts, you should always clean the tip of the tool. You need to understand that only thanks to the soldering iron tip the thermal conductivity and quality of the connection are enhanced. You can use a damp sponge for cleaning. After cleaning, the tip of the device should be immediately dipped in rosin so that it is covered with a thin layer of solder, which prevents oxide deposits from interfering with high-quality soldering of parts.
• You should always solder small and thin parts first, since the tip of the device at the beginning of its use will be as thin and precise as possible.
• Before soldering parts, their surface must be thoroughly cleaned of dirt and acid. Cleaning the surface of soldered objects is done using a sharp tool - sandpaper or a regular knife. This is done until the surface of the wires noticeably brightens. After which the contacts are tinned and connected using solder.
• If you need to solder some part without using a soldering iron, you can use rosin, previously dissolved in alcohol. The resulting mixture can be applied to the desired surface using any thin tool, such as a screwdriver.
• The highest quality soldering can be achieved by using solder with rosin.
• In order to correctly and tightly solder wires and other parts using solder, you first need to heat the joints with a soldering iron.
• The mistake of many is poor heating of the soldering iron. If this happens, the parts do not connect well. Therefore, before you start using the tool, you need to warm it up thoroughly.
• However, severe overheating of a soldering iron with maximum power can also negatively affect the quality of work. You need to understand that there are different temperature conditions intended for a specific type of work.
• Soldering temperature is a very important nuance. For example, to seal various microcircuits, the temperature should be no more than 250 degrees. But in order to connect radio components, you will need to heat the soldering iron to more than 300 degrees.
• When working with electrical appliances, safety precautions must be observed. To do this, you need to make sure that the window is open and the socket is working. This is due to the fact that when working with solder, harmful chemical elements are released that negatively affect health. As for the serviceability of the outlet, this is also a very important point - in the process of severe overheating, fires often occur. Therefore, the workplace must first be prepared and secured, and only then can we begin to work.

If you take note of these little tricks , the process of soldering parts will go quickly, and most importantly, with high quality.

Summing up

A soldering iron is a universal tool with which you can quickly connect broken wires or contacts, as well as quickly repair a microcircuit or connect light metal surfaces.

The ease of operation of the device allows any man to learn how to use it in the shortest possible time.

And what is important: working with a soldering iron does not require any professional skills.

Source: https://sibnovostroy.ru/obrabotka/kak-payat-protsedura-payaniya-vybor-payalnogo-ustrojstva-i-vybor-pripoya-dlya-pajki.html

Which solder to choose for soldering: types, brands and characteristics

In the manufacture and repair of electrical equipment, skills in handling a soldering iron are constantly required, and solder and rosin are used for soldering; in the middle of the last century, tin was used for these purposes, but not in its pure form, since this is a very expensive pleasure, and alloys with other fusible materials metals.

Which ones are there?

What is solder and how to choose it correctly - in practice they can be soft or hard . Installation of any radio-electronic equipment occurs using low-fusible options.

Components of unknown origin differ in the following characteristics:

1. The rich shine of the cut indicates a high presence of tin.
2. The predominance of lead guarantees the substance a dull gray color and a matte surface.
3. With an increased lead content, the product becomes plastic; for example, a wire with a cross-section of 6 mm is bent by hand without visible effort.

Sometimes, for high-quality soldering, a ready-made mixture is used - this is solder in the form of a wire, and the flux is sealed inside. Manufacturers produce similar substances with flux tolerance within 1-3% of the total weight, which has a beneficial effect on the soldering process and increases labor productivity, since there is no need to constantly dip the soldering iron tip into a jar of flux.

Based on consistency, they are available in two types: soft or hard solder, and based on the melting point, ordinary and refractory types are distinguished.

Solder wettability

This term means the adhesion of molecules of a liquid melt to a solid surface, the degree of which determines the fluidity of soldering . For good soldering, liquid solder qualitatively wets the surface where soldering occurs, and its boundary forms an acute angle.

Dried flux can only be removed by mechanical cleaning, because additional alloy has appeared. If a drop of molten substance forms an obtuse angle with the surface, then this indicates unsatisfactory wetting quality, which is counteracted by dirt, grease stains or a metal oxide film.

Options for wettability of soldering surfaces with molten flux.

Melting temperature

The main criterion for choosing high-quality alloys is that they must come into a liquid state earlier than the structures being joined , and the melting point of the solder differs significantly from that of another type, for example, those containing lead impurities.

The presence of different impurities affects the ability to melt at the same temperature, for example, POS-40 melts when it reaches 238 0C, but there are refractory solders and special devices are used for their melting.

Low temperature options

In first place is the VUDA alloy with the composition: 10% Sn and Cd each, 40% Pb and Bi, the beginning of the melt is 65-72 0C. The second position is occupied by a solder called ROSE, which begins to melt at 90-94 0C. Consists of: 25% tin and lead each, and the remaining 50% is bismuth. The above alloys are expensive solders.

The third place among low-temperature products is occupied by POSK-50-18, with a temperature of 142-145 0C. This solder contains 50% tin, 32% lead and 18% cadmium, which enhances corrosion resistance but adds toxicity.

The second nominee (called ROSE) is very popular among radio amateurs, but in domestic radio electronics its marking is POSV-50, where the numbers are the percentage of bismuth. Used for installation/dismantling and tinning of overheat-sensitive copper tracks on printed circuit boards.

Soft look stamps

Solder for soldering in this category is used with a ready-made flux located inside the wire, so melting occurs simultaneously . A product called Tretnik has become widespread because it contains a third of the lead of the total composition. Tin, which is part of the alloy for soldering, is environmentally friendly, so it is allowed to use this type in the food industry.

Soft types of solders are used for soldering parts that are afraid of overheating, for example: transistors or fuses. Due to its toxicity, WOOD alloy is used in limited areas of human activity.

Domestic alloys are marked with the abbreviation POS, but if there are other substances, a letter corresponding to the name is added at the end, for example, POSV-33 - this solder contains equal parts of tin, lead and bismuth.

Main technical parameters

Soldering materials are divided according to the following parameters:

1. Conductivity , for example, solders containing aluminum have better similar values ​​than those marked PIC.
2. Tensile strength , unit kg/mm. This parameter directly depends on the percentage of tin.
3. Melting point , which depends on the chemical composition.

Table of temperature and application depending on the chemical composition of the solder.

Flux

Solder with rosin in the form of a hollow wire twisted into rings is common on sale . A flux of similar composition is made from coniferous trees; such a substance becomes soft when heated to 50 ° C, and at 250 ° C it begins to boil with partial evaporation. Rosin must be removed after finishing work, otherwise oxidation will occur, and the substance, absorbing moisture from the air, will begin to interfere with the proper operation of the devices.

Popular formulations

There are three main categories:

1. Light-colored rosin is used when joining copper and other soft non-ferrous metals; an alcohol solution with a concentration of one to five is used in a hard-to-reach area of ​​adhesion; and a mixture of glycerin and rosin is used for hermetic soldering.
2. Fluxes containing alcohol, petroleum jelly or zinc chloride are used to permanently bond non-ferrous and precious metals. The use of paste is justified by the fact that it is more convenient to apply it in the required quantity to the product.
3. Acid-active substances are produced in liquid form, for example, orthophosphoric acid, which has a density of 1.7.

Pasty

Tinol paste has become widespread and is used for soldering various products in hard-to-reach places. It is applied with a spatula, followed by active heating with a soldering iron or other, more powerful electric tool. Often used by inexperienced performers who do not have the skills to work with tin and rosin.

Using PIC

The discoverers of this alloy were pleasantly surprised that it turns into a molten state at a lower temperature, and the eutectic mixture can act as a solvent for the added metal. This is how the very first brands of POS solders were developed.

Lead options

Such mixtures containing lead are characterized by softness, rapid melting and easy processing, which is why they are called lead-containing solders. They are harmful and have been banned for use in soldering electrical components around the world . The percentage of cadmium, mercury, and similar harmful components in equipment is strictly regulated and verified by relevant organizations.

Lead free

Lead-free solder must not contain harmful metals and is considered environmentally friendly, not causing harm to the environment and the solder performers. The simplest example is tin solder, which contains pure tin, has increased wettability and high electrical conductivity. To combat deficiencies, copper, silver and gold are added to them, which helps make the substance harder.

Such a product has an increased melting temperature, but it has not yet been possible to find a complete alternative to standard types of solder, but the main indicator is harmlessness. Tin occupies a major place in the chemical composition, so its inherent properties have a great influence on the solder, because of this, the melting point of lead-free solder is lower, and the material is softer.

Colophon resin

This is the name of the well-known rosin - an amorphous substance with a characteristic fracture and glassy sheen when chipped . In addition to the fact that it has a natural dielectric property, the following features are known:

• dissolves well in gasoline, alcohol, ether and acetone, but remains indifferent to the effects of water;
• the melting point varies between 50-70 degrees, but sometimes rises to 130 0C;
• the chemical composition contains up to 90% resin acids, the basis is abietic acid;
• easily destroyed with minor mechanical impact.

The color varies from light yellow to dark brown shades, which depends on the degree of purification and indicates the amount of foreign impurities. Excellent electrical insulating properties belong to lemon-colored resin.

Secrets of choice

The task of any performer is to create a strong and reliable fastening of radio components to the board, therefore the selection of solder is carried out according to the following parameters:

1. The composition of materials to be soldered - here it is necessary to take into account the characteristics of the material, its ability to overheat and much more.
2. When soldering wires or other large objects, refractory solders are used.
3. Sometimes it is necessary to use solder that has a high ability to conduct electric current; it must be taken into account that the resistance of tin is much lower than that of lead, therefore expensive brands of solder are used for soldering high-frequency circuit boards.

In each specific situation, the performer must clearly know the correspondence of the solder and the product being connected in order to choose the best option for high-quality soldering.

conclusions

Today there is an abundance of different solders on sale, as they say, for all occasions, but you should choose proven samples that will help solder the product with high quality and with high reliability during operation.

Source: https://svarka.guru/payka/oborudovaniya/pripoy.html

Solder for soldering wires which one to choose

Greetings to dear readers! In this material I tried to collect all the data about PIC solder. This Tin-Lead Solder is the most popular solder for mounting radio components and is used more often than others in radio engineering. I will try to explain why this is so and tell you about the types and technical characteristics of POS series solders. I’ll also tell you a terrible secret about POS-60 and POS-62 solders. Go!

Types of POS solders

First, let's remember what types of solders are made from alloys of the tin-lead group. The most popular are antimony-free solders POS-10, POS-40, POS-61 and POS-90. POS solder containing antimony is called POSSU. Antimony in the solder adds several percent to its strength.

When we talk about melting a mixture of tin and lead, we need to remember the definitions of solidus and liquidus . When any mixture of two or more metals is heated, the melting (transformation from solid to liquid phase) of the lightest particles occurs first. This temperature mark is called the solidus of the alloy.

With a further increase in temperature, more refractory components begin to melt. As soon as they melt, the liquidus . The PIC solder is now completely melted. This process is explained in more detail by a picture taken from a presentation on the topic of alloys.

Between these two points is a state of increased ductility of the solder . In this state, the solder can be pulled and deformed without losing integrity.

There are eutectic alloys - solders, in which the solidus and liquidus points coincide. This is very convenient when soldering and indicates the high quality of the solder.

About the composition of solder

The name of the solder of the tin-lead group indicates the tin content in it. For example, POS-40 contains 40% tin, and POS-61 contains almost 61% tin. The rest consists of lead and additional impurities.

By appearance, you can estimate the composition of the solder by eye. If the PIC solder is more matte and dark, then it contains more lead. If it is lighter and shiny, then there is more tin. This is best understood by comparison.

Look at the photo to see what a sheet of tin and a sheet of lead look like.

The strength of solder depends not only on the alloy alloy, but also on the metal being soldered. For example, to solder copper or zinc, several percent of copper or zinc are added to the POS solder, respectively. This reduces chemical erosion of the metal and increases the surface strength of the joint.

Solder alloying

To improve performance characteristics, alloying of solder with the following substances is used:

• adhesion is improved by the addition of copper, cadmium, antimony, aluminum, silver and zinc;
• ductility and resistance to thermal cycling are improved by the addition of indium, silver, manganese, bismuth, and lithium;
• Nickel, cobalt, zinc, silicon, boron, iron add strength
• The corrosion resistance of solder is increased by nickel and copper;
• Heat resistance is increased by silicon, zirconium, tungsten, vanadium, cobalt, niobium, hafnium.

Technical characteristics of POS and POSSu solders

In order not to describe all the technical characteristics of solders of the tin-lead group, I will simply provide a table of parameters. It can be used to determine the melting point, density, electrical resistivity, thermal conductivity, tensile strength, elongation, impact strength and Brinell hardness of solders.

Analysis of the table shows that the most fusible among the list is cadmium solder POSK 50-18 with a melting point characteristic of 145 degrees Celsius. The strongest solder is POSSu 4-6 solder with a tensile strength of 6.5 kgf/sq.m. mm.

Technical characteristics of POS-10 solder

POS 10 solder has a distinctive chemical composition. It contains 9-10% tin, about 89% lead, 0.2% bismuth, 0.1% antimony and other impurities in small quantities. POS-10 solder is used for soldering and tinning contact surfaces of electronics. For example, they solder relays and fill control plugs in radio electronics housings.

The POS-10 soldering temperature is 299 degrees Celsius. The solidus point is 268 degrees.

• high melting point is useful when soldering equipment cases.

• low strength and tensile strength of about 3.2 kgf/sq.mm.;
• high resistivity - 0.2 Ohm x sq.mm./m;
• high content of lead, which is hazardous to health.

Technical characteristics of POS-30 solder

Solder for soldering of the POS 30 brand is an intermediate link between POS 10 and POS 40. The composition of POS 30 solder is as follows: 30% tin and 69.5% lead. The rest is impurities and doping.

Solder POS 30 can be easily replaced with POS 40, which is described below. The melting point (liquidus) is 238 degrees, and the plasticity temperature (solidus) is 183 degrees Celsius.

According to the technical characteristics, POS 30 solder is most often used for soldering and tinning of zinc sheets and radiators.

• good adhesion;
• high strength.

• high lead content;
• often produced in rods.

Technical characteristics of POS-40 solder

According to the chemical composition, POS 40 solder consists of 39-41% tin, 59% lead. The remaining impurities are in the same ratio as in POS-10. Soldering solder POS-40 is often used for soldering and tinning radio equipment casings made of galvanized iron with galvanized seams.

The soldering temperature of POS-40 solder is 238 degrees Celsius, and the solidus is 183 degrees.

• good ratio of ductility and melting point;
• because of this, it tolerates thermal cycling better than POS-61.

• high lead content, which is harmful to health;
• elevated liquidus temperature.

The terrible secret of POS-60 solder

Now the time has come for the terrible secret of POS 60 solder . According to GOST 21930-76 entitled “Tin-lead solders in ingots. Technical specifications" and GOST 21930-76 "Tin-lead solders in products. Technical specifications", solder such as POS-60 simply does not exist. download and view GOST 21930-76 itself . Here is the complete table from this GOST.

So “ POS-60 ” is jargon or a popular designation for “the solder that everyone solders with.” It seems to me that this is due to confusion in the designation of POS-61. Because when the tin content in the solder according to GOST is from 59 to 61%, it is more logical to call it POS-60 rather than POS-61.

Among the solders produced according to international standards there is Sn60Pb40 solder . This is a solder solder containing 60% tin and 40% lead. It could be called POS-60, if at least specifications for it were developed. According to international data describing the characteristics, the melting point of 60/40 solder is 191 degrees Celsius.

The same story with POS-62 type solder . Such lead solder according to GOST has not yet been invented. So, if they ask me “what is the melting temperature of POS-62 solder,” I know that the answer with the figure 184 degrees Celsius must be looked for in the imported solder catalog. For example, you can use the Kester solder catalog.

Technical characteristics of POS-61 solder

The designation of POS-61 brand solder, as we found out, is quite controversial, but you can’t argue against GOST. POS-61 is used for soldering and tinning of electronic components and printed circuit boards of precision instruments with highly hermetic seams, for which overheating is not allowed.

Composition of POS-61 solder

The chemical composition of POS-61 solder is as follows:

• Tin 59 - 61%;
• Antimony - no more than 0.1%;
• Copper - no more than 0.05%;
• Bismuth - no more than 0.02%;
• Arsenic - no more than 0.02%;
• Iron - no more than 0.02%;
• Nickel - no more than 0.02%;
• Sulfur - no more than 0.02%;
• Zinc - no more than 0.002%;
• Aluminum - no more than 0.002%;
• Lead - everything else - about 38.7 - 40.7%.

Source: https://MyTooling.ru/instrumenty/pripoj-dlja-pajki-provodov-kakoj-vybrat

Solder with rosin

When performing metal soldering, there is always a need to use solder, the quality of which directly affects the durability of the completed connection of metal parts. It should be said that solder is a consumable material and is made from various alloys.

Manufacturers are constantly improving this material, which ensures high-quality connections and simplifies soldering. Rosin solder is an inexpensive and at the same time high-quality material that is versatile and can be used for soldering various metals.

This solder contains rosin, which eliminates the need to purchase and use additional materials. Rosin simplifies the melting of the surfacing material, which in turn improves the quality of the joint. Another constant advantage of such solder is its low melting point, and this in turn allows you to avoid changing the structure of the base metal being connected.

The flux in the solder is in the form of rosin, so there is no need to use it additionally. This greatly simplifies the soldering procedure, which professionals and ordinary homeowners will appreciate. Note that the percentage of rosin is in the optimal amount, while using it separately, there is a danger of taking more and less material. All this has a positive effect on the quality of welding work performed.

Types of rosin solder

Currently, such solder with rosin is manufactured in several versions. It is customary to distinguish such filler material depending on the rosin content, wire thickness and a number of other features. There is a choice of materials for both home use and soldering on an industrial scale. This solder is produced in the form:

• In reels. This is a universal option for surfacing material that can be used by both professional welders in workshops and ordinary homeowners for soldering at home. The thickness of the wire can vary from 0.8 to 2 millimeters. Note that using such coils is extremely convenient. You just need to select the appropriate brand of solder and wire thickness.
• In a tube. This type of solder is made exclusively for home use. Such a tube contains a minimum of material, so if large volumes are needed, you should either buy a large number of tubes at once or choose solder in a coil.
• In the bays. A large amount of material is used, so this design is intended primarily for industrial use. The thickness of the wire can be varied, depending on the specific needs of customers. The coils themselves can be made in different sizes, which somewhat simplifies their use.

Physico-chemical properties of the solder used

The classic composition of such solder with rosin is considered to be tin-lead soft alloys. tin is 60% and lead 40%. Accordingly, such a composition gives such solder certain physical properties.

The presence of rosin allows for excellent flexibility, as a result of which, before welding, you can select the right amount of such material and correctly position it in the seam. It must be taken into account that such a composition has a low melting point, so it is not possible to use it for joining refractory metals.

At the same time, we note that such solder penetrates in a liquid state into all cavities and irregularities, which ensures the strength of the connection. But at the same time, such an additive does not penetrate into the base material.

Low melting temperatures ensure ease of soldering. Lead adds fluidity to the material, but one should take into account the fact that lead may contain toxic fumes, so it is best to perform soldering in a ventilated area. No further precautions are required when soldering.

How to choose the right solder

When choosing one or another type of such material, you should take into account the convenience of doing the work. In the event that standard work is performed, then you can use solder with any optimal brand of rosin. If you work with so-called PIC materials, it is best to choose solder, the components of which are silver. This will allow you to ensure high strength, softness and subsequent strength of the connection.

In each specific case, depending on the metal alloys used in the solder, its melting point can vary significantly. The choice in this case must be made solely depending on the characteristics of the main metal parts you are connecting. All this will ensure the durability of the soldering and the quality of such a connecting seam.

Also pay attention to the melting point of the solder and metal. The higher the temperature of the base metal, the higher the same indicator should be for the solder. In addition to the brand of such material, you also need to decide on the thickness of the wire.

In this case, the choice must be made based on the thickness of the products themselves and the existing thickness of the weld. If you work with a soldering iron, then you can fuse a drop of flux of the required size from wire of any thickness. If you use gas welding, then you should use wire with a thickness of 0.8 to 1.5 millimeters.

However, we note that the composition of the material is a much more important characteristic than its thickness.

Features of use

Having correctly identified and selected the solder and rosin used, you can perform the soldering itself. This work is not particularly difficult. It is necessary to perform appropriate surface preparation, for which the base metal is cleaned of existing contaminants and all settling parts.

When preparing a surface for soldering, it must be heated and the solder melted. Remember that there should not be a large difference in temperature between the metal alloys and the solder, as this will subsequently negatively affect the quality of the connection.

There is no need to overheat the base metal; subsequently, the solder can spread over such a hot surface, cooling for a long time and not hardening for 10 minutes or more. The presence of rosin greatly simplifies soldering, and the solder quickly hardens, providing mechanical strength to the connection.

This ensures the necessary protection of the connection against corrosion.

Currently, solder with rosin from various manufacturers can be found on sale. These can be both domestic companies and foreign manufacturers. It should be said that there is no significant difference between domestic and foreign manufacturers.

Therefore, first of all, focus on the composition of the material, its brand and the thickness of the wire. By purchasing solder from domestic manufacturers, you can save a lot.

At the same time, you can be completely confident in the quality and durability of the soldered connections of metal elements.

Source: https://svarkagid.com/pripoj-s-kanifolju/