What is solder paste for?

Advantages of using solder paste

Solder paste is a substance that consists of flux, mechanical solder, various activators and binding components. The soldering process itself is a complex and painstaking work that requires full concentration from the master. However, we should not forget that the final quality is influenced not only by human experience, but also by equipment.

Main advantages

In order to ensure perfect contact between the SMD parts and the microcircuit, it is necessary to correctly solder the element. Solder paste provides this bond and also helps break down the oxide film. But, despite all the obvious advantages, if this substance is of poor quality, then it can also have a negative effect on the circuit (when it dries, it leaves marks and forms bridges). In this case, we will get an uncontrolled connection of two adjacent elements, which can lead to breakdown.

Therefore, to make the soldering process as simple and efficient as possible, we need to find the perfect solder paste. Let's highlight the main characteristics that you, as a buyer, should pay attention to:

• viscosity;
• stickiness;
• composition of solder components (paste with tin and with the addition of lead is most often used, but lead-free is also available);
• particle size and shape;
• degree of oxidation, etc.

Where can I buy quality solder paste?

The TOPTREIDCO company sells products from the line of solder pastes of the French brand MBO (Metaux Blancs Ouvres). This is a truly unique offer: you can buy export goods of the highest quality at low prices. In the catalog you will find the following types of solder pastes:

• lead;
• lead-free;
• high temperature;
• low temperature;
• for dosing, etc.

If you represent the interests of a legal entity, you can request a commercial offer and select the products that are most interesting to you. Payment for the order is possible by payment to a bank account. All documents necessary for accounting reporting will be attached.

TOPTREIDCO always strives to be a customer-oriented company, so its main advantage is the speed of order processing and delivery. If you find packaging defects or properties different from those declared, you can return the product, since the warranty covers a full 12 months!

To buy solder paste, you need to send a request indicating your name, phone number and email address, after which a manager will contact you and help you place your order. Additional information on the company's official website.

Source: https://oborudka.ru/favorit160/27.htm

Solder paste for soldering without a soldering iron

Soldering technology is often used to join various alloys and metals. It involves the use of special equipment that is capable of providing a targeted thermal effect. In the absence of a soldering iron, soldering can also be carried out, for which special tools are used, for example, a soldering iron. Let us consider the features of such a process in more detail.

How to solder without a soldering iron

Using a homemade sting

To save money, many craftsmen decide to create a homemade tip. The operating principle of the soldering iron is quite simple:

1. There is a heating element that receives power from the power supply.
2. Heat is transferred to the sting, which has a pointed shape.
3. When the tip comes into contact with the material being processed, it heats up and becomes plastic.

You can make a homemade design as follows:

1. A piece of copper wire is required, which has a diameter of about 0.5 cm. A conductor can be used as a tip, one end of which is sharpened at an angle of 45 degrees. A small piece of fabric that is temperature resistant is also required.
2. One end of the cable is insulated. It will be used as a handle. Fiberglass is often used as an insulating material. Fixation is carried out using heat-resistant glue.

Homemade sting

Soldering without a soldering iron can be carried out using a fire source, for example, a gas stove. Using fire, the tip is heated, after which you need to touch the solder or rosin. Due to the use of a special material, the tip will become tinned and the tip can be used as a soldering iron.

Solder the garland using improvised means

Problems often arise with garlands that are used to decorate a home or tree. Due to the use of thin wires, they are often interrupted and soldering is required. Among the features of this work, we note the following points:

1. In most cases, the problem occurs in the control unit, since the wires are not attached securely.
2. A breakthrough may occur along the entire length of the product.
3. If all light sources are connected in parallel, then the failure of only one leads to an open circuit of the entire circuit.

It’s quite easy to find loose contacts, but a break is only possible when using a tester. Only after finding the break point can you start soldering. You can solder without a soldering iron as follows:

1. The broken wires should be cleaned.
2. You can make a small twist on which the paste is applied. It will be used to distribute the alloy used.
3. The next step is to melt the solder, which can be done using a lighter or a candle.
4. After this, the junction is isolated using a tube, which is also slightly heated to increase its ductility.

Similar technology can be used to restore the condition of headphones. The soldering procedure does not take much time.

Wires are prone to breakage. You can solder a wire without a soldering iron if you take into account several recommendations:

1. To begin with, the break point is located and the ends are cleaned.
2. After this, the wires are twisted together to create a strong connection.
3. The area being treated should be slightly warmed up. To do this, you can use a lighter or other heat source.
4. The solder is also heated to a plastic state, after which it is applied to the joint.

When working with large-section wires, you should grind the solder and sprinkle it on the surface, then heat the surface with a candle or lighter. In this case, the solder fills the free space, thereby ensuring reliable contact. When considering how to solder without a soldering iron, you should take into account the fact that only wires with a diameter of 2 mm can be processed in this way.

Soldering wires without a soldering iron

If you need to solder a flat element, then the parts are pre-tinned. At the time of soldering, the core is pressed and sprinkled with shavings of the selected alloy, after which the surface is heated.

Materials for soldering wires without a soldering iron

In general, we can say that the soldering procedure without the use of a special device is in many ways no different from the usual one. For this you may need the following materials:

1. Solder directly.
2. A restrictive element that will prevent the metal from spreading.

In addition, you need to pay attention to the process of cleaning the surface being treated. It is recommended to clean it of dirt and then degrease it.

Features of soldering in the groove

If you need to process wires with a diameter of up to 3 mm, you can do without a soldering iron; grooves are used for this. They can be made from aluminum foil, the thickness of which is 0.8 mm. Recommendations for soldering at home in this case are as follows:

1. Insulating materials are removed.
2. The damaged ends should be twisted together and then laid parallel.
3. A groove is made from foil that will cover the joint. It is used for solder distribution. It is recommended to use shavings.
4. The foil trough is heated with a candle or lighter. In this case, you need to be careful, as molten metal may leak out and cause burns. When working, it is recommended to use pliers.

If necessary, solder that has leaked out can be protected with sandpaper. The use of foil significantly increases the degree of insulation.

Soldering utensils or containers

Often there is a need to carry packs of dishes and other containers. Without a suitable soldering iron, work can only be done if the hole has a diameter of 6 mm. Among the features of the procedure, we note the following points:

1. POS60 is used as solder. This alloy is characterized by more attractive performance characteristics; the created patch can withstand significant mechanical stress.
2. The area around the defect is cleaned. It is recommended to create a surface that resembles a funnel.
3. Treatment is carried out using hydrochloric acid. It is able to remove all contaminants from the surface being treated.
4. It is recommended to place a plate on the reverse side that will prevent solder from leaking out. After the alloy hardens, the plate is removed.

Solder POS-60 1mm

As before, the solder should be made with shavings that fill the hole. After this, the problem area is heated using a lamp or other heat source.

Solder paste for soldering without a soldering iron; application features

There is a special paste on sale that can be used as solder. In addition, you can make it yourself. Among the features of the work carried out, we note the following points:

1. The area being treated is cleaned. The insulation is removed from each wire. After this, it is necessary to degrease, since soot may remain on the surface of the veins.
2. Using a brush or other similar tool, apply the paste. It is worth considering that it must be distributed evenly over the entire surface of the connection. The brush is selected depending on the cross-section of the wire.
3. The area where the paste was applied heats up. To heat up the solder, a hair dryer or a homemade sting or a regular lighter can be used as a heater. It is necessary to ensure that the substance does not boil, as this can lead to a change in its basic properties.

Soldering paste without a soldering iron

The composition of the paste you create yourself may vary somewhat depending on the area of ​​application. After exposure to high temperature, the paste becomes a solid material that is resistant to mechanical and other stress.

Foil as a soldering method

The soldering method using foil is characterized by practicality. Typically, it only takes 5 minutes to restore the connection. Foil can be used as solder, which is unwound over the entire area and heated to a high temperature. Due to this, the plasticity of the material increases significantly; after cooling, it hardens.

Foil can be used in a variety of cases. An example is damage to the board or wire connection. Among the features of the work carried out, we note the following points:

1. Standard contact preparation is carried out.
2. The ends are twisted to form a joint. Due to this, the reliability of the connection is significantly increased.
3. The required amount of foil is cut off, the junction is wrapped in several skeins.

After this, uniform heating is carried out using a hair dryer or other heat source. When exposed to heat, the surface of the foil quickly becomes soft and plastic; after heating stops, it quickly cools and hardens, providing the required degree of sealing and strength.

  Safety precautions when soldering and tinning

In conclusion, we note that without a soldering iron it is almost impossible to carry out jewelry work, as well as soldering circuit boards. This is due to the lack of possibility of directed heat exposure. However, in some cases a soldering iron and other tools are not required.

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Source: https://respect-kovka.com/payalnaya-pasta-dlya-payki-bez-payalnika/

Why do you need solder paste - Let's make things together

The basic physical and chemical properties of solder pastes are determined by introducing 4 - 15% binders into the solder powder. It is they (sometimes with the addition of a solvent) that give the paste the desired consistency, prevent it from separating and spreading, and impart adhesive properties and adhesion to the substrate.

The binder is neutral to the solder during storage and soldering, and when heated, it volatilizes or melts without the formation of hard-to-remove solid residues. Organic resins or mixtures thereof, thinners and other substances are used as binders. Plasticizers and thixotropic substances are added to them.

The latter prevent the settling of solder powder particles during storage and ensure a specified viscosity range.

Solder paste application

Standard application of solder pastes is done using screen printing. An alternative to this process is to apply drops of paste point by point with a dispenser, but this is less productive.

Screen printing machines differ little in operating principle from similar machines for printing work, but the screen forms themselves are necessarily made of metal sheets.

Such machines are equipped with a stencil cleaning system that prevents solder paste from contaminating the board surface.

Solder paste is used as an alternative to solder. As a completely different structure, it has a number of advantages and disadvantages that limit its use or make it the only one possible. Solder paste contains several components:

• flux base;
• solder, i.e. metal fraction;
• binders are the basis that determines the consistency;
• for inactive fluxes (indelible) - activators.

Since such products are produced in different compositions and, accordingly, purposes, you need to know how to choose solder paste. The action consists in selecting the main substances of solder and the features of using flux. The texture of the material and its consistency have several advantages:

• spot application, ability to work with very small elements;
• using a medium-power soldering gun;
• application in cases where it is not technically possible to use conventional solders.

Many pastes are produced for industrial production, since their consistency makes it easy to dispense the material. The use of this substance is characterized by simple application, easy dosing, and fast speed of work. For home use, this type is also considered the most accurate, does not leave excess solder, and makes it easier for beginners to learn.

Composition features and benefits

Important! When choosing, lean towards buying branded certified products such as Kester R562 solder paste. The manufacturer ensures stable operation of the product, high technological characteristics, reliable wetting of contacts, consistency in batch composition, and compliance with the declared parameters, including volume and weight.

The choice of solder paste is based on its chemical composition, which determines the main technical characteristics of the seam (ductility, strength, t, etc.). According to the classification system, one of the conditions for separating the paste is the temperature regime at which the mixture “works.”

Brands for soldering printed circuit boards and connectors operate in the range of 180-300 °C, while paste for high-temperature soldering exceeds the threshold of 450-500 °C and can reach 1100 °C. Silver and copper can be used as the basis for its composition.

This may also selectively include:

Low-temperature soldering paste is made on the basis of tin, lead, with the additional use of antimony, which reduces the melting point to 90 °C. The main grades have the following composition: Sn63Pb37, Sn60Pb40, Sn62Pb36Ag2. Lead-free products contain copper as the main component and silver as an additional component. The following criteria are also determined by the components of the paste:

• The need to wash off residual flux. The substances used can be of 3 degrees of activity. The use of low-active fluxes (with a halogen content of up to 5%) makes it possible not to use a wash after soldering is completed when the product is operating under normal conditions.
• Solubility. Pastes, which are water based, can be diluted to different consistencies, depending on the shape of the structure and the desired results.
• halogens. The range of their content varies between 0-7%. These are active elements that, under difficult operating conditions (and even under normal conditions at high contents), cause oxidation of the surface, destroying the connecting layer. But thanks to their incomplete electronic formula, they are active when interacting with other elements.

Source: https://vmeste-masterim.ru/zachem-nuzhna-pajalnaja-pasta.html

Solder paste for soldering without a soldering iron - Metalworker's Handbook

Soldering is a simple matter, so many can do it without even holding a soldering iron in their hands. But there are times when this device is not nearby, but you need to solder something. This is where the dilemma arises, how to solder without a soldering iron, and whether it is even possible to carry out such a procedure without having the necessary tool or the ability to use it.

Many people have had moments in their lives when the wire in the charger, headphones, laptop power supply, or somewhere else broke or broke. What can be done in this case? How can I help myself fix the problem, at least temporarily, until I can solve the problem in a more rational and reliable way?

As it turns out, nothing is impossible. You can solder without a soldering iron. In the most unpredictable situations, it is always possible to solve the problem using improvised methods.

Necessary equipment

Of course, soldering without a soldering iron implies the presence of the most primitive tool and solder. It’s good if you also have rosin or acid, although in extreme cases just an aspirin tablet will do. Among the tools we can highlight:

• pliers;
• knife;
• foil;
• textile;
• solder paste;
• file or coarse sandpaper;
• source of fire.

It is not necessary to have all this together. Some tools can easily be replaced with what you have on hand. Instead of a file, you can take a knife , and sticks of the desired shape can successfully replace pliers. The main thing here is to turn on your imagination.

Tinning of parts

Whatever surface is offered for soldering, it is necessary to prepare it, that is, tin it. This will allow you to more reliably connect the parts together, and will also greatly simplify the process itself. To work you will need rosin (or soldering acid) and tin.

To carry out the tinning process, you will need a container where the solder and rosin will be melted. You can use a lid from iron cans, a small metal box, or something similar to a trough. Tin shavings are rubbed here using a file or sandpaper. It’s good if you have tin-lead solder - it’s more convenient to work with. If it is not there, then you will have to use rosin or acid.

Everything is clear with acid, just immerse the stripped edge of the wire in it, and then continue soldering. You will have to do the same with rosin as with tin, but it is not at all necessary to grind it off with a file. Its pieces can be large, since the melting point of rosin is much lower than that of tin, so even large pieces will have time to melt before the metal melts.

The container must be held over a fire source until the tin is completely melted. Next, the bare or stripped ends of the wire are placed first in rosin, and then in molten tin. When the result is satisfactory, that is, the exposed wire is well covered with a layer of metal, the container can be set aside.

If it is necessary to tin a flat-shaped part, then the algorithm of actions will be slightly different. Here, fine tin shavings and rosin are poured directly onto the surface of the part. Next, this part is heated , as a result of which the molten tin will evenly cover it. Remove excess with a rag or sandpaper.

Do not forget that when working with fire, iron parts will heat up, so you need to handle them with pliers or a rag to avoid getting burned. No one has canceled basic safety precautions.

Soldering wires

To solder small-section copper wires without a soldering iron, no complicated steps are required.

It is enough to simply twist the already tinned ends of the wire together, then use a match, lighter or other directed flame to warm them up well.

The solder left on the hairs during tinning is quite enough for them to be firmly connected to each other. After this, it is important not to forget to insulate the exposed areas with electrical tape, hot glue or another available method.

Wires of larger cross-section (up to 2 mm) can be soldered in a similar way. If there is not enough solder from tinning, then tin shavings are carefully placed on the twist, after which the soldered area is also heated. When the tin melts and fills all the voids between the wire hairs, soldering can be stopped. But don’t forget to insulate the exposed area.

If you need to solder a wire to a flat part or connect two parts of a flat shape to each other, then you need to pour crushed solder onto the tinned place, then attach the wire and heat the parts until the tin is completely melted. In the case of two flat parts, the tinned surface is also covered with pieces of tin, another flat part is placed, they are compressed and heated.

Connection with groove

You can solder without a soldering iron in another interesting way. To implement this, you need a small piece of thick foil. This method allows you to solder fairly thick wires with a cross-section of up to 3 millimeters. This method is also interesting because it does not require pre-tinning.

First, you need to strip the ends of the wires by about 30 mm, and securely twist the exposed parts together. Now a small rectangle is cut out of the foil of such a size that the prepared ends can be completely covered with it. Foil is wound onto the wires in the form of a funnel, into which small pieces of rosin and tin shavings are poured. The ends of the groove are twisted to prevent the contents from spilling out.

Now the resulting structure must be heated until the tin and rosin melt. After this, all that remains is to wait for the soldered parts to cool down. The remaining foil is removed and, if necessary, the weld area is treated with a file, needle file or emery cloth. This method is perfect when you need to quickly and without tools solder wires in the field.

Cooking pasta

You can solder without a soldering iron using solder paste. Having prepared such a solution, you can connect not only wires and flat elements, but also some radio components, and also solder the wire to the board without a soldering iron.

To make solder paste, you will need to mix 32 ml of hydrochloric acid with 12 ml of water. 8.1 g of zinc is added to the resulting solution, and after dissolving it, another 7.8 g of tin. All this is done in glass or enamel containers. When the reaction is complete, all that remains is to evaporate the water to form a paste-like mixture.

Now another 7.4 g of lead, 14.8 g of tin, 10 ml of glycerin, 7.5 g of dry ammonia, 29.6 g of powdered zinc and 9.4 g of rosin should be added to the paste. All components must first be heated and brought to a dusty state.

When the composition is ready, it can always be used for its intended purpose. It is preferable to store the paste in a tightly closed glass container. Soldering with this composition is extremely simple:

1. The areas of parts to be soldered are cleaned.
2. Using a brush, apply a thin layer of paste to the joints.
3. The area where the parts are to be welded or soldered is heated with a candle, lighter or other method. It is highly preferable to use a turbo lighter or a gas torch with a directed flame. However, in their absence, any source of open fire will do.

In this way, it is quite possible to solder almost any parts and wires at home without a soldering iron, but the process of making the solder paste itself can be intimidating. But there is a much more attractive alternative - solder paste can be bought ready-made.

For soldering very small parts and thin wires, it is preferable to make solder paste with a slightly different composition . It will contain the following ingredients:

• 7.4 g lead powder;
• 7.3 g of zinc in dust form;
• 14 g glycerin;
• 4 g rosin;
• 14.8 g of powdered tin;
• 10 ml diethyl ether.

All components are mixed to a paste. Instead of diethyl ether, you can use 10 ml of rosin dissolved in glycerin. Using this tool, it becomes possible to solder a wire or part onto the board.

Homemade soldering jig

You can make a soldering iron from a candle or lighter. True, it is better to take the latter from good heat-resistant plastic, since a disposable Chinese device will not work for even a minute, and the metal device can get very hot. You will also need a piece of thick copper wire with a diameter of 3 to 5 millimeters and some thin wire for winding to the lighter.

  How to choose a gas torch for soldering

The thick wire must be completely stripped of insulation, and then bent so that one part can be wound to a lighter or candle, and the opposite end is above the flame for constant heating. Such an improvised tip is capable of soldering even small parts (down to the tiniest resistors). True, you can’t do without tin and rosin. To make work more convenient, it is preferable to sharpen the working area of ​​the tip.

Alternative Repair Methods

If a wire is broken and you urgently need to restore it, at least for a short time, then there are faster alternatives. True, without soldering, but quite capable of helping in emergency situations.

So, a broken wire can simply be cut at the break point and simply twisted together. It is important here not to confuse the polarity, since chargers have a constant voltage. It wouldn't hurt to insulate the twists either.

You can temporarily attach a wire with a flat surface. To do this, just tightly attach one part to the other and fill it with molten plastic. Such restoration will be sufficient if you use the resulting connection carefully and briefly.

No matter what happens, you can always find a way out of the current situation if you turn on your fantasy and imagination. Sometimes this will not help to repair the device, but it will allow you to urgently restore its functionality for a short time.

Source: https://ssk2121.com/payalnaya-pasta-dlya-payki-bez-payalnika/

Types and methods of applying solder pastes

The quality of electronic equipment largely depends on the strength of the connection between circuit components and printed circuit boards. Good soldering is ensured by solder paste. This mixture serves several functions.

Characteristics

The paste-like mass contains solder, fixing agents and flux. To create consistency, solvents, stabilizers, substances to maintain stable viscosity, and activators are added to the paste.

The solder component can be represented by eutectic alloys of lead and tin, the content of which is 62-63%, with or without the addition of silver. Sometimes solder is represented by lead-free alloys of tin (95.5-96.5%) and silver with or without copper additives.

The size of the particles of the viscous mass is of great importance, depending on which a stencil or solder paste dispenser should be used for application. Both methods can be implemented without a soldering iron.

If the particles are round in shape, you can use both a stencil and a dispenser. Spherical grains are usually obtained due to the atomization of the solder component during the production of solder paste.

The size and shape of the particles cause possible difficulties in application.

Solder paste with very small particles due to the large surface area in contact with air can oxidize quickly. Small grains can form solder balls. Very large round particles and grains of irregular shape tend to clog the stencil.

According to the size and shape of the particles, solder pastes are divided into 6 types. The choice must be made taking into account the output step and the size of the stencil windows.

Flux as a component of solder

Flux components are also subject to classification. There are 3 types of fluxes in solder pastes:

• rosin;
• water-washable;
• no-wash.

The rosin group of fluxes is represented by activated, moderately activated and completely non-activated compositions. Soldering fluxes that have not been activated show the least activity.

The most widely used fluxes are those with medium activity. They clean the surface well, spread over it, and wet the parts to be joined. However, they can cause corrosion. Therefore, after soldering, the working area must be washed with special solvents or hot aqueous solutions.

Soldering fluxes that have undergone significant activation are used for heavily oxidized parts. After soldering, the workplace is washed with organic mixtures with alcohol.

Water-washable flux compositions are based on organic acids. They are highly active and contribute to the formation of a good seam, but require mandatory washing with purified hot water.

No laundering is required when working with fluxes made from synthetic or natural resins. Even if there are residues on the surface after soldering, this will not harm the product.

The residue does not conduct current and is resistant to oxidation. It does not need to be washed. If desired, washing can be done with special solvents or hot aqueous solutions.

Rheological features

Important characteristics of surface mount solder pastes are viscosity, adhesiveness, durability, and the ability to create a three-dimensional connection on the board.

Knowledge of quantitative indicators of rheological properties allows you to choose the right printer for applying solder paste, which can rationally dispense portions.

The paste is applied taking into account the tendency to increase the viscosity of the paste mass. A decrease in viscosity occurs with increasing temperature. To successfully solder with solder paste, you need to periodically add new portions to the mass and monitor the temperature readings in the working area. This can be easily done using screen printing machines equipped with thermal sensors.

Many packages of imported pastes indicate “lifetime”. The value determines the time interval from the moment the can is unsealed until the end of soldering, during which the rheological properties will remain unchanged.

If the indicator is low, you will have to work quickly to obtain a high-quality connection. Now there are mixtures on sale with a “lifetime” of 72 hours. You can work slowly with such tools.

An important characteristic is the stickiness of the solder paste, which reflects the ability of the part to stay on the board before starting work.

Some pastes can fix electronic components for more than a day, which is convenient when installing large boards. Compositions with low adhesiveness are capable of holding the element for 4 hours.

There is a wide range of solder pastes on sale, some of which are sold in a syringe for manual or automatic dispensing, others in cans or cartridges.

Products in cans are intended for screen printing machines. They are made of metal sheets with great scrupulousness, which makes it possible to cut out cells on the board for applying solder paste with an accuracy of 0.1 mm.

Special types of stencils can regulate the thickness of the paste-like mass. The machines can operate in both manual and automatic modes. Expensive models are additionally equipped with a stencil cleaning system, which significantly increases work productivity.

Storage conditions

Multi-component solder mixtures are influenced by external factors. The conditions required for proper storage are indicated on the packaging. They should be read and strictly followed.

Be sure to indicate not only the temperature suitable for storage, but also the range of its possible deviations.

Usually, when the storage temperature exceeds 30℃, the mixture will deteriorate irreversibly. Very cold environments may impair the performance of activators contained in solder or thermal paste.

The time it takes for the paste to reach room temperature is of great importance. It is important to know:

• how long it needs to be stirred;
• what temperature and air humidity should be maintained when using the paste;
• how long it can be stored under the specified conditions.

When the air is humid, solder balls may appear in the solder mass due to water absorption. The shelf life and storage conditions of solder pastes differ and depend on the composition. If you follow the manufacturers' instructions, the quality of soldering will meet your expectations.

For plumbing systems

A completely separate group consists of paste-like compositions intended for installation of fittings made of copper and its alloys in water supply systems with a soldering iron. These compositions are subject to special requirements, which are strictly regulated by GOST.

None of the paste components can be toxic. The flux must completely prevent oxidation of the seam and the penetration of corrosion products into the water.

Water supply pastes are completely unsuitable for working with electronic circuits for many reasons, in particular because copper or silver is often added to them to increase the strength of the connection. Such compositions are not used in electronics.

Source: https://svaring.com/soldering/pripoj/pajalnye-pasty

ХарактеристРеРєРё РїР°СЏР»СЊРЅС‹С РїР°СЃС‚: что нужно знать?

РўРµСологоЏ поверСностного RјРѕРЅС‚ажа весьма сложна, РЅР° качество пайки SЌР»РµРєС‚СЂРѕРЅРЅС‹С РјРѕРґСѓР»РµР№ РІР» RёСЏРµС‚ множество СЂР°Р·Р»РёС‡РЅС‹С С„Р°РєС‚РѕСЂРѕРІ.

Так, надежность RєРѕРЅРµС‡РЅРѕРіРѕ изделия SЃРёР»СЊРЅРѕ заввисит РѕС ‚ качества используемой паяльной пасты.

СтатистРеРєР° показывает, что РґРѕ 64% дефектов РІРѕР·РЅРёРєР° ет еще РґРѕ поступления РїРµС ‡Р°С‚РЅС‹С РїР»Р°С‚ РІ установщик RєРѕРјРїРѕРЅРµРЅС‚РѕРІ.

R'ведение

Подавляющее большинство дефектов (СЂРёСЃ. 1) РІРѕР·РЅРёРєР°РµС ‚ РЅР° этапе нанесения паяльной РїР° SЃС‚С‹.

Например, может произойти SЂР°Р·Р±СЂС‹Р·РіРѕРІР°РЅРёРµ RїСЂРёРїРѕСЏ РѕР±С ЂР°Р·РѕРІР°РЅРёРµ его S€Р°СЂРёРєРѕРІ РІРѕРєСЂСѓРі RєРѕРјРїРѕРЅРµРЅС‚РѕРІ, Р° расслоение флюса обычно РїСЂРёРІРѕРґРёС‚ Рє РїСЂРѕ±Р»РµРјР°Рј РІ работе РїРµС‡Р°С‚РЅС‹С РіРѕР»РѕРІ закрытого С‚РеРїР° РІ С‚СЂР°С„Р°СЂРµС‚РЅС‹С РїСЂРёРЅС‚РµСЂР°С.

RS‚Рѕ значит, что СѰрактеристикам используемой паяльРSРѕР№ пасты Рё самому процессу нанесения необСрѕРґРёРјРѕ SѓРґРµР»СЏС‚СЊ больше РІРЅРёРјР° РЅРёСЏ

R RyoSЃ. 1. RџСЂРёС‡РеРЅС‹ пэтапы RїРѕСЏРІР»РµРЅРІРґРµС„ектов RїР°Р№РєРё RєРѕРјРїРѕРЅР µРСтов

RџСЂРё РѕЃРїРѕР»СЊР·РѕРІР°РЅРЅРёР·Р°РєСЂС‹С‚РѕР№ RіРѕР»РѕРІС‹, RїСЂРё SЂР°Р±РѕС‚Рµ SЃ RєРѕРјРїР ѕРЅРµРЅС‚ами СЃ ультрамалы Рј шагом выводов Рј высокой SЃРєРѕСЂРѕСЃС‚Рё нанесения RїР°СЏР»СЊР SРѕР№ пасты, РїСЂРё стремлении добиться ее Р±РµР·РґРµС „ектного нанесенои РїСЂРё РїСЂРё ппользовании Р±РµСЃСЃРІРёРЅС†РѕРІС ‹С РїР°СЏР»СЊРЅС‹С РїР°СЃС‚ необСрѕРґРёРјРѕ RїРѕРЅРёРјР°С‚СЊ, как RїРѕРІРµРґРµС‚ себ "СЏ материаР". ХарактеристРеРєРё пасты неободимо изучать, начРеная СЃР * стадии производства Рё РґР° лее — РЅР° СЌС‚Р°РїР°С РїРµСЂРµРІРѕР·РєРё, Сранения, РІРѕ время РЅР°СрѕР¶РґРµРЅРёС Џ РЅР° трафарете Рё затем РЅР° печатной плате РґРѕ момента ее RїРѕРїР°РґР°РЅРёСЏ РІ установ S‰РёРє компонентов. Обычно паяльная паста демонстрирует стабильносS ‚СЊ РІРѕ время перевозки, С‡СѓРІСЃС‚РІРёС‚РµР»СЊРЅРѕСЃС ‚СЊ Рє температуре РІРѕ время нанесения, различное «РїРѕР» ІРµРґРµРЅРёРµ» РІ заввисимости РѕС‚ SЃРєРѕСЂРѕСЃС‚нанесения, разное RІСЂРµРјСЏ SЃРѕСранения SЃРІРѕР№СЃС‚РІ РЅР° трафарете (РїСЂРё нанесенРёРё СЃ помощью ракелей) Рё неодинаковые SЃРІРѕР№СЃС‚РІР° клейкости.

РќР° сам же процесс нанесения влияет RјРЅРѕР¶РµСЃС‚РІРѕ S„акт РѕСЂРѕРІ. RќР° SЂРёСЃ. 2 РѕРіРѕ процесса.

RћS‡РµРІРёРґРЅРѕ, неободимо SѓРґРѕСЃС‚овериться, что RєР»СЋС‡РµРІР ѕРµ звено S‚есслого‡РµСЃРєРѕРіРѕ процесса РЅРµ RјРµРЅСЏРµС‚ СС°СЂР°РєС ‚еристики РїР °СЏР»СЊРЅРѕР№ пасты РІ Судшую сторонСГ.

Если поставлена задача повысить процент выпуска Рі " едоь Р·Р° вязкостью, прочностью РЅР° SЃРґРІРёРі Рё РїСЂРѕРґРѕР»Р¶РёС ‚ельностью СЃРѕСранения SЃРІРѕР№СЃС‚РІ РЅР° трафарете.

R RyoSЃ. 3. паяльной пасты

Хорошая паяльная паста — это РЅРµ просто SЃРјРµСЃСЊ РїСЂРёРїРѕС Џ, флюса добавок, С„РѕСЂРјРёСЂСѓСЋС‰РёС СЂРµРѕР» RѕRіРёС‡РµСЃРєРёРµ SЃРІРѕР№СЃС‚РІР° RїР°СЃС‚С‹.

РќРµ менее важно рассматривать SЃРѕРІРѕРєСѓРїРЅРѕСЃС‚СЊ (взаимодействие) SRеРјРёС‡РµСЃРєРёС Рё С„РёР·РёС‡РµСЃРєРёС СѰрактерисS ‚РёРє материалов: небольшие SЂР°Р·Р»РёС‡РёСЏ РІ составе вещест РІ, особенности РѕРєСЂСѓР¶Р°СЋС ‰РµР№ среды (например, температура, RІР»Р°Р¶РЅРѕСЃС‚СЊ) Рё услоРІРёСЏ тесслогЃческого процесса РјРѕРіСѓС‚ сущест венно повлиять РЅР° «РїРѕРІРµРґРµРЅРёРµ» паяльной пасты.

RќР° SЂРёСЃ. 3 СЃСематически показано влияние СѰрактеристик паяльн РѕР№ пасты РЅР° качество RєРѕРЅРµС‡ РЅРѕРіРѕ изделия.

RS‚Рѕ упрощенная сема, демонстрирующая лишь РЅРµРєРѕС‚РѕС ЂС‹Рµ РІР·Р°Ремосвязанные факторы. РќР° самом же деле такие взаимосвязи есть RјРµР¶РґСѓ всеми СЃР ѕСЃС‚авляющими.

RќР°РїСЂРёРјРµСЂ, SЃРєРѕСЂРѕСЃС‚СЊ RѕRєРѕР»РµРЅРёСЏ RїРѕСЂРѕS€РєР° RІРѕ RјРЅРѕРіРѕРј RѕРїСЂ еделяется размером Рё S„РѕСЂРјРѕР№ его S‡Р°СЃС‚РёС†.

R RyoSЃ. 3) °СЏР»СЊРЅРѕР№ пасты РЅР° качест РІРѕ ее нанесенго качество RєРѕРЅРµС‡РЅРѕРіРѕ продукта

ХарактеристРеРєРё, связанные СЃ чувствительностью R їР°СЏР»СЊРЅРѕР№ пасты Рє температуре, качеством нанесения РїСЂРё SЂР°Р·Р»РёС‡РЅРѕР№ SЃРєРѕСЂРѕСЃС‚Рё, РїСЂРѕРґРѕ лжительностью СЃРѕСранения свойств РЅР° тра S„арете, вязкостью RјРѕР¶РЅРѕ RѕР±СЉСЏСЃРЅРёС‚СЊ СЃ S‚очки R·СЂРµРЅРёСЏ S ЃРІРѕР№СЃС‚РІ S‚екучести Рё деформации паяльной пасты.

Реология паяльной пасты

Реология — это наука, которая занимается изучением SR° SЂР°РєС‚еристик S‚екуS‡РµСЃС‚Рё Рё деформации вещества.

Касательно РїР°СЏР»СЊРЅС‹С РїР°СЃС‚ важео пзучение SЌС‚РёС РєР°С‡РµСЃС ‚РІ РїСЂРё воздействии Р° S‚мосферного давления, вибрации SЂРµРјРЅРµР№ конвейерноР№ системы (расползание) Рё СЃРёР», СЃРІСЏР·Р°РЅРЅС‹С СЃ процессом нанесения паяльной пасты (перекатыва РЅРеРµ валика пасты). Различные SЃРёР»С‹, воздействующие РЅР° материал, — это SЃРёР»Р ° SЃРєРѕСЂРѕСЃС‚Рё SЃРґРІРёРіР ° Рё сила касательного напряження СГРґРІРёРіР°. РљСЂРѕРјРµ SЃРёР» СЃРґРІРёРіР°, деформации Рё S‚екучести паял СЊРЅРѕР№ РїР °СЃС‚С‹, Р° также SЃРєРѕСЂРѕСЃС‚Рё восста новления ее SЃРІРѕР№СЃС‚РІ, важны время Рё S‚емпература.

Таким образом, РІРѕРїСЂРѕСЃ Тзучения RїРѕРІРµРґРµРЅРёСЏ RїР°СЏР»СЊРЅРѕР№ РїР° сты обычно упрощался, Рё РІРѕ внимание RїSЂРёРЅРёРјР°Р»РёСЃСЊ S‚акие арактеристики, RєР°Рє вязкость І РѕРґРЅ РѕР№ точке Рели кривая вязкости. Р'язкость — это сопротивление ньютоновскому S‚РµС ‡РµРЅРёСЋ.

Р' зависимости РѕС‚ СѓСЂРѕРІРЅСЏ SЃР»РѕР¶РЅРѕСЃС‚Рё, RѕР±РѕСЂСѓРґРѕРІР°РЅРёРµ, РёСЃР їРѕР»СЊР·СѓРµРјРѕРµ для определения SЂРµРѕР»РѕРіРёС‡РµСЃРєРёС СС°СЂР°РєС‚РµСЂРёС ЃС‚ РёРє, может определить вязкость RїР°СЏР»СЊРЅРѕР№ пасты Р·Р° счет высчитывания РІСЏР·РєРѕСЃС ‚Рё РІ РѕРґРЅРѕР№ точке Рё предела S‚екучести построения R єСЂРёРІРѕР№ вязкости.

R' SЂРѕС‚ацРеРѕРЅРЅРѕРј RІРѕРєРєРѕР·РёРјРµС‚СЂРµ R'руквилда RѕS‡РµРЅСЊ RјР°Р»РµРЅСЊ кая площадь поверССости. " ьтатов измерений существенно RѕРіСЂР°РЅРёС‡РµРЅР°.

Спиральный впкозиметр RњР°Р»РєРѕРјР° отличается SѓRјРµСЂРµРЅ РЅРѕР№ повторяемостью РїРѕР»СѓС‡Р°РµРјС‹С РёР·РјРµСЂРµРЅРёР№ .

Р' РІРІРёСЃРєРѕР·РёРјРµС‚СЂР°С С‚РеРїР° пластина-пластина точность РІС‹ ше, Р° Р·РСР°С ‡РёС‚, больше возможностей проверять воздействие РѕС ЃС†РёР»Р»СЏС†РеРё, суперпозиции S‚емперат SѓSЂ Ryo S‚. Рґ. Различные S‚РеРїС‹ RІРёСЃРєРѕР·РёРјРµС‚СЂРѕРІ RјРѕР¶РЅРѕ RІРёРґРµС‚СЊ РЅР° SЂРёСЃ. 4.

R RyoSЃ. 4. RўРёРїС‹ RІРёСЃРєРѕР·РёРјРµС‚СЂРѕРІ

Сейчас особенно RїРѕРїСѓР»СЏСЂРЅС‹ SЃРїРёСЂР°Р»СЊРЅС‹Рµ РІРѕуРєРѕР·РёРјРµС‚С ЂС‹. RћРЅРё завоевали репутацию RѕР±РѕСЂСѓРґРѕРІР°РЅРІРЏ, позволяющегР* получить более S‚очные RїРѕРєР °Р·Р°РЅРёСЏ.

Р'СЃРµ С‚РеРїС‹ прошли сертификацию РЅР° RїРѕР»СѓС‡РµРЅРёРµ большинсS ‚РІР° РјРµР¶РґСѓРЅР°СЂРѕРґРЅС‹С СЃС‚Р°РЅРґР °СЂС‚РѕРІ.

Р'олее SЃР»РѕР¶РЅРѕРµ оборудованве S‚РеРїР° RїР»Р°СЃС‚РеРЅР°-пластина РґР ѕР»Р¶РЅРѕ использоваться гораздо более квалквалкваловалом РІ Рј персоналом РІ лаборР°С‚РѕСЂРЅС‹С СѓСЃР»РѕРІРёСЏS.

позволяет S‚очно S‚еристики вязкости паяльной пасты . Его модульный дизайн обычно RїРѕ·РІРѕР»СЏРµС‚ наращивать І озможности отсР»РµР¶РёРІР°РЅРІР»РёС‡РЅС‹С СЂРµРѕР»РѕРіРѕС‡РµСЃРєРёС РїР°СЂР°РјРµС‚СЂРѕРІ, РЅРµРєРѕС ‚орые РёР· РєРѕС‚РѕСЂС‹С РѕС‚РЅРѕСЃСЏС‚СЃСЏ SЃСѓРіСѓР±Рѕ Рє действию РѕСЃС†Релляции.

Сравним данные вязкости РІ РѕРґРЅРѕР№ точке. Таблица показывает, что данные, полученные СЃ РїРѕРјРѕS ‰СЊСЋ разного РѕР± орудованкя, практически несравнимы.

Таблица. Р'язкость паяльной пасты РІ РџР°*СЃ

Система

R'искозиметр RњР°Р»РєРѕРјР°, RєРѕРЅС‚ролккЃемая SЃРєРѕСЂРѕСЃС‚СЊ SЃРґРІР ёРіР° РїСЂРё 6 СЃ-1

Source: https://www.tech-e.ru/2009_8_28.php

Notes from a programmer

The J-antenna, also known as the J-pole, is a popular antenna among radio amateurs, typically used on VHF. I recently decided to make a J-antenna for 2 meters, simply because I've never made one before. At the same time, it was decided to try a new material for me, copper pipes.

Theory

The shape of the J-antenna really does not resemble the Latin letter J:

In fact, a J-antenna is a vertical dipole fed from below. The upper part is an antenna sheet with a length of λ/2, that is, a dipole. The lower part of the antenna is the matching section. It is a two-wire line with a length of λ/4.

The coaxial cable is connected to the antenna at some point in this section, as shown in the picture.

This ensures matching of a coaxial cable, which has a characteristic impedance of 50 Ohms, and a dipole, which, when powered from the edge, has a high resistance of several thousand Ohms.

Why does such a scheme agree on anything at all? To answer this question, consider two edge cases. Let's say we decide to feed the J-antenna at the very bottom of the matching section.

The question is, what is the input impedance of the antenna at this point? It is not difficult to guess that here we have a short circuit, that is, a resistance of 0 Ohm. Okay, now let's move up λ/4 and try to power the antenna here.

What input resistance will we see? It turns out that it is infinitely large, since the λ/4 section is nothing more than a quarter-wave transformer with 0 ohms at the end.

Intuition suggests that somewhere between these two extremes you can find any active resistance, at least 50 Ohms, at least 75 Ohms, at least any other. And indeed, in practice this is exactly what happens.

Practice

It was decided to make the antenna from copper pipes with a diameter of 10 mm. I've never soldered copper pipes before. As it turns out, it's not that difficult:

You will need the following tools: a vice, a gas cylinder, a gas torch, soldering paste for copper pipes, gardening gloves, a round file. Optionally - lead-free solder, pipe cutter. Pipes are easy to cut, so if you don't have a pipe cutter, a hacksaw, Dremel, or something like that will do. Plumbers only use lead-free solder because lead is toxic. But we are not going to pump water through pipes, so the good old POS-61 will do.

The following materials were used in the antenna: SO-239 connector, some thick copper wire, a copper pipe with a diameter of 10 mm (at least 2 meters, better with a margin), two 90° angles and two couplings for it, as well as some epoxy glue.

Soldering is carried out as follows. Solder paste is applied to the soldering site, and the corresponding fitting is put on - an angle or a coupling. Heat with a gas burner until the paste becomes a characteristic silver color.

This means that the optimal temperature has been reached. We move the burner to the side and poke a little solder into the soldering area. It should melt right away. Turn off the burner and wait for the copper to cool.

In words it is most likely not very clear, but you will find a lot of videos about how this is done.

Important! Be extremely careful with the gas burner. The gas combustion temperature in it is about 1000°C.

The antenna dimensions are not very critical. In our case, the wavelength λ is equal to:

>>> 300_000_000/145_000_000
2.0689655172413794

I took exactly 2 meters. The distance between the conductors in the matching section is about 1-3% of λ. I used a piece of pipe 4 cm long at the bottom of the antenna. After soldering the corners, the total distance was 6 cm:

The couplings are soldered to the SO-239 connector as in the photo and put on the pipes. In order for the couplings to slide along the pipes, they need to be slightly processed from the inside with a file. We carry the antenna to a future location for permanent installation. Personally, I placed it on the balcony, attaching it with nylon ties to a PVC pipe. Then we match the antenna by moving the couplings along the matching section.

In my case, the EU1KY analyzer showed perfect agreement:

We go to the local repeater and make sure that the correspondents receive us well. All that remains is to solder the couplings in this position, seal the remaining holes in the pipes with epoxy, add a shut-off choke, and the antenna is ready!

Conclusion

Some radio amateurs report that the J-pole also works in the 70 cm range, at the third harmonic. I was able to adjust the above antenna normally only in the range of 2 meters, at 70 cm everything is very bad. Even if you manage to tune the antenna to two bands simultaneously, at 70 cm its radiation pattern will leave much to be desired. It’s also not very clear what to do with the cut-off throttle. In other words, you should not expect multi-band performance from a J antenna.

Have you ever made a J-antenna or perhaps related ones (Slim Jim, Super-J), and if so, what materials did you use?

Source: https://eax.me/j-pole-antenna/

Soldering with solder paste

Soldering of parts to the surface of a printed circuit board is carried out mainly using solder paste. The composition of pastes can vary greatly, but basically the main components are solder, flux and binder. Any soldering paste looks like a thick and viscous mixture of chemicals.

Special qualities of materials for soldering

It is known that connecting elements by soldering is possible when using a material with a lower melting point. For simple amateur circuits, solder is still used together with flux or acid. The paste, which contains both components, as well as various additives, significantly speeds up the process of soldering complex printed circuit boards with SMD elements. Widely used in electronics production.

Let's look at the main components of soldering paste:

• powdered solder of different crushing qualities;
• flux;
• binding components;
• various additives and activators.

Various alloys with tin, lead and silver are chosen as solder materials. Recently, lead-free solder pastes have become the most popular.

Each solder paste contains flux, which acts as a degreaser. In addition, an adhesive binder is required, which facilitates the installation and fixation of SMD components on printed circuit boards. The larger the board size and the higher the elemental density, the more important it is to use more viscous solder pastes.

The shelf life of the paste has a big impact on the quality of soldering of SMD components. Since the composition usually contains active chemical components, its use and storage period is very short, no more than 6 months. During storage and transportation, it is necessary to maintain the temperature from +2 to +10. Only if all conditions are met, high-quality soldering is possible.

Variety of solder pastes

Depending on the use of various components, there are several types of solder pastes:

• washing;
• without washing;
• water soluble;
• halogen-containing;
• halogen-free.

The properties vary depending on the use of the flux included in its composition. Any paste that is not washed off with water contains rosin. To wash products from such a paste, you must use a solvent.

The general rule for contained elements and SMD components is that the better the solderability, the lower the reliability. Maintaining a compromise between these important properties is the key to effective functioning. The use of halogen-containing pastes significantly increases manufacturability, but somewhat reduces reliability.

Methods of using soldering pastes

In order to obtain a high-quality and reliable connection of SMD elements on a printed circuit board, you must perform certain actions:

• high-quality cleaning and degreasing of the printed circuit board followed by drying;
• fixing the board in a horizontal position;
• uniform and thorough application of solder paste to joints;
• installation of small and SMD elements on the surface of the board; for more reliable soldering, it is recommended to additionally apply paste to the legs of the microcircuits;
• when the board is heated from the bottom, the hair dryer is turned on and the upper part with the installed elements is heated with a gentle flow of warm air;
• after the flux has evaporated, the temperature of the hair dryer increases to the melting temperature of the solder;
• the soldering process is visually controlled;
• After cooling, the final washing of the printed circuit board is performed.

Basic tricks of high-quality soldering

In order to efficiently connect elements using soldering paste, you should take care of some points. First of all, it is important to clean and degrease the board, especially if oxides are noticeable, or the board has been lying unused for a long time. In this case, it is advisable to tin all the contact pads with low-melting solder.

Solder paste should have a convenient consistency. That is, it should not be too liquid or too thick. A “sour cream” structure is most suitable, as it will wet the surface well. Wettability plays a huge role in the reliability and quality of the solder joint.

When soldering SMD elements, it is important to apply a thin layer of paste. A thick layer can short-circuit the pins of the microcircuits. Soldering simple elements does not imply such subtlety.

If the printed circuit board is of significant size, it is advisable to use bottom heating with a hairdryer, iron or special means at a temperature of 150 degrees Celsius. If this is not provided for, the board may warp.

Excess and remnants of solder can be easily removed with a soldering iron with a variety of attachments. For example, to remove residues of substances used for soldering between the legs of microcircuits, it is convenient to use a “wave” tip.

Source: https://rem-serv.com/payka-s-pomoschyu-payalnoy-pasty/

What is solder for?

Solder is a material, metal or alloy based on it, used for reliable connection of parts, melting at a lower temperature than the metals it solders. In the production of solder, alloys of lead, silver, tin and other soft metals are most often used.

The solder joint serves for a long time under favorable operating conditions of the materials being soldered and does not tolerate vibration, dynamic pressure and tensile loads. Also, the aggressive environment significantly affects the reduction in the service life of solder joints.

For ease of soldering, solder is produced in a wide range: wire, rod, powder, paste and other designs.

Purpose and types of solder

So what is solder for? Soldering is carried out to create a strong connection between mating parts or workpieces, less often to achieve the tightness of containers and pipelines, or to maintain a more reliable electrical contact with a low transient current resistance.

As mentioned above, the melting temperature of the solder is lower than the melting temperature of the parts being joined, then the integrity and structure of the soldered workpieces does not change. Only the solder melts, enveloping the workpieces being fastened. When hardened, the parts are securely fastened and the connection is ready for use.

Solder in production is selected depending on the physical and chemical properties of the metals being soldered, corrosion resistance, conductivity and other factors, taking into account the effective cost of the operation.

Solders are divided into soft and hard. Soft ones melt already at T = 300 C, and melting of hard grades of solders occurs at much higher temperature values. The strength of soft brands of solders is much lower and ranges from 16 to 100 MPa. As for hard solders, their strength range is 100-500 MPa.

Solder materials

Soft grades of solder are made from tin with the addition of zinc, lead, cadmium, etc. Recently, in order to protect working conditions and preserve the environment, solders without harmful metals are more often used, which in addition to tin contain bismuth, copper, silver and other metals.

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Of the hard solders, the most famous in production are silver and copper-zinc with the use of additives. Silver solders have received a very wide range of applications, which in particular serve as a good assistant for soldering products and blanks made of non-ferrous metals and in the jewelry industry.

Lead-free solders

The simplest and most understandable lead-free solder is ordinary tin. Wire made of this metal is found in almost every home where there is a soldering iron. Often, when producing tin wire, an additional derivative of coniferous tree resin, called rosin, is introduced inside as a flux. This solution is practical and helps in work and reduces soldering time.

However, ordinary tin has very limited applications. For example, this is soldering of various equipment. In general, the use of tin solder is not possible, despite its excellent electrical conductivity.

This is all due to the tin plague, the growth of “whiskers” and other risk factors when soldering with tin. The introduction of other metals helps solve this problem. Tin is often mixed with silver, copper and even gold. However, in this case, hard solder alloys are formed that have significantly high temperature characteristics. Therefore, in order to improve fluidity, fluxes are used.

Unfortunately, at present, lead-free solders, despite the positive environmental component and safe work, are not a full-fledged alternative to tin-lead solders.

Solder pastes

Thanks to the development of new technologies and the increasing scale of growth in the production of electronic circuit boards, solder pastes began to be used as a soldering element. The paste is made from several components: powdered solder, flux and a binder. This fine mixture is used in manual and screen soldering.

For soldering radio electronics, pastes contain tin and alloying components to improve the quality of the connection. The properties of ductile solder are significantly affected by particle size. The most common pastes are those with particle sizes in the range of 25-45 microns. Since this technology is used more for stencil soldering than for hand soldering, pastes must meet established requirements for reliable mating of elements.

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The criteria for good quality are the shape of the particles, which are spherical after grinding. Solder pastes are also susceptible to the harmful effects of carbon and hydrogen. Therefore, contact with air from the manufacturing stage to operation should be minimized.

In screen printing production, solder pastes are filled into special 500 gram containers. They are not practical for home use, so for your own purposes this mixture can be purchased in syringes of various capacities. The storage conditions for such pastes are low temperature, so the ideal place for storage is a regular refrigerator. At normal and high temperatures, the paste quickly begins to separate.

Rosin

I would like to pay special attention to the most common flux, which is often used at home. Rosin, as mentioned earlier, consists mainly of resin from coniferous trees. It is mainly used in the solid state, but is also available in gel and liquid form.

Rosin removes oxide deposits well even at low temperatures, which is undoubtedly its advantage. The material is a dielectric, but this does not in any way affect the electrical conductivity of the soldering materials. It is used for almost all types of soldering, is not exposed to moisture, is not toxic to humans and is generally available because it is low in cost.

This article helped the inquisitive reader understand why solder is needed and even deepen his knowledge in the field of soldering and the use of various methods of its application for industrial and home purposes. All that remains is to purchase a soldering kit and create for the purpose of fixing the material and household needs.

Source: https://pochemu24.ru/tekhnika/dlja-chego-nuzhen-pripoj/