How to do resistance welding at home

How to make resistance welding with your own hands

Contact welding is one of the most technologically advanced, but at the same time simple methods of joining metal parts. It is used both in large-scale production and in everyday life. This type of welding is thermomechanical, since high temperature and mechanical pressure are used simultaneously to join metals. Airplanes, ships, cars and microcircuits are assembled using resistance welding. Factories usually use large, powerful machines.

Manual resistance welding is also quite feasible. To do this, home craftsmen use homemade resistance welding machines, since their production does not take much time and saves money.

Homemade devices are used both at home and in small private workshops. In this article we will tell you what the contact welding method is and how it is used to weld stainless steel or any other metal.

We will also teach you how to assemble a resistance welding machine with your own hands.

general information

Resistance welding (also "electric resistance welding", "electric resistance welding" or "ERW") is a method of joining metals by heating them with current and simultaneously mechanically deforming them with pressure.

In simple terms, a weld is created by heating the metal and then compressing it under two thick metal electrodes. When resistance welding, it is the current, not the pressure, that plays the key role.

Below is a diagram of the simplest resistance welding.

During the passage of current during welding, heat spreads through the metal part, in the weld area, and also between the metal electrodes. In this case, all these elements are heated at different temperatures; the highest concentration of heat is observed when contact is established between the electrodes and the part.

If the device is configured correctly and the welding technology is followed, then the metal surface should not heat up too much, since in resistance welding it is not so much the high melting temperature that is important, but the combination of temperature and mechanical action. In addition, the electrodes must be cooled (for example, with water). So it is important to monitor the heating temperature. If it is excessive, then this is the first sign of a welder error or faulty equipment.

Advantages and disadvantages

Resistance welding has quite a lot of advantages, thanks to which it has become so popular recently. First of all, this welding method consumes very little energy with high productivity. After all, the contact connection method is very fast and it takes less than a second to form one weld point. The quality of the resulting seams is at a high level, the connections are strong and durable.

No special knowledge is required; resistance welding can be done by a master without special qualifications. It is also possible to fully automate the work process, up to the point where there is no need to be at the machine. Professional machines can be easily integrated into large assembly lines.

There is also no need to use additional components, such as coated rods, fluxes, gases, etc. Hence the high environmental friendliness of resistance welding, which is also important in modern production conditions. Another plus is the ease of welding complex metals. You can weld stainless steel, aluminum and non-ferrous metals. There is no need to use inert gas or non-melting rods.

But, like all types of welding, the contact method has its drawbacks. The most important thing is the high price of professional welding equipment. To equip a small plant with the required number of resistance welding machines, you need to have a considerable budget. Not to mention buying a home welding machine.

In addition, such devices are demanding on the power source. They need to produce a large current, at least 1000 amperes. And for this you need a powerful and stable electrical voltage.

Novice welders will probably consider it a disadvantage that the rules for resistance welding are regulated by a separate GOST and they are quite strict. If at least one point from the rule is not observed, then such a part will simply not be accepted for the next production stage. Simply put, you can't avoid work. We do not consider this a disadvantage, because adherence to welding technology and further quality control is the key to a strong and durable metal structure.

Types of contact welding

There are several types of resistance welding.

These include spot welding (it can be single-point, two-point and multi-point), projection welding, seam welding (can be continuous, stepwise or intermittent), butt welding (performed either by resistance or by fusion).

Combinations of different methods are also possible, for example, seam butt welding or relief spot welding. In this case, the combined method will have all the characteristic features of both types of resistance welding.

Let's take a closer look at the methods of contact electric welding of metal products.

Spot welding

Spot welding is the most common type of resistance welding. Its essence is the formation of so-called points by heating the metal and its further deformation. The points are formed in small increments, forming a welded joint.

Spot welding is quite versatile, it is used to join thin sheet metal, small parts used in electrical appliances, and thick parts up to 2 centimeters. Using this method, fast and high-quality welding of stainless steel is possible.

As for the quality and reliability of the connection, everything is simple: the more points, the more reliable the seam. Beginners mistakenly believe that such a connection is unreliable and can break at any moment. But this is a big misconception. A lot of pressure is used to form the point. It easily deforms the heated metal, which then cools and reliably fixes the parts together.

Relief welding

Resistance relief welding is carried out on the same principle as contact welding, only before work the edges of one part are processed using special tools or machines that form protrusions. The part is placed on top, with the protrusions down. The protrusions can be semicircular or oblong. In the place of the protrusion there will be a point formed by the resistance welding machine. The second part remains unchanged, it is placed below.

The relief welding method is often used in automobile assembly. It is very complicated due to the need to form protrusions and is therefore rarely performed at home.

Seam welding

Seam welding is somewhat different from other types of contact welding. Here the electrodes are roller, with their help the metal is not only rolled, but also welded. In this case, the welded joint looks like spot welding. But the dots overlap each other by a few millimeters, forming a seam more like a connection made by hand using a coated electrode.

Seam welding is used when welding thin metals up to 3 millimeters. Seam welding is also excellent for welding sealed products, such as tanks and cisterns.

Butt welding

Resistance butt welding also uses heat and pressure, but in a different plane. The seam is formed not between the upper and lower electrodes, but in the middle. To better understand the concept, look at the diagram below.

Butt welding is divided into resistance welding and fusion welding. In resistance welding, the parts are first joined, then compressed under slight pressure, and only after that a current is supplied to the weld area, which heats the metal, softening it. The metal then cools and a compound is formed.

In fusion welding, parts are preheated to a plastic state and only then connected using pressure. Heating can be either constant, where heat is supplied throughout the entire welding process, or intermittent, where the part is heated at intervals. Intermittent heating is used to save electricity. It is also useful if the parts are small and thin, in such cases there is no need to use heating constantly.

Attentive craftsmen will ask, where does the molten metal disappear? Indeed, with other welding methods, when melting, the metal begins to oxidize and slag is formed. And this creates additional problems. The fact is that in resistance welding, the current has an electrodynamic effect, so it easily throws the molten metal outside the welding zone.

Making a resistance welding machine

Now that we have dealt with all the features, we can decide whether to use resistance welding in our work. Some people will be put off by the high price of the equipment, but in the table of contents we wrote that many craftsmen make resistance welding machines with their own hands. Its power is quite enough for working at home.

We will tell you how to make such a device yourself. With its help you can perform resistance spot welding. By the way, there are many videos on the Internet with step-by-step instructions. Study them to get the full picture. So, to make contact welding, we do not necessarily need a new, but definitely a working transformer (you can take it out of an old microwave oven; use two transformers if you need a higher power device).

We also need a large diameter copper wire (instead of one thick wire, you can use many thin ones, tying them into a bundle), metal levers (we will use them to clamp the electrodes), a base for the apparatus (this can be a thick sheet of heavy metal or something) it is very stable; you can screw the device directly to the table), clamps, screwdrivers of different sizes, cables, electrical tape (or any other material for winding), copper parts with a pointed end that will act as electrodes.

That's all. Let's start assembling. When assembling a resistance welder, you must understand that the key structural element is the transformer. It’s not for nothing that we recommended that you take it out of the microwave, since it’s an ideal brew for a small homemade device. In order for your device to weld metal 1 millimeter thick, you will need a power of 1 kW. The greater the power, the greater the range of thicknesses.

You don't need the entire transformer to work. But only the primary winding and magnetic circuit. The secondary winding must be removed from the transformer (do this as carefully as possible so as not to damage the remaining elements).

There are also shunts, they also need to be dismantled. Shunts are located on both sides of the secondary winding.

Next you need to make a new winding. To do this, take a stranded wire with a diameter of at least 10 millimeters. Two or three turns will be enough for the transformer to operate correctly.

If the wire's insulation is too thick, you can remove it and wrap the wire with fabric or PVC tape. If you are assembling a powerful device and for this you took two transformers, then there should be one winding for both.

In this case, it is important to correctly connect all the leads from the primary winding of both transformers.

Now you need to put all the components together. You need to install the transformer in the housing (you can make it yourself or take a suitable one from a non-working household appliance), connect the copper electrodes, all the buttons and controls. Basic knowledge of electrical engineering will help you here.

Instead of a conclusion

Resistance welding is a relatively simple, fast and convenient method of joining different metals. With it, welding stainless steel or aluminum, which have a thick layer of oxide film, is not dangerous, and the work can be entrusted to a less experienced craftsman and the quality of the connection will still be good. You can do this kind of welding at home by building a resistance welding machine with your own hands. Share your experience in the comments, it will be useful for beginners. We wish you good luck in your work!

Source: https://svarkaed.ru/svarka/vidy-i-sposoby-svarki/kak-smasterit-kontaktnuyu-svarku-svoimi-rukami.html

How to do resistance welding with your own hands?

[DIY resistance welding] is a very useful skill.

If any inverter model is available for free sale, a person planning to weld at home has a choice - purchase a ready-made device or make it himself.

In this article, we will look at what it is, demonstrate an instructional video on resistance welding, give step-by-step instructions on how to carry out resistance welding yourself, and how you can make a homemade resistance welding machine with your own hands from a microwave and used car batteries.

Resistance welding - technology and process

Owners of private houses, motorists and others need welding work.

At home or in a small workshop, using a welding inverter to connect metal parts is quite possible.

The principle of its operation is that, with the help of an electric current, the metal is heated, melted and solidified, forming a weld.

To fix and prevent shifting, the parts to be welded are compressed using electrodes through which an electric current is supplied.

To work at home, powerful power sources will be required, which affects the overheating of household wiring.

Before carrying out work, you should check the quality of the wiring and, if possible, replace it with a new one.

In resistance spot welding, two workpieces are joined along the surface of adjacent edges.

This technology is suitable for thin sheets, small parts and metal rods up to 5 mm thick.

Three types of surface connections are used: using resistance, intermittent reflow or continuous reflow.

For resistance welding, prepared workpieces or sheets are fixed and heated with welding current until melting.

The method is applicable for the following metals:

• low carbon steel;
• non-ferrous metal;
• connections of copper with brass and steel.

Due to strict temperature requirements and the absence of impurities at the joints, this method is rarely used.

When continuously melting a workpiece, pliers or other part clamps are used, they are connected with the current turned on, after melting the edges of the parts being connected, upsetting is carried out and the current supply is turned off.

IMPORTANT TO KNOW: Selecting and designing a hair dryer for soldering microcircuits

This method is most applicable for pipes with thin walls. It is permissible to connect workpieces of different structures.

The main advantage is the high speed of work, the serious disadvantage is the leakage and waste of metal along the weld.

Intermittent melting occurs with alternating tight and loose contact of the workpieces while the current is on.

The clamping pliers ensure closure of the welding line at the point of contact of the workpieces until they reach a temperature of 900-950 degrees Celsius.

This method is used if the initial power of the device is not enough to ensure continuous reflow.

Thus, resistance welding consists of the following steps:

• Preparing surfaces for joining (cleaning, leveling the contour).
• Aligning edges and fixing workpieces under the welding machine.
• Supply of electric current.
• Warming up and melting of the edges of parts under its action.
• Upsetting and turning off the current.

The resistance welding methods discussed above differ in the fixation of workpieces and the supply of current; in general, the welding process is similar.

For home resistance welding, you can design a homemade machine.

Its main operating components are a welding clamp and a voltage supply unit on capacitors, to the low-voltage winding of which an electrode is connected.

The second wing of the clamp serves as a support or is connected (depending on the mounting of the device) with a larger workpiece.

Instructions for resistance spot welding are presented above.

Microwave welding machine

You can make a device for resistance spot welding yourself using a transformer from a microwave.

When making such a welding device, you need to weigh what will be cheaper - buy an inverter or make it yourself, using a transformer from an unnecessary microwave.

The transformer is the most expensive part of our future homemade device. All other consumables - wires, casing and base on which the mounting will be made - will be available in almost any workshop.

We will need a transformer power of at least 1 kW. Using a welding machine using such a transformer, it is possible to spot weld sheets up to 1 mm.

Doubling the transformer power will allow you to work with sheets up to 1.8 mm thick. The transformer of a modern microwave oven can have a power of up to 3 kW.

If necessary, two or three transformers can be used. This circuit will increase the power of the supplied current.

It is necessary to remove the transformer from the metal casing and get rid of the shunts for limiting the current and the secondary winding.

IMPORTANT TO KNOW: Assembling a DC welding machine with your own hands

The microwave oven uses high voltage, so there are fewer loops on the primary winding of the transformer than on the secondary winding.

Because of this, a potential difference appears. Our task is to change the secondary winding, adapting it for resistance welding purposes.

Thoroughly clean the transformer of any residual secondary wiring and shunts, using a wire brush or long narrow object (such as a screwdriver) if necessary.

Only the primary winding will remain intact; we will make the secondary winding again.

Considering the high voltage, we take multi-core electrical wiring with a cross-section of at least one square.

If a circuit of two or more transformers is used, then the conclusions of all secondary windings from them are combined into one.

When one transformer is used, the housing for it can be adapted from the same microwave oven, reducing the width and length.

For a transformer system, the casing can be made from an iron sheet, providing it with an insulating layer. The secondary winding is formed by 2-4 turns of wire.

However, the thick layer of insulation in which the wire is packed will not allow it to bend along the coil.

Therefore, we remove the wire from the insulation and we can use ordinary flexible electrical tape as an insulating coating.

With two or three loops of wire we will achieve a voltage of 2 W.

To supply current to the welding site, we create a lever mechanism, one lever of which is rigidly fixed to the main surface (for the convenience of resistance welding, the transformer in the casing can be secured to the same surface using clamps).

The second lever will compress the parts when lowered. We insert the switch into the primary winding circuit and install it on the upper lever.

This will allow you to simultaneously compress the part and allow current to flow. In this case, pliers are not used, and the tips themselves are pre-soldered to the wires to prevent oxidation.

When spot welding, we will use copper rods with a thickness greater than the diameter of the wire. During operation, they need to be sharpened and replaced if necessary.

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During operation, the part is clamped using levers between two electrodes and current is started.

Battery welding machine

When welding with an electric welding machine, household electrical networks are subject to significant overload.

Prolonged resistance welding can lead to melting of electrical wiring or failure of household appliances. The welding machine can be powered from an autonomous power supply.

This role can be played by a portable station (a generator running on gasoline or diesel), which is very expensive, or you can make a power source yourself.

You will need several car batteries; used ones are quite acceptable. Ideally, they will be of the same capacity.

Then the current strength will be calculated as 1/10 of the battery capacity. If devices of different power are assembled, then the smallest capacity will be needed for the calculation.

Let's make a circuit of series-connected batteries, fastening the corresponding “pluses” and “cons” using wires and wire cutters or, even better, cigarette wires.

You can also use any pliers. From the free “minus” we bring the wire to the electrode, which we clamp in pliers, and from the free “plus” to the working plate, it is recommended to install a rheostat in the circuit.

The resulting welding machine for spot welding from car batteries is ready and can be used away from a source of electricity.

You can make a homemade charging device for it. This option can be successfully used by experienced welders and is not recommended for gaining welding skills.

As shown in the article, homemade resistance spot welding is quite accessible. We reviewed the options and technology of resistance welding.

The information provided will help you gain initial resistance welding skills and create a welding inverter for spot welding yourself using available tools.

Source: https://rezhemmetall.ru/kontaktnaya-svarka-svoimi-rukami.html

DIY spot welding for batteries

In electrical supermarkets you can purchase a machine for spot welding AA batteries of various designs. Such devices are quite expensive. Do-it-yourself spot welding for batteries significantly saves money. Every radio enthusiast can make such equipment at home.

A spot welder made by an amateur

Working principle of resistance welding

For those who are passionate about making homemade mobile electrical devices, sometimes it is simply necessary to acquire a resistance welding machine. Do-it-yourself spot welding for lithium batteries practically does not heat them up, which preserves the sensitive structure of the products from destruction.

Contact welding of metal elements is carried out on a narrow mini platform with a diameter of about 2 mm. A powerful electrical pulse of electric current in the working area melts the metal and thereby holds the parts together. High-level heating (about 10000C) occurs only at the point of contact and does not spread further.

https://www.youtube.com/watch?v=qOY43JMDQTw

The pulse travel time is no more than 450-500 ml sec. On a homemade installation, the time period is set with a resistor (variable resistance). The welding current can reach 450-1300 amperes. The technical parameters of welding equipment are regulated by a capacitor and a transformer.

Contactors made from copper billets are installed in welding devices. In a home workshop, electrodes can be made from ground tips of unnecessary soldering irons. Non-ferrous metal is an effective conductor of high current. The connecting copper cables are selected to be equal in cross-sectional area to the diameter of the electrode.

Note! The ends of the wires are pressed into copper lugs with mounting holes, and they are connected with copper bolts to the electrodes.

How is resistance welding carried out?

Do-it-yourself spotter from a welding machine

The spot welding of battery terminals occurs as follows:

1. A nickel strip is placed on the terminals of the battery poles.
2. A pair of electrodes is lowered onto the strip at the location of the terminal.
3. Press the start button of the welding machine. A powerful impulse is sent to the work area.
4. As a result, the nickel plate is welded to the battery terminal.
5. While moving the equipment, they continue to weld the next contacts.
6. Welding batteries must be accompanied each time by changing the polarity of the poles of the next battery.

Making welding equipment yourself

Do-it-yourself wiring diagram at the dacha

Before you begin manufacturing the device, you need to decide on its design. The Internet publishes a lot of options on how to make resistance welding for AA batteries. One of the device options is made in this order.

Preparation of equipment and materials

Before starting work, you need to prepare the necessary equipment and materials:

• transformer;
• variable resistance - resistor;
• power cable 2 m long, the cross-sectional area of ​​which is approximately 32 sq. mm;
• copper crimp lugs;
• tray with holes ø 18 mm;
• plexiglass sheet measuring 300 x 300 mm;
• hardware;
• two springs;
• two-core wire;
• contactors in the amount of 2 pcs.;
• two cylinders ø 45 mm x 30 mm turned from copper;
• microswitch;
• Nickel welding strip.

Important! In the article, the dimensions and number of assembly elements are given abstractly. Here we offer only recommendations on how best to make a welding machine.

Instructions for making a welding device

1. Plexiglass is cut with a circular saw or jigsaw into pieces according to the drawing;
2. Holes are made in them, inside which threads are then cut.
3. Connect the parts into a transparent box of the power unit;
4. The secondary winding in the transformer is dismantled;
5. Two turns of power cable are wound onto the primary winding.
6. The free ends of the cable are stripped. They are crimped with tips.
7. The ends of the contactors are sharpened with an abrasive disc until “spots” with an area of ​​about 1 mm2 are obtained.
8. The cores of the network wire are connected to the primary winding of the transformer.
9. A microswitch and a resistor are connected in series to one of the wires.
10. At the other end of the power cord, a plug is attached to connect to a household electrical outlet.
11. The transformer is secured with screws in the device body.
12. The microswitch is fixed on one of the sides of the box.
13. The resistor is also attached.
14. Mounting holes are drilled in the copper cylinders on the side and in the center.
15. Contactor electrodes are threaded into the cylinders.
16. Through the mounting holes, screws are used to secure the tips to the sides of the barrels.
17. A lifting and lowering mechanism is assembled from two plexiglass platforms, springs, and barrels with electrodes, which is fixed on the body of the power unit.
18. The plug is connected to the socket.
19. Lowering the spring-loaded plate with electrodes, press the contact strip to the battery pole.
20. All that remains is to weld the batteries, combining them into a block.

Instructions for using the welding machine

1. The device is placed on a workbench or desktop so that the operator can comfortably control the welding process:
2. Finger batteries are inserted into the platform openings. The sockets are made so that, in addition to the batteries, the contact tape can be freely placed (see video below).
3. The platform is placed under the electrodes.
4. Lower the top bar with copper contactors by hand, pressing the tape to the next terminal.
5. Using the finger of the other hand, press the microswitch button. The nickel strip is spot welded to the battery terminal.
6. The bar is returned to its original position.
7. The platform is moved, introducing the next connection.
8. The welding process is repeated.
9. After the upper terminals are welded, the block is turned over and the tape is folded upward, leading it onto the next terminals.
10. Weld the pole terminals with a nickel strip.
11. All that remains is to weld the connecting terminals to the final welded joints of the block, with the help of which the block is connected to the consumer.

Do-it-yourself gasoline generator

Important! Before starting work, it is necessary to check the welding on unnecessary parts.

If a burnout or lack of penetration is detected by the resistor (dimmer), the correct current strength of the installation is set.

Expert advice

• The power unit box made of plexiglass must be a completely closed enclosure. This will prevent the installation operator from coming into contact with internal parts under high voltage;
• It is better to paint the inside of the welding unit with black enamel. This will give it a beautiful look;
• It is imperative to maintain equal cross-sectional areas of the power cable and copper contactors. Otherwise, violations of the technical parameters of the labor force and the voltage of the device may occur;
• When working with welding, the worker must wear dielectric gloves;
• If you don’t have branded contact tape on hand, you can cut it out of a beer can.

Do-it-yourself spot welding will significantly save financial costs.

We should never forget about safety rules during the assembly and operation of electrical equipment.

Source: https://amperof.ru/elektropribory/tochechnaya-svarka-akkumulyatorov-svoimi-rukami.html

Powerful resistance welding with your own hands

The resistance welding machine is not only easy to operate, but also easy to manufacture. The main thing is that it is not necessary to have the skills of this work. Even a beginner can figure out how to make homemade contact welding with his own hands and using available devices. What is a contact connection?

Types of contact welding:

Design

A resistance spot welding machine made at home can be designed to solve simple problems that arise in everyday life. With its help, it is easy to apply a seam necessary for repairs or manufacturing of products. Resistance spot welding is obtained by heating individual elements with electric current and ensures a reliable connection, and the product being repaired will last for some time.

The device functions directly depending on the dimensions of the material, its thermal conductivity and the power of the equipment.

The operating parameters are as follows:

1. Low voltage from 1 to 10V.
2. The work takes a few seconds.
3. Current strength from 1000 Amperes.
4. Small melting area.
5. The pressure applied to the area of ​​the repaired sample must be strong.

It is not difficult to make a resistance welding machine with your own hands. It is quite simple to make. For these purposes, you can use current converters from an old TV as an autotransformer. Resistance welding from a microwave, as well as welding from an inverter or from a LATR will also work well.

When choosing the most suitable transformer, the windings are wound again, based on the voltage and current parameters. Designation of spot resistance welding in accordance with the requirements of GOST 14098.

A control scheme for a technical device is being developed, or you can use an existing one posted on Internet pages, again based on the specified parameters. The resistance welding machine is manufactured in accordance with the types of intended work. In many cases, resistance welding pliers are used.

The connection must be made correctly to ensure direct contact, including the passage of current of one parameter. Particular attention is paid to the transformer for resistance welding and the electrodes for resistance welding mounted on the pliers.

On units with insufficient attention to this criterion, sparking occurs and the final result is not achieved. A good solution would also be to do seam contact welding with your own hands from an inverter or to make a unit with your own hands from a microwave oven, as well as a microwave oven.

Self-production

Contact butt welding machines must be safe during operation, and you also need to know for what purpose the device will be used. Homemade contact welding is made at home. To do this, it is taken into account that the thickness of the metal should be no more than 1 mm, and the cross-section of the wire electrodes should not be more than 4 mm.

The welding machine operates at 220 V and 50 Hz, with the output voltage ranging from 4 to 7 V. The pulse current is up to 1.5 thousand A. The resistance welding control unit can be made after watching the video.

The electrical circuits in the drawing combine the following designs:

• switch operating in automatic mode;
• circuits for operating control;
• power unit;
• transformer for resistance welding;
• single-phase thyristor for connecting power to the network.

The winding circuit includes a primary one, which has six outputs for turning on and providing current regulation in the secondary. In this case, the first one connects to the network, and 5 regulate the process parameters.

The starter circuit in the MTT4 drawing includes:

1. Thyristor switch.
2. Through two contacts, the load is simultaneously redistributed to the other 2 contacts through a transformer.

The control circuit consists of:

• power supply from a transformer;
• relay for closing contacts when voltage is applied;
• diode bridge performing the function of a rectifier.

Accessories for resistance welding:

1. Current-impervious housing.
2. A transformer on which a wire is wound.
3. Ticks.
4. Electrodes.
5. Electrical circuits.
6. A number of safety devices: gas pressure gauges at the pressure inlet.

Transformer manufacturing

Contact welding, the main structural element of which is a transformer, is done by hand. You can remove transformer equipment from any device; the main thing is to take into account the calculation of the transformer so that the current strength is at least 2.5 A. The old winding should be removed and the rings should be installed on the magnetic core made of thin electrically conductive cardboard. This wire is wrapped in varnished cloth in more than 3 layers.

To make the primary winding, you should use wires insulated with fabric for better impregnation, with a diameter of 1.5 mm. For the secondary, it is better to use a stranded wire 20 mm in diameter in silicon insulation. Calculate the number of turns based on the power of the device. After winding the perchvica, a cotton ribbon is wound, then the secondary is placed on it. Everything is impregnated with varnish.

A manual machine resistance welder must know all the structural elements. Vacancies for this specialty are in demand. Arc welding also has a transformer in its design solution.

Making pliers

The welding machine for resistance welding is equipped with pliers. Manual pliers for contact joining can be:

• remote;
• stationary.

The second option provides good insulation and perfect contact with the electrodes. To do this, you need to make the remote lever long. It is easier to make handles of the appropriate length on an external structure. The insulation of the moving joint must be reliable; as a rule, washers and bushings made of textolite are used for this.

A welder on resistance welding machines must be certified, but only if he works in production. Doing spot welding yourself is not a difficult task, just like arc welding. Anyone can do it at home.

Execution of work

Arc welding is not suitable for welding individual points.

Before performing work, it is necessary to sharpen the electrodes for resistance welding, every welder on resistance welding machines knows this.

Flash butt welding is performed as follows:

1. Parts are installed between the electrodes.
2. Under the action of the pressing force, a frictional force is created between the electrode and the surface.
3. The maximum gap is set before applying voltage. As current flows, contact resistance is created.
4. Voltage is applied and the electrode moves, gripping the joints, forming a seam.

Quality control of seams is carried out according to state standards. The standard is GOST 14098, which quality control workers are guided by and based on laboratory testing.

About the equipment

General mechanical engineering time standards for resistance welding are necessary to complete production tasks within a given period of time. For production needs, equipment is purchased, for example, Tecna resistance welding, which forms joints in the form of points.

PF Contact Welding LLC produces, repairs and retrofits inverter units. The plan of enterprises aimed at producing products in mechanical engineering must be carried out with the availability of modern devices.

Multi-spot resistance welding machines, including their technology based on the principle of welding mesh and rods in a stationary state. Roller welding with these machines combines methods of performing work in both intermittent and continuous steps.

Do-it-yourself resistance spot welding is needed to repair products made of thin metal, polyethylene, including polyethylene pipes, carried out end-to-end.

Source: https://crast.ru/instrumenty/moshhnaja-kontaktnaja-svarka-svoimi-rukami

How to spot weld a battery yourself

Batteries are used in many household appliances and tools. Sometimes, it is necessary to replace one or more elements. They are connected into a block of a certain voltage, and the poles are welded together with a metal strip using spot welding.

The soldering method is not suitable here, since this connection method causes strong heating of the internal part of the battery, which leads to its failure. Therefore, if you need to repair lithium-ion batteries yourself, you need to purchase a spot welding machine (spotter) or make it yourself.

The simplest way

The easiest way is to weld the batteries with the battery itself. To do this you will need:

• any car battery, suitable for a drill or screwdriver;
• two soldering iron tips or a piece of thick single-core copper wire;
• relay 500-1000 A;
• capacitor;
• variable resistor;
• stranded copper wire with a cross section of 30-40 mm2;
• switch.

In the field, to weld a nickel plate to a battery, all you need is a battery, charging wires, a piece of solid wire and electrical tape.

Two electrodes are made from the wire. Their ends are cleaned, leveled and secured with electrical tape. There should be a distance of 2-3 mm between the ends of the wires, the ends are in the same plane.

The other ends of the monolithic wire are hooked using charging cable clamps. The pre-charging cable is connected to the terminals of the working battery. Polarity doesn't matter.

Spot welding is ready. The nickel strip is installed on the lithium battery. The ends of the electrodes, which are energized, are pressed to the tape.

A short circuit will occur and the metal at the point of contact will melt. The electrodes must be removed quickly to avoid burning the nickel plate.

At home

For convenience and to improve the quality of welding at home, additional elements are used.

The stranded power wire is connected to a working battery using clamps, and the other ends are connected to a normally open relay contact and to a soldering iron tip.

The second contact of the relay is connected to the second tip. The result is such a circuit that when the relay contacts are closed, the voltage of the working battery will be present at the ends of the tips (electrodes).

A large capacitor, a resistor and a switch are used to control the relay. The capacitor and resistor are connected in series. One terminal of the capacitor is connected to the battery. The common terminal of the switch is connected to a resistor.

In the initial state, the switch should be in the position where it is shorted to the working battery. The capacitor will charge. The relay control winding is connected with one contact to the terminal of the container connected to the battery, and the second is connected to the free terminal of the switch.

When switching, the voltage from the capacitor is supplied to the control winding. While the capacitance is discharging, the relay is closed, and current can flow through it in the event of a short circuit.

To weld, it is enough to place a nickel connecting tape on the lithium battery cell, two tips on it, press it and press the switch . The relay contacts will close and voltage will appear on the electrodes.

Since they are shorted through the plate, a short circuit current will flow through it, which will cause the metal to melt between the points of contact of the electrodes. The welding has been completed.

Using a resistor, you can adjust the duration of the control pulse. Adjustment can be done experimentally. It is necessary when the voltage of the working battery and the thickness of the material being welded change.

From a transformer

Spot welding for batteries can be done with your own hands from a transformer. It can be used to weld not only batteries, but also any thin metal products.

To weld batteries, a high-power transformer is not required; 300-500 W is sufficient. The main thing is to be able to rewind the secondary winding.

The primary winding should be 220V 50 Hz. As a winding wire for the secondary winding, you need to use an insulated copper wire of large diameter. It takes three to four turns.

The body of the spot welding machine can be made of plexiglass or plywood. Plexiglas is of course preferable. The base of the housing must be of such a size that it can accommodate a transformer with connecting wires, a button and a lever with electrodes .

The lever is mounted on an axis between aluminum corner posts, which in turn are secured to the base of the device with self-tapping screws. The length of the lever is made in such a way that the electrodes attached to it reach the working platform of the base of the device. The diameter of the electrodes should be 3-5 mm. Their ends are sharpened and the ends are leveled.

The secondary winding of the transformer is connected to the electrodes using a stranded copper wire with a cross-section not less than the cross-section of the electrodes. The length of the wires from the secondary winding to the working part should be minimal. It is better to weld the connections to reduce the circuit resistance or connect them through screw terminal blocks.

The operating button is installed on one of the terminals of the secondary winding. Springs are installed on the lever and button. They are needed for their rapid return to their original state.

To set a specific welding pulse duration, instead of a button, you can use a thyristor or a power relay controlled by an RC circuit. The resistor must be variable, and the capacitor must be large enough to allow the pulse duration to be varied in the range from tens to hundreds of milliseconds.

There are a large number of circuit implementations of spot welding for batteries. Much depends on the materials available. Circuits may change to increase the functionality of the device and improve its consumer properties, but the essence remains the same.

Capacitor device

A spot welding machine made from capacitors will require 8 capacitors of 15,000 μF each for a voltage of 25 V. The capacitors must be connected in parallel so that the total capacitance becomes 120,000 μF.

For charging, you can use any 12-24 V voltage source. It is connected via a switch. Electrodes are also connected to the terminals of the capacitor via a copper cable with a cross section of 16-30 mm2.

The electrodes are located parallel to each other at a distance of three millimeters. The ends are ground and leveled. The welding process occurs as follows.

The capacitors are charged, the switch turns off the charging source. The nickel connection plate is installed on the battery. The electrodes are pressed against the plate, closing the leads of the capacitors through it.

While the capacitance is being discharged, the welding process is taking place at the point of contact. To adjust the pulse duration, you can use a thyristor controlled by an RC circuit with specified parameters.

Spot welding for batteries differs from conventional spot welding in its low power and the shape of the working elements. In conventional machines, the part to be welded is located between the electrodes; in welding for batteries, the electrodes are located on one side of the work being welded.

Source: https://svaring.com/welding/apparaty/tochechnaja-svarka-dlja-akkumuljatorov-svoimi-rukami