home Boilers Do-it-yourself capacitor welding machine. We are bringing to life a budget semi-automatic device Electrolytic capacitors in welding inverters

Do-it-yourself capacitor welding machine. We are bringing to life a budget semi-automatic device Electrolytic capacitors in welding inverters

There are many welding technologies various materials and among them is capacitor welding. The technology has been known since the 30s of the last century and is of a variety. The joining of metals occurs during melting in places of short circuit of electric current due to the applied discharge energy of charged high-capacity capacitors. The process takes 1-3 milliseconds.

The basis of the device is a capacitor or a block of capacitors, which are charged by a power source DC voltage. After reaching the required energy level during the charging process, the capacitor electrodes are connected to the welding points. The current flowing during the discharge between the parts being welded causes the surfaces to heat to such an extent that the metal melts and high-quality metal is formed.

Despite a number of advantages, capacitor welding has a number of limitations that do not allow its use everywhere. Among them:

Accounts

Free Trial

Equipment advantages

high process speed in automated production, up to 600 points per minute

accuracy of parts connection and repeatability of processes on the line

does not transmit infrared and ultraviolet radiation

equipment durability

welding different metals

low heat generation, no need for coolant

lack of such Supplies like electrodes or welding wire

Despite some disadvantages, the method of joining metals is widely used in industry and in everyday life.

Types of capacitor welding machines

There are two types of capacitor welding machines - with a discharge of energy storage devices directly on the surfaces being welded and with a discharge from the secondary winding of a transformer. The first, transformerless method, is more often used in shock-capacitor welding. The second method, transformer, is used to create a high-quality seam.

Impact-capacitor equipment welds parts when one of the electrodes hits the part. During an impact, the surface parts are pressed tightly against each other. A capacitor discharge occurs, forming a microarc that heats the surfaces to the melting point of metals. The parts are firmly connected.

In the transformer welding method, after charging, the capacitor is connected to the primary winding of the step-down transformer. A potential appears on the secondary winding that is several times smaller than the amplitude of the incoming pulse. During the discharge, the parts are welded, the capacitor is charged again and again transfers energy to the primary winding of the transformer. This allows long bursts of up to 5 discharges per second to be produced, which creates strong and precise welds.

Application specifics

Capacitor welding is an economical process, so it is convenient to use at home with a low-power single-phase network. The industry produces household welders with a power of 100-400 watts, which are intended for home use or in small private workshops.

Capacitor welding has gained particular popularity in car body repair shops. Unlike arc welding, capacitor welding does not burn through or deform the thin walls of sheets of body parts. There is no need for additional straightening.

Capacitor welding is also used in radio electronics for welding products that cannot be soldered using conventional fluxes or fail due to overheating.

Capacitor welding machines are used by jewelers to make or repair jewelry.

In industry, point connection is used for:

welding bolts, hooks, nuts, studs and other hardware to surfaces;
connections between different metals, including non-ferrous ones;
welding of watch parts, photo and film equipment;
manufacturing of optical and lighting devices;
electronic equipment assemblies
and etc.

Capacitor welding is used to join microscopic parts that cannot be welded using the arc method.

DIY capacitor apparatus

You can make a capacitor-type welding machine yourself and use it at home. For this you will need

220 volt transformer with a power of 5-20 W with an output voltage of 5V;
four rectifier diodes with a forward current of at least 300 mA (for example, D226b);
thyristor PTL-50, modern replacement T142-80-16, KU 202 or similar;
electrolytic capacitor 1000.0 x25 V;
variable resistor 100 Ohm;
a transformer with a power of at least 1000 W (suitable for microwave ovens);
electrodes or welding gun ( different designs described on the Internet many times);
copper wire with a cross-section of at least 35 mm2. - 1 meter.
switches, fuses, housing at your discretion.

If the installation is carried out according to the diagram without errors and the parts are in good working order, then there will be no problems with the operation of the device.

There is only one problem - the output transformer. If you really decide to use a microwave transformer, and it can be bought cheaply on used parts markets, then be prepared that it will need to be rebuilt.

It is necessary to remove the magnetic shunts and the secondary winding and wind 2-5 turns of the secondary winding with a thick copper wire onto the free space. During the setup process, the number of turns may have to be changed. It is considered optimal that the output voltage should fluctuate between 2-7 volts, but this value also depends on the duration of the welding pulse and the thickness of the materials being welded. Don't be afraid to experiment by choosing different modes variable resistor and changing the number of turns. But don't try to get the machine to do what a conventional arc process can do. Boil water pipes and the fittings will not work, this device is for other purposes.

Devices for the transformerless type are not much more complicated, but they are more cumbersome. You will need a set of capacitors with a total capacity of about 100,000 microfarads. This is a decent weight and size battery. It can be replaced with a compact ionistor, but the device is not cheap. In addition, electrolytic capacitors do not last long. Therefore, portable and household capacitor spot welding machines are usually manufactured using a transformer circuit.

Modern devices are manufactured using slightly different technologies. The frequency and power of the discharge are regulated by PIC controllers; it is possible to automate processes and control via a computer or monitor interface. But the physical processes of welding have not changed. Having once assembled the simplest unit, you can subsequently add elements of computer control, production automation and control to it.

If this topic is close to you and you are ready to complement it or challenge it, share your opinion, tell us, post descriptions of your solutions in the comments block.

The device that we will present in this article is called “capacitor welding”. This welding can be used to connect very small or thin objects and parts. Its difference from standard spot welding is that the heating of the joint of parts is carried out due to the energy of the discharge of capacitors.

Lots of electronic fun stuff in this Chinese store.

The convenience of this type of design is relative simplicity electrical diagram, which you can assemble with your own hands. The model presented in the video is powered by a welding transformer, alternating current converted by a rectifier. The voltage is 70 volts. The current flows through the capacitance, which, if necessary, can be replaced with a conventional resistance of 10 kOhm. After resistance, the current flows to a capacitor bank with a total capacity of 30,000 microfarads. The accumulated charge on the capacitors is released through the thyristor.

After turning on the power, the light comes on, which in this case plays the role of a voltage indicator. When the light stops lighting, it means the capacitor bank is fully charged. After this you are ready to go. The discharge is activated by pressing a button built into the holder. This welding allows you to weld not only thin plates, but also studs of different diameters to metal surfaces. For this purpose, it is possible to hold the pin in the holder.

Discussion

Urnfry yvovlya
+azim meex have you ever touched the terminals of a charged 3.8 uF 250 V capacitor? At the beginning of the video it was said: 30,000 microfarads of voltage is supplied at 70 volts, as a result we get 73.5 joules, this is at least. The range of 10-50 J per impulse already loses its non-lethality and can cause electrical injuries incompatible with life (cardiac fibrillation, death).

Urnfry yvovlya
+azim meex
70 volts is the minimum voltage for the capacitor, since it supplies power from 70. What does the drop have to do with it? Check it out, and then tell me about the path it takes.

Alexey Grachev
+toyama tokanava in damp room with a bunch of metal utensils all around? Moreover, the voltage is probably indicated not as constant, but as variable, right? No, you can kill yourself with 12 volts if you want, but I haven’t met such people. And then, almost all transformer welding works at a voltage of about 70 volts and no special problems arise.

toyama tokanava
I don't even mind, but there is certain rules for use, speaking as a former welder and former electrician. Safety rules to help you.

Vladimir lokot
+aleksey grachev a fully charged capacitor with a hundred times smaller capacity, when discharged through a finger, makes 2 burnt holes in it, quite deep by the way, this is, in principle, not fatal, but damn painful. I don’t even know what to compare it with - it’s much more painful than a wasp sting, for example. But to be honest, I’m afraid to imagine what kind of “holes” this fool will burn.

Alexey Grachev
+vladimir lokot it all depends on the voltage. You can charge a hundred farads at 30 volts and upon contact with your finger it will only pinch, or you can charge one microfarad at a thousand volts and then it won’t seem enough, there will be holes and whatever you want. Ohm's law, damn it.

Vladimir lokot
+ Alexey Grachev there is more than 30 volts, but even 30 volts is enough for a normal breakdown of the skin. And in this case, the charge is essentially important, and it directly depends on the capacity of the capacitor bank.

Alexey Grachev
+vladimir lokot yes, there are 70 volts. I have felt this tension on myself more than once, since I regularly cook with both alternating and direct current, in the latter case through a diode bridge and capacitors. It’s noticeable, of course, but obviously not to the full power of the welder; I’m not an iron man. So Ohm’s law rules and it doesn’t matter to him what the circuit is powered by - a power plant, batteries or capacitors.

Vladimir lokot
+ Alexey Grachev doesn’t want to argue with you, but 70 volts from a welder is garbage compared to the instantaneous discharge of a capacitor battery of good capacity; Even 220V from a power socket is garbage. And Ohm’s law, which you mentioned in vain twice here, perfectly describes why, if you think about it a little. When such a capacitor is instantly discharged, a short-term but very large current is obtained, and this is very, very serious.

Alexey Grachev
+vladimir lokot yes, they discharge quickly, remember the same lightning, but if you close them through a resistance or a voltmeter (which itself is essentially a resistance), the process will slow down depending on the number of ohms indicated on the resistor.

Vladimir lokot
+ Alexey Grachev I don’t want to convince you, but do a simple experiment: charge a capacitor of at least 50-100 uF to 50-100V and touch its legs with your finger. Then tell us how the resistance of the skin affects the discharge rate of the capacitor; no, it will have an effect, of course it will, of course. There are people who twist 220 wires while holding 2 wires and it only tingles. Or which the police stun gun is completely ignored. But these are rather exceptions.

Alexey Grachev
+vladimir lokot several messages above I already wrote about the presence of welding with capacitors. The fact that 70 volts hit you noticeably does not prove anything. Farewell.

Sergey pn
Dangerous. You can hit someone on the head with this crap and it will be bad. Otherwise, there’s nothing dangerous, why talk about something we don’t understand.

Sapar malikov
I constantly repair amplifiers there +/-100 volts DC and capacitors in modern amplifiers are at least 4 pieces of 10,000 uF at 100 volts, sometimes we forget to discharge the capacitors with a strong current, of course, but there won’t be any holes, especially since the constant is not very harmful to life

alexandr developer
50 or 100? The difference seems to be twofold. Of course, it’s different for everyone, but I calmly held on to the terminals of the laboratory power supply when it read 90. I was about 13 then and nothing. (Of course, I don’t recommend repeating this, especially if the power supply is without current protection, or even more so if the power supply is an impulse generator. Or you are standing on a metal floor barefoot). On the topic - I absolutely don’t understand why there is 70c. I think that when discharged, the capacitors switch to parallel connection– the capacity and discharge current increase and the voltage drops. In addition, the charge there is limited and, in theory, these 70 volts that come in should go through a galvanic isolation (transformer) - if you stand with your bare feet on metal and do not apply or apply the second electrode poorly, it may shock you, but certainly not kill you.

Sergey psg
scheme.
https://fotki.Yandex.Ru/next/users/ink740/album/41349/view/852249
https://fotki.Yandex.Ru/next/users/ink740/album/41349/view/852248
scheme. Personally, I would collect it this way.
If you exclude the diode between 1 and 2 and the jumper between 3 and 4, then you can insert a diode bridge. Hint as below picture. Too lazy to draw 2 identical ones.
The nominal values of the parts must be counted. Under specific conditions.
A competent person will figure it out, but a competent person in another area of skills will pay a competent person in electronics and electrical engineering.)
Logic of work.
1. Turned on 220, all switches are open.
2. Closed button 1 and wait for the charging current to stop (the lamp has gone out).
3. Opened button 1, briefly closed (or held) button 2. We welded the part.
4. Opened switch 2.
If I made an inaccuracy somewhere, I think Alexander will correct me.

Sergey psg
+dim russ I haven’t made yet.
The author in the video says the capacitor capacity is 30 thousand microfarads. The voltage on the bridge is 70 volts = on the capacitors 100-110 volts. The capacitors themselves must be taken at a higher voltage of 125-160 volts. 160 is even better. I don't remember the range of voltages for capacitors. Whether it is possible to say more or less can only be answered by practice. Place the container in a larger position, so it is possible that the welded surface will burn out (burning), may the welders forgive me. Put less, there won’t be enough energy for the process. Is it possible to reduce the voltage? Yes you can, but! If my memory serves me correctly, the dependence of the amount of stored energy on the voltage in the capacitors is quadratic. That is, the voltage is 2 times lower = the energy is 4 times lower.
Therefore, first do as the author says: 70 volts on the secondary = 100 volts on the condensers * 30 thousand microfarads. And then if something doesn’t suit you, select the parameters for yourself. Because welding the lead to the battery is one thing, but using it in auto straightening is more powerful.

Evgeniy Fedorov
Helpful information! I do contact welding without any electronics, although the button is via a thyristor on the primary. Timer for small thicknesses. I weld plates with a thickness of 01 to 1.5 mm.

azim meex
+vahe vardanyan, firstly, the powder will blow over the welder’s hands and face, secondly, the graphite will carbonize the welding point (not the seam), which will make it more fragile and thirdly, it will reduce the resistance of the welding site and at the same time thermal effect current

Alexey Polushkin
the energy of a charged capacitor is converted into heat, under the influence of which the metal melts at points with minimal resistance, that is, in places where it is pressed by electrodes. The energy of the capacitor is e=c*u*u/2, which means that by raising the voltage by 2 times, we increase the energy by 4 times. Many capacitors are better than one, because due to the design features, a single capacitor is not capable of delivering a large current during a short circuit, and can quickly become unusable. Therefore, from a bank of parallel capacitors we will get a noticeably higher current than from one if it had the same capacity as the entire battery.

Valery Lysenko
+ Sergey psg if this is easy for you, then draw a diagram. Take a screenshot or post a photo of this leaflet on a social network. And send us the link. Don't let your tongue run wild that it's simple. I'll figure out the diagram.

Petrow60
good health. Very interesting topic, if it would be possible to publish the diagram with parameters. This video deserves like and respect. Thank you. I look forward to the continuation as a subscriber.

Toyama tokanawa
If you add a pulse current transformer at the output with a turns ratio of one to ten, you can get ten times more current at the electrodes. Take the cross-section of the wires of the windings according to the current in them, the number of turns does not even need to be large, so take it, ten turns and the secondary one turn. I even think it’s possible to weld the reinforcement. I had to repair a welding installation in the fitting shop; they used a mercury rectifier of about 1000 volts and oil capacitors of 100 microfarads, and thyristor control almost similar to yours.

Denis
Dear video author! I do welding similar to yours. I use a capacitor ea-ii-10 with a nominal value of 33000 uF, a voltage of 63 V and a thyristor T-160. I charge the capacitor with a power supply.
From the “+” of the capacitor a wire goes to the anode of the thyristor, and from the cathode of the thyristor it goes to the welding electrode, “-” from the capacitor also goes to the welding electrode. The voltage to the control electrode of the thyristor comes from the “+” capacitor through a micro switch. The thyristor is working, I checked it, and so is the capacitor. For some reason, the thyristor does not open instantly (when the thyristor opens, the voltmeter needle smoothly begins to go to zero) and welding does not occur. Please tell me what could be the problem? Thanks in advance.

Sungazer
+ Denis put on Well, first of all, a thyristor is a powerful, but slow thing.
And secondly, Conder electrolyte is not designed for high currents.
Therefore, during prolonged operation the condenser will overheat. Therefore, it is better to dial the condensers in small denominations and parallel them.

Yury galinsh
+sungazer how to understand “slow thing”? In network power regulators, at a frequency of 50 Hz, the thyristor (semistor) fires 50 (or 100) times per second. Moreover, it “cuts” the sinusoid almost vertically. In this particular case, this is an ordinary switch.
An electrolytic capacitor drops, if I’m not mistaken, 80% of its capacity in milliseconds.
I can assume that the thyristor itself is faulty. And as far as I remember, a current limiter (resistor) was installed at the control electrode. Well, the capacitor can smoothly discharge through the control electrode.

Alexander polyulyakh
You need to look for components on radio markets or order them on the Internet. Everything is. The greater the capacitance of the capacitors, the greater the charge. The microswitch sends micro currents to the thyristor and it instantly releases the entire impulse of the accumulated energy of the capacitors.

User0011
+ look for Anton Tumanov at scrap metal collection points! They don’t use aluminum for scrap; they don’t take thin scrap metal or aluminum foil! Therefore, you can buy at the price of ferrous metal. No need to overpay somewhere in the markets! And if you get the receivers interested (etc.). There is so much of this “barrel”, and so much of this one. You can collect it quickly.

I came into my hands with a Chinese Vita semi-automatic welding machine (from now on I will simply call it PA), in which it burned out. power transformer, just friends asked me to repair it.

They complained that when they were still working, it was impossible for them to cook anything, there were strong splashes, crackling, etc. So I decided to bring it to a conclusion, and at the same time share my experience, maybe it will be useful to someone. Upon first inspection, I realized that the transformer for the PA was wound incorrectly, since the primary and secondary windings were wound separately; the photo shows that only the secondary remained, and the primary was wound next to it (that’s how the transformer was brought to me).

This means that such a transformer has a steeply falling current-voltage characteristic (volt-ampere characteristic) and is suitable for arc welding, but not for PA. For Pa, you need a transformer with a rigid current-voltage characteristic, and for this, the secondary winding of the transformer must be wound on top of the primary winding.

In order to start rewinding the transformer, you need to carefully unwind the secondary winding without damaging the insulation, and cut off the partition separating the two windings.

For the primary winding I will use copper enamel wire 2 mm thick; for complete rewinding we will need 3.1 kg copper wire, or 115 meters. We wind turn to turn from one side to the other and back. We need to wind 234 turns - that's 7 layers, after winding we make a tap.

We insulate the primary winding and taps with fabric tape. Next we wind the secondary winding with the same wire that we wound earlier. We wind tightly 36 turns, with a shank of 20 mm2, approximately 17 meters.

The transformer is ready, now let's work on the choke. The throttle is an equally important part in the PA, without which it will not work normally. It was made incorrectly because there is no gap between the two parts of the magnetic circuit. I will wind the choke on iron from the TS-270 transformer. We disassemble the transformer and take only the magnetic circuit from it. We wind a wire of the same cross-section as on the secondary winding of the transformer on one bend of the magnetic circuit, or on two, connecting the ends in series, as you like. The most important thing in the inductor is the non-magnetic gap, which should be between the two halves of the magnetic circuit; this is achieved by PCB inserts. The thickness of the gasket ranges from 1.5 to 2 mm, and is determined experimentally for each case separately.

For a more stable arc burning, capacitors with a capacity of 20,000 to 40,000 μF must be placed in the circuit and the capacitor voltage should be from 50 volts. Schematically it all looks like this.

In order for your PA to work normally, it will be enough to do the above steps.
And for those who are annoyed D.C. On the burner you need to put a 160-200 ampere thyristor in the circuit, see how to do this in the video.

Thank you all for your attention -)

Developed in the 30s of the twentieth century, capacitor welding technology has become widespread. A number of factors contributed to this.

Simplicity of the design of the welding machine. If desired, you can assemble it yourself.
Relatively low energy intensity of the working process and low loads created on the electrical network.
High productivity, which is certainly important when producing serial products.
Reduced thermal influence on the materials being joined. This feature of the technology allows it to be used when welding small-sized parts, as well as on surfaces where the use of conventional methods would inevitably lead to unwanted deformations of the material.

If we add to this that to apply high-quality connecting seams it is enough to have an average level of qualifications, the reasons for the popularity of this method of contact welding become obvious.

The technology is based on conventional contact welding. The difference is that the current is not supplied to the welding electrode continuously, but in the form of a short and powerful pulse. This impulse is obtained by installing high-capacity capacitors in the equipment. As a result, it is possible to achieve good indicators of two important parameters.

Short thermal heating time of the parts being connected. This feature is successfully used by manufacturers electronic components. Transformerless installations are best suited for this.
High current power, which is much more important for the quality of the seam than its voltage. This power is obtained using transformer systems.

Depending on production requirements, one of three technological methods is chosen.

Spot capacitor welding. Using a short pulse of current emitted by a capacitor, parts are connected in precision engineering, vacuum and electronic engineering. Fits this technology and for welding parts that differ significantly in thickness.
Roller welding produces a completely sealed joint consisting of multiple overlapping welding points. This determines the use of technology in the manufacturing process of electric vacuum, membrane and bellows devices.
Butt welding, which can be performed either by contact or non-contact methods. In both cases, melting occurs at the junction of the parts.

Application area

The areas of application of the technology are varied, but with particular success it is used for attaching bushings, studs and other fasteners to sheet metal. Taking into account the characteristics of the process, it can be adapted to the needs of many industries.

Automotive industry, where it is necessary to reliably connect body panels made of sheet steel.
Aircraft manufacturing, which places special demands on the strength of welds.
Shipbuilding, where, given the large volumes of work, saving energy and consumables gives a particularly noticeable result.
Production of precision instruments where significant deformations of the parts being connected are unacceptable.
Construction in which sheet metal structures are widely used.

Equipment that is simple to set up and easy to use is in demand everywhere. With its help, you can organize the production of small-scale products or develop a personal plot.

Homemade capacitor welding

In stores you can easily purchase ready-made equipment. But due to the simplicity of its design, as well as the low cost and availability of materials, many people prefer to assemble capacitor welding machines with their own hands. The desire to save money is understandable, but finding the right scheme on the Internet and detailed description can be done without difficulty. Works similar device in the following way:

The current is directed through the primary winding of the supply transformer and the rectifying diode bridge.
The control signal of a thyristor equipped with a start button is supplied to the bridge diagonal.
A capacitor is built into the thyristor circuit, which serves to accumulate the welding pulse. This capacitor is also connected to the diagonal of the diode bridge and connected to the primary winding of the transformer coil.
When the device is connected, the capacitor accumulates charge, powered from the auxiliary network. When the button is pressed, this charge rushes through the resistor and auxiliary thyristor in the direction of the welding electrode. The auxiliary network is disabled.
To recharge the capacitor, you need to release the button, opening the circuit of the resistor and thyristor and reconnecting the auxiliary network.

The duration of the current pulse is adjusted using a control resistor.

This is only a fundamental description of the operation of the simplest equipment for capacitor welding, the design of which can be modified, depending on the tasks being solved and the required output characteristics.

Need to know

To those who decided to collect their welding machine yourself, you should pay attention to the following points:

The recommended capacitance of the capacitor should be about 1000 - 2000 µF.
For the manufacture of a transformer, the Sh40 variety of cores is best suited. Its optimal thickness is 70 mm.
The parameters of the primary winding are 300 turns of copper wire with a diameter of 8 mm.
The parameters of the secondary winding are 10 turns of a copper busbar with a cross-section of 20 square millimeters.
The PTL-50 thyristor is well suited for control.
The input voltage must be provided by a transformer with a power of at least 10 W and an output voltage of 15 V.

Based on this data, you can assemble a fully functional device for spot welding. And although it will not be as perfect and convenient as factory-made equipment, with its help it will be quite possible to master the basics of the welding profession and even begin to manufacture various parts.

There are several ways to seamlessly join metal elements, but among all of them, capacitor welding occupies a special place. The technology has become popular since about the 30s of the last century. Docking is carried out by supplying electric current to to the right place. A short circuit is created, which allows the metal to melt.

Advantages and disadvantages of technology

The most interesting thing is that capacitor welding can be used not only in industrial conditions, but also in everyday life. It involves the use of a small-sized device that has a constant voltage charge. Such a device can easily move around the work area.

Among the advantages of the technology, it should be noted:

high work productivity;
durability of the equipment used;
the ability to connect various metals;
low level of heat generation;
lack of additional consumables;
accuracy of connection of elements.

However, there are situations when it is impossible to use capacitor welding to connect parts. This is primarily due to the short duration of the power of the process itself and the limitation on the cross-section of combined elements. In addition, pulsed load can create various interferences in the network.

Features and specifics of application

The process of joining workpieces itself involves contact welding, for which a certain amount of energy is consumed in special capacitors. Its release occurs almost instantly (within 1 - 3 ms), due to which the thermal impact zone is reduced.

It is quite convenient to carry out capacitor welding with your own hands, since the process is economical. The device used can be connected to a regular electrical network. There are special high-power devices for industrial use.

The technology has gained particular popularity in workshops designed to repair vehicle bodies. During the work they are not burned or subjected to deformation. There is no need for additional straightening.

Basic process requirements

In order for capacitor welding to be performed at a high quality level, certain conditions must be adhered to.

The pressure of the contact elements on the workpiece immediately at the moment of the impulse must be sufficient to ensure a reliable connection. The opening of the electrodes should be done with a slight delay, thereby achieving a better crystallization of metal parts.
The surface of the workpieces to be joined must be free of contaminants so that oxide films and rust do not cause too much resistance when electric current is applied directly to the part. The presence of foreign particles significantly reduces the efficiency of the technology.
Copper rods are required as electrodes. The diameter of the point in the contact zone must be at least 2-3 times the thickness of the element being welded.

Technological techniques

There are three options for influencing workpieces:

Condenser spot welding Mainly used for joining parts with different thickness ratios. It is successfully used in the field of electronics and instrument making.
Roller welding is a certain number of spot connections made in the form of a continuous seam. The electrodes resemble rotating coils.
Impact capacitor welding allows you to create elements with a small cross-section. Before the collision of the workpieces, an arc discharge is formed, melting the ends. After the parts come into contact, welding is carried out.

As for the classification according to the equipment used, the technology can be divided according to the presence of a transformer. In its absence, the design of the main device is simplified, and the bulk of the heat is released in the direct contact zone. The main advantage of transformer welding is the ability to provide big amount energy.

Do-it-yourself capacitor spot welding: diagram of a simple device

To connect thin sheets up to 0.5 mm or small parts, you can use a simple design made at home. In it, the impulse is supplied through a transformer. One of the ends of the secondary winding is connected to the array of the main part, and the other to the electrode.

In the manufacture of such a device, a circuit can be used in which the primary winding is connected to the electrical network. One of its ends is output through the diagonal of the converter in the form of a diode bridge. On the other hand, a signal is supplied directly from the thyristor, which is controlled by the start button.

The pulse in this case is generated using a capacitor having a capacity of 1000 - 2000 μF. To manufacture a transformer, a Sh-40 core with a thickness of 70 mm can be used. The primary winding of three hundred turns can be easily made from wire with a cross-section of 0.8 mm marked PEV. A thyristor with the designation KU200 or PTL-50 is suitable for control. The secondary winding with ten turns can be made of a copper busbar.

More powerful capacitor welding: diagram and description of a homemade device

To increase power indicators, the design of the manufactured device will have to be changed. With the right approach, it will be possible to connect wires with a cross-section of up to 5 mm, as well as thin sheets no more than 1 mm thick. To control the signal, a contactless starter marked MTT4K, designed for electricity 80 A.

Typically, the control unit includes thyristors connected in parallel, diodes and a resistor. The response interval is adjusted using a relay located in the main circuit of the input transformer.

The energy is heated in electrolytic capacitors, combined into a single battery using the table. You can see the necessary parameters and the number of elements.

The main transformer winding is made of wire with a cross-section of 1.5 mm, and the secondary winding is made of a copper busbar.

Job homemade apparatus occurs according to the following scheme. When you press the start button, the installed relay is activated, which turns on the transformer using thyristor contacts welding unit. The shutdown occurs immediately after the capacitors are discharged. The pulse effect is adjusted using a variable resistor.

Contact block device

The manufactured device for capacitor welding must have a convenient welding module that provides the ability to fix and freely move the electrodes. The simplest design involves manually holding contact elements. In a more complex version, the lower electrode is fixed in a stationary position.

To do this, it is fixed on a suitable base with a length of 10 to 20 mm and a cross-section of more than 8 mm. Top part the contact is rounded. The second electrode is attached to a platform that can move. In any case, adjustment screws must be installed, with the help of which additional pressure will be applied to create additional pressure.

It is imperative to isolate the base from the moving platform before the contact of the electrodes.

Work order

Before doing capacitor spot welding with your own hands, you need to familiarize yourself with the main steps.

At the initial stage, the elements to be connected are prepared properly. Contaminants in the form of dust particles, rust and other substances are removed from their surface. The presence of foreign inclusions will not allow achieving high-quality joining of the workpieces.
The parts are connected to each other in the required position. They should be located between two electrodes. After squeezing, an impulse is applied to the contact elements by pressing the start button.
When the electrical influence on the workpiece stops, the electrodes can be moved apart. The finished part is removed. If there is a need, then it is installed at a different point. The size of the gap is directly affected by the thickness of the welded element.

Application of ready-made devices

Work can be carried out using special equipment. This kit usually includes:

apparatus for creating an impulse;
device for welding and clamping fasteners;
return cable equipped with two clamps;
collet set;
instructions for use;
wires for connecting to the electrical network.

Final part

The described technology for connecting metal elements allows not only to weld steel products. With its help, you can easily join parts made of non-ferrous metals. However, when executing welding work it is necessary to take into account all the features of the materials used.