This type of welding refers to the spot method. It is convenient when you need to weld small parts to each other, or one small one. Capacitor welding is mainly used to work with non-ferrous metals.
As soon as it became possible to carry out precision welding at home, the method began to gain popularity among inexperienced welders. This situation has added relevance to the issue today. What is this process and how to do welding for home use yourself? We will try to examine this question in detail today.
The first difference that catches your eye is the welding speed and its environmental friendliness. A standard capacitor welder operates at high voltage. This allows you to save energy and get a high-quality and even seam. Its main application is in microwelding or, if necessary, welding large sections. This happens according to this principle:
- Capacitors collect the required amount of energy;
- The charge turns into heat, which is used for welding.
As mentioned earlier, this type of welding is environmentally friendly. The devices do not require liquid for cooling due to the absence of heat emissions. This advantage allows you to add time to the life of the capacitor device.
Operating principle of capacitor welding
During the spot welding process, the parts are clamped by two electrodes, which receive a short-term current. Then an arc forms between the electrodes, which heats the metal, melting it. The welding pulse comes into operation within 0.1 sec., it provides a common melt core for both parts of the workpieces being welded. When the impulse is removed, the parts continue to compress under the pressure of the load. The result is a common weld.
There are secondary windings, from which the current flows to the electrodes, and the primary winding receives the pulse that was formed during the capacitor charge. In a capacitor, charge accumulation occurs in the interval between the arrival of a pulse at two electrodes. Particularly good results come when it comes to or copper. There is a limitation on the thickness of the workpieces; it should not exceed 1.5 mm. This may be a minus, but this scheme works great when welding dissimilar materials.
Types of spot welding
There are two main types of do-it-yourself capacitor welding:
- Transformer. At which the capacitor discharges the energy charge onto the winding of the transformer equipment. In this case, the workpieces are located in the welding field, which is connected to the secondary winding.
- Transformerless.
Advantages
Like all other types, self-condenser welding has a number of positive features:
- With stable operation, it is possible to save energy;
- Reliability and practicality. The speed of operation allows spot welding to be possible with air cooling;
- Speed of work;
- The welding current is very dense;
- Accuracy. Taking into account the dose of energy consumed, a reliable seam of compact thickness is formed in the contact field. This method is widely used for fine welding of non-ferrous metals;
- Economical. Power consumption is 20 kVA maximum. This occurs through power take-off due to voltage stabilization in the network.
DIY unit assembly diagram
The primary winding is passed through a diode bridge (rectifier) and then connected to a voltage source. The thyristor sends a signal to the bridge diagonal. The thyristor is controlled by a special button to start. The capacitor is connected to the thyristor, or more precisely to its network, to the diode bridge, then it is connected to the winding (primary). To charge the capacitor, an auxiliary circuit with a diode bridge and a transformer is turned on.
A capacitor is used as a pulse source; its capacity should be 1000-2000 µF. To design the system, a transformer is made from a Sh40 type core, the required size is 7 cm. To make the primary winding, you need a wire with a diameter of 8 mm, which is wound 300 times. The secondary winding involves the use of a copper bus with 10 windings. Almost any capacitors are used for the input, the only requirement is a power of 10 V, a voltage of 15.
When the work requires connecting workpieces up to 0.5 cm, it is worth applying some adjustments to the design diagram. For more convenient signal control, use the MTT4K series trigger; it includes parallel thyristors, diodes and a resistor. An additional relay will allow you to adjust the working time.
This homemade capacitor welding works using the following sequence of actions:
- Press the start button, it will start the temporary relay;
- The transformer is turned on using thyristors, then the relay is turned off;
- A resistor is used to determine the pulse duration.
How does the welding process take place?
After the capacitor welding has been assembled with our own hands, we are ready to begin work. First, you should prepare the parts by cleaning them from rust and other dirt. Before placing the workpieces between the electrodes, they are connected in the position in which they need to be welded. Then the device starts. Now you can squeeze the electrodes and wait 1-2 minutes. The charge that accumulates in the high-capacity capacitor will pass through the welded fasteners and the surface of the material. As a result, it melts. Once these steps have been completed, you can proceed to the next steps and weld the remaining parts of the metal.
Before welding work at home, it is worth preparing materials such as sandpaper, grinder, knife, screwdriver, any clamp or pliers.
Conclusion
Capacitor welding is very widely used both at home and in industrial areas; as we see, it is very convenient and easy to use, plus it has a large number of advantages. With the help of the information provided, you will be able to take your knowledge to a new level and successfully apply spot welding in practice.
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 qualification, 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 of 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. This technology is also suitable 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 technology's applications are varied, but it has been used with particular success 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, and you can easily find the necessary diagram and detailed description on the Internet. A similar device works as follows:
- 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
Anyone who decides to assemble their own welding machine 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.
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 lies in the relative simplicity of the electrical circuit, which you can assemble with your own hands. The model presented in the video is powered by a welding transformer; alternating current is 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 a humid 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'm not even against it, but there are certain rules for use, I speak as a former welder and a 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 basically not fatal, but it’s 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 voltage 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, that’s for sure. 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 a pulse 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 discharging, the capacitors switch into a parallel connection - the capacitance 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. Open button 1, briefly close (or hold) button 2. We weld 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, the thermal effect of the 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. A very interesting topic, if it would be possible to publish a 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 across a Chinese Vita semi-automatic welding machine (from now on I will simply call it PA), in which the power transformer burned out; my friends just 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 2 mm thick enamel copper wire; for complete rewinding we will need 3.1 kg of 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 by the direct current on the burner, you need to install a 160-200 ampere thyristor in the circuit, see how to do this in the video.
Thank you all for your attention -)
There are many technologies for welding 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 constant voltage power source. 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:
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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 consumables such as 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 are 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. There is no need to be afraid to experiment, choosing different modes with a 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. You won’t be able to cook water pipes and fittings; 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.
