We assemble a simple welding machine at home. Do-it-yourself welding machine - is it possible? How to make a mini welding machine with your own hands
With this simple welding machine, you can cut thin metals, weld copper wires, and engrave metal surfaces. Other applications can be easily found. Such a mini welding machine can be powered by 12-24 V.
The welding machine is based on a high-voltage high-frequency converter. Built on the principle of a blocking oscillator with deep transformer feedback. The generator generates short-term electrical impulses that repeat at relatively large intervals. The clock frequency is in the range of 10-100 kHz.
The transformation ratio of this circuit will be 1 to 25. This means that if you apply a voltage of 20 V to the circuit, then the output should be about 500 V. This is not entirely true. Since any impulse transformer source or generator without load has powerful high-voltage impulses, reaching a voltage of 30,000 V! Therefore, if you disassemble any impulse Chinese charging, you will see a soldered resistor parallel to the output capacitor. This is also a network load, without a resistor, the output capacitor will quickly leak out due to overvoltage, or worse, it will explode.
Therefore, attention! The voltage at the output of the transformer is life-threatening!
Diagram of a mini welding machine
Required details:
- The transformer is homemade, the manufacturing procedure is described below.
- Resistors - 0.5-2 W.
- The transistor was used FP1016 but is hard to find due to its specificity. Can be replaced with a transistor 2SB1587, KT825, KT837, KT835 or KT829 with a change in the polarity of the power supply. Another transistor with a collector current of 7 A or more, a collector-emitter voltage of 150 V or more, with a high gain (composite transistor) is also suitable.
Transformer manufacturing
The transformer is wound on a piece of ferrite rod from a radio receiver.- Collector winding - 20 turns of wire 1 mm.
- Base winding - 5 turns with a reason of 0.5-1 mm.
- High-voltage winding - 500 turns with an occasion of 0.14-0.25 mm.
We collect the scheme. If everything is in order, everything should start without problems. Since the operating frequency of the generator exceeds the audio frequency, you will not hear a squeak during operation, so do not touch the transformer output with your hands.
Start the generator with a voltage of 12 volts and increase if necessary.
The arc is ignited from a distance of 1 cm, which indicates a voltage of 30 kV. The high frequency prevents the burning arc from breaking, as a result of which the arc burns very stably. When using a copper electrode in close contact with another electrode, a plasma medium (copper plasma) is formed, resulting in an increase in the temperature of arc welding-cutting.
Tests of the welding machine by cutting and welding
We cut an arc with a razor blade.
We fuse copper wires up to 1 mm thick.
A thick copper wire was used as the electrode. It is clamped in a wooden match, since dry wood is also a good insulator.
If you like this small welding machine, then you can make it larger and more powerful. But be extremely careful.
Also, to increase power, you can assemble a generator according to a push-pull scheme, and even on field-effect transistors, as here -. In this case, the power will be decent.
Also, do not look at the bright discharges of the arc with the naked eye, use special goggles.
Watch the video of making a welding machine on a blocking generator
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small welding machine
“Mobile” electric welders (repairmen, high-altitude workers, etc.) especially value a tool that combines:
- - power and functionality necessary for work;
- - minimum weight;
- - a design that is convenient for transportation in hands (comfortable handle, shoulder strap, etc.).
In the first place are welding inverters.
The design of the welding inverter
The inverter is the most modern welding machine. The current source in it is a block with an electronic inverter circuit (hence the name). Structurally, it is made in the form of a small lightweight box, which can be easily moved from place to place during operation. There are small-sized structures that can hang on the worker's shoulder and do not interfere with his work.
The principle of operation of the welding inverter
The principle of operation of this welding machine is based on a fourfold change in the parameters of electrical energy in the process of its conversion from a standard mains voltage (power is supplied from the mains: 220 V and 50 Hz) to a welding current of several hundred amperes. You can get acquainted with the principle of operation of the inverter in detail in the article "".
All models of welding inverters are highly functional equipment that greatly facilitate the work of electric welders. Their unique options are especially valuable:
- - "HOT START";
- - "ARC FORCE";
- - ANTI STICK.
Your own welding machine will always come in handy on the farm, albeit infrequently, but it is very necessary, and sometimes it’s just not possible without it. Especially if you are used to making things yourself. Therefore, do-it-yourself micro-welding, made from improvised materials and end-of-life household appliances, is just what we need.
We will not consider the option of buying a factory welding machine, as this will require money, but we will immediately follow the path of making home-made mini welding at home. There are several quite affordable schemes of welding machines for self-production, but the contact or spot welding machine seems to be the simplest and least expensive.
So that there is no doubt right away why we will describe exactly the option as, for this we will clearly determine that for this we will not need theoretical knowledge of the electrical engineering course and virtuoso mastery of locksmith skills. Everything will be simple, clear and accessible.
Training
The main part of all electric welding machines is a power transformer (if you do not consider modern electronic welding equipment, also called inverters). Therefore, first of all, we will need to get it from somewhere, and the most suitable and affordable option for this will be an old broken microwave oven. And the bigger it is, the better for us. More precisely, the more powerful its transformer will be and the stronger our welding.
If you want to find an old microwave oven, it’s not a problem by looking for it either from your closest friends (those who are richer), or by looking at free classifieds boards, where they are often offered for a nominal fee. Of the insides of a microwave oven, we will be interested in only one detail - this is a high-voltage transformer.
Here we will immediately determine, without going into particular technical calculations, that contact welding made from such a transformer from a microwave oven will be able to generate a welding current from 800 to 1000 amperes. This current is quite enough to weld together strips of metal up to 2 mm thick, even from stainless steel, which is a difficult task for simple welding.
Preparation of the welding transformer
The high-voltage microwave transformer is a steel core, recruited from thin steel plates and located inside its two windings of copper wire. We need the winding that looks smaller, it is considered primary and will be wound from a thicker conductor. The other winding (the one that is larger in size) will be secondary and we simply do not need it. Here it is in the first place and must be dismantled from the transformer.
To do this, you need to disassemble the transformer, or rather, its core, which is made of steel plates, tightly compressed and fastened together by two thin welds. Here we need to cut these welds, for which you can use either a hacksaw or a grinder with a thin circle.
Keep in mind! There may be transformers fastened with an outer tin casing and bolts. In this case, simply unscrew the bolted connections and carefully open the casing. Everything, problems with further disassembly should not arise.
Perform this operation of disassembling the transformer very carefully, since we still need the primary winding, therefore, in no case do we bend or scratch it when removing it. But we don’t stand on ceremony with the secondary winding, it can be cut and pulled out with a hammer and a chisel in parts, it will be much easier.
As a result, we have a whole and undamaged primary winding of the transformer and its steel core in the form of two separated parts.
Next, we wind the secondary winding of our future welding transformer. Here we still have to buy a piece of new insulated copper wire with a cross section of 50 mm2 or about 8 mm in diameter. To do this, we take it and wind it around the central E-shaped magnetic circuit of the core, making two full turns. We will need all such copper wire, taking into account the output to the welding contacts of about 50 cm, the only condition is that the winding must be made so that it is the middle of the conductor.
Then we assemble the transformer, while the primary winding should remain in its place, and our new winding made of copper wire should be placed instead of the secondary. We fasten the two parts of the core using a conventional two-component epoxy resin and clamp the entire structure in a bench vise for a day. After the epoxy has dried, the transformer is completely ready for operation. A photo
Construction assembly
Having made test measurements with a simple tester, when connecting the primary winding to a 220 V network, we have a voltage of about 2 V on the secondary winding, but with an electric current of about 800 A (this is not measured, but calculated - here we take our word for it). This current strength is more than enough to make a strong welded joint of two metal plates.
Now we make the body. To do this, you can use any materials at hand, such as wood, plywood, sheets of durable plastic or galvanized sheet. The main thing is to place the transformer itself and the lower contact on a solid foundation, since one of the conditions is a strong contact of the welding electrodes with the surface to be welded, which, in turn, is possible with the application of great efforts.
It remains to make welding contacts and the mechanical part of our welding machine will be completed. One of the contacts will be at the bottom and it will be fixed, so it is better to make its base from a wooden block 30 cm long, so it will be easier to attach it to the base. At the end of the bar, using the manufactured bracket, we fasten the welding electrode, to which we connect one of the wires of the power winding of the transformer.
Welding electrodes for microwelding can be made with your own hands from a copper bar with a cross section of 5 to 10 mm in diameter, making a slight sharpening at the end at the point of contact with the surface to be welded. It is better, of course, to use tungsten rods or special electrodes for resistance welding from an alloy of beryllium bronze with zirconium additives for this.
We make the upper contact in the form of a lever. To do this, you can also use a wooden block or a not very massive metal profile in the form of a pipe of small diameter. The only thing is that on a metal lever, the design of the welding electrode attachment will be more difficult, since it will also need to be isolated. At the base of the moving contact lever, we must provide a spring so that the lever in the normal state is constantly in the upper position. To do this, you can use a steel spring or an elastic rubber band.
In conclusion, we complete the electrical circuit of the mini welder by connecting a wire with a standard plug for a 220 V network to the ends of the primary winding of our power transformer, and it is imperative to provide a 220 V switch. For this, both the old wire from the microwave oven and any switch designed for a voltage of 220 V and a current of 5 A, it is better if it is a push-type microswitch (mic).
Important! Do not forget to isolate all electrical connections and contacts well.
Everything, your own hand-made mini welder for a summer residence or at home is ready and, as it turned out, making it yourself is not so difficult. Now you can safely weld small flat parts from various metals, but for this you will need to practice and gain practical skills.
And also you can watch the video on how to make contact spot welding with your own hands and how you can use it.
A good welding machine greatly facilitates all metal work. It allows you to connect and cut various parts of iron, which differ in their thickness and density of steel.
Modern technologies offer a huge selection of models that differ in power and size. Reliable designs have a fairly high cost. Budget options, as a rule, have a short service life.
Our material provides detailed instructions on how to make a welding machine with your own hands. Before starting the workflow, it is recommended that you familiarize yourself with the type of welding equipment.
Types of welding machine
Devices of this technique differ in several types. Each mechanism has some features that are displayed on the work performed.
Modern welding machines are divided into:
- DC models;
- with alternating current
- three-phase
- invector.
The AC model is considered the simplest mechanism that you can easily make yourself.
A simple welding machine allows you to perform complex work with iron and thin steel. To assemble such a structure, you must have a certain set of materials.
These include:
- winding wire;
- core made of transformer steel. It is necessary for winding the welder.
All these parts can be purchased at specialized stores. Detailed consultation of experts helps to make the right choice.
AC design
Experienced welders call this design a step-down transformer.
How to make a welding machine with your own hands?
The first thing to do is to properly make the main core. For this model, it is recommended to choose the rod type of the part.
For its manufacture, you will need plates made of transformer steel. Their thickness is 0.56 mm. Before proceeding with the assembly of the core, it is necessary to observe its dimensions.
How to correctly calculate the parameters of the part?
Everything is quite simple. The dimensions of the central hole (window) must accommodate the entire winding of the transformer. The photo of the welding machine shows a detailed assembly diagram of the mechanism.
The next step is to assemble the core. To do this, take thin transformer plates, which are interconnected to the required thickness of the part.
Next, we wind a step-down transformer, consisting of turns of thin wire. To do this, make 210 turns of thin wire. On the other hand, a winding of 160 turns is made. The third and fourth primary winding should contain 190 turns. After that, a thick platinum is attached to the surface.
The ends of the wound wire are fixed with a bolt. I mark its surface with the number 1. The following ends of the wire are fixed in a similar way with the application of appropriate markings.
Note!
The finished design should have 4 bolts with a different number of turns.
In the finished structure, the winding ratio will be 60% to 40%. This result ensures the normal operation of the machine and good quality of the welding fixture.
You can control the supply of electrical energy by switching the wires to the required number of windings. During operation, it is not recommended to overheat the welding mechanism.
DC apparatus
These models allow you to perform complex work on thick steel sheets and cast iron. The main advantage of this mechanism lies in the simple assembly, which does not take much time.
The welding invector is a design of the secondary winding with an additional rectifier.
Note!
It will be made of diodes. In turn, they must withstand an electric current of 210 A. For this, elements marked D 160-162 are suitable. Such models are often used to work on an industrial scale.
The main welding invector is made from a printed circuit board. Such a semi-automatic welding machine withstands power surges during long-term operation.
Repair of the welding machine will not be difficult. Here it is enough to replace the damaged area of the mechanism. In the event of a serious breakdown, it is necessary to re-carry out the primary and secondary windings.
DIY welding machine photo
Note!
In the arsenal of a home master there are many tools for all occasions.
The welding machine is an indispensable device for real craftsmen. It can be bought in stores. However, it is much more interesting and cheaper to assemble with your own hands.
Some also have a welding machine, which every craftsman dreams of.
Today it can be purchased in specialized stores. There are many models. Various accessories for the device and consumables are sold. Is it possible to make a welding machine with your own hands? The answer is simple: it is possible and even necessary!
Types of welding machines
All devices for welding work are divided into gas and electric. Gas installations are not entirely suitable for domestic use. They require special treatment, as they are equipped with explosive gas cylinders. Therefore, we should only talk about electrical devices. They are also different:
The welding inventory is economical and ideal for home use.
- Generators. These installations have their own current generator. Differ in very big weight and the bulky sizes. Not suitable for home assembly and use.
- Transformers. Such devices can be powered by 220 or 380 volts. They are very popular, especially semi-automatic.
- Inverters. Very economical fixtures, ideal for the home. Differ in small weight, but rather difficult electronic scheme.
- Rectifiers. Easy to make and use. Even novice welders can make quality seams. Ideal for DIY assembly.
How to start assembling an inverter apparatus?
To assemble the inverter, you need to select a circuit that will provide the necessary operating parameters for the device. It is recommended to use Soviet-made parts. This is especially true for diodes, capacitors, transistors, resistors, chokes, thyristors and finished transformers. The equipment assembled on these parts does not require complex adjustment. All parts are very compactly located on the board. For the manufacture of the device with your own hands, you can select the following options:
- The welding machine must work with electrodes up to 4-5 mm in diameter.
- The value of the operating current is not more than 250 A.
- Power source - household network voltage 220 V.
- Welding current adjustment within 30-220 A.
The welding machine consists of several blocks: a power supply, a rectifier and an inverter.
You can start making an inverter-type welding machine with your own hands by winding the transformer in this order:
To assemble the inventory, you will need a ferrite core.
- You need to take a ferrite core Ш8х8. You can use W7x7.
- Primary winding No. 1 consists of 100 turns wound with wire of the PEV 0.3 brand.
- Secondary winding No. 2 is wound with a wire with a cross section of 1 mm. The number of turns is 15.
- Winding No. 3 - 15 turns of PEV wire 0.2 mm.
- Windings No. 4 and No. 5 consist of 20 turns of wire with a cross section of 0.35 mm.
- To cool the transformer, you can use a 220 V, 0.13 A fan. These parameters correspond to a fan from a Pentium 4 computer.
In order for the transistor switches to work smoothly, they need to be energized after the rectifier and smoothing capacitors. The rectifier unit is assembled according to a simple scheme on the board. All nodes of the welding machine are fixed in the body. Well, if the master’s household has a suitable case from a radio device, then you won’t have to make it from improvised materials.
An LED indicator is placed on the front side of the case, which, with its glow, notifies you that the device is connected to the network. Here you can install an additional switch of any type and a protective fuse. The fuse can be installed on the rear wall, as well as in the case itself. It depends on its design and dimensions. Variable resistance, with which the operating current will be adjusted, is also located on the front side of the case.
If the electrical circuits are assembled correctly, everything is checked with a tester or other device, you can test the device.
Back to indexHow to assemble a transformer device?
The process of assembling a transformer welding apparatus is somewhat different from the previous version. It works on alternating current. For DC welding, a simple attachment is assembled to it. To assemble the device with your own hands, you need to get transformer iron for the core and several tens of meters of a thick copper bus or just a thick wire. You can look for these things at the collection points of non-ferrous and ferrous metal, with friends and acquaintances. It is recommended to make the core U-shaped, but it is also possible to make it round, toroidal. Some craftsmen successfully use the stator of a burned-out electric motor as a core. For a U-shaped core, the assembly order can be as follows:
To perform the primary winding, a winding wire is required.
- Dial the core of transformer iron to its optimal cross section of about 55 square centimeters. You can do more, but the device will be heavy. With a cross section of less than 30 cm², the device may lose some of its qualities.
- For the primary winding, a special winding wire with a cross section of 5-7 mm² is ideal. It is made of copper, has heat-resistant fiberglass or cotton insulation. This is very important, since during operation the winding can heat up to temperatures above 100 degrees. The cross section of the wire is usually square or rectangular. It is not always possible to find such a wire. You can replace it with an ordinary wire of the same cross section and modify it: remove the insulation, wrap the wire with strips of fiberglass, soak it thoroughly with a special electrical varnish and dry it. The primary winding consists of 200-230 turns.
- For the secondary winding, you can first wind 50-60 turns. You don't need to cut the wire. It is necessary to turn on the primary winding in the network. Find a place on the wires of the secondary winding where the voltage will be equal to 60-65 V. In order to find this point, you have to unwind or wind additional turns. You can wind aluminum wire, increasing the cross section by 1.7 times.
- The simplest transformer is assembled. It remains to place it in a suitable case.
- For the conclusions of the secondary winding, terminals are made of copper. A tube with a diameter of about 10 mm and a length of 3-4 cm is taken. Its end is riveted, and a hole is drilled in it, the diameter of which is 10 mm. At the other end of the tube, you need to insert the end of the wire, cleaned of insulation, and crimp it with light blows of the same hammer. To strengthen the contact of the wire with the tube-terminal, notches can be applied to it with a core. Homemade terminals are screwed to the body with M10 bolts and nuts. It is advisable to select copper parts. It is possible, when winding the secondary winding, to make taps every 5-10 turns of wire. These taps will allow you to change the voltage on the electrode in steps.
- It remains to make an electrode holder. It can be made from a pipe with a diameter of about 18-20 mm. Its total length is about 25 cm. At the ends, 3-4 cm from the end, notches are cut to about half the diameter. The electrode is inserted into the recess and pressed by a spring from a welded piece of steel wire with a diameter of 6 mm. The same wire from which the secondary winding is made is fastened to the other end with a screw and an M8 nut. A rubber tube of a suitable internal diameter is put on the holder. It is recommended to connect the device to the home network using a switch and wires with a cross section of 1.5 mm² or more. The current in the primary winding usually does not exceed 25 A. In the secondary winding, it can be from 60 to 120 A. When working, it is recommended to take a break after 10-15 electrodes with a diameter of 3 mm so that the transformer cools down. With thinner electrodes, this can be omitted. In cutting mode, breaks should be taken more frequently.