Do-it-yourself semiautomatic device - detailed video

Created plan

Any scheme homemade device provides a separate sequence of work:

• At the initial level, it is necessary to provide a preparatory purge of the system. She will perceive the subsequent supply of gas;
• Then you need to start the arc power supply;
• Feed the wire;
• Only after all actions are completed, the inverter will start moving at a given speed.
• On final stage the seam should be protected and the crater filled;

Control board

To create an inverter, a special control board is required. On this device, the components of the device must be mounted:

• Master oscillator, including a galvanic isolation transformer;
• The node by which the relay is controlled;
• Feedback blocks responsible for mains voltage and supply current;
• Thermal protection block;
• Block "antistic";

Enclosure selection

Before assembling the unit, you need to select the case. You can choose a box or box with suitable dimensions. It is recommended to choose plastic or thin sheet material. Transformers are mounted into the housing, which are connected to the secondary and primary reels.

Coil Matching

Primary windings are carried out in parallel. Secondary reels are connected in series. According to a similar scheme, the device is capable of accepting a current of up to 60 A. In this case, the output voltage will be 40 V. These characteristics are perfect for welding small structures at home.

Cooling system

During continuous work homemade inverter can overheat. Therefore, such a device requires a special cooling system. by the most simple method creating cooling is the installation of fans. These devices must be attached to the sides of the case. The fans must be installed opposite the transformer device. Mechanisms are attached so that they can work on the hood.

A do-it-yourself semi-automatic welding machine is necessary in any household. The high-quality operation of such a device is ensured by the electronic component and the use of carbon dioxide as a welding medium. Such a device is indispensable when carrying out repairs and making connections from thin sheet metal when the workpiece is likely to burn through when using conventional arc welding with electrodes.

Do-it-yourself home-made welding semi-automatic device is quite difficult due to the complexity of its design. Before proceeding with the design of a semi-automatic welding machine, it is required to prepare all the necessary elements of equipment. For welding, you will need to prepare the following elements and materials:

• an inverter that will be capable of delivering a working current of up to 150 A;
• feeder;
• burner;
• flexible carbon dioxide supply hose;
• coil of welding wire;
• welding process control unit.

The design of the semi-automatic welding machine

The semi-automatic welding machine works with the use of carbon dioxide, which protects the molten metal from interaction with oxygen and nitrogen in the air.

Under the influence of high temperature, carbon dioxide decomposes into carbon monoxide and oxygen, which oxidizes the welded metal. To prevent the oxidation process in the semi-automatic welding machine, a special welding wire is used, which has a copper-plated surface. The composition of the copper plating of the wire includes silicon and manganese, which prevent the oxidation process. Welding wire feed is carried out by a special feed mechanism, which ensures a uniform advance of the wire to the welding area.

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Feeding mechanism of semiautomatic welding machine

The feed mechanism of the apparatus for semi-automatic welding requires special attention. This device serves to uniformly feed the wire into the melting zone. The material is supplied by means of a flexible hose. Ideally, the material feed rate corresponds to the melting rate.

The material feed rate is one of the most important criteria that ensures the quality of the welded workpieces. When designing this mechanism, it is required to provide for the possibility of controlling the feed rate of the consumable material.

This function is required in order to be able to work with consumables of various diameters. The welding wire is wound on special spools installed in the material feed mechanism.

In order to design a mechanism, you will need two bearings and an electric motor from car wipers. The smaller the engine, the better for the mechanism. When choosing a motor, it is required to check that it rotates in one direction, and does not rotate from side to side with a certain frequency. In addition, you will need to make a roller with a diameter of 25 mm. This structural element is installed over the thread on the motor shaft.

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Feeder design

The design of the mechanism includes two plates on which bearings are fixed, which are pressed against the roller on the motor shaft.

Compression of metal plates and clamping of bearings is carried out using a specially installed spring. The wire is pulled by passing it along the guides and between the roller and bearings.

The mechanism is mounted on the surface of a textolite plate, the thickness of which must be at least 5 mm. Installation is carried out in such a way that the wire exits at the place where the connector for connecting the welding sleeve will be installed.

A mount is mounted on the plate for installing a bobbin, on which the welding wire is wound.

The bobbin mount is a shaft fixed at an angle of 90° to the textolite plate. At the end of the shaft, a thread is cut for screwing the nut.

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Wire feed control device

As a case for the feed mechanism, you can use a case from a computer unit, which is reinforced to make it more rigid with several metal corners. The electronic part of the device is mounted in the housing.

The computer case includes a power supply that can be used to power the drive electric motor, in addition, the power supply contains elements used to create a mechanism for controlling the supply of consumables to the welding area.

The simplest and most reliable way to control the feed rate of consumables is a circuit based on thyristors. The most simple circuit control does not have a smoothing capacitor. The diode bridge can be used in any design that is capable of delivering current in excess of 10 A.

The transformer used to supply voltage to the drive motor of the mechanism must have a power exceeding 100 watts. In the adjustment mechanism circuit, a VTV16 thyristor is used, which has a flat case, or a thyristor marked KU202, which can have different letters in its marking, they do not affect technical qualities element used in the operation of the control scheme for the supply of consumables to the welding area.

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Subtleties of creating a transformer unit and setting up an inverter

For the operation of the inverter type welding machine, a toroidal type transformer is best suited. The fact is that the efficiency of a toroidal type transformer is much higher, and the degree of dissipation magnetic field minimum.

It is worth noting that this type of transformer has one drawback - the complexity of winding. The primary winding is made with copper wire. The secondary sheath is wound using an aluminum rail with dimensions of 16x2 mm. Before winding primary and secondary, it is required to calculate required amount wire. When installing a transformer, it is necessary to provide a place for installing a fan to blow it, since during the operation of this component of the welding machine under load, a large amount of heat is generated that requires removal from the area where the device component is located in order to avoid overheating and burnout.

For input and output rectifiers, for power switches soldered to copper substrates of the power unit, it is necessary to provide high-quality cooling. This is achieved by setting good radiators. A temperature sensor is located in the body of the most heated radiator. After carrying out all assembly work, the power unit is connected to the control unit. By connecting the power unit to the control unit, the device is connected to the network.

After starting the device, an oscilloscope is connected to it. With the help of an oscilloscope, bipolar pulses are found, the frequency of which is 40-50 kHz. The time between pulses is corrected by changing the input voltage. The time between pulses should be 15 µs.

The pulses on the oscilloscope screen should have rectangular fronts, the duration of which is 500 ns. The indicator of the welding machine, after turning it on to the network, should show a current of 120 A. If this indicator is not reached, it is necessary to eliminate the cause of the low voltage in welding wires. This is often the case if the input voltage is less than 100 V. When the required parameters are reached, it is required to test the device by changing the current while constantly monitoring the voltage. After testing, the temperature is checked.

After the first stage of testing, the inverter-type welding machine is tested in a loaded state. For this purpose, a 0.5 ohm rheostat is used as a load, which must withstand a current of 60 A.

Technical data of our welding machine - semi-automatic:
Supply voltage: 220 V
Power consumption: no more than 3 kVA
Operating mode: intermittent
Operating voltage regulation: stepwise from 19 V to 26 V
Welding wire feed speed: 0-7 m/min
Wire diameter: 0.8mm
Welding current: PV 40% - 160 A, PV 100% - 80 A
Welding current regulation limit: 30 A - 160 A

In total, six such devices have been made since 2003. The device, shown below in the photo, has been working since 2003 in a car service and has never been repaired.

Appearance

Standard welding wire is used
5kg spool of wire with a diameter of 0.8mm

Welding torch 180 A with Euro plug
was purchased at a welding equipment store.

Scheme and details

Due to the fact that the semi-automatic circuit was analyzed from such devices as PDG-125, PDG-160, PDG-201 and MIG-180, the circuit diagram differs from the circuit board, since the circuit loomed on the fly during the assembly process. Therefore, it is better to stick to the wiring diagram. On the printed circuit board, all points and parts are marked (open in Sprint and hover over the mouse).

Signet, see the drawing in the archive

As a power and protection switch, a single-phase automatic machine of the AE type for 16A is used. SA1 - welding mode switch type PKU-3-12-2037 for 5 positions.

Resistors R3, R4 - PEV-25, but you can not install them (I don’t have them). They are intended for fast discharge throttle capacitors.

Now for the capacitor C7. Paired with a choke, it provides stabilization of combustion and maintenance of the arc. Its minimum capacity should be at least 20,000 microfarads, the optimal one is 30,000 microfarads. Several types of capacitors with smaller dimensions and greater capacity were tried, for example, CapXon, Misuda, but they did not show themselves reliably, burned out.

As a result, Soviet capacitors were used, which work to this day, K50-18 for 10,000 microfarads x 50V, in the amount of three pieces in parallel.

Power thyristors for 200A are taken with a good margin. You can put it on 160 A, but they will work at the limit, you will need to use good radiators and fans. The used B200s stand on a small aluminum plate.

Relay K1 type RP21 for 24V, variable resistor R10 wire type PPB.

Pressing the SB1 button on the burner energizes the control circuit. Relay K1 is activated, thereby voltage is applied to the K1-1 contacts solenoid valve EM1 for acid supply, and K1-2 - for the power circuit of the wire pulling motor, and K1-3 - for opening power thyristors.

The SA1 switch sets the operating voltage in the range from 19 to 26 Volts (taking into account the addition of 3 turns per shoulder up to 30 Volts). Resistor R10 regulates the feed of the welding wire, changes the welding current from 30A to 160A.

When setting up, the resistor R12 is selected in such a way that when R10 is turned to a minimum speed, the engine still continues to rotate, and does not stop.

When the SB1 button on the burner is released, the relay releases, the motor stops and the thyristors close, the solenoid valve still remains open due to the charge of the capacitor C2, supplying acid to the welding zone.

When the thyristors are closed, the arc voltage disappears, but due to the inductor and capacitors C7, the voltage is removed smoothly, preventing the welding wire from sticking in the welding zone.

We wind the transformer

We take the OSM-1 transformer (1kW), disassemble it, put the iron aside, having previously marked it. We make a new coil frame from textolite 2 mm thick (the native frame is too weak). Cheek size 147x106mm. The size of the remaining parts: 2 pcs. 130x70mm and 2 pcs. 87x89mm. In the cheeks we cut out a window measuring 87x51.5 mm.
The coil frame is ready.
We are looking for a winding wire with a diameter of 1.8 mm, preferably in reinforced, fiberglass insulation. I took such a wire from the stator coils of a diesel generator). You can also use a conventional enameled wire such as PETV, PEV, etc.

Fiberglass - in my opinion, the best insulation is obtained

We start winding - primary. The primary contains 164 + 15 + 15 + 15 + 15 turns. Between the layers we make insulation from thin fiberglass. Lay the wire as tightly as possible, otherwise it will not fit, but I usually had no problems with this. I took fiberglass from the remains of the same diesel generator. Everything, the primary is ready.

We continue to wind - the secondary. We take an aluminum tire in glass insulation measuring 2.8 x 4.75 mm, (you can buy it from wrappers). You need about 8m, but it is better to have a small margin. We start winding, laying as tightly as possible, we wind 19 turns, then we make a loop for the M6 ​​bolt, and again 19 turns, We make the beginnings and ends 30 cm each, for further installation.
Here is a small digression, for me personally, for welding large parts at such a voltage, there was not enough current, during operation I rewound the secondary winding, adding 3 turns per shoulder, in total I got 22 + 22.
The winding fits back-to-back, so if you wind it carefully, everything should work out.
If you take enameled wire for the primary, then impregnation with varnish is mandatory, I kept the coil in varnish for 6 hours.

We assemble the transformer, plug it into the socket and measure the no-load current of about 0.5 A, the voltage on the secondary is from 19 to 26 Volts. If so, then the transformer can be put aside, for now we no longer need it.

Instead of OSM-1 for a power transformer, you can take 4 pieces of TS-270, although there are slightly different sizes, and I only made 1 welding machine on it, I don’t remember the data for winding, but it can be calculated.

We will wind the throttle

We take an OSM-0.4 transformer (400W), we take an enamel wire with a diameter of at least 1.5 mm (I have 1.8). We wind 2 layers with insulation between the layers, lay them tightly. Next, we take an aluminum tire 2.8x4.75mm. and we wind 24 turns, we make the free ends of the tire 30 cm each. We collect the core with a gap of 1 mm (lay pieces of textolite).
The inductor can also be wound on iron from a color tube TV such as TS-270. It only has one coil.

We still have one more transformer to power the control circuit (I took it ready). It should give out 24 volts at a current of about 6A.

Hull and mechanics

With trances sorted out, proceed to the body. The drawings do not show flanges of 20 mm. We weld the corners, all the iron is 1.5 mm. The mechanism base is made of stainless steel.

See appendix for detailed housing drawings.

Motor M is used from the VAZ-2101 wiper.
Removed trailer return to the extreme position.

In the reel, to create a braking force, a spring is used, the first one that came to hand. The braking effect is increased by compressing the spring (i.e., tightening the nut).

Hull and mechanics drawings
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Scheme and printed circuit board
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Do-it-yourself welding semiautomatic device with a toroidal transformer

That's what happened. The Chinese semi-automatic device failed, which served me faithfully for a little over 5 years. Well, everything has its time. Now we need a new machine. For a long time I chose from what is on sale, but still I decided to make a homemade one. The fact is that sometimes there is a need to weld thicker metals (all sorts of household appliances), so I would like the device to be powerful, but also to easily weld metals of small thickness, and also not hurt the budget. I decided to build on the design popular on the Internet “from Sanych”. But still make some changes. I did not know then that there would be much more changes than I expected.
The first thing a welder needs is a transformer. At an online auction I bought transformer iron tor - a magnetic circuit with a cross section of 5.5 cm X 10 cm.

Why Thor? Well, first of all, I liked that it was factory made in 1978, and the quality was then at its best. Secondly, the efficiency of the toroidal transformer is much higher, and the magnetic field dissipation is much less.
The only drawback of such a transformer is the inconvenience of winding. I will not delve into the calculation of the power of iron, I am not strong in it, but for those who wish, there is a sea of ​​information on the Internet. Primary, as recommended by Sanych, I did copper wire 1.2, but since I purchased a 10-position switch, the number of turns I got was 180 + 12 + 12 + 12, and so on.

I made the secondary with an aluminum shank 16mm2 - 35 turns. Then, however, I had to wind it up, but winding it up (especially from toroidal iron) is always easier than winding it up.

I bought a diode bridge ready-made, mounted on radiators. Radiators cut in half to save space.

The circuit from Sanych for adjusting the wire feed speed in my assembly did not work stably, in the end I simply replaced it variable resistor 10OM 10W. Perfectly keeps the feed rate and does not overheat.

The purchased contactor for 24 volts did not always work from 15 volts, so I had to wind a transformer with 15 and 24 volt outputs. And instead of a contactor, use a magnetic starter with a starting voltage of 24V.

The Sanych circuit uses a 30,000 microfarad capacitor, I also bought it, but in practice it turned out that it was superfluous. A tightly wound toroidal transformer, plus a diode bridge with four diodes, and it turned out that the inductor was quite enough to smooth the current. The machine cooks gently and without splashing.
Throttle, the only part of the Sanych circuit that has not been changed.

For the manufacture of the feeder, I used an electric motor from Volkswagen wipers. Why exactly from Volkswagen, well, firstly, Bosh, and secondly, they gave it to me cheaply. I advise you to look for everything on Internet auctions such as Hammer or AUKRO. It may take a long time, but sometimes you can get the right thing, well, very inexpensively.

The issue with cooling was solved very simply. A fan was installed in the back wall of the apparatus, which is usually installed in the vents.

Gas valve of the times of the USSR for 12 volts.

For three months of work, the do-it-yourself welding semi-automatic device did not fail and did not overheat. I am not strong in circuit diagrams, here is Sanych's diagram with my changes.

How to make a semi-automatic device from an inverter with your own hands

A good owner must have a semi-automatic welding machine, especially for car owners and private property. With him you can always small works do it yourself. If you need to weld a part of the machine, make a greenhouse or create some kind of metal structure, then such a device will become indispensable assistant in personal business. Here the dilemma arises: buy or make yourself. If there is an inverter available, then it is easier to do it yourself. It will cost much less than buying in a retail network. True, you will need at least basic knowledge of the basics of electronics, the presence necessary tool and desire.

Creating a semiautomatic device from an inverter with your own hands

Converting an inverter into a semi-automatic welding machine for welding thin steel (low-alloy and corrosion-resistant) and aluminum alloys with your own hands is not difficult. It is only necessary to understand well the intricacies of the upcoming work and delve into the nuances of manufacturing. An inverter is a device for stepping down electrical voltage to the required level to power the welding arc.

The essence of the semi-automatic welding process in a protective gas environment is as follows. The electrode wire is fed at a constant speed into the arc burning zone. Shielding gas is supplied to the same area. Most often it is carbon dioxide. This ensures that a high-quality weld is obtained, which is not inferior in strength to the metal being joined, while there are no slags in the joint, since the weld pool is protected from negative impact air components (oxygen and nitrogen) with protective gas.

The kit of such a semi-automatic device should include the following elements:

• current source;
• welding process control unit;
• wire feed mechanism;
• shielding gas sleeve;
• carbon dioxide cylinder;
• torch gun:
• wire spool.

Welding post device

Principle of operation

When connecting the device to network converts alternating current to direct current. This requires a special electronic module, a high-frequency transformer and rectifiers.

For high-quality welding work, it is necessary that the future device has such parameters as voltage, current and welding wire feed speed in a certain balance. This is facilitated by the use of an arc power source having a rigid volt-ampere characteristic. The length of the arc is determined by a fixed voltage. The wire feed speed controls the welding current. This must be remembered in order to achieve from the device best results welding.

Easiest to use circuit diagram from Sanych, who has long made such a semi-automatic device from an inverter and successfully uses it. It can be found on the Internet. Many home craftsmen not only made a semi-automatic welding machine with their own hands according to this scheme, but also improved it. Here is the original source:

Scheme of a semi-automatic welding machine from Sanych

Semiautomatic Sanych

For the manufacture of the transformer, Sanych used 4 cores from the TS-720. The primary winding was wound with copper wire Ø 1.2 mm (number of turns 180 + 25 + 25 + 25 + 25), for the secondary winding I used an 8 mm 2 bus (number of turns 35 + 35). The rectifier was assembled according to a full-wave circuit. For the switch, I chose a paired biscuit. I installed the diodes on the radiator so that they do not overheat during operation. The capacitor was placed in a device with a capacity of 30,000 microfarads. The filter inductor was made on the core from the TC-180. The power part is put into operation with the help of the TKD511-DOD contactor. The power transformer is installed TS-40, rewound to 15V. The roller of the broaching mechanism in this semi-automatic device has a diameter of 26 mm. It has a guide groove 1 mm deep and 0.5 mm wide. The regulator circuit operates on a voltage of 6V. It is sufficient to provide optimum feed welding wire

How other craftsmen improved it, you can read messages on various forums devoted to this issue and delve into the nuances of manufacturing.

Inverter setting

To provide quality work semiautomatic device with small dimensions, it is best to use toroidal type transformers. They have the highest efficiency.

The transformer for the operation of the inverter is prepared as follows: it must be wrapped with a copper strip (40 mm wide, 30 mm thick), protected by thermal paper, of the required length. The secondary winding is made of 3 layers of sheet metal, isolated from each other. To do this, you can use fluoroplastic tape. The ends of the secondary winding at the output must be soldered. In order for such a transformer to work smoothly and at the same time not overheat, it is necessary to install a fan.

Transformer winding diagram

Work on setting up the inverter begins with a de-energization of the power unit. Rectifiers (input and output) and power switches must have heatsinks for cooling. Where the radiator is located, which heats up the most during operation, it is necessary to provide a temperature sensor (its readings during operation should not exceed 75 0 С). After these changes, the power section is connected to the control unit. When included in the email the network indicator should light up. Using an oscilloscope, you need to check the pulses. They must be rectangular.

Their repetition rate should be in the range of 40 ÷ 50 kHz, and they should have a time interval of 1.5 µs (the time is corrected by changing the input voltage). The indicator should show at least 120A. It will not be superfluous to check the device under load. This is done by including a 0.5 ohm load rheostat in the welding leads. It must withstand a current of 60A. This is checked with a voltmeter.

A properly assembled inverter during welding makes it possible to regulate the current in wide range: from 20 to 160A, and the choice of working current depends on the metal to be welded.

For making an inverter with my own hands you can take a computer unit, which must be in working order. The body needs to be reinforced by adding stiffeners. An electronic part is mounted in it, made according to the Sanych scheme.

Wire feed

Most often, in such home-made semi-automatic devices, it is possible to feed a welding wire Ø 0.8; 1.0; 1.2 and 1.6 mm. The feed rate must be adjustable. The feeder together with the welding torch can be purchased from the distribution network. If desired and the availability of the necessary details, it is quite possible to do it yourself. Savvy innovators for this use an electric motor from car wipers, 2 bearings, 2 plates and a Ø 25 mm roller. The roller is mounted on the motor shaft. Bearings are fixed on the plates. They stick to the roller. Compression is carried out using a spring. The wire, passing along special guides between the bearings and the roller, is pulled.

All components of the mechanism are installed on a plate with a thickness of at least 8-10 mm, made of textolite, while the wire should come out at the place where the connector connecting to the welding sleeve is installed. A coil with the necessary Ø and brand of wire is also installed here.

Broaching mechanism assy

A homemade burner can also be made with your own hands, using the figure below, where its components are shown clearly in disassembled form. Its purpose is to close the circuit, to provide the supply of shielding gas and welding wire.

Homemade burner device

However, those who want to make a semi-automatic device faster can buy a ready-made gun in the distribution network, along with sleeves for supplying shielding gas and welding wire.

To supply shielding gas to the welding arc, it is best to purchase a standard type cylinder. If you use carbon dioxide as a protective gas, you can use a fire extinguisher cylinder by removing the mouthpiece from it. It must be remembered that it requires a special adapter, which is needed to install the reducer, since the thread on the cylinder does not match the thread on the fire extinguisher neck.

Semiautomatic do-it-yourself. Video

You can learn about the layout, assembly, testing of a home-made semiautomatic device from this video.

Do-it-yourself inverter welding semiautomatic device has undoubted advantages:

• cheaper than store counterparts;
• compact dimensions;
• the ability to cook thin metal even in hard-to-reach places;
• will become the pride of the person who created it with his own hands.

Work on a semi-automatic homemade welding machine: manufacturing technology

Those craftsmen who are fond of welding have repeatedly thought about how to build an installation for pairing elements and parts. The self-made semi-automatic welding machine described below will have the following specifications: mains voltage equal to 220 V; power consumption level not exceeding 3 kVA; works in intermittent mode; correctable
operating voltage is stepped and varies between 19-26 V. The welding wire is fed at a speed ranging from 0 to 7 m/min, while its diameter is 0.8 mm. Welding current level: 40% duty cycle - 160 A, 100% duty cycle - 80 A.
Practice shows that such a semi-automatic welding machine is able to demonstrate excellent performance and a long lifespan.

Semi-automatic device for welding.

Preparation of elements before starting work

As a welding wire, you should use the usual one, the one that has a diameter within 0.8 mm, it is sold in a coil of 5 kg. Such a semi-automatic welding machine cannot be manufactured without a 180 A welding torch, which has a Euro connector. You can buy it in the department specializing in the sale of welding equipment. On fig. 1 you can see a diagram of a semi-automatic welding machine. For installation, you will need a power and protection switch, you can use a single-phase AE (16A) circuit breaker for it. When the device is operating, it will be necessary to switch between modes, for this you can use PKU-3-12-2037.

Scheme of power supply of a semi-automatic welding machine.

Resistors can be omitted. Their purpose is to quickly discharge the inductor capacitors.
As for the capacitor C7, in tandem with a choke, it is able to stabilize combustion and maintain an arc. Its smallest capacitance can be 20,000 microfarads, while the most suitable level is 30,000 microfarads. If you try to introduce other types of capacitors that are not so impressive in size and have a larger capacity, then they will not be reliable enough, as they will burn out pretty soon. For the manufacture of a semi-automatic welding machine, it is preferable to use old-type capacitors; you need to arrange them in the amount of 3 pieces in parallel.
Power thyristors for 200 A have a sufficient margin, it is permissible to install at 160 A, however, they will function at the limit, in the latter case it will be necessary to use fairly powerful fans during operation. The B200s used should be mounted on the surface of an oversized aluminum base.

winding transformer

When making a semi-automatic welding machine with your own hands, the process must begin with the winding of the OSM-1 transformer (1 kW).

Scheme homemade device for winding transformers.

It will initially have to be completely dismantled, the iron should be put aside for a while. It is necessary to make a coil frame, using a textolite with a thickness of 2 mm for this, such a need arises for the reason that its frame does not have an adequate margin of safety. The dimensions of the cheek should be equal to 147x106 mm. In the cheeks, you need to prepare a window, the dimensions of which are 87x51.5 mm. On this we can assume that the frame is completely ready.
Now you need to find a winding wire Ø1.8 mm, it is preferable to use one that has reinforced fiberglass protection.

When making a semi-automatic welding machine with your own hands, you need to create the following number of turns on the primary winding: 164 + 15 + 15 + 15 + 15. In the gap between the layers, you need to lay insulation using thin fiberglass. The wire must be wound with maximum density, otherwise it may not fit.

Scheme of winding a welding transformer.

To prepare the secondary winding, you need to use an aluminum bus, which has glass insulation with dimensions equal to 2.8x4.75 mm, you can purchase it from the winders. It will take about 8 m, but you need to purchase material with some margin. Winding should begin with the formation of 19 turns, after which it is necessary to provide a loop directed under the M6 ​​bolt, then another 19 turns must be made. The ends should be 30 cm long, which will be needed for further work.
In the manufacture of a semi-automatic welding machine, it should be taken into account that if you may not have enough current at a similar voltage to work with dimensional elements, then at the installation stage or already in the process of further use of the device, you can redo the secondary winding, adding it with three more turns per shoulder, in the end result this will give you 22+22.

A semi-automatic welding machine must have a winding that fits back to back, for this reason it should be wound very carefully, this will allow everything to be positioned correctly.
When used to form the primary winding of the enameled wire, then it is mandatory to process it with varnish, the minimum time the coil is held in it is limited to 6 hours.

Scheme of primary and secondary windings.

Now you can mount the transformer and connect it to the mains, which will allow you to determine the no-load current, which should be approximately 0.5 A, the voltage level on the secondary winding should be equivalent to 19-26 V. If the conditions match, you can temporarily postpone the transformer and proceed to the next step.

When making a semi-automatic welding machine with your own hands, instead of OSM-1 for a power transformer, it is permissible to use 4 units of TS-270, however, they have slightly different dimensions, if necessary, for this case, you can independently calculate the data for winding.

Choke winding

Making a case from an old power supply.

To carry out the winding of the inductor, a 400 W transformer should be used, enameled wire Ø1.5 mm or more. The winding must be done in 2 layers, laying the insulation between the layers, while observing the requirement that the wire be laid as tightly as possible. Now you have to use an aluminum tire with dimensions of 2.8x4.75 mm, when winding you need to make 24 turns, the rest of the tire should be 30 cm.
At self-manufacturing It is permissible to wind the throttle on a semi-automatic welding machine on iron borrowed from an old tube TV.
To power the circuit, you can use a ready-made transformer. Its output should be 24 V at 6 A.

Case assembly

At the next stage, you can start assembling the installation case. To do this, you can use iron, the thickness of which is 1.5 mm, the corners will have to be connected by welding. It is recommended to use stainless steel as the base of the mechanism.

The model that is used in the windshield wiper of a VAZ-2101 car can act as a motor. It is necessary to get rid of the limit switch, which works to return to the extreme position.
In the reel, a spring is used to obtain the braking force, you can use absolutely any that is available for this. The braking effect will be more impressive if the effect of a compressed spring begins to influence this, for this you have to tighten the nut.

In order to make a semiautomatic device with your own hands, you need to prepare the following materials and tools:

• enamel wire;
• wire;
• single-phase machine;
• transformer;
• welding torch;
• iron;
• textolite.

The manufacture of such an installation will be a feasible task for the master, who has familiarized himself with the recommendations presented above in advance. This machine will turn out to be much more profitable in terms of cost compared to the model that was produced in the factory, and its quality will not be lower.

Do-it-yourself semi-automatic welding inverter: diagram, photo, video

A semi-automatic welding machine is a functional device that can be purchased ready-made or made from an inverter with your own hands. It should be noted that the manufacture of a semi-automatic device from an inverter device is not an easy task, but if desired, it can be solved. Those who set themselves such a goal should study the principle of operation of a semiautomatic device well, watch thematic photos and videos, and prepare everything necessary equipment and accessories.

Scheme of semi-automatic welding in shielding gas

What is required to convert the inverter into a semi-automatic

To remake the inverter, making it a functional semi-automatic welding machine, you must find the following equipment and additional components:

• inverter machine capable of generating a welding current of 150 A;
• a mechanism that will be responsible for feeding the welding wire;
• the main working element is a burner;
• a hose through which the welding wire will be fed;
• hose for supplying shielding gas to the welding area;
• a coil with welding wire (such a coil will need to be subjected to some alterations);
• an electronic unit that controls the operation of your homemade semi-automatic device.

Electric circuit of a homemade semiautomatic device

Special attention should be devoted to the alteration of the feeder, due to which the welding wire is fed into the welding zone, moving along flexible hose. In order for the weld to be of high quality, reliable and accurate, the speed of wire feed through the flexible hose must match the speed of its melting.

Since wire of different materials and different diameters can be used when welding using a semi-automatic device, its feed rate must be regulated. It is this function - the regulation of the welding wire feed speed - that the feed mechanism of the semiautomatic device should perform.

Appearance of a homemade semi-automatic welder

Internal layout Wire spool Wire feeder (view 1)
Wire feeder (view 2) Attaching the welding sleeve to the feeder Construction of a homemade torch

The most common wire diameters used in semi-automatic welding are 0.8; 1; 1.2 and 1.6 mm. Before welding, the wire is wound on special coils, which are prefixes of semi-automatic devices, fixed on them with the help of simple structural elements. During the welding process, the wire is fed automatically, which significantly reduces the time spent on such technological operation simplifies it and makes it more efficient.

The main element of the electronic circuit of the semi-automatic control unit is a microcontroller, which is responsible for regulating and stabilizing the welding current. It is from this element of the electronic circuit of the semi-automatic welding machine that the operating current parameters and the possibility of their regulation depend.

How to remake an inverter transformer

In order for the inverter to be used for a homemade semiautomatic device, its transformer must be subjected to some alterations. It is not difficult to do such an alteration with your own hands, you just need to follow certain rules.

To bring the characteristics of the inverter transformer in line with those required for a semiautomatic device, it should be wrapped with a copper strip, on which a thermal paper winding is applied. It must be borne in mind that for these purposes it is impossible to use an ordinary thick wire, which will be very hot.

Converted inverter transformer

The secondary winding of the inverter transformer also needs to be redone. To do this, do the following: wind a winding consisting of three layers of tin, each of which must be insulated with a fluoroplastic tape; solder the ends of the existing winding and do-it-yourself winding to each other, which will increase the conductivity of the currents.

Structural diagram of the inverter. used for its inclusion in the semi-automatic welding machine, must necessarily provide for the presence of a fan, which is necessary for effective cooling of the device.

Setting the inverter used for semi-automatic welding

If you decide to make a semi-automatic welding machine with your own hands, using an inverter for this, you must first de-energize this equipment. To prevent such a device from overheating, its rectifiers (input and output) and power switches should be placed on radiators.

Power diodes on additional heatsinks

In addition, in that part of the inverter housing where the radiator is located, which heats up more, it is best to mount a temperature sensor, which will be responsible for turning off the device if it overheats.

After all the above procedures are completed, you can connect the power part of the device to its control unit and connect it to the electrical network. When the mains indicator lights up, connect an oscilloscope to the outputs of the inverter. Using this device, it is necessary to find electrical impulses with a frequency of 40–50 kHz. The time between the formation of such pulses should be 1.5 μs, which is regulated by changing the voltage value supplied to the input of the device.

Oscillogram of welding voltage and current: on the left on the reverse polarity, on the right - on the straight line

It is also necessary to check that the pulses reflected on the oscilloscope screen have a rectangular shape, and their front is no more than 500 ns. If all checked parameters correspond to the required values, then the inverter can be connected to the electrical network. The current coming from the output of the semiautomatic device must have a strength of at least 120 A. If the current strength is less, this may mean that a voltage is supplied to the equipment wires, the value of which does not exceed 100 V. In the event of such a situation, the following must be done: test the equipment by changing the current (in this case, it is necessary to constantly monitor the voltage on the capacitor). In addition, the temperature inside the device should be constantly monitored.

After the semi-automatic has been tested, it is necessary to check it under load. To make such a check, a rheostat is connected to the welding wires, the resistance of which is at least 0.5 ohms. Such a rheostat must withstand a current of 60 A. The current supplied to the welding torch in this situation is controlled using an ammeter. If the current strength when using a load rheostat does not meet the required parameters, then the resistance value this device selected empirically.

How to use a welding inverter

After starting the semi-automatic machine that you assembled with your own hands, the inverter indicator should show a current value of 120 A. If everything is done correctly, then it will happen. However, the inverter display may show eights. The reason for this is most often insufficient voltage in the welding wires. It is better to immediately find the cause of such a malfunction and promptly eliminate it.

If everything is done correctly, then the indicator will correctly show the strength of the welding current, which is regulated using special buttons. Operating current adjustment interval, which provide welding inverters. is in the range of 20–160 A.

Approximate modes of semi-automatic welding of butt welds

How to control the correct operation of the equipment

In order for the semi-automatic welding machine that you assembled with your own hands to serve you for a long time, it is better to constantly monitor temperature regime inverter operation. To implement such control, it is necessary to press two buttons simultaneously, after which the temperature of the hottest radiator of the inverter will be displayed on the indicator. The normal operating temperature is the one whose value does not exceed 75 degrees Celsius.

If this value is exceeded, then, in addition to the information displayed on the indicator, the inverter will emit an intermittent sound signal, which should be immediately paid attention to. In this case (as well as in case of breakage or short circuit of the thermal sensor) electronic circuit The device will automatically reduce the operating current to 20A, and an audible signal will be emitted until the equipment returns to normal. In addition, a malfunction of DIY equipment may be indicated by an error code (Err) displayed on the inverter indicator.

Setting the welding mode on the Resanta inverter

In what cases is a semi-automatic welding machine used?

Practice shows that it is better to use a semiautomatic device in cases where it is required to obtain accurate and accurate connections of parts made of steels. With the help of such equipment, which, if desired, can be made with your own hands, welded joints of thin metal are made, which is very important when repairing the body of a vehicle.

Learning how to work on such a device is also not difficult: lessons taken from qualified specialists or a training video will help with this.