How to make a semi-automatic machine from a welding inverter. We assemble a DC welding machine with our own hands. For work you will need

You can make a semi-automatic machine from an inverter yourself without much difficulty if you have the appropriate technical knowledge. To make a semi-automatic machine with your own hands, you will need to prepare a certain list of mechanisms, devices, tools and materials that are part of the unit.

The semi-automatic inverter includes an inverter and a welding torch.

Preparation for manufacturing and design features

Home craftsmen have developed various schemes for constructing semi-automatic machines from an inverter.

The most common device scheme involves necessary list tools and materials:

welding inverter, which has the ability to deliver an operating current of about 150 A;
a feeding mechanism that ensures the supply of electrode wire to the welding zone;
burner;
flexible hose;
a working reel with electrode wire, which has changes in the device;
device control unit.

The inverter should be about 150 A.

Particular attention should be paid to the feeding mechanism. By using this structural element, the electrode wire is supplied to the burner through a flexible hose. The ideal wire feed speed corresponds to the wire melting speed. The wire feed speed indicator, which is provided by the feed mechanism, has a significant impact on the work process and the quality of the welding seam using semi-automatic welding machine.

When designing a semi-automatic machine, it is necessary to provide for the possibility of changing the speed of feeding the electrode wire into the welding zone. The ability to change the feed rate of electrode material allows you to work with consumables of various diameters and materials. different materials. Most often, when operating semi-automatic welding machines, wire sizes of 0.8 mm, 1 mm, 1.2 mm and 1.6 mm are used. The wire is wound on special spools installed in the welding device.

If the wire feed is carried out completely in automatic mode, then this significantly reduces the time required for welding workpieces.

The semi-automatic control unit is equipped with a channel for adjusting and stabilizing the operating current. The operating current parameters are controlled by a microcontroller in pulse-width mode. The voltage on the capacitor largely depends on the pulse-width current parameter. The voltage on the latter directly affects the strength of the working welding current.

Selecting a transformer for the inverter and assembling the unit

Before independently designing a semi-automatic machine, you need to decide on the type and power of the welding transformer that you plan to install in the semi-automatic machine. It should be remembered that when using wire for welding process minimum size 0.8 mm operating welding current should be 160 A. The power of the welding transformer to produce such current should be 3 kW. When choosing a transformer, you should pay attention to the fact that a transformer with a toroidal core has less weight compared to other types of devices.

When making a transformer, several subtleties need to be taken into account. The transformer needs to be wrapped with a copper strip with dimensions (40 mm - width and 30 mm - thickness). Before using the copper strip, it is first wrapped with thermal paper. You cannot use ordinary copper wire for winding, as it becomes very hot.

The secondary winding of the transformer is made of three layers of sheet metal. The layers of tin are insulated from each other using fluoroplastic tape. At the output, the ends are soldered together to increase conductivity. In the housing where the transformer is installed, a fan is mounted to provide airflow in order to increase the cooling of system components during operation of the device.

The current in the device can be adjusted in two ways: through the primary and secondary windings. Carrying out adjustment in the first way requires the use of a thyristor adjustment circuit. This method of regulation has certain disadvantages, which are eliminated by including a relay and some switching elements in the circuit.

When applying current regulation to the secondary winding, high ripple occurs, to reduce which a thyristor circuit is used. The use of switching circuits increases the weight of the structure and the cost of installation. For this reason, the use of current control through the primary winding is considered more acceptable.

To smooth out ripples, a smoothing inductor and a capacitor with a capacity of about 50,000 microfarads are built into the secondary winding circuit. This configuration of the device allows you to smooth out voltage ripples when choosing any current control scheme.

As a gearbox for feeding wire, you can use a gearbox from a VAZ windshield wiper.

Setting up a semi-automatic inverter

When assembling a semi-automatic inverter with your own hands, it is necessary to ensure good cooling for the power switches, input and output rectifiers using radiators. A temperature sensor must also be installed in the housing. After installation of the power part of the device, it is connected to the device control unit.

The finished device can be connected to the network. After the indicator lights up, connect an oscilloscope to the device and check for correct operation. Bipolar pulses should have a frequency of 40-50 Hz, and the time between them is adjusted by changing the input voltage. The normal time interval between pulses should be 1.5 µs.

The pulses recorded by the oscilloscope must have rectangular edges with a duration of no more than 500 ns.

After checking the inverter, it is connected to the household electrical network. When connecting the device, the indicator should show 120 A. If this indicator is not reached, you need to check that the device is assembled correctly.

After testing the device at idle, the device is tested under load. For this purpose, it is necessary to include a load in the chain of welding wires in the form of a 0.5 Ohm rheostat, which is capable of withstanding a current of more than 60 A. With this load, the current is monitored using a voltmeter.

After assembling the unit, its functionality is checked. To do this, click on the start button. Immediately after this, carbon dioxide begins to flow, after a few seconds the current is turned on, and the feeding of the electrode wire begins. When the device is turned off, the supply of operating current and electrode wire first stops, and only after a few seconds the electrovalve is closed, providing the supply of carbon dioxide to the welding area. As a valve to ensure the supply of carbon dioxide, you can use the water supply valve to the rear window of a VAZ car.

Rules for using a welding inverter and using the unit

After starting the inverter, the controller sets the current required for operation. If configured correctly, the output of the device is electric current is 120 A. Using the control unit, if necessary, the current strength can be changed in the range from 20 to 160 A. When using the unit, you should control the temperature of its heating. The heating temperature should not exceed 75º C. To control it, a temperature sensor should be installed in the device. If the temperature rises above the set maximum, the device should be turned off and given time to cool down. To improve cooling, the unit is equipped with several fans.

Semi-automatic welding machine, made on the basis of an inverter, is used to carry out the procedure for precision welding of products from various types become. In addition, the device is used for welding thin metal workpieces. The use of semi-automatic devices is common when carrying out automotive repair work body

After making semi-automatic welding from an inverter for the home, this unit becomes an indispensable device used in the household to perform large quantity various welding works.

With a good owner mandatory There should be a semi-automatic welding machine, especially for owners of cars and private property. You can always do small jobs with it yourself. If you need to weld a machine part, make a greenhouse or create some kind of metal structure, then such a device will become an indispensable assistant in private farming. Here a dilemma arises: buy or make it yourself. If you have an inverter, it’s easier to do it yourself. It will cost much less than buying at trading network. True, you will need at least basic knowledge of the basics of electronics, availability the necessary tool and desire.

Making a semi-automatic machine from an inverter with your own hands

Structure

It is not difficult to convert an inverter into a semi-automatic welding machine for welding thin steel (low-alloy and corrosion-resistant) and aluminum alloys with your own hands. You just need to understand the intricacies well upcoming work and delve into the nuances of manufacturing. An inverter is a device used to reduce electrical voltage before required level for powering 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 - carbon dioxide. This guarantees a high-quality weld, 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 influence 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 supply hose;
carbon dioxide cylinder;
torch gun:
spool of wire.

Welding station design

Principle of operation

When connecting the device to an electric network, alternating current is converted into 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 parameters such as voltage, current and welding wire feed speed in a certain balance. This is facilitated by the use of an arc power source that has a rigid current-voltage characteristic. The length of the arc is determined by a rigidly specified voltage. The wire feed speed controls the welding current. This must be remembered in order to obtain from the device best results welding

The easiest way to use circuit diagram from Sanych, who long ago made such a semi-automatic machine 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 using this scheme, but also improved it. Here is the original source:

Diagram of a semi-automatic welding machine from Sanych

Semi-automatic Sanych

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

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

Inverter setup

To ensure high-quality operation of a semiautomatic device with small dimensions, it is best to use toroidal type transformers. They have the highest efficiency.

The transformer for operation of the inverter is prepared as follows: it must be wrapped with a copper strip (40 mm wide, 30 mm thick), protected with thermal paper, of the required length. The secondary winding is made of 3 layers of sheet metal, insulated 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 operate smoothly and not overheat, it is necessary to install a fan.

Transformer winding diagram

Work on setting up the inverter begins with de-energizing the power section. Rectifiers (input and output) and power switches must have radiators 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 C). After these changes, the power section is connected to the control unit. When switched on. The network indicator should light up. You need to check the pulses using an oscilloscope. They should be rectangular.

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

A properly assembled inverter when performing welding work makes it possible to regulate the current in a wide range: from 20 to 160A, and the choice of operating current depends on the metal that needs 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 strengthened by adding stiffeners. An electronic part is mounted in it, made according to Sanych’s scheme.

Wire feeding

Most often, such home-made semi-automatic machines provide the possibility of feeding welding wire Ø 0.8; 1.0; 1.2 and 1.6 mm. Its feeding speed must be adjusted. The feeding mechanism together with the welding torch can be purchased at a retail chain. If you wish and have the necessary parts, you can do it yourself. Savvy innovators use an electric motor from car wipers, 2 bearings, 2 plates and a Ø 25 mm roller for this. The roller is installed on the motor shaft. Bearings are attached to the plates. They press themselves against the roller. Compression is carried out using a spring. The wire passes along special guides between the bearings and the roller and is pulled.

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

Pulling mechanism assembly

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

Homemade burner device

However, those who want to quickly produce a semi-automatic gun can buy a ready-made gun in a retail chain along with sleeves for supplying shielding gas and welding wire.

Balloon

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

Semi-automatic with your own hands. Video

You can learn about the layout, assembly, and testing of a homemade semi-automatic machine from this video.

A do-it-yourself inverter semi-automatic welding machine has undoubted advantages:

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

Comments:

Any tool store can currently offer a fairly large assortment of various welding machines in various price categories. The majority of welding units, up to 70%, are occupied by welding inverters, and the rest of the “welders” are transformer-type devices. Not all people can purchase an industrial product for electric welding work, and some want to do it themselves.

Home welding machine will not be able to perform complex tasks, but for small jobs the power will be enough.

What is electric welding

Connecting metal products to each other by heating the metal with an electric arc and then fusing it into a permanent seam is called electric welding. The main equipment in such a welding process is a welding machine, and the main tool for joining metal things is an electrode. The welding unit serves as a source of alternating or direct current, which, through an electrode, ignites an arc that melts the metal. Quality welded joint when welding with direct currents, it is significantly higher than the same connection made by alternating currents. The experience of an electric welder should not be discounted, although welding inverters that are popular today allow high-quality welding of metals almost the first time. That is why, for most of the various welding jobs, welding machines are used that use direct current in their work.

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The simplest welding machine: instructions

For small home welding jobs, you can assemble a homemade compact device with low power. This is, of course, not an inverter, but necessary thing. When solving the problem of creating a welding “assistant”, you can use various design features.

The simplest welding device is a welding transformer with two windings: mains and working. The network voltage is calculated for the mains voltage, usually 220-240 volts, and the working one is calculated for a reduced voltage from 70 to 45 volts, and the change in current usually occurs by changing the number of turns of the working winding and its taps. You can use old ones as iron for transformers. asynchronous motors or industrial step-down three-phase transformers such as TOZ, etc.

The primary winding must be designed for a 25-amp current, the secondary or working winding must be designed for 160 A. This is reflected in the cross-section of the wires used. For a rough estimate of the current load per 1 sq. mm we allow 10 A, for aluminum - 4 A. We determine the cross-sectional area of the transformer iron window in sq. cm, then find the number of turns of the windings if required quantity for one volt is defined as 48 divided by the cross-sectional area of the transformer iron window. Calculating the device is half the battle; the main thing is to assemble it.

The product created according to calculations is the simplest alternating current welding device; the design of the device depends on the materials used.

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Let's make a DC welding machine with our own hands

In order for alternating current welding machines to turn into direct current “welders,” it is necessary to limit the rate of change of current with a choke and rectify the alternating current with diodes or a rectifier bridge.

The diodes must correspond to an output current of 200 A and have sufficiently good cooling so that the first welding does not damage them. This fully applies to the throttle. The use of these devices in conjunction with an alternating current welding unit turns it into a direct current apparatus. Welding with DC electrodes becomes possible, and the range of welded metals expands. Becomes weldable stainless steel and cast iron. A welding machine can weld like an inverter, although the welder requires quite a lot of experience.

If you decide to assemble a semi-automatic welding machine with your own hands from an inverter, diagram and detailed instructions will become indispensable companions on the way to achieving your goal. The easiest way is to purchase factory semi-automatic devices such as Kedr 160, Kaiser Mig 300 with the required Ampere rating. But many people strive to do everything themselves. It's not that easy, but if you want to, you can achieve a positive result.

Mig, Mag, MMA welding requires the use of appropriate devices. Mig Mag is a semi-automatic welding process that is performed in an inert argon gas environment. Sometimes carbon dioxide is used for Mig Mag welding. MMA welding is called manual arc processing with electrodes on which a special coating is applied. If you are working with stainless steel, then MMA welding is carried out only with DC.

Since we are talking about how you can assemble a full-fledged semi-automatic machine based on an inverter with your own hands, you are not interested in MMA, but in Mig Mag welding.

To collect homemade apparatus, a worthy analogue for Kedr 160, Kaiser Mig 300, do it yourself, you will need a diagram, video instructions and necessary elements semi-automatic designs. These include:

Inverter. Determine its welding ability by selecting the supplied current. Typically, craftsmen assemble devices capable of delivering 150 Amps, 170 Amps or 190 Amps. The higher the Amps, the higher the ability of your welding device;
Feeding mechanism. We will tell you about it separately;
Burner;
Hose for supplying electrodes;
A spool of special wire. This attachment is easily attached to the structure in any way convenient for you;
Control unit for your welding unit.

Now regarding the feed mechanism for a semi-automatic machine and some important points.

He is responsible for supplying electrodes using a flexible hose to the welding point.
The optimal feed speed of the electrode wire corresponds to the speed of its melting at welding work with your own hands.
The quality of the seam you make with your own hands depends on the wire feed speed.
It is recommended to make a semi-automatic machine with the ability to adjust the speed. This will allow the semi-automatic machine to be adapted to different type electrodes used.
The most popular electrode wires have a diameter from 0.8 to 1.6 mm. It must be wound on a reel and charged the inverter.
If you provide fully automated feeding, you will not have to do it yourself, and therefore the time spent on welding activities will be significantly reduced.
The control unit is equipped with a control channel, which is responsible for stabilizing the current.
The behavior of Amperes, that is, the current of a semi-automatic device, is regulated by a special microcontroller. It performs its work in pulse-width operating mode. The voltage created in the capacitor directly depends on its filling. This affects the welding current parameters.

Preparing a semi-automatic transformer

In order for a self-made semi-automatic machine to work no worse than a welding machine like Kedr 160, Kaiser Mig 300, you need to understand the features of transformer preparation.

Wrap it with a copper strip. Its width should be 4 cm and thickness - 30;
Before this, the strip is wrapped with thermal paper. Suitable material used in cash registers. It is not difficult to purchase such paper;
In this case, the circuit does not allow the use of ordinary thick wiring, otherwise it will begin to overheat;
The secondary winding must be made by using three layers of tin at once;
PTFE tape is used to isolate each layer of sheet metal from each other;
At the output, you will need to solder the contact ends from the secondary winding with your own hands. This is necessary in order to increase current conductivity;
Be sure to include a fan in the inverter housing. It will serve as a blowing mechanism that reduces equipment overheating.

Inverter setup

There are no problems with the operation of Kedr 160 and Kaiser Mig 300. Cedar 160 and Kaiser Mig 300 are factory equipment that have excellent specifications. These semi-automatic machines function perfectly, allowing you to get the required number of Amperes - 160 Amperes, 170, 190 Amps, etc. It all depends on how you configure the device.

But if you decide to remake the inverter and make it a semi-automatic device, then the idea of buying Kedr 160, Kaiser Mig 300 should be thrown aside.

After completing work with the transformer, you should move on to the inverter. If you make the correct settings for the inverter itself, the modification will bring the desired result. Therefore, a homemade semi-automatic machine will function no worse than a ready-made Kedr 160 or Kaiser Mig 300 device.

Be sure to provide high-efficiency radiators used for rectifiers (input and output) and power switches. Without them, the device will not be able to work properly.
A temperature sensor should be installed inside the radiator housing, which heats up the most, to trigger it in case of overheating.
Connect the power part to the control unit and plug it into the working network.
When the indicator is activated, you should connect an oscilloscope to the wires.
Find bipolar impulses. Their frequency ranges from 40 to 50 kHz.
The time parameters between pulses are adjusted by changing the input voltage. The time indicator must correspond to 1.5 μs.
Make sure that the inverter produces square wave pulses on the oscilloscope. The edges should not exceed 500 ns.
When the device has passed the test, connect it to the power supply.
The indicator built into the semiautomatic device should produce 120 Amperes. Parameters can reach up to 170, 190 Amperes. But if the device does not show given value, you will have to go in search of the causes of low voltage in the wires.
Typically, this situation occurs when the voltage is less than 100 V.
Now we test the semi-automatic welding machine, starting the device with variable current. At the same time, constantly monitor the voltage on the capacitor.
We complete the testing by checking the temperature readings.
Check how the device behaves when loaded. Similar initial tests should be carried out with the Kedr 160 and Kaiser Mig 300. Although the Kedr 160 and Kaiser Mig 300 are factory semi-automatic machines from trusted manufacturers, it will never be superfluous to make sure of their professional suitability.
To test a homemade inverter or Kedr 160 with a Kaiser Mig 300, you need to connect a 0.5 Ohm load rheostat to the welding wires. Make sure this element can withstand a load greater than 60 Amps. The current parameters are monitored with a voltmeter.
If checking the semi-automatic device shows that the specified current value and the controlled value are different, the resistance will need to be changed. Do this until you achieve a positive result.

Assembling a device that will act as a full-fledged analogue for the Kedr 160 and Kaiser Mig 300 is not so simple, but it is possible. You yourself determine whether the semi-automatic device will produce 120 or all 190 Amperes. Make choosing a factory model easier. But their price is appropriate. The price of the same semi-automatic Kedr 160 Mig is from 27 thousand rubles. But the decision is yours to make.

I bought myself a welding inverter GYS IMS 1300
The thing is cool.
Lightweight, small, you can even carry it with you.
Cooks with a 2 mm electrode - whatever you want.
But they can’t cook the car
The metal of the car is thin - it burns holes.
We were looking for 1.6 mm electrodes, but there aren’t any in Chernigov, there might be some in Kyiv, but they haven’t called yet (I ordered to find them)
We suffered at home, but we couldn’t cook the metal in the Lada.

I went to a friend, he has a SEMI-AUTOMATIC with CO2.
I cooked it with it and really liked it.
Thin metal is also easy to weld, just pour it neatly.
I found a wire that cooks without gas - POWDER WIRE, I think that’s what it’s called.
He brought it, tried to cook it for her, without gas - it COOKED.
I immediately had an idea - what if I made such an installation at home?

I bought a windshield wiper motor at the market.
I ordered the toothed gear to be cut at the factory, hardened, and they did it.
I assembled a setup that feeds wire.
I bought a real nose, like one from a semi-automatic machine.

I connected the wire feeder to the Inverter and started testing.
RESULT:
Sometimes it is possible to catch a constant arc, somewhere around 20 Amperes, or 30 A.
But it scorches thin metal, and “SRET9” drops on thick metal, but the welding quality is terrible.
We managed to weld metal to metal. but it’s TERRIBLY ugly, an electrode would have turned out neater.

Further nuances: the wire feeds normally.
1. The first option was - the feed is fast, I set it to 60-70 A - it managed to feed and burn, and the arc is constant, but it cuts metal, the current is too high.
2. The second option - reduced the speed by 2 times - the optimal feed speed is at 15-20 Amps.
- I tried to weld thin metal (from the body of a Zhiguli) to 3 mm - I barely welded it. It looks terrible. A lot of drops and debris, but it holds strong)))
=====================================================================
Now questions for the experts:
1. If I did something UNEARTHLY, don’t scold me, I just didn’t know.
2. Should such a monster work?
3. maybe something in the feeder is wrong?
4. Maybe this type of welding cannot weld with such wire (0.9 mm flux cored wire)?
5. Sometimes I can’t create an arc, what’s the reason for this? (the feed goes on, but the wire is stuck and does not burn, you have to strike like an electrode)

ASYA - 422458106 (for those who are interested in communicating with such “uniques9)))

It’s easier to buy ready-made.
In principle, it is possible to weld with a semi-automatic device from a source intended for welding with a stick electrode (MMA mode, external static current-voltage characteristic - I-V characteristic - steeply falling - 15-20V/100A, or “bayonet9 - current source”). But this requires a feed mechanism with a feed rate dependent on the arc voltage. By the way, self-shielding wire is good, but expensive, so a protective gas (at least carbon dioxide, in no case food grade!) will not hurt!

I have a question.
Purely in theory, it should be cooked from an inverter, transformer, etc.
Question:
How is wire contact made?
My wire only contacts the COPPER tube at the output. That is, I attach the welding power to a copper tube through which the wire comes out.
How is it necessary?
Can contact also be made on rollers, serving?
Or should there be contact along the entire length, even in the spring along which the wire runs?

The fact is that sometimes the wire rests against the metal and creeps further, without combustion; it rests and creeps, but there is no arc.
That's what I'm suspicious about.
Maybe it's because I only have contact when I exit?
Maybe you need to make contact with the power supply 100%, if possible, along the entire length of the wire advance?

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

A good owner must have a semi-automatic welding machine, especially owners of cars and private property. You can always do small jobs with it yourself. If you need to weld a machine part, make a greenhouse, or create some kind of metal structure, then such a device will become an indispensable assistant in your personal household. Here a dilemma arises: buy or make it yourself. If you have an inverter, it’s easier to do it yourself. It will cost much less than buying in a retail chain. True, you will need at least basic knowledge of the basics of electronics, the availability of the necessary tools and desire.

Making a semi-automatic machine from an inverter with your own hands

It is not difficult to convert an inverter into a semi-automatic welding machine for welding thin steel (low-alloy and corrosion-resistant) and aluminum alloys with your own hands. You just need to have a good understanding of the intricacies of the work ahead and delve into the nuances of manufacturing. An inverter is a device that serves to lower the 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 - carbon dioxide. This guarantees a high-quality weld, 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 the negative influence of air components (oxygen and nitrogen) by shielding 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 supply hose;
carbon dioxide cylinder;
torch gun:
spool of wire.

Welding station design

Principle of operation

When connecting the device to an electric network, alternating current is converted into direct current. This requires a special electronic module, a high-frequency transformer and rectifiers.

The easiest way is to use the circuit diagram from Sanych, who long ago made such a semi-automatic machine 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 using this scheme, but also improved it. Here is the original source:

Diagram of a semi-automatic welding machine from Sanych

Semi-automatic Sanych

To make the transformer, Sanych used 4 cores from 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 busbar (number of turns 35+35). The rectifier was assembled using a full-wave circuit. For the switch I chose a paired biscuit. I installed the diodes on the radiator so that they would not overheat during operation. The capacitor was placed in a device with a capacity of 30,000 microfarads. The filter choke was made on a core from TS-180. The power part is put into operation using a TKD511-DOD contactor. The power transformer is installed TS-40, rewound to a voltage of 15V. The roller of the broaching mechanism in this semi-automatic machine has a Ø 26 mm. It has a guide groove 1 mm deep and 0.5 mm wide. The regulator circuit operates at a voltage of 6V. It is sufficient to ensure optimal feeding of the welding wire.

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

Inverter setup

To ensure high-quality operation of a semiautomatic device with small dimensions, it is best to use toroidal type transformers. They have the highest efficiency.

Transformer winding diagram

To make an inverter with your own hands, you can take a computer unit, which must be in working condition. The body needs to be strengthened by adding stiffeners. An electronic part is mounted in it, made according to Sanych’s scheme.

Wire feeding

Pulling mechanism assembly

Homemade burner device

However, those who want to quickly produce a semi-automatic gun can buy a ready-made gun in a retail chain along with sleeves for supplying shielding gas and welding wire.

Semi-automatic with your own hands. Video

You can learn about the layout, assembly, and testing of a homemade semi-automatic machine from this video.

A do-it-yourself inverter semi-automatic welding machine has undoubted advantages:

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

We make a semi-automatic welding machine with our own hands

A unit designed for welding products is considered to be a semi-automatic welding machine. Such devices can be various types and forms. But the most important thing is the inverter mechanism. It is necessary that it be of high quality, multifunctional and safe for the consumer. Most professional welders do not trust Chinese products and make the devices themselves. The manufacturing scheme for homemade inverters is quite simple. It is important to consider for what purposes the device will be manufactured.

There are inverters for:

Welding using flux-cored wire;
Welding with various gases;
Welding under a thick layer of flux;

Sometimes, to achieve a high-quality result and obtain an even weld, the interaction of two devices is necessary.

Inverter devices are also divided into:

Single-hull;
Double-hull;
Pushing;
Pulling;
Stationary;
Mobile, which includes a trolley;
Portable;
Designed for beginner welders;
Designed for semi-professional welders;
Designed for professional craftsmen;

What will you need?

A homemade device, the circuit of which is very simple, includes several main elements:

Mechanism with main function responsible for controlling the welding current;
Mains power supply;
Special burners;
Convenient clamps;
Sleeves;
Cart;

Scheme of welding using a semi-automatic device in a protective gas environment:

The master will also need:

A mechanism that provides wire feeding;
A flexible hose through which wire or powder will be supplied to the weld under pressure;
Bobbin with wire;
Special control device;

Principle of operation

The operating principle of the inverter includes:

Adjusting and moving the burner;
Control and monitoring of the welding process;

When the unit is connected to the electrical network, a conversion of alternating current to direct current is observed. For this procedure you will need an electronic module, special rectifiers and a high-frequency transformer. For high-quality welding, it is necessary that the future unit has parameters such as the feed speed of the special wire, current strength and voltage in identical balance. For these characteristics, you will need an arc power source that has current-voltage readings. The length of the arc must be determined by the given voltage. The wire feed speed directly depends on the welding current.

Homemade device diagram:

The electrical circuit of the device provides for the fact that the type of welding greatly influences the progressive performance of the devices as a whole.

Electrical diagram of a homemade device:

DIY semi-automatic - detailed video

Created plan

Any scheme of a homemade device provides a separate sequence of operation:

At the initial level, it is necessary to ensure preparatory purging of the system. It will accept the subsequent supply of gas;
The arc power source must then be started;
Feed wire;
Only after all actions have been completed will the inverter begin to move at the specified speed.
At the final stage, the seam should be protected and the crater welded;

An example of a homemade device implementation:

A homemade device must operate on the principle of converting high-frequency currents. In this case, the EMF conversion is excluded. Thanks to this, the Device can be significantly reduced in size and weight. But to spend high-quality repairs devices, you need to understand electrical engineering.

A story about a homemade semi-automatic machine

Preparing the transformer

Your attention must be paid to the feeding mechanism. Using this device, the electrode wire must be fed. Due to the fact that this mechanism breaks down most often, high-quality calculations should be made. It is important to note that an increase in current in most cases leads to fire of the electrode. This causes severe damage to the product. But if the current is very weak, then it will not be possible to make a full-fledged unit. The resulting weld will be unreliable. Therefore, at this stage of preparation it is necessary to correctly perform all calculations.

Power supply

Repair or fabrication of a structure includes a power source. Such a device can be a rectifier, inverter or transformer. It is this part that affects the volume and cost of the welder. Inverter power supplies are considered to be the most professional and high-quality devices.

Power supply diagram:

Control board

To create an inverter, a special control board is required. This device must have the following components installed:

A master oscillator including a galvanic isolation transformer;
The node with which the relay is controlled;
Blocks feedback, responsible for the mains voltage and supply current;
Thermal protection block;
Antistick block;

Control unit printed circuit board:

Case selection

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

Coil alignment

The primary windings are made in parallel. Secondary reels are connected in series. According to a similar circuit, the device is capable of accepting a current of up to 60 A. In this case, the output voltage will be equal to 40 V. These characteristics are ideal for welding small structures at home.

Cooling system

During continuous operation a homemade inverter can overheat greatly. Therefore, such a device requires a special cooling system. The most simple method To create cooling is to install fans. These devices must be attached to the sides of the case. Fans must be installed opposite the transformer device. The mechanisms are attached in such a way that they can work for extraction.

Cooling to be used in homemade device, can be removed from outdated computer equipment. To do more than just remove warm air, but also the supply of fresh oxygen - 20-50 holes are drilled in the mechanism body. The diameter of such holes must correspond to the diameter of the drill and be at least 5 mm.

Repair/modification of electrode wire feed speed device

Inverters are considered reliable devices. But if care is not taken care of, the devices may fail. The devices may require repairs. In most cases main reason is a regulator failure. When the first problems occur, the breakdown affects the further operation of the device. Therefore, in order to avoid future repairs, you should devote as much time as possible to high-quality assembly of the device.

The unit diagram includes a pressure roller. It is equipped with a special wire pressure level regulator. The unit also contains a wire feed roller, which has two small recesses. The welding wire should come out of them. The use of wire with a diameter of up to 1 mm is allowed. Immediately after the regulator there is a solenoid that controls the gas supply.

The regulator is considered a large element. It is secured with small bolts. Therefore, the fastening is extremely unreliable. The unit may warp, which may lead to malfunction. It is because of this reason that the device often breaks down and requires additional repairs.

DIY choke

In order to make a choke, you will need a transformer, an enamel wire with a diameter of more than 1.5 mm. Insulation is wound between the layers. Using an aluminum bus with dimensions of at least 2.5x4.5 mm, 24 turns are wound. The remaining ends of the bus remain 30 cm each. The core is laid using pieces of textolite with a gap of at least 1 mm. It is also allowed to wind the inductor on iron from an old tube color TV. But such a device can only have one coil. Such a device can stabilize the welding current. The finished product must output a minimum of 24 V at 6 A.

Welding torch

This device is designed to supply electrode wire, carbon dioxide and arc voltage to required area welding The purpose of the device is to close the circuit, which ensures the supply of welding wire to the shielding gas.

It is recommended to buy a standard type of cylinder. If carbon dioxide is used, then the use of a fire extinguisher cylinder is permitted. First, remove the horn from the device. To install the reducer, a special adapter is required, since the thread of the cylinder does not match the neck of the fire extinguisher. To move the cylinders you will need a cart.

The cart can be made by yourself. Also allowed to use ready-made structures. You can make single-level, two-level and three-level products. For convenience, tools and materials that will be needed for work are stored on the upper level. For easy movement, the cart includes wheels with a diameter of at least 5 cm.

Homemade cart with several variations:

Welding modes in carbon dioxide:

A semi-automatic device differs from a conventional device in its wire feed mechanism. Therefore, such a unit is considered the most complex device. Repair will be necessary if the feed mechanism breaks down.

Another useful option manufacturing

Converting a welding inverter into a semi-automatic machine

To make a semi-automatic machine from welding inverter– it is necessary to subject the device to some manipulations. The device is wrapped in copper strip with thermal paper winding. It is important to note that ordinary thick wire will not work. It will get very hot. The cooling system may not be able to cope with the load, which will lead to severe overheating of the device.

The secondary winding should consist of three layers of tin. Each layer should be carefully insulated. To do this, use fluoroplastic tape. The ends of the winding must be soldered together. This procedure allows you to increase the conductivity of currents.

Oscillogram of welding voltage and current on reverse and direct polarity:

Any homemade device does not respond well to the presence of dirt and dust. Therefore, such devices should be cleaned at least once every 4-6 months. The intensity of cleaning should depend on the number of uses. Otherwise, the device will have to be repaired annually.

Approximate modes for welding butt seams using a semi-automatic machine:

The main advantage of such devices is considered to be low weight. It is also possible to use both AC and DC power. The units can weld non-ferrous metals, as well as cast iron. The disadvantages include the low temperature range. Do-it-yourself semi-automatic welding cannot be used at temperatures below 15°C. Therefore, for cold regions and for winter period Such devices will not be suitable for the time being. Basically, such inverters are used outdoors in the summer or indoors. Homemade designs Perfect for welding small structures at home. For professional welding and for wide production, it is recommended to buy ready-made inverters.

How to convert a welding inverter into a semi-automatic machine for almost free

Inverters are widely used in home and garage foremen. However, welding with such a machine requires certain skills from the operator. The ability to “hold the arc” is required.

In addition, arc resistance is not a constant value, so the quality of the weld directly depends on the qualifications of the welder.

All these problems fade into the background if you work with a semi-automatic welding machine.

Design features and operating principle of the semi-automatic machine

A distinctive feature of this welder is that instead of replaceable electrodes, wire is continuously fed into the welding zone.

It provides constant contact and has less resistance compared to arc welding.

Due to this, a zone of molten metal is instantly formed at the point of contact with the workpiece. The liquid mass glues the surfaces together, forming a high-quality and durable seam.

Using a semi-automatic machine, any metals can be easily welded, including non-ferrous and stainless steel. You can master welding techniques on your own; there is no need to enroll in courses. The device is very easy to operate, even for a novice welder.

In addition to the electrical part - a high-power current source, the semi-automatic device has a mechanism for continuous supply of welding wire and a torch equipped with a nozzle for creating a gaseous environment.

They work with ordinary copper-plated wire in a protective inert gas environment (usually carbon dioxide). To do this, the cylinder with a reducer is connected to a special inlet fitting on the body of the semiautomatic device.

In addition, semi-automatic welding can be done in a self-protective environment, which is created using a special coating on the welding wire. In this case, no inert gas is used.

It is the ease of operation and versatility of the semi-automatic machine that makes the unit so popular among amateur welders.

Many kits feature a two-in-one function - a welding inverter and a semi-automatic machine in a common housing. An additional outlet is made from the inverter - a terminal for connecting the holder of replaceable electrodes.

The only serious drawback is that a high-quality semiautomatic device costs significantly more than a simple inverter. With similar characteristics, the cost differs by 3-4 times.

Therefore, home craftsmen strive, if possible, to convert the welding inverter into a semi-automatic device. We will tell you how to do this in the next article.

Do-it-yourself semi-automatic welding machine from an inverter

The basis of the future unit is a factory welding inverter with output current parameters of at least 150A. Some “Kulibins” recommend making changes to the inverter control module, since the current-voltage characteristic is falling normally, and for a semi-automatic device a different current-voltage characteristic curve is required.

To do this, you need to have a good understanding of how the device works. If the intervention is incorrect, the inverter will simply stop working. Therefore, the issue of modernizing the circuit is a separate conversation. Let's look at the mechanical part first.

To convert (more precisely, modify) the welding inverter into a semi-automatic device, we will need the following elements:

welding wire feeder
main tool - torch (gun)
abrasion-resistant hose (internal) for feeding welding wire
sealed hose for supplying inert gas to the welding zone
reel (reel) with welding wire
control unit for your semi-automatic machine.

The optimal solution would be to place the mechanical unit in a separate housing. A full-size box from system unit computer. Moreover, the power supply is used for the wire feed mechanism.

Trying on the size of the wire spool. There should be enough space left for a standard power supply and a hose connector.

The roller feed mechanism is developed based on the existing engine. A good donor is a windshield wiper motor with a standard gearbox.

We design the mechanism frame for it. The model is drawn on cardboard for trying on in real scale.

You can make the connector and hose with the burner yourself, but for safety it is better to purchase a ready-made kit. The welding wire feed mechanism is configured with the intended placement of the connector.

All components must be positioned level, opposite each other, for uniform wire feeding. Therefore, the rollers are carefully centered relative to the inlet fitting of the connector. We use ordinary ball bearings as guides for the feed mechanism.

We carry out pre-assembly feed mechanism in metal. We make fine adjustments and adjustments to the relative position.

Important! If there are any distortions, the wire will jam. This is very distracting during welding, and you can “screw up” the seam.

Since the welding wire will be live, the entire module, including the connector, must be insulated from the housing.

You can use textolite, durable plastic, or just a sheet of plywood with a thickness of at least 6 mm. We fix the structure on the body and check that there is no mutual contact between the metal parts.

The primary guide is made from a regular bolt, in which a longitudinal hole is drilled (using a conventional electric drill).

It turns out something like a wire extruder, only with free movement. A fluoroplastic cambric reinforced with a spring is put on the inlet fitting.

The pressure roller rods also need to be tension spring-loaded. The tension force is adjusted with a bolt.

We make a console for hanging a reel of wire from plastic pipe(drainage system) and thick plywood.

Provides sufficient strength and (which is especially important!) electrical insulation from a metal body.

We try on the reel and thread the wire into the feed mechanism. At this stage we finally adjust the gaps, mutual arrangement elements, free movement of wire.

After fine finishing, it is necessary to ensure that the nuts are locked. There are many ways - paint, lock nuts, metal sealant.

Semi-automatic mechanics control diagram

The motor speed is controlled by a PWM controller. When welding, it is important to accurately set the intensity of wire feed into the welding zone. Otherwise, you will not be able to ensure uniform melting of the weld metal.

The controller's variable resistor is installed on the front panel of the inverter. The next important part of the circuit is the control relay for the inert gas supply valve and engine start. Contact groups should be activated by pressing a button on the burner.

Moreover, the gas should be supplied two to three seconds earlier than the wire enters the welding zone.

Otherwise, the arc will ignite in an atmospheric environment, and the wire will simply burn out instead of melting.

To do this, a simple delay relay is assembled using an 815 transistor and a capacitor. For a pause of a couple of seconds, 200-250 µF is enough.

A regular car relay will do. Our power supply is 12 volts (computer power supply), so selecting components is convenient.

The valve itself is installed in a free space in the body. Any car locking device will do. In our case - air valve from GAZ 24.

Final assembly

We assemble all the controls on the front panel and assemble the body.

The PWM feed speed controller can be equipped with a digital indicator. By setting the speed, you can calibrate the readings, or simply remember the numbers for certain operating conditions. In any case, this will add comfort during use.

The semi-automatic welding inverter is ready. However, the falling current-voltage characteristic makes work inconvenient. There is no that vaunted smooth welding characteristic of a semi-automatic machine.

The goal is to make the output parameters stable in voltage, not current.

Many schemes have been developed for this. Look at the structural solution - the selection of elements occurs for various schemes inverters individually.

Another problem is the overheating protection sensor on the inverter triggering. This can be solved by installing an optocoupler pair. The temperature sensor is now used as a controller for the modified circuit.

Result:
A semi-automatic welding inverter will cost you three times less than a factory copy. The main thing is to study the diagram of your regular welder, and not be afraid to do the work yourself.

How to convert a semi-automatic welding machine from an inverter with your own hands - video instructions

Communities › Homemade products (garage auto industry) › Blog › Review of a semi-automatic welding machine Do-it-yourself. The final.

I present to you the final version of my semi-automatic welding machine or how to make a semi-automatic welding machine from an MMA welding inverter (welding with stick electrodes).

IN currently MMA inverter welding machines (for welding with stick electrodes) are very common; they produce direct current, weigh little and have good efficiency compared to transformers, and have quite affordable prices. There are also inverter semi-automatic MIG/MAG machines, they have the same advantages except for one thing - the price, based on this, I thought about how to make a semi-automatic machine from a regular inverter welder.
The beginning of a project to build a semi-automatic welding machine, or rather an attachment to an inverter, so that the inverter can be used in semi-automatic mode.
In our case, a good welding inverter is BRIMA ARC-250

The goal is to make it possible to use the MMA inverter in semi-automatic mode using available materials with a minimum budget.
1) To begin with, without reinventing the wheel, we purchased a sleeve with a Euro connector: EURO burner MB15AK Jingweitip 180A 3m CYCLONE.

Burner EURO MB15AK Jingweitip 180A 3m CYCLONE

2) One of the main elements of the PA is the tape drive; as a basis, we took a motor from the wipers from some kind of bucket, we also needed bearings and a Euro connector for connecting the sleeve.

After I assembled my tape drive, I accidentally came across an aliexpress that had a ready-made version and was not very expensive.

3) As a case for our attachment to the inverter, we took the case from an ancient computer and safely stuffed everything into it.

PA attachment diagram

That's all, the attachment for the inverter is ready!)))
Then the fun begins. As is known, the current-voltage characteristic (volt-ampere characteristic) for MMA and PA (MIG/MAG) machines is different; for machines for manual MMA welding, the current-voltage characteristic has a falling form, i.e. The device supports constant current. and for PA devices (MIG/MAG) the current-voltage characteristic has a rigid form, i.e. The device maintains constant voltage. No matter how much I searched, there is no information anywhere on the Internet on how to convert a conventional machine for welding with stick electrodes in PA, but having understood this issue a little, it turned out that not everything is so difficult...

alteration of the current-voltage characteristic on the inverter

Now our inverter has the ability to switch from welding mode with stick electrodes to PA mode.
The end result was something like this:

Since I am a certified welder, in short, I ask you not to judge strictly on the seam and quality of welding, but nevertheless, the device copes with its task and welds either thin (false) or thick metal.

You can also watch the video:

TOTAL: We assembled a set-top box and an MMA inverter to operate in PA mode.
APPROXIMATE PRICE:
Burner - 2500 rub.
Euro connector - 1000 rub.
PWM controller - 500 rub.
Bearings - 100 rub.
Electrical connector - 300 rub.
Little things - 100 rub.
Old trash - free)))
TOTAL approx. 4500 rub.

7 months Tags: semi-automatic from inverter