How to make DC welding from ordinary. Do-it-yourself semi-automatic welding inverter: diagram, photo, video. When is a semi-automatic welding machine used?

I bought myself a welding inverter GYS IMS 1300
Thing is awesome.
Lightweight, small, take it with you.
Cooks with a 2 mm electrode - anything.
But they can't weld the car
the metal of the car is thin - it burns holes.
We were looking for 1.6 mm electrodes, but not in Chernihiv, maybe in Kyiv, but they haven’t called yet (I ordered to find it)
We suffered at home, but we could not weld the metal in the Zhiguli.

I went to a friend, he has a SEMI-AUTO, with CO2 which.
I cooked them - I really liked it.
Thin metal is also easy to cook, just pours neatly.
I found a wire that cooks without gas - POWDER WIRE, it seems that's what it's called.
Brought it, tried to cook it, without gas - COOK.
I immediately had an idea - what if you make such an installation at home?

I bought a wiper motor in the market.
I ordered a toothy gear cut at the factory, hardened - done.
Assembled the installation that feeds the wire.
I bought a real nose, like a semi-automatic.

I connected the wire feeder to the Inverter and started testing.
TOTAL:
Sometimes it is possible to catch a constant arc, somewhere at 20 Amperes, or at 30 A.
But the thin metal is weeded, and on the thick one drops “CPET9” but the welding quality is terrible.
It was possible to weld metal to metal. but TERRIBLY ugly, the Electrode would have turned out more accurately.

Further nuances: the wire is fed normally.
1. The first option was - the feed was fast, set 60-70 A - it managed to both supply and burn, and the arc is constant, but it cuts the metal, too much current.
2. The second option - the speed is reduced by 2 times - the optimal feed rate is at 15-20 Amps.
- tried to weld thin metal (from the body of the Zhiguli) to 3 mm - barely welded. Looks terrible. A bunch of drops, garbage, but holding on tight)))
=====================================================================
Now for the experts:
1. If I did something UNEARTHLY - do not scold, I just did not know.
2. Should such a monster work.
3. maybe something in the feeder is wrong?
4. Maybe welding of this type cannot weld with such a wire (cored wire 0.9 mm)?
5. Sometimes I can’t create an arc, what is the reason for this. (the feed is on, but the wire rested and does not burn, you have to strike like an electrode)

ASYA - 422458106 (for those who are interested in talking with such "unique"9)))

Easier - buy ready-made.
Cooking semi-automatically from a source intended for welding with a stick electrode (MMA mode, external current-voltage static characteristic - VAC - steeply falling - 15-20V / 100A, or “bayonet9 - current source), in principle, is possible. But this requires a feed mechanism with a feed rate dependent on the arc voltage. By the way, self-shielded wire is good, but expensive, so shielding gas (at least carbon dioxide, by no means food!) Doesn't hurt!

I got a question.
Purely in theory, it should be cooked from an inverter, transformer, etc.
Question:
How is wire contact made?
My wire is in contact only with the COPPER tube at the outlet. That is, I attach the Power from welding to the Copper tube, through which the wire climbs out.
And how is it necessary?
Can contact also be made on rollers, feeders?
Or should the contact be in general along the entire length, even in the spring along which the wire goes?

The fact is that sometimes the wire rests on the metal and creeps further, without combustion, rested and crawls, but there is no arc.
That's what I suspect.
Maybe this is due to the fact that I have contact only when I exit?
maybe you need to make contact with the power supply, if possible, make 100%, along the entire length of the wire advance?

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 owners of cars and private property. You can always do small things with him. If it is necessary to weld a machine part, 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 trading 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 the subtleties well future work and delve into the nuances of manufacturing. An inverter is a device that reduces electrical voltage to 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 is being transformed alternating current into permanent. 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 current-voltage 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. 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 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 TS-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 machine 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 ensure optimum welding wire feed.

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 ensure high-quality operation of the 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 correctly assembled inverter when performing welding operations makes it possible to regulate the current in a wide range: from 20 to 160A, and the choice of the operating current strength 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.

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 kinds and forms. But the most important 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, making devices on their own. 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 with flux-cored wire;
Welding on various gases;
Welding under a thick layer of flux;

Sometimes for a high-quality result and getting an even weld interaction between the two devices is required.

Also inverter devices are 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 be required?

A home-made apparatus, the scheme of which is very simple, includes several main elements:

A mechanism with a main function responsible for controlling the welding current;
Mains power supply;
Special burners;
Convenient clips;
Sleeves;
Cart;

Scheme of welding using a semiautomatic device in a protective gas environment:

The master will also need:

The mechanism that provides the wire feed;
Flexible hose, through which the wire or powder will flow to the weld under pressure;
Bobbin with wire;
Special control device;

Principle of operation

The principle of operation of the inverter includes:

Adjustment and movement of the burner;
Control and monitoring of the welding process;

When connecting the unit to electrical network there is a conversion of alternating current to direct current. For this procedure, you will need an electronic module, special rectifiers and a transformer with a high frequency. For high-quality welding, it is necessary for the future unit to have such parameters as the feed rate of a special wire, current strength and voltage be 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 is directly related to the welding current.

Scheme homemade device:

The electrical circuit of the device provides for the fact that the type of welding strongly affects the progressive performance of the apparatus as a whole.

Wiring diagram of a homemade device:

Do-it-yourself semiautomatic device - detailed video

Created plan

Any scheme of a home-made device provides for 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.
At the final stage, the seam should be protected and the crater should be filled;

An example of the implementation of a homemade device:

A home-made device should work on the principle of converting high-frequency currents. In this case, the EMF conversion is excluded. Due to this, the Device can be significantly reduced in size and weight. But to pass quality repair devices, it is necessary to understand electrical engineering.

A story about a homemade semi-automatic

Transformer preparation

Your attention must be paid to the feed mechanism. Using this device, the electrode wire must be fed. Due to the fact that this mechanism breaks down most often, qualitative calculations should be made. It is important to consider that an increase in current in most cases leads to ignition of the electrode. This results in severe damage to the product. But if the current is very weak, then it will not work 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 the calculations.

Power supply

Repair or fabrication of the structure includes a power source. Such a device can be a rectifier, inverter or transformer. It is this detail 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 circuit:

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";

Control unit printed circuit board:

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.

The cooling that will be used in a homemade device can be removed from outdated computer equipment. In order to make not only the removal of warm air, but also the supply of fresh oxygen, 20-50 holes are drilled in the mechanism case. The diameter of such holes must correspond to the diameter of the drill and be at least 5 mm.

Repair / modification of the electrode wire feed speed device

Inverters are considered reliable devices. But with careless care, the devices can fail. Devices may need to be repaired. In most cases, the main cause is a broken regulator. If 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 the high-quality assembly of the device.

The scheme of the unit includes a pressure roller. It is equipped with a special wire pressure level regulator. Also in the unit there is a wire feed roller, in which there are two small recesses. 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 is a solenoid that controls the gas supply.

The regulator is considered a large element. It is fixed with small screws. Therefore, the fastening is extremely unreliable. The unit may tilt, which may cause a malfunction. It is because of this reason that the device often breaks down and requires additional repairs.

Throttle do-it-yourself

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. With the help of an aluminum tire with dimensions of at least 2.5x4.5 mm, 24 turns are wound. The remaining ends of the tire 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 a choke on iron from an old tube color TV. But only one coil can be put on such a device. Such a device can stabilize the welding current. The finished product must provide a minimum of 24V at 6A.

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 the welding wire to the shielding gas.

The cylinder is recommended to buy a standard type. If carbon dioxide is used, the use of a fire extinguisher cylinder is allowed. Previously, the horn is removed from the device. To install the reducer, a special adapter is required, since the cylinder thread does not match the fire extinguisher neck. You will need a trolley to move the cylinders.

The trolley can be made by yourself. Also allowed to use finished structures. You can make single-level, two-level and three-level products. For convenience, the top level stores tools and materials that will be needed for work. For convenient movement, the trolley 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 a wire feed mechanism. Therefore, this unit is considered the most complex device. Repair will be necessary in the event of a feeder failure.

Another useful option

Alteration of the welding inverter into a semiautomatic device

To make a semi-automatic welding inverter– it is necessary to subject the device to some manipulations. The device is wrapped with a copper strip wrapped with thermal paper. It is important to note that an ordinary thick wire will not work. It will get very hot. The cooling system may not be able to cope with the set 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 isolated. To do this, use fluoroplastic tape. The ends of the winding must be made 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 apparatus poorly perceives 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 applications. Otherwise, the device will have to be repaired annually.

Approximate modes of welding butt welds using a semiautomatic device:

The main advantage of such devices is considered to be low weight. It is also possible to use both AC and DC. Units can weld non-ferrous metals, as well as cast iron. The disadvantages include the low temperature range. Semi-automatic welding do not use with your own hands at temperatures below 15 ° C. Therefore, for cold regions and for winter period time such devices will not work. 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 semiautomatic device for almost free

Inverters are widely used in household and garage craftsmen. However, welding with such an apparatus requires certain skills from the operator. You need the ability to "hold the arc."

In addition, the arc resistance is a variable value, so the quality of the seam 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 principle of operation of the semiautomatic device

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

It provides constant contact and has less resistance than 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, forming a high-quality and durable seam.

With the help of a semi-automatic device, any metals are easily boiled, including non-ferrous and stainless steel. You can learn the welding technique on your own, there is no need to sign up for 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 continuous welding wire feed mechanism and a torch equipped with a nozzle to create a gaseous environment.

They work with ordinary copper-plated wire in a protective inert gas (usually carbon dioxide). To do this, a cylinder with a gearbox 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, inert gas is not used.

It is the ease of operation and versatility of the semiautomatic device that makes the unit so popular among amateur welders.

In many kits, the two-in-one function is implemented - a welding inverter and a semiautomatic device in a common housing. An additional tap is made from the inverter - a terminal for connecting the holder of replaceable electrodes.

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

Therefore, home craftsmen seek, if possible, to convert the welding inverter into a semi-automatic device. How to do this - we will tell in the next article.

Do-it-yourself welding semiautomatic device 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 nominal current-voltage characteristic is falling, and a different I-V curve is needed for a semiautomatic device.

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 upgrading the scheme is a separate conversation. Let's look at the mechanical part first.

To convert (more precisely, refine) a welding inverter into a semiautomatic device, we need the following elements:

wire feeder
the main tool is a burner (gun)
abrasion resistant hose (internal) for welding wire feed
sealed hose for supplying inert gas to the welding zone
bobbin (coil) with welding wire
control unit for your semi-automatic.

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

We try on the size of the bobbin with wire. There should be enough space for the stock PSU and hose connector.

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

Under it, we design the frame of the mechanism. The layout is drawn on cardboard, for fitting in real scale.

You can make your own connector and hose with a torch, but for safety, it is better to purchase a ready-made kit. The wire feeder is configured with the intended placement of the connector.

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

We carry out pre-assembly metal feeder. We make fine adjustment and adjustment of the relative position.

Important! With any distortions, the wire will wedge. This is very distracting during welding, and you can "screw up" the seam.

Since the welding wire will be energized, 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, check the absence of mutual contact of metal parts.

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

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

The pressure roller bars also need to be spring-loaded in tension. The tension force is adjustable with a bolt.

The console for hanging the bobbin with wire is made of plastic pipe(drainage system) and thick plywood.

Provides sufficient strength and (which is especially important!) electrical isolation from the metal case.

We try on the coil, we thread the wire into the feed mechanism. At this stage, we finally adjust the gaps, the relative position of the elements, the free movement of the wire.

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

Semi-automatic control scheme

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

The variable resistor of the controller is mounted 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 triggered by pressing the button on the burner.

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

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

For this, a simple delay relay is assembled on an 815 transistor and a capacitor. For a pause of a couple of seconds, 200-250 microfarads is enough.

The relay will fit the usual car. Our power supply is 12 volts (computer PSU), so it is convenient to select components.

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

final assembly

We assemble all the controls on the front panel, assemble the case.

PWM feed rate 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, it will add comfort when using.

The semiautomatic welding inverter is ready. However, the falling current-voltage characteristic makes operation inconvenient. There is no that vaunted smoothness of welding, characteristic of a semiautomatic device.

The task is to make the output parameters stable in voltage, and not in 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 operation of the overheating protection temperature sensor on the inverter. This is solved by installing an optocoupler. The temperature sensor is now used as a controller for the modified circuit.

Outcome:
A semi-automatic welding inverter will cost you three times less than a factory copy. The main thing is to study the scheme 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 instruction

Communities › Homemade (garage car industry) › Blog › Overview of a semi-automatic welding machine With your own hands. The final.

I present to you the final version of my welding semiautomatic device or how to make a semiautomatic device from an MMA welding inverter (stick electrode welding).

At the moment, MMA inverter welding machines (for welding with stick electrodes) are very common, they give out direct current, weigh little and have good efficiency, compared to transformers, and have quite affordable prices. There are also MIG / MAG inverter semiautomatic devices, they have the same advantages, except for one thing - the price, based on this, I thought about how to make a semiautomatic device from a conventional inverter welder.
Start of the semi-automatic construction project welding machine, or rather, a prefix to the inverter so that the inverter can be used in semi-automatic mode.
In our case, a good welding inverter BRIMA ARC-250

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

Burner EURO MB15AK Jingweitip 180A 3m CYCLONE

2) One of the main elements of the PA is a tape drive, for the basics we took a motor from the wipers from some kind of bucket, we also needed a bearing time and a euro connector to connect the sleeve.

after I assembled my tape drive, I accidentally stumbled upon aliexpress for a ready-made version and not very expensive.

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

Scheme of the prefix PA

That's all the prefix for the inverter is ready!)))
Then the most interesting begins. As you know, the current-voltage characteristic (CVC) for MMA and PA (MIG / MAG) devices is different, for MMA manual welding machines, the CVC has a falling form, i.e. the device maintains a constant current. and for PA devices (MIG / MAG) the CVC has a hard form, i.e. the device maintains a constant voltage. No matter how much I searched, there is no information anywhere on the Internet on how to convert a conventional stick electrode welding machine into PA, but after understanding this issue a little, it turned out to be not so difficult ...

alteration of the CVC on the inverter

now our inverter has the ability to switch from stick electrode welding mode to PA mode.
In the end it turned out something like this:

Since I am a “certified” welder, shorter than a hand-ass, I ask you not to judge strictly for the seam and the quality of welding, but nevertheless, the device copes with its task and welds even thin (falge) even thick metal.

You can also watch the video:

TOTAL: We have assembled a prefix and an MMA inverter to work in PA mode.
APPROXIMATE PRICE OF THE QUESTION:
Burner - 2500 rubles
Euro connector - 1000 rubles
PWM controller - 500 rubles
Bearings - 100 rubles
Electrical connector - 300 rubles
Little things - 100 rubles
Old junk - for free)))
TOTAL approx. 4500 rub.

7 months Tags: inverter semi-automatic

Most welding machines, especially homemade ones, are far from perfect. We offer a scheme for fine-tuning a home-made welding machine from "change" to "permanent" with your own hands and you can use electrodes of any type ( see fig. one).

Rice. 1 Scheme of a welding machine with a highly efficient inductive-capacitive filter that smooths out the ripple of the rectified voltage.

Let's go through the diagram.

Choke L.

The core for it is taken from the choke of urban lighting lamps 1N400N37-110. When removing the old windings, it is necessary to save the cardboard spacers, which provided a gap between the main and closing parts of the core (Fig. 2).

When reassembling, they are installed in place. The new winding is wound on only one side rod - three layers of a copper bus with a section of 4x6 mm, evenly spaced along the entire length of the core. The beginning of the inductor winding is connected to the block of capacitors C1 ... C6, and the end of the winding is connected to the “+” terminal (Fig. 1).

Rectifier and filter capacitor bank.

Diodes U01 ... U04 type D161-320 or similar, designed for average rectified current - above 250 A and reverse voltage - at least 200 V, are mounted on standard cast radiators-coolers, which must be isolated from each other and from the body of the welding apparatus with textolite plates. Capacitors 31 ... 56 - electrolytic, type K50-3 or K50-7 two-section 250/290 (150 + 150 microfarads). The total capacitance of the block of capacitors is 1800 microfarads. It is most convenient to install them in one row on a textolite plate 4 ... 6 mm thick.

Welding current regulator R (“ballast rheostat”).

Made from one section of the limiting resistance of the bridge crane DEK-256 (Fig. 3).

This resistance is ceramic pipe with a shaped spiral groove on the outer surface, in which a tire made of a material with a high resistivity, with a cross section of about 20 mm2.

You can buy a semi-automatic welding machine ready-made, but there are always people who try to make it with their own hands. This is not easy to do, but those who really want to assemble a semiautomatic device with their own hands will have to prepare all the necessary components in advance.

To make a semi-automatic welding machine from an inverter, you will need tools and materials:

an inverter that is capable of delivering a current of about 150 A;
feeder;
burner;
flexible hose;
wire spool, with some design changes;
welding inverter;
Control block.

The feeder in this case deserves special attention: with its help, the electrode wire is fed through a flexible hose to the welding point. Ideally, the wire feed speed should match the melting speed consumable. The wire feed speed is very important for the welding process: the quality of the weld depends on it. It is necessary to provide for the possibility of speed control for the possibility of working with electrode wire different sizes from various materials. The most commonly used wire of the following diameters: 0.8 mm, 1 mm, 1.2 mm, 1.6 mm. It is wound on coils and the welding inverter is charged. Fully automatic wire feed to the welding torch significantly reduces the time spent on work.

The control unit of the semi-automatic welding machine has a control channel that stabilizes the current. The action of the current is controlled by the microcontroller in the pulse-width mode. The voltage on the capacitor directly depends on the filling of the pulse-width mode. It is this voltage that affects the strength of the welding current.

The subtleties of the transformer

There are small subtleties in the preparation of the transformer. The transformer must be wrapped with a copper strip (width - 40 mm, thickness - 30). First, the strip must be wrapped with thermal paper (suitable from cash register). Winding a simple thick wire in this case is excluded, since it will heat up.

The secondary winding should consist of three layers of tin. It is necessary to isolate the layers from each other with fluoroplastic tape. At the output, it is necessary to solder the contact ends of the secondary winding. This is done in order to increase the conductivity of currents. It is imperative to provide for blowing by a fan in the inverter housing.

Back to index

How to set up the inverter?

If you decide to make a semiautomatic device with your own hands, first you need to de-energize the power unit. By the way, for the input and input rectifiers, as well as for power switches (previously soldered to copper substrates), the power unit must be provided good radiators. In the case of the most heated radiator, it is necessary to place a temperature sensor. Now the power unit is connected to the control unit and connected to the network. When the indicator lights up, you need to connect the oscilloscope Out1, Out2 to the wires. Now find bipolar pulses, the frequency of which should be 40-50 kHz. The time between them is corrected by changing the input voltage. The time value should be 1.5 µs.

The pulses on the oscilloscope should be rectangular with fronts no more than 500 ns. After checking the inverter, connect it to the mains. The indicator of the semi-automatic welding machine should show 120 A, if this inscription on the indicator does not light up, then it is necessary to look for and eliminate the cause of low voltage in the welding wires. This situation occurs if the voltage is less than 100 V. After that, it is required to test the welding inverter by changing the current (with constant monitoring of the voltage on the capacitor). Then you can check the temperature.

After the welding inverter has been tested, it is necessary to check how it behaves under load. To do this, a 0.5 Ohm load rheostat is included in the welding wires, which must withstand a current of more than 60 A. In this state, the current is controlled using a voltmeter.

If there are discrepancies between the set value of the current and its controlled value, it will be necessary to select the resistance until a match is reached.

Back to index

Rules for using a welding inverter

By default, when you start the inverter, the controller will automatically set the current size. If all the steps indicated earlier are performed correctly, then the welding current will be 120 A. If it suddenly turns out that eights appear on the indicator, this will indicate a malfunction. Such malfunctions occur when the voltage in the welding wires does not rise more than 100 V. If this happens, then you will have to look for and fix the malfunction.

When everything is done correctly, a number should be displayed in place of the eights, indicating the amount of the given current. Using the buttons, this value can be changed, depending on what value of welding current is required in each specific case. The interval in which it is possible to change the current value varies from 20 A to 160 A.

It is possible to control the temperature of the inverter during the whole process. To do this, press both buttons at the same time. After that, it will be possible to observe the change in the temperature of the radiator, the data of which will be displayed on the indicator. Normally, the temperature of the heatsink should not exceed 75°C. If the temperature rises more than 75°C, it will immediately be displayed on the indicator, and the inverter will start beeping intermittent type. If this happens, the set current will automatically decrease to 20A. Although the current will be sharply reduced, the inverter will continue to work. This beep will sound until the display temperature returns to normal.

The indicator may give an error code Ert: this will happen in the event of a breakdown or short circuit of the temperature sensor.

In this case, in the same way, the set current will be reduced to 20 A.

Any welder knows about the advantages of a semiautomatic device over manual electric welding. Due to their high prevalence and low cost, MMA inverters are in the arsenal of many craftsmen. But with MIG welding, the matter is different - these devices are more expensive. But, there is a way out - you can make a semi-automatic device from an inverter with your own hands. If you delve into this issue, the matter will not be so difficult.

There are fundamental differences between MMA and MIG welding. To operate the semiautomatic device, you need carbon dioxide (or a mixture of carbon dioxide and argon) and an electrode wire, which is supplied to the welding site through a special hose. Those. the very principle of semi-automatic welding is more complicated, but it is universal and its use is justified. What is needed for the operation of a semi-automatic device:

wire feeder;
burner;
hose for wire and gas supply to the heating pad;
current source with constant voltage.
And to turn a welding inverter into a semiautomatic device, you need a tool, time and desire.

Training

Making a semi-automatic welding machine at home begins with work planning. There are two options for making MIG welding from an inverter:

Completely make a semi-automatic welding machine with your own hands.
To remake only the inverter - the feeding mechanism is ready to be purchased.

In the first case, the cost of parts for the feeder will be about 1000 rubles, excluding work, of course. If the factory semiautomatic device includes everything in one case, then the home-made one will consist of two parts:

Welding inverter.
Drawer with feeder and wire reel.

First, you need to decide on the case for the second part of the semiautomatic device. It is desirable that it be light and roomy. The feed mechanism must be kept clean, otherwise the wire will be jerky, in addition, periodically you need to change the spools and adjust the mechanism. Therefore, the box should be easy to close and open.

The ideal option is to use the old system unit:

neat appearance - special significance it doesn’t, but it’s much nicer when the insides of the homemade product don’t stick out and the semi-automatic device from the MMA inverter looks good;
light, closed;
the case is thin - it is easy to make the necessary cutouts;
the gas valve and the wire feed drive operate on 12 volts. Therefore, a power supply from a computer is suitable, and it is already built into the case.

Now you need to estimate the size and location of future parts in the case. You can cut out approximate layouts from cardboard and check their relative position. After that, you can start work.

The best option for electrode wire is a coil weighing 5 kg. Its external diameter is 200 mm, internal - 50 mm. For the axis of rotation, you can use sewer PVC pipe. Its outer diameter is 50 mm.

Burner

Homemade semi-automatic must be equipped with a burner. You can make it yourself, but it is better to buy a ready-made kit, which includes:

Burner with a set of tips of different diameters.
Supply hose.
Euro connector.

A normal burner can be purchased for 2-3 thousand rubles. Moreover, the device is homemade, so you can not chase expensive brands.

What to look for when choosing a kit:

what welding current is the torch designed for;
the length and rigidity of the hose is the main task of the hose, to ensure the free flow of the wire to the torch. If it is soft, any kink will slow down the movement;
springs near the connector and burner - they prevent the hose from breaking.

Feeder

The electrode wire must be fed continuously and evenly - then the welding will turn out to be of high quality. The feed rate must be adjustable. There are three options for how to make a device:

Buy completely finished mechanism assembled. Expensive, but fast.
Buy feed reels only.
Do everything with your own hands.

If the third option is chosen, you will need:

two bearings, guide roller, tension spring;
wire feed motor - a motor from wipers is suitable;
metal plate for fastening the mechanism.

One pressure bearing - it must be adjustable, the second serves as a support for the roller. Manufacturing principle:

holes are made on the plate for the motor shaft and for mounting bearings;
the motor is fixed behind the plate;
a guide roller is put on the shaft;
bearings are fixed at the top and bottom;

Bearings are best placed on metal strips - one end is bolted to the main plate, and a spring with an adjusting bolt is connected to the other.

The made mechanism is placed in the body so that the rollers are located in line with the connector for the burner, i.e. so that the wire does not break. Before the rollers, you need to install a rigid tube to align the wire.

Implementation of the electrical part

For this you will need:

two automotive relays;
diode;
PWM controller for the engine;
capacitor with transistor;
idle solenoid valve - for supplying gas to the burner. Any VAZ model will do, for example, from the eight;
wires.

The wire and gas feed control scheme is quite simple and is implemented as follows:

when the button on the burner is pressed, relay No. 1 and relay No. 2 are activated;
relay No. 1 turns on the gas supply valve;
relay No. 2 is paired with a capacitor and turns on the wire feed with a delay;
wire pulling is done by an additional button bypassing the gas supply relay;
to remove self-induction from solenoid valve, a diode is connected to it.
It is necessary to provide for the connection of the burner to power cable from the inverter. To do this, next to the euro connector, you can install a quick connector and connect it to the burner.

The semi-automatic device has the following sequence of work:

The gas supply is turned on.
After a short delay, the wire feed is switched on.

Such a sequence is needed so that the wire immediately enters the protective environment. If you make a semi-automatic without delay, the wire will stick. To implement it, you will need a capacitor and a transistor through which the engine control relay is connected. Operating principle:

voltage is applied to the capacitor;
it is charging;
current is applied to the transistor;
the relay turns on.

The capacitance of the capacitor must be selected so that the delay is approximately 0.5 seconds - this is enough to fill the weld pool.

After assembly, the mechanism needs to be tested, and the manufacturing process can be seen on the video.

Alteration of the inverter

To make a semiautomatic device from a conventional inverter with your own hands, you will have to slightly redo its electrical part. If you connect the MMA inverter to the assembled case, you will be able to cook. But at the same time, the quality of welding will be far from the factory semiautomatic device. It's all about the CVC - current-voltage characteristics. The arc inverter produces a falling characteristic - the output voltage floats. And for the correct operation of the semiautomatic device, a rigid characteristic is required - the device maintains a constant voltage at the output.

Therefore, in order to use your inverter as a current source, you need to change its CVC (voltage characteristic). For this you will need:

toggle switch, wires;
variable resistor and two constant;

It is quite easy to get a hard characteristic on an inverter. To do this, you need to put a voltage divider in front of the shunt that controls the welding current. For the divider, fixed resistors are used. Now you can get the necessary millivolts, which will be proportional to the output voltage, and not the current strength. There is only one minus in such a scheme - the arc turns out to be too rigid. To mitigate it, you can use a variable resistor, which is connected to the divider and the output of the shunt.

The advantage of this approach is that the arc stiffness adjustment appears - such a setting is only in professional semi-automatic machines. A toggle switch switches the inverter between MMA and MIG modes.

Thus, converting an MMA inverter into a semiautomatic device, although not an easy task, is quite feasible. At the output, it turns out a device that is not inferior to the factory ones in terms of its characteristics. But it is also much cheaper. The cost of such an alteration is 4-5 thousand rubles.

A semi-automatic welding device for domestic needs can be purchased in a ready-to-use form or completely assembled with your own hands. A home-made semiautomatic device will cost the performer much cheaper, but its assembly will require certain skills in working with electrical equipment. Appearance such a welded device is shown in the figure below.

For everyone who wants to make a semiautomatic device from an inverter with their own hands, we recommend that you first familiarize yourself with the device of this unit and the features of the functioning of its modules.

What you need to remake the inverter

Before you make a semi-automatic welding machine with your own hands, it will be necessary to prepare the following functional modules and spare parts that provide the required configuration of prefabricated equipment:

An old inverter unit, designed for a welding current of about 150 Amperes;
Another working unit of the future semiautomatic device is the so-called "burner";
A special feed mechanism with which it will be possible to organize the delivery of welding wire to the place of work;
Hoses that provide the supply of wire and shielding gas to a home-made welding unit (more precisely, to the production area of working operations);
A reel redesigned for new needs with a special wire placed on it;
A separate electronic module that controls the operation of the entire home-made device (including a converter transformer).

A complete set of nodes and modules required for a semiautomatic device can be found in the figure below.

Unit device

Consider the most important parts of do-it-yourself inverter-made units in more detail.

Consumable supply unit and torch

Particular attention should be paid to the complete alteration of the wire feeder, which will have to move inside the flexible hose, when picking up spare parts.

To obtain a high-quality and accurate weld, the wire feed speed must be synchronized with the melting rate of its working part.

Since the use of several types of wire made of different materials and having different diameters is allowed in semi-automatic welding, the rate of its arrival must necessarily be a variable value. It is this opportunity that should be provided by the so-called "supply" of consumables, which is organized in accordance with general requirements to any inverter unit.

When arranging semi-automatic scheme most often used wire with sections of 0.8, 1.0, 1.2 and 1.6 mm. Immediately before starting work, it is wound on pre-prepared coils, which are fixed on the elements of the unit using the simplest fasteners. Semi-automatic welding involves feeding the wire "self-propelled", which significantly reduces the time of all operations and increases the efficiency of these procedures.

The burner used in the semi-automatic device can be taken entirely from an idle welding machine of the same type or made independently at home. We’ll make a reservation right away that making a burner with your own hands is a very difficult task, requiring the performer to have certain experience and skills in the manufacture of such devices.

Electronic control module

The electrical circuit of the semi-automatic welding machine is shown in the figure below.

The basic element of the semi-automatic control unit is a microcontroller responsible for selecting the load mode and for stabilizing the output current. In addition, the electronic unit includes the following mandatory components and parts:

Rectifier bridge on semiconductor diodes of high power;
Key transistor circuits;
Additional winding transformer;
Correction chokes and inductors.

Particular attention in the composition of the electronic module should be given to winding inductive products.

A simplified version of the inverter unit is known, which is commonly called the “device from Sanych”. Its diagram is shown in the figure below.

Transformer

Another critical node of a semiautomatic device, made with your own hands from an old welding device, is a transformer, which can be taken from the same inverter (taking into account a slight alteration).

To ensure the required characteristics of the inverter transformer, fully suitable for a semi-automatic device, it is necessary to rewind the old primary coil with a copper strip coated with a layer of heat-resistant paper.

Important! Such transformers cannot be wound with ordinary thick copper wire, since they will become very hot in the mode of high current loads.

The secondary winding of the old transformer product should also be slightly modified. To do this, you will need to do the following operations:

First you need to wind a coil consisting of 3 layers of tin strips, each of which is insulated with a fluoroplastic tape;
Next, the ends of the old and newly wound winding must be soldered, which will ensure high conductivity of the entire coil;
It is also necessary to provide in the set of elements from which the semiautomatic device is assembled, a small fan (it is intended for additional cooling of the device).

As such a cooling device installed in welding units, a fan from a failed old PC can be used.

Assembly of the unit

Before you make a semi-automatic machine with your own hands, be sure to take care of checking all the necessary parts of the old inverter. In addition, in order to improve the thermal regime of the future device, it is necessary to provide additional radiators on which rectifiers and power diode switches are mounted (photo below).

Additional Information. In the spaces where the radiator blocks are to be placed, it is necessary to provide thermal sensors that record the temperature in this part of the device.

Upon completion of all the above procedures, you should proceed to docking the power module with the electronic control unit, after which you can try to connect it to the network and check it in operation.

Inverter setting

To carry out this mandatory procedure, first of all, it is necessary to connect the oscilloscope probes to the output terminals of the inverter converter, through which it will be possible to investigate the form of intermediate signals.

Note! On the screen of the oscilloscope, electrical pulses with a frequency of about 40-50 kHz should be observed (see the figure below).

The time between individual bursts of such pulses should be equal to 1.5 µs (it can be adjusted by changing the input voltage). The magnitude of the control potential applied to the input of the converter is usually measured using an electronic voltmeter.

In the process of tuning the conversion system, it is also necessary to monitor the shape of the pulses observed at the output, which should approach a rectangular shape with rises no longer than 500 ns. If all the parameters listed above comply with the standard values, you can proceed to setting up the load part of the inverter device.

The maximum current generated at the output of the operating unit should be about 120 Amperes (its value can be measured using special current clamps). In addition to the current component, after switching on the device, it is mandatory to control the temperature sensors installed in the area of the radiators.

At the final stage of putting the device into operation, it is necessary to check it for operability under load. To do this, a sufficiently “powerful” rheostat with an active resistance of about 0.5 Ohm should be connected to the welding wires.

Important! This adjusting device must be designed for currents of at least 60 Amperes, which are controlled by an ammeter built into the device.

If the rheostat selected for tuning does not provide the desired current value, its nominal resistance should be selected empirically.

Testing a semi-automatic machine in operation

After starting the self-assembled semiautomatic device, its display panel should display a current value corresponding to a working value of 120 amperes. At the same time, the readings of the sensors installed on the cooling radiators should be monitored. homemade product(the temperature in the zone of their action should not exceed 100 degrees).

You will also need to check the adjustment range of the output (load) current, which cannot be less than 20-160 amperes.

In conclusion, we note that a do-it-yourself semi-automatic machine in compliance with all the rules discussed in this review will be able to serve its owner for a long time. Its performance and reliability will largely depend on the quality of the components used and the reliability of their assembly.