A semi-automatic welding machine can be homemade, made from an inverter. Let’s say right away what to make semi-automatic welding from an inverter with your own hands is not easy, but not impossible. Anyone who is planning to make a semi-automatic machine with their own hands from an inverter should study the principle of its operation, watch, if necessary, a video or photo on this topic, and prepare the necessary components and equipment.

How to convert an inverter into a semi-automatic machine

To work you will need:

WITHsemi-automatic welding diagram

Particular attention is paid to redesigning the feeder, which feeds wire into the welding zone, which moves along flexible hose. To obtain a high-quality, neat weld, the wire feed speed through the flexible hose and the speed of its melting must be consistent.

When welding semi-automatically, wire of different diameters and from different materials, therefore it should be possible to regulate the speed of its supply. This is done by the feeding mechanism.

The most common wire diameters in our case: 0.8; 1; 1.2 and 1.6 mm. Before welding, the wire is wound onto reels, which are attachments secured with simple fasteners. The wire is fed automatically during the welding process, which significantly reduces the time of the technological operation and increases efficiency.

The main element of the electronic circuit of the control unit is a microcontroller responsible for stabilizing and regulating the welding current. The current parameters and the ability to regulate them depend on this element.

Remaking an inverter transformer

You can make a semi-automatic welding machine with your own hands by remaking the inverter transformer. To bring the characteristics of the inverter transformer in accordance with the required ones, it is wrapped with a copper strip wrapped with thermal paper. Ordinary thick wire is not used for these purposes, because it will get very hot.

The secondary winding is also redone. To do this you need:

• Wind a winding of three layers of sheet metal, each of which is insulated with fluoroplastic tape.
• The ends of the windings are soldered to each other to increase current conductivity.

IN design diagram The inverter used to switch into a semi-automatic device must be provided with a fan to cool the device.

Settings

When making a semi-automatic machine from an inverter, first de-energize the equipment. To prevent the device from overheating, place its input and output rectifiers, as well as power switches on radiators.

After completing the above procedures, connect the power section to the control unit and connect it to the power supply. When the power connection indicator lights up, connect an oscilloscope to the inverter outputs. Using an oscilloscope, look for electrical pulses at 40-50 kHz. There should be 1.5 µs between the formation of pulses, and this is regulated by changing the voltage supplied to the input.

Oscillogram of welding current and voltage: at reverse polarity - on the left, at normal polarity - on the right

Check that the pulses that are reflected on the oscilloscope screen are rectangular and their leading edge is no more than 500 ns. If the parameters being checked are as they should be, connect the inverter to the mains.

The current supplied from the output must be at least 120A. If this value is less, it is likely that a voltage not exceeding 100 V is flowing into the equipment wires. In this case, the equipment is tested by varying the current (plus the voltage on the capacitor is constantly monitored). The temperature inside the device is also constantly monitored.

After testing, check the device under load: connect a rheostat with a resistance of at least 0.5 Ohm to the welding wires. It must withstand a current of 60 A. The current supplied to the welding torch is controlled by an ammeter. If it does not correspond to the required value, the resistance value is selected empirically.

Usage

After starting the device, the inverter indicator should display a current value of 120 A. If the value is different, something was done incorrectly. Eights may appear on the indicator. Most often this occurs due to insufficient voltage in the welding wires. It is better to immediately determine the cause of this malfunction and eliminate it. If everything is correct, the indicator will correctly show the current strength, which is controlled by special buttons. The current adjustment interval provided by the inverters lies in the range of 20–160 A.

Checking for correct operation

For the semi-automatic to last long term, it is recommended to constantly monitor temperature regime inverter operation. For the purpose of control at the same time two buttons are pressed, and then the temperature of the hottest of the inverter radiators is displayed on the indicator. Normal operating temperature is no more than 75 ° C.

If there is more, in addition to the information that is displayed on the indicator, the inverter will make an intermittent sound, which should immediately alert you. In this case (or when the temperature sensor is shorted) electronic circuit will automatically reduce the operating current to 20A, and the sound signal will sound until the equipment returns to normal. An error code (Err), which is displayed on the inverter indicator, may also indicate a malfunction of the equipment.

When is a semi-automatic welding machine used?

Semiautomatic is recommended to be used when precise, neat connections of steel parts are needed. Using such equipment They weld thin metal, which is important, for example, when repairing car bodies. Qualified specialists or a training video will help you learn how to operate the device.

This article begins a new section “Tools and Devices”, and the article will be somewhat unusual, that is, it will not be about what and how to make, but on the contrary, what should not be done.

Thanks to the amazing labor productivity of the inhabitants of the Celestial Empire and the affordable cost, welding machines - “inverters” have firmly established themselves in the garages of many car owners. And for good reason: small size, light weight, wide and smooth current adjustment range, “soft” arc, low power consumption make this welding machine simply an invaluable assistant in many cases, but not always; a car “tin” is often too delicate for electrode welding. And then thoughts begin to arise in the inquisitive minds of car enthusiasts: what if we add a burner, draw wire and convert the “inverter” into a “semi-automatic” at low cost. I’ll say right away that this option will not work, and such an addition to a conventional welding machine on a transformer will also not work. Why? Read on.

Semi-automatic torch and welding wire

In order not to be unfounded: I have a DC welding machine on a transformer in the garage, also a few years ago I made my own semi-automatic machine (also a transformer one, which I use successfully), and this year I purchased an inverter welding machine (it’s a little hard to carry the transformer yourself). I decided to test this possibility “empirically”, especially since everything necessary is available and no costs are needed. I turned off the transformer in the “semi-automatic” machine, applied power from the “inverter”, tried... I’ll be honest - I tried it in different modes, adjusted the current, changed the wire feed speed, welded with and without gas... a normal seam never came out, it turned out, to put it mildly, “crap” "

Now a little theory. There is no way without this, but I will try to be as simple and brief as possible.

Types or types of welding.

MMA (ManualMetalArc). The most common type of welding is manual welding with flux-coated stick electrodes; by the way, this technology was developed by our compatriot N.G. Slavyanov.

TIG (TungstenInertGas). Welding with a non-consumable (tungsten or graphite) electrode in a protective inert gas environment (argon-arc welding). Invented by N.N. Benardos.

MIG (MechanicalInertGas). Mechanized supply of electrode material (semi-automatic or automatic) in an inert gas environment (argon, helium).

MAG (MechanicalactiveGas). Mechanized supply of electrode material (semi-automatic or automatic) in an active (carbon dioxide) gas environment. Which interests us most. By the way, alloyed wire (we use copper-bonded wire) was also invented by our compatriots K.V. Lyubavsky and N.M. Novozhilov.

Now let's figure out how power supplies differMMAAndMAG,and why they cannot be used one instead of the other.

First, let's look at the conditions for the existence of an electric arc used in welding. In the above graph it is noticeable that

that the current-voltage characteristic of the arc (volt-ampere characteristic) has three distinct sections:

• descending section– which corresponds to a low current density,
• horizontal section– with medium density current
• ascending section– which corresponds to a high current density.

So, at manual weldingMMA the arc burning process occurs in the middle section of the current-voltage characteristic, preferably in the first third, while the arc ignites easily, is kept stable, the seams are smooth and the metal does not spatter (at the same time, vibrations of the electrode (the welder’s hand) and changes in the length of the arc practically do not cause a change in the welding current If the current density increases and the burning point of the arc shifts to the ascending section, then the arc becomes unstable, “hard”, the metal splashes, the seams come out torn and uneven.

When welding semi-automaticMAG the arc point should be located at the beginning of the ascending section of the current-voltage characteristic, with high density current, and self-regulation of the welding process will occur.

Each type of welding must have a corresponding power source for the welding machine, be it an inverter or a transformer. For clarity, another graph,

which depicts external current-voltage characteristics of power supplies for welding machines.

Curve 1 corresponds to the steeply falling current-voltage characteristic of the power supply, which is almost ideal for manual welding on direct current MMA, curve 2 — flat-sloping current-voltage characteristic, curve 3 — rigid current-voltage characteristic, providing self-regulation when welding with thin wire MAG.

Conclusion: The DC manual welding power source is designed and manufactured with steeply dipping current-voltage characteristic , which absolutely not suitable for welding work wire electrode in semi-automatic mode . In relation to an inverter power supply, the control unit must be reworked and reconfigured, but if you are not very strong in electronics, then it is better not to mess with a well-established mechanism.

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

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 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

Convert the inverter into a semi-automatic welding machine for welding thin steel (low-alloy and corrosion-resistant) and aluminum alloys It’s not difficult to do it yourself. 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 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 the network is undergoing transformation alternating current to 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 feed speed welding wire were in a certain equilibrium. 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. Wire feed speed adjusts 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 provide quality work semi-automatic with small dimensions, it is best to use toroidal type transformers. They have the most high coefficient useful action.

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 desired and available necessary details it is quite possible to 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.

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.

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:

• A mechanism with the 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 specified 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 should work on the principle of current conversion high frequency. 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. Received 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;
• Feedback blocks responsible for 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 needs special system cooling. 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, the main cause is a broken regulator. When the first problems arise, the breakdown affects further work devices. Therefore, to avoid future renovation, you should spend as much time as possible on 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 throttle

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. Ready product must produce a minimum of 24 V at a current of 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. The use of ready-made structures is also permitted. You can make single-level, two-level and three-level products. For convenience, on upper level store tools and materials that will be needed for work. 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 welding inverter, you need 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 apparatus does not perceive the presence of dirt and dust well. 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 summer period 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 remake welding inverter semi-automatic almost free

Inverters are widely used by home and garage craftsmen. 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 - the current source high power, the semi-automatic machine 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 a computer system unit works well. 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 ready set. 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, check that there is no mutual contact 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.

Sufficient strength and (which is especially important!) electrical insulation from the metal case are ensured.

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.

Relay regular one will do automobile. Our power supply is 12 volts (computer power supply), so selecting components is convenient.

The valve itself is installed on free place in the case. 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).

At the moment, inverter MMA 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 aliexpress on already ready-made option and 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

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

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 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.

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 achieve the best welding results from the device.

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.

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.

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

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.

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