How to make a semi-automatic welding machine

How to make a semi-automatic welding machine with your own hands?

It is not very easy to assemble a semi-automatic welding machine from an inverter with your own hands, since this task will require certain knowledge in the field of electronics and the ability to solder various elements together. It is imperative to be well informed in terms of the key principles of operation of equipment that allows welding work to be carried out in a semi-automatic mode.

What components are needed?

To convert an inverter device from manual mode, you will need to use certain equipment. You also need to have a number of components on hand, without which it is not possible to fully complete the work:

• Since semi-automatic welding will be powered by an inverter, you will need to take an inverter capable of generating a welding current, the strength of which will reach at least 150 A;
• A special mechanism that ensures uniform and constant wire feed;
• The burner, which is a key working element;
• A hose of the required diameter through which the wire will be fed;
• Another hose through which a special protective gas will be supplied to the metal welding zone;
• A coil with welding wire wound on it, however, this part will have to be remade in a certain way;
• A special electronic unit, through which the operation of a homemade semi-automatic welding machine will be controlled.

The greatest attention should be paid to the feeder, which is responsible for feeding the wire into the welding zone. To obtain the most accurate seam without various defects on the outside, the wire feed speed in a homemade semi-automatic welding machine is selected so that the wire has time to completely melt and form a high-quality seam.

It is worth noting that in the process of semi-automatic welding, wire of different diameters and made of different materials can be used; accordingly, the melting rate will be different. To make working with semi-automatic welding machines as convenient as possible, the home-made design must have a mechanism for adjusting the speed of the device that will feed the wire.

How to properly convert a transformer from an inverter?

In order to ultimately obtain a high-quality semi-automatic welding machine, it is necessary to subject the inverter transformer to certain alterations. Doing this yourself is not too difficult, however, to do this you will have to follow a number of certain rules.

First of all, you need to make the winding of the transformer. To do this, you will need a copper strip and a thermal paper winding. You need to find exactly the strip; wire is not suitable for these purposes, since a semi-automatic welding machine assembled using this method with your own hands will become very hot.

The secondary winding also needs some modification. In the circuit of the semi-automatic welding machine, you need to add one more transformer winding, which includes three layers of tin.

This technological solution contributes to a significant increase in current conductivity. To know how to make a semi-automatic welding machine with your own hands, you need to remember the need to include a fan in the circuits of semi-automatic welding machines, which will be used to efficiently cool the entire structure, preventing it from overheating.

How to properly configure an inverter machine for semi-automatic welding work?

To make certain changes to the circuits of homemade semi-automatic welding machines, you must first completely de-energize this design. For additional protection against overheating, you need to install an input and output rectifier, as well as power switches, on the radiators.

When all these actions have been completed, the power part of the welding machine is connected to the control unit and try to connect it to the mains. First, the indicator should light up indicating that the product is connected.

Before testing the product in welding, you need to connect an oscilloscope to the outputs and use it to try to find electrical pulses, the frequency of which should be in the range from 40 to 50 kHz. A gap of 1.5 µs should be maintained between them - this effect can be achieved by changing the input voltage.

Once the optimal voltage has been found, you can try connecting the welding wire and welding the two workpieces.

How to adjust the feed mechanism?

To do this, you will need to take two bearings, the size of which must correspond to standard size 6202, you will also need an electric motor from car wipers, and the smaller its size, the better.

When selecting a welding machine and its compliance with the semi-automatic welding circuit, it is necessary to carefully check that it rotates strictly in one direction. In addition, you will need to take a roller with a diameter of exactly 25 mm. It is placed over the threads on the electric motor shaft. All non-standard structural elements are produced independently - this will make it much easier in the future to repair semi-automatic welding machines with your own hands.

The feed mechanism includes two plates on which bearings are mounted. Between them there is a roller with an electric motor connected to it. The plates are compressed by a spring; the same element of the homemade feed mechanism circuit allows the bearings to be pressed against the roller. The mechanism is assembled on a special textolite plate, its thickness is about 5 mm. This is done in such a way that the welding wire comes out of the mechanism in the area of ​​the connector.

This connector, in turn, will connect to the welding sleeve mounted on the front of the housing. A coil with wound wire is connected to the same plate. In order for the reel to hold well on the feed mechanism, a special shaft is made under it, which is attached perpendicular to the textolite plate. A thread should be cut from the edge of the shaft so that the coil fits onto it as tightly as possible.

The schematic diagram of a semi-automatic welding machine, manufactured independently, is practical, reliable and economical. It is worth noting that the design will probably not look very attractive, but in terms of its operational characteristics it will be practically no different from professional industrial equipment.

How is the inductor winding carried out?

In order for the inductor to work reliably and not overheat when electric current passes through it, you need to use an OSM-0.4 transformer, the power of which is 400 W. In addition, when making a high-quality structure, you will have to use an enamel wire, the diameter of which should be at least 1.5 mm, however, it is better to take with a small margin, for example, 1.8 mm.

Two layers of wire should be wound around the inductor, and they should be well insulated from each other. The wires in each of them are laid as tightly as possible - this is necessary to obtain a high-quality induction coil. At the next stage, you should use an aluminum tire measuring 2.8x4.65 mm.

It is wound in one layer, making 24 turns, and the remaining ends are made approximately 30 cm long. In the future, you will need to assemble the core; there should be a gap of approximately 1 mm between it and the coil. To make the connection as rigid as possible, small pieces of PCB will need to be laid between the core and the windings.

To power the control circuit, it is also necessary to use a transformer, and it is absolutely not necessary to assemble this design yourself, since you can purchase a finished product at a low price. The main criterion is that the design must produce 24 V at a current of about 6 A.

Summarize

If the entire structure is assembled correctly, it will be very convenient to use, and its service life will exceed even professional devices. However, if assembled incorrectly, the most vulnerable structural element will be the wire feed regulator, so from time to time these elements will require repair or maintenance work.

Otherwise, welding metal parts using a semi-automatic machine assembled by yourself is quite convenient and simple, since this technology is much simpler compared to traditional manual electric arc welding.

Source: https://electrod.biz/oborudovanie/poluavtomat/svarochnyiy-poluavtomat-svoimi-rukami.html

Making a semi-automatic welding machine with your own hands

Using a semi-automatic welding machine makes it easier to work with metals. This technique can easily join different alloys. You can make a semi-automatic welding machine with your own hands from an existing inverter, and a home-made unit will be distinguished by its versatility and functionality in use, allowing you to save on the purchase of industrial equipment.

Design Features

A design feature of a semi-automatic welding machine is the constant supply of molten wire into the welding zone, which is used instead of metal electrodes.

Wire feeding is carried out automatically, with the ability to change the speed of movement of flexible electrodes.

The welding wire used will ensure constant contact of the surfaces being connected; such material, in comparison with standard electrodes, has less resistance, which improves the quality of the connection.

Semi-automatic welding is distinguished by its versatility, which allows using this technology to weld metals of various characteristics, including stainless steel, non-ferrous alloys, aluminum and others. Mastering the correct semi-automatic welding technique is not difficult.

Homemade devices are easy to use, so they can be recommended to ordinary homeowners.

Depending on their type, semi-automatic machines may have an additional nozzle for supplying gas, and the metals are joined in a protective environment, which makes it possible to eliminate the subsequent formation of corrosion in the weld.

Welding inverters offered in stores today are distinguished by their versatility, and many of them have a two-in-one function. With low power and dimensions, a two-in-one inverter and semi-automatic welding machine can work with refractory metals and thick metal workpieces.

Advantages and disadvantages of homemade equipment

Many homeowners, who often have to perform welding work, decide to manufacture such equipment themselves. The advantages of homemade semi-automatic machines from an inverter include the following:

• Simplicity and reliability of technology.
• Functionality of the device.
• High power allows you to weld refractory metals.
• Affordable cost of the components used.
• Complete safety of working with the equipment.
• Ease of operation of the equipment.

Among the disadvantages of this technology and the equipment itself, one can note the high cost of semi-automatic machines, which, with characteristics similar to the inverter, can have a price two to three times higher. It is not surprising that many homeowners decide to make the equipment themselves, which allows them to significantly reduce costs without losing the quality of the device.

Source: https://pochini.guru/sovety-mastera/izgotovlenie-svarochnogo-poluavtomata

Do-it-yourself semi-automatic welding machine - diagrams and description

In this article we will tell you how to make a semi-automatic welding machine with your own hands? The main thing that is needed for this is enthusiasm. After reading the theoretical information, you can begin assembly. To begin with, I would like to clarify what is the difference between a semi-automatic welding machine and a machine that works with electrodes.

When manual welding is carried out, the load current must be constant, but in automatic welding the main thing is voltage stability. This is, in general terms. We will manufacture a universal device, i.e. automatic with arc welding (MAG/MMA).

Feed mechanism

Assembly should begin with the wire feed and tension mechanism. To assemble the mechanical part, you will have to use a pair of bearings (size 6202), an electric motor from car wipers (the smaller the motor, the better).

When choosing a motor, make sure that it rotates in one direction, and not “from side to side”. In addition, you will need to grind or find somewhere a roller with a diameter of 25 mm. This roller sits on top of the thread on the electric motor shaft. Each non-standard detail must be made by hand, fortunately, there is nothing complicated there.

The design of the feed mechanism consists of two plates on which the bearings are fixed, and a roller on the electric motor shaft, located in the middle. The plates are compressed and the bearings are pressed against the roller using a spring. From one bearing to the roller, a wire is drawn, threaded inside the “guides” on both sides of the rollers.

Installation is carried out on top of a textolite plate, the thickness of which is 5 mm. This is done so that the wire comes out where there will be a connector into which the welding sleeve attached to the front of the body is connected. We also install a reel on which the wire is wound on the PCB. We grind a shaft under the coil, which is installed at an angle of 90° to the plate, which has a thread on the edge to fix the latter.

The design of the semi-automatic do-it-yourself reference machine is simple and reliable, approximately the same as is used for industrial devices. The parts in the feed mechanism are designed for a regular coil, but welding will be carried out without gas; it’s good that welding wire is sold everywhere.

What should happen is shown at the top at the beginning of the article. Reinforcement of the computer case is carried out using two corners on those sides where the electronic part of the device is supposed to be installed. The rear wall of the case has a power supply and a device that regulates the frequency at which the electric motor rotates.

Semi-automatic wire feeding diagram

A transformer is quite suitable for these purposes. It is the simplest and most reliable method of powering an electric motor. The most optimal feed rate control circuit is a thyristor one. Below you can see the electrical circuit with which the feed motor is controlled.

Feeder PCB

This circuit does not have a smoothing capacitor; this is how the thyristor is controlled. The diode bridge can be anything, the main thing is that the current exceeds 10A. We use BTB16 with a flat case as a thyristor; it can be replaced with KU202 (any letter). The transformer, which contains a semi-automatic do-it-yourself welding machine, must have a power exceeding 100W.

Another option for wire feed speed controller

Source: http://sdelaj-sam.com/poluavtomat-svarochnyj-svoimi-rukami-shemy-i-opisanie/

Step-by-step instructions for making a semi-automatic welding machine with your own hands

An automatic welding machine is a special device designed for welding joints of metal products. The devices are manufactured with different parameters, but regardless of the type, the most important design element is the inverter mechanism.

For stable operation, it is required that the inverter has high quality, the required functionality, and is safe for the user.

Devices from well-known brands are expensive, while Chinese ones do not inspire confidence among consumers. Therefore, some welders prefer to make semi-automatic welding machines with their own hands using simple diagrams and manufacturing technology.

What will you need?

The homemade apparatus includes:

• a mechanism that controls the characteristics of the output current;
• power unit;
• burners;
• clamping devices;
• rubber sleeves;
• cart.

To assemble a semi-automatic welding device with your own hands you will need:

• device for additive wire;
• a flexible hose for supplying powder or gas under the required pressure to the welded joint area;
• coil;
• electronic unit for controlling the device.

Principle of operation

The semi-automatic welding production process consists of:

• moving and adjusting the burner;
• controlling the welding process.

The function of an inverter semiautomatic device is the transformation of alternating current received from the network into direct current . The length and quality of the arc depends on the voltage, and the rate of addition of the additive is determined by the welding current.

The operating principle of any self-made semi-automatic device is as follows:

• purge to remove blockages that impede a stable gas supply;
• turning on the power supply;
• additive supply;
• operation of the inverter at a given pace;
• covering the seam and welding the formed crater.

At the final stage, if necessary, manual cleaning of the joint or surfacing is performed , the seam is protected and the crater is sealed.

Created plan

Before producing a semi-automatic welding machine with your own hands, an action plan is drawn up at each stage of work. This will increase the speed of installation and determine the required devices and products.

First you need to decide on the circuit diagram of the semiautomatic device.

Next, you need to think about what device or device to use as a housing for compact installation of electronic components and mechanisms.

Then you need to analyze the dimensions of the parts required for assembly and consider their placement inside the case. For example, if you have time, you can make three-dimensional prototypes of parts and place them in a space of suitable volume according to the accepted scheme of a semi-automatic welding machine.

Preparing the transformer

The transformer consists of a pair of coils with a winding of insulated wire, one winding is primary, the other is secondary.

To remake an inverter device, only the secondary coil is changed . It needs to be redone to reduce the voltage and increase the current. To do this, the existing wrap is removed and a new one is wound from the insulated cable.

The number and thickness of turns can be determined using specialized online services.

Upon completion of laying the wires, the windings are covered with insulating material.

Source: https://svarka.guru/oborudovanie/vidy-apparatov/poshagovaya-instrukciya-po-izgotovleniju-poluavtomata-svoimi-rukami.html

Do-it-yourself semi-automatic inverter

A semi-automatic welding device for household needs can be purchased ready-to-use or completely assembled with your own hands. A homemade semi-automatic machine will cost the performer much less, but its assembly will require certain skills in working with electrical equipment. The appearance of such a welded device is shown in the figure below.

Appearance of a homemade semi-automatic machine

We recommend that everyone who wants to make a semi-automatic machine from an inverter with their own hands first familiarize themselves with the structure of this unit and the operating features of the modules included in it.

What is needed to remake an inverter

Before making a semi-automatic welding machine with your own hands, you will need to prepare the following functional modules and spare parts that provide the required complete set of prefabricated equipment:

• An old inverter unit designed for a welding current of about 150 Amps;
• Another working unit of the future semi-automatic device is the so-called “burner”;
• A special feeding mechanism, with the help of which it will be possible to organize the delivery of welding wire to the place of work;
• Hoses that supply wire and shielding gas to a homemade welding unit (more precisely, to the area where work operations are performed);
• A coil redesigned for new needs with a special wire placed on it;
• A separate electronic module that controls the functioning of the entire home-made device (including the converter transformer).

The complete set of components and modules required for the semi-automatic machine can be found in the figure below.

Unit design

Do-it-yourself spotter from a welding machine

Let's look at the most important parts of units made by hand from an inverter in more detail.

Consumable supply unit and burner

When equipping with spare parts, special attention should be paid to a thorough modification of the wire feeder, which will have to move inside the flexible hose.

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

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

When setting up a semi-automatic circuit, consumable wire with sections of 0.8, 1.0, 1.2 and 1.6 mm is most often used. Immediately before starting work, it is wound on pre-prepared reels, which are fixed to the elements of the unit using simple 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 torch used in a semi-automatic machine can be taken entirely from a non-working welding unit of the same type or made independently at home. Let’s immediately make a reservation 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.

Electronic circuit (control unit)

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

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

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

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

Simplified electronic module diagram

Transformer

Another critical component of a semi-automatic machine, made with your own hands from an old welding device, is a transformer, which can be taken from the same inverter (subject to minor modifications).

To ensure the required characteristics of the inverter transformer, which are completely 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-section copper wire, since they will become very hot under high current loads.

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

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

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

Assembly of the unit

DIY wind generator from a car generator

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

Power switches on radiators

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

After completing all of the above procedures, you should begin mating the power module with the electronic control unit, after which you can try to connect it to the network and check its operation.

Inverter setup

Do-it-yourself gasoline generator

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

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

Diagrams of voltage at the output of the converter

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 amount of control potential supplied to the input of the converter is usually measured using an electronic voltmeter.

In the process of setting up the conversion system, it is also necessary to monitor the shape of the pulses observed at the output, which should approach rectangular with rises lasting no more than 500 ns. If all the above parameters 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 a working unit should have a value of about 120 Amperes (its value can be measured using special current clamps). In addition to the current component, after putting the device into operation, it is necessary to monitor the temperature sensors installed in the area where the radiators are located.

At the final stage of putting the device into operation, it is necessary to check its functionality 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 using an ammeter built into the device.

If the rheostat selected for adjustment does not provide the required current value, its nominal resistance should be selected experimentally.

Testing a semi-automatic device in operation

After starting the self-assembled semi-automatic device, its indicator panel should display a current value corresponding to the operating value of 120 Amperes. At the same time, you should check the readings of the sensors installed on the cooling radiators of the homemade product (the temperature in their area of ​​​​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 semi-automatic machine, made by hand in compliance with all the rules discussed in this review, will be able to serve its owner for quite a long time. Its performance and reliability will largely depend on the quality of the components used and the reliability of their assembly.

Source: https://amperof.ru/elektropribory/poluavtomat-iz-invertora.html

Do-it-yourself semi-automatic welding machine: diagram, video

The cost of units for semi-automatic welding is currently quite high. Not every private master, owner of a car or a private house will be able to afford to purchase it.

But most home craftsmen can assemble such a semi-automatic welding machine with their own hands from readily available and relatively inexpensive components.

If you follow the recommendations below, you can achieve an excellent result - assemble a homemade welding machine, suitable for almost all household needs.

Today on the Internet there are several variations of semi-automatic welding circuits, differing slightly. There are many videos and drawings that allow you to assemble a semi-automatic device based on a conventional inverter for household use.

As a basis for the manufacture of a semi-automatic welder, any inexpensive factory model of a welding inverter capable of producing direct current with a value of 150A or more is suitable.

In addition, to assemble a workable device circuit, you will need the following equipment, components and materials:

• feeding mechanism for semi-automatic machine;
• an element characteristic of the design of a semi-automatic unit - a gas pistol-burner;
• a cylinder with an inert gas (carbon dioxide);
• modified coil with consumable material - wire;
• two sleeves - for supplying welding wire and shielding gas to the torch;
• electronic control module.

Feeder

According to information from craftsmen, one of the most difficult tasks when independently manufacturing a welding machine of a semi-automatic operating principle is creating a reliable and efficient wire feed mechanism.

In the general case, it is a coil connected to the shaft of a low-power electric drive via a pressure roller device. It may be sufficient to use an electric motor installed on the windshield wipers of a car.

When choosing a drive, preference should be given to single-rotation motors.

All elements of the feeding mechanism are mounted on a thick-walled textolite plate (at least 8-10 mm thick). The coil is fixed by means of one or two ball bearings on a shaft of the appropriate diameter, fixed in the housing. A roller is mounted on the electric motor shaft, which is fixed on both sides by ball bearings. At the output of the assembly, it is necessary to install a guide with a hole diameter slightly larger than the size of the wire used.

The functioning of the wire feed regulator is as follows:

The wire from the loosely attached spool is pulled through the guide element and pressed with optimal force by one of the rollers. The force must be such that it ensures the pulling of the welding wire without slipping, but not excessive, which can lead to an increase in the mechanical load on the electric drive, which can easily damage it. For this effect, use a spring on an adjustable threaded connection.

The wire feed control circuit is best implemented using a classic thyristor unit with a diode bridge designed for a current exceeding 10A. Under other conditions, this unit is capable of feeding welding wire of most sizes used in household welding (from 0.8 to 1.6 mm), and the drawing speed can be adjusted independently (depending on the diameter of the consumable).

Modification of the factory inverter

Remaking the circuit of a semi-automatic welding machine from an inverter-type unit involves modifying its transformer. To do this, it is necessary to wrap its primary coil with a strip of thin copper in a thermally insulating winding. Ordinary copper wire cannot be used for this purpose due to high temperatures that can damage the PVC insulation.

The coil of the secondary circuit of the transformer should also be adapted for new tasks by winding three layers of the same wire over the existing winding, insulated with fluoroplastic tape. To increase the conductivity of currents, it is necessary to solder together the standard terminals of the coil with additional windings.

Burner

You can make this element for semi-automatic welding yourself. But it is better to use ready-made factory solutions from the manufacturers of this equipment by installing a standard torch equipped with welding hoses (for inert gas and wire) into a homemade welding machine, since this unit is one of the most responsible for the quality of the welding processes carried out.

Balloon

Of course, it is better to use a standard inert gas cylinder, since only such a product can meet all safety requirements. However, such containers are overly bulky and quite expensive, so many home craftsmen have found a solution: for infrequent use of a semi-automatic welder, a fire extinguisher connected to the gearbox using a special threaded adapter is used as a cylinder (for carbon dioxide only).

How to set up a homemade semi-automatic welding unit

To ensure safety and full functionality, the semi-automatic welding circuit must include cooling means - passive (radiators) installed in the highest heating zones (on power switches and rectifiers) and active - one or two fans mounted in the device body.

In case of overheating during operation, you should install a temperature sensor in the area of ​​the hottest radiator, configured to turn off the power when the temperature reaches 75 degrees.

And for ease of use, you can install an indicator light in the power circuit, signaling the presence of incoming voltage.

A semi-automatic welding machine made by yourself must be subjected to diagnostics. For this purpose, two types of electrical measuring instruments are used.

Using an oscilloscope and a multimeter, the shape, amplitude of the pulses, their repetition rate and some other characteristics are monitored. Ideally, devices should display the following values: frequency - within 4050 kHz (with a time interpulse distance of 1.

5 μs), current value - not lower than 120A (better - 150A). The signal shown on the oscilloscope screen should be as close to a square wave as possible.

When turned on in operating mode (under a load with calibrated parameters - an active resistance of 0.5 Ohm), a current of at least 60A must be provided, which can be checked with a multimeter. If this value is less, in this case it is necessary to independently select the resistance for normal operation of the unit experimentally.

As can be seen from the above material, independently converting an inverter welder into a semi-automatic one is a task that is feasible for any person with a certain level of knowledge and experience in the field of mechanics and electrical engineering. Having the necessary components, materials and, most importantly, desire, you can simply and quickly assemble a machine for semi-automatic welding at home.

Source: https://svarkalegko.com/oborudovanie/svarochnyj-poluavtomat-svoimi-rukami.html

Do-it-yourself semi-automatic welding machine for household use: inverter circuit, preparation, assembly - VashElektrik

The semiautomatic welding machine is a very useful and multifunctional device. With its help, you can make a variety of metal structures and weld a car part without resorting to outside help. Of course, you can purchase a ready-made tool, but if you have basic knowledge of electronics, you can make a semi-automatic welding machine from an inverter with your own hands.

The semi-automatic welding machine is a very useful and multifunctional device

The circuit of a semi-automatic welding machine is not particularly complicated.

But in order to do it yourself, you need to become familiar with the stages of work in detail, look at what the circuit diagram looks like, study the relevant videos and photographs, and also prepare all the components and auxiliary tools necessary for assembling the semi-automatic welding machine with your own hands.

Preparing for work

How to make a semi-automatic welding machine with your own hands? Remaking the device begins with planning the stages of work. First of all, you need to think carefully about the placement of the feed mechanisms and wire reel. The future housing should be quite spacious, lightweight, easy to clean, and also open and close well.

Experienced welders believe that the best option is an old computer system unit.

It has a compact and pleasant appearance, quite lightweight since it is made of thin material (another plus is the ease of making the necessary cutouts), and the built-in power supply has a voltage of 12 Volts, which is ideal for powering the welding wire feed drive and gas valve. In the absence of a system unit, any metal or plastic box of suitable size will do.

Experienced welders believe that the best option is an old computer system unit

As for the electrode wire, it is best to use a five-kilogram reel. With an internal diameter of 50 mm, it fits perfectly into the PVC sewer pipe, which can be adapted as a rotation axis.

Next, the dimensions of the parts for the semi-automatic machine are analyzed and the location in the body is considered. For clarity, it is best to make mock-ups of elements from cardboard and check their placement. After this, you can begin to make a machine for semi-automatic welding.

Preparing the inverter

The transformer consists of two coils of insulated copper wire. One of the windings is primary, the other is secondary.

To convert the welding inverter into a semi-automatic machine, we need just a secondary one. It is altered to increase the current and reduce the voltage.

To do this, remove the old winding of the transformer and, using a wire coated with a layer of enamel, wind a new one.

All actions should be performed very carefully, trying not to damage the primary winding and laying the turns close to each other. The thickness of the wire and the number of turns are calculated using special online programs. After the winding is completed, it is coated with a current-insulating substance.

Wire feed mechanism

A homemade welding machine will work efficiently only when the wire feed is continuous and uniform. This can be achieved in three ways:

1. Buying a new ready-made mechanism is quite expensive, but the fastest option.
2. Purchase feed reels only.
3. Make the device yourself. For this you will need:

• a pair of bearings (one of them must be pressure bearing and, accordingly, adjustable);
• tension spring;
• guide roller;
• motor for feeding electrode wire (you can use a motor from windshield wipers);
• metal plate on which the device will be attached.

Assembly steps:

1. We make holes on the plate for attaching the bearings and the motor shaft.
2. We fix the motor on the back side of the plate.
3. We put the guide roller on the shaft.
4. We fix our bearings at the top and bottom.

DIY semi-automatic welding machine

We place the resulting part in the housing in such a way that the rollers are placed along the same guide with the burner connector - then the wire will not break. To align the wire, it is advisable to install a rigid tube in front of the rollers.

Cooling system

Since a homemade semi-automatic welding machine is prone to overheating, it is necessary to provide a high-quality cooling system.

The easiest way to do this is to install fans (you can use coolers from old computers and other office equipment) on the sides of the case. It is advisable that they be located opposite the transformer device.

The devices are fixed in such a way that they work in exhaust mode.

Electrical component

To operate a semi-automatic machine converted from a welding inverter, it is necessary to ensure the correct electrical circuit. For this you will need:

• a pair of automotive relays;
• PWM controller for the motor;
• diode;
• capacitor with transistor;
• wires;
• automobile idle speed solenoid valve (VAZ models are considered the most suitable).

To operate a semi-automatic machine converted from a welding inverter, it is necessary to ensure the correct electrical circuit

The electrical control circuit of the semi-automatic welding machine is carried out in the following sequence:

1. When the torch button is pressed, both relays are activated.
2. The first relay activates the gas supply valve.
3. The second relay operates in parallel with the capacitor and starts the wire feed with a delay.
4. Using an additional button, the wire is pulled, bypassing the relay that provides the gas supply.
5. A diode is connected to the solenoid valve - this is necessary to remove self-induction.
6. In order for the burner to be connected to the power cable from the inverter, a quick-release connector is installed next to the Euro connector and connected to the burner.

Semi-automatic control

In order to control the device, a special board is required. The control circuit must include the following components:

• master generator with galvanic isolation transformer;
• control relay unit;
• feedback blocks designed to be responsible for the mains voltage and current supply to the device;
• thermal protection block;
• antistick block.

Operating rules

A homemade inverter semi-automatic device requires a slightly different attitude than ready-made devices. It is important to know that exposure to dust and dirt is detrimental to such devices, therefore, depending on the frequency of operation, the structure must be cleaned every 3-6 months.

In addition, it is unacceptable to use semi-automatic welding machines made by yourself at temperatures below 15°C. They are also not suitable for professional activities - in this case, the best option would be to purchase a factory-made product.

But for use at home, such a unit will be an excellent help.

Source: https://agk-sport.ru/provoda/svarochnyj-poluavtomat-bytovogo-naznacheniya-svoimi-rukami-shema-invertora-podgotovka-sborka.html

Homemade semi-automatic welding machine

The capabilities of a semi-automatic welding machine are significantly higher than those of a machine designed for manual arc welding. A semi-automatic machine can weld much thinner metal.

The use of a special welding wire allows you to work with non-ferrous metals, and the use of shielding gas provides a weld of higher quality. Considering these circumstances, the desire to add such a device to your home workshop is understandable.

General information

If you can’t buy a semi-automatic welding machine, you can try to assemble it yourself. It must be said right away that this task is not the easiest, and only those who have certain skills in working with electrical devices, have already repaired something, and understand circuits, can assemble a homemade semi-automatic welding machine. For those who decide to do this, we can recommend several possible assembly options.

Before planning work on creating a semi-automatic welding machine, you should study the principles of semi-automatic welding, as well as the design and operation of the device intended for this.

Semi-automatic welding machines are devices that carry out direct current electric arc welding using a special welding wire as an electrode in a shielding gas environment.

The wire is wound on a rotating spool and is automatically fed to the welding site, passing through a feed mechanism. The circuit of a semi-automatic welding machine can contain both an inverter and a transformer current source.

The welder lights the arc with his own hands and makes the seam, which is why the work is called semi-automatic. An analogue of the electrode holder in a semi-automatic welding machine is a torch that has a pistol grip with a button for turning on the wire feed.

The wire is fed through a thin channel passing inside the rubberized sleeve connecting the semiautomatic device to the burner. The channel for supplying gas during welding is located in the same sleeve and ends with a nozzle at the end of the torch.

Before lighting the arc, by turning on the wire feed, you need to ensure that it extends beyond the edge of the torch by 10 - 15 mm.

Then the gas supply is turned on and the welding process begins. The wire and gas feed speed is adjusted by hand and by rotating the heads located on the front panel of the semi-automatic welding machine.

From a welding transformer

If you have an old welding transformer at your disposal, it can serve as the basis for assembling a semi-automatic machine with your own hands.

If the old device has a rectifier and successfully cooks with direct current, nothing else needs to be done in this part. If it is just a transformer for AC welding, it should be modified.

Diode bridge

In order to obtain a source of direct current for welding, the transformer must be equipped with a diode bridge and a filter. The diode assembly rectifies the secondary voltage, the filter smoothes out ripples, maintaining stable arc burning.

The rectified voltage of a single-phase transformer has the form of a sinusoid, the lower half-waves of which are reflected symmetrically to the abscissa axis and moved to the upper quadrants of the coordinate system.

Essentially, this is a voltage pulsating at a frequency of 100 hertz, reaching zero twice per period. Using such a voltage for welding as a constant voltage leads to an unstable arc. To eliminate this phenomenon, a filter is required to smooth out voltage dips.

Filter

The filter consists of a choke connected in series to the welding circuit and a capacitor connected in parallel. This combination of inductance and capacitance is called an L-shaped filter, because in the diagram, the elements connected in this way form the letter L.

The capacitor for the future semiautomatic device needs an electrolytic, polar, capacity of 10,000 microfarads, the more the better. The capacitor voltage must be at least 100 volts to have a good margin. You can solder several capacitors in parallel, and the capacitance is summed up.

Throttle

To wind the inductor with your own hands, you need to find an old transformer of suitable dimensions. A power transformer from old tube color TVs with a power of at least 250 watts is well suited for this purpose.

The transformer has two coils on an oval closed core consisting of two halves. The transformer is disassembled, the coils are removed, and the old wire is removed from them.

For winding, a suitable flat copper busbar is selected. On each coil, instead of the removed wire, two layers of turns of a copper bus are wound by hand. The coil should have 15 - 20 turns.

After this, the steel core is assembled, the coils are put in place, and a 1.5 mm thick textolite gasket is inserted between the halves of the core. The coils are connected in series.

Broach

You can build a wire drawing mechanism for a semi-automatic machine with your own hands, using small bearings and an electric motor from car wipers.

But it is better to buy a ready-made one; it is sold as a spare part for semi-automatic welding machines. You will also have to buy a torch and a hose through which wire and gas will be supplied.

From an inverter for manual welding

If the workshop has a welding inverter for manual welding, the problem with the power source for the semi-automatic machine can be considered solved. Based on a manual welding machine, you can make a semi-automatic inverter with your own hands.

In order not to disassemble a working inverter converter, you can proceed as follows. All additional components necessary for the operation of the semi-automatic welding machine can be located in a separate housing.

Case manufacturing

The task is to find or manufacture a suitable housing in which a reel of welding wire will be installed, freely rotating on a drum, and a wire drawing mechanism. On the front panel of this housing there will be a socket for connecting a hose with a torch and a wire feed speed regulator.

The current can be adjusted on the inverter; the positive terminal can also be connected to the workpiece directly from the inverter.

The negative terminal of the inverter must be inserted into a new housing and connected to the sleeve terminal. The welding wire must be connected to this potential.

Also inside the new housing, provision should be made for installing a hose connecting the shielding gas cylinder and the torch sleeve. To provide controlled gas supply, you can install a valve from a car windshield wiper.

Providing power to the broach and valve

Since the electric motor of the wire drawing mechanism and the valve that shuts off the gas are powered by a constant voltage of 12 volts, you will have to install a small transformer with a rectifier to provide this power.

To switch the motor and valve, it is better to install intermediate automotive relays at 12 volts. The wire drawing is turned on using a key on the torch, held by hand, to open and close the gas supply valve; a toggle switch is installed on the front panel.

This arrangement will allow you to use the inverter both for manual welding and as a power source for a semi-automatic welding machine. The costs of manufacturing a homemade semi-automatic device are low, but the benefits from it will be tangible.

Source: https://svaring.com/welding/apparaty/svarochnyj-poluavtomat-svoimi-rukami

How to make a semi-automatic machine from an inverter with your own hands: conversion algorithm, connection diagram - TechnoExpert

A semi-automatic welding machine is a functional device that can be purchased ready-made or made from an inverter with your own hands.

It should be noted that making a semi-automatic device from an inverter device is not an easy task, but it can be solved if desired.

Those who set such a goal should thoroughly study the operating principle of a semi-automatic device, watch thematic photos and videos, and prepare all the necessary equipment and components.

Scheme of semi-automatic welding in a shielding gas environment

What is needed to convert an inverter into a semi-automatic machine?

To convert an inverter into a functional semi-automatic welding machine, you must find the following equipment and additional components:

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

Electrical circuit of a homemade semi-automatic machine

Special attention should be devoted to redesigning the feeder, through which welding wire is supplied to the welding zone, moving along a flexible hose. In order for the weld to be high-quality, reliable and accurate, the wire feed speed through the flexible hose must correspond to the speed of its melting.

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

Appearance of a homemade semi-automatic welder

Internal layout Wire reel Wire feeder (type 1)
Wire feeder (type 2) Attaching the welding hose to the feeder Design of a homemade torch

The most common wire diameters used in semi-automatic welding are 0.8; 1; 1.2 and 1.6 mm.

Before welding, the wire is wound onto special reels, which are attachments of semi-automatic devices, fixed to them using simple structural elements.

During the welding process, the wire is fed automatically, which significantly reduces the time spent on such a technological operation, simplifies it and makes it more efficient.

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

How to convert an inverter transformer

In order for the inverter to be used for a homemade semi-automatic device, its transformer must be subjected to some modifications. It’s not difficult to do this kind of alteration yourself, you just need to follow certain rules.

To bring the characteristics of the inverter transformer into line with those required for a semi-automatic device, you should wrap it with a copper strip on which a thermal paper winding is applied. It must be borne in mind that for these purposes you cannot use ordinary thick wire, which will become very hot.

Converted inverter transformer

The secondary winding of the inverter transformer also needs to be redone. To do this, you need to do the following: wind a winding consisting of three layers of sheet metal, each of which must be insulated with fluoroplastic tape; Solder the ends of the existing winding and the one you made yourself together, which will increase the conductivity of currents.

The design of the inverter used to include it in a semi-automatic welding machine must necessarily provide for the presence of a fan, which is necessary for effective cooling of the device.

Setting up an inverter used for semi-automatic welding

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

Power diodes on additional radiators

After all of the above procedures have been completed, you can connect the power part of the device to its control unit and connect it to the electrical network.

When the network connection indicator lights up, an oscilloscope should be connected to the inverter outputs. Using this device, you need to find electrical pulses with a frequency of 40–50 kHz.

The time between the formation of such pulses should be 1.5 μs, which is regulated by changing the voltage value supplied to the device input.

Oscillogram of welding voltage and current: on the left with reverse polarity, on the right with direct polarity

It is also necessary to check that the pulses reflected on the oscilloscope screen are rectangular in shape, and their front is no more than 500 ns. If all the checked parameters correspond to the required values, then you can connect the inverter to the electrical network. The current coming from the output of the semi-automatic device must be at least 120 A.

If the current value is less, this may mean that a voltage is supplied to the equipment wires, the value of which does not exceed 100 V. If such a situation arises, you must do the following: test the equipment by changing the current strength (in this case, you must constantly monitor the voltage on the capacitor).

In addition, the temperature inside the device should be constantly monitored.

After the semi-automatic machine has been tested, it is necessary to test it under load. To make such a check, a rheostat is connected to the welding wires, the resistance of which is at least 0.5 Ohm. Such a rheostat must withstand a current of 60 A.

The current strength that flows to the welding torch in such a situation is controlled using an ammeter.

If the current strength when using a load rheostat does not meet the required parameters, then the resistance value of this device is selected empirically.

How to use a welding inverter

After starting the semi-automatic device that you assembled with your own hands, the inverter indicator should display a current value of 120 A. If everything is done correctly, then this will happen.

However, the inverter indicator may display a figure of eight. The reason for this is most often insufficient voltage in the welding wires.

It is better to immediately find the cause of such a malfunction and promptly eliminate it.

If everything is done correctly, the indicator will correctly show the strength of the welding current, which is adjusted using special buttons. The operating current adjustment interval provided by welding inverters is in the range of 20–160 A.

Approximate modes of semi-automatic welding of butt seams

How to monitor the correct operation of equipment

In order for the semi-automatic welding machine that you assembled with your own hands to serve you for a long time, it is better to constantly monitor the temperature conditions of the inverter.

To carry out such control, you need to press two buttons simultaneously, after which the temperature of the hottest inverter radiator will be displayed on the indicator.

The normal operating temperature is considered to be one whose value does not exceed 75 degrees Celsius.

If this value is exceeded, then, in addition to the information displayed on the indicator, the inverter will begin to emit an intermittent sound signal, which should be noted immediately.

In this case (as well as if the temperature sensor breaks or shorts), the electronic circuit of the device will automatically reduce the operating current to 20A, and a sound signal will be emitted until the equipment returns to normal.

In addition, a malfunction of self-made equipment may be indicated by an error code (Err) displayed on the inverter indicator.

Setting the welding mode on the Resanta inverter

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

Practice shows that it is better to use a semi-automatic machine in cases where it is necessary to obtain precise and accurate connections of parts made of steel. With the help of such equipment, which, if desired, can be made by hand, welded joints of thin metal are made, which is very important when repairing the body of a vehicle.

Source: https://lobster-farm.ru/obsluzhivanie/kak-sdelat-poluavtomat-iz-invertora-svoimi-rukami-algoritm-peredelki-shema-podklyucheniya.html

Do-it-yourself semi-automatic welding machine from Sanych, diagram

A semi-automatic welding machine can be homemade, made from an inverter. Let’s say right away that making a semi-automatic welding machine 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:

• An inverter machine that can generate a welding current of 150 A.
• Feeding mechanism for a semi-automatic machine (welding wire).
• Burner.
• The hose through which the welding wire passes.
• Hose for supplying shielding gas to the welding zone.
• Reel of welding wire (will require some modifications).
• Electronic control unit.

Semi-automatic welding circuit diagram

Particular attention is paid to redesigning the feeder, which feeds wire into the welding zone, which moves along a 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 semi-automatic welding, wire of different diameters and from different materials is used, so it should be possible to regulate the speed of its feed. 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 being 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.

The design of the inverter used for inclusion in a semi-automatic device must include 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

In order for the semi-automatic device to serve for a long time, it is recommended to constantly monitor the temperature conditions of the inverter. For control purposes, two buttons are pressed simultaneously, and then the temperature of the hottest inverter radiator 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), the 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, thin metal is welded, which is important, for example, when repairing car bodies. Qualified specialists or a training video will help you learn how to operate the device.

In the workshop and at home, a craftsman will need a semi-automatic welding machine to repair a fence or canopy, a car body, or build a greenhouse.

What is better: buying new equipment or assembling a semi-automatic welding machine with your own hands depends on personal capabilities. But there is such a possibility. You can use a regular inverter or welding transformer as a power source and purchase some additional parts.

A homemade semi-automatic machine works according to the same scheme as a regular welder, with the only difference being that the electrodes are replaced by filler wire. It is supplied to the working area automatically, using a special mechanism. Thanks to the continuous gradual feeding of the wire, a zone of molten metal is formed for the rapid connection of elements.

The electrical circuit may have an inverter or transformer as a current source. The welder lights an arc on a pistol-type torch and regulates the supply of consumables through a rubber-coated hose. Gas simultaneously flows through this channel.

The semi-automatic machine attracts with its simple operating principle and performance. When welding, the seam lies smoothly and evenly and has high strength. The structure assembled at home will be able to weld steel, stainless steel and non-ferrous metals.

Semi-automatic welding from an inverter

To convert an inverter into a semi-automatic welding machine, you will need three main modules. Electric, providing current from the inverter and welding mode, a mechanism for supplying wire and a torch with a nozzle.

The burner creates a gaseous environment in the form of a cloud of protective inert gas that prevents oxidation of the molten metal. For this, a carbon dioxide cylinder is used, which is connected to the device using a hose and an inlet fitting.

If you use filler material with a special coating that forms a protective environment, you can do without a cylinder. This method is common among craftsmen.

Source: https://crast.ru/instrumenty/svarochnyj-poluavtomat-svoimi-rukami-ot-sanycha