Technical data of our semi-automatic welding machine:
Supply voltage: 220 V
Power consumption: no more than 3 kVA
Operating mode: intermittent
Operating voltage regulation: stepwise from 19 V to 26 V
Welding wire feed speed: 0-7 m/min
Wire diameter: 0.8mm
Welding current value: PV 40% - 160 A, PV 100% - 80 A
Welding current control limit: 30 A - 160 A
A total of six such devices have been made since 2003. The device shown in the photo below has been in service since 2003 in a car service center and has never been repaired.
Appearance of semi-automatic welding machine
At all
Front view
Back view
Left view
The welding wire used is standard
5kg coil of wire with a diameter of 0.8mm
Welding torch 180 A with Euro connector
was purchased at a welding equipment store.
Welder diagram and details
Due to the fact that the semi-automatic circuit was analyzed from such devices as PDG-125, PDG-160, PDG-201 and MIG-180, the circuit diagram differs from the circuit board, since the circuit emerged on the fly during the assembly process. Therefore, it is better to stick to the wiring diagram. On printed circuit board all points and details are marked (open in Sprint and hover your mouse).
Installation view
Control board
A single-phase 16A type AE circuit breaker is used as a power and protection switch. SA1 - welding mode switch type PKU-3-12-2037 for 5 positions.
Resistors R3, R4 are PEV-25, but they don’t have to be installed (I don’t have them). They are intended for fast discharge choke capacitors.
Now for capacitor C7. Paired with a choke, it ensures combustion stabilization and arc maintenance. Its minimum capacity should be at least 20,000 microfarads, optimal 30,000 microfarads. Several types of capacitors with smaller dimensions and higher capacity were tried, for example CapXon, Misuda, but they did not prove to be reliable and burned out.
As a result, Soviet capacitors were used, which still work to this day, K50-18 at 10,000 uF x 50V, three in parallel. 
Power thyristors for 200A are taken with a good margin. You can put it at 160 A, but they will work at the limit, they will require the use good radiators and fans. The used B200s stand on a small aluminum plate.
Relay K1 type RP21 for 24V, variable resistor R10 wirewound type PPB.
When you press the SB1 button on the burner, voltage is supplied to the control circuit. Relay K1 is triggered, thereby supplying voltage to the solenoid valve EM1 for supplying acid, and K1-2 - for the power supply circuit of the wire drawing motor, and K1-3 - for opening the power thyristors.
Switch SA1 sets the operating voltage in the range from 19 to 26 Volts (taking into account the addition of 3 turns per arm up to 30 Volts). Resistor R10 regulates the supply of welding wire and changes the welding current from 30A to 160A.
When setting up, resistor R12 is selected in such a way that when R10 is turned to minimum speed, the engine still continues to rotate and does not stand still.
When you release the SB1 button on the torch, the relay releases, the motor stops and the thyristors close, the solenoid valve, due to the charge of capacitor C2, still remains open, supplying acid to the welding zone.
When the thyristors are closed, the arc voltage disappears, but due to the inductor and capacitors C7, the voltage is removed smoothly, preventing the welding wire from sticking in the welding zone.
Winding up a welding transformer
We take the OSM-1 transformer (1 kW), disassemble it, put the iron aside, having previously marked it. We make a new coil frame from PCB 2 mm thick (the original frame is too weak). Cheek size 147×106mm. Size of other parts: 2 pcs. 130×70mm and 2 pcs. 87x89mm. We cut out a window measuring 87x51.5 mm in the cheeks.
The coil frame is ready.
We are looking for a winding wire with a diameter of 1.8 mm, preferably in reinforced fiberglass insulation. I took such a wire from the stator coils of a diesel generator). You can also use ordinary enamel wire such as PETV, PEV, etc.
Fiberglass - in my opinion, the most better insulation it turns out
We begin winding - the primary. The primary contains 164 + 15 + 15 + 15 + 15 turns. Between the layers we make insulation from thin fiberglass. Lay the wire as tightly as possible, otherwise it won’t fit, but I usually didn’t have any problems with this. I took fiberglass from the remains of the same diesel generator. That's it, the primary is ready.
We continue to wind - the secondary. We take an aluminum busbar in glass insulation measuring 2.8x4.75 mm (can be purchased from wrappers). You need about 8 m, but it is better to have a small margin. We begin to wind, laying it as tightly as possible, we wind 19 turns, then we make a loop for the M6 bolt, and again 19 turns. We make the beginnings and ends 30 cm each, for further installation.
Here is a small digression, personally, for me to weld large parts at such a voltage, the current was not enough; during operation, I rewound the secondary winding, adding 3 turns per arm, in total I got 22+22.
The winding fits snugly, so if you wind it carefully, everything should work out.
If you use an enamel wire as a primary material, then you must impregnate it with varnish; I kept the coil in the varnish for 6 hours.
We assemble the transformer, plug it into a socket and measure the current idle move about 0.5 A, voltage on the secondary is from 19 to 26 Volts. If everything is so, then the transformer can be put aside; we no longer need it for now.
Instead of OSM-1 for a power transformer, you can take 4 pieces of TS-270, although the dimensions are slightly different, and I only made 1 welding machine on it, so I don’t remember the data for winding, but it can be calculated.
We'll roll the throttle
We take an OSM-0.4 transformer (400W), take an enamel wire with a diameter of at least 1.5 mm (I have 1.8). We wind 2 layers with insulation between the layers, lay them tightly. Next we take an aluminum tire 2.8x4.75 mm. and wind 24 turns, making the free ends of the bus 30 cm long. We assemble the core with a gap of 1 mm (lay in pieces of PCB).The inductor can also be wound on iron from a color tube TV like TS-270. Only one coil is placed on it.
We still have one more transformer to power the control circuit (I took a ready-made one). It should produce 24 volts at a current of about 6A.
Housing and mechanics
We've sorted out the trances, let's move on to the body. The drawings do not show 20 mm flanges. We weld the corners, all iron is 1.5 mm. The base of the mechanism is made of stainless steel.
Motor M is used from a VAZ-2101 windshield wiper.
The limit switch for returning to the extreme position has been removed.
In the bobbin holder, a spring is used to create braking force, the first one that comes to hand. The braking effect is increased by compressing the spring (i.e. tightening the nut).
Many welders working in production have no idea what it looks like electrical diagram semi-automatic welding machine. They have never opened or repaired the device they work on. And if you don’t figure out the device yourself, you won’t need to pay a “round” sum to restore the circuit.
additional information
To facilitate the welding process and obtain a high-quality, even seam, devices with partial automation of work are used. Design of semi-automatic welding machines on our own will help resolve two questions at once:
Figure 1. Main parts of the automatic welding mechanism.
- Finance. Such a device will cost several times less.
- Repair. During production you will need to review various schemes semi-automatic machines, and then choose and assemble one that’s right for you.
Schemes of welding machines, the operation of which is based on the occurrence electric arc, their design and adjustment process have now become publicly available. This will help you find and manufacture a unique, reliable device.
A semi-automatic or automatic welding machine is a device that uses the principle of joining parts by heating them to the melting temperature with an electric arc. The process involves an electrode and a rapidly crystallizing seed, which, when heated, fills the seam, firmly holding the parts together as they cool.
Automation (partial) is solved like this:
Figure 2. Design of a semi-automatic welding torch.
- instead of an electrode, welding wire is used (on a reel or in sections);
- using a special device (mechanical or electromagnetic), the wire is continuously fed to the welding site;
- the speed of the process of approach of the electrode to the objects being welded is regulated by switching the gear in mechanical version or by supplying the appropriate current (voltage) in the electromechanical version.
The welder can only guide the wire along the seam.
To ensure protection working area from the influence of external factors, the devices are divided into devices for cooking:
- A wire with flux located inside it. Do-it-yourselfers almost never use this option because of the high cost.
- Cored wire in a gas environment. The option is widespread.
Return to contents
Basic Mechanism Designs
The device that supplies the electrode to the work area can be of two types:
- Pulling - pulls the wire to the welding site through a special channel in the torch itself.
- Pushing - the flexible electrode is pushed through the guide sleeve to the site of the future seam.
Figure 3. Electrical part of a semi-automatic welding machine.
Each of the devices can be made based on the windshield wiper of any car. The design of both mechanisms is almost the same and is something reminiscent of a laundry wringing device on old (soviet) washing machines. Picture 1.
The wire (1) is pulled through the rotation of rollers (2), which are rigidly fixed to the axles (3). One of the axles (upper) is pressed into a bearing (4) mounted on the frame (6). The second axis is the motor shaft. A lower bearing is required if a gearbox or transfer roller is installed instead of a motor.
For better wire grip, it is advisable to make corrugations or notches on the rollers. This entire device must be carefully insulated, because current is supplied to the electrode in contact with the rollers and frame. The mechanism must be placed on the burner through the insulating gasket or in close proximity to it.
The burner design is conventional. The only difference is the presence of a valve, which, when gas is supplied, closes the contacts of the wires going to the feed mechanism relay. The relay turns on the motor, which directs the wire to the welding site. Figure 2.
Partial automation of welding simplifies the process and improves quality weld. Big step in this direction can be done if you make semi-automatic welding with your own hands.
Currently, a lot is being done in terms of mechanization and automation welding work. Good results have been achieved in improving electric arc welding. Numerous drawings, diagrams and designs of devices have become available to many. All this allows you to make a fairly reliable semi-automatic welding machine with your own hands.
General information about semi-automatic machines
A modern semi-automatic welding machine is a device for electric arc welding using a consumable electrode. The main task of a semi-automatic machine is to ensure a continuous supply of electrode to the welding zone. This problem is solved by using a welding wire as an electrode, the supply of which is automated in terms of continuous supply. In this case, the welder moves the electrode itself along the seam manually. The wire feed speed is adjustable.
According to the degree of protection of the welding zone from environmental influences, devices are divided into semi-automatic machines for welding with flux-cored arc, welding in a gas environment and welding with special flux-cored wire. In the first case, the flux is part of the wire, it is homemade devices It is rarely used due to its high cost. The most common welding is in a gas environment, and the use of flux-cored wire is usually combined with the use of gas protection.
Semi-automatic designs
The most promising type of semi-automatic do-it-yourself welding machine is an electric arc welding machine in a protective gas environment. In this case, the main elements of the semi-automatic machine are: welding current source; burner with electrode and gas supply hose; shielding gas source; mechanical system with gearbox for wire feeding; process control and management system.
The wire feeding system is based on two mechanisms, therefore it is divided into a push-type system and a pull-type system, as well as their combined use. The first type is characterized by the fact that welding wire is pushed inside the guide channel (sleeve). With the second type, the feeder is located inside the torch and pulls the wire from the output spool.
The process control system must provide both the ability to regulate parameters (current, voltage) and the wire feed rate. IN homemade designs Both smooth and step control are possible. Promising automatic communication welding parameters with wire feed speed. The current source for welding can be a standard welding inverter or a homemade transformer.
Manufacturing of welding transformer
Figure 1. Diagram of the wire feed mechanism.
When choosing the power of a welding transformer, the diameter of the welding wire should be taken into account. So, in the case of using wire with a diameter of 0.8 mm, a current of 160 A is sufficient. The power of the welding transformer must be at least 3 kW. A ferritic metal in the form of a toroid is recommended as the core of the transformer.
The core cross-section is 40 sq.cm. The primary winding is wound from PEV or PETV wire with a diameter of 1.9 mm. The number of turns is 220. Winding is done on one side of the core with interference. The coils should fit snugly against each other. A paper, fabric or lacquer tape is applied under the winding and on top of it. The top protective winding is secured with tape.
The secondary winding is placed on the other side of the core. The winding is made with copper wire or busbar with a cross-section of at least 60 sq. mm. Number of turns - 56. Overlapping protective coatings, similar to the primary winding. Such a transformer has a power of 3 kW, welding current- up to 200 A.
Wire feeder
Figure 2. Burner assembly diagram.
Mechanism providing automatic feeding welding wire into the welding zone is one of essential elements semi-automatic welding machine. In homemade designs, such a mechanism can be made on the basis of a car windshield wiper, for example, a GAZ-69 car. The wire feed mechanism is combined with the welding torch. In Fig. Figure 1 shows a diagram of such a device: diagram of the welding wire feed mechanism where 1 is the base; 2, 10 — driving and driven feed rollers; 3 — bushing-bearing with lock nut; 4 — output shaft of the drive gearbox; 5 — bracket; 6 - guide; 7 - welding wire; 8 — holder axis; 9 — clamping bar; 11 — pressure spring; 12 — bracket; 13 — driven roller cage; 14 — driven roller axis; 15 — washer; 16 — spacer sleeve.
The welding torch is designed to be brought into the welding zone electric current, shielding gas and welding wire (electrode) simultaneously. In this case, electric current is supplied through the welding wire, and gas is supplied through a separate channel. The welding wire is fed inside a guide tube (you can use, for example, a sheath with a diameter of 1.2 mm for a car speedometer cable), on one end of which a guide tube with a thread of 4 mm in diameter is attached, and the other end enters the channel of the welding torch. The start button is attached to the burner channel using a bracket and connected to the cable. The gas supply hose is also connected to the burner channel.
Figure 3. Electrical diagram of the process control unit.
The burner itself is assembled from two identical halves, and all hoses, tubes and wires (cables) are assembled together and secured with a bandage.
The burner assembly diagram is shown in Fig. 2: assembly diagram of a welding torch, where 1 is a guide; 2 - channel for welding wire; 3 - channel-base; 4 — injector tube; 5 — gas hose; 6 - wire; 7 — start button; 8 — bracket; 9 - locking screw; 10 — brass nut; 11 — plug washer; 12 — bushing; 13 - casing; 14 - tip.
In the feed mechanism, you can use an electric motor with a gearbox from the drive of the glass cleaner of the GAZ-69 car. The output shaft is reduced to 25 mm, and a left-hand thread with a diameter of 5 mm is cut on it. The driven roller has the ability to rotate on an axis with a diameter of 5 mm, intersecting the bars and the frame formed by the holder and the bar.
In front, teeth are made on rollers (5 mm wide) so that gearing is created between them. The back side of the rollers is grooved (10 mm wide) to ensure wire grip. The driven roller frame at the end is seated on an axis intersecting the bracket and the bushing. A spring is installed on the second end of the frame to clamp the wire between the rollers.
The wire feed mechanism, gas valve, switch and resistors are installed on a PCB plate that covers the control panel. The output reel with welded wire is attached at a distance of about 20 cm from the feed mechanism.
Before starting welding, the guides must be brought closer to the rollers and secured with nuts. The wire is then pulled through the guides, feeder, torch channel and tip. The tip is screwed into the burner. Put on protective cover and is secured with screws. The hose is connected to the valve, and a gas pressure of about 1.5 atm is set on the reducer.
The operation of a semi-automatic welding machine largely depends on the control circuit for the process of feeding wire, gas and welding current.
In Fig. Figure 3 shows an electrical diagram of the process control unit.
The semi-automatic welding circuit carries out regulation in the following order. When switch SB1 is closed, when button SA1 is turned on, relay K2 is activated, through the contacts of which relays K1 and K3 are activated. Contact K1.1 opens the gas supply, contact K1.2 supplies current to the electric motor, contact K1.3 turns off the engine brake. Relay K3, using its contacts, carries out the reverse operation through certain time, specified by resistor R2. During this operating period, gas enters the torch, but welding is not performed.
After capacitor C2 is triggered, relay K3 is turned off and the feed mechanism motor is turned on, and after relay K5 is triggered, welding current is supplied. Welding begins.
When the SA1 button is turned off, relay K2 turns off, turning off relay K1. The feed motor is turned off and the brake is applied. Contact K1.1 interrupts the supply of welding current. Welding stops.
Assembly of a semi-automatic device
A welding transformer and its control unit are installed in the frame with the roof. A cable from the electrical network is connected to the transformer. The welding control circuit is assembled in a separate panel. The shield is connected by cable to welding transformer and a burner. A gas cylinder is connected to the burner. All necessary installations and adjustments are carried out. Welding using a semiautomatic welding machine begins after pressing the start button.
Tools and equipment
To manufacture a semi-automatic welding machine, the following equipment and tools are required:
- Bulgarian;
- welding machine;
- soldering iron;
- drill;
- hacksaw;
- vice;
- chisel;
- hammer;
- pliers;
- set of taps and dies;
- sharp knife;
- ruler.
Do-it-yourself semi-automatic welding is a completely reasonable solution. It is possible to make such a machine, but it requires a little effort and skill.
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, availability the necessary tool and desire.
Making a semi-automatic machine from an inverter with your own hands
Structure
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 network, alternating current is converted into direct current. This requires a special electronic module, a high-frequency transformer and rectifiers.
For high-quality welding work, it is necessary that the future device has parameters such as voltage, current and welding wire feed speed in a certain balance. This is facilitated by the use of an arc power source that has a rigid current-voltage characteristic. The length of the arc is determined by a rigidly specified voltage. The wire feed speed controls the welding current. This must be remembered in order to obtain from the device best results welding
The easiest way to use circuit diagram from Sanych, who long ago made such a semi-automatic machine from an inverter and successfully uses it. It can be found on the Internet. Many home craftsmen not only made a semi-automatic welding machine with their own hands using this scheme, but also improved it. Here is the original source:
Diagram of a semi-automatic welding machine from Sanych
Semi-automatic Sanych
To make the transformer, Sanych used 4 cores from TS-720. 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 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.
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.
A person who has certain knowledge and experience in the field of electronics is quite capable of coping with such a task as making a semi-automatic welding machine with his own hands or repairing it. It is enough to prepare a certain set of elements and devices. If we compare inverter semi-automatic machines with similar welding equipment, the former stand out, first of all, because they are lighter in weight, due to which there are no special difficulties in working with them. In addition to this, there is no need to resort to special devices to move them to another location.
The device of a homemade semi-automatic welding machine
If we briefly describe the operating diagram of the inverter apparatus, its essence is as follows: after current enters the rectifier, a pulsating voltage arises, due to which the filter is smoothed, as a result, a constant current is created at the output. Transistors make it possible to create alternating current from direct current, which has frequency indicator from 20 Hz and above.
Due to the voltage drop, its purpose can be in the range of 70-90 V, while the force demonstrated by the current can reach 200 A.
Such features allow a homemade semi-automatic welding machine to demonstrate similar qualities as most of such equipment.
However, repairing these devices may pose certain difficulties, given the presence of complex electrical circuits in the system.
Keeping in mind that an inverter works by changing AC current instead of using EMF frequency converter, this ensures the device is small in size and light in weight.
However, to repair such equipment, the owner must have certain knowledge in electrical engineering.
Semi-automatic device
According to the diagram, the mass of conventional electric welding equipment, which provides a current of 160 A, is no more than 19 kg. Against this background is an inverter with similar technical characteristics, weighs 2 times less, and the current strength it demonstrates can reach up to 250 A.
Moreover, each of the mentioned welding devices can be made by hand. According to the diagram, the equipment of the inverter semi-automatic welding machine includes not only a power source, but also a number of other required elements:
- burner;
- device for feeding wire;
- a flexible hose through which wire and gas flow under pressure.
Features of manufacturing a semi-automatic welding machine
Manufacturing an inverter-type semi-automatic device seems to be a rather difficult task to implement, since the owner will be required to independently create wire feeder.
Materials
If the owner is determined to achieve his goal, then in addition to the diagram he needs to prepare tools and materials, full list which includes the following:
- transformer providing current from 150 A;
- mechanism for feeding wire;
- a flexible hose through which gas is supplied;
- bobbin with wire;
- control device.
Feed mechanism is a very important component of welding equipment, since it is thanks to it that the wire will be fed into the welding zone using a sleeve.
Particular attention is paid to the feed speed of the welding wire, which should proceed at the same pace as the melting process of the consumable. It is the wire feed speed that largely influences how well the seam will be created. For this reason, it is advisable to include a device such as a speed controller in the welding system. Thanks to it, it will be possible to weld from any wire, regardless of the material and diameter.
Most often, wire with a diameter of 0.8 to 1.6 mm is used to create a weld. It must be placed on the reel, after which the inverter is charged for welding. It is advisable to ensure that the electrode wire reaches the burner automatically. Thanks to this, you can speed up the welding process.
The device that controls the operation of the inverter semiautomatic device is equipped with regulator for current stabilization. To ensure the required current value, the system is equipped with electrical chip, represented by a microcontroller operating in pulse-width modulator mode. An important parameter is the duty cycle, which affects the voltage created across the capacitor plates. And at the same time it determines the electric force demonstrated by the welding arc.
Features of transformer preparation
To get an idea of the features of preparing a transformer for the manufacture of a homemade semi-automatic welding machine, it is important to take into account the following point: in its design, this device does not differ from the one used in microwave oven.
The design of this device there are two reels containing isolated copper wire. They act as primary and secondary windings. It is this product that will play a key role in creating a homemade inverter.
Due to the mismatch in the number of turns of the wire, current flows first to the primary bobbin, and then due to the induction effect in the secondary bobbin, a decrease in voltage is observed, which leads to an increase in current strength. If it was decided to create an inverter semiautomatic welding machine based on a transformer that was used in a microwave oven, then certain changes will have to be made to its design.
This need is due to the fact that the voltage produced by this device exceeds the required value, at which it will be ensured normal operation welding machine. For this reason, the main task will be to increase the current and at the same time reduce the voltage characteristic. One thing worth mentioning important point: an increase in current strength can lead to ignition of the electrode and damage to the metal workpiece; if the current is too weak, then during welding work it will be impossible to ensure a sufficiently reliable seam.
At this stage it is important to perform correct calculations, otherwise the created semi-automatic welding machine will soon require repairs. If we return to the necessary changes in the design of the system, this implies alteration of the secondary winding: first you need to remove the old winding, carefully screw a new one onto it, for which you should use a wire with enamel-based protection. All turns must be placed very tightly, repairs should be carried out as carefully as possible, otherwise there will be a danger damage the primary winding.
You don’t have to dwell on such parameters as the thickness of the wire used and the number of turns, since their choice will be determined by the type of transformer being repaired. However, to calculate the optimal indicators, you can use an online calculator. After creation required quantity The winding should be protected with a current-insulating substance.
Housing selection, coil alignment and installation
Before you start self-assembly semi-automatic welding machine, the issue with suitable option housings. As an alternative, you can consider a box having the required dimensions, from sheet metal or plastic mass. The selected housing will serve as the place where the transformers will be installed, after which it is necessary connect their primary and secondary bobbins.
To effectively remove heated air and supply cold air, it should be provided in the body of the created semi-automatic device with your own hands A few dozens through holes . Buy welding holders cable can be found in a specialized store. It is impossible to create a homemade semi-automatic welding machine without a gas cylinder: it can also be purchased in a store or borrowed from an old fire extinguisher. When the investor is connected to the network, the microcontroller will immediately start working and configure optimal characteristics for welding. If there is a voltage on the cable other than 100 V, we can conclude that the device is faulty. In this case, you will need to diagnose and eliminate the cause.
Electrode wire feed speed device
Although manufacturers position welders as highly reliable devices, quite often they fail due to the wire feed regulator, which forces the owner to frequently repair it. If problems arise in the operation of this element, then in the future this may negatively affect the operation of the semi-automatic welding machine itself.
If the outcome is positive, the owner will only need to spend more time on welding and replace the electronic wire. Considering that the wire is fixed at the moment of feeding the welding unit nozzle, for repairs the owner will have to remove the nozzle and clean the contact area.
If problems occur in the operation of the wire feed control regulator, this allows us to conclude that the welding wire flow rate is not optimal.
Failure of the control regulator may be due to malfunctions in its mechanical part. The scheme used in it provides a pressure roller, which is equipped with a wire pressure level regulator, as well as a wire feed roller. The latter is characterized by the presence of two recesses from which welding wire with a diameter of up to 1 mm emerges.
After the regulator there is a solenoid, the main function of which is to control the gas supply. Considering that the regulator is a rather massive element, and its fastening to the device panel is ensured by only a few bolts, it would be correct to assume that the feed regulator does not have a reliable support. This feature can lead to distortion of the semi-automatic design, which can also cause its failure.
Conclusion
Despite the fact that it is offered for sale big choice various welding units, each owner can save money on its purchase, if you decide to make such equipment yourself. This idea is easy to implement for the reason that you can use materials and tools that are not difficult to find. At the same time, you should not be afraid that a homemade welding unit will quickly fail. The main thing is to follow the scheme for creating such equipment, and then it will work with optimal performance characteristics, which will allow you to create reliable welding joints.