Welding is the process of permanently joining metals by heating and fusing them. For this, a special tool is used – a welding machine.
Types of welding machines
There are the following types of welding:
- manual arc (MMA);
- argon-arc (TIG);
- semi-automatic (MIG/MAG);
- spot (SPOT);
- plasma cutting (PLASMA).
Manual Arc Welding Machine (MMA)
For welding, an arc is used that burns between the weld pool and the electrode. The latter is a metal rod with a special coating.
The arc is formed when the end of the electrode touches the metal to be processed. In this case, at the point of contact, the surface begins to melt. A weld pool is formed. The electrode is also melted and acts as a material for the weld.
By-products of the process are gas and slag. The second protects the seam from the effects of the external environment.
After metal processing, the slag is removed.
Argon arc welding machine (TIG)
It is used mainly for working with non-ferrous metals. Effective in aluminum processing. It is a kind of alliance of arc and gas welding.
TIG – Tungstreng Inert Gas. Translated means manual arc welding with non-consumable electrodes in an inert gas environment. Electrodes for it are made from tungsten, a refractory metal with a high boiling point (about 5900 ° C). Of the inert gases, argon is used.
During welding, argon does not allow oxygen to oxidize the metal surface, which positively affects its characteristics.
Semiautomatic welding machine (MIG/MAG)
It has a similar technology to work with TIG welding. The difference is that fusible wire is used as the electrode material, and a mixture of gases is used as a protective medium.
The most common mixture is argon and carbon dioxide.
The first provides protection from oxygen, and the second speed of penetration.
This type of welding has several advantages:
- ease of development;
- high speed of work;
- the ability to make a long seam, without the need for stops and frequent ignition of the arc;
- no need to clean the finished seam.
Spot welding machine (SPOT)
It is used to connect thin sheets of metal. Widely used in the automotive industry.
Sheets of metal are placed between a clamp of electrodes through which a high current is passed. As a result, the contact point is heated above the melting point and a strong bond is formed.
Plasma welding machine (PLASMA)
It is a cutting of metal by means of a hot plasma jet. An inert gas heated by an electric arc to a plasma state is supplied through a nozzle under high pressure.
The operating temperature reaches 30,000 °C, which makes it possible to cut even refractory metals at high speed.
Among the welding machines, 2 large groups stand out:
- welding machines for the home;
- professional welding machines.
Household are intended for private use. They operate on 220V and are designed for low current.
Professional ones can work at mains voltage of both 220V and 380V. They have a high current strength (over 200 Amps), and are designed for continuous operation in difficult industrial conditions.
The following types of equipment are used in welding work:
- semiautomatic inverters;
- generators (petrol or diesel).
How Welders Work
Depending on the type of equipment, the principle of operation varies.
transformer welding machine
This tool converts the electrical current and regulates it so that the welding arc is stable.
The principle of operation is as follows. On the core, acting as a magnetic circuit, the primary and secondary windings are located. In this case, one of them is fixed statically, and the second moves relative to the first along the magnistor. This ensures that the current is regulated. The main role of the tool is a step-down transformer.
This device, which is a power source, is based on the following elements:
- rectifier unit (thyristor or diode);
The tool works by supplying an electric arc with direct current. The current passes through the secondary winding to the rectifier unit. Rectifiers can be silicon or selenium.
An additional throttle on the device will allow you to adjust the settings.
Welding inverter machine
Unlike a conventional rectifier, in which a single rectification of the current is performed, the inverter undergoes multiple current conversion according to various parameters.
Alternating current is converted by the primary mains rectifier. After that, it enters the filter. In this case, the voltage indicators do not change. Then the current is fed into the frequency converter. The output is a variable high frequency parameter.
After that, the transformer lowers the operating parameter to the values of the open-circuit voltage of welding. Its rectification takes place in the secondary rectifying unit.
The difference between this tool and the above is that electrodes are not required when working with it. Welding is performed by melting a special wire in a gaseous medium. At the core is a conventional transformer.
The semi-automatic kit includes:
- power supply;
- wire feeder;
- connecting hoses and cables;
- – control system;
- gas-containing capacity;
Semi-automatic inverter welding machines
At the heart of this device is an inverter. The welding process is identical to a conventional semi-automatic. Combines the advantages and disadvantages of an inverter and a semiautomatic device.
Generator for welding machine
The main task of this unit is to convert mechanical energy into electric current.
Its main parts:
- stator with magnetic poles;
- anchor with winding;
In the armature winding, at the intersection of the turns with magnetic field lines (they are located on the stator poles), an alternating current arises. In the collectors, it is converted to direct current. Through the carbon brushes, it enters the clamps, and from them to the welding wires that lead to the electrode.
Characteristics of welding machines
This characteristic allows you to determine what percentage of the operating cycle time (for different manufacturers it can be 5 or 10 minutes) the device can operate continuously, and how much it needs to rest.
For example, if the duty cycle is 10 minutes and the switching frequency is 30%, then this means 3 minutes. continuous work, and the need for 7 min. rest after it.
Most often, equipment is equipped with a protection system based on this parameter. When the maximum load level is reached, the device will automatically turn off to prevent overheating.
In welding equipment, it can be:
Variable current used in household power supply. It has interchangeable polarity, in which “+” and “-” change places with a frequency of 50 Hz. Some welding machines are capable of increasing the frequency to high values.
Alternating current has no concept of polarity, so there is no risk of incorrect connection of equipment. It is used most often for working with ferrous metals.
The disadvantage of this type of current is that the frequent reversal of polarity results in strong spattering of the molten metal.
This, in turn, reduces the quality of the weld.
DC type of current has a constant and unchanging focus. Due to this, the amount of spatter is significantly less than when using alternating current, and the quality of the seam is better. When connecting equipment, it is important to observe polarity.
The technology for the production of devices that use direct current is much more expensive, since it requires the inclusion of rectifiers.
Scope of application: processing of non-ferrous metals and stainless steel.
Devices using both direct and alternating current are universal. They can work in different conditions and with different metal. The cost is an order of magnitude higher than a simple tool.
This characteristic indicates the voltage of the power supply for which the device is designed. Not only the voltage value itself is important, but also the connection method.
There are the following options:
- single-phase (1 pair of contacts “0” – “phase”). Voltage – 220V. Such a tool works from a household outlet, due to which it has become widespread. Due to the high level of consumption, the load on the network increases, so powerful devices may require connection directly to the switchboard.
- three-phase (3 pairs of contacts “0” – “phase”). Voltage – 380V. Tools with this voltage are not used in everyday life. They are mainly used in industrial premises with an appropriate network connection. Used for complex jobs that require high power.
- single-phase / three-phase. Voltage – 220V / 380V. Depending on the purpose of the tool, one of the values is key or additional.
This parameter is measured in kW (kilowatt) and indicates the value of the maximum power for which the welding machine is designed.
The higher it is, the more current the equipment is capable of producing. This allows you to work with thick metal.
Open circuit voltage.
A measure of the voltage that the tool outputs to the electrodes. The value of the parameter depends on the type of machine, the type of welding and the electrodes used. Usually ranges from 40 to 90V.
Minimum welding current.
The smallest value of current at which the machine is able to weld metal. The parameter is important for evaluating the suitability of equipment for working with thin metal, in which a large current value is detrimental.
Maximum welding current.
The opposite value showing how capable the equipment is of handling thick metals using large diameter electrodes. The dependence of the material thickness on the welding current can be tracked using special tables.
Minimum electrode diameter.
The indicator determines the minimum value of the electrode with which the device is able to work.
Maximum electrode diameter.
Reverse option. The range of electrode sizes must be selected based on the requirements of the work to be done (type of welding, metal thickness, etc.).
To facilitate the work of the welder, manufacturers equip the equipment with some useful features:
- Hot start. Designed to facilitate arc ignition. When the electrode touches the working surface, the current value briefly increases, and then returns to standard values;
- Sticking protection. In this case, the device automatically lowers the current to the value at which it is easy to disconnect the stuck electrode;
Advice! Sticking occurs from the use of raw or low-quality electrodes.
Thus, to reduce the risk of this situation, it is necessary to buy them in a trusted specialized store and store them in a dry place with low humidity.
- Arc forcing. With a critical decrease in the distance between the electrode and the metal, the device increases the welding current, which makes it possible to increase the melting rate of the electrode and the depth of the weld pool. Another way to avoid sticking;
- Transport wheels. Allow one person to move even heavy equipment.
Equipment and accessories
Depending on the specific model of equipment, the package may vary. However, there is a necessary minimum that must be present in each kit:
- welding machine;
- 2 welding cables (about 2 meters long);
- warranty passport;
- instructions for use.
Additional items may also be included in the kit:
- welding mask;
- carrying case;
- carrying handles;
- shoulder straps;
- brush for cleaning equipment.
To facilitate the work of the welder and the subsequent maintenance of the equipment, there are various kinds of accessories that can be divided into several groups:
Electrodes for welding machine:
- for welding carbon and low alloy steel;
- for surfacing;
- for welding cast iron;
- for welding non-ferrous metals;
- for cutting;
- for welding high-alloy steel;
- for welding alloyed heat-resistant steel;
- for welding dissimilar metals.
Sprays and pastes. The compositions are designed for different purposes:
- fire protection of surfaces in close proximity to welding;
- splash protection;
- non-stick protection of gas burners and others.
- welder’s mirror;
- construction pencils and holders for chalk talc;
- rulers and squares.
The accessories also include:
- Plasma cutters.
- Electric holders.
- Ground clamps.
- Welding cables.
- simple and inexpensive design;
- high reliability;
- ease of maintenance;
- Efficiency is about 90%.
- reliability of the weld;
- stability of the electric arc;
- low noise level.
- work accuracy;
- stability of the welding arc;
- the ability to work in a wide range of current;
- overload protection;
- the ability to work with any type of electrodes.
- high quality weld;
- small spatter of metal;
- high performance.
- electric arc stability;
- high quality weld;
- low sensitivity to power surges;
- the ability to work with all known types of electrodes;
- possibility of use in places where there are no sources of electricity.
- large dimensions and weight;
- high energy consumption;
- strong dependence on power surges.
- dependence on power surges;
- sensitivity to dust and shock.
- high price;
- sensitivity to contamination of the electronic board.
- low mobility;
- sensitivity to weather conditions.
- complexity of maintenance;
- high price;
- in comparison with transformers, low efficiency;
- high energy consumption.
How to choose
It is necessary to select a welding machine depending on the purposes and operating conditions. Before making a purchase decision, it is worth answering a few questions:
- In what conditions is the work planned (indoor/street)?
- Is the compactness and mobility of the tool important?
- Do you need more power (how thick is the metal planned to be processed)?
- Is there access to electricity at the place of work?
- What type of metal is planned to be processed?
Having decided on the volume and purpose of the work, it is easier to choose a device with exactly those characteristics that are suitable for specific conditions.
If the scope of work is small and does not require high accuracy, but there is no electricity on site, it is not necessary to purchase an expensive welding generator. It would be more logical to buy a compact single-phase device and a 220V gasoline / diesel generator.
Which welding machine is better
There is no specific model that would be better in all respects. It all depends on the specific needs and conditions.
Apparatus for a professional welder. In this case, a more versatile device is required, with high power and a wide range of settings to work in various conditions with different metals.
Household welding machine. For these purposes, there is no need to buy an expensive and powerful device. The potential of the tool will most likely not be used to the end, and it is not worth overpaying for it. An inexpensive machine for manual arc welding with alternating current will cope with household work.
In any case, you should pay attention to the following factors:
- terms of warranty service;
- level of service development;
- availability of spare parts.
Maintenance, care and prevention
Timely maintenance, care and prevention of welding equipment are essential tools for a long service life. Regular maintenance of these works ensures good performance and will help to avoid serious breakdown in the future.
It is necessary to carry out the following actions:
- regular checks of the main elements of the device to identify external signs of a malfunction (violation of insulation, melting of contacts, etc.);
- cleaning and lubricating parts;
- performance testing and analysis.
During operation, keep the power supply away from heat sources, protect it from mechanical damage and precipitation.
Violation of safety regulations when working with welding equipment can lead to serious consequences:
- injuries (electric shock, burns, mechanical damage);
- death of people.
To be allowed to work, a welder must have:
- vocational training;
- documented work permit;
- medical work permit.
To avoid unpleasant consequences, the following precautions must be observed.
- Wear a dry protective suit and leggings to avoid electric shock. It is forbidden to touch with bare hands the electrodes and the housing of the equipment under voltage. Be especially careful when working in high humidity conditions.
- The welding helmet will protect against arc radiation and damage to the face of the welder.
- The room in which work is carried out must be well ventilated to prevent poisoning by gas and smoke.
- At high noise levels, hearing protection is required.
- There must be no combustible and flammable substances near the welding work. Fire extinguishers should be available in the immediate vicinity.
Manufacturers of welding equipment set different warranty periods. On average, it is from 1 to 3 years. Terms of warranty service for each model are individual. They can be found in the technical data sheet or on the manufacturer’s website.
The warranty is calculated from the moment the device is handed over to the buyer. In addition, free scheduled equipment maintenance may be offered as part of the warranty program.
- replacement of electrodes in agreement with the owner;
- parameter testing.
The warranty does not cover equipment:
- having external damage;
- modified by the owner;
- used in unacceptable conditions;
- having traces of unauthorized repair;
- operated with violations of requirements;
- with damaged markings;
- completely exhausted the resource declared by the manufacturer;
- with an expired warranty.
Also, the manufacturer’s obligations do not apply to:
- individual parts subject to natural wear;
- parts whose wear depends on operating conditions;
- equipment adjustment.
If the welding equipment breaks down due to the fault of the manufacturer, the user is entitled to a free repair. To do this, you must personally or by mail (I use protective shipping packaging) send the equipment to the warranty service center. In this case, be sure to present the warranty card.
Important! The warranty period is extended by the time of repair and shipment.
Claim work with buyers is regulated by the Law on the Protection of Consumer Rights. In accordance with its requirements, the repair period cannot exceed 45 calendar days. For each day of delay, the consumer has the right to demand the payment of a penalty fee.
Faults and repairs
Common malfunctions and breakdowns depend on the specific type of welding machine.
Malfunctions of welding transformers.
Poor contact in the terminal block to which the welding cables are connected. Leads to strong heating of the connection, destruction of insulation and short circuit. It is eliminated by sorting out the heating connection, stripping the contact group and clamping them for tighter contact.
Spontaneous shutdown of equipment. Occurs immediately after the device is connected to the network due to protection operation. Probable causes are a short circuit in the high voltage circuit, between the turns of the coils, as well as a malfunction of the capacitors. For repair, it is imperative to disconnect the device from the mains and eliminate the defect by restoring the insulation or replacing the capacitors.
Excessive transformer hum. Often accompanied by overheating. The likely cause is loose bolts or transformer overload. Also, buzz occurs due to a short circuit between the cables or sheets of the magnetic circuit.
Strong heating of the device. Most often occurs due to exceeding the permissible load level.
The limit values for the declared current and electrode diameter must be observed.
Otherwise, the equipment may fail.
Lack of welding current. Occurs due to low mains voltage or a breakdown of the current regulator.
Consumption of a large amount of current without load. The reason is the closure of the turns of the winding. The insulation needs to be restored. For the same reason, a sudden break in the welding arc is possible without the possibility of its restoration.
Malfunctions of welding inverters.
Transistor burnout. It is considered a weak point of inverters. In the event of equipment failure, it is necessary to first check the transistors. To check them, you need to use a multimeter.
Breakage of driver elements. Checked with an ohmmeter. If necessary, defective elements can be replaced with suitable analogues.
Defective input and output rectifiers.
Control board failure. The most complex piece of equipment. Performance is checked with an oscilloscope.
Arc instability. Occurs due to incorrect current setting.
Overheating of the device. Probable causes are long work under heavy load, failure of the cooling system, or contamination of the board.
It is quite possible to repair transformers with your own hands. Welding inverters have a more complex design, and for their repair it is necessary not only to have the appropriate equipment, but also to have special knowledge and skills.
It should be remembered that the repair and maintenance of welding equipment can cause serious harm to health. In the absence of the necessary knowledge and experience for these purposes, it is better to turn to professionals.
The devices of this brand are produced exclusively on the basis of inverter-type equipment. Joint production of the AURORA group of companies and the Chinese company RILAND Industry, where they assemble equipment for Russia. The official website of the manufacturer is www.aurora-online.ru.
The company offers a wide range of welding equipment in all areas: MMA, MIG/MAG, TIG, SPOT, PLASMA.
Warranty for all types of tools – 2 years.
Italian company, leading European manufacturer. The beginning of the production of welding equipment – 1963. Start of deliveries to Russia – 2002.
Specializes in the manufacture of all known types of tools and accessories. Production is established in Italy. The official website is www.blueweld.ru.
Warranty – 1 year.
German manufacturer of welding equipment. Production is established in several countries of Europe and Asia. A wide range of equipment and accessories for various purposes (inverters, rectifiers, transformers, semiautomatic devices).
Official site – www.brima.ru.
Warranty – 1 year.
Manufacturer of welding equipment, accessories and garden equipment. It offers various equipment for welding and cutting metals, as well as MMA-MIG-MAG-TIG welding multisystems.
The official website of the company’s online store is elitech.com.ru.
Warranty – 1 year.
The company is engaged in the manufacture of inverter welding machines. The range of models is small. Official website – www.eurolux-russia.ru.
Warranty – 1 year.
Italian brand made in China. A wide range of welding equipment and accessories. It has representative offices and service centers in 16 cities of Russia, which greatly facilitates maintenance. Official site – foxweld.ru.
Warranty – 1 year.
A German company producing various types of equipment for construction and repair: internal vibrators, drills, screwdrivers, spray guns, etc. Welding tools – inverter type. Factories are located in Germany and Switzerland.
The company has its own staff of specialists who create new technologies. Official website – www.fubag.ru.
The warranty for equipment purchased after April 1, 2014 is 2 years. Prior to that, it was 1 year.
Russian manufacturer of welding equipment: inverters, semiautomatic devices, devices for argon-arc and manual arc welding. The company positions itself as a manufacturer of tools adapted to harsh climatic conditions. Official website – www.kedrweld.ru.
Warranty – 2 years.
An American company that manufactures, among other equipment, inverter welding machines. This direction is not the main one. It has a wide network of service centers. The official website is www.onlypatriot.com.
Basic warranty is 1 year. In the case of purchase of equipment for personal use, an extended warranty period of 3 years is provided. At the same time, every 6 months, the consumer is obliged to undergo scheduled maintenance at the company’s service center.
Another American manufacturer of equipment for construction and repair. Offers, among other things, welding machines: inverters and semiautomatic devices. Has a research center. It has a network of authorized service centers. The official website is www.ru.redverg.com.
Warranty – 1 year.
One of the most popular manufacturer of inverter welding machines on the market. In addition to them, it specializes in the manufacture of voltage stabilizers. Developed service. Official website – www.resanta.ru.
Warranty – 1 year.
Russian manufacturer of power tools. Assembles inverter and semi-automatic welding machines. It has a wide network of service centers. Official site – stavr.rf.
Warranty – 2 years.
A company specializing in the production of inverter welding machines. Products are assembled in a Chinese factory. Official website – www.svarog-rf.ru.
The warranty period, depending on the equipment, is from 2 to 5 years.
British company producing welding equipment and accessories of various kinds. It has a good network of service centers. There is no official website.
Warranty – 3 years.
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