Automated welding

Types of semi-automatic welding
Semi-automatic machines used in arc mechanized welding. In their design, among other components, includes burner, which is moved manually, and automated device for the welding wire.
Welding machines are widely used in all areas of construction and industry. All the difficult places available for semi-automatic welding. Part of the software is equipped with semi-automatic device in the control unit.
Unified system of notation allows to choose wisely for each activity required brand welder.
The designation shall appear semiautomatic first letter. The first indicates the product, for example: P - semi, I - installation.
The second letter indicates the welding method: W - hose, D - for arc welding.
The third letter gives information on how to weld in a particular environment, such as: F - Fluxing, FG - flux-gas. The presence of the third letter is not necessarily, and it may be absent. Usually all are semi MAG welding in environment, so repeating it in the designation does not make sense.
After the letter index next digit. The first shows the current value in the hundreds of amps. The second and third digits indicate the modification of semiautomatic.
After the third digit is followed again by a letter indicating the climatic conditions, such as: U - an area with a temperate climate, CL - an area with a cold climate, T - tropical.
The last digit indicates the category of the room: 1 - in the open air, 2 - cold rooms, 3 - room with natural ventilation, 4 - room with forced ventilation and heating, 5 - a room with high humidity. Electrode wire is fed by a semi-automatic banjo hose (hence the name "semi-automatic hose"). All models are interchangeable and are unified, have a common interface and diameter of the electrode wire, the energy parameters they also coincide. This compatibility allows to use electric motors, burners, coils of wire and feeders made from devices of different brands. The figure shows a diagram of 122 semi-automatic welding in inert gas.

Схема сварочного полуавтомата для сварки в среде защитного газа

Fig. 122. Scheme of welding machines for welding in inert gas

The components of such a device is removable gas burner feeder, hose wire feed, tape storage wire, gas hose, control unit, the power supply control circuit wire, gas equipment, cables.

Device torch
Burner used to feed into the combustion zone shielding gas or flux and welding wire. Torch handle is durable and convenient. It is usually made of molded insulating material. It is equipped with safety guard and starter button. The main elements are the burner nozzle and the supply current of the tip (Fig. 123).

Горелка с плавящимся электродом в среде защитного газа

Fig. 123. Torch with consumable electrode inert gas: 1 - tube shielding gas, 2 - input consumable electrode (wire), 3 - supply of shielding gas to the nozzle 4 - working nozzle, 5 - jet shielding gas around the electrode, 6 - electrode location of the arc, 7 - the start button, 8 - guard, 9 - reducing bush, 10 - net (cermet) insert.

Burner mouth is constantly exposed to molten metal stick. This disadvantage is eliminated nozzle chrome plating, polishing or replacing the material in ceramics. When the welding current is equal to 325 A or more, the burner nozzle is further cooled. Every six months, to be replaced with a new burner.
Tips for applying current calculated by about 5-10 hours of continuous operation. They are made of various materials - copper, bronze, an alloy of copper and graphite, copper and tungsten. The shortest life - a copper tip.
Copper-graphite ferrules to their small life, provide better contact welding and ensure good sliding, which is especially important when welding aluminum wire. Longest job offer tips on copper-tungsten basis.
When welding low alloy and carbon steels in carbon dioxide environment used poluavomaty PDG. PDG consists of a DC source, wire feeder, gas equipment, welding torches and connecting hose. In machines of this type are used burner brand GDPG. In case the product is available standard power supply. With the help of the control unit can be done in setup mode the following: inclusion shielding gas to adjust its flow; wire feed at a given speed, type of cycle, setting a certain type of welding (long, short, point stitching).
If a semi-automatic welding works in a mode, the command of the beginning and the end of welding provides the control unit. At the beginning of the control unit includes a welding shielding gas and power supply, and a little later (after 0.5) includes wire feed with a stable rate.
When the command to stop the motor off welding wire feeder and its inhibition occurs, take some time (up to 5), the power supply and turn off gas flow.
Semiautomats PDG designed for use in moderate climates. Stamps PDG-305 and PDI-303 are designed to work primarily in a cold climate. If the work will involve semi-PN-13 or CDP-516, the welding will be carried out with steel and flux cored wire.
If you have to welding of titanium alloys, then fit semiautomatic FS-109. It is designed for welding of titanium alloys in the solid electrode wire argonosoderzhaschih gas mixtures. With this machine you can to weld in all positions except the ceiling. As used herein the feeder mechanism "Izaplan"; generator GIIDS-1 provides welding in pulsed mode, to force the cooling airflow area seam semiautomatic used cooler. The wire feed speed is controlled by varying the speed of rotation of the motor shaft. Contact pressure feed rollers can be adjusted using the conical shell a head.
The universal semi include A-1197 and FS-112. A-1197 is used for welding in carbon dioxide and submerged powder and solid wire. This automatic gas and flux equipment is interchangeable: if gas installations replaced by fluxing, the circuit is ready for welding.
The same applies to the types of burners used. When working in the shielding gas burner GDPG, which can optionally be replaced by a different name, such as A-1231-5-F2 (during welding fluxes).
Self-shielding cored welding wire used semiautomatic FS-112. If you have to solid wire welding in carbon dioxide, the FS-112 provides for this kind of work possible conversion. Software device built into the control unit descent control unit 1, allows you to program a linear dependence of the welding current at the electrode or replacement of welding. Thanks to this device facilitates automatic adjustment and ensures the quality of welds.

Management of semi-automatic welders
Depending on what type of motor feeder built into the concrete machine, all their control systems are divided into three groups.
The first group includes semi-operated DC motor, which is connected to the power supply of the arc.
The second group includes semi-operated asynchronous motors.
The third group includes the semi-operated DC motors that regulate smooth wire feed in a range. Automatic control system is presented in the form of individual units.
For the first group of the control system to remove blocks 3, 5, 7. Here, the wire feed speed is regulated in a narrow voltage range of the arc, which affects the use of the scheme.
The second group of control starts when you turn off from the work units 3 and 5. In this scheme, the performance of the semi-automatic machine is reduced due to the constant speed control wire feed.
The most advanced is the third group of the control system. It does not have the drawbacks of the first two systems. Thyristors and transistors or speed wire feed in a wide range. This affects the reliability of the system as a whole and to reduce the size of equipment.
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