What machining processes are included in welding robots?

Welding robots are devices that integrate automated welding technology and can perform various welding processes. The process types are mainly classified according to the welding principle, heat source, and application scenario. The following is an analysis of the common process classifications and characteristics of welding robots:

I. Arc Welding Process (Most Mainstream Type)

Utilizing the high temperature generated by an electric arc to melt the base material and welding wire, forming a welded joint. Suitable for most metallic materials.

1. Gas Metal Arc Welding (GMAW)

Principle: An electric arc is generated between the continuously fed consumable electrode (welding wire) and the base material, using inert or active gas to protect the weld pool.

Subtypes:

MIG Welding (Inert Gas Metal Arc Welding): Uses inert gases such as argon and helium. The arc is stable, and the welding quality is high. Suitable for non-ferrous metals such as aluminum, stainless steel, and copper.

MAG Welding (Active Gas Metal Arc Welding): Uses a mixed gas of argon + carbon dioxide, oxygen, etc. Low cost and suitable for carbon steel and low-alloy steel, such as automotive body welding.

Robot Application: Equipped with a wire feeding mechanism and gas flow control system, it can achieve high-speed welding and complex trajectory tracking.

2. Gas Tungsten Arc Welding (TIG Welding / GTAW)

Principle: Uses a tungsten electrode as a non-consumable electrode to generate an arc that melts the base material. Filler wire (optional) is added, and argon gas protects the weld pool. The arc is stable, and the weld is aesthetically pleasing.

Characteristics: High welding precision, suitable for thin plates (0.5mm~3mm) and precision parts, such as aerospace titanium alloy components and stainless steel medical devices.

Robot Configuration: Requires a high-precision wire feeding device (if filler wire is used). The welding speed is slower but highly controllable.

3. Carbon Dioxide Gas Metal Arc Welding (CO₂ Welding)

Principle: Uses carbon dioxide as a shielding gas, consumable electrode arc welding. Low cost and high deposition efficiency.

Application: Mainly used for welding thick plates of carbon steel and low-alloy steel, such as steel structures and engineering machinery. Robots can be equipped with oscillating functions to improve weld formation.

4. Submerged Arc Welding (SAW)

Principle: The arc burns under granular flux, and the welding wire melts, with the flux forming slag to cover the weld. High thermal efficiency and stable weld quality.

Robot Application: Suitable for long straight welds or thick workpieces (such as pressure vessels and ship decks). Requires a cantilever or gantry robot system.

II. Resistance Welding Process (Suitable for Thin Plate Connection)

Resistance heat is generated by current flowing through the workpiece contact surface and adjacent areas, heating and pressing to form weld points or welds.

1. Spot Welding

Principle: Uses columnar electrodes to apply pressure locally to the workpiece and apply electricity to form a spot-like welded joint.

Robot Application: Automotive body welding (such as doors and chassis), equipped with multi-spot welding guns or servo welding tongs to achieve high-speed mass production.

2. Seam Welding

Principle: Uses a rotating disc electrode to clamp the workpiece and apply electricity to form continuously overlapping weld points (welds), with good sealing.

Application Scenarios: Fuel tanks, pressure vessels, and pipeline welding. The robot needs to precisely control the electrode pressure and welding speed.

III. High-Energy Beam Welding Process (High Precision, High Energy Density)

1. Laser Welding

Principle: Uses the high energy density generated by focusing a laser beam to melt the base material, which can achieve deep penetration welding or heat conduction welding.

Characteristics: Fast welding speed (can reach over 10m/min), small deformation, high precision. Suitable for thin plates (0.1mm~2mm) and precision parts (such as battery tabs and electronic components).

Robot Integration: Equipped with a fiber laser source and a galvanometer scanning system, it can achieve three-dimensional complex trajectory welding.

2. Electron Beam Welding (EBW)

Principle: A high-speed electron beam bombards the workpiece surface, and kinetic energy is converted into heat energy to melt the material. It needs to be carried out in a vacuum environment.

Advantages: Large weld penetration-to-width ratio (can reach 50:1), suitable for thick parts (10mm~100mm) and high-melting-point materials (such as titanium alloys and tungsten alloys), such as aerospace engine components.

IV. Other Welding Processes

1. Stud Welding

Principle: One end of the stud is in contact with the base material, and electricity is applied to generate an arc to melt the contact surface, and then quickly pressed to complete the welding.

Robot Application: Stud fixing of automotive bodies, welding of steel structure connectors, equipped with an automatic stud feeding mechanism and welding gun.

2. Friction Stir Welding (FSW)

Principle: Uses a rotating stirring pin to rub against the base material to generate heat, causing the material to plastically deform and form a solid-state connection without melting.

Characteristics: Suitable for light metals such as aluminum alloys and magnesium alloys. High weld strength and small deformation. Used in aerospace and rail transit (such as high-speed rail car floors).

3. Plasma Arc Welding (PAW)

Principle: A compressed arc forms a plasma beam with higher energy density than TIG welding, enabling penetration of thicker materials (3mm~10mm). It offers faster welding speeds and is suitable for welding stainless steel and titanium alloy pipes.