Arc welding robots are widely used for a variety of materials, delivering high quality and consistency in the produced components. This method produces very strong, continuous weld fusion, and the consumables used can be adjusted according to the material type. Numerous power handling programs are also available to match AC or DC voltage and current settings, allowing for customized arc propagation based on the type and thickness of the material being welded.
Gas tungsten inert gas (GTAW) welding uses a non-consumable tungsten electrode to conduct current while simultaneously introducing filler metal into the arc and welding it to the workpiece. It is typically associated with a "precise" process. In use, filler metal is fed into the molten pool from the outside, requiring the operator to skillfully control the balance between the melting of the substrate and the addition of filler metal to create a defined solidification line. This type of welding does not require the introduction of additional filler metal.
Gas-shielded metal arc welding (GMAW) uses a wire electrode that also serves as filler metal to form the weld, enabling faster travel speeds and providing process tolerances for robotics, allowing the wire diameter to be maintained within approximately ±50%. GMAW welding uses welding material less than 1 mm thick, typically resulting in a smooth, uniform weld shape. In this process, the weld relies on the filler metal as the active electrode.
In recent years, combining the consistency and quality of GMAW production processes with the appearance of GTAW welding processes has benefited aluminum welding. The use of aluminum alloys is widely popular among automakers, as it reduces the weight of automotive components, thereby improving fuel economy.
In the automotive industry, another popular robotic welding method is resistance welding, also known as spot welding. This method achieves welding by passing an electric current between metal layers while applying pressure, without adding filler metal. For some applications, it may be more advantageous than arc welding. Spot welding is ideal for high-volume production of thin, stamped steel or aluminum parts. The process can be easily adapted to various sizes and styles of spray guns for different parts, and using a servo spray gun provides consistent force and welding results. For many manufacturers, it is an ideal tool for automation.
For rotary spot welding, a variant can be modified to use a wheel-shaped electrode extending along a continuous line for longer, seam-type welds. This is ideal for parts requiring liquid tightness, such as radiators or steel tanks.
Projection welding is another popular type of resistance welding. The physical projection of the part helps control the flow of the arc and allows multiple projections to be processed in a single cycle. Projection welding is often used to spot weld nuts or studs to plates to increase thread anchoring points and is ideal for stamped parts.
Robotic laser welding can produce strong, repeatable welds at relatively high speeds, resulting in greater productivity throughout the workshop and enabling manufacturers to weld materials once considered unweldable. This process is ideal for high-volume production, using a focused laser beam to provide precise heat input and achieve the desired weld. Robotic laser welding is a good option for metals of varying thicknesses.
When thermally conductive welding is used in conjunction with modulated or pulsed lasers, it requires heating the metal above its melting point while avoiding vaporization. The most common form is remote laser welding (RLW), which melts two thin sheets of metal using a non-contact laser welding technique. The laser head utilizes a relatively long support, 100 mm to 150 mm, to move the beam from the head to a focal point on the part. Lap welds are typically used because the target weld has few or no seams and requires an opaque outer shell.
When used with a high-power laser, keyhole welding involves melting and heating the metal until it evaporates, leaving a narrow, deep "keyhole." As the laser beam travels along the welding path, the molten metal flows around the keyhole-like opening and solidifies within the joint.
Besides laser welding, there are several other popular options for robotic automated welding of hybrid metals. Flow drilling is best suited for joining dissimilar sheet metal or extruded parts. This very clean, single-sided process utilizes the heat and friction generated during drilling by rotating a screw. This melts the base metal and uses the screw as filler metal, resulting in high shear and tensile strength.
Friction stir welding (FSW) is an innovative solution for joining alloys or dissimilar metals ranging from 0.5 mm to 65 mm in thickness. FSW is a solid-state joining process (where the metals do not melt) that requires a rotating router to apply pressure and friction to melt the metals. This process has proven effective for electric vehicle and aerospace components requiring exceptional weld strength, excelling in continuous welds, and requiring minimal consumables and no filler metal.
Laser weld seam tracking systems are a relatively new technology. This method can solve welding process problems such as workpiece blanking deviation, workpiece assembly deviation, tooling positioning deviation, and deformation.
From new material requirements to challenging solution specifications, the robotic welding process library enables manufacturers to adapt to evolving customer needs. Effectively utilizing any of these processes has the potential to increase throughput and product quality.
