What is robotic welding and how does it work?


Written by

Robert Graham

Manufacturers are increasingly turning to robotic welding, which usually combines a six-axis robot, welding equipment, sensors, and software, to perform repeatable welding tasks automatically.  

Businesses in numerous industries face an unprecedented shortage of skilled welders. Trade groups, including the American Welding Society, believe the shortfall will reach between 375,000 and 400,000 welders by 2024.  

Robot welders are part of the answer to that problem, as they are precise and deliver reliable, repeatable results with less waste and greater efficiency.

What is robotic welding? 

Historically robotic welding arms have been limited to large-volume, highly repetitive applications such as mass vehicle manufacturing. This is because a lot of manual software programming is required to translate a CAD design into welding instructions. This skilled and time-consuming task demands strict tolerances at the assembly stage for the parts to be welded. Manufactures also use cobots which involve operators physically manipulating the robot head around the area to be welded and then storing the data for use with future welds of the same type.  

This reliance on labor intensive software programming has started to shift. New technologies that reduce the need to manually select weld lines, plot movements and refine engineering processes are starting to appear on the market. This has opened robotic welding to a whole new segment of the industry that offer a high mix, low volume manufacturing service.

Articulated six-axis robot arms   Articulated six-axis robot arms

Robotic welding today is a versatile technology and is not limited to a certain type of welding. Depending on the configuration, robotic welding can be used for many welding processes, including:

  • Arc welding 
  • Resistance welding 
  • Spot welding 
  • TIG (tungsten inert gas) or GTAW (gas tungsten arc welding) 
  • MIG (metal inert gas) or GMAW (gas metal arc welding) 
  • Laser welding 
  • Plasma welding 

Manufacturers may choose to use: 

  • Robotic arms (articulated) 
  • Six-axis robots 
  • Cartesian or Gantry robots 
  • SCARA robots 
  • Cylindrical robots 

As long as the robot can be fitted with a welding tool, it can be used for robotic welding. The two most popular types of welding robots are rectilinear (Cartesian or Gantry) and articulated (six-axis). Rectilinear robots move in three axes, while articulated robots combine a three-axis “arm” and three-axis “wrist” that work together much like a human arm and wrist. 

How does robotic welding work? 

In general, there are three major components of a robotic welding system:  

  • The robotic apparatus (which holds and operates the welding equipment),  
  • The welding equipment 
  • The robotic welding software, sensors, and/or control mechanisms used to guide the robot automatically during operation. 

Typically, the part or parts that will be welded together first must be placed in a fixture or jig. For maximum efficiency, the fixture can be rotated or switched out automatically so a human operator can prepare a new set of parts while the robot welds the first set. 

Guided by the software (usually a computer numerical control, or CNC, system), the robotic arm then moves into a pre-programmed position and creates the weld as specified. Many robotic welding systems are capable of performing more than 30 welds every minute. or more. 

The actual welding process starts with the power source, which delivers electrical power to the torch. With arc welding, the flow of current generates temperatures as high as 3,600°C / 6,500°F, which melts the solid electrode wire and the metal of the part, joins the two parts, and then solidifies into a strong, solid bond after cooling. Electrode wire is delivered to the welding point by an automatic feeder. 

Sensors may also deliver information about the welding process and part geometry back to the software or control system so it can adjust the robot’s movement in real-time. In between welds, the robotic apparatus may also move its torch to a separate area for cleaning away spatter. 

Is robotic welding a fully automated process?  

Robotic welding is not a fully automated process. A human operator may still be required to replace the wire supply in the feeder, arrange the part in a fixture, or supervise the process. In many cases a human operator is also responsible for programming the robot, although this is changing. 

Automated Welding Robot on Vehicle production lineFinding welds with Oqton's software for robotic welding

Where is robotic welding used?

Robotic welding is used in a wide range of heavy industrial applications. Again, it is most often used in applications that do not require a highly skilled professional, such as short welds and predictable welds that don’t need continuous real-time adjustment. The majority of applications are high-volume, mass production assembly lines. However, new programming solutions are making it economically feasible to use robotic welding for lower-volume jobs. 

Here are a few popular examples of uses of robotic welding:

1. Metal fabrication. The metal fabrication industry serves many other industries, including mining, construction, manufacturing, marine, automotive, aerospace, and energy. Welding is a critical process for metal fabrication, and robotic welding can be used to perform any number of tasks, from steel beam assembly to shipbuilding.

2. Automotive.
Robotic welding is a good fit for the automotive industry, which thrives on rapid production. In addition, welding in automotive applications aligns very closely with the capabilities of robots. The same weld is made repeatedly with minimal variation, the welds require high accuracy, and the process may involve conditions that pose a threat to human operators. In the automotive industry, robotic welding may be used to join parts on a vehicle frame, attach the motor to the vehicle, build water pumps or other complex metal parts, and apply metal fasteners.

3. Rail.
Robotic welding is often used to manufacture a wide range of metal bolsters, components that connect the ends of container cars. Rail manufacturers must be able to quickly fulfill large orders of rail cars for many different customers. Robotic welding systems can be pre-programmed for any of these bolster designs, allowing them to work very efficiently when the order arrives. 

Learn more about robotic welding

Keep reading to learn about the advantages of robotic welding over manual welding.