What Is Robotic Welding?- Process, and Application

Welding is the procedure whereby two materials are melted together through heat, intermixed, then cooled to create a strong join of a material and/or a filler.

In the welding field, welding robots can either be new or used when it comes to welding processes, where the weld needed is repetitive, and quality and speed are very important.

Robotic welding is an automated process it is more efficient, produces better consistency, and increases the return on investment.

What is Robotic Welding?

Welding robots are programmable mechanical devices (robots) that fully automate a given welding process by both welding and manipulating the part.

Automated welding processes will include welding processes such as gas metal arc welding (GMAW), and those forms are not easily classified as robot welding, since the human operator often prepares the materials for welding.

Robot welding is commonly used for resistance spot and arc welding in high production situations, such as the automotive industry.

Industrial robot welding is a technology that is relatively new, even if the technology was introduced into the US industry in the 1960s. Industrial robot usage for welding begun climbing in 1980s when automobile manufacturing started using to robots for spot welding.

Since then the number of robots being used in industry has climbed, and also the number of uses with the robotic technology.

In 2005 there were more than 120,000 robots being used in North American industry, with half of them, or more, in welding applications. The growth is mostly limited by the costs of equipment and therefore constrained to high-production applications.

Robot arc welding has just begun to grow rapidly in use, and now controls around 20 per cent of industrial robot applications. The main elements of arc welding robots are the manipulator, or mechanical unit, and the controller which is the brains of the robot.

The manipulator is the motor that moves the robot, and the designs can be categorized into a few common types of systems, such as SCARA robots and cartesian coordinate robots that provide different coordinate systems to orientate the robot arms.

The welding robot may weld a pre-programmed position, have a guided robot with machine vision, or weld by a combination of programming and machine vision.

However, many advantages for using robotic welding has made it a technology that provides positive return on investment, and consequently as a technology that helps many original equipment manufacturers increase accuracy and repeatability, and improve throughput

The technology surrounding signature image processing has been developed since the late 1990s for the purpose of analyzing, in real time, electrical data being collected from automated, robotic welding, and therefore optimizing the welds created.

Robotic Welding Equipment

Robotic welding is an integration of welding, robotics, sensors, control systems, and artificial intelligence. The components are the software (with specific programming), the welding equipment (delivering energy from the welding power source to the workpiece), and the robot (using the equipment to make the weld).

The robot has process sensors that will measure the parameters of the welding process, and geometrical sensors that will measure the geometrical parameters of the welds.

By gathering and analyzing the input information from the sensors, the control system will modify the output of the robotized welding process according to the welding procedure specifications (WPS) described in the programming.

Depending on the application, the robots may be robotic arms or robot portals. Typically, six-axis industrial robots are used, which consists of a three-axis lower arm and a three-axis wrist, because these robots allow the welding torch to be mounted at the wrist to achieve all the necessary positions for three-dimensional welding.

The system must be integrated with the robot and the welding equipment needs to work with and preferably be specifically designed for robotic welding, then the robot can control all processes.

How Robotic Welding Works?

Whenever robots are used for any type of process, the process must be modified for automation. The same is true for welding. Welding uses various tools that do not translate to the manual process. People are not programming, like how a welding robot does.

The robot physically has an arm that can move in three dimensions for rectilinear types of robots and through additional planes for articulated types. The robot has a wire feeder that provides filler wire as needed by the robot for the welding task.

At the end of the arm, the high-heat torch melts metal and starts the welding process. Temperatures are high enough (thousands of degrees) that using robots enhances the safety for people.

Certified human operators are required to be nearby when robotic welding is performed. The operator should have welding certification through the American Welding Society, AWS. AWS certifies both manual-welders and robotic welding arm operators.

The operators have a teach pendant that they use to program the controller. The teach pendant creates new programs, moves the arm, and changes parameters for the welding process. The operator completes the welding process by using buttons on the operation box.

Welding robots utilize a tool on the arm to melt the metal to connect the two pieces of metal that are being welded. The wire feeder supplies more metal wire, as desired, to the arm and torch.

After waiting for more parts to weld, the arm moves the torch when not in use, to the cleaner to clean the arm of splattered metal that could otherwise solidify in place.

Because one of the main purposes for robotic welders is to protect humanity, the automated systems have many safety features. An arc shield protects people from high-heat mixtures of oxygen with the arc. Enclosed areas provide protection from temperature and brightness for the workers.

Benefits of Robotic welding

There are numerous benefits from using automatic / robotic welding systems for a factory when compared to manual welding, including increased speed and reliability with consistent cycle times, fewer interruptions to deliverables, and improved welding performance.

In short the use of welding robotic automation ultimately results to less time consumption and will allow to reduce the direct labour costs and liabilities with safety and save materials too.

Robotic weld cells provide an even safer working environment with a reduction in arc flash, spatter and the inability to get close to the robot and the parts. A robot welder is far more consistent and can move quickly from part to part, increasing overall speed.

• Spending Less Time: Robotic welding systems will provide a consistent and reliable short product cycle, with new or used welding robots there are fewer errors associated with traditional manual welding. Unlike manual labourers, robots don’t take breaks, vacations, etc. Your work can be completed continuously, akin to a 24/7 operation, dramatically improving your throughput & productivity.
• Reduce Cost of Direct Labour & Safety: The cost of manual welding is costly; both in time, skilled welders, and concentration. It is also hazardous. Flash, fumes, sparks, and heat make manual welding a difficult, stressful, and dangerous job. Robotic welding manages the safety of workers and saves money on direct labour costs. Robotic systems can endure the hazard and typically boost production. Insurance and accident related costs are also reduced.
• Save Materials: Even trained and skilled welders make mistakes. With new and used robotic welding systems everything is controlled even power and wire with a new and used robotic welding system. The use of unused robotic systems conserves energy by utilizing consistent run times (less start-ups). The weld that is produced by robotic welding systems is consistent, therefore more accurate and has lower material costs, therefore conserve your material and improve your product quality!

Some companies migrate to robotic welding implementations gradually, in that they begin with a single welding cell while some convert to fully automated welding.

Robots can assist if the access to a part is limited or difficult to reach. Manufacturers have designed so that the nimble robotic arm can reach even the more limited areas.

Limitations

When using robots for welding, one challenge is the typical limitation of movement imposed by the cables and hoses used for current, air and other effects.

The swivel is a solution to this problem by allowing the flow of compressed air, cooling water, electric current, and signals through one rotating assembly.

The swivel assembly also allows for offline programming since the cables and hoses can attach to a pre-defined robot arm path.

Other limitations of robotic welding:

• End-user programming is complex, difficult to use, and only for specialists, and limiting APIs complicate or make things as simple as possible.
• HMI (Human-Machine Interface) doesn’t work – this needs customization and training. It is hard to customize robotic welding systems.
• Connectivity issues include a lack of inter-connectable standards.
• Replaces human labor.
• Technology is quickly outdated.

Robotic Welding Processes

Welding is a specialization that typically does not have an associates or bachelor’s degree requirement, but it does require a quality education and skill. Unfortunately, the number of professional welders does not keep up with the need for welders across the country.

The American Welding Society reports that in 2022, the welding industry will see a shortage of 450,000 welders. Instead of letting the critical projects these welders would complete go undone, robots can do the welding.

Robots completely eliminate any human error from the process while ensuring higher accuracy, waste is lower, and speed increases. Welding robots have a wide range of machinery that allows robotic welding to adapt to many welding processes like arc, resistance, spot, TIG, etc.

1. Arc Welding

Arc process is arguably the most widely-used robotic welding process. In this process, a heat source, hot enough to reach 6,500 degrees Fahrenheit, is created by an electric arc, melting the metal.

The molten metal joins the parts, and once cooled, solidifies into a stable joint (Leidy, 2018). When a project needs a lot of accurate, connected metals, arc welding is a preferred process.

2. Resistance Welding

When an application requires heat treating or has the potential to reduce costs, the process may be accomplished using robots and resistance welding.

With this process, a current of electricity creates a pool of molten metal as it passes through the two metal bases. That molten metal serves to fuse the two pieces of metal.

3. Spot Welding

There are some materials that are not conductive to electric currents, preventing them from being used in other forms of welding. This generally occurs in the automotive industry with the joining of parts of the body of an automobile.

To address this, robotic welders will create a form of resistance welding by joining a pair of thin sheets of metal together at a single location.

4. Tig Welding

Automated welding applications that demand precision may require TIG Welding. The process is also referred to as gas tungsten arc welding (GTAW). An electric arc is passed between the tungsten electrode and the base metal and the heat produced will form a molten puddle.

5. Mig Welding

Gas metal arc welding, often referred to as GMAW or MIG, is a simple, rapid process which uses a high level of deposition.

The process involves a continuous wire feed moving to the heated tip of the welder, which enough heat to melt the wire, creating a large volume of molten metal that drips onto the base for joining to another piece.

6. Laser Welding

If welding projects need accuracy with a high volume of parts, laser welding is the correct method of joining metals. Laser welding is often used to join small parts such as jewelry or medical components.

7. Plasma Welding

Plasma welding provides the most flexibility of all the methods since the operator can adjust the speed of gas going through the nozzle and the heat quickly and easily.

Robotic Welding Applications

Robotic welding, with its efficiency and productivity advantages, has become widely recognized in the heavy industry and metal-bulking industry, and particularly in the auto industry where spot welding and laser welding are prevalent.

Robotic welding is ideal for short welds with curved surfaces and repeatable, predictable movements that do not require constant shifts and changes in the welding process. With the addition of external axes, a robot can also be used for long welds, for example in the shipbuilding industry.

Even though robotic welding is commonly applied against mass production environments, where the priorities are efficiency and number, programs can be tailored for any need, and robotics can be utilized for smaller, and even one-off production runs, with the same cost-effectiveness.

Robotic Vs. Manual Welding

There is still a time and place for manual welding to be seen in today’s manufacturing industry. For projects where you need someone who is an expert and can change, very quickly, the styles of welding used, manual welding is your best option.

A manual welder can quickly change what he’s doing, however, a robot cannot adapt to uncertain situations as quickly.

Since manual welding is still a process many companies require, there is certainly no immediate danger to professional welders disappearing any time soon.

In fact, with the shortage of qualified welders mentioned above, those individuals with certification will easily find jobs, even while multiple companies are implementing robots.

Replacing manual welders with robots will not put AWS out of the certification business. It is important to know here that most operators of robot welding equipment will need to certify in the robotics side of this industry, which AWS certifies.

Having people who are up to date with robotics and also understand welding, is a way to ensure that projects are programmed correctly to be completed as quickly and cost efficiently as possible.

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