Forward from The FABRICATOR

By Tim Paton

 How results, advancements, and ease of use made cobots popular

Collaborative robot welding packages are a viable solution for small and medium-sized job shops. They are easy to implement and operate without prior robotic experience and require a lower overall investment. Lincoln Electric

The demand for robotic welding systems on small to medium-sized shop floors grows steadily, reflecting the urgency of job shops to make their operations more efficient and competitive in the face of the notoriously tight market for manual welders.

This is a relatively new phenomenon. Up until recently, the uptake of robotic welding had been more prevalent in heavy industries. The prevailing perceptions that robots are costly, inflexible, and difficult to program have deterred small-scale companies from investing in the technology.

Another principal area of concern has been safety. Like any other piece of machinery, an industrial robot typically operates in an environment safeguarded by barriers, screens, and other protective measures to shield human workers from the risk of injury. Smaller enterprises have been concerned that even modest-scale robotic systems bring similar risks, and that the costs to maintain a safe workplace will be unsustainable.

These previously valid perceptions are gradually being swept away by the emergence of collaborative robotic welding systems. Collaborative robots—often referred to as cobots—are specifically designed to work more closely alongside humans than standard robots, with a level of flexibility and affordability that make them accessible to a wider range of fabricators.

The Ideal Cobot Welding Job Shop

The job shop that can most benefit from collaborative robotic welding is a first-time or recent adopter of automation that has found its production demands have surpassed the output of its existing capabilities. Its welding output is more in the high-mix, low-volume, batch-job range, and this type of shop typically has at least one experienced welder or welding process associate on staff. Though the available payload and arm reach of some collaborative robots has increased to 12 kg and 1300 mm, respectively, cobot welding is best for companies that handle small, less complex parts that don’t require a positioner.

Those with a need for flexibility also can benefit from using cobots—the smaller, lighter, and more portable cobots are easy to install and can move freely around a factory whenever and wherever they’re needed. The inherent safety features also allow them to be deployed without the extensive fencing and guarding required for traditional industrial robots.

Improved Quality and Productivity at a Lower Investment

One of the major benefits fabricators find appealing about collaborative robotic welding is the lower all-in investment compared to traditional robotic welding cells. Not only does a cobot typically cost less than a heavy-duty 6-axis robot, the elimination of safeguarding equipment, positioners, and space allocation renovations provide additional savings. The ability to install and operate cobot systems without hiring additional staff likely will impact labor expenses as well.

Smaller shops that rely on one or two manual welders, who are often stressed and fatigued, find that the addition of welding cobots is well received. Repetitive, monotonous, and time-consuming welds can be handled by the cobot, freeing up manual welders to focus on more custom, complex, and stimulating work.

Cobots have the ability to detect external forces and stop safely when making contact with a person or object, allowing man and machine to work simultaneously on different aspects of a welding application, significantly increasing welding throughput and overall process productivity.

Collaborative robots can significantly improve weld quality by providing precise, continuous, and steady weld motion for smoother, stronger seams. They also improve quality by producing longer welds without the need for multiple stops and starts common with manual welding.

Easy programming methods allow users to tack and weld parts by physically moving the robot arm through the desired weld paths, essentially teaching the cobot the necessary weld motion, which it can then replicate with the push of a button. ABB Robotics

Simplified Installation and Programming

Perhaps the most distinguishing feature of a welding cobot is the intuitive human-machine interfaces and programming methods that enable people with little or no previous robotic experience to successfully deploy and program robots.

One of the easiest programming methods is “lead-through programming,” where users can tack and weld small parts by physically moving the robot arm through the desired weld paths, essentially teaching the cobot the necessary weld motion, which it can then replicate with the push of a button.

Another method available with several leading robotic OEMs utilizes a tablet interface that programs a weldment through a graphical interface with interlocking drag-and-drop blocks. A user can see the program develop as they drag and drop the blocks on the tablet, making any necessary adjustments along the way.

For those more experienced with robots, the option still exists to use standard programming language for higher-level welding applications.

Advanced Cobot Welding Packages

Companies have introduced collaborative robot packages that balance the goal of simplified programming with the ability to offer advanced application capabilities.

Existing cobot arc welding packages have taken lead-through programming to the next level. For instance, ABB Robotics' GoFa cobot has an Easy Teach device installed between the robot flange and the welding torch bracket. It is equipped with two buttons that operators use to teach the welding path positions and a ring nut to scroll through various programming instructions. The selected instruction is shown to the operator on mounted screens, ensuring full usability from every angle. This enables high-quality welds on more complex parts while maintaining the requisite programming simplicity.

Some packages include proprietary programming software with built-in welding libraries that are compatible with tablet computers. A user simply inputs the material type and material thickness and the user moves the robot to the beginning and end of the weld. The welding parameters and travel speed of the robot are then set, and the robot is ready to weld at the push of a button.

A Final Analysis

The advantages job shops have in adopting collaborative robotic welding are many, providing highly user-friendly and economical means to keep up with production demand, increase weld quality, and provide relief and support to their valuable manual welders.

Nonetheless, it is suggested that welding operators still take reasonable safety measures when working with collaborative robots, such as by wearing protective gear when close to a live arc. Flash curtains are mandatory to protect people from the brightness of the welding arc, and fume extraction also is needed for some applications.