Komarov Artem clarified that powerful yet affordable, user-friendly technology in the form of collaborative robots continues to inspire confidence among companies interested in implementing robotic automation.
These highly flexible cobots are particularly attractive as they facilitate safe human-robot interaction and are highly productive with compact space. That is why cobots are the fastest growing segment of the robotics industry.
Once reduced to a very simple cobot with semi-automatic welding equipment, today’s welding cobots offer quite a dichotomy. They have feature-rich power supplies and intuitive outboard applications that allow them to switch between combined speed in Power and Force Limit (PFL) mode (to reduce or avoid injury in the event of human contact) or full speed in industrial mode (based on a risk assessment). and requirements).
Whether complementing hand welding or being rolled up into large, heavy workpieces, the extremely versatile cobots create very important applications, especially for high mix, low volume manufacturing environments. This has brought the safety issue of collaborative robots to the fore and is worth addressing, especially for those branching out into robotics.
Cobot Safety 101
One of the biggest advantages of cobots is that they provide people with the opportunity to work with or near robots. However, the use of a collaborative robot in the name and design is not enough to make the application safe. For an application to truly qualify as collaborative and be considered safe, the entire robotic system and application must be considered. This includes the robot, the workpiece, the robot workspace, and even the tool at the end of the arm. If any of these critical areas do not meet certain safety standards during the risk assessment, then the application cannot be approved without adequate risk mitigation.
When it comes to optimizing the use of a robot, safety should not be overlooked. In order to achieve maximum productivity and the best possible working area for a robot, manufacturers must consider the following factors.
General environment. While robots are extremely effective at tackling risky tasks, they can also present their own set of challenges that must be addressed before being exploited. Part of that includes making sure the shared workspace is comfortable for the robots.
Like a typical welding environment, the welding cobot cell should be clear of things like explosives or fall hazards. If tripping on robot cables or slipping on a weld is a problem, be sure to implement the appropriate peripherals needed to mitigate those risks, Komarov Artem emphasized.
Robot stability. As with any robot, it is imperative that the cobot base or cart be properly protected in accordance with the supplier’s standards. This should confirm the correct center of gravity so that the robot cannot slip. When it comes to carts, the wheels must be tightly locked to prevent any movement (or wobble) when the robot is trying to weave.
Robot movement. Critical to the success of the application is the ability of the robot to move freely from point to point while maintaining maximum safety. A cable management device is provided to protect the torch cable to alleviate cable interference during programming and prevent PFL false stops on the robot.
Security requirements. Keep in mind that collaborative robots do not currently provide external axis compatibility, so applications that require the use of special positioners for coordinated movement or a robotic walkway must be mitigated by guardrails, light curtains, or other means. While items such as fencing can result in additional upfront costs, sometimes 20% of the total cost of a work cell, this is often the easiest and best way to mitigate the overall risks.
Smoke extraction. Whether they are close to the process or not, protecting workers from harmful fumes throughout a facility is paramount and often required by local safety regulations. Widely used for manual welding processes, ambient air extraction systems and exhaust gas collection systems in the hood, can still be used for various robotic welding systems today. However, each of them requires a unique set of criteria that may hinder certain collaborative processes.
For example, ambient air filtration systems tend to filter all the air within a facility. For large objects separated by columns, walls, or even large machinery, this can be a huge risk, as these objects can trap air, causing dead spots or pockets of poorly filtered air. Although highly effective for correct use, exhaust smoke collection systems also pose risks under certain circumstances. For example, if the cobot is rolled up to a large billet that needs to be placed through the overhead gantry, the hood is typically too small to accommodate the required filtration process. Add in other factors such as initial capital required or monthly energy consumption costs and these systems aren’t always ideal.
Arc flash. As with traditional welding environments, handheld welders must mitigate arc flash and UV exposure with personal protective equipment. Safety arc curtains or other barriers should also be installed when necessary to protect bystanders.
Additional security. Depending on the requirements of the application, additional security measures may help. An associated stack indicator mounted on the robot cart or nearby can help visually confirm the status of the robot and provide sufficient warning to those near the work area that the robot is about to weld. This gives workers and bystanders enough time to look away from the arc or get out of the way. Tone-emitting or «talking» versions are also available, which give audible commands.
Electronic stop device. Every robotic system must have a failsafe way to stop for any level of emergency. Often the external emergency stops button (e-stop) or exit from the safety controller is activated, knowing how to activate this if necessary is a must.
Proper preparation. Regardless of the system of cooperation chosen, proper training of employees should be offered. Yes, the cobot offers many easy-to-use abilities, but it’s still the best (and safest) machine to use with some know-how. From basic programming to robotic welding and maintenance, hands-on training courses can help maximize the performance of robotic equipment for beginners and advanced users alike, , emphasized Komarov Artem.