Safety is a primary concern when considering robotic industrial automation. Precise, productive, and dependable, robots are valuable industrial workers. But they are strong and fast enough to cause severe to fatal accidents if a worker enters a work area at the wrong time. A robot that is properly installed with well-trained users has all the safety features necessary to keep everyone protected.
In 2013, the Robotic Industries Association updated the safety requirements (ANSI/RIA R15.06-2012) for robots for the first time since 1999. The updates are a major step for manufacturers and users in the United States and are the adopted international standard ISO 10218:2011 Parts 1 and 2.There are millions of robots worldwide, yet the safety record is pretty impressive. As the robotic industry continues to quickly expand, RIA has done an excellent job of being proactive to address safety issues and provide resources to educate robot owners. The Safety Standard gives guidance on proper robot use, the safety features included in robots, and how to properly integrate robots into factories and work areas.
Safety Compliance Awareness
OSHA relies on the standard when looking for compliance with the regulations and has four main requirements integral to ensuring robot safety, especially during programming, maintenance, testing, setup, or adjustment.
1. Lockout/Tagout (LOTO)
LOTO is intended to avoid injuries in the event of an unexpected startup or release of stored energy of equipment, particularly during maintenance. The LOTO necessitates all hazardous energy sources are removed during maintenance activities by either removing the power source (such as plant air or a spring under tension) or unplugging it. Then, the user is required to put a lock and tag on, so the person who can lock and unlock it is identified (tag) and the power cannot be turned on without removing the lock.
Unfortunately, this doesn’t solve all safety problems as sometimes the robot needs to be powered up to program or diagnose. Mike Taubitz, the Senior Advisor for FDR safety LLC said, “I have this unfortunate distinction of having done more than 80 fatality investigations, that doesn’t even count the serious injuries. In almost all cases, these occur during the breakdowns, the nonscheduled, non-routine maintenance tasks. Go tell your mechanic that you don’t want him to have the engine running with the hood open because he might get his fingers caught in moving parts. He’s going to look at you and say, ‘I can’t do my job.’ The engine has to be running to do troubleshooting and diagnostics. In probably 95 percent of all maintenance tasks where there’s been a breakdown, we will need to have power on at some point in time. That’s why we have to rely so heavily on the training, skills, and judgment of people to know when to shut down and do full lockout for control of hazardous energy.”
2. Risk Assessment
The first step towards safety design should include a formal risk assessment. Every potential hazard or environmental influence must be considered. Once hazards are identified, they can be classified by certain criteria such as severity, frequency, and avoidance possibilities.
This assessment should also include the coordination of the maintenance team and programmers so the end user has the knowledge of the machine and the safeguards.
A micro-level risk assessment also involves a Task-based Risk Assessment (TaBRA). This focuses on specific types of tasks required (non-routine and routine) and then outlines the risks associated.
3. Safe Guarding
Safe guarding is a major concern for companies looking to save money and lives. Serious and fatal injuries have happened to mechanics and electricians where the design has failed in providing easy access to get work done safely and quickly without defeating the safe guarding.
Workspaces need to be clearly marked, so each of your workers knows what floor space is out of bounds when the robot is operating.
A thorough understanding of all the safe guarding options and capabilities saves time and money. Safety system designers must be knowledgeable about proper installation and every intricacy of integration. For example, distances must be carefully calculated so safety devices stop hazards before workers reach them.
Some examples of safe guarding:
Protection on the Outside
Protective safety environment begins with the right fencing. There are many different choices for perimeter guarding. Determining which type of guarding to choose depends on the application. Sometimes it is necessary for both hard-guarding and light curtains to be used so they work seamlessly with the work cell.
Hard-Guarding: This variety of guarding includes physical fencing and interlocking safety latches that stop the system when opened. The floors and work areas should also be clearly marked as zones of movement for each robot.
Light Curtains: Light curtains provide more flexibility. These optical perimeter guards trigger robot systems when their light is interrupted.
Adequate Clearance: Ensures enough clearance around all moving parts of the system and allows for a remote "diagnostic" as much as possible. When necessary, enact a "buddy system" when a worker has to enter.
Illumination: Lighting is important to the workers to maintain visual references and to read and see written instructions, buttons, levers, etc.
Protection on the Inside
Internal protection is often necessary in a work cell such as motion sensing safety scanners, light curtains, or floor sensors can stop the robot whenever a worker crosses the barrier.
2D Vision: Detects movement and coordinates part position so the robot can adapt its actions.
3D Vision: Contains cameras or laser scanners at different angles for a more precise analysis and object detection than 2D.
Ventilation Systems: To remove harmful fumes and gases
Collision Detection Sensor: If a pressure or abnormal force is sensed on a surface, an emergency signal is sent to halt the robot motions.
Safety Sensors: These can take the shape of a camera or a laser, but they both are made to inform the robot there is a presence nearby. This could then trigger the robot to slow down or stop completely when a worker gets too close. There are numerous safety products available such as the Pilz SafetyEYE® system, the S3000 Expert Safety Laser Scanner, and the Omron area scanner.
Training is imperative for every specific robot (and their programmers, operators, and maintainers) to ensure the safety of all people and robots. It is important to know the safe operating procedures and when to apply LOTO. A well-trained worker should know when and how to intervene safely and if a machine stops due to a fault or due to normal operation. Consistent refresher courses made available to the workers are also important to help re-iterate the importance of safety and to discuss the always advancing technological developments. The integrator should help train and reinforce safety procedures for the robot end user. At RobotWorx, we start you off right and offer free training with the purchase of our reconditioned robots. After a training course, workers should be familiar with the full range of motion, known hazards, robot programming, location of emergency stop buttons, and safety barriers.
Finally, be sure to constantly supervise your workers and remind them of safety as it is easy for them to become complacent or over confident to the hazards that come with complex automation.
Designing Safety Solutions with RobotWorx
The extent to which safety standards are followed varies with each company. Robot manufacturers and integrators adhere to certain safety standards when creating work cells, but many companies create an additional safety environment around each cell to include safety relays, curtains, and mats.
Robots are costly investments; it is in the best interest of every company to protect equipment as well as workers. The engineering experts at RobotWorx understand the importance of safety preparation and will work alongside each customer to determine the best safety solution. Worker safety is paramount to our team and we are ready to help train your team after your purchase. RobotWorx professionals are ready to help customize the perfect safety environment for you. Contact us online or call 740-251-4312 for more information.