Manufacturing better machine safety
Manufacturing processes and operational intelligence benefit from the rapid advances in technology, as does safety. Historically, the most common way to safeguard workers in and around manufacturing equipment was to provide physical barriers between workers and operating equipment. While this type of safety system results in a safe operation and meets the appropriate codes, it limits productivity and may require significant maintenance. Today, technologies exist that do not require physical barriers, yet they provide the same—if not better—level of safety.
Assessing, monitoring safety risks
Modern safety technology presents the opportunity for significant productivity gains without sacrificing reliability. It is a matter of opening up the processing line and providing better access and equipment visibility. Light curtains, laser scanners, and area (3-D) scanners can be integrated with existing equipment. Additionally, certain equipment, like collaborative robots, includes safety that is already integrated.
So, how do you get started? Perform a safety assessment. Begin by auditing existing processing lines to determine the risks that are present and identify measures in place to protect personnel from those risks.
As part of the assessment, assign every operation in the plant a risk category, which accounts for the potential severity of injury and the likelihood of occurrence, as well as other factors. This will dictate the level of protection required around that operation. Highlight any existing deficiencies. Your immediate focus should be to address these deficiencies as quickly as possible, as these represent a potential liability for a company.
Next, identify risk sources, estimate the risk, evaluate it, and determine whether it is acceptable or needs to be mitigated. A risk tree can help rate each of these parameters: severity of injury, frequency of exposure to hazard, and the possibility of avoiding a hazard. This is a disciplined framework for managing people and machines, and having such a framework is critical for safety. Ultimately, safety starts with design and engineering and continues through operations and management.
Robotic safety has improved significantly. Together 3-D vision and industrial computers create the ability to perform real-time collision avoidance calculations for robots, vehicles, cranes, or lifts in the work environment. Improvements in optics and software, combined with a new safety culture, will continue to drive the proliferation of robots into new industries that will benefit from the flexibility, safety, and collaboration they bring to the job.
Future of safety, robotics
In the future, larger and faster robots will operate safely in collaboration with laborers. By taking input from vision systems, such as a 3-D laser scanner or light imaging, detection, and ranging (LIDAR), and running code in the background, collisions will become a historical occurrence. Personnel will be able to walk into a work cell without performing lockout/tag procedures or forcing the robot to come to a complete stop. Instead, the robot may slow down or alter its path based on sensor and software feedback. This dynamic collision avoidance environment will reduce overall downtime while ensuring the safety of the product, the machinery, and humans. [Automation trade shows have featured such demonstrations in recent years.] As technology improves, so will safety.
Often, when people talk about robot collaboration, they focus on the robotics and ignore how the robot functions in its environment and with people. There are four types of collaborative operation:
- Safety-rated monitored stop allows the operator to interact with the robot when it is stopped, and operation automatically resumes when the person leaves the collaborative workspace.
- Hand-guiding operation allows the operator to have direct contact with the robot, using hand controls.
- Speed and separation monitoring defines different safety zones, so the robot’s speed changes depending on the zone. A protective stop is issued when an operator is in potential contact.
- Power and force limiting occurs when incidental contact between a robot and a person will not result in harm.
Speed and separation monitoring enable the robot to sense the presence of an operator and adjust its speed. Often, this applies to uncaged robots that use safety sensors. Concept Systems has created work cells using lasers or a vision system that predicts a collision before it happens.
This approach allows the robot to continue to function while operators are near because the robot works at specific speeds determined by preset safety zones. When an operator comes too close, the robot will stop. Such dynamic collision avoidance underscores the ability of the robot to react to changes in its environment and increases flexibility and utility.
It is always critical that the robot not collide with a large part or piece of machinery. A recent project achieves this by using speed and separation monitoring. An operator can observe the robot’s movement at a human-machine interface (HMI). When the robot is operating safely, it appears in green on the screen.
When it enters a warning zone, the color changes to yellow, and the robot slows down. If the robot enters a collision zone, it turns red and stops operating.
With the increasing capabilities and complexities of technology, putting a priority on industrial safety is increasingly important. Systems integrators can discover unsafe situations and help companies mitigate risks. Risk assessment and corrective actions have proven to produce a significant return on investment by avoiding unnecessary collisions.
Safety is one of the hidden gems of the technology boom by providing greater safety reliability, increased productivity, and, most importantly, a proactive way to minimize unplanned costs stemming from unsafe operations and resulting injuries.
Michael Lindley is the vice president of business development and marketing at Concept Systems Inc. Concept Systems is a 2016 Systems Integrator of the Year. Edited by Emily Guenther, associate content manager, CFE Media, Control Engineering, email@example.com.
- Assessing safety risks in a facility
- The importance of prioritizing industrial safety
- Advancements in safety technology.
How will the complexities of new technology change safety procedures and assessments?