How safe is your robotic workcell?

Metal fabricators both large and small rely on robots to perform a number of jobs. Whether it be for material handling, assembly, painting, high-volume parts production in large shops, or performing mundane welds to free welders for more complex craft work in small to medium-sized shops, robots have carved a niche in the modern metal fabricating environment and appear to be here to stay.

According to the Robotic Industries Association (RIA), the North American robotics market broke records for orders and shipments in 2016. And a study published by the Boston Consulting Group in 2015 stated that by 2025, the share of tasks performed by robots will rise from a global average of 10 percent to roughly 25 percent across all manufacturing industries.

While industrial robots provide a great many benefits, they also pose a unique set of safety challenges.

As robots continue to find homes in shops of all types and sizes, companies need to ensure these pieces of equipment are integrated properly and that they are adequately safeguarded. Incorporating a combination of safeguarding equipment, such as perimeter guards, light curtains, pressure-sensitive safety mats, and laser scanners, is an essential piece of the puzzle, but it’s not the be-all and end-all in safe operation.

According to the Occupational Health and Safety Administration (OSHA), many robot accidents occur during nonroutine operating conditions, such as maintenance, programming, setup, or adjustments. More often than not, these accidents, which can result in injury or death, are preventable.

Assessing Risk Factors

Safeguarding equipment is not a one-size-fits-all solution, said Matt Brenner, vice president of sales at Rockford Systems LLC, Rockford, Ill. What you use and how you use it depend on the task the robot is performing.

“Two robots with consecutive serial numbers that are being used in the same plant are used differently and quite possibly must be safeguarded differently based on how they are used,” Brenner said.

As a 13-year veteran at Rockford Systems LLC, an industrial machine safeguarding equipment manufacturer and systems integrator, Brenner has seen the good, the bad, and the ugly. From Brenner’s perspective, there is no reason not to properly safeguard a robot. The first step in finding the right combination of safeguarding equipment for the robot is conducting a thorough risk assessment or machine survey.

“We survey the machine mechanically and electrically to understand what it is and how it works. And then we interact with the operators of that machine to understand how they interface with it and what their manufacturing process looks like. From there we design a system with their input,” Brenner explained.

The best way to safeguard your equipment, he added, is to observe the machine while it operates, evaluate all of the variables around it, and then use that feedback to design a system unique to that robotic cell. Some fabricators opt to have their robots safeguarded before they arrive on the shop floor. That’s a great idea in theory, but there are risks.

“It’s very difficult to look at a 3-D drawing on a computer screen and take into account all of the different variables of the plant. So they install the robot, and if they modify anything at all, like the position of a control panel or something they didn’t anticipate when they were looking at a 3-D model, there’s a chance it falls short of being fully compliant,” Brenner said.

Make Sure Operators Are Trained

Todd Griffieth, general manager-technical operations at OTC Daihen Inc., in Tipp City, Ohio, knows the value that a robot can have in a shop environment. The company manufactures robot arms, power sources, wire feeders, and torches for robotic arc welding applications. He also knows that robots are not intuitive beings, but machines that do what they are programmed to do.

“People have this perception that robots are these autonomous, intelligent pieces of equipment that are cognizant of what’s around them. A typical robot is a simple, repetitive machine that does the same thing over and over again, regardless of what’s occurring, until you tell it to do something else,” Griffieth said.

Ensuring that robotic system operators are properly trained seems like a no-brainer; however, Griffieth said it’s an initiative that companies unintentionally allow to fall through the cracks. There are a couple of reasons for this.

The first reason is staff turnover. When that trained operator leaves, it can be tempting for a company to slide in a replacement operator to simply mimic what the trained operator did.

“They’ve got a routine down. What they don’t realize is they’ve taken a very complex piece of integrated equipment and simplified it to the push of a button without really understanding how it works.

“Forgetting to revisit safety training is one of the biggest end-user failure points I’ve seen,” Griffieth added.

Another reason is lost production time. Many companies do not have a dedicated training robot, and most are not willing to take their production robots offline for training purposes. This often means that new operators cut their teeth on a live production robot without fully understanding the machine’s capabilities. On a related note, ensuring that robots are maintained and working properly is a must.

“Shortcuts seem to occur when equipment is not properly maintained. Things start breaking, and then you start bypassing certain things. The more that happens, the more operators are put at risk to potentially harmful situations,” Griffieth noted.

Consider the “What Ifs”

A common mistake many companies make is they only think about safeguarding the robot’s work envelope, said Carrie Halle, vice president of marketing at Rockford Systems. They fail to look beyond and think in terms of “what if.”

“What if there’s a software malfunction or something totally unexpected happens that causes the robot to stop doing its normal task? What if instead of its normal task the robot fully extends its arm in a different direction, unexpectedly throws an object it is handling, or suddenly moves at high speeds?

Best practice is to plan for the unexpected. Those are some things you have to look at after it’s installed and in place,” Halle said.

Even if a robot is programmed to perform a specific task, it is capable of reaching higher, farther, and with enough force to cause injury or death.

“A robot relies on a control to tell it what to do. Well, we all know that computers have problems, so you have to consider how severe that problem could be. And that’s part of the RIA standard. You have to design [a safeguarding system] around the worst-case scenario,” Brenner added.

Create, Adhere to Safety Procedures

Have well-written and robust operating procedures, maintenance procedures, and setup procedures, Brenner said. Known as administrative controls, these written procedures are designed to make sure everyone knows how to interact safely with the robot.

Brenner said, “Every circumstance is different. If you safeguard these properly, then I think you can interact with these machines in a much safer way. You are definitely reducing risks and exposure that way.

“For example, if I’m going into a robotic cell that does not require me to lock the machine out, I’m either opening a door or I’m walking through a presence-sensing device, like an infrared laser, to get there, so I’ve already sent a stop signal to the machine. If I’m standing inside of that workcell, oftentimes you’ll have a secondary device, like a laser scanner, that sweeps the floor and is also detecting my presence. So I’ve crossed two safeguarding devices before I’ve even touched the robot. So safeguarding the robot properly helps with interaction.”

Along with having written procedures, there have to be consequences for removing necessary safety equipment or when procedures are not followed.

“We know of a local aerospace manufacturer and one of their cardinal violations is the removal of safety equipment. If an employee removes safety equipment from a machine, they are fired immediately. They are really good about that, but some aren’t. Certainly there are consequences for not following OSHA regulations in the form of fines and citations,” Brenner added.

Know the Real Cost

If you think it’s expensive to implement the right safeguarding equipment, train your staff, maintain your robot, and create policies to ensure your safeguarding practices are followed, consider how much it will cost you if you don’t do those things, said Halle.

Accidents that result in injury or death pose two types of costs, direct and indirect. Direct costs, Halle explained, are things like the OSHA citation or fine, medical bills, lost productivity, or even paying staff overtime to make up for lost productivity.

But indirect costs can wind up costing a company anywhere between four and 10 times more than direct costs. Indirect costs include legal fees, productivity declines due to low employee morale, changes to the production process, and hiring and training replacement personnel. They also include allocating investments once targeted for growth to cover the cost of the accident, higher insurance rates, lost coverage altogether, and lost customers as a result of the accident.

“What will it cost you if your brand becomes known as this unsafe or uncaring brand? What if your company comes under negative media fire? It’s this downhill snowball effect, and sometimes people just consider the cost of the citation,” Halle said

Helpful Resources

If you aren’t sure where to begin with robotics safeguarding, here are a few places to start:

• OSHA 1910.212, Machinery and Machine Guarding
• ANSI/RIA R15.06-2012, Robot and Robot System Safety
• Visit the RIA website at www.robotics.org to search for industry events, training opportunities, and informational webinars.

OTC Daihen Inc., 888-782-7626, www.daihen-usa.com

Rockford Systems, 800-922-7533, www.rockfordsystems.com