Using a robot welding system or an automated manufactur ing cel l doesn’t mean that a shop eliminates the need to be concerned over safety for welders.

While automation and robotic systems take some of the manual labor out of the production flow, shops can’t get completely away from having to perform some manual processes.

David Hough, an analyst with PSC Group (www.psclistens.com) said even though best-inclass companies are automating their welding processes, 60 percent to 80 percent of those companies still perform manual processes along with automation.

“It’s difficult to stay out of manual processes completely,” Hough said. The manual processes can be loading and unloading the workpiece to and from the positioner, or manually carrying work pieces to a secondary operation in another part of the shop. In these and many other operations, workers continue to be very necessary for most welding operations.

Marcos Aranha, project manager for Ohio Valley Automation, a welding cell systems integrator, (www.ohiovalleyautomation), said safety components are integral to automated welding systems.

“Everything has to conform to the ANSI/RIA (Robotics Industry Association) R15.06-1999.

“Apart from the automation integration process itself, the next biggest consideration is safety,” Aranha said.

As an automated welding cell integrator, Ohio Valley Automation analyzes each system it works on to ensure the operator is protected from arc flash, pinching points, and other parts of the system.

However, Aranha said that all the safety precautions in the world can’t stop an operator from doing something unsafe in the operation.

“I’m always amazed at how some operators will try to defeat our safety systems, and it’s our job to stay one step ahead of them. In the past, when most manufacturing operations were manual, and the systems were more open, safety standards were different than today.

“As factory automation got more prolific, a transition occurred, and we began seeing more moving components outside the control of humans. Often, operators try to override these safety controls to try to solve a machine problem manually, putting themselves at risk,” Aranha said.

Mike Sharpe, director of engineering for the Materials Joining Group at Fanuc Robotics (www.fanucrobotics.com), said when putting a robot into a work cell that uses positioning devices, safety is a big concern.

Fanuc offers what it terms a “dual check safety” safety system – a “category four” system – that Sharpe said is the safest. The safety system has an operator interface through a local stop unit that interrupts all energy to operator loading and unloading of parts from the weld positioner.

To discourage operators from overriding the safety systems, Aranha said Ohio Valley Automation takes into consideration the ease of use when integrating automated welding systems.

“If we design something that makes the operators go back and forth, use lots of physical motion and make their job more difficult, it’s more likely they’ll try to defeat the system; they’ll try to find shortcuts,” Aranha said.

“As an integrator we make our recommendations, try to design user-friendly systems, and put the required safety systems in place, such as a dual channel emergency stop. Then it’s up to the customer whether they will take our advice and ensure safe use of our systems,” he added.

However, he noted that his company’s customers are cracking down on safety.

“When talking about robotics, we have to implement redundancy. That means that one component failure can’t impede the system from shutting down if the emergency stop is activated, which is one of the items defined by the ANSI/RIA R15.06 standard. We provide a full risk assessment and recommend the safety systems required to keep the automation cell up to code,” Aranha said.

There are a number of things to consider when doing a risk assessment on an automated welding cell, and there are basic safety requirements that must be implemented – the customer has no choice about compliance, he explained. However, there are other safety systems that are optional, such as implementing a “laser light guard” around the cell that will shut the system down if someone passes through the light versus a physical fence barrier to keep people out of an unsafe area.

“There are ways to open up the cell a bit more and still keep it safe, but ultimately, it’s the customer’s responsibility to accept or reject the optional recommendations. If they reject some of the recommendations, then we have the paperwork to show that the customer rejected our safety recommendations,” Aranha said.