Now's the time to AUTOMATE

Labor shortage, safety concerns, economic slowdown make robotics a consideration

PRACTICAL WELDING TODAY® MAY/JUNE 2002

May 30, 2002

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This article outlines some of the challenges fabricators are facing and how robotics and automation equipmentmakers are trying to address these challenges. Also addressed are different equipment and technological advancements and other factors affecting welding automation.

Robotic welding systems

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If you looked at metal fabricators' and manufacturers' wish lists, you might see a lot of similarities among them, but you'd also see something the manufacturing industry has in common with all other industries: the need to do more with less.

Here's what fabricators are saying: They must increase their output with fewer welders, because the skilled welder pool is small. They want to reduce costs, sometimes by buying only what they need now, so capital equipment investments are down. More price-conscious buyers are pushing for lower prices on the materials they need to fabricate their own products.

"Many fabricators compete at a level where profit margins are at their lowest while demands for quality are unapproachable with manual operations," said Mike Sharpe, engineering manager for the Materials Joining Group at FANUC Robotics North America Inc., Rochester Hills, Mich. (www.fanucrobotics.com). FANUC Robotics specializes in robotic systems for a variety of applications, including arc and spot welding, laser cutting and welding, machine tending, material removal, and palletizing.

"Because of these issues, fabricators are forced to really understand the value of their capital equipment purchases. Installation cost, floor space, time to install, and utilities all add up to what were termed not too long ago as intangible costs," Sharpe added. "They must also realize that production volume, part mix, and robotic welding system utilization must be optimized to gain the most from their capital equipment expense."

Because so few skilled welders are available, training is another concern, both in expense and the challenges of manual and semimanual welding.

For these reasons, robotics has become an advantage, according to Tim Nacey, general manager, Industrial Division, Panasonic Factory Automation, Franklin Park, Ill. (www.panasonicfa.com). Panasonic specializes in arc welding robotic technologies and manufactures robots, pre-engineered workcells, and welding power sources used by Tier 1 automotive manufacturers and their subcontractors, off-road and heavy equipment builders, trailers, general metal fabrication, and smaller job shops.

"Even though the economy has slowed down, and it is a bit easier to keep welders on staff, there is still difficulty associated with hiring new welders," Nacey said. "Clearly, there is a shortage of skilled workers. Managing with fewer people is one of the key reasons robotics has become such a growing industry."

And through using robotic welding systems, training expenses decrease, Sharpe said.

"The reduced cost of training with today's automation allows even more fabricators to consider a robotic welding system," Sharpe said. "Ease of programming and maintenance also reduces the skill required to perform these functions. Requirements for experienced programming and maintenance personnel are reduced."

Chris Anderson, market segment manager for welding at Motoman Inc., West Carrollton, Ohio (www.motoman.com), said he has noticed an increasing number of tradeshow attendees inquiring about robots because they can't find skilled welders to hire. Motoman provides complete robotic systems for applications such as arc welding, assembly, coding, dispensing, material cutting, material handling, material removal, and spot welding.

"Robots continue to be fairly easy to program, with languages geared to floor personnel versus computer programmers," he said. "Teach pendants have larger displays and often use graphical user interfaces. The proliferation of PCs has also helped shop floor personnel be less intimidated by technology."

Reduce Cost, Increase Information Flow

Equipmentmakers are dealing with three major goals in providing robotic welding systems:

  1. Low cost
  2. Software programming packages that require limited welding knowledge
  3. Limited robot downtime through offline programming

"Arc welding robots and robotic workcell prices continue to drop. At the same time, robots have increased speed and improved repeatability. We have introduced technology from other parts of the world, like AC GMAW power supplies that help increase weld process speeds and reduce rework," Anderson said.

Another major cost of welding is labor, a cost that robotics can help decrease.

"Now less expensive than ever before, a robotic system is still about three times more productive than a manual welder," Nacey said. "In addition to considering the cost of labor, some equipmentmakers have acted on the need for improved quality by adding Internet access and arc data monitors to the robotic workcell. These monitors are designed for fast data collection and information processing, which is used to compare actual welding conditions to ideal."

"Previously these [arc data] monitors were boxes that flashed and saved reams of data to disk," Anderson said. "Motoman has been combining monitors with PC-based software that displays a picture of the part with weld locations highlighted. As the part is welded, the picture is updated with green, yellow, or red icons at each weld location based on whether parameters were within limits on the arc data monitor.

"The result is a closed-loop inspection system where the monitor is indicating visually to the operator which welds are suspect or out of limits. The operator inspects the welds to determine if the weld is acceptable or nonconforming."

Sharpe agreed.

"Users realize that in today's world they need quick and accurate information, whether it be for production control, quality management process statistics, or maintenance and diagnostics information," he said.

According to equipmentmakers, automated welding tools and technology are evolving to help meet fabricators' needs. Web-based software programs allow service personnel to access the robotic controllers for diagnostics and troubleshooting. Increased computing power makes it possible for a robot controller to handle multiple arms. Robots continue to evolve with higher performance and fewer, smaller parts.Robotic Industries Association (RIA, www.robotics.org) compliance also is causing equipmentmakers to make design changes in robotic welding systems. Safety specifications have solved some ergonomics issues, such as teach pendant weight and design. Not only are they lighter, but some also use a Windows® interface and an Internet connection, making them easier for first-time users to operate.

"The robot [and] welder truly act as one, mimicking an experienced skilled welder at the job," Sharpe said. "Any user with visual acuity and the ability to enter data on the teach pendant can develop real working and productive weld programs. After the user enters the process and part parameters--material type, joint configuration, wire size, shielding gas—the robot selects the most suitable weld procedure."

Offline programming with virtual welding process simulation is another advancement in robotic welding, aiding in workcell design, programming, and development, Sharpe added.

"Forethought saves a considerable amount of time and money as all facets of the welding robot workcell are kept in mind," he said.

Other progress includes integrating servo controls in the weld process to couple the welding arc with the robot motion. Applying servomotors instead of a standard wire feed motor can offer compactness and higher torque. The servo wire feed then can enable the robot to react more quickly to changing weld conditions. A servo wire feed motor also can be used for sensing and can more accurately monitor torque.

Working With New TechnologyWhile equipmentmakers focus on upgrading systems, end users are evaluating price--in addition to the new technology these systems employ. While most equipmentmakers have had positive responses, cost plays a large role for fabricators today.

ABB Inc., Collins, Colo. (www.abb.com/us), for instance, has created offline programming software that simulates exactly the entire welding cell, allowing welders to program parts, conduct time studies, and process improvements without taking the robot out of production. ABB specializes in power and automation technologies.

Also, some of its software allows service personnel to access robot controllers to determine robot status and performance for the day, for example.

"Users who have purchased programming with their systems have been able to be up and running within days of receiving their system," said Chuck Boyer, marketing services manager for ABB Inc.

Panasonic's Windows CE® teach pendant is another example of new technology. It's new because it uses an icon-based teaching system, much like any Windows-based program run on a PC. Nacey said the teach pendant has been well-received by customers.

"By using a teach pendant with an optional programming package, training and programming are carried out offline to free the robot for productive welding, a major economic benefit," Nacey said. "In addition, greatly enhanced learning efficiency has been the result of using icons and Windows' familiar functionality. For example, the operator can name points on a weld in recognizable, understood words. 'P1,' for instance, becomes 'left lower corner.'

Anderson noted that Motoman has introduced AC GMAW power supplies that can produce a larger weld with less heat input, resulting in better gap-filling ability and higher travel speeds on thin-gauge material. Reactions to this new technology have been varied, he said.

"They had a very poor reception initially due to an $8,000 premium price over a low-end constant-voltage machine. However, we have had cases where these welders reduced rework 87 percent or welded exhaust material at 120 inches per minute," Anderson said. "Now customers are realizing that the extra $8,000 spent on the power supply is making their $200,000 robot cell more productive, and the return on investment becomes fairly easy."

Many trends in automation are leading equipmentmakers to incorporate new technology in their robotic welding systems, including diagnostics, programming, and integrated process control limits.

"Diagnostics are important for keeping the machine up and running while monitoring the process," Boyer said. "There are signs that diagnostics can look for to inform service if a problem is developing so that a quick service or maintenance step can prevent or eliminate a larger problem from developing. Preventive maintenance can be scheduled as diagnostics track the cycles and arc-on time to determine how to get the most out of consumable parts while avoiding failures."

Nacey said that he's seeing a trend toward small robots in general. One reason is that more shops are adding welding to offer more to their customers. Some of these shops didn't weld in the past, so it's been easier to introduce automated, rather than manual, welding. Along the same lines, small robots can be easier to use and more economical.

"The 4- and 6-kg [robots] comprise a larger percentage of total sales than in the past," Nacey said. "[This is] a trend we have seen when working with subcontractors to Tier 1 automotive manufacturers."

The Future of Welding Automation

These equipmentmakers think computers will be a growing force in welding automation, from PCs to integrated welders and robots to high-performance communications.

"Robots are pieces of a larger manufacturing picture," Anderson said. "Manufacturers are looking at networking equipment in the factory in an effort to monitor productivity and improve information flow. Some manufacturers are asking to network the robots in order to automatically download programs or view production status. This will continue as a trend as hardware costs continue to decrease and more PC software programs are developed."



Stephanie Vaughan

Contributing Writer

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