Welding Automation: Innovations Continue To Evolve

May/June, 2011

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With its ability to increase productivity without raising labor costs, welding automation can significantly help fabricators.

To further enhance this productivity, many companies work to produce new innovations or to improve existing products as Koike Aronson Inc., Lincoln Electric and Miller Electric have done.

Koike has created several new systems to help its customers increase productivity – an anti-drift system, a low-cost programmable positioner controller and a lightweight girth welder.

For the first new system, Koike saw that in some welding applications where the vessel is on turning rolls, the vessel itself has a tendency to walk. The vessel being welded will shift while on the turning rolls, causing its centerline to drift from its original position.

“In welding applications where you’re doing several passes, [this walking of the vessel and shifting of the centerline] is real bad for the welder, because you need to keep stopping and readjusting,” says Don Burgart, Koike’s product manager.

As this would decrease productivity, Koike designed a system to prevent walking of the vessel. Burgart points out that though anti-drift systems have been on the market for a while, the Koike-designed system adds new innovation.

“[What the] old systems always did was move the vessel, either raising it up or down, or moving it left and right,” explains Burgart. “With our system, the centerline of the vessel always stays in the same point, so no additional adjustments have to be made.”

To keep the centerline in one place, the idler roll of the anti-drift system makes use of what Burgart calls steerable wheels. These wheels pivot, moving right or left, so if the sensor on one end of the vessel senses any movement, the system will steer the wheels to prevent walking.

Burgart explains that when the system steers the wheels, it’s essentially aligning the rollers, which compensates for any misalignment that might have occurred during setup of the vessel.

Other systems in the field right now either raise or lower the rollers themselves, which moves the centerline of the vessel up or down. It’s possible for the rollers to also be on a slide that moves them left or right, which moves the centerline left or right. Koike’s anti-drift system provides lateral motion and maintains the centerline without moving it at all.

Koike primarily designed the anti-drift system to improve the process of welding heavy-walled vessels, especially when the welding is done for several hours or even one or two days continuously. The system can handle vessels from 10 tons up to 1000 tons.

“If you have a vessel that has a very thick wall, and you have a welding nozzle that’s down between the walls, [the nozzle will] crash into [it if the vessel moves at all],” comments Burgart. “Our anti-drift system can hold a vessel to within a 0.125 in. movement.”

The second new system that Koike has developed is its low-cost programmable positioner controller. This controller, when integrated into the positioner and manipulator of the welding system, can provide up to six axes of control. Positions, speeds and angles can be programmed into the controller and stored in its memory. This can be accomplished either through direct input via the controller’s touchscreen or through a teach mode.

“This is a low-cost system, but it can automate a lot of positions, and it can be added to existing equipment,” comments Burgart. “It’s a lower-cost system than what’s out there.”

Koike’s third new system is its lightweight girth welder. This system is designed for automatic welding on smaller diameter, thinner-walled storage tanks, such as those used for oil, gas or chemicals at refineries.

Tank welding was geared more towards heavy-walled tanks, but Koike saw that there was an increasing demand for equipment to weld thinner-walled tanks. Heavy-walled tanks are 0.5 in. or thicker with 20- to 30-ft. or larger diameters, while smaller-walled tanks are 0.1875 in. to 0.375 in. with diameters as small as 12 ft.

“It’s about 40 percent lighter than our standard machine, but it still has all the benefits [of the standard machine] for doing the girth-seam welding [on smaller tanks],” says Burgart.

Lincoln Electric

For Lincoln Electric, making its welding systems modular essentially means designing them to accommodate customers who might want to reuse them for a different purpose.

“With our system, customers can easily retransfer these cells into a different configuration, as the part runs are sometimes pretty small,” explains Geoff Lipnevicius, Lincoln Electric’s engineering manager.

Beyond these reusable modular cells, Lincoln Electric also produces custom consumables designed specifically for different industry sectors. Since sectors such as automotive, mining and energy all have unique requirements for materials used in their respective material handling, Lincoln Electric will produce customized consumables that match the mechanical properties of the materials.

“Then we build systems around the sizes of the parts that are specific to these segments,” says Lipnevicius. “For instance, earth-moving or mining might be working with heavier and larger parts, and automotive or sheet-metal job shops might be handling lighter-gauge metal.”

Lincoln Electric’s systems also often have positioners to optimize the welding process for faster throughput. In addition, the company looks at anything that will maximize the uptime of its systems – accessories such as bulk wire and reaming stations for example. Welding equipment with a waveform control where the output is customized to specific applications is also offered.

In the area of quality control, Lincoln Electric builds software tools right into its system that function as quality monitors. Lipnevicius mentions that quality monitoring devices historically have cost between $3,000 and $6,000 per unit. However, the quality monitoring that Lincoln Electric provides in its software is included at no extra charge.

The software tools monitor the welding process, and Lipnevicius says, “If something should go outside the set parameter range, the product can be pulled out and sent down an off-feed chute for further analysis or for rework. [The software] then provides statistical data that management and production very much want, so they can tackle and maximize output of the systems.”

Lincoln Electric’s robots are also built with integrated vision, which means that they have some intelligence says Lipnevicius. Using its eyes, the robot will adjust the program based on any part movement.

“The robot can see if there is a pattern match, and if there’s any change to the part,” he explains. “It can then change the program to wherever the part has moved. This is really beneficial for the companies with small part runs and small batches.”

Miller Welding Automation

Three years of market research led Miller Electric to a joint partnership with Panasonic Robotics and the development of the PerformArc system.

“For more than 10 years, PerformArc systems have been setting the standard in the welding industry for quality, reliability and productivity,” says Kevin Summers, Miller Welding automation’s product manager. “These pre-engineered cells were specifically designed for job shops, [and] they are designed with flexibility in mind.

“If you have a high-mix, low-volume product, or if you have multiple high-volume components, we offer a number of different PerformArc products that are really suited for your needs.”

Summers elaborates further, making it clear that it’s really the variety of different PerformArc systems that makes it possible to handle all the different kinds of welding needs that job shops might have.

“We have everything from our PerformArc 250M, which is a very low-end kind of introductory system that might be used for very small dedicated batches, [to other machines like our] H-frame design, which offers plenty of flexibility,” he points out.

The H-frame design features exchangeable head and tail stocks with tooling beds that can accommodate three or four parts. The parts can be either individual or nested, and tooling beds can also be rotated over to fit additional parts or to weld on the underside of the existing part.

The tooling plates and tooling beds can then be removed to allow a new tooling bed to be dropped in that can accommodate a different part type.

As these systems interchange between two sides, the operator is able to load and unload on one side, while the robot works on the other.

“This setup gives [job shops] flexibility, whether it’s welding a large part or smaller volumes of smaller individual parts,” says Summers. “It allows end users to mount or nest individual fixtures on a tooling bed or to change out multiple tooling beds.

The PerformArc Series also helps to make welding automation easy in that parts can be programmed offline with 3-D CAD modeling and then exported to the robotic welding cell. Once the programming software is uploaded to the robot, the robot can start welding, and from there the process can easily be repeated with another robot, too.

Even though the PerformArc Series has been on the market for ten years, constant new innovations keep it up-to-date and fresh. For example, many machines have a light barrier around them for safety, but with the PerformArc Series, the safety distance in which the barrier is activated is shorter, due to the fact that, because the servo indexers are able to respond so quickly to the input command, the turntable can be stopped faster. Summers comments that safety features such as these are constantly being upgraded.

The PerformArc Series can be powered by either the TAWERS System from Panasonic or the Miller Auto Axcess Power Supply. It also features off-line programming software, which simplifies the welding process for job shops, no matter what type of material they’re working with from day to day.

Another strength of the system that Summers mentions is its friendliness toward first-time robot buyers. The PerformArc Series uses Panasonic robots with Windows CE-based pendants and features pull-down menus and file folders, as well as friendly, modern controls.

Miller Welding Automation’s goal in providing all of the aforementioned features on its PerformArc Series is to help job shops boost productivity in welding and simplify the process overall.

“Ultimately, at the end of the day, the importance is to have more good parts in the bucket,” says Summers.

Koike Aronson Inc.
Lincoln Electric
Miller Welding Automation

 

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