Christopher A. Bailey, general manager Automation Division, The Lincoln Electric Co., Cleveland. Edited by Leslie Gordon, associate editor.
Lincoln's robotic welding systems provide economical automation even for batches of 50 or 100 weldments.
Pre-engineered robotic welding systems from Lincoln Electric automate both short-run and specialized production applications.
Welding equipment and robotics manufacturers are increasingly forming strategic alliances that reduce customer costs.
Think automation is only for the big boys? Think again. Shops of almost any size can incorporate automated-welding systems and improve quality and repeatability, speed production cycles, reduce downtime, and boost profits. Such "mass-appeal" systems feature easy programming, flexible workholding, and cells with close coordination between weld control, robotic motion, and workpiece positioning.
While conventional wisdom says automated robotic welding only makes sense for long runs of repetitive parts, shops running various batches of 50 to 100 weldments reap many of the same benefits as those producing hundreds or thousands of identical assemblies. And large firms benefit too by automating their short-run or specialized production-welding applications using "packaged," preengineered systems easily programmed to accommodate changing needs.
No matter what size the business, today's strategic alliances between welding equipment, robotics manufacturers and positioner builders put even custom cells well within the reach of shops running small-lot applications. Such systems make economic sense because they minimize dedicated fixturing and make switching production from one part to another easy.
Shops looking to automate should consider the 80/20 rule, which states 80% of a company's production typically represents only 20% of its part sizes. With that said, new robotic welding cells not only make it easy to automate simple, often repetitive jobs, they are now more affordable than ever and give a greater ROI for short to medium-run applications than using the larger, customized welding lines.
Besides making economic sense, automating delivers consistent quality. The fewer uncontrolled variables in the process, the higher the weld quality and the more uniform they are. Improved quality and faster turnaround time, in turn, help create greater customer satisfaction.
An other important reason to automate is the shortage of trained welding operators. This situation creates an "automation imperative," where it makes sense to transfer skills to machines and automate as many repetitive tasks as possible. So even when operators are involved, labor content is low. That's because handling and welding occur simultaneously in robotic cells. Operators load and unload in one area, while robots weld in another.
In the loop
Connectivity between system components is what distinguishes today's systems from those of just a few years ago. For example, new industrialcommunication networks create continuous loops for feedback and process control, from office computer to factory floor and back.
Digital communications also make these systems much faster and more flexible than older analog ones. In addition, users easily add parameters without adding more wires.
With combinations of equipment, software, and communications technologies, manufacturers create advanced arc-welding platforms that provide seamless integration and high-speed communication between welding equipment, PLCs, remote I/Os, and networked computers. Continuous feedback to PCs lets process evaluation happen in real time, without separate external monitors.
One such advanced welding system is The Lincoln Electric Co.'s Nextweld, which provides seamless integration of Waveform Technology, digital communication, and weldingconsumable technologies. Because arc waveforms are shaped electronically with software, equipment with waveform control delivers customized results for each application without changing electrical components. Companies can even create customized waveforms and download them from the Web.
Software customizes welding-arc qualities to match tasks at hand, so one machine now adapts quickly and easily to a wide range of applications with varying material specifications, weld positions, and strength/ appearance requirements. Additionally, inverter power sources can run on almost any power supply with a high-efficiency rating to save energy and money.
An open protocol
In 1997, Lincoln introduced ArcLink, its digital-communications protocol for the arc-welding industry. ArcLink is an open protocol, meaning all companies in the welding industry can use it. This in turn lets more system components communicate effectively.
Protocols such as ArcLink govern the exchange of information between devices or modules in arc-welding systems. Typical modules include power sources, control boxes, and wire drives. Peripheral equipment such as fume extractors and gas mixers are also included. In addition, ArcLink's gateway module links with other company networks, including DeviceNet and Ethernet. With a standard protocol, system integrators have greater flexibility in choosing welding equipment and peripherals and far fewer compatibility problems as compared to having numerous protocols.
Tips for selecting automation
When evaluating automated solutions, shops should determine potential suppliers' capabilities. Some weld-equipment manufacturers offer more technical welding expertise, arc management, process refinement, spatter control, and final-weld quality capabilities as compared to others. Shops should compare available offerings with present requirements and ensure that the selected system can also meet future challenges.
Some manufacturers' teams can use shops drawings or CAD files and build detailed computer models of the part to create 3D animations for accurately simulating the proposed automated-production process. This simulation provides benefits such as:
- Discovering and eliminating bottlenecks, inefficiencies, and safety issues
- Analyzing how operator performance could impact production and flow
- Exploring multiple parts scheduling
- Verifying and/or correcting process assumptions and timing issues
- Examining alternate floor layouts to optimize space
- Identifying potential torch/part/ tooling interferences
- Estimating and studying cycle-time options to increase product throughput
Some manufacturers automationdevelopment teams can also repurpose or upgrade a customer's older robots for use in new systems, thus converting less productive machines into profitable assets.
Tandem MIG boosts output
Manual MIG (GMAW) welding of rear bolster assemblies couldn't keep up with the orders at Garden State Chassis, Woodbridge, N.J. So the company, a producer of high-quality chassis for loading and unloading ship cargo, switched to Lincoln's automated Tandem MIG system and increased production by 500%.
Rather than two arcs welding simultaneously on each side of the bolster assemblies at conventional travel speeds, the Tandem MIG system lets two arcs make a single weld at speeds 4 to 5 times faster. In addition to speeds exceeding 40 ipm, the system delivers high weld quality with minimal spatter, a benefit well-suited for the highly visible bolster-assembly welds.
Pat Picazio, director of purchasing, says, "We can't believe the difference Lincoln's welding system has made in our production abilities, especially as the volume of business increases. We were afraid the automated system wouldn't hold up under our shop conditions, but it runs 8 hr/day, 5 days/week, non-stop, without problems."