At Steel of West Virginia, a compact 340,000 tons-per-year mini-mill in Huntington, West Virginia, robots are becoming an increasingly important part of production. They are a sophisticated and integral part of the workings of this 49-acre steelworks, which is a subsidiary of 7,635-employee-strong Steel Dynamics Inc (SDI).
Twenty-six robots, mostly acting as welders or material handlers are scattered throughout the 770,000 square foot campus, in downtown Huntington just metres away from Marshall Universitys engineering complex. Robots inject oxygen through lances, weld pieces of steel, and stack countless piles of beams per year. The oldest robots on site were installed in 1994.
Even these relatively old robots, installed when Industry 4.0 had yet to be coined as a term, can weld about 1.2 million beams per year, Steel of West Virginias operational and commercial executives told Metal Market Magazine during an April 27 mill tour.
Each beam weighs as little as 30 lbs and is commonly used in industrial and automotive applications. Many typically form a cross-member section for industrial trucks and trailers, sold nationwide from Steel of West Virginia. Sheer productivity and consistency are two key drivers of the robots deployed. On our weld lines, were welding a beam approximately every ten seconds, said Scott Boggs, the mills fabrication superintendent. Those robots are doing the same weld patterns every ten seconds, he stressed.
The repeatability on a robot welder is obviously a lot better than any human could do, added Boggs, who oversees the facilitys robotics. Robots, of course, do not suffer from human fatigue or illness. But extensive automation here does not mean that the mill is a ghost town run entirely by machines. Human welders have been retrained to learn how to operate and supervise these expensive robots, which can cost tens or hundreds of thousands of dollars per unit. For example, the works latest tranche of 10 robots, for material handling, was installed at a collective cost of $3.75 million, with Traverse City, Michigan-based TranTek Automation Corp credited for the technology and equipment.
Displaced workers tend to get re-absorbed into the plant workforce, in other areas of the steelworks, said the mills vice-president and general manager Mark Gilliam. In fact the mill is hiring now because the market for its value-added steel products is so good in an end-market that is enabled in part by these robots.
The variety and volume of truck-trailer cross-member beams that Steel of West Virginia welds or coats, assembles and ships is large. Gilliam said the sheer volume and depth of service for its customers is physically impossible without these robots.
The 285,397 tons that the mill produced in 2017, and the profits achieved from those tons, were enhanced by these nifty robots. Besides making things better for profit and loss, its better for employees as its safer, since employees are not now doing so many repetitive tasks, added the companys vice-president of administration and financial controller, John OConnor.
Welding, then waxing
Welding is not the only application for robots at Steel of West Virginia. The newest line of robots, housed in their own separate building, are material handlers. They shepherd yet more steel cross-members, as these run through a mass wax-coating process. These robots in the form of whirring, colorful arms grab the short cross-members from a hanger, flip and return the steel, as appropriate, and finally stack them, after the wax is applied.
Although the ten material-handling robots are outnumbered by their welding associates 16 in total this wax coating process represents a significant slice of the 26% of floor space that the Huntington mill devotes to finishing and value-added services. The mills ability to process, fabricate, and otherwise finish raw steel long products thanks in no small part to its use of robotics contributes value directly to the mills traditional customers, who are often technically demanding original equipment manufacturers (OEMs).
In this case, a wax coating was preferred over traditional steel coats like zinc because wax protects these automotive parts from chipping and all the debris that roads throw up. These wax-coated beams, destined for truck and trailer applications, are produced en masse by Steel of West Virginia, a top US supplier of such cross-members for van trailer and truck bodies.
To see these modern machines at work is a marvel. Even from behind a welding screen, or housed in a wide cage, their precision and efficiency is striking. On the waxing side, where several robots work in the style of an assembly line, robots later in the line can sense what earlier robots earlier have done and can note imprecision or make corrections. In other words, these machines digitally communicate with one another.
Some of our core OEM customers have interest in us doing more value-added fabrications that could also be galvanized, Gilliam later added, noting the potential for further robotics at the company. Where there is enough volume to justify the investment, we would capitalize on our experience with robotics and automate these welding and fabrication processes... Plans are in place to add more robotic fabrication cells.
Robots in construction
Beyond the Steel of West Virginia mill self-described as artisans of steel on their parent companys website robots are hard at work in other areas of the US steel industry too.
For example, on trade floor shows like the one at the American Institute of Steel Constructions major annual conference, held in Baltimore in April 2018, big robots could be seen at work on large structural sections. Robots were a theme at the AISC show, with an exhibition floor that included Lincoln Electrics PythonX robotic fabricator and a giant Peddinghaus Corp PeddiBot installation.
One seminar at the show, aimed at structural fabricators who cut, bend and process steel for construction projects was even entitled: Robotic Welding for Unique Parts, or: How you can weld structural steel beams with a donut and a coffee. AGT Robotics general manager Louis Dicaire explained there how robots could, with sufficient software and sophistication, weld unique parts a challenge in steel construction, where special customized shapes are required that are unique to the building and the steels role in the building.
Dicaire also discussed the wider use of robotics within steel and within industrial manufacturing. Some 150,000 robots now actively work in heavy industry globally, but most work on high-volume production of parts, where many identical components are produced, he told a diverse audience of structural engineers, architects and steel fabricators.
Robotic welding is quite new in structural steel as it is a relatively low-volume business with a highly specialized mix of products, he said. Fitting and welding can represent 50% of a steel fabrication shops operations, with the latter alone taking up 25% of a shops operational time, estimated Dicaire.
Done manually, a human welder usually welds between 10 and 20% of their shift, in on-arc time. The rest of a shift is often spent examining welds, repositioning steel, and so on. With a robot, the rate achievable is 50-65% of arc-on time. In other words, robots will weld more often though not necessarily faster than human welders, Dicaire explained.
AGT Robotics has deployed hundreds of robotic welding systems in North America, often dealing with pallet rack beams and upright frames, while its BeamMaster Weld has four deployments in Canada, the companys marketing director Denis Dumas told Metal Market Magazine.
Robotic welders are starting to be adopted by structural steel fabricators, and the market could move in coming months and years, said Dumas. A lot more fabricators are really thinking about robotics right now, he reported. A couple of years ago, few were the ones ready to make an immediate move. Now we feel that the market is ready, he concluded.
Wielding a plasma torch
At the Peddinghaus stand on the Baltimore Convention Centers show floor, structural fabricators and steel engineers flocked to watch a PeddiBot in action.
An imposing module, the raised PeddiBot-1200 a robotic thermal processor anchored a corner of Bradley, Illinois-based Peddinghaus space. In a demonstration of the equipment, a robotic arm wields a plasma torch behind a screen to cut beams, tube, channels, and angles, fitting them out to specification, sparks flying.
Peddinghaus states that one PeddiBot might easily save a company $250,000 per year, and can do the work of five workers. A six-axis robotic arm allows for dexterous handling, while the robot itself can deal with steel profiles of up to 12 tons in weight. Released last year, the machine is now gaining in popularity, with a number of US deployments to date.
While all the robots described amply demonstrated their value, there are still situations in which only human welders can do the job. For example, robotic welders sometimes cannot access the steel to be welded at the right angles to do the work. In other words, in confined or awkward spaces inaccessible by robot only human welders can do the job.
Written By Nat Rudarakanchana