The Capital City Machine Shop in Doraville, Georgia, specializes in welding and remachining large industrial machinery and equipment. The company has added equipment and diversified its work beyond repairs. “We’re committed to the customers and we have a very good record with our quality,” says Charlotte Brown, owner and president of the company since 1986.
Capital City does welding repair in the field, and repair, fabrication, and buildup welding in its shop. With about 120 jobs per month on average, the shop offers MIG, TIG, Stick, and Submerged Arc welding (SAW) on such materials as mild steel, high carbon, stainless, and aluminum. While Capital City was already using SubArc welding, it wanted a SAW solution that offered greater productivity and efficiency.
EFFICIENCY SOLUTION
SubArc welding jobs were taking the shop anywhere from 2-3 hours to 2-3 weeks. Rework and downtime on large jobs are productivity killers. “It needs to be done correctly and efficiently the first time, because the customers are large; they are production companies; they lose thousands of dollars an hour when their machine is down.”
Capital City wanted to increase arc-on time and productivity without sacrificing quality.
Deciding an upgrade was necessary, the shop explored solutions to help remain competitive while maintaining quality and control. Capital City turned to Alfred McClure with Sidney Lee Welding Supply in the Atlanta area.
As a solution to make more efficient use of arc-on welding time on large jobs, Capital City acquired two Miller SubArc AC/DC 1000 Digital welding power sources, offering 1,000 amps each. The easy-to-use interface of the new system helps save operator setup time.
Because the interface controls can automatically configure the system for proper operation, it results in consistent, high-quality welds and reliability for the shop. An existing column and boom positioner system, in which the new SubArc machines were easily integrated, allows the shop to position the part being welded at different angles.
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Feature Image: Capital City’s general manager says its productivity has picked up 240 percent, allowing the company to be more efficient and handle more jobs.
Above: As a solution to make more efficient use of arc-on welding time on large jobs, Capital City acquired two Miller SubArc AC/DC 1000 Digital welding power sources, offering 1,000 amps each.
TRIPLE DEPOSITION RATE
In converting to the new SubArc machines, Capital City also switched from solid wire to metal-cored wire. The SubCOR™ EM13K-S MOD metal-cored wire from Hobart allows the shop to get a much higher deposition rate. Welders can put down more metal in less time to complete jobs faster, without sacrificing weld strength or toughness.
“On our old system, we were running 15-18 pounds per hour. Now we’re running at 60 pounds per hour,” says Tim Pieniaszek, welding foreman. Because the wire offers improved tolerance to rust and mill-scale compared to solid wire, the shop saves time in cleaning and preparing the material before welding. “Switching over to Hobart metal-cored wire has been a great advantage,” says welding operator Rob Stern. “Our deposition rates have just skyrocketed.”
PRODUCTIVITY INCREASES
With the deposition rate more than tripled, Capital City is able to shave hours—even days—off the time it takes to complete SubArc welding jobs. The difference has been especially noticeable on large buildup welding jobs. A typical buildup job on a rock crusher part can involve putting 2 inches or more of weld metal around the outside of a crusher bowl as the bowl is slowly rolled on the positioner. The ability to put down more filler metal in a shorter amount of time is important for productivity, helping the shop move that part to the machining stage faster and improving productivity for the overall process.
“On some of these crusher parts, our productivity has picked up 240 percent,” says general manager Mike McClure. “In the time that we save in these jobs, that’s time that the same employees can be working on other jobs.” The shop may have 30 or 40 jobs going at any given time and priorities can change by the day. Beyond the increased deposition rate, there are other factors from the conversion that have contributed to greater productivity for Capital City.
With the switch to metal-cored wire, the shop also went from using 60-pound spools of solid wire to using 600-pound drums of wire, saving operator time in changing out the spools and resulting in a safer process. “With the 60-pound spools, we were changing one every 3 hours. Now, we can go 24 hours before we ever change our drum,” Pieniaszek says.
Capital City also switched to Hobart HN-590 flux in the change to metal-cored wire. The easy-releasing flux designed for SAW applications is another time-saver for the shop, contributing to increased productivity since it reduces the time operators must spend chipping slag from the weld.
END RESULT
Capital City has experienced the great productivity gains with the new Miller SubArc AC/DC 1000 Digital welding power sources and Hobart metal-cored wire and flux without compromising weld quality. The shop sees consistent welds and hasn’t experienced problems with cracking or inclusions. “We don’t have the rework we used to have,” Stern says. “It’s been a great improvement in weld quality.” ■
For More Information: To find out more about Capital City Machine Shop, visit www.capitalcitymachine.com. For more on Miller’s products and services, visit www.millerwelds.com. For more on Hobart’s products and services, visit www.hobartbrothers.com.
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Modern Contractor Solutions, October 2015
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