Georgia Machine Shop Triples Deposition Rate with Submerged Arc System and Metal-Cored Wire | MillerWelds

Georgia Machine Shop Triples Deposition Rate with Submerged Arc System and Metal-Cored Wire

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Seeking greater productivity and efficiency, especially on larger weld build-up jobs that could take days or even weeks to complete, Capital City Machine Shop knew it needed a new submerged arc welding (SAW) solution. Capital City’s investment in two SubArc AC/DC 1000 Digital welding power sources, coupled with a switch to Hobart® metal-cored wire, resulted in productivity increases of 240 percent on some jobs and deposition rates triple what they experienced with their previous system from another manufacturer.
The shop uses Submerged Arc welding to get the penetration and deposition rate needed with larger jobs and thicker materials, such as build-up welding on a 7-foot-diameter rock crusher bowl.
With a switch to Miller Subarc machines and Hobart metal-cored wire, Capital City can now complete a build-up welding job in 24 hours that previously took 100 hours.
The Capital City Machine Shop
The Capital City Machine Shop specializes in welding and re-machining large industrial machinery and equipment

The Capital City Machine Shop in Doraville, Georgia, specializes in welding and re-machining large industrial machinery and equipment, with customers in industries such as rock quarries, aggregate, construction, recycling and power.  

Launched in 1919, Capital City over the years has added equipment and diversified its work into other types of welding beyond repair to meet changing customer needs. Now with nearly 30 employees and 59,000 square feet, the shop builds business on its reputation for integrity and quality work.

“Over these 95 years, we’ve always been known to do what we say we’re doing to do,” says Charlotte Brown, owner and president of the company since 1986. “We’re committed to the customers, and we have a very good record with our quality.”

Capital City does welding repair in the field and also repair, fabrication and build-up welding in its shop. With about 120 jobs per month on average, the shop offers MIG, TIG, Stick and Submerged Arc (SAW) welding on materials that include mild steel, high carbon, stainless and aluminum — anywhere from 1/2-inch thick plate to material several feet thick. Subarc welding helps them get the penetration and deposition rate needed with larger jobs and thicker materials.   

While Capital City was already using Subarc welding, they wanted a SAW solution that offered greater productivity and efficiency, especially on larger weld build-up jobs that could take days or even weeks to complete.

Capital City’s investment in two Miller® SubArc AC/DC 1000 Digital welding power sources, coupled with a switch to Hobart metal-cored wire, has resulted in major productivity and efficiency gains for the business — productivity increases of 240 percent on some jobs and deposition rates triple what they experienced with their previous system from another manufacturer.

“We’re impressed with the productivity that we’re getting,” says General Manager Mike McClure. “It saves us a tremendous amount of time, compared to what we were doing.”

A more efficient Subarc solution  

Subarc welding jobs were taking the shop anywhere from two or three hours to two to three weeks. A typical SAW job in the shop may involve building up 2 inches of weld on a 7-foot-diameter steel bowl from a rock crusher, so that threads can be re-machined back to specifications on that part. Rework and downtime on these types of large jobs are productivity killers that impact the bottom line.

“It needs to be done correctly the first time, and efficiently,” Brown says. “Because the customers are very large, and they are production companies; they are just losing thousands of dollars an hour when their machine is down. So we are under the gun.”

Capital City wanted to increase arc-on time and productivity, without sacrificing quality. The shop also was experiencing a lot of downtime for service with their previous equipment, and they decided an upgrade was necessary. The shop began exploring solutions to help them remain competitive while maintaining quality and control. They turned to Alfred McClure, with Sidney Lee Welding Supply in the Atlanta area.

Capital City wanted a solution that provided a dual head option, to make more efficient use of arc-on welding time on large jobs. They converted from their previous SAW machine from a different manufacturer to two Miller SubArc AC/DC 1000 Digital welding power sources, offering 1,000 amps each. This provides the capability for the shop to have two welding torches; for smaller Subarc jobs they can use a single torch, and for larger jobs they can use both arcs to increase productivity. With two power sources, Capital City also has the flexibility to run tandem or multi-torch configurations in the future as their jobs evolve.

The easy-to-use interface of the new system helps save operator time in setup. And 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 allows the shop to position the part being welded at different angles. The two new Subarc machines were easily integrated into the shop’s existing positioner setup.

Metal-cored wire triples 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, so 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 like 15 to 18 pounds per hour, and now we’re running at 60 pounds per hour,” says Tim Pieniaszek, welding foreman. “We get our jobs out the door faster.”

And 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, and there is reduced potential for porosity and part rework.

“Switching over to Hobart metal-cored wire has been a great advantage,” says welding operator Rob Stern. “Our deposition rates have just skyrocketed, and it increases productivity.”

Productivity increases up to 240 percent

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 build-up welding jobs, helping the business keep overtime to a minimum compared to their old system.

A typical build-up 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, so the ability to put down more filler metal in a shorter amount of time is important for productivity. It helps the shop move that part to the machining stage faster, improving productivity for the overall process, not just the welding portion.

“On some of these crusher parts, our productivity has picked up 240 percent. We take a job that was taking 100 hours, and we have cut it down to 24 hours,” McClure says. “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 depending on customer needs and deadlines. So the ability to do jobs in less time and have additional flexibility in operator hours is important.

“It’s greatly improved the productivity of our Subarc compartment flow. The customers are happy because they’re getting it back quicker, which in turn brings us more business,” Stern says. “It gives us a better edge on the competition.”

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. That saves operator time in changing out the spools, and results in a safer process since the operators are no longer climbing on top of the machine to frequently change the spools.

“With the 60-pound spools, we were changing one every three hours. Now, we can go 24 hours before we ever change our drum,” Pieniaszek says. “It’s very efficient and easier on our workers.”

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.

All of those time-saving factors have added up for the shop. 

“The machines are actually paying for themselves quicker than what we anticipated,” McClure says. “The return on investment has been excellent.”

A consistent quality weld

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.

The shop counts on the reliability of the new system to help save time and money, since the job can be done right the first time, and the system performs consistently.

“We don’t have the rework we used to have,” Stern says. “Because if you have any porosity in that weld when they start to machine that thing, you’ve lost days and days of productivity. It’s been a great improvement in weld quality.”

Easy setup with digital controls

The new machines are also easy to set up and understand. The interface controls recognize the power source and wire drive connected and automatically configure the system for proper operation. The interface also provides welding operators with the necessary controls to set process parameters and control output.

“This system is much easier to operate,” Stern says. “The old system, we had to constantly adjust temperature. We weren’t getting consistent penetration. Now, we know exactly what we’re getting.”  

The SubArc Digital Series Interface controls are intuitive, which saves time in setup and helps prevent stops and starts to adapt settings during welding, as they had to do with their previous system. The machines also can be programmed for up to 15 different jobs, so switching between jobs with varying parameters is easy and doesn’t require recalculation.

“It will remember it for next time,” says Ronnie Blocker, a welding operator. “When this is set, you don’t have to do anything. Then for the next job, you don’t have to do anything — it’s already programmed.”

A tremendous addition

The Miller Subarc machines and Hobart metal-cored wire have greatly improved productivity and efficiency for Capital City, saving hundreds of operator hours and allowing the shop to take on more jobs and customers.

“It has been a tremendous help. From a customer service standpoint and from a productivity standpoint, it’s just been excellent for us and for our customers,” McClure says. “Our customers, they understand how efficient the system is and the quality of work that we’re putting out. It’s all about keeping the customer happy.”

For a small company like Capital City, reputation is critical to keeping and growing the customer base. It’s the formula that has kept the family-owned business successful and thriving for decades.

“For a really good company, you’ve got to have really good employees and then you’ve got to have the equipment to do it with,” Brown says.