Coil Processing
Wednesday | 08 January, 2014 | 11:37 am

High-speed slitting

By Tom Klemens

Coil processing line handles range of materials including advanced high-strength steel

December 2013 - With every opportunity comes a challenge. When Roswell, Ga.-based Kloeckner Metals Corp. decided in 2011 to build a new coil processing facility in Calvert, Ala., one of the challenges it faced was finding an equipment line that would handle a variety of product including advanced high-strength steel.

“We looked at a number of different sources for the slitter for Calvert,” says Russ Delaney, president of Kloeckner Metals’ Flat Rolled Group. “After looking at several options, both domestically and off shore, we decided that Braner offered us the best fit and value based on what we were looking to do and for the advanced high-strength steel applications we were particularly designing this slitter to handle.”

The company built its 100,000-square foot-facility beginning in mid-2012 on-site with a new ThyssenKrupp mill, which produces carbon steel, and an Outokumpu mill producing stainless steel. Kloeckner Metals installed and commissioned its new slitter in July and August and the facility was fully operational by the official opening on Sept. 1.


Regional service

The company now has 18 flat roll processing plants in key markets, including a facility in Monterrey, Mexico. “Freight is a large portion of costs, both inbound and outbound,” Delaney says. “And service levels required  by our customers require us to be within a few hundred miles of them.”

Being right on-site in Calvert means inbound logistics expenses are about as low as they can be. “And we feel the Calvert location, just 30 miles north of Mobile, Ala., is well-positioned to cover the southern section of the U.S., where a lot of the growth is going on now and forecast to be in the future,” Delaney says.

The Calvert plant processes a variety of coils such as cold rolled and hot rolled pickled and oiled steel; coated products, which include galvanized, galvanneal, aluminized and prepainted materials; and stainless steel. “We buy coils from the mill, as we do at all our other locations,” Delaney says. “We process them either into slit coils or into cut-to-length sheets or blanks, and in some cases we provide first- and second-stage fabrication to those products to provide our customers with just-in-time delivery in the most efficient form possible.”

The slitting line can run material from 0.010 inches to 0.250 inches thick and up to 74 inches wide. “We can handle 40-ton incoming coils, which matches the mill’s capability as far as coil sizes go,” Delaney says. “And we can produce 84-inch OD slit coil, which is larger than most slitters that are currently installed can provide.” Customers appreciate the larger coils because they reduce the scrap generated by each start and stop.


Heavy duty equipment

In addition to its large capacity, the slitter is designed to run advanced high-strength steels up to 260 ksi tensile strength. Predominantly used in the automotive industry at this time, these materials are becoming more popular in other industries trying to achieve more strength with less weight.

“It’s really a high-strength line,” says Chuck Damore, president of Braner USA, Schiller Park, Ill. “We see trends in the industry going that way. Many of the newer slitters we’re producing today can run this ultra high-strength material.” To be able to do that, he says, means building big machines with big arbors, lots of rigidity and plenty of horsepower.

But because the Braner slitting line is presently Kloeckner Metals’ only equipment at the Calvert facility, it’s also important for the line to be able to handle a wide range of products for various applications. For example, Damore says, this line has the ability to run thin gauge material into a pre-slit loop with a combination drag generator/uncoiler loop drive. “The advantage of that is it provides much better tension control than a traditional pneumatic brake-type uncoiler,” he says. “That means they’re slitting the material tension-free, and that provides improved width tolerances and strip edge quality.”

The slitter itself also is much bigger than on a traditional line. Additionally it has a hydraulic tool lockup feature to provide clamping consistency from operator to operator and from one job to another.

“We’ve also developed an Andiamo threading system that allows you to run a short tab into the slitter, then start the slitting process maybe 6 inches back,” Damore says. “Then you’re threading a single piece of material across the line, rather than 15 cuts, for example. You thread that single piece up to the exit end of the line, then cut it off.” It’s not hard to imagine how simplifying the threading process improves machine productivity, which was one of Kloeckner’s key criteria.

Equipping the line with a two-position turret recoiler was a further boost to productivity. “With that, you can do all of your banding and coil preparation offline while you’re winding a master coil in the line,” Damore says. “So the line is never down to put outside diameter bands around the finished coils. Having a turret recoiler will improve slitter uptime by as  much as 50 percent.” 


Full speed ahead

With such productivity-enhancing features at the beginning and end of the line, slitter throughput capacity becomes a critical consideration. This particular installation can run at 1,000 feet per minute, but because appearance is an important factor on much of the material being processed, Kloeckner Metals installed a Cognex surface inspection system on the line. “It is basically a photographic system that can see defects down to 1⁄10,000 of an inch on both the top and bottom surface,” Delaney says. Although Cognex has installed this type of equipment in numerous mills, this is the first such installation in the service center industry. “It will really allow us to be able to run this equipment at high speed and still be able to detect defects that are actually smaller than what a human eye would see,” he says.

Because the company anticipates running a wide range of products on this line, it has been outfitted with a range of tensioners as well. “Multiple tensioning devices allow them to run both a wide thickness range and a range of products,” Damore says. “There is a tension device for oiled material, critical surface, and a different tension device for dry material, critical surface. Those are roll tensioning devices. And there’s a pad tensioner for non-critical surface material.”

“We also have the capability to re-oil coils on this slitter,” Delaney says. “Some end users require special oils on their material, so that’s another advantage of this line that you don’t often find on slitters.”

As if that weren’t enough, the line includes Braner’s patented inline cluster leveler that corrects problems in the incoming coil. “If the material has a wavy edge or center buckle, the inline leveling capabilities on this line can shape correct it while they’re running at speeds up to 1,000 feet a minute,” Damore says. “It’s a huge advantage because it allows them to enhance the value of the strip.”

With all the features on the slitting line designed to optimize throughput, it becomes important to process the finished product rapidly as well. Braner supplied a packaging line designed to keep up with the high production rates. “Once coils come off the slitter, they go onto a turnstile to stage the coils downstream,” Damore says. “Then we have an automated packaging line that takes coils automatically through a traversing downender. As the downender lifts each coil off the turnstile, it rotates the coil 90 degrees and sets it on a conveyor. From there it goes downstream through a strapping station where bands are applied around the coil.” A turret stacker places the banded coils on skids where they are weighed and covered with stretch-wrap for shipping.

Although Kloeckner Metals began with one shift at the Calvert plant, it anticipates growth opportunities down the road. “We’re on property where we can expand up to 400,000 square feet,” says Delaney, “and we do have rail there. So we are intending to grow this business, initially with the Braner slitter that we put in, and then as our customers have other demands for other processes.”

Meanwhile, the operation is off to a good start. “Braner delivered the equipment on time, it was installed on time and was commissioned with minimal startup issues. We are very happy with its performance.” MM

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