July 2007 - Independent Metal Sales, a metal service center in Hainesport, N.J., wanted to boost its productivity and improve its competitive position by upgrading and modernizing its two slitting lines, one an 18-inch and the other a 48-inch line. IMS knew this would cost money but the company was determined to get the maximum bang for its buck. That's where K&S Machinery Corp., Linden, N.J., came in. K&S designs and manufactures an array of coil processing and handling equipment, including slitting, coil packaging, embossing, rewind and coil entry lines.
"We decided to go with K&S Machinery for a variety of reasons," says Jim Papania, one of the principals of IMS. "We've worked with them in the past so we know they are good people to do business with--they say what they're going to do and they do what they say. Plus, they are very competitive in terms of price."
The project kicked off in early 2006. By early 2007 the revamped slitter lines were up and running. On the 18-inch line K&S installed a precision slitter stand with slitter head, bridle-type entry table with swing-out bracket, an exit pinch roll assembly and a new 15-horsepower DC drive system. Used on some CNC machining center ball screws, the quadruplex design is new to the coil processing world. It boosts the axial rigidity of the slitter arbors, resulting in superior edge quality and tighter strip width tolerances.
Work on the larger line was more extensive. "We wanted to expand the width and gauge capacity of the 48-inch-wide slitter to 52 inches," says Papania. "Going out an extra few inches would allow us to buy and process larger coils and thus be able to get more cuts in one run."
At the front end of the line K&S refurbished the old uncoiler, removing its existing AC positioning drive and replacing it with an 8-inch bore hydraulic cylinder and adding a valve stack for use with an edge guide control system. A K&S automatic brake control unit was installed to automatically control the brake's air. This control unit boasts an ultrasonic diameter sensor and PLC with an E/P transducer to maintain brake tension proportional to coil diameter. In addition, the feed clutch was replaced, and the existing edge guide unit was refurbished and repositioned.
At the back end of the process, the line's old recoiler was completely overhauled, increasing its capacity from 20,000 pounds up to 30,000 pounds. K&S designed and built a new 20-inch-diameter-by-56-inch-long collapsible drum with full-length material gripper and nitride-hardened outside diameter, new larger diameter arbor and bearings, a new holding brake, and a new counterbalance cylinder and brackets to increase the capacity for larger coils. They also gave the recoiler some much needed muscle.
"They didn't have enough horsepower on the recoiler so their jobs were running sluggish," notes Nick Cereste, co-owner of K&S and a tooling specialist. "The drive was just chugging along; it was tired, so they weren't getting the productivity they needed." This was corrected by a new 50-horsepower DC drive system.
Productivity was also aided by the new recoiler drum because the old one had been in need of frequent maintenance, making it a source of downtime.
K&S built a new 52-inch slitter head, which was mounted on the existing 48-inch slitter stand and powered by a 25-horsepower DC drive. As with the slitter head on the 18-inch line, a quadruplex bearing design was employed. Here, a Messerfabrik Neuenkamp GmbH, Remscheid, Germany, precision shimless tooling system, supplied by K&S's sister company United Tooling Corp., was used. The tooling system employs Windows-based Neuenkamp software to calculate the most suitable and economical slitter head tooling configuration for each job, then illustrates the optimal setup sequence with graphical printouts.
"Since it's all computerized, with no shims involved, setups can now be a matter of minutes in some cases," says Papania. Gene Grebloskie, director of sales at IMS, adds that "without the variability of shims, which can wear out over time, we get improved width tolerances. Also, with shims you always get some sloppiness that will give you a burr on the edge of your steel. With shimless tooling we've pretty much eliminated that burr."
According to Cereste, the new system pretty much eliminates mistakes, as well. "Since the graphical printout tells you what knife goes where, and shows you where each spacer goes, it takes out the guesswork, not only expediting the process but also minimizing the possibility of errors."
Arguably the stars of the new tooling system are Neuenkamp's high precision knives. "They're capable of cutting stainless steel, nickel, high performance alloys, carbon steel, aluminum, red metals--you can cut a multitude of materials with this type of knife," notes Grebloskie. And cut them with extreme precision, achieving cut tolerances of +/-0.00004 inches. "Another benefit is their longevity. That's a big plus since it's very expensive to keep buying knives."
"It's hard to estimate the lifetime of a tooling knife," says Cereste, "but the quality of these knives coupled with the precise setups they now get will mean significantly longer life. With IMS's old 48-inch slitter, the knives were clanking into each other because the shoulders of the slitter were errant. Now, the shoulders are perfect so the knives aren't touching each other. Put these factors together and that should equate to 30 percent to 40 percent more life than what they were getting out of their knives."
Summing up, Papania says, "This tooling package is as advanced as you can get."
More and better cuts
The revamped lines had a dramatic effect on IMS' capabilities. "Our old 48-inch line was capable of cutting material as thin as 0.0065 inches and maxed out at 0.060 inches," says Grebloskie. "Today, on the new line we can go down to 0.0055 and can go up to 0.130. We've essentially doubled the gauge range. And the amount of cuts we could do at one time on the arbor was limited on the old machine, which meant we'd have to do a double pass on a wider coil. Consequently, we would have to handle it twice, whereas on the upgraded machine--because of its power--we can take the same gauge and cut the whole coil at one time, eliminating that extra handling."
Less handling and more cuts per hour spell cost savings, which Papania cites as one of the key benefits of the upgraded equipment. "There were several things that we hoped to achieve, and in fact did achieve, from this process, and I would say that cost savings was No. 1. No. 2 was improvement in quality. By modernizing the slitters, particularly by going to 52 inches wide, as well as the new tooling system, we've improved the quality of the cuts dramatically."
Papania says the width tolerance on the 52-inch line is now 0.002 inches. "Previously the best we could do on the larger line was 0.005 inches," he explains. "Tolerances are even better on the 18-inch line. Before we were at 0.005 inches on that line and now we're down to a width tolerance of 0.001--a tremendous improvement. So, width is critical and we've nailed that, and the burr is critical and we've pretty much eliminated those."
Another key factor is productive capacity. "Our capacity has more than doubled. That's because of the speed of the machines, the number of cuts on the arbor now, the power of the motors and the various other operational benefits that we've gained through this modernization." He stresses that this is simply the result through the first quarter of 2007 and that IMS is still on a learning curve with the new equipment.
"The more familiar our operators get with the equipment and the changes in the tooling, we foresee not only a two- to three-times improvement, but maybe even greater than that."
Cereste stresses the cost of these improvements. "It's important to note that they received these productivity gains at 30 percent to 50 percent of what it would have cost them to put in new slitting lines. The message to other service centers is: Don't think you're out of the race just because you can't afford a new line."
The project has also impacted IMS's business strategy. "We can go after a much broader range of products now," says Papania. "Previously the thickness range that we could process was limited by our equipment; now that the equipment has been updated the range of thicknesses that we can slit is greater. That allows us to go after a certain market segment that we were unable to go after before."
Though the slitting lines have captured most of the attention, the modernization program hasn't stopped there. The processed coil packaging system was upgraded in another project. In addition, remote controls installed on IMS' receiving crane now allow one person to unload incoming coils from trucks where previously two or three people were required to perform the task. Not only has this saved time and money, it has also freed up time to organize the coil storage area in a more space-saving manner, increasing storage capacity and contributing to IMS's ability to handle increased levels of business as it strives to penetrate new markets.
The route to the sky
No survey of IMS's revamped operations would be complete without a mention of the Sky Loop Accumulator. Though it may sound like something from a science fiction novel, the Sky Loop Accumulator fills a very down-to-earth need. "The depth of our looping pit was limited due to our high water table," says Papania. "So I thought, if we can't go down, why not go up?" The Sky Loop Accumulator was developed and patented by IMS and will be available later this year through K&S' marketing arm.
The device enhances a shallow pit, such as the one at the IMS plant, by guiding the coils down into the pit, up into the air above the pit, down into the pit a second time, and then up to the recoiler. For facilities without a pit, the device creates a "looping pit in the air." Either way, it allows plants to run larger and tighter coils.
IMS plans to market the device with help from K&S. "We expect units to be available in the fall," says Cereste, "and we're going to be vigorously promoting this. It's a very economical alternative for people who are limited in terms of a looping pit. If you can't go down, why not take the route to the sky?" MM
By Greg Farnum, from the July 2007 issue of Modern Metals.