Coil Processing
Thursday | 08 September, 2016 | 1:13 pm

Doubling down

By J. Neiland Pennington

Above: The crop shear in Liberty Steel's Butech Bliss multi-blanking line, followed by the slitter. The crop shear is hydraulic; the slitter has an 11-inch-diameter arbor and accepts 18-inch-diameter knives.

A northern Ohio-based coil processor achieved a two-fold increase in output by replacing its multi-blanking line

September 2016 - Liberty Steel Products runs 3,200 tons of sheet per month through its new multi-blanking line but it keeps that pace with one shift, compared to two shifts with its previous line. Commissioned in December 2015, the Butech Bliss-built line effectively doubles the coil processor’s capacity.

Founded in 1965 in a 4,000-square-foot warehouse in North Jackson, Ohio, just west of Youngstown, Liberty Steel has expanded to 300,000 square feet in North Jackson and Hubbard, Ohio, 30 miles away. In addition to the new multi-blanking line, the North Jackson service center features a lighter-gauge blanking line, a cold-rolled cut-to-length line and a 72-inch-wide slitter. The Hubbard plant specializes in slitting and operates three lines.

Liberty supplies slit coils, sheets, blanks and prepainted coils for a variety of applications, including outdoor and office furniture, small-diameter tubing and pressure vessels. About three years ago, Liberty Steel diversified by starting up a building products group, primarily using prepainted coils, says Steve Ranellli, general manager of sales. “We have relationships with processors throughout the eastern part of the country. We send them orders; they paint for us and we ship from their floors.”

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Butech Bliss, Salem, Ohio, engineered and built the latest multi-blanking line which, besides boosting volume, increases Liberty’s gauge capacity.  

Formerly limited to a maximum thickness of 0.25-inch, Liberty Steel now runs 0.375-inch-thick material. At 3⁄8 inch, the maximum yield strength is 60,000 psi; 80,000 psi is the upper limit for 1/4 inch. One of Liberty’s prime markets is pressure-vessel quality (PVQ) steel, and the Butech Bliss line gives the company the capability to process heavy gauge, high-strength coils. All of Liberty’s inventory can be run on the line, but executives estimate 98 percent of the material it processes is cold-rolled steel.

The Butech line accepts a maximum mill coil width of 74 inches at a maximum weight of 50,000 pounds. The uncoiler, coil snubber and peeler feed into the company’s Synergy hydraulic leveler.

The trade name Synergy indicates a leveler with two work-roll clusters nested in one cassette. “It’s like having two roller levelers in one,” explains Lisa Liposchak, manager of marketing and advertising at Butech. “Having both sets of work rolls in one cassette reduces changeover time.” It’s the feature that allows Liberty to process thicknesses from 3⁄8-inch down to 0.07-inch thick with the same leveler. The previous minimum thickness was 0.10-inch.

The Synergy leveler provides superior flatness compared with the previous line across the range of thicknesses, which opens Liberty up to a wider customer base. Leveler settings can be saved from previously run coils and recalled for repeat blanking jobs.

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Continuous scrap removal

Following the leveler is a pinch roll, a hydraulic crop shear with an adjustable knife and a slitter with arbors 74 inches wide by 11 inches in diameter. The shear accepts knives 18 inches in diameter. Following that is an edge trimmer with two continuously operating helical scrap choppers. 

“With the old line, the scrap was handled inside the building with cranes and pallets,” says Liberty Products President Jim Grasso. “We used winders, and had to tie off the bundles of scrap and move them with an overhead crane. We stopped the line to remove the scrap.”

Now, he says, cutoff material is removed with the line in operation. “The scrap goes through a conveyor outside the building to a covered mezzanine.” Hauled away from outside the building, the process is “safer, and the collection people don’t have to enter the building.”MCN button 2015 2

Following the edge trimmer is a looping pit; a fixed, direct-drive hydraulic guillotine shear with quick-change knives and automatic knife gap adjustment; a blank conveyor with a 10-foot-long inspection table; and a multi-drop stacker.

The stacker is 20 feet long with a minimum mult width of 8 inches. Each pallet has a 5-mult capacity, loaded by motor-driven rotary drop arms. Side and end alignment tamping is pneumatic; the only manual operations are banding and unloading.

The Butech line increases Liberty’s length capability. “We can make multiple cuts, five cuts across, from an 8-inch minimum to a maximum of 240 inches,” according to Grasso. “We struggled before with that maximum length.”

Tolerances are dependent on blank length, says Matt Frisby, vice president of operations. But tolerances are now held to at least twice the requirements achieved with the former equipment.

“The line is running within 0.015-inch on length, and is tighter on diagonal measurements. We have the ability to adjust the shear according to the X-Y coordinates and enter them into the control computer,” Frisby says. “It creates the adjustment that changes the position of the shear with servo motors.”

Speeds for the new blanking line range from 125 to 250 feet per minute. “Everything 1⁄4-inch thick and below, we run in loop mode, so that the line operates continuously,” Frisby continues. “From 1⁄4 inch to 3⁄8 inch, we run in tight mode, and the entire line pauses for each cut.”

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Laser-guided strip steering

Three sets of edge guides position the strip through the line. Guides are at the exit of the leveler and the looping pit, and at the entrance to the shear. In addition, a laser-guided tracker on the infeed steers the coil as it unwinds and maintains the center line.

The line upgrade began Labor Day weekend 2015 with the removal of the old equipment; the first tests were run on the new line in November. It was producing commercial products the following month.

 Grasso welcomed that rapid pace. “One of the benefits we had in working with Butech Bliss was its ability to run the line under power at its own facility. A lot of pre-wiring was done, so our installation here was fairly quick. We had foundations ready; the equipment came in, and we pulled a minimum amount of wiring.”

The learning curve for the Butech line was shallower than Liberty expected. Several operators attended leveling theory classes at Butech and worked with the machinery in Butech’s test facility.

Laser alignment contributed to both speed and accuracy of installation (see sidebar, below). “Butech’s laser alignment allowed them to locate key positions, including the lever rolls and the slitting head, more accurately than with a transit,” Grasso adds. “We have had no alignment issues whatsoever.”

Liberty Products managers are bullish about this latest acquisition. This line will operate for many years, they say, and it should be fully amortized in five to seven years. MM    Photos: Lisa Liposchak

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MM 0916 coil image4A Faro Inc.-built Vantage laser tracker now calculates alignment data when Butech installs processing lines, increasing both accuracy and speed. The laser is a non-contact portable coordinate measuring machine that reads reflected beams from a mobile target. Faro rates the laser as accurate to 0.0006 inch with a spherical working volume of 525 feet.

The ratings are under ideal conditions, indicates Darryl Miller, laser tracking technician at Butech. “Those [figures] are environmentally dependent,” he says. “For example, there is the possibility of vibration in the floor. We see [accuracy within] 0.001- to 0.0015-inch in the environments we work in.” 

The Vantage will measure more than one machine from a single location. Mike Hiet, Butech Bliss quality manager, describes the alignment process then and now:

“With a transit, the installers would align each machine separately. With the laser, they can line up multiple components in one setup. Being able to check the position of multiple machines from one location is more accurate than moving the measuring device for each measurement,” Hiet adds.

“We can also take what Faro calls dynamic measurements,” notes Miller. “They can adjust the machine to the correct position in all three directions (X, Y and Z). With a transit you can’t do that because it checks—at most—two directions.”

The limitation of the Vantage is that it operates only in line of sight, according to Miller. Although you cannot make indirect measurements, you don’t have to move the machine if you can see the aiming point.

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