Multiblanking line improves output, creates new opportunities
June 12, 2007
Arme S.A., a Colombian service center, was producing cut blanks for several local, small customers using a 48-year-old Stamco cut-to-length line purchased more than 20 years ago. It served them well over the years, but the company realized it needed to upgrade its technology to take advantage of the market opportunities it saw growing around them.
To generate consistent lengths and maintain flatness, Arme purchased a 60-in.-wide multiblanking line with a turnstile, coil car, payoff reel, precision leveler, crop shear, interchangeable slitter head for side trimming and multiblanking, looping pit equipment, electronic roll feed, high-speed shear, reject/inspection conveyor belt, and a stacking system.
Founded as a small steel processor in the heart of Colombia's coffee-growing region, Arme S.A., Chinchiná has been producing cut blanks for several local, small customers using a 48-year-old Stamco cut-to-length line purchased more than 20 years ago.
The line served the company well over the years, but as Arme moved through the 1990s, management realized they needed to upgrade their technology to take advantage of the market opportunities they saw growing around them.
By the mid-1990s a new management team was in place and was serious about building the company. Led by Jorge Ivan Mejia, general manager and co-owner, Arme began searching for a supplier to help it break into new markets.
"We knew our growth was dependent upon new technology," said Mejia, "and given what we were working with, it would be a quantum leap."
The company's old 48-inch-wide cut-to-length line comprised a payoff reel, flattener, hump table, shear, measuring system with a triggering microswitch for the shear, a conveyor belt, and a stand-alone four-high leveler.
Arme had two major problems with its line. Generating consistent lengths using the hump table and measuring system was a challenge. With length variations as much as 0.157 in., workers often had to rework blanks on a mechanical shear. These secondary finishing operations were time-consuming and costly.
The second problem was achieving flatness. The line's old flattener had very little control. Shape quality problems often precluded the service center from pursuing new business.
The service center's management team presented their problems to Herr-Voss Stamco®. When finished with their assessment, the supplier helped solve Arme's two primary problems, helping to create new opportunities.
Arme purchased a 60-in.-wide multiblanking line with a turnstile, coil car, payoff reel, precision leveler®, crop shear, interchangeable slitter head for side trimming and multiblanking, looping pit equipment, electronic roll feed, high-speed shear, reject/inspection conveyor belt, and a stacking system (see Figure 1).
To correct inconsistent-length problems, the service center invested in an electronic roll feed with accuracies within 0.005 in.
The inconsistent-length problem was solved by adding an electronic roll feed with accuracies within 0.005 in. (see Figure 2).The roll feed is designed with electronic and mechanical features for precise measurements. A gearbox ratio of 4-to-1 and a resolution in the motor's 4x encoder of more than 5,000 pulses per revolution help maintain tight tolerances. This means that for every revolution in the roll feed, the encoder generates 20,000 pulses. Accordingly, with every pulse generated, the roll feed moves 0.00078 in.
The mechanics of the feeder, high-precision bearings, double backup supports to the feed roll, zero-backlash gearboxes, and a precision-machined base all combine to ensure that the precision inherent in the electronics can be transferred to the mechanical movements of the roll feed and ultimately the strip.
Maintaining flatness was achieved by adding a leveler with 19 working rolls and seven flights of lower and upper backups. According to the company, this leveler can produce dead-flat material even on commercial-grade steel. Ultraheavy, welded, stress-relieved top and bottom frames provide rigid platforms for near-zero deflection.
Each of the five adjustable backups is supplied with motorized jack actuators that control the positioning of the rolls with a linear transducer. At the exit of the leveler, an inspection table allows the operator to inspect the material visually as it leaves the leveler.
This line also can be accessed via the Internet.
"Because of the Internet interface we can now troubleshoot any equipment problems without needing a service technician to fly from the U.S. to Colombia," said Mejia. "Now a service call is a matter of minutes, not days."
Once its two major technological problems were resolved, Arme began to concentrate on expanding production capabilities. With the new width capability, the service center can process wider coils, which cost less in international markets. The savings, combined with the company's new multiblanking capabilities, made it possible for Arme to tap into market segments previously out of reach.
As a result, Arme now is a metal supplier to appliance parts manufacturers. The service center says it now has become the new quality standard, raising the bar for any company that wants to get into that market segment.
One of Arme's main purposes for acquiring a multiblanking line was to make a fresh start. With that in mind, managers started interviewing engineers for key positions.
"We didn't want to carry over old vices to our new operation," said Mejia. "Our new staff will know the machine inside out, and they will be in charge of training the operators and maintenance crews."