The cold-formed steel industry's competitive environment is driving todayâ¢s manufacturers to streamline operations and adopt technologies to increase efficiency and add value to end products. California Expanded Metal Products, known as Cemco, took these business practices a step further when it developed an innovative floor joist system called Sure-Span.
The system required new roll-forming, embossing and flaring technologies that could meet evolving consumer demands, strict industry standards and Cemco's criteria for quality and affordability. The company's manufacturing and engineering teams were tasked with finding a press that could anchor the line and fabricate complex parts.
Based in City of Industry, Calif., Cemco has four production plants and is one of the largest manufacturers of steel framing and metal lath systems in the United States.
"In 2001, one of our principal competitors was working on developing a system similar to our concept," says Georgi Hall, director of engineering at Cemco and the inventor of Sure-Span. Aware of the competition, Cemco decided it needed a product that would give it an edge. Hall completed development of the light-gauge steel floor joist system in 2002.
Sure-Span's patented system can support both commercial and residential construction projects. Unlike conventional floor joists, Sure-Span features large trapezoidal-shaped punch-outs that give plumbing, HVAC and electrical contractors built-in access for a variety of services without sacrificing the structural integrity and sturdiness of long floor spans.
"Traditional over-sized or atypically large punch-outs compromise the floor joist's overall capacity and structural integrity," Hall says. "Our system eliminates this problem with specially designed flares and embossment. These features counter reduction of sectional strength due to holes. As a result, Sure-Span exhibits equal or greater strength capacity when compared to floor joists with no punch-outs." Prototype testing verified Hall's findings.
To produce the floor joists commercially, Cemco needed the right press. The manufacturer submitted drawings to several press manufacturers but found the recommended machines complicated and too expensive.
THE RIGHT PRESS COMPANY WAS SUTHERLAND, (Testimonial)
"Though an experienced roll-forming company, this type of flaring and embossing was new to us," says Hall. "We needed press technology that we could understand and easily train our personnel on. We didn't need machines with a lot of bells and whistles. We wanted something simple to maintain that could accommodate our die designs and our budget."
Sutherland Presses, Malibu, Calif., offered a practical solution. "They evaluated our requirements and provided us with an affordable turnkey manufacturing line," says Hall. "The floor joist system represented a carefully developed and tested new concept. Sutherland gave us a simple solution capable of performing a complex job." A global press supplier, Sutherland provides built-to-order mechanical, hydraulic and forging presses as well as feeders and automation options.
In addition to punching, embossing and flaring, Cemco operators needed to cut joists to custom lengths within strict tolerances all on the same manufacturing line.
"We came up with the idea of bolting an air-over-hydraulic shear onto the second press," says Hall. "Sutherland helped us integrate the shear into the system. Without their help, we would have been required to purchase an additional 100-ton press, preventing us from achieving the small footprint we needed for the line's placement. Sutherland's engineers took the equipment we made and incorporated it into a system of servo controls, which allowed our operators to run the entire line automatically."
Hall also worked with Sutherland to design the press windows to ensure they were large enough to accommodate a 24-in.- wide piece of flat stock.
With more than 65 years of experience, Sutherland knows its machines and the unique requirements of North American customers like Cemco. "We specify each component that goes into a press," says Mark Sutherland, president of Sutherland Presses. "The ability to quickly supply off the shelf components is a key part of our service support."
For Sutherland, however, it's the press builder's philosophy about the vender/customer relationship that sets the manufacturer apart.
"It's a joint effort - a partnership," he says. "Cemco was clear about their challenges and goals. By taking the time to listen and understand their process, our team was able to both optimize and simplify the line to meet their needs. We've seen all types of materials - sheet, coil and plate steel - being produced in some form. That gives us a data pool we also can draw from to help customers with unique requirements."
In 2002, Sutherland installed two sets 176 ton mechanical straight side presses with compact servo feeds (24â¢ x 10,000 lb Coil Reel and Coil Car). The floor joists are produced from hot-dipped galvanized, mill certified prime steel 18 gauge to 12 gauge in Widths of 71.4" to 14". Coating thicknesses can be G-60 or G-90. Part lengths range from 8 ft. Up to 60 ft.
The Sutherland coil line, two presses and shear are operates with a single control system. Strip coils are fed to the first press, which performs punch-outs every 4 ft. The second press initiates flaring and embossing. The line can produce punch-outs for things like water lines, copper piping and air conditioning. Openings also can be punched in various patterns.
Sutherland basically broke our process down into seven commands for the servo feed, says Hall. Our operator plugs in parameters like part length, feet per minute and how many joists the part run requires. The feeder recognizes the reference points for the punch outs and will run automatically. Called gag feeding, the servo can be programmed to accommodate irregular or varied feed lengths within a part run.
In addition to floor joists with large, flared punch-outs, Hall developed a pre-indexed, pre-spaced Sure-Span rim track that provides easy installation while meeting joist spacing, engineering and building-code requirements. During the first two years of production for these framing components, Hall noticed a lot of scrap generated from the trapezoidal punch-outs. Hall got the idea to take the scrap and turn it into a clip that fastens to the rim track with screws. The floor joist attaches to the pre-installed clip.
The clip was a part we originally outsourced, he says. Since we use a modular die system and the press bed size was large enough, we were able to accommodate a new die to form the clips. Trapezoidal coupons are manually fed into the press and cropped into rectangular pieces before being punched with specified features and holes. The third die station forms a bend and finishes the part. We are always looking for new ways we can use the presses.
We encourage you to contact TEAM SUTHERLAND when you have a challenge in your pressroom.