March 2007 Edition

LASERS

Laser Unit Cuts Tube and Time

What took four people working 60-hour weeks is now done by one employee in a 40-hour week

Ellcon-National’s been working on the railroad all the live-long day – since 1910 when C.R. Ellicot of the Westinghouse Air Brake Co. and W.L. Conwell of the Safety Car Heating & Lighting Co., together with J.J. Sinclair of the Westinghouse Electric Co., formed Ellcon in New York State to manufacture and supply products to the railroad industry. Ellcon product lines included diaphragms, step boxes, and safety treads for steam engines and stanchions, handrails, and hollow metal doors for passenger and subway cars.

The laser cutter’s improved efficiency permits one employee to do in 40 hours what took four employees 60 hours to accomplish

Thirty years later, Ellcon bought the National Brake Co., Buffalo, NY, that manufactured emergency hand brakes for the railroad industry. The two companies later merged to form Ellcon-National. In 1991, the company moved to its current headquarters and manufacturing facility in Greenville, SC.

“We produce a lot of products,” Chris Tomaszewski, supervisor of laser operations and a 17-year employee, said. The company still serves the railroad industry, producing a complete line of braking products for freight trains, as well as components for passenger cars and commercial vehicles.

Major Investigation

“As a company, we started investigating lasers about 10 years ago,” Tomaszewski said. He supervises laser operations as well as performs laser programming. Producing a belly-mounted slack adjuster – a pneumatic brake-like mechanism that keeps rail cars tightly together and evenly spaced – prompted Ellcon-National’s investigation of lasers.

The adjuster’s main component is a 3.58" diameter steel tube, about 55" long, with 0.188" wall thickness. Before the introduction of the laser equipment, Ellcon-National’s production process for the part consisted of nine different operations on mechanical and pneumatic punch presses with five different die changes.

“Making 600 units a week took four guys working 60-hour weeks,” Tomaszewski said.

Increasing demand for belly-mounted slack adjusters forced the company to look for faster and better production methods. Plasma cutting would eliminate the dies and punches needed in punch press operations, but the cut quality wasn’t good enough. Waterjet cutting was considered, but deemed too expensive and lacked a reliable rotational axis.

“We needed 6th-axis capability, not only for processing tube, but also for other products that required angled or beveled cuts,” Tomaszewski said.

Ellcon investigators determined laser cutting was the best fit for the company’s needs. The initial purchase was a 2D laser-cutting machine with shuttle table and tube-cutting options. To meet Ellcon’s cutting needs, the supplier wrote a custom program for its machine.

Adding Another Laser

By 2005, Ellcon was looking for another laser to meet increased production. The company purchased a 2,500W Space Gear U44 system from Mazak Optonics, Schaumburg, IL.

“The rotational C-axis was there, and the 6th-axis capability eliminated bandsaw operations for other brake products, and parts in general,” Tomaszewski said.

The Space Gear U44 does 2D plate laser-cutting and 3D part processing. The compact cutting head designed for 3D workpieces minimizes interference and provides high-speed cutting in corners and pipe processing. Only three program lines are required for simultaneous 6-axis processing, such as cutting tight-fitting joints in square or round tubes.

The 2,500W CO2 laser cuts different materials and thicknesses without changing lenses or nozzles. Rapid-traverse rate is 945 ipm and maximum cutting feed rate is 591 ipm.

Laser cutting offers speed and accuracy compared to Ellcon-National’s punch press operations

Demand for Ellcon-National’s products continues strong, and efficiency of the Space Gear U44 has increased capacity. For belly-mounted slack adjusters, what took four operators, working 60-hour weeks on multiple punch presses, is accomplished by one laser operator in a 40-hour week.

Better Tolerances

“Tolerances are tighter on a lot of our products because of the laser’s precision,” Tomaszewski said. “We robotically weld a lot of parts, and the weld prep quality is better. We don’t have to grind any broken edges. We regularly hold ±0.005" accuracy.”

Responsible for laser programming, Tomaszewski also appreciates the laser’s CNC.

Because Ellcon-National is a big bulk-steel user, the speed and efficiency of laser cutting and programming has direct benefits.

“On a regular day, we go through up to 400 tubes. In an average month, we cut up to 40 3/8" sheets and up to 100 seven-gauge sheets,” Tomaszewski said.

Despite the workload, there is still capacity available in the company’s laser cutter.

“We’re making parts out of cutouts generated on our other machine,” Tomaszewski said. “For instance, if we have a 10" round dropping out of the nest on our other machine, with the nozzle-start capabilities on the Mazak, we’re making parts out of material already written off on another job.” Mazak Optonics

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