Flat parts pivotal to winning large contract
CINCINNATI, Ohio – "We used to cringe when we had a customer requirement for really flat parts." That's how Joe Arceneaux, manufacturing engineering manager at the Greensboro, North Carolina, plant of O'Neal Manufacturing Services (OMS), sums up his position at the time the company was competing for a long-term contract for construction machinery parts with a tight flatness spec.
OMS is one of the largest contract fabricators in the U.S., with 10 plants and 1,300 employees across the country. The ISO-certified, family-owned company has 139,300 m2 (1.5 million sq ft) of manufacturing space and is highly integrated to act as a partner for customers wanting to re-shore, outsource or rapidly develop new products and prototypes.
The Greensboro plant is located in an area with a concentration of construction equipment OEM's, so it is highly experienced in producing the large assemblies and components for excavators, paving equipment, etc. The contract requiring flat parts involved 10-mm-thick (0.39 in), laser-cut, HSLA steel with 65 ksi minimum yield (65,000 psi min. yield). The parts measure about 1 x 2.1 m (3 x 7 ft), and the customer requires 2 mm (0.07 in) flatness over the entire length. "This tough material has a lot of inherent stress in it to start with, so even if it is as flat as the mill can make it – which would still not meet the customer requirement – there will be distortion from stress relief during laser cutting," Arceneaux explains.
"We had a gantry flattening press we used for prototyping these parts and it took 15 to 60 minutes per piece, often requiring hits from both sides, and the parts are large enough to make material handling an issue in the process," Arceneaux explains. "We had seen ARKU's technology in Germany, and the customer and others have the machines, so we knew we had to 'level' the playing field to win this business. After processing several orders of prototypes through ARKU's Cincinnati leveling center, we purchased a FlatMaster 88 from the company's shop floor for immediate delivery in the spring of 2013."
The FlatMaster is specifically designed as a parts leveler to handle a wide variety of materials and thicknesses, as well as the variable requirements of processing different part shapes. It uses servo-hydraulics to set the leveling gap, maintain it and adjust forces to compensate for parts with cut-outs, perforations, or odd shapes, such as crescent or triangle. Servo-hydraulics also protect the machine from damage if it is accidentally overloaded. The leveling rollers can be changed and the unit thoroughly cleaned in minutes to avoid surface blemishes on parts, or contamination when running dissimilar metals. The FlatMaster 88 can process parts from 2 mm to 23 mm (0.080" to 0.910") thick, and widths up to 2 m (78.7"), depending on the model.
In addition to leveling, the FlatMaster also stress relieves the part. Level parts make it easier to setup and achieve consistent results with automated or robotic welding processes downstream. Stress relief ensures the parts don't warp during welding or bending.
The 85,000-pound FlatMaster required a foundation, but otherwise, "ARKU got the machine set up faster than the electricians could pull the power," Arceneaux adds. "We put the machine in line with our laser outfeed, where it's also accessible to the press brake. After a few days of training for our lead operator, we were ready to run. In a few seconds, one pass through the FlatMaster brings the part into spec and relieves inherent stress. As we look ahead at new business opportunities, we see the leveler as a competitive advantage for us. It is a real game-changer to have this capability in-house, because flat parts, fully stress-relieved, always improve downstream processes and quality."
Vice President Sales