The food we eat is safe partly because of what Mechanical Engineer Adolfo Edgar does at work. He designs mostly customized machines for Macro Engineering, which process the millimeter-thick plastic film that keeps fresh foods from perishing.
Processing the film for use by food packers requires winding it into rolls. "Some rolls weigh more than 5,000 lbs.," says Edgar. Rolls up to 110 feet wide and 40 inches in diameter rotate at speeds of 3,000 feet per minute, so the strength and durability of all machine parts is critical to their successful operation.
In the roll's core is an air shaft from Nim-Cor (Nashua, NH) that must bear the heavy weight of the rolled plastic. "Rolling a good roll of film requires as little bending of the roll's core and the air shaft as possible," explains Edgar. "The deflection tolerances must be very low."
The Nim-Cor shaft uses a patented gripping technology with independent flanges that provide equal pressure at all contact points in the roll's core. "When the air shaft inflates with air, it expands and equally distributes the gripping torque on the core," say Jerry Theriault, a senior engineer at Nim-Cor. "The air shaft works even if there are irregularities on the inside of the core."
Macro Engineering's customers are happy—stronger shafts on the machines translate into bigger rolls of film. Bigger roles of film require changing less often.
Nim-Cor manufactures the air shafts from steel, aluminum, or a carbon fiber composite. The shafts have quick-change inserts that accommodate plastic, paper and fiber cores with various core widths.
For more information about air shafts from Nim-Cor: Enter 537