The redesigned and rebuilt press is 86 ft tall, like the original (illustrated below), and occupies the same space. But, it represents the most advanced engineering standards now available in “a fatigue-endurable design,” according to Siempelkamp.
You know a landmark when you see one. Think, for example, of the Statue of Liberty. There is nothing else like it. It dominates its surroundings, and defines the activity around it. That sort of a landmark also fires the imaginations of the people in its presence. It fills them with pride, with a sense of who they are and of their purpose.
In both these ways Alcoa has such a landmark with its 50,000-ton forging press in Cleveland. The 12-stories-tall machine embodies the history of that operation, and now that it’s been rebuilt after a three-year, $100-million redesign program, the “50” is emblematic of the ingenuity of the designers, technicians, and operators Alcoa believes distinguish it as a manufacturer of critical parts.
“Our iconic press played an integral role in Alcoa’s rich history and will be an equally key component to our company’s future growth and success,” declared Alcoa Forgings and Extrusions president Eric V. Roegner at an inaugural event recently. “It is vital not only to our business, customers, and employees, but to the continued growth and stability of our manufacturing operations.”
The story of the press would be legendary even if it were not factual. Details recorded by the American Society of Mechanical Engineers, which designated the 50 as a National Historic Mechanical Engineering Landmark over 30 years ago, recall that a need for critical forging capability was deduced during World War II by Allied intelligence officers examining the impressive but lightweight monolithic structures found in downed German aircraft. After the war, the presses that produced those components were revealed, but the largest German press – a 30,000-ton machine — was seized by Soviet forces. That spurred the institution of the Defense Production Act and the establishment of U.S. Defense Dept.’s Heavy Press Program. With federal sponsorship, the Heavy Press Program built four machines in order to produce the components needed for an adequate air-defense program through the Cold War period. Two of those presses — the 50 and its companion, the 35,000-ton press, comprising “Air Force Plant 47” — were installed at the Cleveland Works, with Alcoa as the prime contractor.
The 50 was built by Mesta Machine Co. in West Homestead, PA, and inaugurated in May 1955. Twenty-four massive steel castings framed a structure 87 feet from the base to the peak, with two “stools” carrying two lower base sections and two upper base sections. The 1226-ft movable die table holding the lower forging die was attached to the base sections. The maximum press stroke was six feet. Hydro-pneumatics (water and a small volume of soluble oil) were used to generate 4,500 psi of pressure from eight cylinders, to generate the 50,000 tons of force that gave the press its name.
Eight forged steel columns framed the structure, which Roegner recently credited as a remarkable example of mechanical engineering “before the entire science of fracture mechanics even existed, before finite element analysis, and particularly before the very advanced statistical sampling and modeling tools available now.
“Using their slide rules and tables they figured out what they thought would be the ‘life’ of the press,” he explained, adding that they were impressively close to identifying the failure limits of the original press.
Of course, it was a failure that set the current story in progress. In the third quarter of 2008, a series of cracks was discovered in the base castings of the press. This was not a complete surprise — Roegner reported that a crack had been found in one of the columns the 1970s, and the press had been disassembled and rebuilt with new columns in keeping with then-current structural engineering — but given the financial chaos of late 2008, and particularly the decline in aluminum prices, it presented Alcoa with what might have been an existential crisis. Not repairing the 50 was never a consideration, to the great relief of many defense and commercial aerospace customers, but something had to be done to restore this landmark piece of production equipment.
Roegner outlined the choices that Alcoa faced: “There were options we considered,” he began. “Patch it together: there are things you can do with a casting to drill, weld, stitch, reinforce, bracket, all that stuff,” he began.
“Start over, and build something completely from scratch,” he continued, “or, leverage everything we have here, but redesign and enhance what we have.”