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Old Meets New in Manufacturing

By: Louis A. Kren

Thursday, April 19, 2018
 

As the editor of a forging-industry magazine in the late-1990s, I was fortunate enough to see behemoth machines use brute force to shape metal alloys into locomotive crankshafts, aircraft bulkheads and other impressive parts. Often responsible for producing such products, massive forging presses dotted the U.S. landscape after World War II. These machines were constructed as part of the Heavy Press Program, a U.S. government effort to replicate huge forging presses used in Germany during the war. When hostilities ceased, the United States claimed two of Germany’s largest, but the grand-daddy, a 30,000-ton monster, was seized by the Russians. Unwilling to fall behind the Soviet Union in such important production technology and power, program officials chose Cleveland, OH, as the home for a new 50,000-ton press. Upon its completion, Alcoa operated the press, and does so today as Arconic.

Why write about giant forging presses in a magazine that covers metal additive manufacturing (AM)? Two reasons. For one, the Heavy Press Program offers a riveting Cold War tale–look it up and see what I mean. Secondly, that huge Arconic forging press helps illustrate the unique position assumed by metal AM in our manufacturing world. 3D printing has taken hold, from garage tinkerers to the largest global product producers, and far from a threat to traditional manufacturing, it’s serving as quite the complementary process.

We detail Arconic’s metal-AM efforts beginning on page 33 in this issue of 3D Metal Printing. I’ve always considered the company—employing its heavy machinery to pound out big parts in heavy, noisy, glowing (from furnaces and preheated billets) industrial settings–as the pinnacle of raw manufacturing might. Thus its AM path–with low noise and clean, contained production environments—at first seemed surprising. But upon reflection, it’s no surprise at all.

“We are metallurgists,” Ed Colvin, Arconic vice president of technology, told me. At its core, the company’s business is to understand intimately material properties and behaviors, and at given temperatures give those materials 3D shapes. Where traditional processes and AM differ most is where Arconic has been focusing R&D.

“With traditional methods such as forging or casting, we deal with metal alloys cooling from liquid fairly slowly into a solid,” explains Don Larsen, Arconic’s vice president of R&D for advanced manufacturing and advanced powders. “However, with 3D printing, we need to understand the evolution of the microstructure as it cools very quickly from a molten to a solid state.”

The effects of rapid cooling, from microscopic layer to layer to layer, influence the quality and performance of AM parts. On top of that, the effects must be documented and qualified to meet stringent aerospace requirements. It’s century-plus experience in developing alloys, shaping them and then backing results with data allows Arconic to flatten its learning curve with AM. Only about three years on with metal-AM production, via laser-powder-bed and high-deposition-rate processes, the company already has seen its 3D-printed parts fly on production commercial jets and spacecraft. And, Arconic has teamed metal AM with its longtime forging expertise to unveil the material-, time- and cost-saving Ampliforge process, where 3D-printed preforms are hammered and pressed into final parts.

True enough, 3D metal printing complements the company’s traditional processes and defines a new, yet familiar, path forward, enabling Arconic to employ its metallurgical and process expertise in unique ways.

The pages of 3DMP have documented not only the new entries on the manufacturing scene, but also the longtime players such as Caterpillar, General Electric have parleyed decades of experience into metal-AM success. Arconic is another, and its breadth of manufacturing prowess, from 50,000-ton ageless presses to clean-room additive machines, is, to borrow a forging term, striking.

 


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