Wednesday, January 23, 2013

Laser Additive Manufacturing takes center stage

Well, the Super Bowl is set, and fans in New England and the Southeast are bemoaning a dropped pass here and a missed tackle there, as the Brothers Bowl promises an extra reason to watch San Francisco take on Baltimore in New Orleans. I’ll confess to being a 49ers fan since I was a lad, recalling grainy film on black and white television of YA Title, then a 49er, valiantly leading his team through the mud of Kezar Stadium. There was something exotic about the 49ers, playing on the West Coast that attracted an East Coast fan more attuned to Otto Graham and the Cleveland Browns, another early favorite. A few years later, I had the occasion to visit Kezar, on another rainy day, and I was so deflated by the dowdy, gray stadium that looked so like the old B & W images.

Now there’s a new era, and the 49ers are about to leave windy old Candlestick Park for new digs abuilding in Santa Clara, just down the 101. They are being led by one of a new generation of quarterbacks, one of at least three "option" quarterbacks who are revolutionizing the old NFL passing game. They are a feisty group: one looking like a lean tattooed hippy, another like a short fireplug, and the third resembling a dread-locked Alabama running back. The game they play is exciting and refreshing. In a league that is known for copycatting, it won't be long before this style is the norm.

All this brings to mind a more quiet revolution in laser materials processing technology and tangentially in lean manufacturing  around the world. Most metal manufacturing operations are subtractive with chunks of metal being machined down to final shape. Large amounts of scrap metal result, creating a new term "scrap management." Years ago I worked on a process that used a laser beam to cut the ribbons of metal resulting from turning operations into short pieces that could be blown into barrels for later recycling. These densely packed barrels freed up unproductive floor space in the machine shop and greatly reduced scrap management. However, it was judged too expensive because of the investment and operating cost of the lasers then used.

At about the same time, I was involved in a government-sponsored program to use the energy - in a focused or shaped laser beam impinging on the surface of hard-to-machine metal parts - just ahead of the cutting tool, which acted to soften the metal, leading to faster machining rates, less tool wear, and smoother finishes. 

The lasers we were using were also being used in a cladding process where layers of melted powder metals were laid down to create a new, more wear-resistant surface. We did play around with building up layers, but not to create a specific shape. Later, this technology was expanded at United Technologies as the laser beam melted and deposited metal to create an aircraft turbine component.

Others experimented with the buildup process and several limited-success activities evolved. Holding back more widespread acceptance of this process was the usual reluctance on the part of industry to accept change.

Early in the history of industrial lasers. the Brits had had the idea of cost-effective manufacturing of quantities-of one, but the concept never took root: too advanced for a slow-to-change industry. The evolution of "lean manufacturing" and the ideal of building quantities of one at a competitive price began to take hold several years ago. Some impetus came from the U.S. government, where the DOD sensed the future need for sources that could cope with the demand for replacement parts from industries that had long since stopped producing.

Sitting in the wings was the rapid prototyping industry that had expanded its capabilities into rapid manufacturing and was experimenting with deposition of metal powders to make useable parts. A conjunction of this technology with the needs of lean manufacturing and the availability of powerful cost-effective fiber laser sources created the process now known as additive manufacturing and its subset, laser additive manufacturing (LAM).

The Laser Institute of America recognized this technology as a process of the future and thus convened the first LAM conference in Houston last year. This year’s event, again held in Houston, will expand its frontiers beyond aerospace into the more mundane needs of small- to medium-sized machine shops. Interested parties, for a start, might consider attending LAM and joining the growing network of LAM enthusiasts.

ILS will feature articles on this subject, commencing with the March/April issue, where industry in the US is challenged to take up this technology. Like many technologies, its time has come, and the future is very bright for LAM.

1 comment:

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