The technological advances taking place in the aerospace manufacturing industry are enabling manufacturers to look beyond the physical limitations of yesterday's machining and towards tomorrow's possibilities. Although the basic concepts remain the same, a constant effort is made toward improving machining techniques and processes, thus reducing operational costs.

"We want to modify the traditional processes in an aim to reduce cost, waste and cycle time while maintaining high standards of accuracy. Waste control and accuracy are the two major concerns of the present-day industry," said Jerry Halley, an associate technical fellow of Boeing's Aircraft & Missile Division in St. Louis. "An emphasis remains on part accuracy because of the recent technological advances in the aerospace field that can affect assembly cost and time."

Highly accurate monolithic parts have significantly reduced assembly costs. However, they have also led to high levels of waste according to Halley, considered by many to be an innovator of high-speed machining in aerospace. "Aerospace manufacturers incur a significant loss in the transfer between raw material-to-finished product, and hopefully advances in our newest technology, near-net machining, will remedy the waste control problem while maintaining accuracy standards."

Near-net machining is the next era in aerospace manufacturing, and the offerings of this developing technology are numerous and desirable. The goal of this technology is to provide manufacturers the opportunity to create accurate parts from billets that are closest to the actual size of the finished product.

"The very aim of near-net technology is to eliminate unnecessary use of raw materials by creating a closer-to-actual-size part production," states Halley. "The associated obstacles of high-speed and thin-to-thin machining processes must be addressed to further advance the near-net machining concept."

Merging high-speed machining with the near-net process still presents a unique set of advantages and disadvantages, including chatter, part deflection and residual stresses.

Thin-to-thin machining is a very delicate process, and the production of parts from dimensionalized billets of raw material is quite troublesome. "Thin-to-thin machining is a very difficult process in which to maintain accuracy. Ultra thin, lightweight parts are very difficult to make from things that are already thin and lightweight," said Halley.

Still in its infancy stage, Halley notes that near-net possibilities have become more realistic for the aerospace industry-in terms of cost efficiency and capability, over the recent years.

Monolithic production allows machinists to work more exclusively with the core of the billets, greatly reducing impurities because of the core material traits. Also, the obvious advantages of fewer assemblies are reductions in machining time spent on a piece of equipment and less wasted material.

"Don't confuse our limitations with near-net machining with a disinterest in this new technology," adds Halley. "The aerospace field views near-net machining as one of the next steps toward the future of airplane manufacturing in a more accurate and cost-effective manner."

Near-net machining could prove to be the solution to even more advancement in driving out operation costs in aerospace manufacturing.

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