Bruce Vernyi
EDITOR-IN-CHIEF
[email protected]
One of the consistent themes at an Aerospace Symposium hosted last month by Kennametal was how hard it is to cut the exotic alloys that are being designated for use in airframes and engine parts.
The alloys — primarily of titanium — are harder than Ti 6-4 and, in fact, approach the hardness of cutting tool materials. Engineers at The Boeing Co. and its suppliers are flummoxed; they are searching for solutions.
At the symposium — attended by about 200 people at a hotel in Westlake Village, Calif.— Mike Watts, an associate technical fellow for material and process technology for Boeing Commercial Airplanes, said our ability to machine hard materials has reached a plateau.
Boeing, of course, is the leader in designating titanium for aerospace use, and it's in a tough spot: Its new 787 Dreamliner promises such benefits as a 20 percent reduction in operating costs and greatly increased comfort for passengers. But those promises are based on expanding the use of composites and titanium alloys.
Watts showed a slide that traced advances in cutting hard materials through the 20th century, from the development of carbide cutting tools to multi-axis machining. The slide was based on the maximum material-removal rate for machining titanium, and it was plotted over time. It showed that, after the development of carbide tooling, most cutting advances made in the latter part of the last century were on the machine tool side. The slide also had spikes that showed advances in tooling, including the use of polycrystalline diamonds and the chemical vapor deposition technology used to put polycrystalline diamond coatings onto substrates.
However, the slide clearly demonstrated that it's been a few years since there have been any significant advances in cutting hard materials.
Watts also said the huge increase in the use of titanium for Boeing's new jet is going to translate into large increases in Boeing's demand for machining work. Suppliers need to start planning now for how they will help the aerospace giant cope with its expected surge in this heavy machining.Overall, the situation represents two great opportunities:
The first lies in the fact that the world's leading aerospace company has more hard metal on its hands than it can cut, and the orders that are coming in for its new jet are increasing cutting demand on a geometric scale. So, if you have a shop that can cut titanium, or if you can develop the skills to do so, there is a lot of work piling up. That's the obvious opportunity.
The second one is tougher: Boeing — and later, its rival Airbus — will need to figure out how to cut materials that are almost as hard as the cutting tools. In some instances, tool life on Boeing jobs is as little as 45 minutes. The undesirable expense this represents is obvious.
So is the need for some kind of technology breakthrough. Will it be an advance in cutting materials comparable to the carbide revolution? Or some other leap in machining technology, such as higher pressure, or far colder coolants such as liquid nitrogen?
Will the solution be found in a materials research laboratory, at Boeing, or from a completely unexpected direction?
There are fortunes to be made.
