Amamco Tool 72dpi Proof

cutting tool solutions 1,500 to 3,500 MPa (carbon fiber alone is shown in the chart below) as compared to aluminum, at between 450-600 MPa and steel, at 750 to 1,500 MPa (MPa is a metric unit for pressure, or force per unit area). As for weight or density, carbon fiber-epoxy has been rated at a low 1.52.0 g/cm3, compared to aluminum at 2.76 and steel at a whopping 8.01.

Composites, each presenting a unique composition and set of characteristics, are competing with and replacing traditional building materials — steel and aluminum — at a rapid rate.

• PCD • CVD diamond coated tools The polycrystalline diamond tool is The Chemical Vapor Deposition (CVD) diamond coated tool is a solid a synthetic diamond product produced carbide tool coated by a protective by ultra-high pressure and heat applied diamond surface that extends up to 10 to a diamond powder mixed with a times its useful life cycle. Among the va- metal matrix binder. Selecting a tool solution There are basically two types of A tool’s cutting edge hardness and riety of coating processes, the preferred PCD tools. One uses a brazing process, (CVD) diamond coating was commergeometries are two critical factors to inserting a PCD blank into a groove cialized nearly 20 years ago for nonconsider when choosing the tool for that has been cut into a carbide tool your job. Of the two, correct geometry ferrous cutting tool applications. CVD body. is of primary importance because the diamond coating is a well-established The other uses a sintered vein proefficiency of a tool is determined by the technology for machining graphite and cess that bonds diamond powder and geometry of its cutting edge. hard carbon material. binder that is inserted into a groove CVD diamond along the carbide body. Heat and presMaterial Ultimate Density coatings consist strength (MPa) (g/cm³) sure are then applied to create the PCD of 100 percent Carbon Fiber 5,650 1.75 and at the same time bond it to the pure diamond Steel high strength alloy 760 7.8 carbide tool body. crystals that are Both PCD technologies produce Aluminum alloy 455 2.7 actually grown in diamond-hard cutting edges. HowValues depend on manufacturing process and purity/composition. a vacuum cham(Source: A.M. Howatson, P.G. Lund, and J.D. Todd, “Engineering Tables and ever, PCD geometries are limited ber using superData,” p.41) and their cost is comparatively quite heated filaments high due to an expensive and lengthy There are currently three tool choices to activate hydrogen and methane gasable to withstand the punishing hard- es. The resulting vapor mixture bonds manufacturing process. The unit cost ness of today’s composites. They are to the surface of tungsten carbide in of a PCD tool ranges from three to solid carbide, diamond coated carbide, thickness that is controlled within a five times the unit cost of a comContinued on page 34 and polycrystalline diamond (PCD). range of 3 to 30 microns. • Solid carbide tools Diamond coatings protect the An industry standard, the solid car- entire cutting surface of complex bide tool continues to be the most geometry tools. Unlike the cobalt widely used tool for machining com- binder used in making PCD tools, posites, as well as traditional materials. the chemically inert properties of It has been in use for over 50 years. diamond do not react with comWidely and readily available, this tool posite resins during machining. can accommodate the broadest range Increasingly, with the right tool of cutting geometries. geometries and recent advances in The low commodity price of carbide multi-layer coatings, even extremeallows operations to consume many ly abrasive composite materials are units before approaching the cost of being efficiently machined to exact using PCD tools. Additionally, the solid tolerances using diamond-coated carbide tool can be re-sharpened many solid carbide tools. times, further extending its effective life. A diamond coating on a solid Amamco diamond coated carbide Composite Drill carbide tool preserves the tool’s edge geomvs. PCD etry while protecting Overall Tooling Cost 97% Reduction the tool’s entire surSpan Time 75% Reduction face and can extend its Tool Life – Holes per Tool 450% Increase useful life by as much Floor personnel work on the fuselage of the Feed Rate 12 Times Faster F-35 fighter. as 10 times. www.ToolingAndProduction.com

January/February 2009

tooling& production

33

cutting tool solutions The CFRP strength ingredient, carbon fiber, is many times stronger than aluminum and even the hardest steel. petitive coated tool and as much as six to 10 times that of a non-coated carbide tool. The F-35 composite drill Lockheed Martin Aeronautics Co. manufactures major components for the F-35 Joint Strike Fighter, the next generation fighter jet being developed by the U.S. Department of Defense and eight other partner countries. As described below, the company achieved improved quality machining results in less time while significantly reducing total tool cost. When faced with a tooling change, testing at Lockheed revealed that precise cutting edge geometries allowed operators to greatly reduce span time and increased feed rates. The resulting tool and process change netted a 450 percent increase in the number of holes drilled per tool. After implementing the Amamco tool into the process program, test results showed the CVD diamond coated drill produced over 1,200 holes com-

pared to 275 produced by the PCD drill on the same task. Test results also showed a reduced span time of 75 percent and an increase in feed rates of 12 times faster than the original drill. In the aggregate, Lockheed achieved a 97 percent reduction in tool cost. The process change savings represent substantial cost reductions over the course of manufacturing the expected 2,783 F-35s planned for production. Solutions for composites Speeds and feeds play a major role in the performance of any cutting tool, especially when working with today’s advanced composites. Keeping thrust to a minimum can reduce heat and friction created at the cutting edge, as do protective coatings. Less heat and friction at the cutting edge will result in a longer tool life and a higher quality cutting edge or surface. CVD diamond coating, a true 100 percent diamond crystal, reduces heat and friction created by the highly abrasive composite environment and pro-

Construction continues as an F-35 takes shape. 34

tooling& production

January/February 2009

Some components are hand-fastened on the F-35.

tects the geometry advantages of the solid carbide tool. There are cases where each of the three tools described would be suitable and each has characteristics appropriate for the application you may be considering. Solid carbide will remain the tool standard for machining composites, and both PCD and CVD diamond coating solutions are increasingly available. Tool choice will likely continue to be based on budget and shop floor factors that are complex and often complicated by material availability and project schedules, beyond the control of production managers. However, tool performance and choice will increasingly be based on the two attributes determining a cutting tool’s effectiveness and efficiency: cutting edge geometry and hardness. Amamco Tool, www.rsleads. com/901tp-194; Lockheed Martin Aeronautics Co., www.rsleads.com/901tp-195 www.ToolingAndProduction.com