AEROSPACE MACHINING
5ME’s patented liquid nitrogen-based cryogenic technol- ogy allows LN2 to fl ow through the spindle and inside the tool just below the cutting edge, which provides optimum cooling. The reduction of temperature facilitates faster cut- ting speeds, which makes liquid nitrogen-based cryogenic machining ideal for tough-to-machine materials. The system is self-pressurized eliminating the need for pumps and other power-consuming assets. To ensure that critical components are not exposed to cryogenic temperatures, the feed system uses vacuum-jacket- ed insulated lines between the LN2 source and sub-cooler as well as to the spindle. The system feeds super-cooled (-321° F) liquid nitrogen at a prescribed pressure and fl ow rate for the specifi c tool and/ or application. The patented sub-cooler removes pressure- generated heat out of the system and condenses dual phase liquid nitrogen (liquid and gas) back to 100% liquid, preventing the formation of gases from downstream heat leaks and pressure drops. The integral Cryo Controller allows operators to program the fl ow rate to match require- ments of the application. The patented cryogenic machining system is easily retrofi tted to almost any OEM spindle, and has a variety of tool interfaces available. 5ME’s cryogenic tooling is specifi cally designed for the system and includes holders, turning and grooving tools, solid carbide mills and drills, indexable mills, drills, and boring tools. The new Okuma HMC with liquid nitrogen-based cryo- genic system will operate in Lockheed’s Dallas/Fort Worth production facility, and represents the collaborative efforts of 5ME, Okuma, Hartwig, and Lockheed Martin.
Tools Matched to High Heat Aero Materials Scott Daggett, national aerospace specialist, OSG USA Inc. (Glendale Heights, IL) said that a combination of the
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AdvancedManufacturing.org | February 2016
Rocket component benefi ts from multitasking processing on the shop’s Mazaks at LCP.
proper geometry, coatings that have higher oxidation tem- peratures and edge preps are among the key considerations to handle the high heat temperatures generated during the titanium machining process. “The higher the oxidation tem- perature of the coating, the better the chance of the tool suc- ceeding. A slight radius on the tool can not only protect the tools, but it also can help shear the material to keep it from increasing the heat generated. For OSG’s end mills, drills and taps, it is very important to have good substrates coupled with the right coating,” said Daggett. “We have many different tooling substrates, including HSS, HSS cobalt, pow- dered metal, carbide and micrograin carbides which from fi rst to last mentioned are increasingly hard and brittle. For example, when choosing a tool like a tap, generally speaking we don’t use carbide because it’s too brittle. We’re going to use materials like powdered metal or HSS or a combina- tion of HSS cobalt. On the other hand, for end mills and drills, tools that have to take a lot more abuse, we would use carbide,” said Daggett. In machining aerospace jet engine components where metals need to be light, but resistant to high heat, there are metals for the “cool” part and the “hot”
parts of the engine. “The cool part is where typically a lighter heat resistant material like titanium is used and the hot part is where the most heat is generated and you have to use nickel-based alloys that tend to be a little heavier and denser,” said Daggett. OSG offers cutting tools that can be used in jet engine machining and struc- tural parts machining. OSG’s EXOPRO UVX-Ni series of ultra premium end mills is designed to achieve stable performance in diffi cult-to-ma- chine materials such as Inconel 718. Its proprietary cutting edge geometry reduces cutting heat and forces, a variable
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