DRY MACHINING ALUMINUM ALLOYS

Engineers from Sumitomo Electric Industries, Ltd. have developed an advanced Diamond-Like Carbon Coating (DLC) for the dry machining of aluminum alloys and non-ferrous applications.

Previously, in the first stages of harsh-environment cutting, coatings would peel and lose their beneficial properties. Now, with advanced DLC, cutting tools effectively maintain their properties, including high hardness, excellent lubrication, very low friction coefficient, very smooth surface, corrosive resistance and longer tool life.

Diamond-like carbon (DLC) film is a unique, amorphous hard thin film whose main composition is carbon. It features high-hardness, superior tribology properties, and excellent adhesion resistance. In the past, investigation had been carried out to exploit these features to cutting tools. But because the DLC film lacked the adhesiveness required in the hard environment of cutting tools, the film peeled off at the early stage of cutting process and the tool could not exercise its full potential.

However, from the viewpoint of global environment protection, the demand for dry cutting that does not require cutting fluid is becoming overwhelming. Because DLC film achieves a low friction coefficient without lubricant, it is now seen as a promising alternative technology for cutting oil.

The engineers have succeeded in developing a high-adhesion DLC film (Aurora Coat) that is applicable to cutting tools. When this newly developed DLC film is applied to cutting tools for aluminum cutting (inserts, endmills, and drills), the tools show excellent cutting properties in both dry cutting and semi-dry cutting. These research findings and more and can be found in ?Development of DLC Coating Film (Aurora Coat) and its Application to Tools.?

The DLC coating promotes good chip control and has a low friction coefficient of µ = 0.05 ? 0.2, even without lubricants. Aluminum alloy adhesion on the edge is suppressed even in dry machining, thereby decreasing cutting resistance. Furthermore, generation of built-up edge is suppressed, thereby maintaining the sharpness of the edge and improving the quality of the cutting material. Chips are removed effectively, preventing the cutting material from being scratched by chips and preventing deterioration of the machined surface caused by re-adhesion to the cutting material.

This advanced DLC coating can be found on Sumitomo carbide grades, drills, and endmills.

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Sumitomo Electric Carbide, Inc., 1001 Business Center Drive, Mount Prospect, IL 60056, 800-950-5202, Fax: 847-635-9335, www.sumicarbide.com.