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Diamond makes manufacturing of cars less expensive

In mass production of the key industries high-tech materials are increasingly used which can only be cut economically with diamond-coated tools, e.g. with indexable cutting inserts. They are establishing themselves more and more for the machining of light metals in areas such as car manufacturing and mechanical engineering. With their nanocrystalline, extremely smooth, hard surfaces, they offer an economical alternative to other solutions and are already superior in some applications with regard to performance, quality and precision.

The automotive industry is taking off the pounds. Composite materials, aluminum-silicon, magnesium and other light metal alloys contribute to reduce vehicle weight and to make considerably better use of the energy available in fuel. But what helps protect the environment, resources and the pocketbook in practice, proves to be extremely „stubborn“ behind the scenes during machining.

CVD diamond in the passing lane

Diamond-coated tools go the whole nine yards, because diamond is extremely hard and abrasion-resistant, and is characterized by an excellent thermal conductivity. In addition, it is almost completely resistant to chemicals, i.e. it has little affinity to other substances and demonstrates little tendency to gum up. CVD diamond coatings can be applied to even complex, three-dimensional geometries. And the coatings also adhere well to a continually growing number of coatable carbides, even with high cobalt contents of up to twelve percent.

In combination with the smooth surface, diamond coatings therefore provide top performance and outstanding chip transport, even when cutting abrasive Al Si alloys from a silicon content of approximately seven percent. Adhesions are prevented, however the chip shape geometry remains unchanged, as the diamond coatings in the CVD process grow directly on the substrate surface, and as a result simulate the geometry. The highly abrasive electrode graphite also makes the use of conventional tools uneconomical. Diamond solutions are almost the only alternative here.

Fortunately, diamond-coated tools prove to be extremely economical, for example with indexable cutting inserts. Here the coating costs are not only distributed among several cutting edges, they can also be used with higher feed rates than their uncoated counterparts.

Outstanding results in practice

An application case for the use of aluminum alloys like AlSi9 is car production, in order, for example to ensure stability for heavily loaded engine elements, but above all to reduce weight. Despite the high silicon content of the aluminum alloys used, it’s no problem for diamond-coated indexable cutting inserts.

During flat milling of cylinder heads, for example, the tool life was extended with a considerably increased feed rate using the CVD diamond multilayer matched to the application. This resulted in a productivity increase of 15 percent; the tooling and machine costs dropped both compared to uncoated and relative to PKD-equipped indexable cutting inserts. The result: diamond coatings are on the advance.

Source: FACTS 26 page 3-4