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Diamond Coatings reduce Costs

Diamond-coated tools have established themselves as standard in series car production. It's no wonder, as especially when machining abrasive materials, there's no getting around diamond. Compared to the conventional TiAlN coatings which have proven themselves in the past, the hardest known material clearly further improves performance. Impressive examples include the tools from TiroTool of Innsbruck, Austria. The drill bits and milling cutters provided with CemeCon diamond coatings reduce costs significantly in the respective applications when machining BMW crankcases of AlSi alloys.

Aluminum-silicon alloys are increasingly used in car manufacturing, as they have a much higher tensile strength than pure aluminum with a similarly low weight. To reduce weight, BMW, as a pioneer in this area, is taking a route very promising for the future in AlMg combination design for the basic engine. Due to the use of magnesium as a casing for an aluminum silicon insert in a crankcase, the machining tools are faced with difficult tasks. Cutting materials are required thatenable machining of these materials with a long tool life.

Diamond does the trick

CVD-diamond-coated tools are especially well-suited for this purpose. Diamond is particularly characterized by an enormous hardness, outstanding thermal conductivity and extreme resistance to abrasion. In addition, diamond is almost completely resistant to chemicals and has an almost negligible tendency to gum up. Diamond coatings like CemeCon Multilayer offer a broad range of possibilities in the coating of three-dimensional geometries. Together these positive properties result in an incredible power packet with which difficult materials can be machined economically.

Considerably fewer tool changes

The fact that real money can be saved in the process is impressively shown by the example of the TiroTool tools in the car production series coated with CemeCon diamond. Werner Heumader, CEO of TiroTool explains, “Due to the special geometry, less contact pressure is required during machining and the cutting capacity is improved. In conjunction with the diamond multilayer coating, considerably fewer tool changes are required to achieve top precision. That has an immediate effect on the costs.”

For example, when drilling AlSiXX. There the number of tool changes for the stepped drill bit used with emulsion cooling were reduced by 25 per cent compared to a TiAlN coated stepped drill bit. This means for BMW an enormous reduction of costs.

During emulsion-cooled milling of AlSiXX+ Mg of the BWM crankcase, a TiAlNcoated end milling cutter had to be changed 1.110 times a year up until now, however the diamond-coated TiroTool milling cutter just 133 times. Werner Heumader remarks, “In addition, we’ve also proposed a different milling strategy. Now the cutting forces no longer produce such heavy vibrations, which reduces the strain on the spindles.” The “productivity multiplier” diamond coating has also prevailed for the machining of crankcases of AlSi alloys.

Source: FACTS 25 page 5