Porsche

Porsche differential housings machined with PCD

Unlike with many other applications, in the machining of the differential housing of the Porsche 911 turbo and the fourwheel drive model, PCD tools are used not only for finishing, but in some operations also for roughing.

In addition to considerable advantages in terms of tool life and machining speed, these have also resulted in cost savings due to a considerably reduced tool flow. Therefore, in roughing as well, the more expensive PCD tools are an economic alternative to other tool materials. 

In order to minimise tool flow, PCD tools (pictured above) with removable indexable inserts of the same PCD specification are used both for roughing and finishing.
Rotational speeds of 7,000 rpm and feeds of 0.14 mm/rev are used for roughing these bores, and finishing is performed at rotational speeds of 6,000 rpm and feeds of 0.21 mm/rev. The speeds used here, which are relatively low for PCD tools, ensure that the high requirements on the roundness of the H7 bores can be adhered to in a reliable process. Also, with an Rz of 8 µm the surface quality achieved is considerably better than that required by the customer (Rz = 10µm).

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