Monday, September 15, 2008

Machining aluminium alloys

Undoubtedly this kind of machining is close to the physical high speed concept, since cutting speeds can reach a value of 2000 m/min, or higher when using milling plates whose diameters exceed 50 mm. At this speed chip generation is different from conventional, mainly because almost all the heat generated by the deformation energy inherent in the chipping process is evacuated with the same, which is highly positive for both tool and part.

We could say lightweight alloys is the most traditional field of high speed machining, known since the 1970s and applied to the fuselage component machining sector. In fact the first systematic HSM studies were in the aeronautical field.In the case of aluminium alloys, there are two different cases as per alloy type:

- Aeronautical alloys, particularly the 2000 or 7000 series, called malleable or wrougth. Easily machinable, used in component construction obtained by eliminating a large amount of chips from an initial prismatic block. A small component example is shown in Fig. 5 (left).

- Cast alloys (series 3xx), used mainly in car engines (blocks and pistons), are highly abrasive because they contain silica. The typical operation is planing and finish of a cast part very similar to the final one, with little chip volume. An example is the block shown in Fig.

Airframe component. Aluminium Aluminium engine block.

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