Abstract
There were many studies on the machinability of aluminium alloys, but they treated mainly the machinability in turning and few in the fields of drilling. When the machinability on steel and iron is discussed, it is a way to emphasize the tool durabilty, but the problem is how to finish the drilling surface than the durability of the tool in aluminium alloys, and the machinability is rather affected by the creation of built-up edge in turning. Then, it is not cleared that whether the machinability in drilling has some similarity to that in turning or not.
In this paper, the machinability in drilling the aluminium-silicon cast alloys changing silicon contents from 1 to 30% was investigated and the effect of silicon to the machinability was to be considered. It seemed that the machinability in drilling had to be discussed several factors; the drilling resitance, the tool durability, the roughness of drilling surface, the chip formation, the chip disposal and others. The drilling resistance, the drilling time, the drilling surface and the chip formation were chiefly studied in this investigation. As the results, the machinability in drilling is better in the alloys of 8∼12% Si than any others.
This study owed its expenses to the Scholarship Committee of the Institute of Light Metal Foundation to which the authors express their thanks.
