| Abstract Scope |
The present study was performed on an Al-6% Cu-0.7%Si alloy, and 319 and 356 alloys following different heat treatments. The main task was to evaluate the drilling and tapping characteristics of the Al-Cu alloy with respect to the Al-Si based 319 and 356 alloys. The drilling work was carried out on a Huron K2X8five CNC machine at 15,000rpm with continuous cooling to absorb the heat and to clean the holes from the chips formed during the drilling operation. The results show that addition of Si coupled with T6 aging treatment produces the highest cutting forces (about 360N) among the alloys studied (approximately 270N) after 2500 holes. Considering the Al-Cu based alloys, varying the aging treatment has practically no significant bearing on the cutting forces. Apparently, a high Cu content acts as a self-lubricant, facilitating the drilling process up to 2700 holes, with no sign of tool wear. However, due to the low level of Si in the Al-Cu based alloy, built up edge (BUE) is more frequent, with conical chips, which would affect the precision of the size of the drilled hole. The chips are normally dull and characterized by their rough surfaces compared to those obtained from A356.0 alloy. |