| Popis: |
Chip control is mandatory for automated turning operations. Machining of cast aluminium alloys with high Silicon content challenges conventional cemented carbide inserts. Polycrystalline diamond (PCD) inserts are alternatives to improve tool lives, even though chip breakers are challenging to produce and relatively few options are made available by tool manufacturers. This research consists of machinability studies, under dry longitudinal turning, performed for the AlSi9Cu3 aluminium alloy, produced by permanent mould casting process. The influence of different chip breaker geometries of PCD cutting inserts on cutting forces, power consumption, specific cutting pressure, chip shape and surface roughness is evaluated. Besides two chip breaker geometries (finishing and roughing geometries), a flat rake face insert is also considered. Generally, the flat rake face insert resulted in long chips (e.g. ribbon chips) for the tested conditions. The tested chip breaker geometries were effective in controlling the chip geometry for the range of recommended cutting parameters. In general, the cutting forces increase with the use of chip breaker as compared to the flat rake insert. However, the use of the roughing chip breaker for roughing cutting conditions resulted in lower cutting forces/power consumption which demonstrates the optimization of the chip breaker geometry for such operation. |
