In deep-hole drilling, small-diameter holes of less than 1 mm are machined using carbide gun drills, whereas holes of 15 mm and above are typically drilled using welded-edge drills, and holes of 25 mm and above are drilled efficiently using indexable-insert drills.

After all, compared to five-axis machining centres, three-axis machines have only three linear axes (X, Y and Z); their structure is simple, the tool axis does not change direction during machining, their range of motion is limited, and programming is relatively straightforward; whereas five-axis machining centres, on the face of it,

Furthermore, the widespread use of monolithic thin-walled structures and difficult-to-machine materials means that manufacturing processes are frequently hampered by bottlenecks such as long lead times, high material removal rates, low machining efficiency and significant machining deformation. In order to improve the machining efficiency and accuracy of complex aerospace components

Combined machining is currently one of the most widely used machining processes in the field of mechanical engineering worldwide. It is an advanced manufacturing technology. Combined turning and milling involves performing several different machining processes on a single machine tool.