Deep drilling is drilling of bores with high depth to diameter ratio. Deep drilling with twist drills is problematic because of excentric bores. The advancement of technology has made it possible to achieve large depths of bores at smaller diameters and in shorter times. Dedicated machines make it possible to drill more centric bores with higher quality. Downside of dedicated machines is high cost. We calculated machine hour rate and found out, dedicated machine hour rate is 30% higher. We conclude, the results would be more representative, if we dealt with piece with more than one bore.
|