1. Main drilling features

1.1 Definition of the drilling process

The drilling process can be compared to turning and milling, but with the difference that the requirements in terms of forming and chip evacuation are more stringent for drilling. The deeper the hole, the more difficult it is to control the operation and evacuate the swarf. On the other hand, generally speaking, quality criteria are more stringent for deep holes, while short holes, being usually more frequent, require a higher rate of material removal for good machining profitability. This means that the differences between short-hole drilling and deep-hole drilling are not limited to the simple relationship between hole depth and diameter. The parameters just mentioned - chip evacuation, machining quality and material removal rate - explain...