Figure A shows a cross-section of a drill bit in a hole being drilled. The pink colour shows the area of the drill bit and the blue colour shows the chip space of the drill bit (the space from which all the chips produced during drilling need to exit). The difficulty with drilling is that to increase the efficiency of the process, the force on the drill bit increases, which means that the area of the pink bit needs to be increased: but at the same time, increased drilling efficiency means that the amount of swarf produced increases, and the drill bit needs a larger chip space in blue. In drilling a fixed-diameter hole, the sum of the pink bit cross-section and the area of the chip space in blue will always be equal to the area of the hole, and the fact that they cannot both be increased at the same time is It is obvious that the two cannot be increased at the same time.
The challenge is how to improve drilling efficiency by increasing the pink cross-section of the drill while still ensuring that the increased amount of chips can be discharged smoothly. It is also a challenge to increase the chip evacuation space while maintaining the strength of the drill bit. This issue will be mentioned later in this book when talking about the selection of drill bits, so I would like to remind the readers of this in advance.
