Characteristics of deep hole drilling:
1. The tool holder is limited by the aperture, with a small diameter and a large length, resulting in poor rigidity and low strength. During cutting, it is prone to vibration, ripples, and taper, which affect the straightness and surface roughness of the deep hole.
2. When drilling and expanding holes, it is difficult to input cooling lubricant into the cutting area without using special devices, which reduces the durability of the tool and makes chip removal difficult.
3. In the process of deep hole machining, it is not possible to directly observe the cutting condition of the tool. Only by listening to the cutting sound, observing the chips, touching the vibration and workpiece temperature, and observing the instruments (oil pressure gauge and electric meter) based on work experience can we determine whether the cutting process is normal.
4. It is difficult to remove chips, and reliable methods must be used to break and control the length and shape of chips, in order to facilitate smooth removal and prevent chip blockage.
5. In order to ensure the smooth progress of deep hole machining and achieve the required machining quality, it is necessary to add chip removal devices inside (outside) the tool, tool guidance and support devices, and high-pressure cooling and lubrication devices.
Generally, a hole with a depth of more than 5 times of the hole diameter is called a deep hole. Its difficulty lies in chip removal and cooling. Fried Dough Twists drills can be used for holes with a relatively small hole depth. In order to remove chips smoothly, iron chips should be straight out in a thin strip shape and bring out smaller chips. At the same time, coolant is easy to enter.