The details of deep hole drilling process are not overlooked, and customers have high requirements for quality. What details should be paid attention to? 

1. Deep hole machining is in a closed or semi closed state, so the cutting condition of the tool cannot be directly observed. 

2. Cutting heat is not easily dissipated. During the general cutting process, 80% of the cutting heat is carried away by the chips, while in deep hole drilling, only 40% is carried away. The tool accounts for a large proportion of the cutting heat, with delayed diffusion and easy overheating. The temperature of the cutting edge can reach 600 degrees, and a forced and effective cooling method must be adopted. 

3. Chips are not easily discharged. Due to the depth of the hole, the path through which the chips pass is long, which can easily cause blockages and result in drill bit breakage. Therefore, the length and shape of the chips should be controlled, and mandatory chip removal should be carried out. 

4. The rigidity of the process system is poor. Due to the limitation of aperture size, the length to diameter ratio of the hole is relatively large, the drill rod is thin and long, the rigidity is poor, and it is prone to vibration and drilling deviation. Therefore, support and guidance are extremely important. 

In order to correctly guide the drill bit into the drill, it is usually done by machining guide holes on the workpiece or using guide sleeves. The former is used for single piece machining, while the latter is used for mass production.

The deep hole drilling error is caused by the gap between the drill bit and the guide sleeve (guide hole), and increases with the increase of axial force. The influence of the gap between the guide sleeve and the drill bit on the drilling error.

At the beginning of drilling, radial force presses the drill bit guide block against the wall of the guide sleeve hole. Due to the gap between the two, the center of the drill bit is offset relative to the center of rotation of the workpiece, and the drilled hole diameter is smaller than the drill bit diameter. When the guide block begins to enter the processed hole, under the action of the slightly smaller diameter hole wall, the outer blade is pushed outward, causing the center of the drill bit to shift in the opposite direction relative to the center of rotation of the workpiece, expanding the hole diameter, and rubbing against the guide hole wall, rapidly increasing the drilling torque.