In deep hole drilling, using a spot drill before the actual drilling can improve the straightness of the hole, reduce tool deviation, and enhance the quality of hole processing:
- Straightness of the Hole: Deep hole drilling often requires maintaining high straightness of the hole to ensure the correct alignment and functionality of machined parts. A spot drill can create a small pilot hole to guide the drill bit, reducing the chances of the drill wandering off the predetermined path, resulting in straighter holes.
- Tool Deviation: In deep hole drilling, due to cutting forces, material characteristics, and vibrations, long drill bits are more prone to deviation. By using a spot drill to create a pilot hole, additional support and guidance are provided to the drill bit, reducing the likelihood of tool deviation and ensuring better hole processing quality.
- Chip Evacuation: Deep hole drilling generates a significant amount of chips that need to be effectively evacuated to prevent cutting tool breakage or damage. The pilot hole drilled by the spot drill helps with smoother chip evacuation, achieving more efficient drilling.
- Cutting Tool Life: Processing a pilot hole with a spot drill can reduce the amount of material the drill bit needs to remove, thereby reducing the cutting forces acting on the drill bit. This helps to extend the life of the cutting tool and improve overall processing efficiency.
- Surface Roughness: By processing a pilot hole with a spot drill, drilling can achieve better surface roughness. The pilot hole guides the drill bit, ensuring a more consistent cutting process and smoother surface finish.