Carbide drill can improve the service life and cutting speed of the tool, used for processing cast iron, insulation materials, glass and other brittle hard materials, can significantly improve the cutting efficiency. Especially for difficult materials such as high manganese steel, carbide drill bits must be selected for processing. However, when drilling general steel, due to the vibration and instability in the drilling process, the application of cemented carbide has been greatly limited, and this work needs further research and exploration.

At present, carbide drill bits are mainly made of Mosaic blades, that is, flat carbide blades are welded on the slotted cutter body. The most common percussion drill bit in life is this structure. The blade is commonly used YG8, the knife body is 9SiCr, and the hardness after handling is 50-56HRC. Figure 12-14 shows a carbide taper shank twist drill.

Compared with tool steel twist drill, the main structural features of carbide drill bits are:

1) The core of the tool body is thick, d=(0.25-0.3)D; In order to improve the stiffness and strength of the drill, reduce the drilling and strength, reduce the vibration during drilling, and prevent the blade cracking.

2) Add a tolerant chip groove so that the amount of chip removal will not be reduced after the drill core is increased.

3) The amount of inverted cone increases. The blade length is 0.01-1.08mm to reduce friction between the edge and the hole when drilling at high speed.

4) Generally made of double helix Angle. The front Angle of the hard alloy blade is small, and the spiral Angle is small w=6-38; In order to improve the chip removal conditions, the orientation part w-1520.