Steel bonded carbide drill bit processing copper-nickel alloy, has a large advantage in cutting efficiency and tool life, but because of its strength is lower than the high-speed steel cutting tools, such as the use of a standard type of twist drill structure, can not be normal processing.
K value of 2.1 increases the thickness of the core drilling

National standards, coring per 100mm thickness K value increased 1.4 ~ 2.0mm, now changed to 100mm increases from 2.2 to 2.8 mm. Increase the thickness of the core drilling can increase the stiffness of drill cutting part.cutting wheel

2.2 reduce the helix angle β

National standards? 15mm twist drill helix angle b = 30 °, β = 25 ° now changed. Reduce the helix angle is conducive to sticky and hard chips discharged smoothly.

2.3 main cutting edge additional points of flute

Three crescent-shaped cross-out on the main cutting edge in two symmetrical 180 ° flute, to reduce axial cutting forces, and to create favorable conditions for chip removal.

2.4 to reduce the the edge bandwidth degrees f

National standards? 15mm twist drill blade width f = 1.0mm f = 0.75 mm, current decrease. Reducing the blade width can reduce the friction of the edge with the hole wall,grinding wheel  and reduce tool wear.

2.5 grinding chisel edge

Drilling the size of the axial force with the lateral edge of the size is closely related to reduce the cutting resistance, the chisel blade width was changed to 0.7 ~ 1.0mm (about 1/3 of the width of the chisel edge, the original).