Grinding standard of drill bit
Whether to have a good tool grinding standard is to measure whether a grinding center is professional standards. Standard of grinding, the general rules for different cutting tool in cutting different materials when the cutting edge of technology parameters, including the blade Angle, apex Angle, rake Angle, Angle, blade, after chamfering, etc parameters (in the , make the blade passivation process is called "blade".The process of chamfering the edge of an edge is called chamfering. Each professional company has its own years of summary and grinding standards.
Differences between HM bit and HSS bit
HSS bit: the top Angle is usually 118 degrees, sometimes more than 130 degrees. Sharp blade. The accuracy (edge height difference, symmetry, circumferential jump) is relatively low. Cross edges are modified in many ways.
HM bit: the top Angle is usually 140 degrees. Straight groove drills are usually 130 degrees, and three-edge drills are usually 150 degrees. Blade and edge (edge) are not sharp, often passivated, or called the edge and chamfering. High precision requirements. The cross blade is often shaped into an S- shape to facilitate chip breaking.
After the Angle:
The back Angle of the blade is very important for the tool. The back Angle is too big, the blade is weak and easy to jump, and it is easy to "prick". Back Angle is too small, the friction is too large, cutting disadvantage.
The back Angle of the cutting tool varies with the material being cut, the type of cutting tool and the diameter of the cutting tool. Generally speaking, the back Angle decreases with the increase of the tool diameter. In addition, the cutting material is hard, the back Angle is smaller, otherwise, the back Angle is larger.
