How do the front and back angles of the drill change? How does it affect drilling?
The drill rake sometimes do some changes, for example, in the drill brass material and an insulating plate material, easy to drill bar knife, the cutting edge of the drill to grind 0 degrees before the angle, so the bit will not tie the knife; in addition, some of the more hard materials in the drill bit, if it is before angle, cutting edge strength is not enough, high temperature generated when the drill cutting, easy to burn out or cutting edge jump edge, then the bit to grind out before the rake angle is 0 degrees, it is helpful to enhance the strength of the drill edge. Protect the cutting edge of the bit so that the drill can go smoothly.
The front angle of the drill is the angle of the spiral groove of the drill. It is generally unchanged. After the drill angle should change according to the situation of the processing hole; for example, when drilling, the drill bit at the outer edge of the general angle generally between 8~14 degrees, if you want to draw it by fossa, orifice chamfering drill, drill angle will be smaller, the cutting edge of the drill will be down, like this helps maintain a steady state of the drill bit, rowed out nest and chamfer to smooth, does not produce the phenomenon of polygon.
The front angle mainly affects the feed rate of the drill, which is determined by the hardness and abrasiveness of the metal.The rear angle mainly affects the cutting, cutting, the central axial force, reducing the force surface, so as to reduce wear.
