Dry goods, the relationship between

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سُئل أكتوبر 21 في تصنيف تفسير الاحلام بواسطة Elias (260 نقاط)

Original title: Dry goods, the relationship between geometric angle of twist drill and sharpening accuracy Source: Mechanical Professor Geometric angle of twist drill: 1. Vertex angle 2 Φ It is the angle between the projections of the two main cutting edges in the midplane. The smaller the vertex angle is, the longer the main cutting edge is, the load on the unit cutting edge is reduced, and the axial force is reduced, which is beneficial to the axial stability of the drill. And the tool tip angle at the excircle is increased, thereby being beneficial to heat dissipation and improving the durability of the tool. However, the decrease of the vertex angle will weaken the strength of the drill point, increase the chip deformation, and lead to an increase in torque. A standard twist drill has a vertex angle of about 118 °. HSS high speed steel drill: the top angle is generally 118 degrees, sometimes more than 130 degrees; HM carbide drill: the top angle is generally 140 degrees; straight flute drill is often 130 degrees, and three-edged drill is generally 150 degrees. 2. Front angle The angle between the rake face and the base plane in an orthogonal plane. The relationship between the rake angle of any selected point on the main cutting edge and the helix angle, cutting edge angle and cutting edge inclination angle of the point is tan = tan/sin + tancos (2-3). As the helix angle gradually decreases from the outer diameter to the drill center,dth rock bit, the cutting edge inclination angle also gradually decreases (negative value increases). When the cutting edge angle is constant, the rake angle decreases from + 30 ° to -30 °. The cutting condition near the center of the drill bit is very poor. 3. Rear angle The clearance angle at any point on the cutting edge is the angle between the cutting plane and the flank at that point. The relief angle of the drill is not measured in the main profile, but in the assumed working plane (feed profile). In the drilling process, it is this relief angle that actually plays a role, and it is also convenient to measure. The clearance angle of the drill bit is obtained by sharpening. During sharpening,Borehole Drill Bits, the outer edge of the drill bit shall be sharpened to a smaller angle (about 8 ° ~ 10 °), and the area near the drill center shall be sharpened to a larger angle (about 20 ° ~ 30 °). The reason for sharpening in this way is that the relief angle can be adapted to the change of the rake angle of the main cutting edge, so that the wedge ae between the projection of the main cutting edge on the base plane of the point and the drilling feed direction. Due to the different base planes of each point on the main cutting edge of the twist drill, the main deflection angle of each point also changes accordingly. After the twist drill is ground to a vertex angle of 2Φ, the main cutting angle of each point is determined, dhd drill bit ,down the hole bit, and the relationship between them is tan = tanΦcos (2-2). The end face cutting edge inclination angle of the selected point is the included angle between the projection of the main cutting edge in the end face and the base surface of the point. Expand the full text luntarily. Pithy formula 4: "Swing up and down and don't warp your tail." This action is also very important in the process of drill sharpening. Some students often change "swinging up and down" into "rotating up and down" when sharpening,mining dth bit, which destroys the other main edge of the drill. At the same time, the tail of the drill bit should not be higher than the horizontal center line of the grinding wheel, otherwise the cutting edge will be blunt and can not be cut. Return to Sohu to see more Responsible Editor:. wt-dthtools.com

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