| 摘要 |
FIELD: machine building.SUBSTANCE: drill includes a shank, a constricted part in the form of a flattened cone, which is spread to the shank, the base of which is arranged on the level of axial free end of drill. End of drill includes at least two main cutting edges connected by means of two central edges. Constricted part has two cutting edges and two grooves, which are arranged in turn and helically around longitudinal rotation axis of the drill. Each cutting edge includes a band, and each groove has the main cutting surface adjacent to the band and to the main cutting edge, which forms the intersection with the surface of the main rear angle on the level of axial free end of drill. Each band is continued radially to drill rotation axis with curved edge continued with the surface of the main rear angle so that intersection between each curved edge and adjacent groove is formed with an edge the radially external end of which has larger axial offset along drill rotation axis from its shank than the radial offset of inner end. Each of the above curved edges is continued on the side of surfaces of opposite scarves. Drilling method of holes by means of drills with the specified geometry is described.EFFECT: high-speed drilling of composite materials.18 cl, 5 dwg |
