| 主权项 |
1. A multi-flute endmill comprising:
a cutting edge part having multiple cutting edges, each consisting of an end cutting edge formed on a tip side of a shank from a tool axis side to an outer peripheral side in a radial direction of the shank, a corner R edge that is continuous with the end cutting edge, and a peripheral cutting edge that is continuous with the corner R edge; and flutes formed between adjacent cutting edges in a rotation direction around the tool axis, wherein a rake face of the cutting edge is formed from a rake face of the end cutting edge from the tool axis side to the outer peripheral side of the shank, a rake face of the corner R edge is adjacent to the rake face of the end cutting edge and forms a surface different from the rake face of the end cutting edge, and a rake face of the peripheral cutting edge is adjacent to the rake face of the corner R edge and forms a surface different from both the rake face of the corner R edge and the rake face of the end cutting edge, the rake face of the peripheral cutting edge is positioned on a rearward side in the rotation direction R relative to the rake face of the end cutting edge, the rake face of the peripheral cutting edge is adjacent to the rake face of the corner R edge at an end on the corner R edge side and also serves as one flute face that constitutes the flute, and the rake face of the corner R edge is adjacent to the rake face of the end cutting edge at an end on the tool axis side, a gash that is in communication with the flute is formed between the rake face of the end cutting edge and a flank of an end cutting edge that is adjacent on a forward side thereof in the rotation direction, and the rake face of the end cutting edge also serves as one surface that constitutes the gash, the rake face of the end cutting edge and a gash face that opposes the rake face on the forward side in the rotation direction which constitute the gash create intersecting surfaces that respectively include different intersecting straight lines in the radial direction that pass through the tool axis O in a cross-section S1 that is orthogonal to the tool axis O, wherein the intersecting surfaces mutually form an angle φ in the rotation direction on the tool axis, at least the gash face forms a surface that is inclined toward the rearward side in the rotation direction from the tip to a middle of the shank relative to a flat surface including one of the straight lines in the radial direction that passes through the tool axis, the flute is formed from the rake face of the peripheral cutting edge that also serves as one flute face and a flute face that opposes the rake face of the peripheral cutting edge on the forward side in the rotation direction, the flute face that opposes the rake face of the peripheral cutting edge is inclined relative to the gash face toward the forward side in the rotation direction from the inner peripheral side in the radial direction to the outer peripheral side in the radial direction of the cutting edge part and inclined toward the rearward side in the rotation direction from the tip to the middle of the cutting edge part, the flute has a groove having an inner end toward the tool axis, and the gash has a groove having an outer end toward the outer peripheral side, the inner end of the groove of the flute is positioned more toward the rearward side in the rotation direction, than the outer end of the groove of the gash is positioned with respect to the rearward side, and in the radial direction, the inner end of the groove of the flute is closer to the tool axis, than the outer end of the groove of the gash is to the tool axis. |
