Abstract: A monitoring device of a main spindle rotation speed in a machine tool displays a variation state of the rotation speed by a rotation speed variation unit using a display unit in the machine tool. The monitoring device includes a variation value setting unit, a drawing unit, a first display unit, and a settable range calculating unit. The settable range calculating unit is configured to calculate a settable range of a variation amplitude and a variation cycle based on a calculation formula. The calculation formula includes the variation cycle, a difference between a first rotation speed and a second rotation speed at mutually different timings among the rotation speeds varied relative to a reference rotation speed, an inertia of a rotating body, a rated output of a motor that drives a main spindle, and a usage proportion to the rated output of the motor.

Abstract: A monitoring device of a main spindle rotation speed in a machine tool displays a variation state of the rotation speed by a rotation speed variation unit using a display unit in the machine tool. The monitoring device includes a drawing unit, a variation position display unit, and a reduction effect index display unit. The drawing unit is configured to display a variation diagram that illustrates a relationship between a variation amplitude and a variation cycle of the rotation speed. The reduction effect index display unit is configured to display a reduction effect index on the variation diagram. The reduction effect index represents a reduction effect of chatter vibration. The reduction effect index is calculated based on a speed ratio that is a ratio of a rotation speed of one rotation before to a rotation speed at an identical rotation position of the main spindle at any given timing.

Abstract: A monitoring device of a main spindle rotation speed in a machine tool displays a variation state of the rotation speed by a rotation speed variation unit using a display unit in the machine tool. The monitoring device includes a drawing unit, a variation position display unit, and a reduction effect index display unit. The drawing unit is configured to display a variation diagram that illustrates a relationship between a variation amplitude and a variation cycle of the rotation speed. The reduction effect index display unit is configured to display a reduction effect index on the variation diagram. The reduction effect index represents a reduction effect of chatter vibration. The reduction effect index is calculated based on a speed ratio that is a ratio of a rotation speed of one rotation before to a rotation speed at an identical rotation position of the main spindle at any given timing.

Abstract: A monitoring device of a main spindle rotation speed in a machine tool displays a variation state of the rotation speed by a rotation speed variation unit using a display unit in the machine tool. The monitoring device includes a variation value setting unit, a drawing unit, a first display unit, and a settable range calculating unit. The settable range calculating unit is configured to calculate a settable range of a variation amplitude and a variation cycle based on a calculation formula. The calculation formula includes the variation cycle, a difference between a first rotation speed and a second rotation speed at mutually different timings among the rotation speeds varied relative to a reference rotation speed, an inertia of a rotating body, a rated output of a motor that drives a main spindle, and a usage proportion to the rated output of the motor.

Abstract: An end mill machining apparatus, a CAM apparatus, an NC program, and a machining method which suppress regenerative self-excited vibration and mode-coupling self-excited vibration. An end mill machining apparatus includes an end mill, and a control section for controlling the end mill. The ratio of the protrusion length of the end mill to the diameter of the end mill falls within a range of 5 to 50. The end mill is a variable pitch, uniform helix type or a variable helix type. The control section controls the end mill such that the contact angle between the end mill and a workpiece M1 during machining becomes equal to or smaller than a critical contact angle ?lim.

Abstract: An end mill machining apparatus, a CAM apparatus, an NC program, and a machining method which suppress regenerative self-excited vibration and mode-coupling self-excited vibration. An end mill machining apparatus includes an end mill, and a control section for controlling the end mill. The ratio of the protrusion length of the end mill to the diameter of the end mill falls within a range of 5 to 50. The end mill is a variable pitch, uniform helix type or a variable helix type. The control section controls the end mill such that the contact angle between the end mill and a workpiece M1 during machining becomes equal to or smaller than a critical contact angle ?lim.