Machine Tool and Workpiece Machining Method

摘要

A machine tool includes a spindle retaining a tool, a spindle motor, a feed device relatively moving a workpiece and a tool with a feed motor, a spindle motor control unit, and a feed motor control unit. The spindle motor control unit continuously varies a rotational speed of the spindle in a periodic or non-periodic manner with a predetermined amplitude with respect to a target rotational speed. The feed motor control unit controls the feed motor in synchronization with the control of the spindle motor to continuously vary a relative moving speed between the tool and the workpiece such that a ratio of the rotational speed of the spindle to the moving speed does not become constant at least in a predetermined time zone in which a spindle speed reaches a maximal value and a predetermined time zone in which the spindle speed reaches a minimal value.

主权项

1. A method of machining a workpiece with a machine tool, comprising:
retaining a tool on a spindle; rotating the spindle at a target rotational speed; and relatively moving the workpiece and the tool at a target moving speed to a target moving position in a cutting feed direction, wherein:
a rotational speed of the spindle is varied in a waveform having a predetermined amplitude and continuously changing in a periodic or non-periodic manner with respect to the target rotational speed; anda relative moving speed between the tool and the workpiece is continuously varied in synchronization with the variation of the rotational speed of the spindle such that a ratio of the rotational speed of the spindle to the relative moving speed is not constant, at least in a predetermined time zone including a point where the rotational speed of the spindle reaches a maximal value and a predetermined time zone including a point where the rotational speed of the spindle reaches a minimal value.