Method of cutting off workpiece using band saw machine as well as band saw machine

Abstract

A method of cutting off a workpiece using a band saw blade. Chatter oscillation of the band saw blade is detected, the detected chatter oscillation is input to a pulse generator, and pulses based on the inputted chatter oscillation with a frequency not less than a characteristic frequency of a band saw blade supporting system are input from the pulse generator to the motor for imparting to one of the driving wheel and the driven wheel a forced longitudinal oscillation so that a phase of an oscillation the driving wheel along a rotational direction for the driving wheel is substantially inverted with respect to a phase of an oscillation of the driven wheel along a rotational direction of the driven wheel.

1 . A method of cutting off a workpiece using a band saw blade, the method comprising:
 cutting off a workpiece with an endless band saw blade suspended between a driving wheel and a driven wheel by a motor that drives one of the driving wheel and the driven wheel, wherein the workpiece is held by a vise device at a central position between the driving wheel and the driven wheel,   detecting a chatter oscillation of the band saw blade with a chatter oscillation detector,   inputting the detected chatter oscillation to a pulse generator, and   applying pulses based on the inputted chatter oscillation with a frequency not less than a characteristic frequency of a band saw blade supporting system, from the pulse generator to the motor, for imparting to one of the driving wheel and the driven wheel a forced longitudinal oscillation so that a phase of an oscillation of the driving wheel along a rotational direction of the driving wheel is substantially inverted with respect to a phase of an oscillation of the driven wheel along a rotational direction of the driven wheel,   wherein the band saw blade supporting system includes the driving wheel, the driven wheel and the band saw blade,   wherein the pulses are applied to the motor such that a ratio of an amplitude of the longitudinal oscillation which is imparted to the band saw blade near the driving wheel to an amplitude of the longitudinal oscillation which is imparted to the band saw blade near the driven wheel is approximately equal to one,   forming a node of the longitudinal oscillation at the central position between the driving wheel and the driven wheel, so that the detected chatter oscillation is blocked in a region where the node is formed,   thereby cutting off the workpiece with the endless band saw blade while the detected chatter oscillation is restrained.   
     
     
         2 . The method of cutting off a workpiece according to  claim 1 , further comprising:
 oscillating the band saw blade in a main-component-force direction by causing one of the driving wheel and the driven wheel to forcedly oscillate along its rotational direction so that the ratio between the amplitude of the oscillation is imparted to the band saw blade near the driving wheel and the amplitude of the oscillation which is imparted to the band saw blade near the driven wheel is approximately equal to one.   
     
     
         3 . A band saw machine which includes an endless band saw blade suspended between a driving wheel and a driven wheel, the band saw machine comprising:
 a vice device located at a central position between the driving wheel and the driven wheel, the vise device holding a workpiece,   a chatter oscillation detector configured to detect a chatter oscillation of the band saw blade,   a pulse generator electrically coupled to the chatter oscillation detector and configured to generate pulses based on the detected chatter oscillation; and   a motor which rotates the driving wheel,   wherein the pulses are applied to the motor from the pulse generator with a frequency not less than a characteristic frequency of a band saw blade supporting system which includes the driving wheel, the driven wheel and the band saw blade,   wherein the motor imparts a forced oscillation to the band saw blade so that a phase of an oscillation of the driving wheel along a rotational direction of the driving wheel is substantially inverted with respect to a phase of an oscillation of the driven wheel along a rotational direction of the driven wheel, and   wherein the pulses are applied to the motor such that a ratio of an amplitude of the oscillation which is imparted to the band saw blade along the rotational direction of the driving wheel to an amplitude of the oscillation which is imparted to the band saw blade along the rotational direction of the driven wheel is approximately equal to one,   wherein a node of the longitudinal oscillation is formed at the central position between the driving wheel and the driven wheel, so that the detected chatter oscillation is blocked in a region of the node,   thereby cutting off the workpiece with the endless band saw blade while the detected chatter oscillation is restrained.