Hitachi Industries Co., Ltd.

Hitachi, Ltd.

Tomu Kato

Hirotaka Kameya

Kazuhiro Matsumoto

Koji Utsumi

Hideaki Onozuka

A method for calculating depth of cut without any milling self-excited vibration. An initial value for machining-surface-perpendicular depth of cut is set. A cutting start angle and cutting end angle for a cutting edge is obtained, based on the initial value. A machining-surface-perpendicular depth of cut that causes no self-excited vibration is calculated. The maximum depth of cut that corresponds to the stability limit of a milling self-excited vibration is calculated, by repeating the calculation while modifying the initial value until the difference between the initial value and the calculation result becomes the same as, or smaller than, a given value. As a result, the stability-limit depth of cut is preliminarily analyzed to the milling self-excited vibration in consideration of a pick feed, the gradient angle of a workpiece, and a machining-surface curvature radius, so that man-hours required for creation and modification of NC data can be reduced.

Method and program for calculating maximum depth of cut without self-excited vibration of cutting tool

A screw compressor comprises a casing, and a male and a female rotor formed with axially twisted screw grooves and accommodated in the casing, the both rotors being rotated by timing gears fixed to the respective rotors while a desired minute gap is kept therebetween, and a method of manufacturing rotors therefor. In the screw compressor, the male and female rotors formed with axially twisted screw grooves in the casing comprise concave stripes having a minute depth and provided on the respective screw grooves to extend along directions of twist thereof, and leakage of a compressed air is less to give a high compression efficiency.

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Tsuchiura, Japan

Tomu Kato