Abstract: 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.

Abstract: There is provided a method for calculating depth of cut without any milling self-excited vibration, in consideration of a machining condition, the rigidity of a machining tool, the machinability of a material, and the like; in the method, an initial value for the machining-surface-perpendicular depth of cut is firstly set, by utilizing as input values the curvature radius of a machining surface, a tool radius, a pick feed, the gradient angle between the machining surface and a rotation axis of the tool, and the number of tool edges; a cutting start angle and a cutting end angle for a cutting edge is obtained, based on the initial value; the machining-surface-perpendicular depth of cut that causes no self-excited vibration is calculated; and 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

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.