Cutting method for inner circumferential face or outer circumferential face of work

A cutting method for an inner circumferential face or an outer circumferential face of a work using a cutting tool projecting from a main shaft which turns around a predetermined position serving as a turning center and for which a turning radius is adjustable, comprising the steps of:

• setting a table that supports the work in a rotating central axis that is coaxial with a turning central axis of the main shaft,
• rotating the table in a direction opposite to a turning direction of the main shaft to increase a cutting velocity of the cutting tool,
• increasing a total of a turning angular velocity of turning of the main shaft and a rotating angular velocity of the work with a decreasing distance from the turning center to a tip of the cutting tool, and
• in the case that the turning angular velocity of the main shaft is represented as ω1, the rotating angular velocity of the table is represented as ω2, the distance from the turning center to the tip of the cutting tool is represented as R, and a cutting velocity of the tip of the cutting tool is set to a constant value C, making the cutting velocity of the cutting tool constant by performing control such that ω1+ω2 changes in association with a change in the distance R so that
• ω
• 1
• +
• ω
• 2
• =
• (
• C
• 2
• -
• R
• .
• 2
• )
• 1
• 2
• /
• R
• is formulated where R denotes a time differential of the distance R.

A cutting method for an inner circumferential face or an outer circumferential face of a work using a cutting tool projecting from a main shaft which turns around a predetermined position serving as a turning center and for which a turning radius is adjustable, wherein a position of the turning center of the main shaft is not moved in an orthogonal direction nor an oblique direction, and comprising the steps of:

• setting a table that supports the work in a rotating central axis that is coaxial with a turning central axis of the main shaft,
• rotating the table in a direction opposite to a turning direction of the main shaft to increase a cutting velocity of the cutting tool, and
• forming a ring shape by the following steps:
• (1) in an inner region of the work that is close to the turning center, sequentially increasing the distance from the turning center to the tip of the cutting tool to move the tip along a helical locus, in the case that the distance reaches a maximum state, so that the maximum state is maintained to form an inner wall in a ring shape,
• (2) in an outer region of the work that is away from the turning center, sequentially reducing the distance from the turning center to the tip of the cutting tool to move the tip along a helical locus, in the case that the distance reaches a minimum state, so that the minimum state is maintained to form an outer wall in a ring shape.