Numerical control apparatus and control method fo machine tool

A control method of a machine tool comprising the steps of:

• preparing a machining program defining machining process of a workpiece by the machine tool provided with a cutting tool able to move in the directions of a plurality of control axes by a driving means,
• adding cutting/non-cutting information defining actual cutting by said cutting tool to a cutting feed command program included in said machining program,
• downloading the machining program added with the cutting/non-cutting information to a numerical control apparatus and executing said machining program,
• extracting at said numerical control apparatus, from said cutting feed command program, information for specifying a feed speed of said cutting tool to a workpiece and cutting/non-cutting information,
• calculating the permissible feed speed of said cutting tool in accordance with the content of the cutting/non-cutting information based on said information for specifying the feed speed of the cutting tool and optimizing the feed speed of the cutting tool to be within said permissible feed speed, and
• calculating control commands to be distributed to the control axes of the machine tool based on the optimized feed speed and controlling the control axes.

A control method of a machine tool provided with a numerical control apparatus for driving a machine tool to execute cutting of a workpiece in accordance with a machining program, comprising the steps of:

• preparing a machining program defining machining process of a workpiece by the machine tool,
• adding information of a permissible error defining a permissible range of error from a path of movement of a cutting tool to a cutting feed command program included in said machining program,
• downloading the machining program added with the information of the permissible error to a numerical control apparatus and executing said machining program,
• extracting at said numerical control apparatus, from said cutting feed command program, information for specifying a feed speed of said cutting tool to the workpiece and said information of the permissible error,
• calculating the permissible feed speed of said cutting tool in accordance with the permissible error based on said extracted information and optimizing the feed speed of the cutting tool to be within said permissible feed speed, and
• calculating control commands to be distributed to the control axes of the machine tool based on the optimized feed speed and controlling the control axes.

A control method of a machine tool provided with a numerical control apparatus for driving a machine tool to execute cutting of a workpiece in accordance with a machining program, comprising the steps of:

• preparing a machining program defining a machining process of a workpiece by the machine tool,
• adding predetermined machining information to a cutting feed command program included in said machining program,
• downloading the machining program added with the machining information to a numerical control apparatus and executing said machining program,
• extracting at said numerical control apparatus, from said cutting feed command program, information for specifying a feed speed of said cutting tool to a workpiece and said machining information,
• optimizing the feed speed of the cutting tool based on the extracted information, and
• calculating control commands to be distributed to the control axes of the machine tool based on the optimized feed speed and controlling the control axes.