Lathe, computer program for lathe control, and machining method by lathe

A program recording medium for use with a computer for executing instructions stored to said medium to perform a method, for controlling a lathe, the lathe being configured for cutting a work with a tool, the medium including instructions for the method comprising:

• a first cutting process of controlling the lathe to apply first cutting to said work and subsequent second cutting to said work while transferring said tool in an X axis direction;
• a calculation process of cutting of calculating an amount of deviation, along a Y-axis direction, different from said X-axis direction, between a cutting edge height of said tool and a center line of said work (W), based on a first diameter value of said work (W) after said first cutting is applied, a second diameter value of said work (W) after said second is applied, and a travel distance of said tool (41) in said X-axis direction from when said first cutting is finished until when said second cutting is finished;
• said first and second diameter values and said travel distance being input from an input unit of the lathe, and
• a second cutting process of controlling the lathe to apply third cutting to said work, after said amount of deviation is corrected.

A machining method by a lathe which cuts a work (W) by a tool (41), comprising:

• a first cutting step of applying first cutting to said work (W) while transferring said tool (41) in an X-axis direction;
• a first measuring step of measuring a first diameter value, which represents a diameter of said work (W) after said first cutting step:
• a second cutting step of applying second cutting to said work (W) while transferring said tool (41) in said X-axis direction after said first cutting step;
• a second measuring step of measuring a second diameter value, which represents a diameter of said work (W) after said second cutting step;
• a deviation amount calculating step of calculating an amount of deviation, along a Y-axis direction different from said X-axis direction, between a cutting edge height of said tool (41) and a center line of said work (W), based on said first diameter value, said second diameter value, and a travel distance of said tool (41) in said X-axis direction from when said first cutting step is finished until when said second cutting step is finished;
• and
• a third cutting step of applying third cutting to said work (W), after said amount of deviation is corrected.

A lathe, comprising:

• a main spindle (30) including a chuck for grasping a work (W) such that a center line of said work is in a Z-axis direction:
• a tool post configured for a tool for machining said work by abutting on said work, to be attached to said tool post;
• a tool post drive unit which transfers said tool post (40) in an X-axis direction, which is a direction extending from said tool (41) to said work (W) and is a direction different from said Z-axis direction, and in a Y-axis direction different from said X-axis direction and said Z-axis direction;
• a control unit which performs control to drive said tool post drive unit, such that said tool (41) is transferred in said X-axis direction and in said Y-axis direction;
• and
• an input unit for inputting a value of a diameter of said work (W) measured,
• wherein said control unit
• applies, via said tool post drive unit, first cutting to said work (W) and subsequently second cutting to said work (W) while transferring said tool (41), which is attached to said tool post (40), in said X-axis direction,
• calculates, as an amount of deviation, a distance along said Y-axis direction between an X-Z reference plane on which said center line of work exists and an abutting part of said tool (41) abutting on said work (W), based on a trigonometric relationship between a first diameter value of said work (W) after said first cutting is applied, a second diameter value of said work (W) after said second cutting is applied, and an X travel distance of said tool (41) in said X-axis direction from when said first cutting is finished until when said second cutting is finished, wherein said first and second diameter values are input from said input unit, and said first and second diameter values and said X travel distance are input into an equation used for computing the trigonometric relationship;
• applies, via said tool post drive unit, third cutting to said work (W), after said amount of deviation is corrected by transferring said tool post (40) via said tool post drive unit in said Y-axis direction.

A program recording medium for use with a computer for executing instructions stored to said medium to perform a method to control a lathe, comprising:

• controlling the lathe to grasp a work such that a center line of the work is in a Z-axis direction;
• controlling the lathe to machine said work by abutting a tool, which is attached to a tool post on said work;
• controlling the lathe to transfer said tool post in an X-axis direction, which is a direction extending from said tool (41) to said work (W) and is a direction different from said Z-axis direction, and in a Y-axis direction different from said X-axis direction and said Z-axis direction;
• controlling the lathe to drive a tool post drive unit, such that said tool is transferred in said X-axis direction and in said Y-axis direction;
• accepting, as an input, a value of a diameter of said work measured;
• controlling the lathe to apply, via said tool post drive unit, first cutting to said work (W) and subsequent second cutting to said work (W) while transferring said tool (41) in said X-axis direction;
• calculating, as an amount of deviation, a distance in said Y-axis direction 18 between an X-Z reference plane on which said center line of said work (W) exists and an abutting part of said tool (41) abutting on said work (W), based on a trigonometric relationship between a first diameter value of said work (W) after said first cutting is applied, a second diameter value of said work (W) after said second cutting is applied, and an X travel distance of said tool (41) in said X-axis direction from when said first cutting is finished until when said second cutting is finished;
• and
• controlling the lathe to apply, via said tool post drive unit, a third cutting to said work (W), after said amount of deviation is corrected by transferring said tool post (40) via said tool post drive unit in said Y-axis direction.

A machining method by a lathe which cuts a work (W) by a tool (41) such that a center line of said work is in a Z-axis direction, the method comprising

• a first cutting step of applying first cutting to said work (W) by abutting said tool (41) on said work (W) while transferring said tool (41) in an X-axis direction which is different from said Z-axis direction;
• a first measuring step of measuring a first diameter value, which represents a diameter of said work (W) after said first cutting step;
• a second cutting step of applying second cutting to said work (W) by abutting said tool (41) on said work (W) while transferring said tool (41) in said X-axis direction after said first cutting step;
• a second measuring step of measuring a second diameter value, which represents a diameter of said work (W) after said second cutting step;
• a deviation amount calculating step of calculating, as an amount of deviation, a distance in said Y-axis direction between a an X-Z reference plane on which said center line of said work (W) exists and an abutting part of said tool abutting on said work (W), based on a trigonometric relationship between a first diameter value of said work (W) after said first cutting is applied, a second diameter value of said work (W) after said second cutting is applied, and an X travel distance of said tool (41) in said X-axis direction from when said first cutting step is finished until when said second cutting step is finished, wherein said first and second diameter values are input from said input unit and said first and second diameter values and said X travel distance are substituted into an equation used for computing said trigonometric relationship thus computed;
• and
• a third cutting step of applying, via said tool post drive unit, third cutting to said work (W), after said amount of deviation is corrected by transferring said tool post (4) via said tool post drive unit in said Y-axis direction.