JPH06110523A - Freely curved surface work data preparing method - Google Patents

Abstract

PURPOSE:To make a product in the shape of a freely curved surface suitable for cutting work by preparing tool passage data for cutting a shaft-shaped object to be cut containing the freely curved surface with a simultaneous triaxial control NC machine tool from freely curved surface data. CONSTITUTION:A shaft-shaped object 14 to be cut containing the freely curved surface is fitted to a rotary shaft A, rotated and moved in an X axis direction, and the object 14 to be cut is cut by a tool BM to move in a Z axis direction. A semi-straight vector (n) vertical to the rotary shaft A is extended in a reference direction from a position moved just for a moving amount in the X axis direction on the rotary shaft A and rotated just for a rotating amount oppositely to the rotating direction of the rotary shaft A, a tool passage point is selected corresponding to the intersection of an offset curved surface vector SOFF (u, v) based on the semi-straight vector (n) and a freely curved surface vector S(u, v), the tool point passage is arranged according to a cutting method corresponding to the rotating amount of the rotary shaft A and the moving amount in the X axis direction, and the tool passage data are prepared.

Description

Detailed Description of the Invention

[0001]

[Table of Contents] The present invention will be described in the following order. Industrial Application Conventional Technology (FIGS. 13 to 14) Problem to be Solved by the Invention (FIGS. 13 to 14) Means for Solving the Problem (FIGS. 1 to 3) Operation (FIGS. 1 to 3) Example) (1) Overall configuration of CAD / CAM system (Fig. 1) (2) Free curved surface processing data creation method according to Example (Fig. 1)
(FIG. 12) (3) Other Examples Effect of the Invention

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a free-form surface processing data generation method, for example, CAD / CAM (computer aided d).
It is suitable when applied to a case where a product having a free-form surface shape is cut by using data representing the free-form surface generated in esign / computer aided manufacturing).

[0003]

2. Description of the Related Art For example, when designing the shape of an object having a free-form surface using a CAD method (geometric model).
deling), in general, a designer specifies a plurality of points (called nodes) in a three-dimensional space through which a curved surface should pass, and operates a boundary curve network connecting the specified nodes with a desired vector function. Creates a curved surface represented by a so-called wire frame. Thus, a large number of framework spaces surrounded by boundary curves can be formed (this processing is called framework processing).

The boundary curve network formed by such frame processing itself represents a rough shape which the designer intends to design, and a boundary vector surrounding each frame space is used to define a predetermined vector function. If the curved surface that can be expressed can be interpolated, the free curved surface (which cannot be defined by a quadratic function) designed by the designer can be generated as a whole. Here, the curved surface stretched in each frame space forms the basic elements that make up the entire curved surface,
This is called a patch.

By the way, in order to give the generated free-form surface as a whole a more natural outer shape, two frame spaces adjacent to each other across the shared boundary are patched so as to satisfy the condition of tangential plane continuity at the shared boundary. As described above, a free-form surface creation method has been proposed in which the control edge vector around the shared boundary is reset (Japanese Patent Application No. 60-277448).
issue). This free-form surface creation method, as shown in FIG.
A quadrilateral patch vector S (u,
v) 1 and the vector S (u, v) 2 are represented by a vector function vector S (u, v) consisting of a cubic Bezier equation.

The two patch vectors S (u, v) 1
And to connect the vector S (u, v) 2 to the smooth line, the node vector P (00), the vector P (30) 1, the vector P (33) 1, the vector P ( 03), the vector P (33) 2, and the vector P (30) 2, the tangential planes are continuous at the common boundary COM of the adjacent quadrilateral patch vectors S (u, v) 1 and S (u, v) 2. The control side vector a1, vector a2, vector c1, and vector c2 that satisfy the condition are set.

Further, according to these control side vectors, control point vector P (11) 1, vector P (12) 1, vector P
The principle is to reset (11) 2 and vector P (12) 2. If such a method is applied to other shared boundaries, the patch vector S (u, v) 1 and the vector S will eventually be obtained.
(u, v) 2 can be connected smoothly with adjacent patches according to the condition of tangential plane continuity.

Here, the vector function vector S (u, v) consisting of the cubic Bezier equation is

[Equation 1] Is expressed using parameters u and v in the u direction and v direction, and shift operators E and F, as shown in the following equation for the control point vector P (ij).

[Equation 2]

[Equation 3]

[Equation 4]

[Equation 5] Have a relationship.

Further, the tangent plane means a plane formed by tangent vectors in the u direction and the v direction at each point of the shared boundary. For example, for the shared boundary COM in FIG. 14, the patch vector S (u, v). When the tangent planes of 1 and the vector S (u, v) 2 are the same, the condition of continuous tangent planes holds. According to this method, it is possible to easily design an object shape that is difficult to design in the conventional design method, such that the curved surface shape changes smoothly as the designer intends.

[0010]

By the way, a die of a product having an outer shape of a free-form surface represented by the patch vector S (u, v) generated in this way is, for example, CAD / C.
When cutting using a 3-axis control NC machine tool as an AM system, first, the patch vector S that is the cutting target
The offset surface vector SOFF (u, v) is generated by moving the position data representing the surface of (u, v) by the offset vector, and this offset surface vector SOFF (u, v) and the tool shape formed by, for example, an end mill are generated. Based on this, there is a free curved surface machining data creation method adapted to create tool path data for controlling the movement of a tool (JP-A-1-83082).

According to this free curved surface processing data creation method, when cutting a product having an outer shape including a free curved surface, the work is fixed on the XY table which moves in the X axis and Y axis directions, and the Z axis is used. Cutting was performed by moving a tool moving in a direction from point to point in space. However, as a shaft-shaped product including a free-form surface, for example, a jewelry such as a ring, a boss of a machine, a cam having a free-form surface, or a die for cutting the product, an appropriate cutting method is not always required. Is unthinkable.

In practice, when a shaft-shaped product including such a free-form surface is machined by using a 3-axis control NC machine tool, the product is turned over after the machining of the upper half shape including the shaft. Although it is conceivable to cut the remaining half of the shape, the cutting process becomes complicated and the tool path data for processing the free-form surface requires two types of data, the upper half and the lower half.

Usually, in the case of cutting a shaft-shaped product or a die thereof as described above, the object to be cut is attached to the A-axis which is a rotating shaft and rotated at a predetermined rotation speed, and the product is parallel to the rotating shaft. Simultaneous three-axis control NC machining consisting of two parallel movement axes and one rotation axis that cuts while rotating a tool such as an end mill that can move in the Z axis direction orthogonal to the rotation axis while moving in the X axis direction. Machines are used. In such a case, if tool path data for cutting a product of an axial shape including a free curved surface and its die using a simultaneous 3-axis control NC machine tool can be created from the free curved surface data, CA
It is considered that the utility of the D / CAM system as a whole can be remarkably improved.

The present invention has been made in consideration of the above points. Simultaneous three-axis control of a shaft-shaped workpiece including a free-form surface N
An object of the present invention is to propose a free curved surface machining data creation method capable of creating tool path data for cutting with a C machine tool from free curved surface data.

[0015]

In order to solve the above problems, according to the present invention, a shaft-shaped workpiece 14 including a free-form surface is attached to a rotary shaft A and rotated at a predetermined rotational speed, and at least the rotary shaft is rotated. A tool BM that moves in the X-axis direction parallel to A and moves in the Z-axis direction orthogonal to the rotation axis A
In the free-form surface processing data creation method SPO that creates tool path data DTCL for rotating the workpiece 14 by rotating the workpiece 14, the amount of rotation of the rotation axis A and the amount of movement in the X axis direction are obtained, and X on the rotation axis A is obtained. From the position moved by the amount of movement in the axial direction, a half-line vector n perpendicular to the rotation axis A is extended in the reference direction, and the half-line vector n is rotated by a rotation amount in the direction opposite to the rotation direction of the rotation axis A. A tool path point is selected according to the intersection of the straight-line vector n and the offset curved surface vector SOFF (u, v) based on the free-form surface vector S (u, v) of the object to be cut 14, and the tool path point is set on the rotary axis A. The tool path data DTCL is created by arranging according to the cutting method according to the rotation amount and the movement amount in the X-axis direction.

Further, in the present invention, when a tool path point is selected according to the intersection point vector X of the half straight line and the offset curved surface vector SOFF (u, v), if there are a plurality of intersection point vectors X, the half straight line vector n Among the plurality of intersection vector X of, the intersection having the longest distance from the rotation axis A is selected as the tool path point.

Further, in the present invention, when the tool path points are arranged by arranging the tool path points by arranging the tool path points by moving the X-axis direction moving quantity in proportion to the moving quantity of the rotary axis A, the tool path points are continuously arranged. Rearrangement is performed so that tool path data DTCL that is continuous on the spiral is created.

Further, according to the present invention, when the tool path data DTCL is created by arranging the tool path points by changing the amount of movement in the X axis direction for each rotation of the rotation axis A, a plurality of rings are predetermined in the X axis direction. Tool path data DTCL arranged at intervals is created.

Furthermore, in the present invention, when the tool path data DTCL is created by arranging the tool path points by converting the amount of movement in the X-axis direction for each predetermined angle rotation of the rotary axis, the tool path data that changes stepwise. Created DTCL.

[0020]

The rotation amount of the rotation axis A and the movement amount in the X-axis direction are obtained, and from the position moved by the movement amount in the X-axis direction on the rotation axis A, the half-line vector n perpendicular to the rotation axis A is set as the reference direction. The half-line vector n is extended and rotated by an amount of rotation in the direction opposite to the rotation direction of the rotation axis A, and the offset curved-surface vector SOFF (based on the half-line vector n and the free-form surface vector S (u, v) of the workpiece 14 is turned off. Select a tool path point according to the intersection vector X of (u, v), and arrange the tool path points according to the cutting method according to the rotation amount of the rotation axis and the movement amount in the X-axis direction to create the tool path data DTCL. By doing so,
Axial workpiece 14 including free-form surface vector S (u, v)
Tool path data DTCL for simultaneous machining with the three-axis control NC machine tool 10 to the free-form surface data vector S (u,
v) can be created from.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

(1) Overall Structure of CAD / CAM System In FIG. 1, reference numeral 1 denotes a CAD / CAM system as a whole, a free-form surface forming device 2 and a free-form surface cutting tool each including a central processing unit (CPU). It is composed of an NC milling machine (machining center) 4 including a route creation device 3 and a simultaneous three-axis control NC machine tool 4. Using the CAD method described above in the free-form surface creation device 2, after creating shape data DTS consisting of the free-form surface patch vector S (u, v) representing the external shape of the axial product including the free-form surface, this is created. It is sent to the tool path creation device 3.

The tool path creating device 3 creates an offset curved surface vector SOFF (u, v) when, for example, a ball end mill is used as a tool based on the inputted shape data DTS, and as shown in FIG. Simultaneous 3-axis control NC machine tool 4 according to the tool path data creation processing procedure SP0
Create tool path data DTCL for cutting using. The simultaneous three-axis control NC machine tool 4 is controlled on the basis of the tool path data DTCL input via the flottu disk 5, whereby it is possible to perform cutting of a product having an axial shape including a free curved surface. ing.

The tool path creating device 3 has a display, a keyboard, a mouse, etc. as the display device 6 and the input device 7, and the designer can operate the input device 7 while observing the menu screen displayed on the display device 6. For example, CPU
Executes the tool path data creation processing procedure SP0 shown in FIG. 2 and creates tool path data DTCL for cutting using the simultaneous three-axis control NC machine tool 4 according to an instruction from the designer. .

Further, the simultaneous three-axis control NC machine tool is, as shown in FIG. 3, mounted on a spindle spindle 11 which moves in the Z-axis direction and a chuck 12 thereof, and a ball end mill BM which rotates at a predetermined rotational speed, and an A-axis. Rotary table 1
The workpiece 14 which is attached to 3 and rotates at a rotational speed of 10 to 20 rotations / minute, and the A-axis rotary table 13 placed on the A-axis rotary table 13 and the workpiece 14.
The X-axis table 15 is configured to move in the X-axis direction parallel to the A-axis.

As a result, the A-axis of the workpiece 14 and X
The ball end mill BM is moved to Z in synchronization with the axial movement.
By controlling the movement in the axial direction, cutting of a product having an axial shape including a free curved surface is executed.

(2) Free Curved Surface Machining Data Creation Method According to Embodiment Here, the CPU of the tool path creation device 3 of this embodiment is instructed by the designer to create a tool path data creation processing procedure SP0.
At the next step SP1, the offset point group is generated in a grid pattern based on the shape data DTS consisting of the free-form surface patch vector S (u, v), and the bi-linear Bezier equation is generated in this grid point. Interpolate with a free-form surface using.

That is, first, a conventional free-form surface S (u,
For v), ball end mill BM used for cutting
The offset point cloud offset by the radius r and the cutting allowance is calculated. As shown in FIG. 4, the offset point is a point extended from the point on the free-form surface vector S (u, v) by a certain amount in the normal direction. However, the offset point from the boundary of the free-form surface vector S (u, v) has an arc shape and is generated spherically in three dimensions.

In this way, the free-form surface vector S (u, v)
When an infinite number of offset points are generated with respect to, and the envelope surface is taken, the offset surface vector SOF as shown in FIG.
F (u, v) can be done. This offset surface vector SOFF (u,
In v), which point on the curved surface the ball end mill BM
Even if the center of the ball, that is, the center of the tip sphere of the ball end mill BM exists, the free-form surface vector S as the object to be cut
This means that (u, v) cannot be cut too much.

In reality, it is impossible to generate an infinite number of offset points, and a finite number of offset points are generated in a grid pattern in consideration of the allowable range of over-cutting or uncutting. In the case of this embodiment, as shown in FIG. 6, the offset points thus generated in a grid pattern are given by

[Equation 6] The offset curved surface vector SOFF (u, v) is generated by interpolating the free curved surface patch vector S (u, v), which is a bilinear Bezier equation. For example, as in FIG. 5, one free-form surface patch vector S (u, v)
On the other hand, when an offset surface is generated with a bilinear Bezier surface, the offset surface vector SOFF as shown in FIG.
(u, v) is generated.

Here, what is necessary as the tool path data DTCL of the simultaneous three-axis control NC machine tool 10 is, as described above with reference to FIG. 3, coordinate values in the X and Z directions indicating the position of the ball end mill BM as a tool. And the rotation angle of the A-axis, which is the rotation amount of the workpiece 14. By determining these three data, one cutting point is determined. Therefore, by continuously obtaining these cutting points, it is possible to obtain the tool path data DTCL for cutting a desired free-form surface shape. However, the ball end mill BM is arranged immediately above the A axis that is the rotation axis, that is, at the position of y = 0.

The coordinate values in the X and Z directions and the rotation angle of the A axis are in a dependent relationship, and if two of them are determined, the other one is automatically determined. Therefore, in the case of this tool path data creation processing procedure SP0, the CPU first proceeds to step SP2.
At step S3, the rotation amount of the rotation axis, that is, the A-axis is obtained, and at the next step SP3, the movement amount in the X-axis direction is obtained in proportion to the rotation amount of the rotation axis.

Subsequently, in the next step SP4 and step SP5, the CPU extends the half line perpendicular to the rotation axis in the reference direction from the position moved by the movement amount in the X axis direction on the rotation axis, as shown in FIG. As shown, when the center X coordinate of the ball end mill is XO and the free-form surface vector S (u, v) consisting of the workpiece rotates by AO, a straight line passing through XO and parallel to the Z-axis and the offset surface vector SOFF The intersection of (u, v) becomes the tool path candidate point. That is, the point vector X is a tool path candidate point, and the Z coordinate value at that time is ZO. Therefore, the data of the tool path candidate points at this time becomes (XO, ZO, AO).

In the actual calculation, instead of rotating the free-form surface vector S (u, v) formed by the workpiece 14, the half line is rotated in the opposite direction to the rotation direction of the free-form surface vector S (u, v). . That is, as shown in FIG. 9, a vector X is defined as an intersection of a half-line which is rotated through the point vector Q on the X axis and is inversely rotated by AO and the offset curved surface vector SOFF (u, v). In the tool path candidate point data at this time, the X coordinate is the X coordinate of the point vector Q (= the X coordinate of the point X), and the Z coordinate is the vector QX,
The rotation angle is AO.

With respect to this tool path candidate point data, assuming that the direction vector of the half line when the rotation axis is reversely rotated by AO is vector n, the following equation of the straight line at that time is:

[Equation 7] Becomes However, t is a parameter and t> 0. Therefore, equations (6) and (7) are equal, that is,

[Equation 8] By solving this, the parameters u, v,
Find t. However, the parameters u, v, and t are

[Equation 9] All the solutions are obtained from the offset surface vector SOFF (u, v).

In this way, some intersection vectors X may be obtained for a certain rotation angle AO and a certain point vector Q, but all of them become tool path candidate points. The free-form surface vector S (u,
When v) has a shape as shown in FIG. 10, the intersection vector X is 3 with respect to a certain rotation angle A and a certain point vector Q.
I want it. At this time, the vector X0, the vector X1, and the vector X2 are the tool path candidate points, but in order to prevent overcutting, the tool path point is the intersection vector X2 farther from the center (rotation axis), and this is the tool path point.

Accordingly, in step SP6, the CPU
A point farthest from the rotation axis A is selected in the intersection point vector X on the half-line vector n, and in the next step SP7, the distance from the rotation axis A to the tool path point is obtained, and this distance is Z at the position at this moment. It becomes a coordinate value. In this way, the tool path point has three values (A, X, Z), and a plurality of Z are obtained for the rotation angle A of a certain rotation axis and the movement amount X in the X direction, and the maximum Z is the tool. Use as a path.

Subsequently, in the next step SP8, the CPU determines whether or not the tool path points sufficient for cutting all the workpiece 14 have been calculated. If a negative result is obtained here, the CPU returns to the step SP2. If a positive result is obtained, the process proceeds to the next step SP9.

Actually, the tool path points are calculated by the method of step SP2 to step SP8, but the finally necessary data are those arranged in the order of machining, and in the case of this simultaneous three-axis control NC machine tool 10. In the next step SP9, since the processing is performed in a spiral shape, the CPU generates spiral tool path data DTCL.

That is, the movement range in the X direction is first set so that the object to be cut can be machined without excess or deficiency. Next, each time the workpiece 14 makes one revolution, the amount XS of movement of the ball end mill BM in the X-axis direction is determined, and the amount of revolution .theta.S at which the ball end mill BM is rotated one revolution is determined. That is, the rotation axis is θ
Every s rotation, the following formula

[Equation 10] The ball end mill BM moves in the X direction, and the Z value corresponding to the rotation angle θ S and the X value at each moment is calculated.
When the tool path data DTCL is created in this way, the object to be cut is processed into a spiral shape.

When tool path data DTCL for machining a boss-shaped product including the free-form surface vector S (u, v) as shown in FIG. 11 is created in accordance with the above procedure, the spiral as shown in FIG. The data is such that tool path points are arranged in a line.

According to the above method, the rotation amount of the rotation axis A and the movement amount in the X-axis direction are obtained, and from the position moved on the rotation axis A by the movement amount in the X-axis direction, the half axis perpendicular to the rotation axis A is obtained. The straight line is extended in the reference direction, and the half line is rotated by the amount of rotation in the direction opposite to the rotation direction of the rotation axis, and the offset curved surface vector SOFF (based on the free curved surface vector S (u, v) of the half line and the workpiece 14 is set. Select a tool path point according to the intersection vector X of (u, v), and arrange the tool path points according to the cutting method according to the rotation amount of the rotation axis and the movement amount in the X-axis direction to create the tool path data DTCL. By doing so, the tool path data DTCL for cutting the shaft-shaped workpiece 14 including the free-form surface vector S (u, v) by the simultaneous 3-axis control NC machine tool 10 is converted into the free-form surface data vector. Free-form surface processing data that can be easily created from S (u, v) It can realize the data creation method.

(3) Other Embodiments In the above-described embodiment, the tool path points are arranged by determining the amount of rotation of the rotary shaft and the amount of movement in the X-axis direction proportional to this amount of rotation, and the spiral tool path is arranged. Although the data is created, instead of this, the ring is moved in the X-axis direction each time the rotary shaft rotates, or the ring is arranged in the X-axis direction by moving the rotary shaft in each X-axis direction. Step-shaped tool path data may be created.

In the above embodiment, the invention is
The present invention was applied to a simultaneous three-axis control NC machine tool that controls a parallel movement axis and one rotation axis, but if at least two parallel movement axes and one rotation axis cannot be controlled, more axes can be controlled.
It can be widely applied to C machine tools.

Further, in the above-mentioned embodiment, the case where the ball end mill is used as the tool of the simultaneous three-axis control NC machine tool according to the present invention has been described, but the tool according to the present invention is not limited to this, and the radius end mill or the Even if another tool such as a flat end mill is used, the same effect as that of the above-described embodiment can be realized.

Further, in the above-mentioned embodiment, the case where the free curved surface of the object to be cut and the offset curved surface thereof are expressed by using the bilinear Bezier equation has been described.
Even if it is expressed by using the following Bezier expression or another vector expression representing a spline function, the same effect as that of the above-described embodiment can be realized.

[0047]

As described above, according to the present invention, the amount of rotation of the rotary shaft and the amount of movement in the X-axis direction are obtained, and the position perpendicular to the rotary shaft is moved from the position moved by the amount of movement in the X-axis direction on the rotary shaft. A straight half-line in the reference direction, and rotate that half-line in the direction opposite to the rotation direction of the rotation axis by the amount of rotation, and set the tool path point according to the intersection of the half-line and the offset curved surface based on the free-form surface of the workpiece. Select and set the tool path point to the rotation amount of the rotary axis and X
By creating tool path data by arranging according to the cutting method according to the amount of movement in the axial direction, it is possible to cut a shaft-shaped workpiece including a free-form surface with the simultaneous 3-axis control NC machine tool. It is possible to realize a free curved surface machining data creation method capable of creating tool path data from free curved surface data.

[Brief description of drawings]

FIG. 1 is a block diagram showing the overall configuration of a CAD / CAM system that executes a free-form surface processing data creation method according to the present invention.

FIG. 2 is a flow chart for explaining a tool path data generation processing procedure as a free-form surface processing data generation method according to the present invention.

FIG. 3 is a schematic perspective view for explaining a simultaneous three-axis control NC machine tool controlled by tool path data created in a tool path data generation processing procedure.

FIG. 4 is a schematic diagram for explaining offset points with respect to a free-form surface.

FIG. 5 is a schematic diagram for explaining an offset surface obtained as a set of offset points.

FIG. 6 is a schematic diagram for explaining free-form surface data that is a bilinear Bezier surface.

FIG. 7 is a schematic diagram for explaining offset curved surface data composed of bilinear Bezier curved surfaces.

FIG. 8 is a schematic diagram for explaining an offset curved surface of the embodiment.

FIG. 9: Step SP4 of the tool path data generation processing procedure
FIG. 6 is a schematic diagram used to explain Step SP5.

FIG. 10: Step SP of tool path data generation processing procedure
6 is a schematic diagram for explaining 6 and step SP7.

FIG. 11 is a schematic diagram showing a shaft-shaped product including free-form surface data.

12 is a schematic diagram showing tool path data generated for the free-form surface data of FIG.

FIG. 13 is a schematic diagram used for explaining a control side vector of two patches as a free-form surface.

FIG. 14 is a schematic diagram used for explaining a condition of continuous tangent plane as a free-form surface.

[Explanation of symbols]

1 ... CAD / CAM system, 2 ... Free curved surface creation device, 3 ... Free curved surface cutting tool path creation device, 4, 10
...... Simultaneous 3-axis control NC machine tool, 5 ... Flotpi disk, 6 ... Display device, 7 ... Input device, 11 ... Spindle spindle, 12 ... Chuck, 13 ... A-axis rotary table, 14 ... Cover Cutting, 15 ... X-axis table, B
M: Ball end mill.

Claims (5)

[Claims] 1. A Z-axis that is orthogonal to the above-mentioned rotary shaft is provided by mounting a shaft-shaped workpiece including a free-form surface on a rotary shaft and rotating it at a predetermined number of rotations, and at least moving it in the X-axis direction parallel to the rotary shaft. In a free-form surface processing data creating method for creating tool path data for cutting the work by rotating a tool that moves in the axial direction, the amount of rotation of the rotary shaft and the amount of movement in the X-axis direction are obtained,
A half line perpendicular to the rotation axis is extended in the reference direction from a position on the rotation axis moved by the movement amount in the X axis direction, and the half line is rotated in the opposite direction to the rotation direction of the rotation axis by the rotation amount. The tool path point is selected according to the intersection of the half-line and the offset curved surface based on the free-form surface of the workpiece, and the tool path point is set in the rotation amount of the rotary shaft and in the X-axis direction. A free-form surface machining data creating method, characterized in that the tool path data is created by arranging the tool path data according to a cutting method according to a movement amount. 2. When selecting a tool path point according to the intersection of the half line and the offset curved surface, and when there are a plurality of intersections, among the plurality of intersections on the half line, from the rotation axis. The free curved surface machining data creation method according to claim 1, wherein the intersection point having the longest distance is selected as the tool path point. 3. The tool path point is continuously moved when the tool path data is created by arranging the tool path points by moving the moving quantity in the X-axis direction in proportion to the moving quantity of the rotary shaft. The free-form surface processing data creating method according to claim 1, wherein the tool path data is arranged so as to be rearranged and continuous on a spiral. 4. A plurality of rings are predetermined in the X-axis direction when the tool-path data is created by arranging the tool-path points by changing the movement amount in the X-axis direction for each rotation of the rotary shaft. The free curved surface processing data creating method according to claim 1, wherein the tool path data arranged at intervals is created. 5. The tool path data that changes stepwise when the tool path data is created by arranging the tool path points by converting the amount of movement in the X-axis direction for each predetermined angular rotation of the rotary shaft. The free-form surface processing data creating method according to claim 1, wherein