JP2002263903A - Method and tool for turning - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for turning capable of remarkably increasing the surface roughess accuracy of a cut-finished surface. SOLUTION: A tool 10 is disposed aslant a specified angle βrelative to a work axis Q so that the linear cutting edge 10a of the tool 10 is twisted relative to the work axis Q. With the tool 10 held in the state that a feed for cutting by an amount of a desired depth of cut m given to the tool in an X direction, a feed F is given to the tool 10 in the tangential direction to the outer peripheral surface of the work. Where a cut point crossed with the linear cutting edge 10 on the outer peripheral surface of the work W is m, the cut point m is moved continuously also in the work axial direction Q for feed F to cut the outside diameter of the work W so as to form a cut-finished surface with high surface roughness accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turning method and a turning tool for the purpose of improving the precision of a finished surface after cutting.

[0002]

2. Description of the Related Art FIG. 12 shows an example of round bar outer peripheral cutting as a typical form of cylindrical cutting by a lathe. This means that after the tool (bite) 100 is moved from the outer peripheral side of the work 101 in the axial direction thereof and cut by a predetermined cutting depth a, the tool 100 is fed to the tool 100 as a feed F1 in the axial direction of the work 101. The cutting is performed by giving a constant feed amount P for each rotation.

FIG. 13 shows an example of groove cutting. This is because the tool 102, such as a parting tool,
(A similar technique is disclosed, for example, in Japanese Patent Application Laid-Open Nos. 2000-61702 and 200).
0-84780).

[0004]

In the example shown in FIG. 12, the tool 101 is moved in the direction of the axis of the work by a constant feed amount P for each rotation of the work.
A machining mark 104 called a tool mark in which the cutting edge shape of the tool 101 is spirally transferred is formed on the first cut surface. The surface roughness of the cut surface in the direction of the workpiece axis is determined by the size of the peak of the tool mark 104 and the tool 10.
It is almost determined by the surface roughness of one cutting edge. Since the surface roughness of the cutting edge is smaller than the size of the ridge of the tool mark 104, it is conventional to reduce the feed amount P of the tool 101 per one rotation of the work to reduce the surface roughness of the cut surface. This is a general method. However, when the feed amount P of the tool 101 per rotation of the work is reduced, there is a problem that the cut amount per unit time, that is, the machining efficiency is reduced.

In the example shown in FIG. 13, the tool 102 is cut in the radial direction of the work 103. Therefore, the above-described tool mark 104 is not generated on the finished surface and the uneven shape of the cutting edge is obtained. It is only transferred, so its surface roughness is reduced. However, since it is necessary to perform cutting using the tool 102 having the same width as the groove width to be machined, especially when the groove width is large, the length of the cut portion increases accordingly, and the cutting resistance increases. As a result, a so-called chatter phenomenon occurs and the surface roughness deteriorates, and there is a problem that cutting cannot be performed depending on a groove width dimension.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a turning method and a turning tool with improved surface roughness accuracy of a cut surface.

[0007]

According to a first aspect of the present invention, there is provided a turning method for cylindrically cutting an outer periphery of a work, wherein a tool having a linear cutting edge is used as the cutting edge (more specifically, the cutting edge). The edge or edge of the blade) is tilted and arranged so that it has a torsional relationship with the workpiece axis.
After the tool is moved in the axial direction of the work from the outer peripheral side of the work so as to obtain a desired cutting amount, the cutting is performed by giving the tool a feed in the tangential direction of the finished surface of the work.

Therefore, according to the first aspect of the present invention, when the tool is fed in the tangential direction of the workpiece, the cutting point, which is the contact point between the inclined cutting edge and the workpiece, moves continuously in the axial direction of the workpiece. Thus, since the cutting is performed in a so-called continuous cutting mode, a tool mark that reduces the surface roughness of the cut surface is not generated.

According to a second aspect of the present invention, on the premise of the turning method of the first aspect, prior to cutting, the surface roughness of the flank adjacent to the tool cutting edge is determined in advance. Measure, based on the height from the valley bottom to the peak of the roughness curve and the interval between the peaks and the processing diameter of the work,
Calculate the ratio of the tangential movement speed and the work axis direction movement speed required to trace the passing locus of the valley bottom equivalent part of the roughness curve at the time of tool feed application by the ridge top equivalent part near the valley bottom. The tool is characterized in that the inclination angle of the tool is set so as to become the ratio of the calculated moving speed.

In this case, since it is assumed that the surface roughness of the flank adjacent to the actual cutting edge (main cutting edge) is transferred to the cut and finished surface on the work side, it is calculated from the above moving speed ratio. The inclination angle of the tool to be formed is such that the concave portion of the flank adjacent to the cutting edge, that is, the convex portion formed on the work side by transferring the portion corresponding to the valley portion of the roughness curve is also adjacent to the cutting edge. In order to scrape off the convex portion near the concave portion of the flank, the passage locus of the valley bottom equivalent portion of the roughness curve at the time of feeding of the tool is set as an angle such that the peak equivalent portion near the valley bottom can be traced. Ask.

Therefore, according to the second aspect of the present invention, as described above, the convex portion formed on the work side by the transfer of the concave portion of the tool flank is scraped off by the convex portion adjacent to the concave portion of the tool flank. Due to this, the actual cut surface does not reflect the surface roughness of the flank adjacent to the tool cutting edge, that is, the uneven shape is transferred as it is, and the surface roughness of the cut surface is inevitably reduced to the tool side relief. The surface roughness can be made smaller than the surface roughness.

According to a third aspect of the present invention, there is provided a turning tool for cutting a concave arc-shaped surface on the outer periphery of a workpiece by giving a rotary feed to the tool itself, wherein the spherical body has a curvature corresponding to the concave arc-shaped surface. In addition to setting a single tool rotation center line with a straight line passing through its center, a continuous cutting edge is formed along the spherical surface, and this cutting edge is twisted with respect to each of the work axis and the tool rotation center line. It is characterized by being inclined so as to satisfy the following relationship.

The invention according to a fourth aspect is based on the premise that the turning method using the tool according to the third aspect is performed, and the axis of the workpiece to be machined and the tool rotation center line are parallel. The state is characterized in that the cutting is performed by giving a feed by rotating the tool around the tool rotation center line.

Therefore, according to the third and fourth aspects of the present invention, when the concave curved surface is cut, the cutting is performed in a so-called continuous cutting mode in the same manner as the first aspect of the present invention. No tool mark for lowering the surface roughness is generated.

A fifth aspect of the present invention is based on the premise that the turning method using the tool according to the third aspect of the present invention is performed, and prior to cutting, a flank surface adjacent to a tool cutting edge is preliminarily provided. The surface roughness of the roughness curve is measured, and based on the height from the bottom to the top of the roughness curve, the distance between the tops and the diameter of the tool spherical portion including the cutting edge, the bottom of the roughness curve at the time of tool rotation. The inclination angle of the tool rotation center line with respect to the axis of the work required for tracing the passing locus of the corresponding part by the above-mentioned peak top near the valley bottom is calculated, and the angle of the tool rotation center line with respect to the axis of the work is calculated as described above. The tool is characterized in that the tool is tilted so as to have a predetermined tilt angle, and in that state, the tool is rotated around the tool rotation center line to give a feed to perform cutting.

Therefore, according to the fifth aspect of the present invention, since the inclination angle of the tool rotation center line is obtained based on the same principle as the second aspect of the present invention, the actual cut surface is a tool. The surface roughness of the flank adjacent to the cutting edge on the side, that is, the uneven shape is not directly transferred,
Inevitably, the surface roughness of the finished surface can be made smaller than the surface roughness of the flank on the tool side.

[0017]

According to the first aspect of the present invention, a tool having a straight cutting edge is provided to be inclined with respect to the direction of the workpiece axis, and the tool is fed in the tangential direction of the workpiece cutting surface. Since the cutting is performed, the surface roughness can be reduced without generating a tool mark by forming a continuous cutting form with a continuous cutting edge, and as a result, the surface roughness accuracy of the cut surface is greatly improved. In addition, even when the processing length is long, the cutting width at the actual cutting point is small, so that the occurrence of chatter can be prevented beforehand, and the cutting edges involved in cutting move sequentially, Accordingly, there is an advantage that the cutting heat generated in the cutting edge is efficiently radiated and the tool life is extended.

According to the second aspect of the present invention, the surface roughness of the flank of the tool is measured in advance, and the locus of the portion corresponding to the valley bottom of the roughness curve when the tool is fed is given to the peak of the valley near the valley bottom. Calculate the ratio between the tangential movement speed and the work axis direction movement speed required for the corresponding part to trace, and set the tool inclination angle to be the calculated movement speed ratio for cutting. Therefore, in addition to the same effect as the invention described in claim 1, it is possible to reduce the surface roughness of the finished surface of the workpiece until the surface roughness becomes equal to or less than the surface roughness of the tool flank. This has the advantage that the surface roughness of the finished surface can be further increased.

According to the third and fourth aspects of the present invention, the cutting method is performed using a tool having a continuous cutting edge corresponding to the concave arc-shaped surface on the workpiece side. Similarly, it is possible to reduce the surface roughness without generating a tool mark, and to prevent backlash which occurs during quadrant movement in, for example, simultaneous two-axis machining by conventional NC control, and a decrease in machining accuracy associated therewith.

According to the invention set forth in claim 5, according to claim 3,
Based on the same principle as the invention described in claim 2, the surface roughness of the flank adjacent to the tool cutting edge is measured in advance, and the root of the roughness curve corresponds to the roughness curve when the tool rotates. The inclination angle of the tool rotation center line with respect to the workpiece axis required for tracing the passing locus of the part by the above-mentioned peak top near the valley bottom was calculated, and the angle of the tool rotation center line with respect to the workpiece axis was calculated as described above. Since the tool is tilted so as to have an inclination angle, and the tool is rotated about the tool rotation center line in this state to feed and perform cutting, the same as the invention according to claim 3 is performed. In addition to the effect, there is an advantage that the surface roughness of the cut finished surface of the work can be reduced to be equal to or less than the surface roughness of the tool flank, and the surface roughness of the cut finished surface can be further increased.

[0021]

1 to 5 show a preferred embodiment of the present invention. FIG. 1 is a front view of a machine tool used for turning according to the present invention, and FIG. 2 is a plan view of the same. FIG. 3 is an enlarged view of a main part of FIGS. This embodiment corresponds to the first aspect of the present invention.

As shown in FIGS. 1 and 2, the machine tool is roughly divided into a bed 1 and a head stock 2 and a vertical head 3 provided on the bed 1. As is well known, the head stock 2 is provided with a motor 4 (FIG. 3).
A chuck 6 for gripping, for example, a round bar-shaped workpiece W is provided at the tip of the main shaft 5 that is driven to rotate by the rotation of the main shaft 5.
The vertical unit 3 supports a tool spindle 9 in a vertical posture on a column 8 driven in a horizontal direction (Y direction, tangential direction) on the bed 1 by a feeder 7 (see FIG. 3) mainly composed of a motor (not shown). The tool spindle 9 is provided with a tool 10 having a straight cutting edge 10a at its tip, and the inclination angle of the cutting edge 10a of the tool 10 with respect to the workpiece axis Q is arbitrarily changed. The rotation is indexed by the motor 11 so that the rotation can be performed.

The motor 11 is provided with a rotary encoder 12 as a position detector. The motor 4 for driving the rotation of the workpiece and the feeder 7 of the vertical unit 3 are controlled by a controller 13 as shown in FIG.

FIG. 3A is an enlarged plan view of a main part of FIG. 1, and FIG. 3B is a view of FIG. 3A viewed from the Y direction. As shown in the figure, the work W is held by the chuck 6 and is driven to rotate together with the chuck 6 in the direction of arrow c. The tool 10 has a straight cutting edge 10 here.
The work axis is illustrated as a simple rectangular one having a, and the straight cutting edge 10a, that is, the edge of the cutting edge 10a or the edge thereof has a so-called torsional relationship with the work axis Q. It is arranged at an angle β to Q.

Then, after holding the tool 10 in a state in which the desired amount of cutting has been applied in the X direction,
A feed in the Y direction, that is, a feed F in the tangential direction of the outer peripheral surface of the work is applied to the tool 10. Here, assuming that a point at which the linear cutting edge 10a intersects on the outer peripheral surface of the work W is a cutting point m, the cutting point m is shifted in the work axis direction Q due to the feed F described above.
And the outer diameter of the work W is cut to form the cut finish surface S.

As described above, the tool 10 having the straight cutting edge 10a is arranged at an angle β so as to be twisted with respect to the workpiece axis Q, and the tool 10 is placed in the tangential direction of the outer peripheral surface of the workpiece. By adopting the method of moving and cutting, it becomes a form like continuous cutting by a single-point tool while being a straight cutting edge 10a,
There is no tool mark as in the conventional example, and the surface roughness of the cut surface S can be reduced. Further, even when the cutting width is large, it is possible to perform the machining smoothly without generating the chatter phenomenon. In addition, since the cutting edge 10a directly involved in the cutting moves sequentially, the cutting heat generated on the cutting edge 10a due to the cutting is efficiently radiated, so that the tool life is extended.

Here, prior to the cutting in the above procedure, the surface roughness of the flank adjacent to the cutting edge 10a of the tool 10 is measured in advance, and the surface roughness of the tool is determined according to the degree of the surface roughness. The inclination angle β of 10 is set.

More specifically, as shown in FIG. 4, the surface roughness of the flank adjacent to the cutting edge 10a of the tool 10 is measured and recorded by using a known roughness measuring machine, and the surface roughness is measured and recorded. And print out (steps S1 and S2). FIG. 5 shows an example of a roughness curve obtained by measuring the surface roughness of the flank. Then, for the roughness curve of FIG. 5, the height H from the bottom of the valley to the peak and the interval L between the peaks are obtained.
As a method of obtaining, for example, combinations of valley bottoms and peaks up to the third in descending order of height are selected, and their heights H1,
After obtaining H2, H3 and intervals L1, L2, L3 between the peaks, H = (H1 + H2 +
H3) / 3 and L = (L1 + L2 + L3) / 3 are obtained (step S3).

Next, the processing dimensions of the cut surface S are read from the instruction drawing of the work W to be processed, and the H dimensions and L dimensions are read.
Based on the dimensions and the radius r of the processing diameter of the workpiece W, the moving speed Vy of the tool 10 in the tangential direction of the cut surface S, ie, the Y direction, and the workpiece axial direction Q, ie, the Z direction, as in step S5 of FIG. The ratio Vy: Vz to the moving speed Vz of the tool 10 is obtained as Vy: Vz = B: L. Here, B is obtained by the following equation (1). Then, the inclination angle β of the tool 10 with respect to the work axis Q is set such that the relationship of Vy: Vz = B: L is satisfied (step S6).

[0030]

(Equation 1)

The above calculation formula is based on the premise that the surface roughness of the tool flank adjacent to the tool cutting edge 10a which controls the actual cutting is transferred to the cut surface S on the work side.
The convex portion on the cut surface S side of the work due to the transfer of the concave portion of the flank adjacent to the tool cutting edge 10a is also cut by the convex portion adjacent to the concave portion of the flank, that is, the tool 10 The ratio Vy of the moving speed Vy in the tangential direction and the moving speed Vz in the workpiece axis direction Q such that the trajectory of the valley bottom corresponding to the roughness curve traces the passing locus at the top of the valley bottom at the time of feeding. The value of B is calculated such that Vz becomes the same as B: L, and the inclination angle β of the tool 10 with respect to the workpiece axis Q is set accordingly.

Accordingly, when the actual machining is performed in the form shown in FIG. 3, the surface roughness of the cut surface S of the work W can be surely made smaller than the surface roughness of the flank of the tool. The surface roughness accuracy will be greatly improved. This procedure corresponds to the invention described in claim 2.

FIGS. 6 and 7 show a second embodiment of the present invention. FIG. 6 is a front view of the entire machine tool, and FIG. 7 is an enlarged view of a main part of FIG. FIG. 6A is an enlarged plan view of a main part of FIG. 6, and FIG. 6B is a view of FIG. 6A viewed from the Y direction. This embodiment is described in claims 3 and 4.
Corresponds to the invention described in (1).

As shown in FIG. 6, the basic configuration of the machine tool is the same as that shown in FIG. 1, except that only the tool at the tip of the tool spindle 9 is changed. That is, a rotary unit 20 having a substantially spherical shape and a motor 13 for rotating the tool 20 around a tool rotation center line R described later are supported by a holder 14 to form a tool unit 15. It is detachably attached to the tip of the main shaft 9. The rotation angle position of the tool spindle 9 is adjusted so that the workpiece axis Q and the tool rotation center line R are parallel to each other.
1 (see FIG. 1).

As shown in FIG. 7, a workpiece having a concave arc-shaped surface K, that is, a substantially drum-shaped workpiece W1 is gripped by a chuck 6 of a machine tool similar to that shown in FIG.
Is driven to rotate. The tool 20 is formed mainly of a spherical body 16 having a curvature corresponding to the concave arc-shaped surface K on the work W1 side, and has a shaft portion 17 as a tool rotation center line R parallel to the work axis Q. Are formed, and the cutting edge 20a is formed to be continuous along the spherical surface of the spherical body 16 and to be inclined so as to be twisted with respect to both the workpiece axis Q and the tool rotation center line R. ing.

The tool 20 having such a cutting edge 20a
Are arranged so as to be parallel to the workpiece axis Q and to have a desired cutting amount. In this state, tool 2
By rotating the shaft 0 as a rotation center line R, the concave arc-shaped surface K of the work W is continuously cut as a cut finish surface. This makes it possible to reduce the surface roughness of the cut finished surface K having a concave arc shape as in the case of FIG. 1 without generating a tool mark. In particular, it is possible to prevent a decrease in machining accuracy due to backlash generated during quadrant movement, as compared with a case where machining is performed by simultaneous X-Z two-axis control of NC control as in the related art.

8 to 11 show a third embodiment of the present invention. FIG. 8 is a front view of the entire machine tool, FIG. 9 is an enlarged view of a main part of FIG. 8, and in particular, FIG. 8A is an enlarged plan view of a main part of FIG. 8, and FIG. 8B is a plan view of FIG.
Seen from the direction. This embodiment corresponds to the invention described in claim 5.

As shown in FIG. 8, in addition to the machine tool and the work W3, the basic configuration of a tool 30 having a cutting edge 30a on the outer periphery of the spherical body 16 is common to that shown in FIGS. Tool rotation center line R
The rotation angle position of the tool spindle 9 is determined by the motor 11 (see FIG. 1) so as to incline by a predetermined angle θ so as to have a torsional relationship with respect to.

As shown in FIG. 9, the chuck 6 of the machine tool
With respect to the axis Q of the workpiece W2
The tool inclination angle θ with respect to the work axis Q is determined so that the zero cutting edge 30a is inclined with respect to both the work axis Q and the tool rotation center line R in a torsional relationship.

In order to obtain the inclination angle θ of the tool rotation center line R with respect to the axis Q of the work, as shown in FIG.
First, the surface roughness of the flank adjacent to the cutting edge 30a of the tool 30 is measured and recorded using a known roughness measuring device in the same procedure as in FIG. 4, and is printed out as a roughness curve (step). S1, S2). FIG. 11 shows an example of a roughness curve obtained by measuring the surface roughness of the flank. Then, for the roughness curve of FIG. 11, the height H from the bottom of the valley to the peak and the interval L between the peaks are obtained. As for how to ask,
Similarly to the above, for example, combinations of valley bottoms and peaks up to the third in descending order of height are selected, and their heights H1, H
, H3 and the distances L1, L2, L3 between the peaks are obtained, and as an average thereof, H = (H1 + H2 + H
3) / 3 and L = (L1 + L2 + L3) / 3 are obtained (step S3).

Next, the cutting edge 3 is determined from the instruction drawing of the tool 30 and the like.
0a, the diameter of the spherical body 16 of the tool 30 is read, and based on the H and L dimensions and the diameter M of the tool 30, the work axis is calculated using the equation (2) as in steps S4 and S5 in FIG. The inclination angle θ of the tool rotation center line R with respect to Q is calculated.

[0042]

(Equation 2)

In the above equation, the surface roughness of the tool flank adjacent to the tool cutting edge 30a which controls the actual cutting is transferred to the cut surface K on the workpiece W side, similarly to the above-described equation (1). It is assumed that the convex portion on the workpiece cutting surface K side due to the transfer of the concave portion of the flank adjacent to the tool cutting edge 30a is also cut by the convex portion adjacent to the concave portion of the flank. In other words, the inclination angle θ of the tool 30 with respect to the workpiece axis Q is set such that, when the tool 30 is fed, the trajectory of the roughness curve at the valley bottom is traced by the ridge top near the valley bottom.

Then, this value is input to the control system of the motor 11, and as shown in FIG. By rotating the tool 30 around the tool rotation center line R by 13 and giving the feed, the concave arc-shaped surface K of the work W2 is continuously cut as a cut finish surface.

As described above, by installing the tool rotation center line R at an angle θ with respect to the workpiece axis Q,
As compared with the case of FIG. 7, the surface roughness of the cut finished surface K of the work W2 can be surely made smaller than the surface roughness of the tool flank, and the surface roughness accuracy of the cut finished surface K is dramatically improved.

In the above embodiment, the tool is fed in the tangential direction (Y direction). However, the present invention is not limited to this.
A feeder for moving the tool in the direction (vertical direction, cutting direction) is provided, and the two feeders are used based on the moving speed Vy in the Y direction and the moving speed Vx in the X direction obtained in step S5 of the flowchart of FIG. Of course, the tools can be controlled.

[Brief description of the drawings]

FIG. 1 is a front view of a machine tool according to a first embodiment of the present invention.

FIG. 2 is a plan view of FIG. 1;

3A and 3B are diagrams showing details of the first embodiment, wherein FIG. 3A is an enlarged plan view of a main part of FIG. 1, and FIG. 3B is a diagram of FIG.

FIG. 4 is a flowchart showing a processing procedure in FIG. 3;

FIG. 5 is a roughness curve diagram of a flank adjacent to the tool cutting edge of FIG. 3;

FIG. 6 is a front view of a machine tool according to a second embodiment of the present invention.

7A and 7B are diagrams showing details of the second embodiment, in which FIG. 7A is an enlarged plan view of a main part of FIG. 6, and FIG. 7B is a diagram of FIG.

FIG. 8 is a front view of a machine tool according to a third embodiment of the present invention.

9A and 9B are views showing details of the third embodiment, wherein FIG. 9A is an enlarged plan view of a main part of FIG. 8, and FIG. 9B is a view of FIG.

FIG. 10 is a flowchart showing a processing procedure in FIG. 9;

FIG. 11 is a roughness curve diagram of a flank adjacent to the tool cutting edge of FIG. 9;

FIG. 12 is an enlarged explanatory view of a main part showing a conventional general turning method.

FIG. 13 is an enlarged explanatory view of a main part showing another conventional turning method.

[Explanation of symbols]

 6 Chuck 9 Tool spindle 10 Tool 10a Cutting edge 16 Spherical body 20 Tool 20a Cutting edge 30 Tool 30a Cutting edge K ... Concave arcuate surface Q ... Work axis R ... Tool rotation center line S ... Cutting surface W: Work W1: Work W2: Work

Claims (5)

[Claims] In a turning method for cylindrically cutting the outer periphery of a work, a tool having a straight cutting edge is arranged so as to be inclined so that the cutting edge is twisted with respect to the work axis. A turning method comprising: moving a tool from an outer peripheral side of a work in an axial direction of a work so as to obtain a cutting amount; and performing a cutting process by feeding the tool in a tangential direction of a finished surface of the work. 2. The turning method according to claim 1, wherein prior to cutting, the surface roughness of the flank adjacent to the tool cutting edge is measured in advance, and the height of the roughness curve from the valley bottom to the peak is measured. And the distance between the peaks and the machining diameter of the workpiece, based on the machining path size of the workpiece, the above-mentioned trajectory necessary to trace the passage locus of the valley bottom equivalent portion of the roughness curve at the time of tool feed application near the valley bottom. A turning method comprising calculating a ratio between a moving speed in a tangential direction and a moving speed in a work axis direction, and setting a tilt angle of a tool so as to be a ratio of the calculated moving speed. 3. A turning tool for cutting a concave arc-shaped surface on the outer periphery of a workpiece by giving a rotary feed to the tool itself, wherein a spherical body having a curvature corresponding to the concave arc-shaped surface has a straight line passing through the center thereof. A single tool rotation center line is set, and a continuous cutting edge is formed along the spherical surface, and the cutting edge is inclined so as to have a torsion relationship with respect to each of the work axis and the tool rotation center line. A turning tool characterized by having been turned on. 4. A turning method using a tool according to claim 3, wherein the axis of the workpiece to be machined and the tool rotation center line are in a parallel state, and the tool is rotated around the tool rotation center line. A turning method characterized in that cutting is performed by giving a feed according to. 5. A turning method using a tool according to claim 3, wherein prior to the cutting, the surface roughness of the flank adjacent to the tool cutting edge is measured in advance, and from the valley bottom of the roughness curve. Based on the height to the peak, the interval between the peaks, and the diameter of the tool spherical portion including the cutting edge, the path of passage of the valley bottom equivalent part of the roughness curve at the time of tool rotation is determined by the peak summation part near the valley bottom. Calculate the inclination angle of the tool rotation centerline with respect to the workpiece axis required for tracing, and incline the tool so that the angle of the tool rotation centerline with respect to the workpiece axis is the calculated inclination angle. A turning method characterized in that a feed is given by rotating a tool around a tool rotation center line to perform cutting.