Machining method, machine tool, cutting tool, and cutting insert

Abstract

The invention provides a machining method, a machine tool, a cutting tool and a cutting insert. In this machining method for performing cutting machining by moving a workpiece (W) and a cutting tool (11) relative to each other, the cutting tool (11) provided with a cutting insert (28) having a first curved section (40a) is used to position a connection section (40b) at the tip in the cutting direction orthogonal to the relative movement direction during the cutting machining, and the cutting tool (11) is used to perform the cutting machining. A second curved section (40c) formed continuously with the first curved section (40a) and having a smaller curvature than the first curved section (40a); and a connecting section (40b) that connects the first curved section (40a) and the second curved section (40c).

Description

Technical Field

[0001] The invention relates to a machining method, a machine tool, a cutting tool and a cutting insert. Background Art

[0002] As is known to all, there are blades with wiper edges and scraper blades as finishing tools for cutting, but when using these tools, since the contact portion with the object to be processed, that is, the material to be cut, becomes wider, it is easy to generate heat. Therefore, for example, it is possible to use an ISO standard blade and perform processing in the contact portion of its blade tip, but while reducing cutting resistance and suppressing heat generation, there is also the possibility of deteriorating the surface roughness.

[0003] Patent Document 1 discloses a tool in which the shape of the blade tip is divided into two parts: a blade tip in contact with a transverse cutting edge and a blade tip in contact with a front cutting edge, and the curvature radius of the blade tip in contact with the front cutting edge is larger than the curvature radius of the blade tip in contact with the transverse cutting edge, and a straight line connecting the curvature centers of the two blade tips is parallel to the transverse cutting edge. However, in order to be parallel to the transverse cutting edge, the blade tip in contact with the front cutting edge needs to be lengthened, and therefore, there is a case where it is difficult to form such a blade tip on an ISO standard blade, for example.

[0004] In addition, Patent Document 2 discloses a cutting machine that can cut a cutting tool mounted on the front end of a turret tool post shaft at the same tool tip position, i.e., the same cutting angle, relative to a machining surface. However, even if the increase in cutting resistance can be suppressed, there is a possibility that the surface roughness may be deteriorated.

[0005] Prior Art Literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Utility Model Publication No. 55-165701

[0008] Patent Document 2: Japanese Utility Model Application Laid-Open No. 2002-254273 Summary of the invention

[0009] Problems to be solved by the invention

[0010] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a machining method, a machine tool, a cutting tool, and a cutting insert capable of suppressing an increase in cutting resistance and making the surface roughness appropriate.

[0011] To solve the problem

[0012] According to one embodiment of the present invention, there is provided a processing method, which performs cutting processing by relatively moving a processing object and a cutting tool, and is characterized in that the cutting processing is performed by positioning a connecting portion at the front end of a cutting direction orthogonal to the relative movement direction during cutting using the cutting tool having a cutting portion, wherein the cutting portion comprises a first curved portion; a second curved portion formed continuously with the first curved portion and having a smaller curvature than the first curved portion; and the connecting portion connecting the first curved portion and the second curved portion.

[0013] In addition, according to one embodiment of the present invention, there is provided a machine tool which performs cutting processing by relatively moving a processing object and a cutting tool, and is characterized in that it comprises a posture changing device and a control device, wherein the posture changing device changes the posture of at least either the processing object or the cutting tool; the control device operates the posture changing device in the following manner, i.e., the cutting tool having a cutting portion positions the connecting portion at the front end of the cutting direction orthogonal to the relative movement direction during cutting processing to perform cutting processing, and the cutting portion comprises a first curved portion; a second curved portion formed continuously with the first curved portion and having a smaller curvature than the first curved portion; and the connecting portion connecting the first curved portion and the second curved portion.

[0014] Furthermore, according to one embodiment of the present invention, there is provided a cutting tool, which is used in cutting processing and is characterized in that it comprises a base, a tool portion and a cutting portion, wherein the base has a shank portion mounted on a machine tool at one end; the tool portion is mounted at the other end of the above-mentioned base; the cutting portion is arranged on the above-mentioned tool portion and has a first curved portion; a second curved portion formed continuously with the above-mentioned first curved portion and having a smaller curvature than the above-mentioned first curved portion; and a connecting portion connecting the above-mentioned first curved portion and the above-mentioned second curved portion and located at the front end of the above-mentioned tool portion.

[0015] According to one embodiment of the present invention, there is provided a cutting insert, which is formed in a plate shape having an upper surface, a lower surface and a side surface, and has a fixed portion for fixing to a cutting tool during cutting processing, and is characterized in that the cutting insert has a corner portion, the corner portion having a first curved portion formed along the side surface; a second curved portion formed continuously with the first curved portion and having a smaller curvature than the first curved portion; a connecting portion connecting one end of the first curved portion and the second curved portion; and a transverse cutting edge formed on one side of the other end of the first curved portion, wherein the cutting processing is performed by positioning the connecting portion in a front end of a cutting direction orthogonal to a relative movement direction during cutting processing, and an angle formed by a line connecting the center of curvature of the first curved portion and the center of curvature of the second curved portion and the transverse cutting edge as viewed from the upper surface or the lower surface is a transverse cutting edge angle.

[0016] Effects of the Invention

[0017] According to a processing method related to one embodiment of the present invention, after the processing object is processed by the first curved portion, the groove height of the processing surface can be lowered by processing by the second curved portion having a smaller curvature than the first curved portion. Therefore, the surface roughness of the processed object after processing can be made appropriate. In addition, by positioning the connecting portion at the front end of the cutting direction orthogonal to the relative movement direction during cutting processing, that is, by positioning the connecting portion in a manner that the connecting portion contacts the processing surface of the processing object for cutting processing, the contact portion between the cutting tool and the processing surface of the processing object can be suppressed from widening. Therefore, the increase in cutting resistance can be suppressed.

[0018] According to a machine tool related to one embodiment of the present invention, by processing the processing object by the first curved portion and then processing it by the second curved portion with a smaller curvature than the first curved portion, the groove height of the processing surface can be lowered. Therefore, the surface roughness of the processing object after processing can be made appropriate. In addition, the machine tool is equipped with a posture changing device and a control device for controlling the posture changing device. Therefore, by operating the posture changing device through the control device, the connecting portion can be positioned at the front end of the cutting direction orthogonal to the relative movement direction during cutting, that is, the posture of at least one of the processing object or the cutting tool can be changed in a manner that the connecting portion contacts the processing surface of the processing object. As a result, the contact portion between the cutting tool and the processing surface of the processing object can be prevented from widening, thereby preventing an increase in cutting resistance.

[0019] According to a cutting tool of one embodiment of the present invention, after the object to be processed is processed by the first curved portion of the cutting portion arranged in the tool portion, the height of the groove on the processing surface of the object to be processed can be lowered by processing by the second curved portion having a smaller curvature than the first curved portion. Therefore, the surface roughness of the object to be processed after processing can be made appropriate. In addition, by positioning the connecting portion at the front end of the cutting direction orthogonal to the relative moving direction during cutting processing, that is, by positioning the connecting portion in a manner that the connecting portion contacts the processing surface of the object to be processed to perform cutting processing, the contact portion between the cutting tool and the processing surface of the object to be processed can be suppressed from widening. Therefore, the increase in cutting resistance can be suppressed.

[0020] According to a cutting insert of one embodiment of the present invention, after the object to be processed is processed by the first curved portion of the corner, the height of the groove on the processing surface of the object to be processed can be lowered by processing it by the second curved portion having a smaller curvature than the first curved portion. Therefore, the surface roughness of the object to be processed after processing can be made appropriate. In addition, by positioning the connecting portion at the front end of the cutting direction orthogonal to the relative movement direction during cutting processing, that is, by positioning the connecting portion in contact with the processing surface of the object to be processed to perform cutting processing, it is possible to suppress the widening of the contact portion between the cutting tool and the processing surface of the object to be processed. Therefore, it is possible to suppress the increase in cutting resistance. Furthermore, since the angle formed by the line connecting the center of curvature of the first curved portion and the center of curvature of the second curved portion and the transverse cutting edge can be used as the transverse cutting edge angle, the degree of freedom in setting the length dimension and the radius of curvature of the first curved portion and the second curved portion can be increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A side view showing the machine tool according to the first embodiment.

[0022] Figure 2 A side view of a cutting tool according to the present embodiment is shown.

[0023] Figure 3 A perspective view showing a cutting insert according to the present embodiment.

[0024] Figure 4 A plan view showing a corner portion according to the present embodiment.

[0025] Figure 5 An explanatory diagram showing turning processing performed by a machine tool.

[0026] Figure 6 An explanatory diagram showing a cutting process performed by a cutting insert.

[0027] Figure 7 This figure shows the tapered turning process in which the machine tool changes its posture.

[0028] Figure 8 A side view of a cutting tool according to a second embodiment is shown.

[0029] Fig. 9 A side view showing a corner portion according to the third embodiment.

[0030] Fig.10 An explanatory diagram showing a turning process performed by a machine tool according to a third embodiment. DETAILED DESCRIPTION

[0031] Modes for carrying out the invention

[0032] Hereinafter, a processing method, a machine tool, a cutting tool, and a cutting insert according to the embodiment will be described with reference to the accompanying drawings. The same reference numerals are given to the same or corresponding elements, and repeated descriptions are omitted. For ease of understanding, the scale of the drawings may be changed for description.

[0033] (First embodiment)

[0034] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Figure 1 1 shows a side view of a machine tool according to the first embodiment. The machine tool 10 according to the present embodiment is a machine tool 10 for performing turning processing by relatively moving a cutting tool 11 and a workpiece W as a rotating processing object along a feed direction DR as a relative movement direction. The machine tool 10 includes a bed 12 as a base fixed on the floor surface of a factory. In addition, the machine tool 10 includes a workpiece spindle 16 and a column 14. The workpiece spindle 16 is arranged in the left-right direction of the upper side of the bed 12, that is, on the left side in the Y-axis direction ( Figure 1 The column 14 is upright on the right side of the bed 12 in the Y-axis direction ( Figure 1 on the right side of the drawing and secure it.

[0035] A saddle 18 for moving the cutting tool 11 along the Y-axis direction and the Z-axis direction is arranged on the front side of the column 14, that is, on the left side in the Y-axis direction. As a result, the cutting tool 11 and the workpiece spindle 16 can be relatively moved along the X-axis direction and the Z-axis direction as the feed direction DR. In addition, the machine tool 10 is equipped with a Y-axis feed device (not shown) for relatively moving the cutting tool 11 and the workpiece spindle 16 along the Y-axis direction as the feed direction DR.

[0036] On the front side of the saddle 18, i.e., on the left side in the Y-axis direction, a posture changing device 20 having a rotation axis 20a extending along the X-axis direction is arranged, and a tool spindle 22 for mounting the cutting tool 11 is connected to the rotation axis 20a. The posture changing device 20 is configured to rotate the tool spindle 22 connected thereto around the rotation axis 20a. Therefore, the cutting tool 11 mounted on the tool spindle 22 can be tilted relative to the Y-axis direction and the Z-axis direction. In this way, the portion of the cutting tool 11 that contacts the workpiece W during cutting, i.e., the connection portion 40b described later (see Figure 3 ) position. In addition, the posture changing device 20 may further include another rotation axis orthogonal to the rotation axis 20a and parallel to the Y axis between the saddle 18. Thus, the posture of the cutting tool spindle 22 can be changed more freely.

[0037] In the following description, the posture changing device 20 is described as being connected to the tool spindle 22 on which the cutting tool 11 is mounted, but the present invention is not limited thereto and may be connected to a workpiece spindle on which a workpiece is mounted, or may be connected to both the tool spindle and the workpiece spindle.

[0038] like Figure 2 As shown, it is mounted on the tool spindle 22 (see Figure 1 ) has a base 23 and a tool portion 26. The base 23 has a shank 24 mounted at one end, that is, the end on the tool spindle 22 side, and the tool portion 26 is mounted at the other end of the base 23, that is, the end on the opposite side to the tool spindle 22. The tool portion 26 has a tool mounting portion 26b mounted on the base 23 and a rod-shaped shaft portion 26a connected to the tool mounting portion 26b. A cutting insert 28 is fixedly mounted on the front end of the shaft portion 26a by a screw, and the cutting insert 28 serves as a cutting portion for cutting a workpiece W. In addition, here, the cutting insert 28 is fixedly mounted by a screw as the cutting portion of the cutting tool 11, but it is not limited to this. The cutting portion can also be mounted in other ways such as being integrated with the shaft portion or silver brazing.

[0039] like Figure 1 As shown, the machine tool 10 includes a control device 30 electrically connected to the posture changing device 20. The control device 30 can change the rotation of the tool spindle 22 connected thereto, that is, the posture of the cutting tool 11, by operating the posture changing device 20. In addition, the machine tool 10 has a load detection component 32, which is electrically connected to the cutting tool 11, the workpiece spindle 16 and the control device 30, and can detect the load of the cutting tool 11 during cutting.

[0040] The load detection unit 32 is disposed on the workpiece spindle 16, for example, and is electrically connected to a motor (not shown) that rotates the workpiece W, and is configured to detect the torque or current value of the motor. Therefore, when the control device 30 determines that the torque or current value detected by the load detection unit 32 exceeds a predetermined threshold value and the load on the workpiece spindle 16 is high, it is estimated that the position of the cutting insert 28 is inappropriate, and the posture changing device 20, the saddle 18, and the Y-axis feed device are operated to change the posture of the cutting tool 11. This can suppress an increase in cutting resistance.

[0041] In addition, the following description of the load detection component 32 detecting the torque or current value of the motor configured on the workpiece spindle 16, but is not limited to this. The load detection component, for example, when the cutting tool is rotated, can also be configured to detect the torque or current value of the motor used to rotate the cutting tool. When both the workpiece spindle and the cutting tool are rotated, it can also be configured to detect the torque or current value of the motors respectively configured on both of them.

[0042] A position detection unit 34 is disposed on the working spindle 16 side of the machine tool 10, and the position detection unit 34 can detect the position of the cutting insert 28, specifically, the position of the connecting portion 40b. The position detection unit 34 can detect the position of the connecting portion 40b in the machine tool 10 by, for example, a photographic unit such as a camera, a position sensor, etc. Thus, the actual position of the connecting portion 40b can be accurately grasped while also considering the manufacturing errors of the cutting tool 11 and the cutting insert 28, the installation errors thereof, etc. Moreover, without being limited to this, the machine tool can also record and manage the dimensional information of the cutting tool and the cutting insert in the tool data management unit in advance, and detect the position of the connecting portion based on the dimensional information.

[0043] Figure 3 1 is a perspective view showing a cutting insert 28. Here, the cutting insert 28 is formed in a triangular plate shape having an upper surface 28a, a lower surface 28b, and a side surface 28c connecting the outer periphery of the upper surface 28a and the outer periphery of the lower surface 28b. Therefore, the cutting insert 28 has corners 40 at three locations. In addition, without limitation to this, the cutting insert may be formed in a rectangular plate or a polygonal plate shape, for example, and may have corners at four or more locations. In addition, a hole 42 as a fixed portion for fixing to the shaft portion 26a of the cutting tool 11 is formed in the central portion of the cutting insert 28. In addition, here, it is explained that the cutting insert 28 is fixed to the threaded hole of the shaft portion 26a of the cutting tool 11 by a screw member, but without limitation to this, the cutting insert may also be fixed to the shaft portion by pressing the upper surface, one side surface, with a clamping claw formed on the shaft portion and using the lower surface, the other side surface, as a seat surface.

[0044] Figure 4 : shows the corner 40 of the cutting insert 28. The corner 40 has a first curved portion 40a formed along the side surface 28c; a second curved portion 40c formed continuously with the first curved portion 40a; a curvature smaller than that of the first curved portion 40a; and a connecting portion 40b connecting one end of the first curved portion 40a and the second curved portion 40c. In addition, the corner 40 has a cross-cutting edge 44, which is formed in a straight line at the end on the opposite side to the connecting portion of the first curved portion 40a when viewed from the top 28a or the bottom 28b side. In addition, the front cutting edge 46 is formed in a straight line so as to be continuous with the end on the opposite side to the connecting portion 40b of the second curved portion 40c.

[0045] The dimensions of the corner portion 40 are set as follows. First, the front cutting edge angle α, the blade angle β, the curvature radius R1 of the first curved portion 40a, and the curvature radius R2 of the second curved portion 40c are determined according to the processing purpose. Next, the length dimension of the second curved portion 40c and the tangent point of the second curved portion 40c and the front cutting edge 46 are determined. Finally, the end point of the second curved portion 40c, that is, the connecting portion 40b of the first curved portion 40a and the second curved portion 40c is determined according to the length dimension of the second curved portion 40c. The center of curvature C1 of the first curved portion 40a is determined by the perpendicular line drawn from the connecting portion 40b to the second curved portion 40c and the curvature radius R1 of the first curved portion 40a whose curvature radius is shorter than that of the second curved portion 40c. In this way, a continuous corner portion 40 having a composite blade tip combining the first curved portion 40a and the second curved portion 40c can be formed. The dimensions of the first curved portion 40a and the second curved portion 40c set in this way and the processing length X of the corner portion 40 satisfy the following relationship.

[0046] a=(R2-R1)×sinα (1)

[0047] b=R1 / sinβ (2)

[0048] c=[R2-{(R2-R1)×cosα}] / tanβ (3)

[0049] X=a+b+c (4)

[0050] Here, in the case of a general cutting insert 28, it is appropriate to set the curvature radius R2 of the second curved portion 40c to 10 mm or less. However, the present invention is not limited thereto, and the curvature radius of the second curved portion may be set to 10 mm or more depending on the size of the workpiece and the purpose of processing.

[0051] The cutting insert 28 is mounted on the shaft 26a in such a manner that the connection portion 40b is located at the front end in the axial direction of the cutting tool 11. Thus, the cutting process can be performed by positioning the connection portion 40b in such a manner that the connection portion 40b is located at the front end in the cutting direction orthogonal to the feed direction DR during cutting, that is, in such a manner that the connection portion 40b abuts against the machined surface MS of the workpiece W. In addition, the front cutting edge angle α of the cutting insert 28 mounted on the shaft 26a in this way can be set to a desired front cutting edge angle α. Furthermore, in such a manner that the connection portion 40b is located at the front end in the cutting direction orthogonal to the feed direction DR during cutting, that is, in such a manner that the connection portion 40b abuts against the machined surface MS of the workpiece W, the straight line connecting the curvature center C1 of the first curved portion 40a and the curvature center C2 of the second curved connecting portion 40c is perpendicular to the machined surface MS of the workpiece W, and the angle γ formed by the straight line connecting the curvature center C1 of the first curved portion 40a and the curvature center C2 of the second curved portion 40c and the infeed edge 44 becomes the infeed edge angle γ.

[0052] Hereinafter, cutting processing using the processing method, the machine tool 10, the cutting tool 11, and the cutting insert 28 according to the present embodiment will be described, and their functions and effects will be described.

[0053] Figure 5 1 shows a turning process using a cutting tool 11. Figure 6 This indicates that the amount of workpiece W removed is increased by performing cutting using the corner portion 40 that makes the connection portion 40 b abut against the machined surface MS of the workpiece W. Figure 6 In FIG. 1 , the cutting insert 28 positioned in this way is indicated by the dashed line (front) and the solid line (rear) so that the corners 40 at the front and rear are moved only by the length Fz in the feed direction DR every time the workpiece W rotates one turn. At this time, the corner 40 of the cutting insert 28 cuts the workpiece W only by the cutting depth t within the contact range CR1. At this time, the remaining portion RP of the groove height Rz is generated.

[0054] exist Figure 6 , for comparison, a single corner portion SG having a single cutting edge formed only by the first curved portion 40a is shown. The single corner portion SG cuts the workpiece W only at the cutting depth t within the contact range CR2. At this time, the remaining portion generated is increased by only the portion AP. As can be seen from these comparisons, since the amount of cutting is increased by the corner portion 40 of the cutting insert 28 having the composite cutting edge, the groove height Rz of the remaining portion RP becomes lower, so that the surface roughness is suppressed from increasing, that is, the surface is suppressed from becoming rough.

[0055] Figure 7 2 shows a situation where the machine tool performs a tapered turning process by changing its posture. Even in the case of performing a tapered turning process, the control device 30 can change the posture of the cutting tool 11 by operating the posture changing device 20. Figure 4 As shown, the connection portion 40b is positioned at the front end of the cutting direction orthogonal to the feed direction DR during cutting, that is, the connection portion 40b is positioned in contact with the machined surface MS of the workpiece W for cutting.

[0056] According to the machine tool 10 having the cutting tool 11 of the present embodiment, after the workpiece W is cut by the first curved portion 40a of the cutting insert 28 disposed in the tool portion 26, the groove height Rz of the machined surface MS of the workpiece W can be reduced by cutting by the second curved portion 40c having a smaller curvature than the first curved portion 40a. Therefore, the surface roughness of the machined workpiece W can be made appropriate. In addition, by positioning the connecting portion 40b at the front end of the cutting direction orthogonal to the feed direction DR during cutting, that is, by positioning the connecting portion 40b in contact with the machined surface MS of the workpiece W for cutting, it is possible to suppress the contact portion of the cutting tool 11 with the machined surface MS of the workpiece W from becoming wider. Therefore, it is possible to suppress the increase in cutting resistance.

[0057] Furthermore, according to the machine tool 10 according to the present embodiment, the control device 30 and the load detection unit 32 are provided. Therefore, when it is determined that the torque or current value detected by the load detection unit 32 exceeds a predetermined threshold value and the load on the workpiece spindle 16 is high, the control device 30 infers that the position of the cutting insert 28 is inappropriate, and operates the posture changing device 20, the saddle 18, and the Y-axis feed device to change the posture of the cutting tool 11. Thus, it is possible to suppress an increase in cutting resistance.

[0058] Furthermore, according to the machine tool 10 according to the present embodiment, the position detection unit 34 is provided. The detection unit 34 is composed of, for example, a camera or other imaging unit, a position sensor, etc., and can detect the position of the connection portion 40b of the cutting insert 28 on the workpiece spindle 16 side of the machine tool 10. Therefore, the position detection unit 34 can detect the position of the connection portion 40b in the machine tool 10. Thus, the actual position of the connection portion 40b can be accurately grasped in consideration of manufacturing errors of the cutting tool 11 and the cutting insert 28, installation errors thereof, etc.

[0059] According to the cutting insert 28 of the present embodiment, the angle formed by the line connecting the center of curvature C1 of the first curved portion 40a and the center of curvature C2 of the second curved portion 40c and the infeed edge 44 can be made the infeed edge angle γ. Therefore, the degree of freedom in setting the length dimensions and the curvature radii R1 and R2 of the first curved portion 40a and the second curved portion 40c can be increased.

[0060] Therefore, according to the machining method, the machine tool 10 , the cutting tool 11 , and the cutting insert 28 according to the present embodiment, it is possible to make the surface roughness of the machined surface MS of the workpiece W appropriate while suppressing an increase in cutting resistance.

[0061] (Second embodiment)

[0062] Hereinafter, a milling tool 60 as a cutting tool according to a second embodiment will be described. Elements identical or corresponding to those of the first embodiment are denoted by the same reference numerals, and duplicate descriptions are omitted.

[0063] Figure 8 2 shows a milling cutter 60 to which a plurality of cutting inserts 28 are mounted. The cutter portion 62 of the milling cutter 60 includes a cutter mounting portion 62b mounted on the base 23 and a cylindrical shaft portion 62a connected to the cutter mounting portion 62b. At the front end of the shaft portion 62a, the cutting inserts 28 as cutting portions formed integrally with the shaft portion 62a are arranged at equal intervals along the circumferential direction of the shaft portion 62a.

[0064] According to the milling cutter 60 of this embodiment, Figure 6 and Figure 8 As shown in FIG. 6 , after the workpiece W is milled by the first curved portion 40a of the cutting insert 28 disposed in the tool portion 62, the groove height Rz of the machined surface MS of the workpiece W can be reduced by milling by the second curved portion 40c having a smaller curvature than the first curved portion 40a. Therefore, the surface roughness of the machined workpiece W can be made appropriate. In addition, by positioning the connection portion 40b so as to contact the machined surface MS of the workpiece W and performing cutting, the contact portion between the cutting tool 11 and the machined surface MS of the workpiece W can be prevented from widening. Therefore, the increase in cutting resistance can be suppressed.

[0065] (Third Embodiment)

[0066] Hereinafter, a cutting insert 70 as a cutting portion according to a third embodiment will be described. Elements identical or corresponding to those of the first embodiment are denoted by the same reference numerals, and duplicate descriptions are omitted.

[0067] Fig. 9 : shows the corner portion 72 of the cutting insert 70. The corner portion 72 includes a first curved portion 72a; a second curved portion 72c formed continuously with the first curved portion 72a and having a smaller curvature than the first curved portion 72a; and a connecting portion 72b connecting the end of the first curved portion 72a on the front cutting edge 46 side and the second curved portion 72c. In addition, the corner portion 72 includes a third curved portion 72d having the same curvature radius R2 and length dimension as the second curved portion 72c on the cross cutting edge 44 side of the first curved portion 72a; and a connecting portion 72b connecting the first curved portion 72a and the third curved portion 72d.

[0068] The dimensions of the corner portion 72 are set as follows. First, the front cutting edge angle α, the tool tip angle β, the curvature radius R1 of the first curved portion 72a, and the curvature radius R2 of the second curved portion 72c and the third curved portion 72d are determined in accordance with the processing purpose. Next, the length dimensions of the second curved portion 72c and the third curved portion 72d, as well as the tangent points of the second curved portion 72c and the front cutting edge 46 and the tangent points of the third curved portion 72d and the transverse cutting edge 44 are determined. Finally, the end points of the second curved portion 72c and the end points of the third curved portion 72d, that is, the connecting portion 72b with the first curved portion 72a, are determined based on the length dimensions of the second curved portion 72c and the third curved portion 72d. The center of curvature C1 of the first curved portion 72a is determined by a perpendicular line drawn at the connecting portion 72b to the second curved portion 72c or the third curved portion 72d and the curvature radius R1 of the first curved portion 72a. Thereby, the corner portion 72 in which three blade edges of the first curved portion 72a, the second curved portion 72c, and the third curved portion 72d are continuously combined can be formed.

[0069] Fig.10 1 shows a cutting process in a plurality of feed directions DR. As shown in the figure, the postures of the cutting inserts 70 mounted on the plurality of cutting tools 11 are different depending on the processing position. According to the cutting insert 70 of the present embodiment, the second curved portion 72c and the third curved portion 72d are formed symmetrically with respect to the first curved portion 72a. Therefore, it is not necessary to manage the left-hand side (Japanese: ), right hand side (Japanese: ), cutting processing in various directions can be performed by one type of cutting insert 70. Therefore, cutting processing can be efficiently performed without replacing each cutting insert 70 according to the feeding direction.

[0070] Although the embodiments of the machining method, the machine tool 10 , the cutting tool 11 , and the cutting insert 28 are described above, the present invention is not limited to the above embodiments. It is understood that those skilled in the art can make various modifications to the above embodiments.

[0071] Explanation of symbols

[0072] 10: Machine tools

[0073] 11: Cutting tools

[0074] 16: Workpiece spindle (processing object installation part)

[0075] 20: Posture change device

[0076] 23: Base

[0077] 24: Handle

[0078] 26: Tool Department

[0079] 28: Cutting insert (cutting part)

[0080] 28a: Above

[0081] 28b: Below

[0082] 28c: Side

[0083] 30: Control device

[0084] 32: Load detection component

[0085] 34: Position detection device

[0086] 40: Corner

[0087] 40a: First curve

[0088] 40b: Connection

[0089] 40c: Second curve

[0090] 42: Hole (fixed part)

[0091] 44: Crosscutting edge

[0092] 60: Milling tools (cutting tools)

[0093] 62: Tool Department

[0094] 70: Cutting insert (cutting part)

[0095] 72: Corner

[0096] 72a: First curve

[0097] 72b: Connection

[0098] 72c: Second curve

[0099] 72d: Third curve

[0100] C1: Center of curvature of the first curve

[0101] C2: Center of curvature of the second curve

[0102] DR: Feed direction (relative moving direction)

[0103] W: workpiece (processing object).

Claims

1. A machining method, wherein a machining object and a cutting tool are moved relative to each other to perform a cutting machining, characterized in that: The cutting tool having a cutting portion is used to position the connecting portion at the front end of the cutting direction orthogonal to the relative movement direction during the cutting process, and the cutting portion has a first curved portion; a second curved portion formed continuously with the first curved portion and having a smaller curvature than the first curved portion; and the connecting portion connecting the first curved portion and the second curved portion.

2. A machine tool that performs cutting processing by relatively moving a processing object and a cutting tool, characterized in that: Equipped with posture changing device and control device, The posture changing device changes the posture of at least one of the above-mentioned processing object or the above-mentioned cutting tool; The control device operates the posture changing device in the following manner, that is, the cutting tool having a cutting portion positions the connecting portion at the front end of the cutting direction orthogonal to the relative movement direction during cutting to perform cutting, and the cutting portion has a first curved portion; a second curved portion formed continuously with the first curved portion and having a smaller curvature than the first curved portion; and the connecting portion connecting the first curved portion and the second curved portion.

3. The machine tool according to claim 2, characterized in that: The posture changing device is disposed on at least one of a spindle on which the cutting tool is mounted or a processing object mounting portion on which the processing object is mounted.

4. The machine tool according to claim 3, characterized in that: A position detection unit capable of detecting the position of the connection portion is further provided.

5. The machine tool according to any one of claims 2 to 4, characterized in that: The machine also includes a load detection unit capable of detecting the load during cutting.

6. A cutting tool used in cutting processing, characterized in that: It has a base, a tool part and a cutting part. The base has a handle at one end thereof for mounting on a machine tool; The cutter portion is mounted on the other end of the base portion; The cutting portion is arranged on the tool portion, and comprises a first curved portion; a second curved portion which is continuously formed with the first curved portion and has a smaller curvature than the first curved portion; and a connecting portion which connects the first curved portion and the second curved portion and is located at the front end of the tool portion.

7. The cutting tool according to claim 6, characterized in that The cutting portion is arranged such that the connecting portion is located at a front end of at least one of an axial direction and a radial direction of the cutting tool.

8. The cutting tool according to claim 6 or 7, characterized in that The above-mentioned cutting tool is a turning tool for machining a rotating machining object.

9. The cutting tool according to claim 6 or 7, characterized in that The cutting tool is a milling tool that processes a processing object while rotating.

10. A cutting insert formed in a plate shape having an upper surface, a lower surface and side surfaces, and having a fixed portion for fixing to a cutting tool during cutting processing, characterized in that: The invention comprises a corner portion, wherein the corner portion has a first curved portion formed along the side surface; a second curved portion formed continuously with the first curved portion and having a smaller curvature than the first curved portion; a connecting portion connecting one end of the first curved portion and the second curved portion; and a cross-cutting blade formed on one side of the other end of the first curved portion, The cutting process is performed by positioning the connecting portion at the front end of the cutting direction orthogonal to the relative movement direction during the cutting process. When viewed from the upper side or the lower side, the angle formed by the line connecting the center of curvature of the first curved portion and the center of curvature of the second curved portion and the transverse cutting edge becomes the transverse cutting edge angle.

11. The cutting insert according to claim 10, characterized in that The corner portion has a third curved portion that is continuously formed at the other end of the first curved portion and has the same shape as the second curved portion.

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