JP6630423B1 - Cutting inserts, replaceable rotary cutting tools and methods of using replaceable rotary cutting tools - Google Patents

Abstract

[PROBLEMS] To provide a cutting insert with a cutting edge exchangeable rotary cutting tool using a cutting insert, which improves the machining surface accuracy of a work material such as a metal part or a die and also improves the cutting efficiency. As a cutting insert removably attached to a tip of a rotating tool body, a cutting edge for cutting a workpiece has a convex arc shape with a radius of curvature R1 at a center on the tip side. The bottom cutting edge 11, a straight cutting edge 12, which is inclined to be tangent to the end of the bottom cutting edge, and extends straight, and the straight cutting edge 12 is continuous with the end of the straight cutting edge. The outer cutting edge 13 having a convex arc shape with a radius of curvature R2 larger than the bottom cutting edge toward the center from the extension line X1 of the cutting edge is used. [Selection diagram] Fig. 1

Description

  The present invention relates to a cutting insert used for various kinds of cutting, a cutting edge-changeable rotary cutting tool using the cutting insert, and a method of using the cutting edge-changeable rotary cutting tool. In particular, while improving the machining surface precision of the work material such as metal parts and mold processing, it is also possible to improve the cutting efficiency, while improving the machining accuracy of cutting the vertical wall surface and bottom surface linearly, The feature is that these cutting processes can be performed efficiently.

  2. Description of the Related Art Conventionally, when cutting a workpiece such as a metal part or a mold, a cutting edge replaceable rotary cutting tool in which various cutting inserts are detachably attached to a tip of a rotating tool body has been used. I have.

  As such a replaceable rotary cutting tool, for example, a replaceable ball end mill disclosed in Patent Document 1 and the like is widely used.

  However, in the case of the conventional cutting edge replaceable ball end mill, it is difficult to improve the cutting efficiency while maintaining the machining surface accuracy when cutting the work material and performing upright wall machining or bottom machining. .

  That is, in the case of the conventional blade-interchangeable ball end mill, the radius of curvature of the cutting edge used for the tool diameter is basically (tool diameter / 2). To reduce the cusp height, the pitch must be set small. When machining a concave corner formed at the connection between the bottom surface and the standing wall surface of the work material, the cutting edge exchange type ball end mill has a small tool diameter and a small curvature. It is necessary to replace the ball end mill with a small-diameter cutting edge having a diameter equal to or smaller than the radius to perform the machining. In order to maintain the machining surface accuracy, the cutting efficiency has been significantly reduced.

  Conventionally, as disclosed in Patent Document 2, in a cutting edge replaceable rotary cutting tool in which a plate-shaped cutting insert is detachably attached to a tip portion of a tool body that is rotated around a central axis, As a cutting edge of the cutting insert, a bottom cutting edge which is located at the front end in the center axis direction and forms a convex arc shape, is continuous with a radially outer end of the bottom cutting edge, and has a radius of curvature greater than that of the bottom cutting edge. An outer peripheral cutting edge having a large convex arc shape, and an angle formed between a tangent at a boundary point between the bottom cutting edge and the outer peripheral cutting edge and the central axis is less than 45 degrees. The radius of curvature R1 of the bottom cutting edge is 0.3 to 10 mm, and the ratio (R2 / R1) of the radius of curvature R2 of the outer peripheral cutting edge to the radius of curvature R1 of the bottom cutting edge is 3.6 to 10 mm. 333 using a cutting insert It is draft.

  However, even in a cutting edge replaceable rotary cutting tool using a cutting insert as shown in Patent Document 2, the cutting edge of the cutting insert is located at the tip in the central axis direction and forms a convex arc-shaped bottom cutting edge. And an outer peripheral cutting edge which is continuous with the radially outer end of the bottom cutting edge and has a convex arc shape having a larger radius of curvature than the bottom cutting edge. When performing a cutting process that is close to a straight line by cutting the bottom and the bottom, it is troublesome to control using the outer peripheral cutting edge that has a convex arc shape with a large radius of curvature, and in this way the radius of curvature is Even when cutting the vertical wall surface or the bottom surface using a large convex arc-shaped outer peripheral cutting edge, increasing the feed pitch of the cutting insert in the replaceable rotary cutting tool can reduce the conventional cutting edge. Formula bow Similar to the end mill, a problem that Kasupuhaito increases has occurred.

  For this reason, even in a cutting edge replaceable rotary cutting tool using a cutting insert as shown in Patent Document 2, a cutting process in which a work material is cut so as to be almost straight with respect to an upright wall surface or a bottom surface is performed. When performing the cutting, the pitch can be made larger than that of the conventional blade-interchangeable ball end mill, but the cusp height during cutting is reduced, and the cutting that is linear with the vertical wall surface and the bottom surface with high finishing accuracy is performed. In order to perform the machining, it is still necessary to reduce the feed pitch of the rotary cutting tool with a replaceable cutting edge, and it takes a lot of time to perform a straight cutting operation with high finishing accuracy. It was difficult to perform the cutting process efficiently, and cusp height remained, albeit slightly.

JP-A-10-315031 Japanese Patent No. 6278170

  An object of the present invention is to solve the above-mentioned problems in a cutting insert used for various kinds of cutting and a cutting edge replaceable rotary cutting tool using the cutting insert.

  That is, the present invention provides a cutting insert as described above and a cutting edge replaceable rotary cutting tool using the cutting insert, which improves the machining surface accuracy of a work material such as a metal part and a die, and performs cutting. An object of the present invention is to make it possible to efficiently perform these cutting operations while improving the processing efficiency, and improving the processing accuracy of cutting the upright wall surface and the bottom surface in a straight line.

  In the cutting insert according to the present invention, in order to solve the above-described problems, in a cutting insert that is detachably attached to a tip portion of a rotating tool main body, a cutting edge for cutting a work material is used as a cutting edge. A bottom cutting edge having a convex arc shape at the center of the side, a straight cutting edge inclined and extended linearly so as to be tangent to the end of the bottom cutting edge, and an end of the straight cutting edge And a convex arc-shaped outer cutting edge having a larger radius of curvature than the bottom cutting edge so as to be closer to the center side than the extension of the straight cutting edge.

  In the cutting insert of the present invention, as the cutting edge for cutting the work material, the cutting edge is linearly inclined so as to be tangent to the end of the bottom cutting edge formed in a convex arc shape at the center on the tip side. A straight cutting edge that is extended to the end of the straight cutting edge, and is continuous with the end of the straight cutting edge. Since the arc-shaped outer peripheral cutting edge is provided, when performing a straight cutting process on the vertical wall surface or the bottom surface of the work material, the straight cutting edge is set along the machined surface of the work material, and the straight cutting edge is set. If the cutting insert is fed at a pitch within the range of the blade length, the machined surface is cut by a straight cutting edge, the generation of cusp height is suppressed, and the bottom cutting edge tangent to the straight cutting edge The corners of the machined surface are finished smoothly .

  Here, in the cutting insert of the present invention, in order to smoothly cut the connecting portion between the straight cutting edge and the outer peripheral cutting edge, the connecting portion between the straight cutting edge and the outer peripheral cutting edge is formed. Although it is preferable to make a tangent, when finishing the vertical wall surface or the bottom surface of the work material, since the outer peripheral cutting edge is cut so as not to contact the work material, the connection between the straight cutting edge and the outer peripheral cutting edge is performed. The parts need not be tangent.

  Further, in the cutting insert of the present invention, when performing the finishing work on the upright wall surface and the bottom surface of the work material as described above, if the length of the straight cutting edge is shortened, the pitch for sending the cutting insert is reduced. It is difficult to improve the efficiency of the finishing process sufficiently.On the other hand, if the length of the straight cutting edge is increased and the pitch for sending the cutting insert is increased, chatter etc. will occur during the finishing process. It is preferable that the length of the straight cutting edge is in the range of 0.2 to 10 mm because the machining accuracy is reduced, and furthermore, it is possible to prevent the cutting tool from falling due to an increase in resistance during the cutting process. In order to efficiently perform stable linear cutting while suppressing the cutting, it is preferable that the length of the straight cutting edge is in the range of 1 to 3 mm.

  Further, in the cutting insert of the present invention, when performing the linear cutting on the upright wall surface or the bottom surface of the work material as described above, the inclination angle of the straight cutting edge with respect to the center axis is set to less than 45 degrees. Is preferred. This is to make it possible to appropriately perform the cutting process in which the angle of the vertical wall surface with respect to the bottom surface of the work material is 90 degrees.

  Further, in the cutting insert of the present invention, in performing the linear cutting on the upright wall surface or the bottom surface of the work material as described above, the radius of curvature R1 of the bottom cutting edge is set to a range of 0.2 to 10 mm. Preferably, the radius of curvature R2 of the outer peripheral cutting edge is in the range of 10 to 1500 mm.

  Here, the reason why the radius of curvature R1 of the bottom cutting edge is set in the range of 0.2 to 10 mm is to secure the edge strength of the bottom cutting edge and to appropriately process a small corner portion by the bottom cutting edge. That is to ensure. The reason why the radius of curvature R2 of the outer peripheral cutting edge is set in the range of 10 to 1500 mm is that when the radius of curvature R2 of the outer peripheral cutting edge exceeds 1500 mm, resistance during cutting increases and the cutting tool falls down. On the other hand, when the radius of curvature R2 of the outer peripheral cutting edge is less than 10 mm, the cusp height becomes large, and the processing pitch cannot be increased. In addition, in order to sufficiently suppress an increase in resistance during cutting and to reduce the cusp height and increase the processing pitch, the radius of curvature R2 of the outer peripheral cutting edge is set to a range of 50 to 1000 mm. More preferred.

  Further, in the rotary cutting tool with replaceable cutting edge of the present invention, the above-mentioned cutting insert is detachably attached to a tip portion of a tool body that rotates about a central axis.

  Then, when finishing the machined surface of the work material using the cutting edge replaceable rotary cutting tool of the present invention, the straight cutting at the cutting edge of the cutting insert attached to the tip of the tool body is performed. Set the tool body so that the blade is along the work surface of the work material, send this tool body at a pitch within the range of the length of the straight cutting edge, and finish the work surface of the work material can do.

  The present invention provides a cutting insert that is detachably attached to a distal end portion of a tool body that rotates about a central axis, and as a cutting edge for cutting a work material, a convex arc-shaped central portion on the distal end side. A straight cutting edge that is inclined and extends linearly so as to be tangent to the end of the formed bottom cutting edge is provided, and is extended so as to be continuous with the end of the straight cutting edge. Since a convex arc-shaped outer peripheral cutting edge having a larger radius of curvature than the bottom cutting edge is provided so as to be directed toward the center from the line, when cutting a vertical wall surface or a bottom surface of a work material in a straight line, When the straight cutting edge is set along the machined surface of the work material and the cutting insert is sent at a pitch within the range of the length of the straight cutting edge, the machined surface is cut by the straight cutting edge. The remaining part is cut properly and the cusp height With live is suppressed, the corners of the processing surface comes to be smoothly finished by straight cutting edge and the tangent to the bottom cutting edge.

  As a result, in the cutting edge replaceable rotary cutting tool using the cutting insert according to the present invention, it is possible to improve the machining surface accuracy of a work material such as a metal part or a die, and to improve the cutting efficiency. In addition, it is possible to perform these cutting operations efficiently while improving the processing accuracy of cutting the vertical wall surface and the bottom surface in a straight line.

In the embodiment of the present invention, a cutting insert used for a cutting edge-exchangeable rotary cutting tool is shown, (A) is a schematic front view of the cutting insert, and (B) shows a cutting edge portion in the cutting insert. It is a schematic front view. FIG. 2 is a partial schematic explanatory view showing a state in which the cutting insert is attached to a tip end portion of a tool main body in the blade-tip-exchangeable rotary cutting tool according to the embodiment of the present invention. In cutting the upright wall surface of the work material using the cutting insert attached to the cutting edge replaceable rotary cutting tool according to the embodiment, the upright wall surface of the work material is cut by the outer peripheral cutting edge in the cutting insert. It is the partial schematic explanatory drawing which showed the state which performs cutting. In cutting the vertical wall surface of the work material using the cutting insert attached to the cutting edge replaceable rotary cutting tool according to the embodiment, the cutting is performed by the outer peripheral cutting edge in the cutting insert as shown in FIG. The standing wall surface of the work material after cutting is cut by the straight cutting edge in the cutting insert to cut the standing wall surface in a straight line, and to cut the remaining corner at the end of the standing wall cutting. It is the partial schematic explanatory drawing which showed. It is the schematic front view which showed the cutting edge part of the cutting insert in the example of a change used for the cutting edge exchange type rotary cutting tool in embodiment of this invention.

  Hereinafter, a cutting insert according to an embodiment of the present invention, a cutting edge-changeable rotary cutting tool using the cutting insert, and a method of using the cutting edge-changeable rotary cutting tool will be specifically described with reference to the accompanying drawings. In addition, the cutting insert in the present invention, the method of using the cutting edge replaceable rotary cutting tool and the cutting edge replaceable rotary cutting tool using the cutting insert is not particularly limited to those shown in the following embodiment, the gist of the gist The present invention can be appropriately changed within the range not changed.

  In this embodiment, FIGS. 1A and 1B show a cutting insert 10 that is detachably attached to the tip of a tool body 2 in a cutting edge replaceable rotary cutting tool 1 that rotates about a central axis Y. As shown in FIG. 1B, a convex arc-shaped bottom cutting edge 11 is provided at the center of the front end side of the central axis Y so as to extend on both sides thereof, and the bottom cutting edge 11 is tangent to both ends. The straight cutting edges 12 are provided so as to extend in a straight line so as to be continuous with the ends of the straight cutting edges 12 which are linearly extended. An outer peripheral cutting edge 13 having a convex arc shape having a larger radius of curvature than the bottom cutting edge 11 is provided so as to be directed toward the central axis Y rather than X1, and the cutting insert 10 becomes flat. In the center, this cutting The mounting holes 14 for mounting the insert 10 to the distal end of the tool body 2 of the indexable rotary cutting tool 1 is provided.

  And in the said cutting insert 10 in this embodiment, the curvature radius R1 in the said convex arc-shaped bottom cutting edge 11 is the range of 0.2-10 mm as mentioned above, and in this embodiment, And the length L of the straight cutting edge 12 that is inclined and extended linearly so as to be tangent to both ends of the bottom cutting edge 11 is set to be about 2 mm. Thus, in this embodiment, the length L is set to about 1.8 mm, and the inclination angle θ1 of these straight cutting edges 12 with respect to the center axis Y is As described above, the angle is less than 45 degrees, and in this embodiment, the inclination angle θ1 is set to about 40 degrees.

  In the cutting insert 10 according to this embodiment, the outer peripheral cutting edge 13 does not tangent to the linear cutting edge 12 so as to be closer to the center axis Y than the extension line X1 of the linear cutting edge 12. In this embodiment, the inclination angle θ2 of the tangent line X2 to the central axis Y at the central portion of each outer peripheral cutting edge 13 is set to about 30 degrees in this embodiment, and the radius of curvature R2 of each outer peripheral cutting edge 13 is set as described above. The radius of curvature R1 is set to be larger than the radius of curvature R1 of the bottom cutting edge 11, and as described above, the radius of curvature R2 is in the range of 10 to 1500 mm. In this embodiment, the radius of curvature R2 is set to approximately 50 mm.

  As shown in FIG. 2, in the blade-replaceable rotary cutting tool 1 according to this embodiment, the cutting insert 10 as described above is attached to the distal end portion of the tool body 2 that rotates about the center axis Y. In this state, the cutting insert 10 is inserted into the mounting hole 14 provided in the cutting insert 10 so that the cutting insert 10 is attached to the tip end of the tool body 2. It is fixed so as to be sandwiched between the mounting portions 3.

  Then, the upright wall surface Wa of the work material W such as a metal part or a die is cut using the cutting edge replaceable rotary cutting tool 1 in which the cutting insert 10 is attached to the tip of the tool body 2 as described above. In this case, for example, as shown in FIG. 3, the center axis Y of the tool main body 2 to which the cutting insert 10 is attached is set to the center axis of the tangent line X2 at the center of the outer peripheral cutting edge 13 provided in the cutting insert 10. In the state where the outer peripheral cutting edge 13 where the radius of curvature R2 is about 50 mm and the center portion of the outer peripheral cutting edge 13 is along the upright wall surface Wa to be cut is tilted by about 30 degrees corresponding to the tilt angle θ2 with respect to Y, The tool body 2 is moved along the vertical wall surface Wa at a predetermined pitch pa while rotating, and the vertical wall surface Wa of the workpiece W is cut by the outer peripheral cutting edge 13 of the cutting insert 10.

  When the upright wall surface Wa is cut by the outer peripheral cutting edge 13 of the cutting insert 10 in this manner, the outer periphery is moved to a portion moved along the upright wall surface Wa at a predetermined pitch pa while rotating the tool body 2. The cusp height CH that is not cut by the cutting edge 13 remains, and a large uncut portion remains at the corner between the upright wall surface Wa and the bottom surface Wb.

  Next, in performing the finishing process on the upright wall surface Wa of the work material W thus roughened, as shown in FIG. 4, the center axis Y of the tool main body 2 to which the cutting insert 10 is attached is set. In a state in which the straight cutting edge 12 provided in the cutting insert 10 is inclined by 40 degrees corresponding to the inclination angle θ1 with respect to the center axis Y with respect to the center axis Y, and the straight cutting edge 12 is along the vertical wall surface Wa to be cut, The tool body 2 is moved along the vertical wall Wa at a pitch pb within the length L of the straight cutting edge 12 while rotating the tool main body 2, and the workpiece W is set up by the straight cutting edge 12 of the cutting insert 10. The wall surface Wa is cut so as to be linear.

  Then, while rotating the tool main body 2 in this manner, the linear cutting edge 12 of the cutting insert 10 is moved along the vertical wall surface Wa at a pitch pb within the length of the linear cutting edge 12 so that the work material W When the vertical wall surface Wa is cut in a straight line, the linear cutting edge 12 of the rotating cutting insert 10 moves while being rotated along the vertical wall surface Wa. The cusp height CH remaining without being cut by the outer peripheral cutting edge 13 is appropriately cut so that a straight and accurate vertical wall surface Wa can be cut, and the uncut portion at the corner between the vertical wall surface Wa and the bottom surface Wb is not cut. The cut portion is also appropriately cut, so that appropriate finishing can be performed.

  Although not shown, even when cutting is performed on the bottom surface Wb of the work material W, it is provided on the cutting insert 10 in the same manner as in the case of the upright wall surface Wa of the work material W. After cutting by the outer peripheral cutting edge 13, the cutting can be performed in a straight line by the straight cutting edge 12 provided on the cutting insert 10.

  In the cutting insert in the cutting edge exchangeable rotary cutting tool disclosed in Patent Document 2, a convex arc-shaped bottom cutting edge and a convex arc-shaped having a larger radius of curvature than the bottom cutting edge connected to the bottom cutting edge. Since the cutting insert 10 of the present application does not include the portion of the straight cutting edge 12, the cutting was performed at a large pitch using the portion of the outer cutting edge as described above. Later, when performing further finishing cutting, it is necessary to perform cutting using an outer peripheral cutting edge having a large radius of curvature. In this case, in order to reduce the cusp height CH, a cutting edge replaceable rotary cutting tool is used. It is necessary to make the pitch at which the cutting insert is sent at a very small pitch for cutting.

  For this reason, in the cutting edge replaceable rotary cutting tool 1 according to the embodiment of the present invention using the cutting insert 10 as described above, when cutting the upright wall surface Wa and the bottom surface Wb of the workpiece W, Patent Document 2 As compared with the blade-replaceable rotary cutting tool shown in (1), these cutting operations can be performed more efficiently while improving the processing accuracy of cutting the upright wall surface Wa and the bottom surface Wb in a straight line.

  In addition, the cutting insert 10 used in the cutting edge replaceable rotary cutting tool 1 according to the present invention is not limited to the one shown in FIGS. 1 (A) and 1 (B), and the center axis Y At the center on the tip side, the bottom cutting edge 11 is formed in a convex arc shape so as to extend on both sides thereof, and each of the bottom cutting edges 11 is linearly extended so as to be tangent to both ends thereof. Each straight cutting edge 12 and a projection having a larger radius of curvature than the bottom cutting edge 11 so as to be continuous with the end of each straight cutting edge 12 and toward the center axis Y from an extension of each straight cutting edge 12. What is necessary is just to provide the outer peripheral cutting edge 13 of an arc shape.

  For example, when a small width vertical wall surface processing or the like is performed on the work material W, as shown in FIG. 5, the center of the tangent line X2 at the center of the outer peripheral cutting edge 13 provided on the cutting insert 10 is formed. By reducing the inclination angle θ2 with respect to the axis Y, it is possible to use the cutting insert 10 having a reduced width.

1: Rotary cutting tool with replaceable cutting edge 2: Tool body 3: Mounting part 4: Mounting screw 10: Cutting insert 11: Bottom cutting edge 12: Straight cutting edge 13: Outer peripheral cutting edge 14: Mounting hole CH: Cusp height R1: Bottom Radius of curvature R2 of the cutting edge: radius of curvature W of the outer peripheral cutting edge W: work material Wa: vertical wall surface Wb of the workpiece: bottom surface X1 of the workpiece: extension line X2 of the straight cutting edge X2: at the center of the outer peripheral cutting edge Tangent line Y: Central axis pa of the tool main body Pa: Pitch during rough machining pb: Pitch for finishing machining θ1: Inclination angle of extension of straight cutting edge with respect to central axis θ2: Incline of tangent at center of outer peripheral cutting edge with respect to central axis angle

Claims (9)

  In the cutting insert detachably attached to the tip of the tool body that rotates around the central axis, as a cutting edge for cutting the work material, a convex arc-shaped bottom cutting edge at the center on the tip side A straight cutting edge that is inclined and tangentially extends to the end of the bottom cutting edge and extends linearly, and is extended from the straight cutting edge so as to be continuous with the end of the straight cutting edge. A cutting insert having a convex arc-shaped outer peripheral cutting edge having a larger radius of curvature than a bottom cutting edge so as to be closer to a center side than a line.   The cutting insert according to claim 1, wherein a connecting portion between the straight cutting edge and the outer peripheral cutting edge is tangent.   3. The cutting insert according to claim 1, wherein a length of the straight cutting edge is in a range of 0.2 to 10 mm.   The cutting insert according to any one of claims 1 to 3, wherein an inclination angle of the straight cutting edge with respect to the center axis is less than 45 degrees.   The cutting insert according to any one of claims 1 to 4, wherein a radius of curvature R1 of the bottom cutting edge is in a range of 0.2 to 10 mm, and a radius of curvature R2 of the outer peripheral cutting edge is A cutting insert having a range of 10 to 1500 mm.   The cutting insert according to any one of claims 1 to 5, wherein the cutting insert has a front-to-back inversion symmetry with respect to the center axis, and each of the cutting edges is a pair. A cutting insert characterized by being provided.   7. A cutting edge exchange type rotary cutting wherein the cutting insert according to any one of claims 1 to 6 is detachably attached to a tip portion of a tool main body which rotates around a central axis. tool.   A straight cutting edge of a cutting edge of a cutting insert mounted on a tip portion of the tool body when cutting a processing surface of a work material using the rotary cutting tool with a replaceable cutting edge according to claim 7. Is set along the machined surface of the work material, the tool body is sent at a pitch within the range of the length of the straight cutting edge, and the machined surface of the work material is straightened. A method of using a cutting edge-changeable rotary cutting tool, which is characterized by performing cutting. When cutting a machined surface of a work material using the cutting edge replaceable rotary cutting tool according to claim 7, the radius of curvature of the cutting edge of the cutting insert of the cutting insert attached to the tip of the tool body is cut. After setting the tool body so that a large outer peripheral cutting edge is along the processing surface of the work material, the outer peripheral cutting edge of the tool body is used to cut the processing surface of the work material in a state close to a straight line, The tool main body is set such that the straight cutting edge of the cutting insert of the cutting insert attached to the tip of the tool main body is along the machined surface of the work material, and the tool main body is set to the straight cutting edge. A method of using a rotary cutting tool with a replaceable cutting edge, wherein the cutting surface is fed in a pitch within a range of a length to cut a processing surface of a work material in a straight line.

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