JP5441615B2 - Cutting insert, cutting tool, and method of manufacturing workpiece - Google Patents

Description

  The present invention relates to a cutting insert, a cutting tool, and a method for manufacturing a workpiece.

  Conventionally, in a cutting insert, a breaker groove is formed inward of a main cutting edge for cutting a work material from the viewpoint of improving chip dischargeability. For example, Patent Document 1 discloses a cutting insert having a breaker groove formed of a rake face and a rising face with respect to a main cutting edge. However, when a cutting insert having such a rising surface is used to cut a difficult-to-cut material, the generated chip is curled by the rising surface, and the tip of the chip is entangled between the cutting edge and the work material. There is. In particular, such a phenomenon is particularly remarkable under conditions where the feed amount is high.

JP-A-8-323510

  The subject of this invention is providing the cutting insert which has the outstanding chip discharge | emission property.

The cutting insert in one embodiment of the present invention includes a main cutting edge located at the intersection of the first side surface and the upper surface, and a sub-cut located at the intersection of the second side surface adjacent to the first side surface and the upper surface. A blade, a wiping blade positioned at the intersection of the third side surface adjacent to the second side surface and the upper surface, and the upper surface, the inner side of the main cutting blade , the auxiliary cutting blade and the wiping blade A rake face located on the inner side of the main cutting edge and the auxiliary cutting edge, and a rake angle α, and a rake face located on the inner side of the first rake face . A second rake face located on the inner side and connected to the first rake face and forming a rake angle β smaller than the rake angle α, and the width of the first rake face is the first rake face The width becomes wider as the distance from the wiping blade adjacent to the sub-cutting blade located on the outer side of the blade increases.

Cutting tool according to an embodiment of the present invention comprises a holder and the cutting insert, the cutting insert is more worn.

  A method of manufacturing a workpiece according to an embodiment of the present invention includes a step of rotating the cutting tool to bring it closer to the work material, and bringing a cutting blade of the cutting tool into contact with the surface of the work material to form the work piece. A step of cutting a material, and a step of separating the cutting tool from the work material.

  According to the cutting insert of the present invention, the rake face has a first rake face that forms a rake angle α and a second rake face that forms a rake angle β that is smaller than the rake angle α, and the first rake face is Since it becomes wide as it leaves | separates from a wiping blade, it is suppressed that the generated chip | curd becomes a curl which goes to the front of a cutting blade, and it passes through a 2nd rake surface and a seating surface from a 1st rake face. Discharged. Therefore, the entanglement of chips between the cutting blade and the work material is reduced, and the chip dischargeability is excellent.

It is a perspective view which shows one Embodiment of the cutting insert of this invention. It is a top view of the cutting insert of FIG. It is a side view of the cutting insert of FIG. (A) And (b) is the AA expanded sectional view of FIG. 2, and the BB expanded sectional view, respectively. It is a perspective view showing one embodiment of a cutting tool of the present invention. It is a principal part enlarged view of the cutting tool of FIG. (A), (b), (c) is a perspective view which each shows embodiment of the cutting method of this invention in order of a process.

<Cutting insert>
Hereinafter, a cutting insert 1 (hereinafter simply referred to as an insert 1) according to an embodiment of the present invention will be described with reference to FIGS.

  In FIG. 1, the insert 1 includes a substantially polygonal plate-like main body. The shape of the main body is not particularly limited as long as it is a shape normally used for inserts by those skilled in the art, for example, a triangle, a quadrangle, a pentagon, a hexagon, and an octagon when viewed from above. In the present embodiment, a substantially pentagonal shape having five long sides is used.

  The insert 1 includes an upper surface 2 that functions as a rake surface, a lower surface 3 that functions as a seating surface, and a side surface 4 that is continuous with the upper surface 2 and the lower surface 3 and functions as a flank surface. A cutting blade 5 is formed at the intersection of the upper surface 2 and the side surface 4. Further, a through-hole 6 for passing a mounting screw is formed from the upper surface 2 toward the lower surface 3. A step portion inside the through hole 6 on the upper surface 2 is a contact portion 7 with which the head of the mounting screw engages. The contact portion 7 is formed vertically so that the insert 1 can be reversed and fixed. Further, on the upper surface 2 of the insert 1, a land portion 8 having a narrow flat surface is formed along the cutting edge 5, and a rake face (inclined surface) 9 corresponding to the cutting edge 5 is formed.

  The insert 1 shown in FIG. 1 has a side surface 4 formed perpendicular to the upper surface 2 and the lower surface 3 (see FIG. 3). That is, the insert 1 is a negative cutting insert that can use both the upper surface 2 and the lower surface 3 as rake surfaces. Therefore, this insert 1 can use 10 corners for cutting on five sides on one side and upper and lower sides. In this case, the cutting edge 5 is also formed at the intersecting ridge line part of the lower surface 3 and the side surface 4, and when the lower cutting edge 5 is used, the lower surface 3 is used as a rake surface, and the upper surface 2 is used as a seating surface. Is possible. The cutting blade 5 may not be formed on the lower surface side. Even in that case, five corners can be used for cutting. Moreover, in the cutting insert of this invention, what is called a positive type cutting insert with which the clearance angle was provided to the side surface 4 may be sufficient.

  As shown in FIG. 1, specifically, the cutting edge 5 is formed at the intersection between the first side surface 41 and the upper surface 2, and at the intersection between the second side surface 43 and the upper surface 2. The auxiliary cutting edge 53 and the wiping edge 52 formed at the intersection of the third side surface 42 and the upper surface 2. In the present embodiment, the first side surface 41, the second side surface 43, and the third side surface 42 are adjacent to each other through the corner surfaces 44, 45, and the main cutting edge 51, the auxiliary cutting edge 53, and the wiping edge 52 are the corners. They are connected via cutting edges 54 and 55. On the opposite side of the third side surface 42, the next first side surface 41 continues through a corner surface 46. An upper end of the corner surface 46 is a corner cutting edge 56.

  The main cutting edge 51 is a blade that plays a main role in generating chips in the cutting action. The main cutting edge 51 is formed longer than the other cutting edges, that is, the wiping edge 52 and the auxiliary cutting edge 53. And the main cutting edge 51 is made into the loose curve line which becomes convex upwards so that FIG. 3 may show. In this embodiment, a vertex P, which will be described later, is closer to the auxiliary cutting edge 53 side of the main cutting edge 51. That is, in this embodiment, since the apex P is provided in the middle of the main cutting edge 51, the vicinity of the end of the main cutting edge 51 on the side of the auxiliary cutting edge 53 is inclined so as to approach the upper surface as the distance from the auxiliary cutting edge 53 increases. To the apex P. And after that, it inclines so that it may approach a lower surface as it leaves | separates from the sub cutting blade 53. FIG.

  The wiping blade 52 is formed for the purpose of improving the finished surface accuracy of the work material. The wiping blade 52 is substantially linear when viewed from above (see FIG. 2), and is inclined so as to be separated from the lower surface as the auxiliary cutting edge 53 is approached when viewed from the side. In this embodiment, the inclination is steeper than the inclination near the end of the main cutting edge 51.

  The above-mentioned secondary cutting edge 53 is a cutting edge having an outer peripheral cutting edge angle larger than that of the main cutting edge 51. For example, a main cutting such as reducing cutting resistance of the main cutting edge 51 or suppressing damage to the main cutting edge. It is provided for the purpose of assisting cutting with the blade 51. “Outer peripheral cutting edge angle” refers to the inclination angle of the cutting edge with respect to the rotation center axis of the holder when the insert is attached to the holder. For example, in the cutting tool 20 of FIG. 6, the angle θ1 formed by the main cutting edge 51 and the line L parallel to the rotation center of the holder 10 (see S in FIG. 5) is the outer peripheral cutting edge angle of the main cutting edge 51. . Similarly, the angle θ2 formed by the line L and the secondary cutting edge 53 is the outer peripheral cutting edge angle of the secondary cutting edge 53. The outer peripheral cutting edge angle of the main cutting edge 51 is set at, for example, about 0 to 60 degrees, and the outer peripheral cutting edge angle of the auxiliary cutting edge 53b is set at a larger angle, for example, about 60 to 80 degrees. Further, in consideration of damage / deletion of the cutting edge, the outer peripheral cutting edge angle of the auxiliary cutting edge 53 is set to be larger than the outer peripheral cutting edge angle of the main cutting edge 51. Specifically, it is preferable that the outer peripheral cutting edge angle of the sub cutting edge 53 is set to 1.2 times the outer peripheral cutting edge angle of the main cutting edge 51, preferably 1.5 times or more. . The auxiliary cutting edge 53 may be between the main cutting edge 51 and the wiping edge 52, and a plurality of auxiliary cutting edges may be provided between them.

  As shown in FIG. 3, the auxiliary cutting edge 53 is provided so as to connect the wiping edge 52 and the main cutting edge 51, and in this embodiment, is inclined so as to be separated from the lower surface 3 toward the main cutting edge 51. .

  The entire upper cutting edge 5 including the wiping edge 52, the auxiliary cutting edge 53, and the main cutting edge 51 is a gently curved line that protrudes upward as shown in FIG. The entire cutting edge 5 is lowest at the vicinity of the boundary between the third corner cutting edge 56 and the wiping edge 52 (see point V), and from there, the wiping edge 52 in the circumferential direction (counterclockwise in FIG. 2). The second corner cutting edge 55, the secondary cutting edge 53, the first corner cutting edge 54, and the main cutting edge 51 are gradually raised. Then, it becomes the highest at the above-mentioned vertex P, and further descends from the vertex P in the circumferential direction, and gradually descends, again in the vicinity of the boundary between the next third corner cutting edge 56 and the next sweeping edge 52. The lowest.

  The lower cutting edge 5 has a shape obtained by inverting the upper cutting edge 5 so that the cutting insert 1 can be used with the cutting insert 1 turned upside down. That is, it is rotationally symmetric about a line perpendicular to the paper surface of FIG. In this case, as shown on the right side of FIG. 3, the main cutting edge 51 is formed at the lower end of the first side face 41, but the sub cutting edge 53 is formed at the lower end of the third side face 42 instead of the countersink. . Similarly, a wiping blade 52 is formed at the lower end of the second side surface 43 instead of the auxiliary cutting blade. Corner cutting blades 56, 55, 54 are formed between the cutting blades 51, 52, 53. Therefore, it is preferable that the length of the third side surface 42 and the length of the second side surface 43 are substantially the same length. Similarly, it is preferable that the length of the corner surface 46 that is continuous to the left side of the first side surface 41 and the length of the corner surface 46 that is continuous to the opposite side are substantially the same.

  The lengths of the main cutting edge 51, the wiping edge 52, and the auxiliary cutting edge 53 are not particularly limited except for the above points. For example, the ratio of the length of the main cutting edge 51 and the sub cutting edge 53 is set to 2: 1 to 10: 1, preferably about 2: 1 to 6: 1. The lengths of the wiping blade 52 and the sub-cutting blade 53 are not particularly limited, but when they are used upside down, the length ratio is approximately 1: 1. When a negative type insert is designed, or when a positive type is not assumed to be reversed, the length ratio can be set relatively freely, such as 1: 1 to 1: 6.

  As shown in FIG. 2, the corner cutting edges 54, 55, 56 are curved when viewed from above. The radius of curvature of these corner cutting edges is not particularly limited. For example, the length and curvature radius of the first corner cutting edge 54 and the third corner cutting edge 56 are substantially the same, and the second corner cutting edge 55 is sandwiched between the wiping edge 52 and the auxiliary cutting edge 53. It is so gentle. With such a configuration, a significant variation in the thickness between chips generated by the main cutting edge 51 and the sub cutting edge 53 is suppressed, and the shape of the chips can be controlled.

  For example, when the secondary cutting edge 53 and the main cutting edge 51 are continuous by the corner cutting edge 54, the load applied to the boundary between the secondary cutting edge and the main cutting edge is dispersed during cutting, so that defects at the boundary are suppressed. can do. Moreover, chips can be released smoothly.

  As described above, the land portion 8 refers to a narrow region between the respective cutting blades 51, 52, 53 and the rake face 9 corresponding to them. The width of the land portion 8 is appropriately set mainly from the viewpoint of the strength of the corresponding cutting edges 51 to 56. Usually, the width of the land portion 8 is set to be substantially constant.

  The rake face 9 is located on the inner side of the main cutting edge 51 and the auxiliary cutting edge 53. The rake face 9 may be formed along the entire cutting edge 5 as in the present embodiment. The rake face 9 further has a first rake face 91 corresponding to the main cutting edge 51 and the auxiliary cutting edge 53 and a second rake face 92 connected to the first rake face 91. The rake angle of the first rake face 91 is set to be larger than the rake angle of the second rake face 92. Here, the rake angle means an angle formed by a surface parallel to the lower surface 3 (sitting surface) and the rake surface. Specifically, as shown in FIG. 4A, the rake angle of the first rake face is expressed as a rake angle α, and the second rake face is expressed as a rake angle β. The ranges of the rake angle α and the rake angle β are not particularly limited, but are preferably 5 ° <α and β <30 ° from the viewpoint of good chip dischargeability, and 10 ° <α and β <25 °. More preferably.

  The rake angle α and the rake angle β may be constant or may change (gradual change). When the rake angle α is set so as to increase as it moves away from the wiping blade, the cutting resistance can be reduced. In addition, when the rake angle β is increased as the distance from the wiping blade increases, the chips become spiral and the chip dischargeability can be improved.

  In the present embodiment, as shown in FIGS. 4A and 4B, the rake angle α is set to be larger than the rake angle β in a cross section perpendicular to the cutting edge. Specifically, the difference between the rake angle α and the rake angle β is set to exceed 3 °. With such a configuration, the generated chips smoothly pass through the first rake face and the second rake face, and are gently curled to improve chip discharge performance.

  Further, in the present embodiment, the maximum value αMax of the rake angle α of the first rake face 91 and the minimum value βMin of the rake angle β of the second rake face 92 are set to be larger than 10 °. With such a configuration, cutting resistance can be reduced.

  The width of the first rake face 91 (the length in the direction perpendicular to the main cutting edge 51 or the sub cutting edge 53) is formed so as to become wider as the distance from the wiping edge 52 increases. In this way, the first rake face becomes wider as it moves away from the auxiliary cutting edge 52, so that the generated chips are smoothly discharged from the first rake face to the second rake face. In the present embodiment, the width of the first rake face 91 is formed so as to increase at a constant rate as the distance from the auxiliary cutting edge 52 increases. Furthermore, in this embodiment, the rake face 9 is formed so that the width (the length in the direction perpendicular to the main cutting edge 51) is substantially constant. That is, the second rake face 92 is formed such that the length in the direction perpendicular to the main cutting edge 51 becomes shorter as the distance from the sub cutting edge increases. With such a configuration, a large area of the flat surface 2 (surface that functions as a seating surface) can be secured.

  The first rake face and the second rake face may be flat or curved. Further, the planar first rake face and the planar second rake face may be connected via a curved intermediate rake face.

  In the present embodiment, the inner flat surface 2 (functioning as a seating surface) is positioned at a lower position than the rake face 9 in a sectional view. The flat surface 2 is connected to the rake face 9 through a wall surface substantially parallel to the first side surface. With such a configuration, the area of the seating surface is ensured, and the stability of the tip is improved during cutting.

<Cutting tools>
The cutting tool 20 shown in FIGS. 5 and 6 is obtained by attaching the above-described insert 1 to a known holder 10. A plurality of chip pockets 13 are formed at the outer peripheral tip of the holder 10 at intervals in the circumferential direction. The chip pocket 13 is a portion cut out in a substantially V shape in plan view, and the insert 1 is attached to each of a plurality of attachment surfaces 14 formed thereby. The insert 1 is mounted with the main cutting edge 51 protruding from the outer periphery of the holder 10 with the upper surface 2 facing the front side in the rotational direction indicated by the arrow A. By cutting the cutting tool 20 around the rotation center S in the direction of arrow A, cutting is performed by the main cutting edge 51, the auxiliary cutting edge 53, and the wiping edge 52.

<Cutting method>
Next, with reference to FIGS. 7 a to 7 c, a procedure for cutting a work material using a cutting tool (a rolling tool) 20 will be described. Prior to starting the cutting, the insert 1 is mounted on the holder 10 as shown in FIG. At this time, the insert 1 is attached along the same circumference of the holder 10. As an attachment method, for example, a bolt is inserted into the through hole 6 of the insert 1, and the bolt is screwed into a female screw formed on the attachment surface 14 of the holder 10. Alternatively, a bolt is passed through the through hole formed in the holder 10 and tightened with a nut from the opposite side. In this embodiment, the rotation center S of the cutting tool 11 is arranged at a substantially right angle to the surface of the work material 100 shown in FIG. At that time, the main cutting edge 51 is inclined at an angle of about 45 degrees with respect to the work material 100.

  Next, as shown in FIG. 7a, the work material 100 is fixed to a milling machine bed or the like, and the holder 10 is moved in the direction of arrow B to set an appropriate cutting amount. Next, as shown in FIG. 7 b, the holder 10 is moved in the direction of arrow C while rotating around the rotation center S in the direction of arrow A. Thereby, the main cutting edge 51 and the sub cutting edge 53 contact | abut with the circular-arc-shaped part ahead of a feed direction, and cut the part according to the cutting amount. At that time, since the plurality of inserts 1 sequentially enter the cutting region and perform cutting, arc-shaped streaks (cutting marks) remain on the surface 16. However, since the wiping blade 52 cuts the arc-shaped streaks remaining on the surface 16 of the work material 100, the surface 16 becomes smooth. As can be seen from FIG. 6, only the portion (lower portion) of the main cutting edge 51 that is actually close to the sub cutting edge 53 is cut into the workpiece 100 with a predetermined cutting amount K.

  Then, as shown in FIG. 7 c, after the cutting tool 20 has passed through the work material 100, the cutting tool 20 is pulled up in the direction of arrow D, and the cutting tool 20 is separated from the work material 100. In the case of continuing the cutting process, the cutting tool 20 is kept rotated and brought into contact with the same or different part of the workpiece 100, and the above-described cutting process may be repeated. When the cutting blade used is worn, the insert 1 is rotated around the central axis of the hole (reference numeral 6 in FIG. 1), or the upper and lower surfaces are turned over, and an unused cutting blade is used.

  In the above-described cutting method, each insert 1 hits the work material 100, cuts, and then separates from the work material 100 in order.

  In the embodiment, the cutting tool is sent while being rotated. However, the cutting tool can be rotated to feed the work material. Further, a cutting tool that does not rotate, such as a lathe, can be brought into contact with the rotating work material for cutting. As a processing machine, it can be used by attaching to holders and chucks of various processing machines such as face mills, end mills, milling, and drills.

DESCRIPTION OF SYMBOLS 1 Cutting insert 2 Upper surface 3 Lower surface 4 Side surface 41 1st side surface 42 3rd side surface 43 2nd side surface 44, 45, 46 Corner surface 5 Cutting blade 51 Main cutting blade 52 Fraying blade 53 Sub cutting blade 54, 55, 56 Corner cutting blade P apex θ1 outer peripheral cutting edge angle of main cutting edge θ2 outer peripheral cutting edge angle of secondary cutting edge 6 through hole 7 abutting portion 8 land portion 9 rake face 91 first rake face 92 second rake face 10 holder 20 cutting tool 30 cutting Tool 31 Holder 100 Work material

Claims (15)

A main cutting edge located at the intersection of the first side surface and the upper surface;
A sub cutting edge located at the intersection of the second side surface adjacent to the first side surface and the upper surface;
A wiping blade located at the intersection of the third side surface adjacent to the second side surface and the upper surface;
A rake face located on the inner side of the upper cutting edge , the main cutting edge , the auxiliary cutting edge and the wiping edge ,
The rake face, the main cutting edge and located on the inner side of the minor cutting edge, a first rake surface forming a rake angle alpha, the first located on the inner side of the first rake face A second rake face connected to the rake face and forming a rake angle β smaller than the rake angle α,
The cutting insert in which the width of the first rake face increases as the distance from the wiping edge adjacent to the sub-cutting edge located outside the first rake face increases. 2. The cutting insert according to claim 1, wherein a width of the second rake face decreases as the distance from the wiping edge adjacent to the sub-cutting edge located outside the second rake face increases.   The cutting insert according to claim 1 or 2, wherein each of the first rake face and the second rake face is planar.   The cutting insert according to claim 3, wherein the first rake face is connected to the second rake face via a curved intermediate rake face.   The cutting insert according to claim 1 or 2, wherein each of the first rake face and the second rake face is curved.   The cutting according to any one of claims 1 to 5, wherein a difference between the rake angle α and the rake angle β is larger than 3 ° in a cross-sectional view perpendicular to the main cutting edge or the auxiliary cutting edge. insert. 7. The cutting insert according to claim 1, wherein the rake angle α increases as the rake angle α increases away from the wiping blade adjacent to the sub-cutting blade located outside the first rake face . The cutting insert according to any one of claims 1 to 7, wherein the rake angle β increases as the rake angle β moves away from the wiping blade adjacent to the sub-cutting blade located outside the second rake face .   The cutting insert according to any one of claims 1 to 8, wherein a width of the rake face is substantially constant from the sub cutting edge to the main cutting edge.   The cutting insert according to claim 1, wherein a flat surface is provided on an inner side of the rake face, and the flat face is located at a position lower than the rake face in a sectional view.   The cutting insert according to claim 10, wherein the flat surface is connected to the rake surface through a wall surface substantially parallel to the first side surface.   The cutting insert according to claim 1, further comprising a land located between the main cutting edge and the rake face. Comprising a cutting insert according to any one of claims 1 to 12, and a holder to which the cutting insert is more worn, the cutting tool.   The cutting tool according to claim 13, wherein the cutting insert is mounted on the holder such that the main cutting edge and the auxiliary cutting edge have a positive axial rake with respect to the rotation center axis of the holder. A step of rotating the cutting tool according to claim 13 or 14 to approach the work material;
A step of cutting the work material wherein contacting the cutting edge of the cutting tool on the surface of the workpiece,
Separating the cutting tool from the work material;
A method for manufacturing a work piece, comprising:

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