Tool body and cutting tool including same

Abstract

To provide an inexpensive and lightweight tool body and a cutting tool including the same, which can achieve two contradictory features of overcoming the deterioration of workpiece machining accuracy when members are attached to each other while retaining the advantages of additive manufacturing. [Solution] The tool body (10) of the cutting tool (1) includes a mounting seat (21) for a cutting insert (70) provided on the tip end (10t) side along a central axis (10X), and a cylindrical portion (30) provided on the base end (10b) side opposite the tip end (10t) along the central axis (10X). The surface roughness of the mounting seat (21) is smaller than the surface roughness of the circumferential surface (31) of the cylindrical portion (30).

Description

[Technical Field]

[0001] The present invention relates to a tool body and a cutting tool including the same. [Background technology]

[0002] Internal diameter machining, which processes the inner diameter of holes or cylindrical shapes inside parts or materials, is performed to improve the dimensional accuracy and surface finish of the inside, and ultimately the functionality and assembly accuracy of the part. Tools used in such internal diameter machining include exchangeable-head tools, which allow only the head to be replaced to suit the desired machining mode. An exchangeable-head tool has the advantage of requiring less replacement time than replacing the shank itself (see, for example, Patent Document 1). Given this feature, it is assumed that multiple types of heads are prepared in advance and reused depending on the machining mode, so it is desirable for each of these heads to be as inexpensive as possible.

[0003] Now, when considering the case of using such a tool for internal machining, the tool tends to have a long protrusion length, which makes it easy for chatter due to resonance to occur. To suppress this chatter, it is desirable to reduce the weight of the head located at the tip of the tool. Regarding this point, for example, Patent Documents 2 and 3 disclose examples of weight reduction achieved by machining grooves in the head portion through cutting. However, achieving weight reduction through cutting increases the processing cost, which may be contrary to the aforementioned goal of low cost.

[0004] One technology that can address all of these issues is additive manufacturing, which offers a high degree of design freedom. For example, Patent Document 3 discloses an example of the use of additive manufacturing in an integrated tool, specifically, a technology that uses additive manufacturing to create a hollow shape in the head section, thereby reducing the tool weight without requiring cutting. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2020-533188 [Patent Document 2] Japanese Patent Application Laid-Open No. 2001-105204 [Patent Document 3] Japanese Patent Publication No. 2023-062344 Summary of the Invention [Problem to be solved by the invention]

[0006] However, since products manufactured by additive manufacturing generally tend to have rough surfaces, there is a concern that if the above-mentioned conventional technology is applied directly to a head-exchangeable tool, it may lead to a deterioration in the machining accuracy of the workpiece (material to be cut) when the head is attached to the shank, etc.

[0007] Therefore, the present invention aims to provide an inexpensive and lightweight tool body and a cutting tool including the same, which can achieve the contradictory characteristics of overcoming the deterioration in workpiece processing accuracy when attaching components to each other while retaining the advantages of additive manufacturing. [Means for solving the problem]

[0008] One aspect of the present invention is a tool body for a cutting tool, comprising: a mounting seat for a cutting insert provided on the tip end side along the central axis; a cylindrical portion provided on a base end side opposite to the tip end portion along the central axis; Equipped with The tool body has a surface roughness of the mounting seat that is smaller than the surface roughness of the circumferential surface of the cylindrical portion.

[0009] According to the tool body of this aspect, the surface roughness of the attachment area (in this aspect, the pocket seat) of the other component (in this aspect, the cutting insert) is reduced by, for example, cutting processing to improve attachment accuracy, while the other parts are left as they are during additive manufacturing. This makes it possible to overcome the deterioration in accuracy when attaching components while retaining the advantages of additive manufacturing. Moreover, the additively manufactured tool body is inexpensive and lightweight.

[0010] The tool body as described above may include a first plane adjacent to a wall surface rising from the bottom surface of the mounting seat and forming a ridge between the first plane and the wall surface, and a second plane adjacent to the first plane, parallel to the first plane, lower than the first plane and higher than the bottom surface, and the surface roughness of the first plane may be equal to the surface roughness of the mounting seat and smaller than the surface roughness of the second plane.

[0011] The tool body as described above may further include a third plane adjacent to the first plane and inclined at a certain angle relative to the first plane, and the surface roughness of the third plane may be equivalent to the surface roughness of the first plane.

[0012] The tool body as described above may have a cylindrical portion provided with a cylindrical upper flat surface formed by cutting out a part of the circumferential surface of the cylindrical portion, and the surface roughness of the cylindrical upper flat surface may be smaller than the surface roughness of the circumferential surface.

[0013] The tool body as described above may comprise a cylindrical bottom flat surface provided on the opposite side of the cylindrical top flat surface, and a cylindrical side flat surface provided on the side of the peripheral surface, and the surface roughness of these cylindrical bottom flat surface and cylindrical side flat surface may be equivalent to the surface roughness of the peripheral surface.

[0014] The tool body as described above may have an interchangeable head that is detachable from the shank.

[0015] The tool body as described above may include a plurality of through holes penetrating the cylindrical portion from a base end face facing the base end side of the cylindrical portion toward the tip end side, countersunk holes around the through holes, at least one rib having a shape connected to any of the countersunk holes, and at least one lightening recess having a shape connected to any of the countersunk holes.

[0016] In the tool body as described above, the recessed portion may have a shape in which the depth of the recessed portion increases toward the tip end portion.

[0017] In the tool body as described above, the rib may be provided in a shape that connects at least one of the plurality of counterbores and any one of the first to third flat surfaces.

[0018] In the tool body as described above, at least one of the plurality of through holes may be an elongated hole.

[0019] In the tool body as described above, at least one of the plurality of counterbores may have a shape in which a part thereof opens onto the circumferential surface of the cylindrical portion.

[0020] In the tool body as described above, the base end surface of the cylindrical portion facing the base end side may be formed of a sawtooth portion, and the surface roughness of the sawtooth portion may be smaller than the surface roughness of the circumferential surface of the cylindrical portion.

[0021] The tool body as described above may have a head joined to a shank, with the cylindrical portion disposed on the head.

[0022] Another aspect of the present invention is a cutting tool including a tool body as described above. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a perspective view showing an example of the structure around a head of a cutting tool with an exchangeable head according to an embodiment of the present invention. FIG. [Figure 2] FIG. 10 is a perspective view of the head and its surroundings of the replaceable head cutting tool, viewed from a different angle. [Figure 3] FIG. 2 is an exploded perspective view showing an example of the structure around the head of the head-exchangeable cutting tool. [Figure 4] FIG. 10 is an exploded perspective view of the head and its surroundings of the replaceable head cutting tool, viewed from a different angle. [Figure 5] FIG. 10 is an exploded perspective view of the head and its surroundings of the replaceable head cutting tool, viewed from yet another angle. [Figure 6] FIG. 2 is an enlarged perspective view showing the periphery of a head of the replaceable head cutting tool. [Figure 7] FIG. 2 is a perspective view showing an example of the structure of a head of a head-exchangeable cutting tool. [Figure 8] FIG. 2 is a perspective view of the head as seen from its base end side. [Figure 9] FIG. 2 is a perspective view of the head as seen from the side where the cylindrical bottom flat surface is located. [Figure 10] FIG. 2 is a front view of the head as seen from the tip end side along the central axis. [Figure 11] FIG. 10 is a diagram showing the head and the like of a cutting tool during pre-turning. [Figure 12] FIG. 10 is a diagram showing the head of a cutting tool when the inner diameter of a workpiece is post-machined. DETAILED DESCRIPTION OF THE INVENTION

[0024] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a tool body and a cutting tool including the same according to the present invention will be described in detail below with reference to the drawings (see FIG. 1, etc.).

[0025] The cutting tool of this embodiment is a head-exchangeable cutting tool 1. The head-exchangeable cutting tool 1 is configured as a tool that cuts into a workpiece (material to be cut) 100 by feeding the cutting edge 71 of the cutting insert 70 during machining on an automatic lathe (not shown) or the like (see FIGS. 11 and 12). The head-exchangeable cutting tool 10 of this embodiment used for such turning is a head-exchangeable cutting tool in which the head 10 can be attached and detached to and from the shank 80, and includes the shank 80, the head 10, and a head fixing screw (fixing member) 50 for fixing the head 10 to the shank 80 (see FIGS. 1 to 6, etc.). Note that in this specification, the term "tool body" is used to refer to the portion of the cutting tool excluding the cutting insert or the portion that constitutes the same (for example, the head 10 described above).

[0026] [shank] The shank 80 has a generally cylindrical shape with a pair of grippable surfaces 82A consisting of parallel flat surfaces above and below a peripheral surface 81 (see FIG. 1, etc.). A flat surface 82B may be provided on the side of the peripheral surface 81. The shank 80 of this embodiment has a shape that extends in the longitudinal direction along a central axis 80X (see FIG. 5) that passes through the center of a grippable portion 83 on which the grippable surface 82A is provided, and a head attachment surface 84 is provided at a tip end 80t (the side on which the head 10 is attached or detached) (see FIG. 3, etc.).

[0027] The head mounting surface 84 is provided with a coolant outlet 86 and head fixing screw holes 87 (see FIGS. 3 and 5). The coolant outlet 86 is an opening at the end of a coolant flow path 85 provided inside the shank 80, and is provided, for example, in approximately the center of the head mounting surface 84, from which coolant is supplied to the head 10. The head fixing screw holes 87 are threaded holes with female threads into which the head fixing screws 50 are threaded, and for example, four of them are arranged at equal intervals around the circumference (see FIGS. 3 and 5).

[0028] [head] The head 10 is an exchangeable head that can be attached to and detached from the head mounting surface 84 of the shank 80. The head 10 of this embodiment has a shape designed on the premise that it will be manufactured by additive manufacturing, which has a high degree of design freedom, for example, a shape that has a cylindrical portion 30, which is the portion of the shank 80 on the head mounting surface 84 side, on the base end portion 10b side, and a portion other than the cylindrical portion 30 (hereinafter referred to as the "head front portion" and indicated by reference numeral 20 in the drawings) on the tip end portion 10t side (see FIGS. 3, 7, etc.).

[0029] The cylindrical portion 30 is a generally cylindrical or disk-shaped portion having a peripheral surface 31 with a diameter substantially equal to that of the peripheral surface 81 of the shank 80. The peripheral surface 31 of the cylindrical portion 30 is provided with a cylindrical upper flat surface 32, a cylindrical bottom flat surface 33, and a cylindrical side flat surface 34. The cylindrical upper flat surface 32 is provided on the upper portion of the peripheral surface 31 of the cylindrical portion 30 (see FIG. 7, etc.). The "upper portion" here refers to the portion facing upward in FIG. 10, or in other words, the portion vertically above the gripped surface 82A that is on the upper side when the head 10 is attached to the shank 80 (see FIG. 3, etc.). The cylindrical bottom flat surface 33 is provided on the bottom, opposite the cylindrical upper flat surface 32 (see FIG. 9). The cylindrical side flat surface 34 is provided on only one of the two side portions of the peripheral surface 31 of the cylindrical portion 30 (see FIGS. 9 and 10). The cylinder top flat surface 32 and the cylinder side flat surface 34 are formed by cutting out a portion of the circumferential surface 31. The cylinder bottom flat surface 33 is formed by a flat surface that continues from a portion of the circumferential surface 31 to the bottom surface of the head front part 20 (see FIG. 9).

[0030] The surface roughness of the circumferential surface 31 of the cylindrical portion 30, excluding the upper flat surface 32, and the lower flat surface 33 and side flat surfaces 34 of the cylindrical portion 30, is the roughness of the molding surface, i.e., the surface roughness in the state as it is after additive manufacturing. In contrast, the upper flat surface 32 of the cylindrical portion 30 has a smaller surface roughness than the circumferential surface 31, etc., for example, because a portion of the surface is cut after additive manufacturing, or because that portion of the circumferential surface 81 is cut and shaped after additive manufacturing. The fact that the surface roughness of the upper flat surface 32 of the cylindrical portion 30 is smaller than that of the other portions is advantageous in that it can improve the accuracy of phase determination when a height gauge is applied to the upper flat surface 32 of the cylindrical portion 30 to determine phase. In this embodiment, the surface roughness of the portions suitable for improving processing accuracy or measurement accuracy is reduced and the surface is made finer by, for example, cutting the surfaces, thereby enabling appropriate improvement of accuracy while retaining the advantages of additive manufacturing (low cost, lightweight, simple manufacturing, etc.). From this point of view, the surface roughness of the cylinder bottom flat surface 33 and the cylinder side flat surface 34 may remain the same as the surface roughness of the peripheral surface 31 (as the molding surface).

[0031] Note that the term "surface texture" is similar to the term "surface roughness" (sometimes called surface roughness) used in this specification. Regarding the term "surface texture," one document explains that it refers to the state of minute irregularities, undulations, streaks, and other features found on the surface of a product, and that it is quantified and evaluated using the index "surface roughness." While it may be possible to use the term "surface texture" in light of the content of this explanation, this specification will use the narrower definition of "surface roughness." However, in light of the content of this explanation and the gist of the present invention, there is no problem in using the term "surface texture" instead of "surface roughness." Incidentally, surface roughness is expressed using an index such as the arithmetic mean roughness (Ra) of a cross-sectional curve.

[0032] The base end surface 35 of the cylindrical portion 30, which faces the base end 10b, is the surface that is attached to the head mounting surface 84 of the shank 80. A coolant inlet 46 is provided in the approximate center of the base end surface 35 so as to communicate with a coolant outlet 86 of the head mounting surface 84 (see FIGS. 3 and 4). A cylindrical connecting member 47 may be disposed between the coolant outlet 86 and the coolant inlet 46. In this embodiment, both the base end surface 35 and both sides of the head mounting surface 84 of the shank 80 are serrated (indicated by the symbol S in the figures) to form a sawtooth shape that meshes with each other (see FIGS. 3 and 4, etc.). In this embodiment, both the sawtooth-shaped base end surface 35 and both sides of the head mounting surface 84 of the shank 80 are cut surfaces, and the surface roughness is made smaller than that of the circumferential surface 31, for example, to improve the positional accuracy when the head 10 is attached to the shank 80 (see FIGS. 1 and 2). The serrations S are merely one example of the shape of both the base end surface 35 and the head mounting surface 84 of the shank 80. Although not specifically shown, the base end surface 35 and both the head mounting surface 84 of the shank 80 may have a shape other than serrations, such as a shape provided with keyways.

[0033] A mounting seat 21 for a cutting insert 70 is provided in the head front portion 20 (a portion other than the cylindrical portion 30) of the head 10 (see FIGS. 5, 6, etc.). The mounting seat 21 has a bottom surface 22 and a wall surface 23. The bottom surface 22 is a surface on which the cutting insert 70 is directly or indirectly placed and serves as a positional reference for the height (i.e., the position in the upward direction) of the cutting edge 71. The wall surface 23 is a surface that directly or indirectly continues in the height direction from the bottom surface 22. The mounting seat 21 of the head 10 of this embodiment is designed so that the cutting insert 70 can be placed not only directly but also via a shim 61 (see FIGS. 3 to 5). Therefore, the head 10 has a structure in which a wall surface 22w that abuts against at least a portion of the side surface of the shim 61 and a second bottom surface 22b that abuts against a portion of the bottom surface of the cutting insert 70 are provided between the bottom surface 22 and the wall surface 23 (see FIG. 7, etc.). Wall surface 22w is formed of, for example, a wavy surface that continues substantially perpendicular to bottom surface 22. Second bottom surface 22b is formed of a surface that continues to wall surface 22w and is substantially horizontal to bottom surface 22. Wall surface 23 is provided so as to continue substantially perpendicular to second bottom surface 22b (see FIG. 7, etc.). Bottom surface 22 is provided with shim fixing screw holes 24 into which shim fixing screws 62 for fixing shim 61 are threadedly engaged (see FIGS. 7 and 8). Mounting seat 21 of this embodiment, which has such a shape, is subjected to cutting processing after additive manufacturing, and therefore its surface roughness (in the case of this embodiment, at least both the surface roughness of bottom surface 22 and the surface roughness of wall surfaces 23 that constitute mounting seat 21) is smaller than the surface roughness of peripheral surface 31 of cylindrical portion 30.

[0034] The head front portion 20 of the head 10 further includes a first flat surface 11, a second flat surface 12, and a third flat surface 13 (see FIGS. 7 and 8, etc.). The first flat surface 11 is adjacent to the wall surface 23, forms a ridgeline 15 between the wall surface 23, and is substantially parallel to the bottom surface 21 (see FIG. 7, etc.). In this embodiment, the first flat surface 11 is cut after additive manufacturing, so that its surface roughness is equivalent to that of the mounting seat 21. In the head 10 of this embodiment, both the first flat surface 11 and the wall surface 23 are cut so that their surface roughness is smaller than that of the molded surface. This allows for high positional accuracy of the ridgeline 15 formed therebetween. The ridgeline 15 and its surroundings abut against a portion of the cutting insert 70 and function as a portion that determines the restraining position of the cutting insert 70. Therefore, the head 10 of this embodiment, which has high positional accuracy of the ridgeline 15, also provides high positioning accuracy for the restraining position of the cutting insert 70.

[0035] The first flat surface 11 is provided with a clamp recess 11C into which a portion of the leg 60L of the clamp member 60 is inserted (see FIG. 5, etc.). A clamp fixing screw hole 11H through which a clamp fixing screw 63 passes is provided on the side of the first flat surface 11. The clamp fixing screw hole 11H is inclined with respect to the central axis of the leg 60L of the clamp member 60, so that the tip of the clamp fixing screw 63 can come into contact with a pressed surface 60P formed at an angle with respect to the leg 60L and press the pressed surface 60P (see FIG. 5, etc.).

[0036] The second plane 12 is a surface that is located close to the first plane 11 and closer to the base end 11b than the first plane 11, parallel to the first plane 11, lower than the first plane 11, and higher than the bottom surface 22 (see Figures 7, 8, etc.). This second plane 12 is not subjected to surface processing such as cutting after additive manufacturing, and the surface roughness remains the same as that of the molding surface.

[0037] The third plane 13 is a plane that is close to the first plane 11 and is inclined at a certain angle relative to the first plane 11. In the head 10 of this embodiment, the third plane 13 is provided at a position where it abuts against a clamp inclined surface 60S of the clamp member 60 (see FIGS. 5, 8, etc.). The clamp member 60 presses and clamps the cutting insert 70 (and the shim 61 in this embodiment) by screwing in the clamp fixing screw 63 with the clamp inclined surface 60S abutting against the third plane 13. In this embodiment, the surface roughness of the third plane 13 is made approximately the same as that of the first plane 11 by further surface-treating the molded surface after additive manufacturing, such as by further cutting the molded surface. In this way, in the head 10 in which the surface roughness of the third plane 13 is processed to be smaller than the surface roughness of the modeling skin, the positioning accuracy of the clamping member 60 when the clamping inclined surface 60S is brought into contact with the third plane 13, or the accuracy of the restraining position of the cutting insert 70 or the like by the clamping member 60, is high. Note that the inclination angle of the third plane 13 with respect to the first plane 11 is preferably about 45°, for example, but this is merely a preferred example.

[0038] The cylindrical portion 30 is also provided with a through hole 40 and a counterbore 41. The through hole 40 is a hole that penetrates the cylindrical portion 30 from the surface on the tip end 10t side to the base end surface 35, and multiple, for example, three, through holes 40 are provided (see FIG. 4, etc.). Corresponding to these through holes 40, multiple head fixing screw holes 87 are arranged in the head mounting surface 84 of the shank 80 so as to be parallel to the central axis 80X (see FIG. 3, etc.). These through holes 40 may all be circular, but may also have a different shape. In the head 10 of this embodiment, of the three through holes 40, the through hole (indicated by reference symbol 40L) closest to the second plane 12 is an elongated hole (see FIGS. 3, 10, etc.). In a front view of the head 10 from the tip end 10t side along the central axis 10X, if the first plane 11 overlaps part of the through hole 40L, the head fixing screw 50 may interfere with the clamp member 60 when being fastened, making it difficult or impossible to install the head fixing screw 50. In this regard, with the head 10 of this embodiment, the head fixing screw 50 can be inserted into the through hole 40L while tilting the head fixing screw 50 to avoid interference with the clamp member 60 (see FIG. 6), and after inserting it to a certain extent, the head fixing screw 50 can be made parallel to the central axis 10X (and central axis 80X) and turned to be fastened (see FIGS. 3 to 6).

[0039] Counterbore 41 is provided around each of the plurality of through holes 40 described above (see FIGS. 6, 7, etc.). At least one of the plurality of counterbore 41 may have a shape in which a portion thereof opens onto the circumferential surface 31 of the cylindrical portion 30. By removing in advance portions that will become thinner due to the provision of counterbore 41, it is possible to reduce the risk of cracks occurring during or after molding. In the head 10 of this embodiment, all of the counterbore 41 provided in each of the three through holes 40 have a shape in which they open onto the circumferential surface 31 of the cylindrical portion 30 (see FIGS. 7, 10, etc.).

[0040] Furthermore, the head 10 is provided with ribs 42 and recessed portions 43. Of these, the ribs 42 are shaped to connect to any of the counterbore portions 41, and are provided so as to ensure strength at predetermined locations while achieving weight reduction. In this embodiment, the ribs 42 located at the upper left in FIG. 10 are Countersink 41 It extends from the cylindrical portion 30 to the head front portion 20 in a manner that is continuous with the Bill The ribs 42 are provided in a shape similar to that of the ribs 42 (see Fig. 2, Fig. 10, etc.). The portion where the ribs 42 are provided corresponds to an area where a large bending stress acts during cutting or an area close to such an area.

[0041] The lightening recess 43 is formed by removing a portion of the head 10 to ensure a certain strength while reducing the weight of the head 10. Incidentally, when removing the same area / volume, since the principal component of the cutting force acts mainly in the vertical direction, if the bending stress in the vertical direction is emphasized, it can be said that the more the shape of the recess when viewed from the front is closer to an I-shape, the easier it is to obtain a moment of inertia (see FIG. 10 ). In this embodiment, the lightening recess 43 is formed so that the depth of the recess increases toward the tip 10t of the head 10 (see FIGS. 2, 9, etc.). In other words, the lightening recess 43 has a shape that approaches the center of the head front portion 20 (i.e., the central axis 10X of the head 10) toward the tip 10t of the head 10 (see FIG. 10, etc.).

[0042] The clamp member 60 is a member for clamping and fixing (together with the shim 61 in this embodiment) the cutting insert 70 attached to a predetermined position on the mounting seat 21. The clamp member 60 of this embodiment has the leg portions 60L, the pressed surface 60P, the clamp inclined surface 60S, and the protrusion 60T as described above. The protrusion 60T is fitted into the through-hole 72 in the center of the cutting insert 70 attached to a predetermined position on the mounting seat 21, the end of the leg portion 60L is inserted into the clamp recess 11C of the first flat surface 11, and the clamp inclined surface 60S is brought into contact with the third flat surface 13. Then, the clamp fixing screw 63 is passed through the clamp fixing screw hole 11H, and the clamp fixing screw 63 is turned to press the pressed surface 60P, thereby clamping the cutting insert 70 and the like (see FIGS. 3 to 5).

[0043] The head 10, with the cutting insert 70 and the like clamped and fixed by the clamp member 60, can be attached to or detached from the head mounting surface 84 of the shank 80 by tightening or loosening the head fixing screw 50 (see Figures 3, 6, etc.). When the head 10 is attached to the head mounting surface 84, the serrations S on the base end surface 35 and the serrations S on the head mounting surface 84 mesh with each other, thereby uniquely defining the relative position of the head 10 to the shank 80 in one direction (the vertical direction in which the sawtooth peaks and valleys are aligned). Furthermore, by tightening the head fixing screw 50, the relative position of the head 10 to the shank 80 in the lateral direction is also uniquely defined.

[0044] [Cutting insert] The cutting insert 70 cuts into the workpiece (material to be cut) 100 using a cutting edge 71. The cutting insert 70 shown in the drawings (Fig. 3, etc.) has three corners on each side, for a total of six corners on both sides, but this is merely an example, and other structures, such as a cutting insert 70 with two corners on each side, for a total of four corners on both sides, may also be used. Furthermore, the cutting insert 70 shown in the drawings (Fig. 3, etc.) is a negative insert with no clearance angle, but a positive insert with a clearance angle may be used instead.

[0045] According to the replaceable-head cutting tool 1 of this embodiment, the surface roughness of the mounting seat 21, which is the mounting area of ​​the cutting insert 70, is reduced, for example, by cutting, to improve mounting accuracy, while the remaining portions are left as the surface texture of the additive manufacturing process. This configuration makes it possible to overcome the deterioration of accuracy when mounting components while maintaining the benefits of additive manufacturing. In particular, this embodiment is characterized in that the surface roughness of both the first plane 11 and the wall surface 23, which form the ridge line 15, is reduced, for example, by cutting, to smooth the surfaces, thereby increasing the positional accuracy of the ridge line 15 and further improving the positioning accuracy of the restraining position of the cutting insert 70. This replaceable-head cutting tool 1 improves the repeatability during corner changes of the cutting insert 70 and the repeatability during replacement of the head 10, thereby improving the machining accuracy of the workpiece 100. From a similar perspective, in this embodiment, the surface roughness of the cylindrical upper flat surface 32, which is used for phase determination using a height gauge, is also reduced, for example, by cutting. Another advantage is that the head 10 produced by additive manufacturing is inexpensive and lightweight.

[0046] The exchangeable head cutting tool 1 is used for internal turning and the like with the head 10, having the cutting insert 70 mounted on the mounting seat 21, attached to the shank 80. The machining direction of the exchangeable head cutting tool 1 is not particularly limited. The exchangeable head cutting tool of this embodiment can be applied to both front turning, in which the exchangeable head cutting tool 1 is moved in the direction of the tip end 10t of the head 10, and back turning, in which the exchangeable head cutting tool 1 is moved in the opposite direction, toward the base end 10b (see FIGS. 11 and 12).

[0047] The above-described embodiment is one example of a preferred embodiment of the present invention, but is not limited thereto and various modifications are possible without departing from the spirit and scope of the present invention. For example, the above-described embodiment has been described by exemplifying the structure of an exchangeable head 10 that can be attached to and detached from a shank 80. However, the head 10 and the exchangeable-head cutting tool 1 including the head 10 are merely one preferred embodiment of the tool body according to the present invention. For example, the feature of reducing the surface roughness of the mounting seat 21 of the cutting insert 70 by machining or the like, while leaving the remaining parts as they are, thereby overcoming the deterioration of accuracy when attaching components while retaining the advantages of additive manufacturing, can also be applied to other tool bodies, such as cutting tools that do not have exchangeable heads, such as tool bodies of a so-called shank-integrated type in which the head (the part corresponding to the head 10) is integrated with the shank, or tool bodies of cutting tools (such as external turning tools and grooving tools) in which the head (the part corresponding to the head 10) is integrated with the main body part, such as the shank, of the cutting tool by brazing. The head portion (the portion corresponding to the head 10) and the shank can be joined and integrated by brazing, welding, adhesive, or the like. [Industrial Applicability]

[0048] The present invention is suitable for application to cutting tools and tool bodies thereof. [Explanation of symbols]

[0049] 1...Replaceable head cutting tool (cutting tool) 10...Head (tool body) 10b...Proximal end 10t...Tip 10X…center axis 11…1st plane 11C...Clamp recess 11H...Clamp fixing screw hole 12…Second plane 13…Third plane 15... Ridge line (formed between the wall surface and the first plane) 20...Front of head 21...Mounting seat 22...(mounting seat) bottom 22b…Second bottom surface 22w...wall 23...(Mounting seat) wall 24...Screw hole for fixing the shim 30...Cylindrical part 31...peripheral surface 32...Upper flat surface of cylinder 33...Cylinder bottom flat surface 34...Flat surface of cylinder side 35...Proximal surface 40...Through hole 40L…long hole 41...Recess 42...Rib 43...Lightweight recess 46...Coolant inlet 47...Cylindrical connecting member 50...Head fixing screw (fixing member) 60...Clamping member 60L…legs 60P...Pressure surface 60S...Clamp inclined surface 60T…projection 61... Deposit 62... Shim fixing screw 63...Clamp fixing screw 70...Cutting insert 71...Cutting edge 72...Through hole 80...Shank 80t...tip 80X…center axis 81...peripheral surface 82A…Gripped surface 82B…Flat surface 83...Gripped part 84...Head mounting surface 85...Coolant passage 86...Coolant outlet 87...Head fixing screw hole S...Serration (saw-tooth part) 100...Workpiece (material to be cut)

Claims

1. 1. A tool body of a cutting tool, comprising: a mounting seat for a cutting insert provided on the tip end side along the central axis; a cylindrical portion provided on a base end side opposite to the tip end portion along the central axis; Equipped with the surface roughness of the mounting seat is smaller than the surface roughness of the circumferential surface of the cylindrical portion, a first plane adjacent to a wall surface rising from the bottom surface of the mounting seat and forming a ridge between the first plane and the wall surface; and a second plane adjacent to the first plane and lower than the first plane and higher than the bottom surface, wherein the surface roughness of the first plane is equal to the surface roughness of the mounting seat and is smaller than the surface roughness of the second surface.

2. 2. The tool body of claim 1, further comprising a third plane adjacent to the first plane and inclined at a constant angle relative to the first plane, wherein the surface roughness of the third plane is equivalent to the surface roughness of the first plane.

3. 2. The tool body according to claim 1, wherein the cylindrical portion has a cylindrical upper flat surface formed by cutting out a portion of the circumferential surface of the cylindrical portion, and the surface roughness of the cylindrical upper flat surface is smaller than the surface roughness of the circumferential surface.

4. 4. The tool body according to claim 3, further comprising: a cylindrical bottom flat surface provided on a portion opposite to the cylindrical top flat surface; and a cylindrical side flat surface provided on a side of the peripheral surface, wherein the surface roughness of the cylindrical bottom flat surface and the cylindrical side flat surface is equivalent to the surface roughness of the peripheral surface.

5. The tool body according to claim 1 , wherein the tool body has an exchangeable head that is detachable from the shank.

6. 6. The tool body according to claim 5, further comprising: a plurality of through holes penetrating the cylindrical portion from a base end surface facing the base end side toward the tip end side; counterbores around the through holes; at least one rib having a shape continuing to any of the counterbores; and at least one lightening recessed portion having a shape continuing to any of the counterbores.

7. A tool body of a cutting tool, comprising: a mounting seat for a cutting insert provided on the tip end side along the central axis; a cylindrical portion provided on a base end side opposite to the tip end portion along the central axis; a plurality of through holes that penetrate the cylindrical portion from a base end surface facing the base end side toward the tip end side; a counterbore around the through hole; At least one rib connected to any one of the counterbores; At least one recessed portion having a shape connected to any one of the counterbore portions; Equipped with the surface roughness of the mounting seat is smaller than the surface roughness of the circumferential surface of the cylindrical portion, The tool body is an interchangeable head that can be attached to the shank.

8. The tool body according to claim 6 , wherein the recessed portion has a shape in which the depth of the recessed portion increases toward the tip end portion.

9. The device further comprises a third plane adjacent to the first plane and inclined at a certain angle relative to the first plane, The tool body according to claim 6 , wherein the rib is shaped to connect to at least one of the plurality of counterbores.

10. The tool body of claim 6 , wherein at least one of the plurality of through holes is an elongated hole.

11. The tool body according to claim 6 , wherein at least one of the plurality of counterbores has a shape in which a part thereof opens onto the circumferential surface of the cylindrical portion.

12. The tool body according to claim 5 , wherein a base end surface of the cylindrical portion facing the base end side is configured with a sawtooth portion, and the surface roughness of the sawtooth portion is smaller than the surface roughness of the circumferential surface of the cylindrical portion.

13. The tool body according to claim 1 , further comprising a head joined to a shank, the cylindrical portion being disposed on the head.

14. A cutting tool comprising a tool body according to any one of claims 1 to 4.

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