Rotary cutting tool having a support structure

Abstract

The rotary cutting tool includes a support structure having a central hub located at an axial rearward end of the rotary cutting tool. A plurality of primary support members extend from the central hub in different axial and radial directions in three-dimensional space relative to a central rotational axis of the rotary cutting tool. The support structure may include one or more secondary support members extending from the primary support member in different axial and radial directions in three-dimensional space, and one or more tertiary support members for increasing the stiffness of the support structure. The central hub extends in a plane substantially perpendicular to the central rotational axis of the rotary cutting tool. In one embodiment, each of the plurality of primary support members has a different physical dimension.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE In general, the present invention relates to cutting tools, and more particularly to lightweight rotary cutting tools, such as rotary drilling tools, that include a support structure having a plurality of support members having geometric arrangements and physical dimensions determined using topology optimization techniques, and that are manufactured using additive manufacturing. [Background technology]

[0002] (Background to the disclosure) In certain machining applications, the weight of a cutting tool can be a significant constraint. Heavy tools are problematic for operators who must handle the tool. In addition, the time to accelerate and decelerate a tool to its desired speed decreases with the reduction in the weight and moment of inertia of the tool. Furthermore, large, heavy tools become difficult or impractical to move by hand, thereby necessitating the use of automatic tool changers. Still further, heavy cutting tools can cause tool change efficiency issues or even result in reduced machining quality if the tool's tilting moment is too high for the machine connection. Hence, there is a need to minimize the weight of conventional heavy cutting tools while maintaining adequate rigidity to allow for easier handling and reduced operating costs. Summary of the Invention

[0003] (Summary of disclosure) The challenge of reducing the weight of rotary cutting tools, such as reamers, is solved by using topology optimization techniques combined with additive manufacturing (i.e., 3D printing) to generate support structures that significantly reduce the overall weight of the rotary cutting tool while maintaining its strength, stiffness, and functionality.

[0004] Topology optimization uses Finite Element Analysis (FEA) or Finite Element Method (FEM) to optimize the distribution of material in a structure for a given volume, based on the loads and constraints applied. The current proliferation of 3D printer technology has enabled designers and engineers to use topology optimization techniques when designing new products. Topology optimization combined with 3D printing can result in lighter weight, improved structural performance, and shorter design-to-manufacturing cycles.

[0005] The geometric arrangement and physical dimensions of each support member of the support structure for the rotary cutting tool are determined using topology optimization techniques to provide a support structure with the highest possible stiffness-to-weight ratio for a given material, volume, and loads / constraints. The support structure of the present invention has complex geometries that can be combined with 3D printing, thereby resulting in a lightweight structure with improved structural performance.

[0006] In one aspect, the rotary cutting tool includes a support structure including a central hub located at an axial rearward end of the rotary cutting tool and a plurality of support members extending in different axial and radial directions in three-dimensional space relative to a central rotational axis of the rotary cutting tool. The pocket area is supported by one of the plurality of support members. The rotary cutting tool further includes an adapter connected to the central hub for connecting the support structure to a rear machine connection member, the central hub extending in a plane substantially perpendicular to the central rotational axis of the rotary cutting tool.

[0007] In another aspect, a support structure for a rotary cutting tool includes a central hub located at an axial rearward end of the rotary cutting tool, a plurality of support members extending in different axial and radial directions in three-dimensional space relative to a central axis of rotation of the rotary cutting tool, a pocket area being supported by one of the plurality of support members, each of the plurality of support members having a different physical dimension.

[0008] BRIEF DESCRIPTION OF THE DRAWINGS While various embodiments of the present invention are illustrated, the particular embodiments shown should not be construed as limiting the scope of the claims, and it is anticipated that various changes and modifications may be made without departing from the scope of the present invention. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a front perspective view of a rotary cutting tool, such as a rotary drilling tool, according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a rear perspective view of the rotary cutting tool of FIG. [Diagram 3] FIG. 3 is a side view of the support structure of the rotary cutting tool of FIG. [Figure 4] 4 is another side view of the support structure of the rotary cutting tool of FIG. 1. FIG. [Diagram 5] 5 is a rear view of the support structure of the rotary cutting tool of FIG. 1. FIG. [Figure 6] FIG. 6 is a cross-sectional view of the support structure taken along line 6-6 of FIG. [Figure 7] FIG. 7 is a cross-sectional view of the support structure taken along line 7-7 of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] (Detailed Description of Disclosure) 1-5, there is shown a rotary cutting tool 10 according to one embodiment of the present invention. In the illustrated embodiment, the rotary cutting tool 10 comprises a rotary drilling tool that rotates in a direction R during operation about a central axis of rotation RA. Although in the illustrated embodiment, the rotary cutting tool 10 comprises a rotary drilling tool, it will be appreciated that the principles of the present invention may be applied to any cutting tool for metal cutting operations, such as milling cutters, reamers, and the like. Additionally, the description herein of a particular application should not be construed as limiting the scope and extent of use of the rotary cutting tool.

[0011] Directional terms used herein, such as, for example, left, right, front, back, up, down, and derivatives thereof, relate to the orientation of the elements illustrated in the drawings and do not limit the scope of the claims unless expressly stated in the claims. Identical parts are provided with the same reference numerals in all drawings.

[0012] Approximate language as used herein throughout the specification and claims may be applied to modify any quantitative expression that may be permissibly varied without resulting in a change in the basic function to which it relates. Thus, values ​​modified by terms such as "about," "approximately," "substantially," and the like are not limited to the exact value specified. In at least some cases, approximation language may correspond to the precision of an instrument for measuring the value. Here, and throughout the specification and claims, range limitations may be combined and / or interchanged, and such ranges are specified and include all subranges contained therein, unless otherwise indicated by context or language.

[0013] Throughout the text and claims, use of the word "about" in relation to ranges of values ​​(e.g., "about 22-35% by weight") is intended to modify both the upper and lower values ​​set forth and reflects around the variability associated with measurements, significant numerical values, and interchangeability, all as understood by those of ordinary skill in the art to which the invention pertains.

[0014] For purposes of this specification (other than the working examples), unless otherwise indicated, all numbers expressing quantities and ranges of ingredients, process conditions, and the like, should be understood in all instances to be modified by the term "about." Accordingly, the numerical parameters set forth in this specification and the appended claims are approximations that may vary depending on the desired results sought to be obtained by the present invention, unless otherwise indicated. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Furthermore, as used in this specification and the appended claims, the singular forms "a," "an," and "the" are intended to include plural referents unless expressly and clearly limited to one referent.

[0015] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values ​​set forth in the specific examples are reported as precisely as possible. However, any numerical value inherently contains certain errors necessarily resulting from the standard deviation (including the standard deviation found in the measuring instruments) found in their respective testing measurements. It is also to be understood that any numerical range described herein is intended to include all subranges subsumed therein. For example, a range of "1 to 10" is intended to include all subranges between the stated minimum value of 1 and the stated maximum value of 10, and all subranges including the stated minimum value of 1 and the stated maximum value of 10, i.e., ranges having a minimum value of 1 or more and a maximum value of 10 or less. The disclosed numerical ranges are continuous, and therefore include every value between the minimum and maximum values. Unless expressly indicated otherwise, the various numerical ranges specified in this application are approximations.

[0016] In the following specification and claims, reference will be made to a number of terms that have the following meanings.

[0017] The singular forms "a," "an," and "the" include plural referents unless the context clearly indicates otherwise.

[0018] "Optional" or "optionally" means that the subsequently described event or circumstance may or may not occur, and that the description includes cases where the event occurs and cases where it does not occur.

[0019] As used herein, the term "3D printing" or "additive manufacturing" is the construction of a three-dimensional object from a CAD model or digital 3D model. The term "3D printing" can refer to a variety of processes in which materials are added together, typically layer by layer (such as liquid molecules or powder particles fused together), whereby materials are deposited, bonded, or solidified under computer control to create a three-dimensional object.

[0020] As used herein, the term "topology" is defined as the way in which component parts are connected or arranged with each other.

[0021] As used herein, the phrase "topology optimization" is defined as a mathematical method that optimizes material layouts within a given design space for a given set of loads, boundary conditions, and constraints with the goal of maximizing the performance of the system. Topology optimization differs from shape and size optimization in the sense that the design can achieve any shape within the design space instead of working with predefined configurations. Traditional topology optimization techniques use finite element analysis (FEA) or finite element method (FEM) to evaluate design performance. The design is optimized using either gradient-based mathematical programming techniques, such as optimality criteria algorithms, and non-gradient-based algorithms, such as the method of moving asymptotes (MMA), or genetic algorithms. There are various commercially available software programs for topology optimization, including, but not limited to, Ansys Mechanical, Altair Inspire, Siemens NX, and Solidworks.

[0022] As used herein, the phrase "physical dimensions" of a support member is defined as the length and cross-sectional area of ​​the support member.

[0023] As used herein, the term "cantilever" is defined as a rigid structural element that extends horizontally and is supported at only one end.

[0024] As used herein, the term "void" is defined as completely empty space.

[0025] Generally, the rotary cutting tool 10 includes an axial forward end 12 and an axial rearward end 14. A support structure, generally shown at 16, includes a central hub 18 located adjacent an adapter 20 for mounting the support structure 16 to a rear machine connection member 22 at the axial rearward end 14 of the rotary cutting tool 10.

[0026] As shown in Figure 4, the central hub 18 extends in a plane P that is substantially perpendicular to the central rotational axis RA of the rotary cutting tool 10. In addition, the central hub 18 has an asymmetric, non-circular cross-sectional shape, as indicated by the dashed lines in Figures 2 and 5. In the illustrated embodiment, for example, the central hub 18 is substantially star-shaped.

[0027] In the illustrated embodiment, the support structure 16 includes three different types of support members: 1) primary support member 24; 2) secondary support member 26; and 3) A tertiary support member 28 is provided. The number and size of the tertiary support members 28 will depend on the centrifugal and cutting forces exerted on the support structure 16 during use and may be provided to prevent distortion of the support structure 16 during cutting operations. It should be noted that the secondary support members 26 and / or the tertiary support members 28 may not be necessary and may be omitted from the support structure 16 depending on the centrifugal and cutting forces exerted on the support structure 16.

[0028] Generally, the primary support members 24 extend from the central hub 18 to either the secondary support members 26 or the pocket regions 30. In the illustrated embodiment, the support structure 16 has multiple primary support members 24 that extend axially and radially outward from the central hub 18 in different directions in three-dimensional space. Generally, the primary support members 24 have a larger cross-sectional area (i.e., thickness) than either the secondary support members 26 or the tertiary support members 28. However, some tertiary support members 28 may have a larger cross-sectional area than the primary support members 24 and / or the secondary support members 26. Additionally, the cross-sectional area of ​​each of the primary support members 24 varies along its length. Furthermore, each of the primary support members 24 has different physical dimensions, such as length, thickness, and the like.

[0029] Generally, a secondary support member 26 extends from a primary support member 24 into a pocket region 30 or from another secondary support member 26 into a pocket region 30. In the illustrated embodiment, the support structure 16 has multiple secondary support members 26 that extend in different directions in three-dimensional space. Typically, the secondary support members 26 have a smaller cross-sectional area (i.e., thickness) than the primary support members 24, but may not necessarily have a larger cross-sectional area than the tertiary support members 28. In addition, the cross-sectional area of ​​each of the secondary support members 26 varies along its length. Furthermore, each of the secondary support members 26 has different physical dimensions, such as length, thickness, and the like.

[0030] As mentioned above, the cross-sectional area of ​​each of the plurality of primary support members 24 is generally larger than the cross-sectional area of ​​each of the plurality of secondary support members 26. It is noted that the size of the primary support members 24 depends on the force exerted on the pocket region 30 during the cutting operation. Specifically, the higher the force exerted on the pocket region 30, the larger the cross-sectional area of ​​the corresponding support member 24, 26. Thus, it is possible that one or more of the secondary support members 26 can have a larger cross-sectional area than one or more of the primary support members 24.

[0031] In general, the tertiary support members 28 extend from a primary support member 24 to another primary support member 24, from a primary support member 24 to a secondary support member 26, from a secondary support member 26 to another secondary support member 26, or from a pocket region 30 to another pocket region 30. In addition, the tertiary support members 28 may extend from a primary support member 24 to a central hub 18, from another tertiary support member 28 to a pocket region 30, and from one tertiary support member 28 to another tertiary support member 28. In the illustrated embodiment, the support structure 16 has multiple tertiary support members 28 that extend in different directions in three-dimensional space. In general, the cross-sectional area (i.e., thickness) of the tertiary support member 28 depends on the amount of support required for that particular region of the support structure 16. The greater the force exerted on the support structure 16, the greater the cross-sectional area of ​​the tertiary support member 28, and vice versa. In addition, the cross-sectional area of ​​each of the tertiary support members 28 varies along its length. Additionally, each of the tertiary support members 28 has different physical dimensions, such as length, thickness, and the like.

[0032] It will be appreciated that the present invention is not limited to a support structure 16 having all three different types of support members 24, 26, 28, and that the present invention may be practiced with a support structure 16 having any number of different types of support members 24, 26, 28. For example, the support structure 16 may include only a plurality of primary support members 24, depending on the design requirements of the support structure 16. In another example, the support structure 16 may include only a plurality of primary support members 24 and one or more secondary support members 24, depending on the design requirements of the support structure 16. However, in all embodiments, the support structure 16 will include at least one primary support member 24 extending from the central hub 18.

[0033] As discussed above, each of the primary support member 24, secondary support member 26, and tertiary support member 28 generally have different physical dimensions and extend in different directions in three-dimensional space. As a result, the support structure 16 is asymmetrical with respect to the central axis of rotation RA of the rotary cutting tool 10. The support structure 16 may include one or more balance masses 38 for rotationally balancing the support structure 16 about the central axis of rotation RA, if desired. However, it will be appreciated that the support structure 16 may be substantially symmetrical about the central axis of rotation RA of the rotary cutting tool 10, depending on the design requirements discussed above. In that case, the balance mass 38 is not necessary and may be omitted. It may also be possible to rotationally balance an asymmetric support structure 16, in which case the balance mass 38 may be omitted.

[0034] As mentioned above, the support structure 16 includes a number of pocket areas 30 supported by the support structure 16. Of course, each pocket area 30 can support a cutting member, such as an insert-receiving cartridge with a cutting insert mounted therein, a cutting insert mounted in an insert-receiving pocket, etc. In the illustrated embodiment, for example, each pocket area 30 receives an insert-receiving cartridge 31 with a cutting insert 32 mounted therein, as shown in FIG. 1. Alternatively, the cutting insert 32 can be mounted directly in an insert-receiving pocket of a type known in the art. Because the primary support member 24 and the secondary support member 26 extend radially outward at different axial positions in three-dimensional space, the pocket areas 30 are cantilevered from the central hub 18 at different axial and radial positions in three-dimensional space relative to the central axis of rotation RA. In the illustrated embodiment, the pocket areas 30 can include an optional boss 40 to provide sufficient material to secure the cutting member to the pocket area 30, as shown in FIGS. 1, 3 and 4. Because each of the primary support arms 24 and the second support arms 26 extend differently in three-dimensional space (i.e., in the x-, y-, and z-directions), each of the pocket areas 30 is located in three-dimensional space at a different position relative to the central hub 18 of the rotary cutting tool 10.

[0035] 3-5, central hub 18 has an outer surface 18a facing the rear of the rotary cutting tool 10 that is substantially non-planar. To properly couple support structure 16 to adapter 20, support structure 16 also includes a coupling interface 34 having a substantially planar outer surface 34a. In the illustrated embodiment, coupling interface 34 may be formed integrally with support structure 16 using additive manufacturing (i.e., 3D printing).

[0036] The support structure 16 also includes one or more voids 36 between each of the primary, secondary, and tertiary support members 24, 26, and 28. Some of the voids 36 extend completely through the central hub 18. The voids 36 reduce the overall weight of the rotary cutting tool 10, while the support members 24, 26, 28 maintain the stiffness of the rotary cutting tool 10, thereby significantly increasing the stiffness-to-weight ratio of the rotary cutting tool 10.

[0037] 6 and 7, one or more of the primary support members 24, one or more of the secondary support members 26, and one or more of the tertiary support members 28 may have internal cavities 44, 46, 48, respectively, that extend the entire length of the support members 24, 26, 28 and may help to further reduce the weight of the rotary cutting tool 10 and aid in rotational balancing of the rotary cutting tool 10. In addition, the central hub 18 may also include an internal cavity 50 to further reduce the weight and aid in rotational balancing of the rotary cutting tool 10.

[0038] The internal cavities 44, 46, 48 of the support members 24, 26, 28 may define fluid channels that allow fluid to be transported from the fluid inlets 52 of the rear machine connection member 22 to the pocket regions 30. Of course, each pocket region 30 has the ability to deliver fluid to the cutting insert / workpiece interface, if desired. However, it should be understood that some of the internal cavities 44, 46, 48 of the support members 24, 26, 28 are not used to transport fluid, but are instead used to reduce the overall weight of the support structure 16.

[0039] 6 and 7, each of the fluid transporting internal cavities 44, 46, 48 may vary in cross-sectional area depending on the fluid flow required to provide a sufficient amount of fluid to the pocket region 30. As a general rule of thumb, support members 24, 26, 28 having a relatively larger cross-sectional area (i.e., thickness) will have a relatively larger internal cavity portion to reduce the overall weight of the support structure 16. In addition, it will be understood that the present invention is not limited by the number, size, and / or shape of the internal cavities 44, 46, 48, and that the present invention may be practiced with one or more internal cavities 44, 46, 48 having any desired size and shape to reduce the weight of the support structure 16, as long as sufficient fluid flow is provided to the insert / workpiece interface of the cutting insert 32, if desired.

[0040] As described above, the geometry and physical dimensions of the support structure 16 are determined using topology optimization techniques and fabricated using additive manufacturing (i.e., 3D printing). The geometry and physical dimensions of the support structure 16 depend on design considerations such as the volume, tilt moment, force, load, total mass, and the like of the rotary cutting tool 10. As a result, each of the plurality of primary support members 24, each of the plurality of secondary support members 26, and each of the plurality of tertiary support members 28 in the illustrated embodiment have different physical dimensions. In addition, the physical dimensions of each primary support member 24, each secondary support member 26, and each tertiary support member 28 vary along their length.

[0041] As described above, the rotary cutting tool 10 includes a support structure 16 having a geometry and physical dimensions that are determined using topology optimization techniques and fabricated using additive manufacturing (i.e., 3D printing).

[0042] The patents and publications referenced herein are hereby incorporated by reference.

[0043] While presently preferred embodiments have been described, the invention may be embodied in other ways within the scope of the appended claims. [Explanation of symbols]

[0044] (Parts List) 10 Cutting tools (boring bars) 12 Axial forward end 14 Axial rear end 16 Support structure 18 Central Hub 18a Outer surface 20 Adapter 22 Rear mechanical connection member 24 Primary support member 26 Secondary support member 28 Tertiary support member 30 Pocket Area 31 Insert Receiving Cartridge 32 Cutting insert 34 Connecting Interface 34a outer surface 36 void 38 Balance mass 40 Boss 44 Internal cavity (primary member) 46 Internal cavity (secondary member) 48 Internal cavity (tertiary member) 50 Inner cavity (center hub) 52 Fluid inlet RA Central Rotation Axis R Rotation direction

Claims

1. 1. A rotary cutting tool, comprising:

1. A support structure comprising: a central hub located at an axial rearward end of the rotary cutting tool; a plurality of support members extending in different axial and radial directions in three-dimensional space relative to a central axis of rotation of the rotary cutting tool; a pocket area supported by one of the plurality of support members; and an adapter connected to the central hub for connecting the support structure to a rear machine connection member; A rotary cutting tool, wherein the central hub extends in a plane substantially perpendicular to the central axis of rotation of the rotary cutting tool.

2. The rotary cutting tool of claim 1 , wherein the plurality of support members comprises a plurality of primary support members, at least one primary support member extending from the central hub into the pocket region.

3. 3. The rotary cutting tool of claim 2, wherein the plurality of support members further comprises a plurality of secondary support members, at least one secondary support member extending from one of the plurality of primary support members into the pocket region or from another secondary support member into the pocket region.

4. The plurality of support members further comprises a tertiary support member, the tertiary support member comprising: a) extending from the primary support member to a second primary support member; b) extending from the primary support member to a secondary support member; c) extending from the secondary support member to a second secondary support member; d) extending from the pocket area to a second pocket area; e) extending from the primary support member to the central hub; f) extending from a second tertiary support member into said pocket region; and g) extending from the second tertiary support member to the third tertiary support member; The rotary cutting tool of claim 2 .

5. The rotary cutting tool of claim 1 , wherein the central hub has an internal cavity.

6. The rotary cutting tool of claim 1 , wherein at least one of the support members has an internal cavity.

7. The rotary cutting tool of claim 6 , wherein the internal cavity defines a fluid channel for transporting a fluid to the cutting insert.

8. The rotary cutting tool of claim 3 , wherein a cross-sectional area of ​​at least one of the plurality of primary support members is greater than a cross-sectional area of ​​at least one of the plurality of secondary support members.

9. The rotary cutting tool of claim 1 , wherein the support structure is asymmetric about the central axis of rotation of the rotary cutting tool.

10. The rotary cutting tool of claim 1 , wherein the central hub is asymmetric about the central axis of rotation of the rotary cutting tool.

11. The rotary cutting tool of claim 1 , wherein the central hub has one or more voids therethrough.

12. The rotary cutting tool of claim 1 , wherein an outer surface of the central hub is non-planar.

13. The rotary cutting tool of claim 1 , wherein the rotary cutting tool comprises a rotary drilling tool.

14. The rotary cutting tool of claim 1 , further comprising a plurality of pocket areas supported by the support structure.

15. The rotary cutting tool of claim 1 , wherein the support structure further comprises one or more balance masses for rotationally balancing the support structure about the central axis of rotation of the rotary cutting tool.

16. The rotary cutting tool of claim 1 , wherein each of the plurality of support members of the support structure is manufactured using an additive manufacturing process.

17. 1. A support structure for a rotary cutting tool, comprising: a central hub located at an axial rearward end of the rotary cutting tool; a plurality of support members extending in different axial and radial directions in three-dimensional space relative to a central axis of rotation of the rotary cutting tool; a pocket region supported by one of the plurality of support members; A support structure, wherein all of said plurality of support members have different physical dimensions.

18. The support structure of claim 17 , wherein the plurality of support members comprises a plurality of primary support members, at least one primary support member extending from the central hub.

19. 20. The support structure of claim 18, wherein the plurality of support members further comprises a plurality of secondary support members, at least one secondary support member extending from one of the plurality of primary support members into the pocket region or from another secondary support member into the pocket region.

20. The plurality of support members further comprises a tertiary support member, the tertiary support member comprising: a) extending from the primary support member to a second primary support member; b) extending from the primary support member to a secondary support member; c) extending from the secondary support member to a second secondary support member; d) extending from the pocket area to a second pocket area; e) extending from the primary support member to the central hub; f) extending from a second tertiary support member into said pocket region; and g) extending from the second tertiary support member to the third tertiary support member; 20. The support structure of claim 18.

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