Cutting tool with at least partially shaped body and method for its manufacture

Abstract

Cutting tool for performing cutting operations on a workpiece when the cutting tool (10; 10''; 10'') is rotated about a central axis (11) by a machine tool, wherein the cutting tool (10; 10''; 10'') comprises the following: a generally cylindrical body (12) arranged around the central axis (11), wherein the generally cylindrical body (12) has a first end (14) and an opposite second end (16); a cutting section (17) arranged at or around the first end (14) of the generally cylindrical body (12), wherein the cutting section (17) has a number of cutting edges structured to engage with the workpiece during cutting operations, and a mounting section (22) which is arranged at or around the opposite second end (16) of the generally cylindrical body (12), wherein the mounting section (22) is structured to be coupled to the machine tool, wherein at least one section of the generally cylindrical body (12) comprises a shaped section (24; 24'; 50) which has been formed by a shaping process, wherein the shaped section (24; 24'; 50) has been formed around the cutting section (17) in such a way that the cutting section (17) is coupled to the generally cylindrical body (12), and wherein the cutting section (17) comprises a plate member (18) arranged transversely to the central axis (11) and extending over the entire width of the cutting tool (10; 10''; 10'') and coupled to the cylindrical body (12) over the shaped section (24; 24'; 50), wherein at least one cutting insert is arranged in the plate member and the cutting edges are formed on the at least one cutting insert.

Description

[0001] The invention relates generally to rotating cutting tools, and more particularly to cutting tools having a generally cylindrical body, at least a portion of which has been formed by a molding process. Furthermore, the invention relates to a method for manufacturing such cutting tools.

[0002] Rotating cutting tools such as, without limitation, drills, reamers, or end mills are typically formed entirely from hardened tool steels, from hardened tool steels coated with a hardened secondary material, or from hardened tool steels fitted with removable cutting inserts formed from other hardened materials such as, for example, polycrystalline diamond (PCD), polycrystalline cubic boron nitride (PCBN), ceramic, cemented carbide, and cermet. Although such hardened materials generally produce a desirable end product, the costs associated with manufacturing such an end product are generally undesirable because the hardened materials typically require a significant amount of time and machining to produce a final product.

[0003] Although conventional rotating cutting tools are generally suitable for many applications, there is still room for improvement. For example, a drill made from a single piece of cemented carbide, once used to the point where the cutting edges have become blunt, must either be disposed of or remanufactured. In most cases, it is only the cutting edges that are worn, not the rest of the cutting tool body. Disposal of the cutting tool obviously results in the tool being no longer used. On the other hand, remanufacturing ensures the tool's continued use, although this remanufacturing is often more limited than its original use and is generally accompanied by high remanufacturing costs.

[0004] Therefore, there is a need for improved cutting tools.

[0005] US Pat. No. 3,590,472 A discloses a method for manufacturing cutting tools and cutting inserts, as well as such cutting tools and cutting inserts. Here, boron fibers are embedded in an aligned manner in a matrix. These fibers are softer than the fibers and provide the cutting surface with greater durability. The cutting tool is manufactured, in particular, by extrusion, with the aligned boron fibers being introduced into the extrusion die.

[0006] Embodiments of the invention directed to an improved cutting tool and a method for its manufacture address disadvantages of the prior art.

[0007] As one aspect of the invention, a cutting tool is provided for performing cutting operations on a workpiece when the cutting tool is rotated about a central axis by a machine tool. The cutting tool comprises: a generally cylindrical body disposed about the central axis, the generally cylindrical body having a first end and an opposite second end;a cutting portion disposed at or about the first end of the generally cylindrical body, the cutting portion having a number of cutting edges structured to engage the workpiece during cutting operations, the cutting portion comprising a plate member disposed transversely to the central axis and extending across the entire width of the cutting tool and coupled to the cylindrical body via the shaped portion, at least one cutting insert disposed in the plate member and the cutting edges formed on the at least one cutting insert;and a mounting portion disposed at or around the opposite second end of the generally cylindrical body, the mounting portion being structured to be coupled to the machine tool. At least a portion of the generally cylindrical body includes a shaped portion formed via a molding process. The shaped portion is formed around the cutting portion in a manner that couples the cutting portion to the generally cylindrical body.

[0008] The shaped portion may be formed from fibers or particles arranged randomly or in a predetermined layered structure within a matrix material.

[0009] The cylindrical body portion may include a preformed inner core portion located at or about the central axis, and the formed portion may be formed around the inner core portion. The inner core portion may comprise a hollow tubular member or a solid cylindrical member. The inner core portion may be formed from steel or cemented carbide, or a fiber-reinforced composite material or a particle-reinforced composite material.

[0010] The shaped portion may include a number of wear-resistant elements disposed or formed therein. The wear-resistant elements may be formed from PCD and / or PCBN and / or cemented carbide and / or cermet and / or ceramic.

[0011] The cylindrical body portion may include a number of chip evacuation flutes and the shaped portion may include a number of wear-resistant and / or heat-resistant particles disposed at or around the number of flutes.

[0012] The shaped portion may comprise a number of wear-resistant metal layers and / or shims disposed at or around the mounting portion.

[0013] The shaped portion may include a number of cooling channels formed therein.

[0014] The number of cutting edges can be formed in a number of cutting inserts, which are optionally coupled with the number of plate members.

[0015] As a further aspect of the invention, a method of forming a cutting tool for use in rotary cutting operations is provided. The method comprises: providing a mold formed from one or more mold sections, the mold having a number of interior surfaces defining an interior space in the shape of the cutting tool within the mold; securing a cutting section of the cutting tool within the mold; providing a quantity of curable material within the interior space of the mold and around a portion of the cutting section to form a cutting tool within the mold; allowing the curable material to cure; and removing the cutting tool from the mold.

[0016] Further, the method may comprise disposing a core portion within the mold prior to providing the amount of curable material within the mold, and providing the amount of curable material within the mold may comprise providing the curable material around the core portion.

[0017] Further, the method may comprise arranging a number of tubular members in the mold prior to providing the amount of curable material within the mold, and providing the amount of curable material within the mold may comprise providing the material around the number of tubular members.

[0018] The amount of curable material can be provided via an injection process.

[0019] The amount of curable material can be provided by sucking the curable material into the interior of the mold via a vacuum process.

[0020] The method may further comprise providing a number of wear-resistant elements within the hardenable material.

[0021] The method may further comprise electroplating a portion of the curable material after removing the cutting tool from the mold.

[0022] A full understanding of the invention can be obtained from the following description of the preferred embodiments taken in conjunction with the accompanying drawings in which: Fig. 1 is an isometric view of a rotating cutting tool in accordance with an exemplary embodiment of the present invention; Fig. 2 a cross-sectional view of the rotating cutting tool from Fig. 1 is along the line 2-2; Fig. 3 is a cross-sectional view of a rotating cutting tool in accordance with another exemplary embodiment of the present invention; Fig. 4 is a cross-sectional view of a rotating cutting tool in accordance with yet another exemplary embodiment of the present invention; Fig. 5 is an isometric view of a portion of a rotating cutting tool in accordance with an exemplary embodiment of the invention; Fig. 6 is an isometric view of a portion of a rotating cutting tool in accordance with another exemplary embodiment of the invention; and Fig. 7 is a schematic isometric view of a mold for forming a cutting tool in accordance with an exemplary embodiment of the invention.

[0023] Directional terms used herein, such as left, right, front, back, top, bottom, and derivatives thereof, refer to the orientation of the elements shown in the drawings and, unless expressly stated otherwise, are not limiting of the claims. Like parts are designated by the same reference numeral throughout the drawings.

[0024] As used here, the term “number” shall refer to any non-zero quantity (that is, one or any quantity greater than one).

[0025] Fig. 1 illustrates an exemplary cutting tool in accordance with a non-limiting embodiment of the present invention for performing rotary cutting operations on a workpiece (not shown) when the cutting tool 10 is rotated about a central longitudinal axis 11. The cutting tool 10 includes a generally cylindrical tool body 12 having a first end 14 and an opposite second end 16. Although the cutting tool 10 is shown in the form of a reamer, it will be appreciated that the concepts described herein may also be applied to other rotary cutting tools such as, for example, but not limited to, drills (e.g., single flute, multi-flute, helical, straight), modular drills, stepped drills, end mills, face mills, parting bits, lathe bits, boring bars, mortise drills, taps, and circular saws.

[0026] Continue with Fig. 1, the cutting tool 10 includes a cutting portion 17 generally disposed at or about the first end 14, which is structured to engage and perform cutting operations on a workpiece (not shown) when the cutting tool 10 is rotated about the longitudinal central axis 11. In the illustrated embodiment, the cutting portion 17 includes a plate member 18 generally disposed transverse to the axis 11, having a number (two in the illustrated embodiment) of cutting portions 20 formed (either permanently or selectively) as a portion thereof or coupled thereto. In the illustrated embodiment Fig. In the embodiment illustrated in Figure 1, the cutting tool 10 is shown as a reamer, with the cutting portions 20 comprising two reamer inserts, each selectively coupled to the plate member 18 in such a manner that each insert can be selectively removed and replaced as needed due to wear from use. Such selective coupling may be accomplished by various means conventionally used in the art for coupling a removable insert to a cutting tool.

[0027] Continue with Fig. 1, the cutting tool 10 further includes a mounting portion 22 generally disposed at or about the second end 16, which is adapted to be mounted in a chuck or similar portion of a machine tool to rotate the cutting tool 10 about the axis 11. One or more flutes 23 may be provided in the tool body 12 extending from the cutting portion 17 toward the mounting portion 22 to assist in the evacuation of chips formed during cutting operations. Although straight flutes are shown in the exemplary embodiment shown, it will be appreciated that the flutes provided in the tool body 12 may also be helical, of a various quantity, or of another suitable arrangement without departing from the scope of the present invention.It will be appreciated that the cutting tool 10 may incorporate the features described above, as well as other features of known cutting tools not specifically identified herein, individually or in whole, without departing from the scope of the present invention.

[0028] The cutting tool 10 differs from known cutting tools in that the entire cylindrical body 12 or at least a portion thereof has been formed in a finished or semi-finished state from a molding process. As shown in the cross-sectional view of Fig. 2, the entire tool body 12 of the cutting tool 10 is formed as a shaped portion 24 formed via a molding process. Such a molding process is carried out using a mold such as the one schematically shown in Fig. 7. The mold 25 includes a number of interior surfaces 26 that define an interior space 28 in the shape of the outer shape of the cutting tool 10. The mold 25 is preferably formed from a suitable rigid or semi-rigid material, as is generally used for forming molds, and may be formed from or include a number of sections (not labeled) that can be coupled together to form the mold 25 and which can then be subsequently uncoupled to enable the removal of a formed cutting tool 10. The mold 25 includes one or more coupling mechanisms 30 for securing the cutting section 17 for the cutting tool 10 at a precise location within the interior space 28. Although this is not shown in Fig. 7 is shown only schematically, such coupling mechanism(s) may include clamps, screw-type precision positioning units, adhesive or pins.

[0029] Preferably, the molded portion 24 is formed from a composite material. For example, the molded portion 24 may be formed from fibers or particles randomly arranged within a curable matrix material or arranged in a predetermined layered structure. Such a curable matrix material may be pre-impregnated with the fibers and later cured during further processing, or is preferably provided in the mold 25 via an injection or vacuum process and then allowed to cure. Examples of suitable materials from which the molded portion 24 may be formed include, without limitation, reinforced plastic, carbon fiber composites, metal matrix composites, and metal alloys.

[0030] Additionally, all or selected portions of the shaped portion 24 may be formed from selected materials that are particularly resistant to high temperatures or wear. For example, areas near the cutting portion 17 are typically exposed to high heat from cutting operations along with abrasive chips. Typically, the chip evacuation portions of the tool body 12 (e.g., the flutes 23) are also exposed to such conditions. The portions 24' of the shaped portion 24 made of Fig. 1 show some non-limiting examples of such regions which are desired to be formed from temperature / wear resistant materials.

[0031] Fig. 3 and Fig. 4 show cross-sectional views of exemplary cutting tools 10' and 10" in accordance with further embodiments of the present invention that include similar features as the cutting tool 10 (e.g., without limitation, flutes 23) but are formed in a somewhat different manner. In particular, the cutting tools 10' and 10" show exemplary embodiments in which a tool body 12' and 12" is formed from a shaped portion 50 formed around a pre-formed central core 52. In these examples, the shaped portion 50 is formed generally as previously discussed. As in the exemplary embodiment of Fig. 3, the core 52 may be formed from a solid cylinder member 62. As in the exemplary embodiment of Fig. 4, the core 52 may also be formed from a hollow tubular member 60. In any event, the core 52 is preferably formed from steel, cemented carbide, a fiber-reinforced composite, a particle-reinforced composite, or other suitable material. The core 52 may initially be provided in a relaxed state or, alternatively, may be prestressed prior to formation of the shaped portion 50 therearound. For example, the core 52 may initially be disposed in a radially stressed (i.e., twisted) state in a mold, such as mold 25, prior to formation of the shaped portion 50 therearound. This prestressing of the core 52 may be used to alter the bending and torsional behavior.

[0032] The hollow tubular member 60 may be used as a coolant passage to generally supply a flow of coolant to the cutting portion of the cutting tool 10" through the tool body 12". Alternatively, the tubular member 60 may be used in certain applications to provide a means for internal chip evacuation from the cutting area adjacent to the cutting portion of the cutting tool 10".

[0033] To increase the durability and overall performance of the cutting tool 10, one or more wear-resistant elements are arranged or formed therein. Such wear-resistant elements may be formed, for example, without limitation, from PCD (polycrystalline diamond) and / or PCBN (polycrystalline cubic boron nitride) and / or cemented carbide and / or cermet and / or ceramic and / or from another suitable material. For example, wear-resistant and / or heat-resistant particles may be included in the shaped portion adjacent to the flutes to form the flutes, such as previously described with respect to the portion 24' of Fig. 1, to help protect against deterioration due to contact with the hot and abrasive chips formed during cutting operations. Similarly, the portions of the formed material at or above the fillets may be coated via an electroplating process after the cutting tool has been formed in and subsequently removed from the mold 25 to provide additional protection in those portions.

[0034] As in Fig. 5, as another example, a shaped portion may include a number of wear-resistant metal layers and / or shims 70 disposed at or above the mounting portion 22 of the cutting tool 10''' to increase the strength / wear resistance of the cutting tool at or about the location where it is mounted in a machine tool (not shown).

[0035] As in Fig.6, as yet another example, the shaped portion may include a number of wear-resistant portions 72 formed therein at or around the leading end (i.e., the first end 14) of the cutting tool, which serve as guide rails for the cutting tool. Accordingly, the portions 72 typically extend slightly outwardly from the tool body 12. In addition to wear-resistant elements, other useful elements can easily be integrated into the molded portion of the cutting tool body. As an example, rigid or semi-rigid tubular members can be provided in the mold 25 so that the molded portion is generally formed therearound. When such a molded portion is formed and the cutting tool is removed from the mold, these tubular members can be used as cooling channels to aid in reducing temperatures in the tool body and / or the cutting portion during cutting operations.

Claims

[1] Cutting tool for performing cutting operations on a workpiece when the cutting tool (10; 10''; 10'') is rotated by a machine tool about a central axis (11), the cutting tool (10; 10''; 10'') comprising: a generally cylindrical body (12) disposed about the central axis (11), the generally cylindrical body (12) having a first end (14) and an opposite second end (16); a cutting portion (17) disposed at or around the first end (14) of the generally cylindrical body (12), the cutting portion (17) having a number of cutting edges structured to engage the workpiece during cutting operations, and a mounting portion (22) disposed at or around the opposite second end (16) of the generally cylindrical body (12), the mounting portion (22) being structured to be coupled to the machine tool, wherein at least a portion of the generally cylindrical body (12) comprises a shaped portion (24; 24'; 50) formed via a molding process, wherein the shaped portion (24; 24'; 50) has been formed around the cutting portion (17) in such a way that the cutting portion (17) is coupled to the generally cylindrical body (12), and wherein the cutting portion (17) comprises a plate member (18) arranged transversely to the central axis (11) and extending over the entire width of the cutting tool (10; 10''; 10'') and coupled to the cylindrical body (12) via the shaped portion (24; 24'; 50), wherein at least one cutting insert is arranged in the plate member and the cutting edges are shaped on the at least one cutting insert. [2] A cutting tool according to claim 1, wherein the shaped portion (24; 24') comprises fibers or particles arranged randomly or in a predetermined layered structure and disposed within a matrix material. [3] A cutting tool according to claim 1 or 2, wherein the cylindrical body (12) comprises a pre-shaped inner core portion disposed at or around the central axis (11), and wherein the shaped portion (50) is formed around the inner core portion. [4] Cutting tool according to claim 3, wherein the inner core portion comprises a hollow tubular member (60) or a solid cylindrical member (62). [5] Cutting tool according to claim 3 or 4, wherein the inner core portion is formed of steel or cemented carbide or a fiber-reinforced composite material or a particle-reinforced composite material. [6] A cutting tool according to any one of the preceding claims, wherein the shaped portion (24; 24'; 50) comprises a number of wear-resistant elements arranged or formed therein. [7] Cutting tool according to claim 6, wherein the wear-resistant elements are formed from PCD and / or PCBN and / or cemented carbide and / or cermet and / or ceramic. [8] Cutting tool according to one of the preceding claims, wherein the cylindrical body (12) includes a number of chip evacuation flutes (23) and wherein the shaped portion (24; 24'; 50) comprises a number of wear-resistant and / or heat-resistant particles arranged at or around the number of chip evacuation flutes (23). [9] Cutting tool according to one of the preceding claims, wherein the shaped portion (24; 24'; 50) comprises a number of wear-resistant and / or heat-resistant metal layers and / or shims arranged at or around the mounting portion (22) and / or the cutting portion (17). [10] A cutting tool according to any one of the preceding claims, wherein the shaped portion (24; 24'; 50) comprises a number of cooling channels formed therein. [11] Cutting tool according to one of the preceding claims, wherein the plurality of cutting edges are formed in a plurality of cutting inserts which are selectively coupled to the plurality of plate members (18). [12] A method of forming a cutting tool (10; 10''; 10'') for use in rotary cutting operations, the method comprising: Providing a mold (25) formed from one or more mold sections, the mold (25) having a number of interior surfaces (26) defining within the mold (25) an interior space (28) in the shape (25) of the cutting tool (10; 10''; 10''); Fixing a cutting portion of the cutting tool (10; 10''; 10'') within the mold (25); Providing a quantity of curable material within the interior (28) of the mold (25) and around a portion of the cutting section to form a cutting tool (10; 10''; 10'') within the mold (25); Allow the curable material to harden; Removing the cutting tool (10; 10''; 10'') from the mold (25). [13] The method of claim 12, further comprising disposing a core portion within the mold (25) prior to providing the amount of curable material within the mold (25), and wherein providing the amount of curable material within the mold (25) comprises providing the curable material around the core portion. [14] The method of claim 12 or 13, further comprising arranging a number of tubular members (60) in the mold (25) prior to providing the amount of curable material within the mold (25), and wherein providing the amount of curable material within the mold (25) comprises providing the material around the number of tubular members (60). [15] A method according to any one of claims 12 to 14, wherein the amount of curable material is provided via an injection process. [16] Method according to one of claims 12 to 15, wherein the amount of curable material is provided by sucking the curable material into the interior (28) of the mold (25) via a vacuum process. [17] A method according to any one of claims 12 to 16, further comprising providing a number of wear-resistant elements within the hardenable material. [18] The method of any one of claims 12 to 17, further comprising electroplating a portion of the curable material after removing the cutting tool (10; 10''; 10'') from the mold (25).

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