A rotary cutting tool having continuous major grooves and discontinuous minor grooves intersecting to form a quadrilateral surface portion.

Abstract

A rotary cutting tool (100) has a plurality of continuous major flutes (130) arranged in a spiral relative to a plurality of discontinuous minor flutes (135), the flutes intersecting to form a plurality of teeth. Each tooth includes a first cutting edge formed by the major flutes and a second cutting edge formed by the minor flutes, the first and second cutting edges meeting at an apex and forming a portion of the periphery of a quadrilateral face portion. The face portion has a non-planar surface extending from each of the first and second cutting edges to define a flank surface for each cutting edge. The first and second cutting edges are arranged on an imaginary cylinder having a central axis coaxial with the rotation axis of the tool, and each flank surface radiates inward from the surface of the imaginary cylinder, so that the first and second cutting edges each have a gap in the direction of rotation of the tool.

Description

[Technical Field]

[0001] The present disclosure is directed to cutting tools, such as end mills, for machining workpieces, and more particularly to rotary cutting tools, in which the flute system and tooth shape of the cutting tool are engineered specifically for improved machining of fiber composite materials. The rotary cutting tool has a plurality of continuous major flutes arranged in a spiral pattern opposed by a plurality of discontinuous minor flutes, the two flute types forming teeth with first cutting edges formed by the major flutes and second cutting edges formed by the minor flutes that meet at an apex and intersect to form part of the periphery of a quadrilateral face portion of the tooth. The surface of the face portion extending from each first cutting edge and second cutting edge defines a flank for the corresponding cutting edge that is radially inward from the surface of an imaginary cylinder containing the cutting edge, thereby ensuring no surface contact between the face portion and the workpiece during machining with the tool. The cutting edges and flanks improve dynamic cutting, particularly when machining fiber composite materials. The present disclosure also relates to a method for manufacturing such a rotary cutting tool. [Background technology]

[0002] In the following discussion, reference is made to certain specific structures and / or methods. However, the following reference should not be construed as an admission that these structures and / or methods constitute prior art. Applicant expressly reserves the right to declare that such structures and / or methods are not prior art to the present invention.

[0003] Composite materials can offer performance advantages in a variety of applications, primarily due to properties such as reduced weight and increased flexibility. However, composites can also be more difficult to machine than other materials, such as metal or wood. Typical composite materials are typically composed of layers of fibers and resins bonded together at high temperatures and / or with intense pressure. Machining a composite requires cutting through these various layers of different material types, for example, by chipping, breaking, or fracturing. Each of these layers reacts differently when cut, and the heat generated by the cutting tool can cause delamination or other forms of failure if not machined correctly, leading to excessive tool wear.

[0004] Common problems when machining composite materials include, for example, delamination of the composite layers, uncut fibers, fiber tearing, uneven tool wear, and poor surface finish. These problems are caused by conditions introduced by the composite material itself and can be difficult to repair. The simple fact of simultaneously cutting a combination of materials introduces many challenges that make it difficult to properly balance the right tool and appropriate operating parameters for the job. Furthermore, when machining with conventional rotary cutting tools, astigmatism or line contact between the cutting edge and the fiber composite can result in fiber pullout, while delamination and other damage that cause jagged cutting edges are avoided.

[0005] Several types of conventional cutting tools are known for use in machining composite materials. For example, straight-fluted composite cutters are designed to prevent delamination of layered materials by applying all cutting forces radially, eliminating axial forces from a typical helical cutting edge. Cutting action can be improved by incorporating a high positive rake angle to shear the fibers and eccentricity reduction to improve blade life.

[0006] Another example is a compression cutter consisting of an up-cutting and down-cutting spiral. The upper portion of the cutting length has a right-hand cutting edge with a left spiral, and the lower portion of the cutting length has a right-hand cutting edge with a right spiral. This geometry provides opposing cutting forces that can stabilize the material removal process when cutting layered composites and prevent delamination, fiber pullout, and burrs along the surface. Compression of the top and bottom of the workpiece allows the layers to remain bonded together.

[0007] Other examples include special geometries such as cutting tools with notched chip breakers, where the flutes are all oriented in the same direction to shear the fibers and shorten the chip for improved material evacuation, and diamond-cutting composite cutters with a combination of left and right-hand teeth on the outer diameter that are down-cutting shapes but are traditionally understood to result in a poorer surface finish. Also, composite finishing cutting tools with increased contact points resulting from a gradual spiral shape and a high flute count can be used for finishing. Examples of conventional cutting tools for composite materials are shown and described at https: / / www.harveyperformance.com / in-the-loupe / tooling-machining-composites / , the contents of which are incorporated herein by reference.

[0008] Even with the above-mentioned conventional tool types available for machining composite materials, further improvements in cutting tool design are still needed to further optimize composite machining performance and minimize or prevent fiber pull-out, delamination, and other modes of failure that can result in jagged cutting edges in the finished workpiece. Summary of the Invention

[0009] The disclosed rotary cutting tool has a flute system and tooth geometry where the apex of the two cutting edges (in the machining rotation direction of the tool) is the initial point of contact with the workpiece during machining, i.e., the cutting point, and each cutting edge has a true / effective flank that ensures there is no surface contact between the face portion and the workpiece during use of the tool. Thus, the disclosed rotary cutting tool minimizes fiber pull-out, delamination, and other damage that results in jagged cutting edges that can occur due to non-point or line contact between the cutting edges and the fiber composite material seen in conventional rotary cutting tools.

[0010] Generally, the disclosed rotary cutting tool has a plurality of continuous major flutes arranged in a spiral, opposed by a plurality of discontinuous minor flutes. The intersections of the continuous major flutes and the discontinuous minor flutes form teeth, each of which includes a first cutting edge formed by the major flute and a second cutting edge formed by the minor flute. The first and second cutting edges meet at an apex and form part of the periphery of the quadrilateral face portion of the tooth, and the surface of the face portion extending from each first and second cutting edge defines a clearance face for the corresponding cutting edge that is radially inward from the surface of an imaginary cylinder containing the cutting edge, thereby ensuring no surface contact between the face portion and the workpiece during machining with the tool. The apex is the first point of contact with the workpiece being machined, and the cutting edges machine the workpiece material, initially compressing it during the penetration phase of machining, i.e., when the top and rear cutting edges penetrate the workpiece. Upon further rotation of the tool, the apex passes the point of maximum penetration depth into the workpiece, and the rotary motion of the tool causes the apex (and trailing cutting edge) to be pulled out of the workpiece. During this pulling phase, the fibers in the fiber composite material are under tension and the cutting mode is shear. The disclosed rotary cutting tool provides an improved finish on the cut surface of the workpiece because it exhibits shearing of the fibers in the fiber composite material, which reduces pull-out and other damage that can result in jagged cutting edges.

[0011] One embodiment of the disclosed rotary cutting tool includes a tool body including a longitudinal central axis of rotation, the tool body being elongated and rotatable along the longitudinal central axis of rotation; a fluted cutting end including radial circumferential and end faces, and a shank portion axially opposite the fluted cutting end; a plurality of major flutes located at the fluted cutting end, each major flute projecting radially inwardly of the tool body and including a major flute surface that extends continuously and spirally in the axial direction of the tool body; and a plurality of minor flutes located at the fluted cutting end, each minor flute projecting radially inwardly of the tool body and including a minor flute surface having a plurality of discontinuous minor flute surface portions that collectively extend spirally in the axial direction of the tool body. Two consecutively adjacent large grooves are separated from one another by a band of teeth, each of which is separated from the other by a first discontinuous groove surface portion of a first groove and a second discontinuous groove surface portion of a second groove, the first groove being consecutively adjacent to the second groove. The radially circumferential surface of each of the band of teeth defines a face portion, the face portion having a periphery including first and second side edges that meet to form an apex oriented with the two side edges opening opposite to a direction of cutting rotation of the rotary cutting tool. A first side edge of the face portion is formed by the intersection of the face portion with the groove surface of the first major groove, the first side edge defining the first cutting edge, a second side edge of the face portion is formed by the intersection of the face portion with the first discontinuous minor groove surface portion of the first minor groove, the second side edge defining the second cutting edge, a first region of the face portion extending from the first cutting edge toward the interior region of the face portion is non-planar and defines a clearance surface of the first cutting edge, and a second region of the face portion extending from the second cutting edge toward the interior region of the face portion is non-planar and defines a clearance surface of the second cutting edge.

[0012] One embodiment of a disclosed rotary cutting tool includes a tool body including a longitudinal central axis of rotation, the tool body being elongated and rotatable along the longitudinal central axis of rotation, a fluted cutting end including radial circumferential and end faces, and a shank portion axially opposite the fluted cutting end, a plurality of right-hand grooves located in the fluted cutting end, each right-hand groove projecting radially inwardly from the tool body and including a groove surface that extends helically in the axial direction of the tool body, and a plurality of left-hand grooves located in the fluted cutting end, each left-hand groove projecting radially inwardly from the tool body and including a groove surface that extends axially in the tool body, wherein the groove surface of each of the plurality of right-hand grooves is continuous along at least a majority portion of the helical length of the right-hand groove, and the groove surface of each of the plurality of left-hand grooves is discontinuous along at least a majority portion of the helical length of the left-hand groove. Two consecutively adjacent right-handed grooves are separated from one another by a plurality of teeth arranged in a band, and each tooth of the plurality of teeth arranged in a band is separated from the other tooth by a portion of one of the plurality of left-handed grooves. The radially circumferential surface of each tooth of the plurality of teeth arranged in a band defines a face portion, the face portion having a periphery including four side edges, a first set of two opposing side edges of the face portion formed by intersections of the face portion with groove surfaces of two consecutively adjacent right-handed grooves, and a second set of two opposing edges of the face portion formed by intersections of the face portion with groove surfaces of two consecutively adjacent left-handed grooves. The first opposing edges of the first set intersect with the first opposing edges of the second set to form leading apexes of the teeth, the first opposing edges of the first set defining right-hand cutting edges, the first opposing edges of the second set defining left-hand cutting edges, and the leading apexes of the teeth defining cutting points. The second opposing edges of the first set intersect with the second opposing edges of the second set to form the trailing crests of the teeth. The area of ​​the face portion extending from the right cutting edge to an imaginary line extending from the leading crest of the tooth to the trailing crest of the tooth defines the flank face of the right cutting edge, the area of ​​the face portion from the left cutting edge to an imaginary line extending from the leading crest of the tooth to the trailing crest of the tooth defines the flank face of the left cutting edge, the flank face of the right cutting edge is non-planar, and the flank face of the right cutting edge is non-planar.The non-planar flank surface of the right cutting edge intersects the non-planar flank surface of the left cutting edge at an imaginary line extending from the leading crest of the tooth to the trailing crest of the tooth to form an angle therebetween.

[0013] Another embodiment of the disclosed rotary cutting tool includes a tool body including a longitudinal central axis of rotation, the tool body being elongated and rotatable along the longitudinal central axis of rotation; a fluted cutting end including radial circumferential and end faces, and a shank portion axially opposite the fluted cutting end; a plurality of right-handed flutes located in the fluted cutting end, each right-handed flute projecting radially inwardly of the tool body and including a groove surface that extends axially in a continuous right-handed spiral; and a plurality of left-handed flutes located in the fluted cutting end, each left-handed flute projecting radially inwardly of the tool body and including a groove surface having a plurality of discontinuous groove surface portions that collectively extend axially in a left-handed spiral. Two consecutively adjacent right-handed grooves are separated from one another by a plurality of teeth arranged in a band, each tooth of the band of teeth being separated from the other by a first discontinuous groove surface portion of the first left-handed groove and a second discontinuous groove surface portion of the second left-handed groove, the first left-handed groove being consecutively adjacent to the second left-handed groove. The radially circumferential surface of each tooth of the band of teeth defines a face portion, the face portion having a periphery including first and second side edges that meet to form an apex oriented such that the two side edges open away from the direction of cutting rotation of the rotary cutting tool. A first side edge of the face portion is formed by the intersection of the face portion with a groove surface of the first right-handed groove, the first side edge defining the right cutting edge, and a second side edge of the face portion is formed by the intersection of the face portion with a first discontinuous groove surface portion of the first left-handed groove, the second side edge defining the left cutting edge. A first region of the face portion extending from the right cutting edge toward the interior region of the face portion is non-planar and defines a flank surface for the right cutting edge, and a second region of the face portion extending from the left cutting edge toward the interior region of the face portion is non-planar and defines a flank surface for the left cutting edge, the flank surfaces of the right cutting edge and the left cutting edge are not coplanar and meet at a transition feature.

[0014] The disclosed embodiments of the rotary cutting tool can be used to remove material from a workpiece by rotating the rotary cutting tool when mounted on a spindle of an apparatus for machining and removing material from a workpiece, for example, by contacting the first and second cutting edges with the workpiece. Exemplary workpieces are fiber-reinforced composite materials such as carbon fiber reinforced plastic (CRFP) or glass fiber reinforced plastic (GFRP).

[0015] An embodiment of the disclosed rotary cutting tool may include, for example, forming a tool body including a longitudinal central axis of rotation, the tool body being elongated and rotatable along the longitudinal central axis of rotation; and forming a plurality of major grooves and a plurality of minor grooves in a grooved cutting end of the tool body, each major groove including a major groove surface that projects radially inwardly from the tool body and extends continuously and spirally in an axial direction of the tool body; each minor groove including a minor groove surface that projects radially inwardly from the tool body and has a plurality of discontinuous groove surface portions that collectively extend spirally in the axial direction of the tool body; and two consecutive adjacent major grooves being arranged in a band. forming a plurality of major grooves and a plurality of minor grooves, each of the plurality of teeth being separated from one another by a plurality of teeth that are separated from one another by a first discontinuous minor groove surface of a first minor groove and a second discontinuous minor groove surface portion of a second minor groove, the first minor groove being continuously adjacent to the second minor groove; and forming a surface feature on a radial circumferential surface of each of the plurality of teeth arranged in a band, the surface feature defining a face portion having a periphery including first and second side edges that meet to form an apex oriented opposite the direction of cutting rotation of the rotary cutting tool. A first side edge of the face portion is formed by the intersection of the face portion with the groove surface of the first major groove, the first side edge defining the first cutting edge, a second side edge of the face portion is formed by the intersection of the face portion with the first discontinuous minor groove surface of the first minor groove, the second side edge defining the second cutting edge, a first region of the face portion extending from the first cutting edge toward the interior region of the face portion is non-planar and defines a clearance surface of the first cutting edge, and a second region of the face portion extending from the second cutting edge toward the interior region of the face portion is non-planar and defines a clearance surface of the second cutting edge.

[0016] Additional aspects, features, and advantages will be set forth in the description that follows, and in part will be obvious from the description, or may be learned by the practice of the invention. The objectives and other advantages of the disclosed rotary cutting tool are realized and attained by the structure particularly pointed out in the description and claims of the invention, as well as the accompanying drawings. However, other systems, methods, features, and advantages will be, or become, apparent to one skilled in the art upon examination of the following figures and detailed description. All such additional systems, methods, features, and advantages are intended to be included within this specification, be within the scope of the disclosure, and be protected by the following claims. Nothing in this section should be taken as a limitation on the scope of those claims. It is understood that both the foregoing general description and the following detailed description of the disclosed cutting tool are exemplary and explanatory and are intended to provide further explanation of the disclosed cutting tool as claimed.

[0017] The accompanying drawings, which are included to provide a further understanding of the invention, and which are incorporated in and constitute a part of this specification, illustrate implementations of the invention and, together with the description, serve to explain the principles of the disclosure. [Brief explanation of the drawings]

[0018] [Figure 1] 1A and 1B are isometric views from two different angles of a rotary cutting tool according to one embodiment of the disclosed cutting tool having continuous major flutes in a right-handed configuration and discontinuous minor flutes in a left-handed configuration. [Figure 2] 1A and 1B are isometric views from two different angles of a rotary cutting tool according to another embodiment of the disclosed cutting tool having continuous major flutes in a left-handed configuration and discontinuous minor flutes in a right-handed configuration. [Figure 3] FIG. 1 is a side plan view of a rotary cutting tool having continuous right-handed major flutes and discontinuous left-handed minor flutes. [Figure 4] FIG. 4 is an enlarged side plan view of the grooved cutting end P1 shown in FIG. 3. [Figure 5] 5 is an enlarged plan view of a portion of the band of teeth shown in part P2 in FIG. 4. FIG. [Figure 6] 6 is a cross-sectional view of the grooved cutting end shown at section VI-VI in FIG. 4. [Figure 7] FIG. 7 is an enlarged view of a portion P3 in FIG. [Figure 8] 8 is a cross-sectional view of the grooved cutting edge shown in section VIII-VIII of FIG. 4. [Figure 9] FIG. 10 is a cross-sectional view of the grooved cutting end in a plane perpendicular to the longitudinal axis of rotation showing the large groove feature. [Figure 10] FIG. 10 is a cross-sectional view of the fluted cutting end in a plane perpendicular to the longitudinal axis of rotation showing the small groove features. [Figure 11] FIG. 1 is an enlarged isometric perspective view of a portion of a fluted cutting end of a rotary cutting tool illustrating the relationship of cutting edges on two consecutive teeth in a tooth band. [Figure 12] FIG. 1 is an enlarged isometric perspective view of a portion of a fluted cutting end of a rotary cutting tool illustrating the relationship of transition features on two consecutive teeth in a band of teeth. [Figure 13A] FIG. 1 is an end view of an exemplary embodiment of a rotary cutting tool viewed along a longitudinal central axis of rotation having a central cutting end mill configuration. [Figure 13B] FIG. 1 is an end view of an exemplary embodiment of a rotary cutting tool viewed along a longitudinal central axis of rotation having a ball end mill configuration. [Figure 13C] FIG. 1 is an end view of an exemplary embodiment of a rotary cutting tool viewed along a longitudinal central axis of rotation having a drill point end mill configuration. [Figure 14] 1A-1D illustrate steps in a method of manufacturing one embodiment of the disclosed cutting tool. [Figure 15] 10A-10C are schematic diagrams illustrating aspects of grinding processes that can be used to form a surface profile on the radial circumferential surface of each tooth of a plurality of teeth arranged in a band and that define a surface portion. [Figure 16]10A-10C are schematic diagrams illustrating aspects of grinding processes that can be used to form a surface profile on the radial circumferential surface of each tooth of a plurality of teeth arranged in a band and that define a surface portion. [Figure 17] FIG. 1A illustrates a carbon reinforced composite workpiece machined with a rotary cutting tool according to one embodiment, and FIG. 1B illustrates a close-up of a portion of the machined edge. DETAILED DESCRIPTION OF THE INVENTION

[0019] Note that for clarity, not all instances of features shown in the figures are labeled with a reference symbol.

[0020] Throughout the drawings and detailed description, unless otherwise stated, reference symbols in the same drawing should be understood to refer to the same elements, features, and structures unless the context dictates otherwise. The relative size and depiction of these elements may be emphasized for clarity, illustration, and convenience. Furthermore, in some instances, reference symbols have not been applied to each instance of each feature in a particular drawing, so as to reduce the complexity of the reference symbol labeling and improve the overall understanding of the information conveyed in the figure. In such instances, the identity of the unlabeled feature is readily apparent from the description and other reference symbols.

[0021] In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, the use of like or identical reference numerals in different drawings typically indicates like or identical items, unless the context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made without departing from the spirit or scope of the subject matter presented herein. The sequence of process steps and / or operations described is exemplary, but the order of steps and / or operations is not limited to that set forth herein and may be varied as is well known in the art, except for steps and / or operations that necessarily occur in a particular order.

[0022] Those skilled in the art will understand that the components (e.g., operations), devices, objects, and accompanying discussion described herein are used as examples for conceptual clarity, and that various configuration modifications are contemplated. Consequently, as used herein, the specific representatives shown and the accompanying discussion are intended to be representative of their more general classes. In general, the use of any specific representative is intended to be representative of its class, and the exclusion of specific components (e.g., operations), devices, and objects should not be taken as limiting.

[0023] This application uses formal general headings for clarity of description. However, it should be understood that the general headings are for explanatory purposes and that different types of subject matter may be discussed throughout this application (e.g., devices / structures may be discussed under device / structure headings, and / or processes / operations may be discussed under structure / process headings, and / or a single topic description may span two or more topic headings). Therefore, the use of formal general headings is not intended to be limiting in any way.

[0024] The disclosed aspects, features, and advantages of the rotary cutting tool can be embodied in a rotary cutting tool in which the continuous major flutes are right-handed and the discontinuous minor flutes are left-handed, or in a rotary cutting tool in which the continuous major flutes are left-handed and the discontinuous minor flutes are right-handed. Regardless of symmetry, the major flutes provide chip evacuation and are for material removal, and the intersecting orientation of the major and minor flutes results in the cutting edge of the rotary cutting tool. The following description will focus on one embodiment in which the continuous major flutes are right-handed and the discontinuous minor flutes are left-handed, but it will be understood that corresponding aspects, features, functions, and advantages disclosed with respect to a rotary cutting tool with continuous right-handed major flutes and discontinuous left-handed minor flutes can be embodied in a rotary cutting tool with continuous left-handed major flutes and discontinuous right-handed minor flutes.

[0025] 1A and 1B are isometric views from two different angles of a rotary cutting tool according to one embodiment of the disclosed cutting tool having continuous major flutes in a right-handed configuration and discontinuous minor flutes in a left-handed configuration. The rotary cutting tool 100 includes a tool body 105 that is elongated and rotatable (R1) along a longitudinal central axis of rotation 110. The tool body 110 can optionally have one of a cylindrical, conical, or undulating shape. The rotary cutting tool 100 includes a fluted cutting end 112 and a shank portion 114. The shank portion 114 is axially opposite the fluted cutting end 112 (with respect to the longitudinal central axis of rotation 110). The fluted cutting end 112 includes a radially extending circumferential surface 120 and an end face 125. In some embodiments, the peripheral surface 120 extends axially rearward from the end face 125 along the longitudinal axis of rotation 110 to a location along the tool body 100 where the fluted cutting end 112 transitions directly into the shank portion 114. In other embodiments, one or more intermediate portions are interposed between the fluted cutting end 112 and the shank portion 114. At the axially opposite end of the tool 100 from the end face 125, the shank portion 114 may optionally have means for attaching the rotary cutting tool 100 (e.g., via a chuck or clamp) to a machining device such as a machine tool or computer numerically controlled (CNC) device.

[0026] A plurality of major grooves 130 and a plurality of minor grooves 135 are located on the fluted cutting end 112. Each major groove 130 includes a major groove surface 140 that projects radially inwardly from the tool body 105 (relative to the longitudinal axis of rotation 110) and that extends continuously and spirally in the axial direction of the tool body 105 (relative to the longitudinal axis of rotation 110). In some embodiments, the major groove surface 140 is continuous along at least a portion, e.g., a majority, of the helical length of the major groove 130. In other embodiments, the major groove surface 140 is continuous along the entire helical length of the major groove 130. Each minor groove 135 includes a minor groove surface 145 that projects radially inwardly from the tool body 105 (relative to the longitudinal axis of rotation 110). The plurality of discontinuous chamfer surface portions 150 collectively form the chamfer surface 145, and for any one chamfer 135, collectively extend helically in the axial direction of the tool body 105. For ease of visualization, by way of example, the chamfer 135 is identified by dashed lines connecting the discontinuous chamfer surface portions 150 of one chamfer surface 135a. In some embodiments, the chamfer surface 145 is discontinuous along at least a portion, e.g., a majority, of the helical length of the chamfer 135. In other embodiments, the chamfer surface 145 is continuous along the entire helical length of the chamfer 135.

[0027] The number of major grooves 130 and the number of minor grooves 135 in the rotary cutting tool 100 can vary. In exemplary embodiments, the total number of major grooves 130 in the plurality of major grooves is between 2 and 6, alternatively 4, and the total number of minor grooves 135 in the plurality of minor grooves is between 4 and 12, alternatively 8. In some embodiments, the total number of major grooves 130 is less than the total number of minor grooves 135. In other embodiments, the total number of major grooves 130 is the same as the total number of minor grooves 135.

[0028] The exemplary embodiment shown in Figures 1A and 1B is a right-handed tool (meaning that the tool 100 rotates counterclockwise to make a cut (indicated by direction R1 in Figures 1A and 1B) when viewed from end face 125 along the longitudinal central axis of rotation 110), although other embodiments may be left-handed tools (as discussed further herein).

[0029] 2A and 2B are isometric views from two different angles of a rotary cutting tool according to another embodiment of the disclosed cutting tool, having continuous major flutes in a left-handed configuration and discontinuous minor flutes in a right-handed configuration. The features, geometry, functions, and advantages of the rotary cutting tool 200 in FIGS. 2A and 2B correspond to the similar features, geometry, and functions of the rotary cutting tool 100 in FIGS. 1A and 1B, except for the different symmetries of the major flutes and minor flutes and the concomitant different rotational directions for machining. Thus, the rotary cutting tool 200 includes a tool body 205 that is elongated and rotatable (R2) along a longitudinal central axis of rotation 210. The rotary cutting tool 200 has a fluted cutting end 212 and a shank portion 214. The shank portion 214 is axially opposite the fluted cutting end 212 (relative to the longitudinal central axis of rotation 210). The fluted cutting end 212 includes a radially circumferential surface 220 and an end face 225. In some embodiments, the peripheral surface 220 extends axially rearward from an end surface 225 along the longitudinal axis of rotation 210 to a location along the tool body 200 where the fluted cutting end 212 transitions directly into the shank portion 214. In other embodiments, one or more intermediate portions are interposed between the fluted cutting end 212 and the shank portion 214. A plurality of major grooves 230 and a plurality of minor grooves 235 are located on the fluted cutting end 212. Each major groove 230 includes a major groove surface 240 that projects radially inwardly of the tool body 205 (relative to the longitudinal axis of rotation 210) and extends continuously and spirally in the axial direction of the tool body 205 (relative to the longitudinal axis of rotation 210). Each minor groove 235 includes a minor groove surface 245 that projects radially inwardly of the tool body 205 (relative to the longitudinal axis of rotation 210). The groove surfaces 245 collectively form the groove surface 245 and in any one groove 235 include a plurality of discontinuous groove surface portions 250 that collectively extend spirally in the axial direction of the tool body 205 .

[0030] FIG. 3 is a side plan view of a rotary cutting tool 100 having continuous right-handed major flutes 130 and discontinuous left-handed minor flutes 135, and FIG. 4 is an enlarged side plan view of the fluteed cutting end P1 shown in FIG. 3. In FIGS. 3 and 4, two consecutively adjacent major flutes, such as major flutes 130a and 130b, are separated from one another by a plurality of teeth 305 arranged in a band 300. For ease of viewing, as an example, the teeth 305 in band 300a are identified by dashed lines connecting the teeth 305 in one band 300a. The individual teeth 305 in the plurality of teeth 305 in band 300 are separated from one another by a first discontinuous minor flute surface portion 150a of a first minor flute 135 and a second discontinuous minor flute surface portion 150b of a second minor flute 135 (the first minor flute 135 is continuously adjacent to the second minor flute 135).

[0031] FIG. 5 is an enlarged plan view of a portion of the band of teeth shown at section P2 in FIG. 4 . The radial periphery of the tooth 305 is shown in FIG. 5 . Also shown in FIG. 5 is the region of the cutting tool 100 immediately adjacent to the tooth 305, including the major groove surface 140 (from two consecutive right-handed major grooves 130) and the first discontinuous minor groove surface portion 150 a of the first minor groove 135 and the second discontinuous minor groove surface portion 150 b of the second minor groove 135 (the first minor groove 135 is consecutively adjacent to the second minor groove 135). The radial periphery of the tooth defines a face portion 310 having a periphery 320. The periphery 320 includes a first side edge 325 formed by the intersection of the face portion 310 with the groove surface 140 of the first major groove 130. The first side edge 325 defines a first cutting edge. The peripheral portion 320 also includes a second side edge 330 formed by the intersection of the face portion 310 and the discontinuous chamfer surface portion 150a of the chamfer 135. The second side edge 330 defines a second cutting edge. The first side edge 325 and the second side edge 330 meet such that the two side edges 325, 330 form an apex 335 that is oriented to open away from the cutting rotation direction (R1) of the rotary cutting tool 100. Given this arrangement, the apex 335 is a leading edge (in the cutting rotation direction R1 of the rotary cutting tool) during cutting.

[0032] The symmetry of the cutting edge depends on the symmetry of the rotary cutting tool. For example, in a right-handed rotary cutting tool, the first side edge defines the right cutting edge and the second side edge defines the left cutting edge. For example, in a left-handed rotary cutting tool, the first side edge defines the left cutting edge and the second side edge defines the right cutting edge.

[0033] A first region 340 of the face portion 310 extends from the first cutting edge (defined by the first side edge 325) toward an interior region of the face portion 310. A second region 350 of the face portion 310 extends from the second cutting edge (defined by the second side edge 330) toward an interior region of the face portion. Both the first region 340 and the second region 350 are non-planar and each define a flank face of their corresponding cutting edge, i.e., the first region 340 defines the flank face of the first cutting edge and the second region 350 defines the flank face of the second cutting edge.

[0034] FIG. 6 is a cross-sectional view of the fluted cutting edge shown at cut VI-VI in FIG. 4, and FIG. 7 is an enlarged view of section P3 in FIG. 6. The cross-sectional view in FIG. 6 is a plane parallel to and containing the longitudinal central axis of rotation 110. Note also that FIG. 7 corresponds to the cross-sectional view of the tooth at section P2 at cut VI-VI in FIG. 4 and the cross-sectional view of the tooth at cut VII-VII in FIG. 5. FIG. 7 further illustrates the shapes of first region 340 and second region 350, which function as clearance surfaces for the first cutting edge (defined by first side edge 325) and the second cutting edge (defined by second side edge 330). As can be seen in FIG. 7, both first region 340 and second region 350 are each non-planar. In some embodiments, first region 340 (defining the clearance surface of the first cutting edge) includes a curved surface having a first radius (r1). In another aspect, the second region 350 (defining the flank of the second cutting edge) includes a curved surface having a second radius (r2). In one embodiment, the first region 340 (defining the flank of the first cutting edge) includes a curved surface having a first radius (r1) and the second region 350 (defining the flank of the second cutting edge) includes a curved surface having a second radius (r2), and the lengths of the first radius (r1) and the second radius (r2) are the same. In a second embodiment, the first region 340 (defining the flank of the first cutting edge) includes a curved surface having a first radius (r1) and the second region 350 (defining the flank of the second cutting edge) includes a curved surface having a second radius (r2), and the lengths of the first radius (r1) and the second radius (r2) are different.

[0035] In other alternative embodiments, the shapes of the first region 340 and the second region 350 can be convex or can have varying or multiple convexities. For example, in some embodiments, the first region 340 (defining the flank of the first cutting edge) includes a surface having multiple convex regions. In other embodiments, the second region 350 (defining the flank of the second cutting edge) includes a surface having multiple convex regions. The convexities associated with the first region 340 and the second region 350 can be the same or different between the two regions. Furthermore, these convexities can be simple, such as a circle or an ellipse or a curve associated with a parabola, or can be complex, such as associated with a cubic (or higher) polynomial function.

[0036] In yet other alternative embodiments, the shape of first region 340 and second region 350 may vary from a curve or may be a series of short connected planes that approximate a curve.

[0037] The flanks of the first cutting edge and the flanks of the second cutting edge meet at a transition feature 360. The transition feature 360 ​​may be a feature formed by the intersection of two non-coplanar flanks 340, 350, e.g., a line, which may be visible as a line or may be an imaginary line, resulting from the intersection of the two non-coplanar flanks. As such, the feature may be formed by an angle between the two non-coplanar flanks 340, 350. Alternatively, the transition feature 360 ​​may be a radiused surface connecting the two angled, non-coplanar flanks 340, 350. In another alternative, the transition feature 360 ​​may be a plane, such as a land, connecting the two angled, non-coplanar flanks 340, 350, and the transition from the plane to each of the two angled, non-coplanar flanks 340, 350 may itself be angled or radiused.

[0038] 5 depicts the transition feature 360 ​​as straight, the relief feature 360 ​​may have alternative shapes, such as curved or sawtooth. Additionally, as shown in FIG. 5, the relief feature bisects the apex angle (φ). However, in other embodiments, the transition feature 360 ​​may not bisect but may be oriented (over its length extending from the apex 335) to be closer to the first cutting edge (defined by the first side edge 325) or closer to the second cutting edge (defined by the second side edge 330). In exemplary embodiments, the apex angle (φ) has a value greater than or equal to 40 degrees and less than or equal to 90 degrees, alternatively greater than or equal to 45 degrees and less than or equal to 70 degrees or greater than or equal to 55 degrees and less than or equal to 65 degrees, or equal to 60±1 degree.

[0039] In the exemplary embodiment, the first cutting edge (defined by the first side edge 325), the second cutting edge (defined by the second side edge 330), and the apex 335 lie on the surface of an imaginary cylinder 400 having a centroidal axis that coincides with the longitudinal centroidal axis of rotation 110. It can be seen from FIGS. 6 and 7 that the first cutting edge (defined by the first side edge 325) and the second cutting edge (defined by the second side edge 330) lie on the surface of the imaginary cylinder 400. As seen in FIGS. 6 and 7, the first cutting edge (defined by the first side edge 325) coincides with and lies on the surface of the imaginary cylinder 400. Similarly, the second cutting edge (defined by the second side edge 330) coincides with and lies on the surface of the imaginary cylinder 400. In one embodiment, first region 340 (defining the clearance of the first cutting edge) and second region 350 (defining the clearance of the second cutting edge) radiate inward (relative to the longitudinal axis of rotation 110) of the surface of imaginary cylinder 400. In such an arrangement, trailing apex 370 may coincide with and lie on the surface of imaginary cylinder 400 (see trailing apex 370 in FIG. 8 lying on imaginary cylinder 400). In another embodiment, all other portions of face portion 310, i.e., all portions other than first cutting edge (defined by first side edge 325), second cutting edge (defined by second side edge 330), and apex 335, radiate inward (relative to the longitudinal axis of rotation 110) of the surface of imaginary cylinder 400. In this embodiment, "all other portions" includes rear apex 370 and other portions of periphery 320 of face portion 310, such as the rear of first side edge 380 and the rear of second side edge 385 (for quadrilateral face portion 310 as shown in FIG. 5). In both embodiments, these surfaces radiating inward of imaginary cylinder 400 provide clearance for the first and second cutting edges in the cutting rotation direction (R) of rotary cutting tool 100.

[0040] 5, the periphery 320 of the face portion 310 has a quadrilateral shape. In some embodiments, the quadrilateral is a parallelogram, while in other embodiments, the quadrilateral is a rhombus.

[0041] Returning to Figure 8, a cross-sectional view of the grooved cutting end shown at section VIII-VIII in Figure 4, the spatial relationship between the periphery 320 of the surface portion 310 and the surface of an imaginary cylinder 400 is shown. The view of Figure 8 shows a cross-section plane perpendicular to the longitudinal central axis of rotation 110 and intersecting at least one tooth 305 of the plurality of teeth arranged in band 300. In this view, the intersection of the plane with the surface portion 310 forms a chord 410 with the periphery of the imaginary cylinder 400. The chord 410 has endpoints 415 and 420. The arc (θ) of the periphery of the imaginary cylinder 400 between endpoints 415, 420 of the chord 410 is greater than or equal to 30 degrees and less than or equal to 45 degrees, alternatively greater than or equal to 30 degrees and less than or equal to 35 degrees, or 31±1 degrees.

[0042] Also, referring to Figure 8, both the major groove 130 and the minor groove 135 are visible. In the cross section in Figure 8, it is readily apparent that the arc length 440 of the major groove 130 exceeds the arc length 445 of the minor groove 135. In one embodiment, multiple minor grooves are visible through the opening of the major groove, visually confirming that the arc length 440 of the major groove 130 exceeds the arc length 445 of the minor groove 135. In one embodiment, the arc length 445 of the minor groove 135 exceeds (0.5 x the arc length 440 of the major groove 130). In another embodiment, the arc length 440 of the major groove 130 is a non-integer multiple of the arc length 445 of the minor groove 135, where the non-integer multiple is greater than 1 and less than 5, alternatively greater than 1 and less than 4, or greater than 1 and less than 3.

[0043] With further reference to the cross-section shown in Figure 8, the peripheral rake angle associated with each of the major flutes 130 and minor flutes 135 can be seen. The peripheral rake angle is the angle between the flute rake face and the radius measured in a plane perpendicular to the longitudinal central axis of rotation 110. As shown in Figure 8, each major flute 130 has a positive peripheral rake angle (γ) and each minor flute 135 has a positive peripheral rake angle (ε). In the exemplary embodiment, the positive peripheral rake angle (γ) is 9° < γ < 11°, or alternatively, γ = 10°, and the positive peripheral rake angle (ε) is 9° < ε < 11°, or alternatively, ε = 10°.

[0044] Overall, in the exemplary embodiment of the rotary cutting tool, the teeth 305 of each band 300 have a geometric shape that is identical in at least some aspects, and in some embodiments, identical in all aspects. In some aspects, at least all of the teeth 305 in one of the plurality of bands 300 have the same geometric shape, but the geometric shape of the teeth 305 in one band 300 can vary from the geometric shape of the teeth 305 in a second band 300. In other aspects, at least all of the teeth 305 in one of the plurality of bands 300 have the same geometric shape, but the geometric shape of the teeth 305 in one band 300 can vary from the geometric shape of the teeth 305 in a second band 300. In still other aspects, the face portions 310 of all of the teeth 305 in one of the plurality of bands 300 have the same geometric shape.

[0045] Both the major groove 130 and the minor groove 135 have a helical centerline, which is an imaginary line located at the radially innermost surface of the corresponding groove. Figure 4 shows an example of a helical centerline 500 for a major groove 130 and a helical centerline 510 for a minor groove 135, and Figure 6 shows the location at the radially innermost surface of the major groove 130 where the helical centerline 500 is located. The helical centerline is representative of the helical shape of the corresponding groove, and the angle formed between the helical centerline and an imaginary plane containing the longitudinal central axis of rotation 110 represents the helix angle of the groove. For example, the angle formed between the helical centerline 500 of a major groove 130 and an imaginary plane containing the longitudinal central axis of rotation 110 represents the helical angle (α) of the major groove 130, and the angle formed between the helical centerline 510 of a minor groove 135 and an imaginary plane containing the longitudinal central axis of rotation 110 represents the helical angle (β) of the minor groove 135. In an exemplary embodiment, the helical angle (α) of each major groove 130 has an absolute value of 45°≦|α|≦70°, or alternatively, 59°≦|α|≦61°, and the helical angle (β) of each minor groove 135 has an absolute value of 45°≦|β|≦70°, or alternatively, 59°≦|β|≦61°. In one aspect, the absolute value of the helical angle (α) of each major groove 130 and the absolute value of the helical angle (β) of each minor groove 135 are the same. In another embodiment, the absolute value of the helix angle (α) of each major groove 130 and the absolute value of the helix angle (β) of each minor groove 135 are different.

[0046] In a further embodiment, the helical centerlines 500 of each of two consecutively adjacent large grooves 130 are spaced apart at a constant distance along the longitudinal length of the grooved cutting end 112. An example of a separation distance D1 between the helical centerlines 500a, 500b of two consecutively adjacent large grooves 130a, 130b is shown in Figure 6. In the illustrated embodiment, the separation distance D1 is a function of the tool diameter, the spiral lead, and the number of large grooves.

[0047] 9 is a cross-sectional view of the fluted cutting end 112 taken along a plane perpendicular to the longitudinal axis of rotation 110, illustrating the characteristics of the large grooves 130. FIG. 9 shows the distribution of the large grooves 130 around the tool's circumference, as well as the cross-sectional shape of the large groove surface 140. The tool has a first core diameter defined by an imaginary circle 520 centered on the longitudinal axis of rotation 110 and having an outer periphery connecting the radially innermost surfaces of the large grooves 130, i.e., the locations on the large groove surface 140 where the helical centerlines 500 are located. The difference between the length of the radius (r3) of the surface of the imaginary cylinder 400 and the length of the radius (r4) of the first core defines the radial depth of the large grooves 130.

[0048] Figure 10 is a cross-sectional view of the fluted cutting end 112 in a plane perpendicular to the longitudinal axis of rotation 110, showing the characteristics of the flutes 135. Figure 10 schematically illustrates the distribution of the flutes 135 around the periphery of the tool and the cross-sectional shape of the flute surface 145. The tool has a second core diameter defined by an imaginary circle 530 centered on the longitudinal axis of rotation 110 and having an outer periphery connecting the radially innermost surfaces of the flutes 135, i.e., the locations on the flute surface 140 where the helical centerlines 510 are located. The difference between the length of the radius (r3) of the surface of the imaginary cylinder 400 and the length of the radius (r5) of the second core defines the radial depth of the flutes 135.

[0049] In the illustrated embodiment, the value of r4 is 60% of the value of r3, and the value of r5 is 80% of the value of r3.

[0050] In one embodiment of the rotary cutting tool 100, the large grooves 130 have a first core diameter that is less than the second core diameter of the small grooves 135. In other words, the length of the first core radius (r4) of the large grooves 130 is less than the length of the second core radius (r5) of the small grooves 135. In another embodiment of the rotary cutting tool 100, the radial depth of the large grooves 130 is greater than the radial depth of the small grooves 135.

[0051] Also visible in FIGS. 9 and 10 is the positive peripheral rake angle (γ) of the major flutes 130 and the positive peripheral rake angle (ε) of the minor flutes 135.

[0052] FIG. 11 is an enlarged isometric perspective view of the grooved cutting end 112 of the rotary cutting tool 100, illustrating the relationship of cutting edges on two consecutive teeth 305 in a tooth band 300. FIG. 11 is viewed perpendicular to a plane containing the longitudinal central axis of rotation 110. In the tooth band 300 shown in FIG. 11, a first tooth 305a is separated from a second tooth 305b by a groove 135. In the embodiment shown, the first tooth 305a is the leading tooth (relative to the second tooth 305b in the cutting rotation direction (R1)). The first tooth 305a has a first cutting edge (defined by a first side edge 325a) and a second cutting edge (defined by a second side edge 330a) that meet at an apex 335a, and the second tooth 305b has a first cutting edge (defined by a first side edge 325b) and a second cutting edge (defined by a second side edge 330b) that meet at an apex 335b. Figure 11 also shows the overlap between the first tooth 305a, which is the leading tooth, and the second tooth 305b, which is the trailing tooth (in the cutting rotation direction (R)). At least a portion of the first cutting edge (defined by first side edge 325a) of the first tooth 305a axially overlaps (relative to the axial direction of the longitudinal rotational centerline axis 110) at least a portion of the second cutting edge (defined by first side edge 330b) of the second tooth 305b. In FIG. 11 , the overlap is shown as overlap (Δ). In certain embodiments, the rearward portion 580 of the first cutting edge (defined by first side edge 325a) of the first tooth 305a axially overlaps the rearward portion 585 of the second cutting edge (defined by first side edge 330b) of the second tooth 305b. In the illustrated embodiment, the overlap (Δ) is between 6% and 10% of the slope (P). When viewed in a plane perpendicular to the longitudinal rotational axis and intersecting two consecutive adjacent teeth of the band-like teeth, i.e., the plane located at the location of the overlap (Δ), a portion of the first cutting edge (defined by the first side edge 325a) of the first tooth 305a is in front of a portion of the second cutting edge (defined by the first side edge 330b) of the second tooth 305b relative to the cutting rotation direction (R).The overlap (Δ) ensures that there are no gaps in the effective cutting edge of tool 100 formed by teeth 305 in tooth band 300 as tool 100 rotates in the cutting rotation direction (R1) during machining of the workpiece and provides a smooth finish on the workpiece.

[0053] FIG. 12 is an enlarged, isometric perspective view of the fluted cutting end 112 of the rotary cutting tool 100 illustrating the relationship of the transition features 360 of two consecutive teeth 305 in a tooth band 300. FIG. 12 is a view similar to that shown in FIG. 11. In the tooth band 300 shown in FIG. 12, the distance (D2) (determined parallel to the longitudinal central axis of rotation 110) between the transition features 360 of adjacent teeth 305 on one tooth band 300 defines the tooth slope (P). Additionally, the longest distance (D3) (determined parallel to the longitudinal central axis of rotation 110) between the first cutting edge (defined by the first side edge 325) and the second cutting edge (defined by the second side edge 330) of one face portion 310 of the tooth 305 defines the cutting width (W). In the illustrated embodiment, the cutting width (W) exceeds the slope (P). When the slope (P) and width (W) are constant for the teeth 305 in the tooth band 300, the width (W) exceeding the slope (P) ensures that there are no gaps in the effective cutting edge of the tool 100 formed by the teeth 305 in the tooth band 300 as the tool 100 rotates in the cutting rotation direction (R1) during machining of a workpiece.

[0054] The end face 125 of the rotary cutting tool 100 can have any of a variety of shapes known in the art of end mills. For example, as shown in FIG. 13A, which is a view of the end face as seen along the longitudinal central axis of rotation 110, the end face 125 can have a center-cutting end mill configuration. In a center-cutting end mill configuration, the end face 125 in side plan view is flat (see also FIGS. 3-4 and 6) and includes an end cutting edge 600. The portion of the end cutting edge 600 that coincides with the flat end face 125 is radially straight (see FIG. 13A).

[0055] In another example, the end face 125 can have a ball end mill configuration with a curved cutting edge 610, as shown in FIG. 13B, which is a view of the end face as seen along the longitudinal axis of rotation 110.

[0056] In another example, as shown in FIG. 13C, which is a view of the end face as seen along the longitudinal central axis of rotation 110, end face 125 can have a drill point end mill having a first axially angled cutting edge 620a and a second axially angled cutting edge 620b (typically straight cutting edges) that form an included drill point 625 angle and two offset angled cutting edges 630a and 630b (typically straight cutting edges).

[0057] However, the features, improvements, methods, processes, and other technical details disclosed herein are also applicable to other kinds and types of rotary cutting tools, such as other types of end mills, face mills, side mills, and drill points having cutting point geometries.

[0058] The rotary cutting tool optionally includes a coating on the surface of the fluted cutting end 112. In one embodiment, the coating is present on all of the surfaces of the fluted cutting end 112. In other embodiments, the coating is present on a portion of the surface of the groove, cutting edge, face portion, or a combination thereof. In still further embodiments, the coating is present on a portion of the fluted cutting end 112 that includes the major groove surface 140, the minor groove surface 145, the first cutting edge (defined by the first side edge 325), the second cutting edge (defined by the second side edge 330), the first region 340 (defining the clearance face of the first cutting edge), the second region 350 (defining the clearance face of the second cutting edge), or a combination of these surfaces. Furthermore, in some embodiments, the coating is present on the surface along the entire axial length of the fluted cutting end 112, while in other embodiments, the coating is present on the surface along a portion of the axial length of the fluted cutting end 112, e.g., the first 50%, alternatively the first 25%, of the axial length of the fluted cutting end 112 rearward from the end face 125. In each of the above, the end face 125 may or may not be coated.

[0059] The coating can be any suitable coating known in the art of cutting tools. For example, the coating can be a chemical vapor deposition (CVD) coating. One example of a suitable CVD coating is polycrystalline diamond (PCD). In another example, the coating can be a physical vapor deposition (PVD) coating. Examples of suitable physical vapor deposition coatings include diamond-like carbon (DLC), graphite, Ti(Al,N), Ti(C,N), Al(Ti,N), and Al(Cr,N). Both stoichiometric and non-stoichiometric Ti(Al,N), Ti(C,N), Al(Ti,N), and Al(Cr,N) can be used as coatings. Typically, the coating is 100 nm to 3 microns thick, alternatively 1 micron to 2 microns thick.

[0060] Embodiments of the rotary cutting tool 100 may optionally have internal passages for delivery of coolant (liquid or gas) to the cutting zone. When present, such internal passages may extend longitudinally inwardly and, if desired, spirally tapered to extend from the shank portion 114 to an outlet exposed at the surface of the fluted cutting end 112, typically the flute surfaces 140, 145, and / or the end face 125.

[0061] Additionally, the features disclosed, described, and illustrated in the figures herein are typically implemented in solid rotary cutting tools in which the flutes and teeth (and associated features, including cutting edge and face portion geometries) are integrally formed with the tool body. However, the flutes and teeth (and associated features, including cutting edge and face portion geometries) may also be implemented in tools that utilize removable cutting inserts.

[0062] FIG. 14 illustrates steps in a method of manufacturing one embodiment of the disclosed cutting tool. The method 700 shown in FIG. 14 includes forming 710 a tool body 105 including a longitudinal central axis of rotation 110. As disclosed herein, the tool body 105 is elongated and rotatable along the longitudinal central axis of rotation 110. In some aspects, the tool body blank is formed as a solid body of a hard material, such as titanium carbide (TiC) or tantalum carbide (TaC), with or without carbide particles, by solidifying a hard material, such as tungsten cemented carbide (WC) or tungsten carbide-cobalt (WC-Co). Other materials, such as tool steel, high-speed steel, and ceramics, can be used for the tool body.

[0063] After forming the blank of the tool body 105, the plurality of major grooves 130 and the plurality of minor grooves 135 are formed 720 in the grooved cutting end 112 of the blank. In some embodiments of the method 700, the solid blank can be formed as a rod, in which case the plurality of major grooves 130 and the plurality of minor grooves 135 are formed in the grooved cutting end 112 of the tool body 105 by a suitable material removal means, for example, grinding and / or polishing. It is also contemplated that additional manufacturing methods may be applied to produce a rough form of the tool that is then finally machined into its final form, such as by grinding and / or polishing.

[0064] Grinding can be by any suitable technique, such as CBN, aluminum oxide, and diamond grinding wheels, and is typically assisted by computer-controlled positioning and translation devices. Machining removes material from the helical flutes (both major and minor flutes) to produce teeth having selected values ​​of helix angle (α) and helix angle (β), and selected values ​​of apex angle (φ) and rake angles (γ) and (ε), all within the ranges disclosed herein (and taking into account manufacturing tolerances).

[0065] For removable cutting insert rotary cutting tools, a tool body blank is made by any suitable technique, including, for example, those discussed above for solid rotary cutting tools. The blank has a generally elongated tool body configuration and includes a spirally extending groove. Seat pockets for the removable, indexable cutting inserts are formed in the band-like teeth. The seat pockets are correspondingly sized, spaced, and oriented to accommodate the subject removable, indexable cutting inserts in a desired orientation relative to various relevant features and surfaces of the tooth, including the apex 335 and first and second side edges 325, 330, which meet to form the features of face portion 310, all formed on the removable, indexable cutting insert.

[0066] It is also contemplated that a rotary cutting tool may be fitted into a seat pocket on the rotary cutting tool after realizing a combination of features integrally formed with the tool body and features formed on a removable, indexable cutting insert.

[0067] In other embodiments of method 700, the solid shape of the tool body 105 can be directly formed (at least in a rough form) using powder metallurgy techniques, where the plurality of large grooves 130 and the plurality of small grooves 135 (having one or more of the various features disclosed herein) are formed in the grooved cutting end 112 of the tool body 105 by a shaping process utilized in the powder metallurgy process. In some cases, the grooves formed using powder metallurgy techniques are then finished by grinding or other techniques to obtain the final dimensions and surface finish.

[0068] After the groove contour of the tool body is formed, a surface profile is formed 730 on the radial circumferential surface of each tooth 305 of the plurality of teeth arranged in band 300. The surface profile defines a face portion 310 having one or more of the various features disclosed herein.

[0069] In one embodiment, the surface profile is formed by grinding. FIGS. 15 and 16 schematically illustrate aspects of a grinding process that can be used to form a surface profile on the radially circumferential surface of each tooth of a plurality of teeth arranged in a band. As shown schematically in FIG. 15 , a grinding wheel 800 having a grinding form 805 makes rolling contact with the surface to be ground on the radially circumferential surface of the tooth. The grinding form, the tool body, or both can be rotated to affect the rolling contact. The grinding form 805 has a cross-sectional shape that is a concave of the desired surface profile of the first region 340 of the face portion 310 and the second region 350 of the face portion 310, which define the clearance faces of each of the first and second cutting edges. In the illustrated example, the grinding form 805 has a cross-sectional shape that includes a first concave surface 810 and a second concave surface 820 that intersect at a ridge 830. During the grinding operation, ridges 830 typically align with apexes 335 of quadrilateral face portion 310. Because ridges 830 form transition features 360, grinding is performed such that transition features 360 are formed in the desired location and orientation relative to features of face portion 310, such as side edges 325, 330, 380, 385, and trailing apex 370.

[0070] 16 is a side cross-sectional view of face portion 310 of tooth 305, showing the tooth's leading apex 335, transition feature 360, trailing apex 370, and cutting edge. As can be seen in FIG. 16, face portion 310 is at a peripheral clearance angle (ψ) of 15±1 degrees.

[0071] Method 700 also optionally includes coating the surface of fluted cutting edge 120 with a chemical vapor deposition (CVD) coating or a physical vapor deposition (PVD) coating as disclosed herein.

[0072] The disclosed rotary cutting tool embodiments can be used in machining operations to remove material from a workpiece. For example, the disclosed rotary cutting tool embodiments can be mounted to a spindle of a machining device, such as a machine tool or a computer numerically controlled (CNC) device. Typically, the shank portion 114 is clamped or mounted to the spindle for axial rotation of the rotary cutting tool 100 about a longitudinal central axis of rotation 110. The mounted rotary cutting tool 100 is then rotated, and workpiece material is removed by contacting the cutting edges, i.e., the first cutting edge (defined by the first side edge 325) and the second cutting edge (defined by the second side edge 330), with the workpiece. Typically, the apex 335 makes initial contact with the workpiece during machining. Alternatively, a rotary cutting tool having the above-described radial cutting edge (and related features including one or more of the tooth pattern and rake face surface) can be mounted in a stationary position in an apparatus for machining, and a workpiece can be positioned, moved, and / or rotated and contacted relative to the radial cutting edge to remove material from the workpiece. The workpiece can be a metallic material, which can be ferrous or non-ferrous, a metal alloy material, a natural or synthetic material, or a composite material of two or more different materials. In a specific embodiment, the workpiece is a fiber-reinforced composite material such as carbon fiber reinforced plastic (CRFP) or glass fiber reinforced plastic (GFRP). The geometry of the helix angle (α, β), peripheral rake angle (γ, ε), arc (θ), and apex angle (φ) will typically vary based at least in part on the nature of the material being machined, resulting in variations in tooth geometry. These geometries are adjustable based on, for example, the number of fiber layers, fiber orientation, and stacked combinations of layers and materials, such as laminates of aluminum or aramid outer layers.

[0073] By way of example, embodiments of the disclosed rotary cutting tool can be used in machining operations to remove material from a carbon-reinforced composite workpiece. FIG. 17A shows a carbon fiber reinforced plastic (CRFP) workpiece 700 machined with a rotary cutting tool according to disclosed embodiments. The workpiece 700 is machined by machining an edge 705 with a center-cutting end mill having right-handed major flutes and left-handed minor flutes. FIG. 17B shows an enlarged view of a portion of the machined edge 705, corresponding to portion P3 in FIG. 17A. As can be seen in the enlarged view, no delamination or fracture of layers, nor fiber pullout or unsheared fibers are evident.

[0074] EXAMPLE: The following information in Table 1 describes an embodiment of a manufactured cutting tool consistent with embodiments disclosed herein. TIFF0007727657000001.tif113170

[0075] As noted above, the disclosed rotary cutting tool can be embodied in a rotary cutting tool in which the continuous major flutes are right-handed and the discontinuous minor flutes are left-handed, or in a rotary cutting tool in which the continuous major flutes are left-handed and the discontinuous minor flutes are right-handed. In embodiments in which the continuous major flutes are right-handed and the discontinuous minor flutes are left-handed (see, e.g., FIGS. 1A and 1B), the major flutes are right-handed flutes, the minor flutes are left-handed, the first cutting edge is a right-handed cutting edge, and the second cutting edge is a left-handed cutting edge. In embodiments in which the continuous major flutes are left-handed and the discontinuous minor flutes are right-handed (see, e.g., FIGS. 2A and 2B), the major flutes are left-handed flutes, the minor flutes are right-handed, the first cutting edge is a left-handed cutting edge, and the second cutting edge is a right-handed cutting edge. All of the above features disclosed with respect to embodiments of rotary cutting tools having continuous right-handed major flutes and discontinuous left-handed minor flutes may be present alone or in combination in embodiments of rotary cutting tools having continuous left-handed major flutes and discontinuous right-handed minor flutes.

[0076] While the present invention has been described in connection with this embodiment, it will be understood by those skilled in the art that additions, deletions, modifications, and substitutions not specifically described may be made therein without departing from the spirit and scope of the invention as defined in the appended claims.

[0077] For the use of substantially all plural and / or singular terms herein, those skilled in the art can convert from plural to singular and / or from singular to plural as appropriate to the situation and / or application. The various singular / plural permutations are not specifically indicated herein for the sake of clarity.

[0078] The subject matter described herein often illustrates various components that are contained within or coupled to various other components. It should be understood that any such illustrated architectures are merely exemplary, and that in fact, many other architectures that achieve the same functionality may be implemented. In a conceptual sense, any arrangement of components that achieve the same functionality is effectively “associated” such that the desired functionality is achieved. Thus, any two components herein that combine to achieve a particular function can be viewed as being “associated” with one another such that the desired functionality is achieved, regardless of the architecture or intermediate components. Similarly, any two components so associated can also be viewed as being “operably coupled” or “operably coupled” to one another to achieve the desired functionality, and any two components so associateable can also be viewed as being “operably couplable” to one another to achieve the desired functionality. Examples of operably coupleable include, but are not limited to, physically matable and / or physically interacting components, and / or wirelessly interactable and / or wirelessly interacting components, and / or logically interacting and / or logically interacting components.

[0079] In some instances, one or more components may be referred to herein as being "configured to," "configurable to," "operable to," "adapted to," "capable to," "compatible to," etc. Those skilled in the art will understand that such terms (e.g., "configured to") can generally encompass active and / or inactive and / or standby components unless the context requires otherwise.

[0080] While particular embodiments of the present subject matter described herein have been shown and described, it will be apparent to those skilled in the art that, based on the teachings herein, changes and modifications may be made without departing from the subject matter described herein and its broader aspects, and therefore, the appended claims are intended to encompass within their scope all such changes and modifications as are within the true spirit and scope of the subject matter described herein. In general, those skilled in the art will understand that the terms used herein, and particularly in the appended claims (e.g., the body of the appended claims), are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). If a specific number recitation is intended in the introduced claim, such intention will be explicitly stated in the claim, and those skilled in the art will further understand that the absence of such recitation indicates that such intention does not exist. For example, as an aid to understanding, the following appended claims may contain the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be interpreted as suggesting that introducing a claim recitation with the indefinite article "a" or "an" limits any particular claim containing such introduced claim recitation to claims containing only one such recitation, even when the same claim contains the introductory phrases "one or more" or "at least one" and an indefinite article such as "a" or "an" (e.g., "a" and / or "an" should typically be interpreted to mean "at least one" or "one or more"). The same applies to the use of definite articles used to introduce claim recitations.Furthermore, even when a specific number is explicitly recited in an introduced claim recitation, those skilled in the art will understand that such a recitation should typically be interpreted to mean at least the recited number (e.g., the mere recitation of "two recitations" without other modifiers typically means at least two recitations, or two or more recitations). Furthermore, in instances where a conventional expression similar to "at least one of A, B, and C, etc." is used, such syntax is generally intended in the sense that those skilled in the art would understand the conventional expression (e.g., "a system having at least one of A, B, and C" includes, but is not limited to, systems having only A, only B, only C, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). In instances where conventional language similar to "at least one of A, B, or C, etc." is used, such syntax is generally intended in the sense that one of ordinary skill in the art would understand the conventional language (e.g., "a system having at least one of A, B, or C" includes, but is not limited to, systems having A only, B only, C only, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). Those of ordinary skill in the art will further understand that disjunctions and / or phrases presenting two or more alternative terms should typically be understood to contemplate the possibility of including one of the terms, either of the terms, or both terms, regardless of where in the specification, claims, or drawings, unless the context dictates otherwise. For example, the phrase "A or B" will typically be understood to include the possibilities of "A" or "B" or "A and B."

[0081] With respect to the appended claims, those skilled in the art will understand that the operations described herein may generally be performed in any order. Also, while various operational flows are presented sequentially, it should be understood that various operations may occur in orders other than those illustrated, or may occur simultaneously. Examples of such alternative orderings may include overlapping, interleaved, interrupted, reordered, incremental, preliminary, additional, simultaneous, reverse, or other different orderings, unless the context dictates otherwise. Furthermore, terms such as "responsive to," "related to," or other past-tense adjectives are generally not intended to exclude such variants, unless the context dictates otherwise.

[0082] Those skilled in the art will appreciate that the specific example processes and / or devices and / or techniques described above are representative of more general processes and / or devices and / or techniques that are taught elsewhere in this specification, such as in the claims filed herewith and / or elsewhere in this application.

[0083] While various aspects and embodiments are disclosed herein, other aspects and embodiments will become apparent to those skilled in the art. The various aspects and embodiments disclosed herein are intended to be illustrative and not limiting, with the true scope and spirit being indicated by the following claims. The present invention also includes the following aspects. (Aspect 1) a tool body including a longitudinal central axis of rotation, the tool body being elongated and rotatable about the longitudinal central axis of rotation; a grooved cutting end including a radially circumferential surface and an end face, and a shank portion axially opposite the grooved cutting end; a plurality of major grooves located in the grooved cutting end, each major groove projecting radially inwardly of the tool body and including a major groove surface that extends continuously and spirally in an axial direction of the tool body; a plurality of flutes located in the fluted cutting end, each flute projecting radially inwardly of the tool body and including a flute surface having a plurality of discontinuous flute surface portions collectively extending spirally in the axial direction of the tool body, two consecutively adjacent large grooves are separated from one another by a plurality of teeth arranged in a band, each tooth of the plurality of teeth in the band being separated from the other by a first discontinuous groove surface portion of a first groove and a second discontinuous groove surface portion of a second groove, the first groove being consecutively adjacent to the second groove; the radially circumferential surface of each tooth of the plurality of teeth arranged in the band defines a face portion, the face portion having a periphery including first and second side edges that meet to form an apex, the apex being oriented such that the two side edges open in opposite directions relative to a cutting rotation direction of the rotary cutting tool; the first side edge of the face portion is formed by an intersection of the face portion with the groove surface of a first major groove, the first side edge defining a first cutting edge; the second side edge of the face portion is formed by an intersection of the face portion with the first discontinuous chamfer surface portion of the first chamfer, the second side edge defining a second cutting edge; a first region of the face portion extending from the first cutting edge toward an interior region of the face portion is non-planar and defines a clearance surface of the first cutting edge; a second region of the face portion extending from the second cutting edge toward the interior region of the face portion is non-planar and defines a clearance surface of the second cutting edge. (Aspect 2) 2. The rotary cutting tool of embodiment 1, wherein the flank surface of the first cutting edge and the flank surface of the second cutting edge are not coplanar and meet at a transition feature. (Aspect 3) 3. The rotary cutting tool of claim 1 or 2, wherein the first cutting edge, the second cutting edge, and the apex lie on a surface of an imaginary cylinder having a centroidal axis coincident with the longitudinal centroidal axis of rotation. (Aspect 4) 4. The rotary cutting tool of claim 3, wherein the flank surface of the first cutting edge and the flank surface of the second cutting edge radiate inward from the surface of the imaginary cylinder. (Aspect 5) 4. The rotary cutting tool of claim 3, wherein all other portions of the face portion radiate inward from the surface of the imaginary cylinder. (Aspect 6) 6. The rotary cutting tool of claim 4 or 5, wherein the surface radiating inward of the imaginary cylinder provides clearance for the first cutting edge and the second cutting edge in the cutting rotation direction of the rotary cutting tool. (Aspect 7) 7. The rotary cutting tool of claim 3, wherein an intersection of a plane perpendicular to the longitudinal axis of rotation and intersecting at least one tooth of the plurality of teeth arranged in a band with the surface portion forms a chord with an outer periphery of the imaginary cylinder. (Aspect 8) 8. The rotary cutting tool of claim 7, wherein the arc (θ) of the circumference of the imaginary cylinder between the endpoints of the chord is greater than or equal to 30 degrees and less than or equal to 45 degrees, alternatively greater than or equal to 30 degrees and less than or equal to 35 degrees, or 31±1 degrees. (Aspect 9) A rotary cutting tool according to any one of claims 1 to 8, wherein an arc length of the larger grooves exceeds an arc length of the smaller grooves in a cross section of the fluted cutting end taken perpendicular to the longitudinal axis of rotation. (Aspect 10) 10. The rotary cutting tool of embodiment 9, wherein the arc length of the smaller groove is greater than 0.5 x the arc length of the larger groove. (Aspect 11) 10. The rotary cutting tool of claim 9, wherein the arc-length of the larger groove is a non-integer multiple of the arc-length of the smaller groove, the non-integer multiple being greater than 1 and less than 5, alternatively greater than 1 and less than 4, or greater than 1 and less than 3. (Aspect 12) 12. The rotary cutting tool of any one of claims 1-11, wherein in a cross section taken through the flank surface of the first cutting edge and perpendicular to a transition feature, the flank surface of the first cutting edge comprises a curved surface having a first radius. (Aspect 13) 13. The rotary cutting tool of any one of aspects 1-12, wherein in a cross section taken through the flank surface of the second cutting edge and perpendicular to the transition feature, the flank surface of the second cutting edge comprises a curved surface having a second radius. (Aspect 14) In a cross section taken through the flank surface of the first cutting edge and perpendicular to the transition feature, the flank surface of the first cutting edge includes a curved surface having a first radius; In a cross section taken through the flank surface of the second cutting edge and perpendicular to the transition feature, the flank surface of the second cutting edge includes a curved surface having a second radius; 11. The rotary cutting tool of any one of embodiments 1 to 10, wherein the first radius and the second radius have the same length. (Aspect 15) In a cross section taken through the flank surface of the first cutting edge and perpendicular to the transition feature, the flank surface of the first cutting edge includes a curved surface having a first radius; In a cross section taken through the flank surface of the second cutting edge and perpendicular to the transition feature, the flank surface of the second cutting edge includes a curved surface having a second radius; 11. The rotary cutting tool of any one of embodiments 1-10, wherein the first radius length and the second radius length are different. (Aspect 16) In a cross section taken through the flank surface of the first cutting edge and perpendicular to the transition feature, the flank surface of the first cutting edge includes a first convex surface; 11. The rotary cutting tool of any one of aspects 1-10, wherein in a cross section taken through the flank surface of the second cutting edge and perpendicular to the transition feature, the flank surface of the second cutting edge comprises a second convex surface. (Aspect 17) 17. The rotary cutting tool of claim 16, wherein the first convex surface and the second convex surface have the same convexity. (Aspect 18) 17. The rotary cutting tool of embodiment 16, wherein the first convex surface and the second convex surface have different convexities. (Aspect 19) 19. The rotary cutting tool of any one of the preceding aspects, wherein an apex angle between the first and second side edges that meet to form the apex has a value that is greater than or equal to 40 degrees and less than or equal to 90 degrees, alternatively greater than or equal to 45 degrees and less than or equal to 70 degrees or greater than or equal to 55 degrees and less than or equal to 65 degrees, or equal to 60±1 degrees. (Aspect 20) 20. The rotary cutting tool of any one of the preceding aspects, wherein a helix angle (α) of each major flute has an absolute value of 45°≦|α|≦70°, or alternatively, 59°≦|α|≦61°. (Aspect 21) 21. The rotary cutting tool of any one of the preceding aspects, wherein a helix angle (β) of each flute has an absolute value of 45°≦|β|≦70°, or alternatively, 59°≦|β|≦61°. (Aspect 22) 22. The rotary cutting tool of embodiment 21, wherein the absolute value of the helix angle (α) of each major flute and the absolute value of the helix angle (β) of each minor flute are the same. (Aspect 23) 22. The rotary cutting tool of embodiment 21, wherein the absolute value of the helix angle (α) of each major flute and the absolute value of the helix angle (β) of each minor flute are different. (Aspect 24) 24. The rotary cutting tool of any one of the preceding embodiments, wherein each major flute has a positive peripheral rake angle (γ), where 9°≦γ≦11°, or alternatively γ=10°. (Aspect 25) 25. The rotary cutting tool of any one of the preceding embodiments, wherein each flute has a positive peripheral rake angle (ε), where 9°≦ε≦11°, or alternatively ε=10°. (Aspect 26) 26. The rotary cutting tool of any one of the preceding aspects, wherein helical centerlines of each of two consecutively adjacent large flutes are spaced apart at a constant distance along a longitudinal length of the fluted cutting end. (Aspect 27) 27. The rotary cutting tool of any one of claims 1 to 26, wherein in a plane perpendicular to the longitudinal axis of rotation and intersecting two consecutively adjacent teeth of the band of teeth, a portion of the first cutting edge is in front of a portion of the second cutting edge relative to the cutting rotation direction. (Aspect 28) 27. The rotary cutting tool of any one of claims 1 to 26, wherein a distance between transition features of adjacent teeth on a band, determined to be parallel to the longitudinal axis of rotation, defines a slope, and a longest distance between the first cutting edge and the second cutting edge of the face portion of one of the adjacent teeth defines a cutting width, the cutting width exceeding the slope. (Aspect 29)

[0031] Aspect 29. The rotary cutting tool of any one of aspects 1-28, wherein the periphery of the face portion has a quadrilateral shape. (Aspect 30) 30. The rotary cutting tool of embodiment 29, wherein the quadrilateral is a parallelogram or a rhombus. (Aspect 31) Aspect 31. The rotary cutting tool of any one of aspects 1-30, wherein the face portions of all teeth in one of the bands have the same geometric shape. (Aspect 32) Aspect 31. The rotary cutting tool of any one of aspects 1-30, wherein all of the teeth in one of the plurality of bands have the same geometric shape. (Aspect 33) 31. The rotary cutting tool of any one of the preceding embodiments, wherein each band has the same geometric shape. (Aspect 34) 34. The rotary cutting tool of any one of aspects 1 to 33, wherein the total number of major grooves in the plurality of major grooves is 2 to 6, alternatively 4. (Aspect 35) 35. The rotary cutting tool of any one of aspects 1 to 34, wherein a total number of flutes in the plurality of flutes is 4 to 12, alternatively 8. (Aspect 36) 36. The rotary cutting tool of any one of the preceding embodiments, wherein the major grooves have a radial depth greater than the radial depth of the minor grooves. (Aspect 37) 36. The rotary cutting tool of any one of the preceding aspects, wherein the larger flutes have a first core diameter and the smaller flutes have a second core diameter, the first core diameter being less than the second core diameter. (Aspect 38)

[0039] A rotary cutting tool according to any one of the preceding claims, wherein the major flutes are right-handed flutes and the minor flutes are left-handed flutes. (Aspect 39) 39. The rotary cutting tool of claim 38, wherein the first cutting edge is a right-hand cutting edge and the second cutting edge is a left-hand cutting edge. (Aspect 40)

[0039] Aspect 38. The rotary cutting tool of any one of aspects 1-37, wherein the major flutes are left-handed flutes and the minor flutes are right-handed flutes. (Aspect 41) 41. The rotary cutting tool of claim 40, wherein the first cutting edge is a left-hand cutting edge and the second cutting edge is a right-hand cutting edge. (Aspect 42)

[0072] Aspect 42. The rotary cutting tool of any one of aspects 1-41, wherein the end face of the fluted cutting end has the configuration of a center-cutting end mill. (Aspect 43)

[0072] Aspect 42. The rotary cutting tool of any one of aspects 1-41, wherein the end face of the fluted cutting end has a ball end mill configuration. (Aspect 44) 42. The rotary cutting tool of any one of the preceding claims, wherein the end face of the fluted cutting end has the configuration of a drill point end mill. (Aspect 45)

[0082] Aspect 45. The rotary cutting tool of any one of aspects 1-44, wherein the tool body has a cylindrical, conical, or undulating shape. (Aspect 46) 46. ​​The rotary cutting tool of any one of the previous embodiments, further comprising a coating on a surface of the fluted cutting end. (Aspect 47) 47. The rotary cutting tool of embodiment 46, wherein the coating is a chemical vapor deposition (CVD) coating. (Aspect 48) 48. The rotary cutting tool of embodiment 47, wherein the chemical vapor deposition coating is polycrystalline diamond (PCD). (Aspect 49) 47. The rotary cutting tool of embodiment 46, wherein the coating is a physical vapor deposition (PVD) coating. (Aspect 50) 50. The rotary cutting tool of embodiment 49, wherein the physical vapor deposition coating is diamond-like carbon (DLC), graphite, Ti(Al,N), Ti(C,N), Al(Ti,N), or Al(Cr,N). (Aspect 51) 1. A method for removing material from a workpiece, comprising: rotating the rotary cutting tool of any one of embodiments 1-50, wherein the rotary cutting tool is mounted on a spindle of a machine for machining; and removing material from the workpiece by contacting the first cutting edge and the second cutting edge with the workpiece. (Aspect 52) 52. The method of claim 51, wherein the workpiece is a fiber-reinforced composite material. (Aspect 53) 53. The method of claim 52, wherein the fiber-reinforced composite material is carbon fiber reinforced plastic (CRFP) or glass fiber reinforced plastic (GFRP). (Aspect 54) a tool body including a longitudinal central axis of rotation, the tool body being elongated and rotatable about the longitudinal central axis of rotation; a grooved cutting end including a radially circumferential surface and an end face, and a shank portion axially opposite the grooved cutting end; a plurality of right-hand grooves located in the grooved cutting end, each right-hand groove projecting radially inwardly of the tool body and including a groove surface that extends spirally in an axial direction of the tool body; a plurality of left-handed flutes located in the fluteed cutting end, each left-handed flute projecting radially inwardly of the tool body and including a flute surface extending in the axial direction of the tool body; the groove surface of each of the plurality of right-handed grooves is continuous along at least a majority of the helical length of the right-handed groove; the groove surface of each of the plurality of left-handed grooves is discontinuous along at least a majority of the helical length of the left-handed groove; Two adjacent right-handed grooves are separated from each other by a band of teeth, individual teeth of the band of teeth are separated from one another by a portion of one of the plurality of left-handed grooves; the radially circumferential surface of each tooth of the plurality of teeth arranged in the band defines a face portion, the face portion having a periphery including four side edges; a first set of two opposing side edges of the face portion are formed by intersections of the face portion with the groove surfaces of the two consecutively adjacent right-handed grooves, and a second set of two opposing edges of the face portion are formed by intersections of the face portion with the groove surfaces of the two consecutively adjacent left-handed grooves; first opposing edges of the first set intersect with first opposing edges of the second set to form leading apexes of the teeth, the first opposing edges of the first set defining right-hand cutting edges and the first opposing edges of the second set defining left-hand cutting edges, and the leading apexes of the teeth defining cutting points; a second opposing edge of the first set intersects a second opposing edge of the second set to form a trailing apex of the tooth; a region of the face portion extending from the right cutting edge to an imaginary line extending from the leading crest of the tooth to the trailing crest of the tooth defines a flank surface of the right cutting edge, and a region of the face portion extending from the left cutting edge to an imaginary line extending from the leading crest of the tooth to the trailing crest of the tooth defines a flank surface of the left cutting edge, The flank surface of the right cutting edge is non-planar, and the flank surface of the right cutting edge is non-planar, wherein the non-planar flank surface of the right cutting edge intersects the non-planar flank surface of the left cutting edge at the imaginary line extending from the leading crest of the tooth to the trailing crest of the tooth to form an angle therebetween. (Aspect 55) a tool body including a longitudinal central axis of rotation, the tool body being elongated and rotatable about the longitudinal central axis of rotation; a grooved cutting end including a radially circumferential surface and an end face, and a shank portion axially opposite the grooved cutting end; a plurality of right-hand grooves located in the grooved cutting end, each right-hand groove projecting radially inwardly of the tool body and including a groove surface that extends continuously and right-hand spirally in an axial direction of the tool body; a plurality of left-handed flutes located in the fluteed cutting end, each left-handed flute projecting radially inwardly of the tool body and including a groove surface having a plurality of discontinuous groove surface portions that collectively extend in a left-handed spiral in the axial direction of the tool body, two consecutively adjacent right-handed grooves separated from one another by a plurality of teeth arranged in a band, each tooth of the plurality of teeth in the band being separated from the other by a first discontinuous groove surface portion of a first left-handed groove and a second discontinuous groove surface portion of a second left-handed groove, the first left-handed groove being consecutively adjacent to the second left-handed groove; the radially circumferential surface of each tooth of the plurality of teeth arranged in the band defines a face portion, the face portion having a periphery including first and second side edges that meet to form an apex, the apex being oriented such that the two side edges open in opposite directions relative to a cutting rotation direction of the rotary cutting tool; the first side edge of the face portion is formed by an intersection of the face portion with the groove surface of a first right-handed groove, the first side edge defining a right cutting edge; the second side edge of the face portion is formed by an intersection of the face portion with the first discontinuous groove surface portion of the first left-handed groove, the second side edge defining a left-hand cutting edge; a first region of the face portion extending from the right cutting edge toward an interior region of the face portion is non-planar and defines a clearance surface for the right cutting edge; a second region of the face portion extending from the left cutting edge toward the interior region of the face portion is non-planar and defines a clearance surface for the left cutting edge; The rotary cutting tool, wherein the flank face of the right cutting edge and the flank face of the left cutting edge are not coplanar and meet at a transition feature. (Aspect 56) 1. A method of manufacturing a rotary cutting tool, comprising: forming a tool body including a longitudinal central axis of rotation, the tool body being elongated and rotatable about the longitudinal central axis of rotation; forming a plurality of major flutes and a plurality of minor flutes in the fluted cutting end of the tool body, each major flute including a major flute surface projecting radially inwardly from the tool body and extending continuously and spirally in an axial direction of the tool body, and each minor flute including a minor flute surface projecting radially inwardly from the tool body and having a plurality of discontinuous groove surface portions collectively extending spirally in the axial direction of the tool body, two consecutive adjacent major flutes being separated from one another by a plurality of teeth arranged in a band, each tooth of the band of teeth being separated from one another by a first discontinuous minor flute surface of a first minor flute and a second discontinuous minor flute surface of a second minor flute, the first minor flute being consecutively adjacent to the second minor flute; forming a surface profile on a radially circumferential surface of each tooth of the plurality of teeth arranged in the band, the surface profile defining a surface portion having a periphery including first and second side edges that meet to form an apex, the apex being oriented such that the two side edges open in opposite directions from a cutting rotation direction of the rotary cutting tool; the first side edge of the face portion is formed by an intersection of the face portion with the groove surface of a first major groove, the first side edge defining a first cutting edge; the second side edge of the face portion is formed by an intersection of the face portion with the first discontinuous groove surface of the first groove, the second side edge defining a second cutting edge; a first region of the face portion extending from the first cutting edge toward an interior region of the face portion is non-planar and defines a clearance surface of the first cutting edge; A second region of the face portion extending from the second cutting edge toward the interior region of the face portion is non-planar and defines a clearance surface of the second cutting edge. (Aspect 57) 57. The method of embodiment 56, wherein the flank surface of the first cutting edge and the flank surface of the second cutting edge are not coplanar and meet at a transition feature. (Aspect 58) 58. The method of claim 56 or 57, wherein forming the surface shape on the radially circumferential surface of each tooth includes grinding with a grinding wheel having a grinding form, the grinding form having a cross-sectional shape including a first concave surface and a second concave surface that intersect at a ridge. (Aspect 59) 59. The method of embodiment 58, wherein the first concave surface and the second concave surface have the same concave portion. (Aspect 60) 59. The method of embodiment 58, wherein the first concave surface and the second concave surface have different concave portions. (Aspect 61) A method according to any one of aspects 56 to 60, wherein the first cutting edge, the second cutting edge, and the apex are located on the surface of an imaginary cylinder having a centroid axis that coincides with the longitudinal rotational centroid axis, and the flanks of the first cutting edge and the second cutting edge radiate inward from the surface of the imaginary cylinder. (Aspect 62) Aspect 61. The method of any one of aspects 56 to 60, wherein the first cutting edge, the second cutting edge, and the apex are located on the surface of an imaginary cylinder having a centroid axis that coincides with the longitudinal centroid axis of rotation. (Aspect 63) 63. The method of claim 62, wherein all other portions of the surface portion radiate inwardly of the surface of the virtual cylinder. (Aspect 64) A method as described in aspect 61 or 63, wherein the surface radiating inward of the imaginary cylinder provides clearance for the first cutting edge and the second cutting edge in the cutting rotation direction of the rotary cutting tool. (Aspect 65) A method described in any one of aspects 61 to 64, wherein in a plane perpendicular to the longitudinal rotational center axis and intersecting at least one tooth of the plurality of teeth arranged in a band, the intersection of the plane and the surface portion forms a chord with the outer periphery of the imaginary cylinder. (Aspect 66) 66. The method of claim 65, wherein the arc (θ) of the circumference of the imaginary cylinder between the endpoints of the chord is greater than or equal to 30 degrees and less than or equal to 45 degrees, alternatively greater than or equal to 30 degrees and less than or equal to 35 degrees, or 31±1 degrees. (Aspect 67) 67. The method of any one of aspects 56 to 66, wherein the major groove is a right-handed groove and the minor groove is a left-handed groove. (Aspect 68) 68. The method of claim 67, wherein the first cutting edge is a right cutting edge and the second cutting edge is a left cutting edge. (Aspect 69) 67. The method of any one of aspects 56 to 66, wherein the major groove is a left-handed groove and the minor groove is a right-handed groove. (Aspect 70) 70. The method of claim 69, wherein the first cutting edge is a left cutting edge and the second cutting edge is a right cutting edge. (Aspect 71)

[0072] Aspect 71. The method of any one of aspects 56 to 70, further comprising coating a surface of the grooved cutting end with a chemical vapor deposition (CVD) coating or a physical vapor deposition (PVD) coating. (Aspect 72) 72. The method of embodiment 71, wherein the chemical vapor deposition coating is polycrystalline diamond (PCD). (Aspect 73) 72. The method of embodiment 71, wherein the physical vapor deposition coating is diamond-like carbon (DLC), graphite, Ti(Al,N), Ti(C,N), Al(Ti,N), or Al(Cr,N).

Claims

1. a tool body including a longitudinal central axis of rotation, the tool body being elongated and rotatable about the longitudinal central axis of rotation; a grooved cutting end including a radial circumferential surface and an end face, and a shank portion axially opposite the grooved cutting end; a plurality of major grooves located in the grooved cutting end, each major groove projecting radially inwardly of the tool body and including a major groove surface that extends continuously and spirally in an axial direction of the tool body; a plurality of flutes located in the flute cutting end, each flute projecting radially inwardly of the tool body and including a flute surface having a plurality of discontinuous flute surface portions collectively extending spirally in the axial direction of the tool body, two consecutively adjacent large grooves are separated from one another by a plurality of teeth arranged in a band, each tooth of the plurality of teeth in the band being separated from the other by a first discontinuous groove surface portion of a first groove and a second discontinuous groove surface portion of a second groove, the first groove being consecutively adjacent to the second groove; the radially circumferential surface of each tooth of the plurality of teeth arranged in the band defines a face portion, the face portion having a periphery including first and second side edges that meet to form an apex, the apex being oriented such that the two side edges open in a direction opposite to a cutting rotation direction of the rotary cutting tool; the first side edge of the face portion is formed by an intersection of the face portion with the groove surface of a first major groove, the first side edge defining a first cutting edge; the second side edge of the face portion is formed by an intersection of the face portion with the first discontinuous chamfer surface portion of the first chamfer, the second side edge defining a second cutting edge; a first region of the face portion extending from the first cutting edge toward an interior region of the face portion is non-planar and defines a clearance surface of the first cutting edge; a second region of the face portion extending from the second cutting edge toward the interior region of the face portion is non-planar and defines a clearance surface for the second cutting edge.

2. The rotary cutting tool of claim 1 , wherein the flank surface of the first cutting edge and the flank surface of the second cutting edge are not coplanar and meet at a transition feature.

3. 3. The rotary cutting tool according to claim 1, wherein the first cutting edge, the second cutting edge, and the apex lie on a surface of an imaginary cylinder having a center axis coincident with the longitudinal center axis of rotation.

4. The rotary cutting tool according to claim 3 , wherein all other portions of the surface portion face inward in a radial direction of the surface of the imaginary cylinder.

5. 5. The rotary cutting tool of claim 1, wherein in a cross section of the grooved cutting end perpendicular to the longitudinal axis of rotation, the arc length of the larger grooves is greater than the arc length of the smaller grooves.

6. In a cross section taken through the flank surface of the first cutting edge and perpendicular to the transition feature, the flank surface of the first cutting edge includes a curved surface having a first radius; In a cross section taken through the flank surface of the second cutting edge and perpendicular to the transition feature, the flank surface of the second cutting edge includes a curved surface having a second radius; The rotary cutting tool of claim 1 , wherein the first radius and the second radius have the same length.

7. 7. The rotary cutting tool according to claim 1, wherein the helix angle (α) of each major flute relative to the axial direction of the tool body has an absolute value of 45°≦|α|≦70°.

8. 8. The rotary cutting tool according to claim 1, wherein the helix angle (β) of each flute relative to the axial direction of the tool body has an absolute value of 45°≦|β|≦70°.

9. 9. The rotary cutting tool of claim 8, wherein the absolute value of the helix angle (α) of each major flute and the absolute value of the helix angle (β) of each minor flute are the same.

10. 10. The rotary cutting tool of claim 1, wherein each major flute has a positive peripheral rake angle (γ) in the range 9°≦γ≦11°.

11. 11. The rotary cutting tool of claim 1, wherein each flute has a positive peripheral rake angle (ε) in the range 9°≦ε≦11°.

12. 12. The rotary cutting tool of claim 1, wherein a distance between transition features of adjacent teeth on a band, determined to be parallel to the longitudinal central axis of rotation, defines a pitch, and a longest distance between the first cutting edge and the second cutting edge of the face portion of one of the adjacent teeth defines a cutting width, the cutting width exceeding the pitch.

13. The rotary cutting tool of claim 1 , wherein the periphery of the face portion has a quadrilateral, parallelogram, or diamond shape.

14. The rotary cutting tool of claim 12 , wherein all of the teeth in one of the bands have the same geometric shape.

15. 15. The rotary cutting tool of claim 1, wherein the radial depth of the major grooves is greater than the radial depth of the minor grooves.

16. 16. The rotary cutting tool of claim 1, wherein the major flutes are right-handed flutes and the minor flutes are left-handed flutes.

17. 1. A method for removing material from a fiber-reinforced composite material, comprising: Rotating a rotary cutting tool according to any one of claims 1 to 16 mounted on a spindle of a machine for machining; removing material from the fiber-reinforced composite material by contacting the first cutting blade and the second cutting blade with the fiber-reinforced composite material.

18. 18. The method of claim 17, wherein the fiber reinforced composite material is carbon fiber reinforced plastic (CRFP) or glass fiber reinforced plastic (GFRP).

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