Rotary cutting tool having continuous primary chip flutes and discontinuous secondary chip flutes intersecting to form a quadrilateral face portion

Abstract

A rotary cutting tool (100) has a plurality of main chip grooves (130), the plurality of main chip grooves (130) being arranged spirally relative to a plurality of discontinuous auxiliary chip grooves (135), and intersecting to form a plurality of teeth. Each tooth includes a first cutting edge formed with the main chip groove and a second cutting edge formed with the auxiliary chip groove, the first cutting edge and the second cutting edge meeting at a vertex and forming a portion of the periphery of a quadrilateral facial portion. The facial portion has a non-planar surface extending from the respective first and second cutting edges, the non-planar surface defining a flank surface of each cutting edge. The first and second cutting edges are arranged on an imaginary cylinder having a central axis coaxial with the axis of rotation of the tool, and the respective flank surfaces are radially inward relative to the surface of the imaginary cylinder, so that the first and second cutting edges both have a gap in the direction of rotation of the tool.

Description

Technical Field

[0001] The present disclosure relates to a cutting tool, and more particularly, to a rotary cutting tool (such as an end mill) for machining a workpiece, wherein the chip groove system and tooth geometry of the cutting tool are designed for improved machining, in particular, improved machining of fiber composite materials. The rotary cutting tool has a plurality of continuous primary chip grooves and a plurality of discontinuous secondary chip grooves, wherein the plurality of continuous primary chip grooves are spirally arranged relative to the plurality of discontinuous secondary chip grooves, the two types of chip grooves intersecting to form a tooth having a first cutting edge formed with a primary chip groove and a second cutting edge formed with a secondary chip groove, the first cutting edge and the second cutting edge converging at a vertex and forming a portion of the periphery of a quadrilateral facial portion of the tooth. The surface of the facial portion extending from the respective first and second cutting edges defines a flank face of the respective cutting edge, the flank face being radially inward from the surface of an imaginary cylinder containing the cutting edges, which ensures that there is no surface contact between the facial portion and the workpiece during machining using the tool. The cutting edges and flank faces improve cutting dynamics, in particular when machining fiber composite materials. The present disclosure also relates to a method of manufacturing such a rotary cutting tool. Background Art

[0002] In the discussion that follows, reference is made to certain structures and / or methods. However, the following references should not be construed as an admission that these structures and / or methods constitute prior art. Applicants expressly reserve the right to demonstrate that such structures and / or methods do not conform to prior art as an objection to the present invention.

[0003] Composite materials can provide performance advantages in various applications, mainly due to properties such as weight reduction and increased flexibility. However, composite materials may also be more difficult to process than other materials (such as metal or wood). Common composite materials are usually composed of multiple layers of fibers and resins that are bonded together by high temperature and / or pressure. Processing composite materials requires passing through these different layers composed of various material types, such as by peeling, tearing or chopping. Each of these layers reacts differently when cutting, and if not processed properly, the heat generated by the cutting tool may cause delamination or other failure modes, and may cause excessive wear of the tool.

[0004] Common problems when machining composites include, for example, delamination of composite layers, uncut fibers, fiber tearing, uneven tool wear and poor surface finish. These problems are caused by conditions created by the composite material itself and can be difficult to correct. At the same time, the simple fact of cutting a combination of materials introduces many factors that make it difficult to strike the right balance between the right tool for the job and the proper operating parameters. In addition, when machining with conventional rotary cutting tools, non-point or linear contact between the cutting edge and the fiber composite can lead to fiber pull-out, delamination and other faults resulting in uneven cutting edges, which need to be avoided.

[0005] Several types of conventional cutting tools are known for machining composite materials. For example, straight flute composite tools are designed to prevent delamination of multiple layers of material by applying all cutting forces radially, thereby eliminating the axial forces of a typical helical cutting edge. Using a higher positive rake angle can improve the cutting effect on shearing fibers and combine with an eccentric relief angle to improve edge life.

[0006] Another example is a compression tool that consists of an up-cutting spiral and a down-cutting spiral. The top portion of the cutting length has right-handed cutting teeth with a left-handed spiral, while the lower portion of the cutting length has right-handed cutting teeth with a right-handed spiral. This geometry creates opposing cutting forces that can stabilize the material removal process when cutting multi-layer composites and can prevent delamination, fiber pullout, and burrs along the surface. Compression of the top and bottom of the workpiece can keep the layers together.

[0007] Other examples include special geometries such as a cutting tool with a notched chip breaker in which all the flutes are oriented in the same direction and which shears the fibers and shortens the chips to improve material evacuation, and a diamond cutting composite tool having a combination of left-handed and right-handed teeth with a downcut geometry on the outer diameter that is traditionally thought to result in a poor surface finish. Also, a composite finishing cutting tool (with increased contact points due to slow spiral and high flute count) can be used for finishing. Examples of conventional cutting tools for composites are shown and described at https: / / www.harveyperformance.com / in-the-loupe / tooling-machining-com posites / , the contents of which are incorporated herein by reference.

[0008] Even with the types of conventional tools described above that can be used to machine composites, there remains a need for further improvements in cutting tool design to further optimize performance in machining of composites and to minimize or prevent fiber pullout, delamination, and other failure modes that can result in cutting edge irregularities in the finished workpiece. Summary of the invention

[0009] The disclosed rotary cutting tool has a chip relief system and a tooth geometry in which the vertices of the two cutting edges (in the direction of machining rotation of the tool) are the leading points (i.e., cutting points) of contact with the workpiece during machining, and each cutting edge has a true / effective relief face that ensures that 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 pullout, delamination, and other malfunctions resulting in uneven cutting edges that may occur through non-point or linear contact between the cutting edge and the fiber composite material observed in conventional rotary cutting tools.

[0010] In general, the disclosed rotary cutting tool has a plurality of continuous main chip grooves and a plurality of discontinuous auxiliary chip grooves, the plurality of continuous main chip grooves being arranged spirally relative to the plurality of discontinuous auxiliary chip grooves. The teeth are formed by the intersection of the continuous main chip grooves and the discontinuous auxiliary chip grooves, and each tooth includes a first cutting edge formed with the main chip groove and a second cutting edge formed with the auxiliary chip groove. The first cutting edge and the second cutting edge meet at the vertex and form a portion of the periphery of the quadrilateral facial portion of the tooth, and the surface of the facial portion extending from the respective first cutting edge and the second cutting edge defines a flank face of the respective cutting edge, the flank face being radially inward from the surface of the imaginary cylinder containing the cutting edge, which ensures that there is no surface contact between the facial portion and the workpiece during machining using the tool. The vertex is the point that first contacts the workpiece during machining, followed by the cutting edge, and the workpiece material is initially put into compression during the penetration phase of machining (i.e., the period when the vertex and the trailing cutting edge penetrate into the workpiece). As the tool rotates further, the apex passes the point of maximum penetration depth into the workpiece, and the rotational motion of the tool causes the apex (and the trailing cutting edge) to withdraw from the workpiece. During this withdrawal phase, the fibers in the fiber composite are in tension, and the cutting mode is in shear. Shearing of the fibers of the fiber composite has been shown to reduce pullout and other faults that can cause uneven cutting edges, and therefore, the disclosed rotary cutting tool produces an improved finish on the cut surface of the workpiece.

[0011] An embodiment of the disclosed rotary cutting tool includes: a tool body, the tool body including a longitudinal center rotation axis, the tool body is elongated and can rotate along the longitudinal center rotation axis; a cutting end portion with a chip groove and a shank portion axially opposite to the cutting end portion with the chip groove, the cutting end portion with the chip groove including a radial peripheral surface and an end face; a plurality of main chip grooves, the plurality of main chip grooves are located in the cutting end portion with the chip groove, each main chip groove includes a main chip groove surface, the main chip groove surface radially protrudes inwardly into the tool body and extends continuously and spirally in the axial direction of the tool body; and a plurality of auxiliary chip grooves, the plurality of auxiliary chip grooves are located in the cutting end portion with the chip groove, each auxiliary chip groove includes an auxiliary chip groove surface, the auxiliary chip groove surface radially protrudes inwardly into the tool body and has a plurality of discontinuous auxiliary chip groove surface portions, the plurality of discontinuous auxiliary chip groove surface portions extend spirally together in the axial direction of the tool body. Two consecutively adjacent primary chip grooves are separated from each other by a plurality of teeth arranged in a toothed band, and each of the plurality of teeth in the toothed band is separated from each other by a first discontinuous secondary chip groove surface portion of a first secondary chip groove and a second discontinuous secondary chip groove surface portion of a second secondary chip groove, the first secondary chip groove being consecutively adjacent to the second secondary chip groove. The radial peripheral surface of each of the plurality of teeth arranged in the toothed band defines a facial portion, and the facial portion has a periphery including a first side edge and a second side edge, the first side edge and the second side edge converge to form a vertex, the vertex being oriented so that the two side edges are open opposite to the cutting rotation direction of the rotating cutting tool. The first side edge of the facial portion is formed by the intersection of the facial portion and the chip groove surface of the first primary chip groove, the first side edge defines a first cutting edge, and the second side edge of the facial portion is formed by the intersection of the facial portion and the first discontinuous secondary chip groove surface portion of the first secondary chip groove, the second side edge defines a second cutting edge. In addition, a first region of the facial portion extending from the first cutting edge toward an interior region of the facial portion is non-planar and defines a back surface of the first cutting edge, and a second region of the facial portion extending from the second cutting edge toward an interior region of the facial portion is non-planar and defines a back surface of the second cutting edge.

[0012] An embodiment of the disclosed rotary cutting tool includes: a tool body, the tool body including a longitudinal center rotation axis, the tool body is elongated and can rotate along the longitudinal center rotation axis; a cutting end portion with a chip groove and a shank portion axially opposite to the cutting end portion with the chip groove, the cutting end portion with the chip groove including a radial peripheral surface and an end face; a plurality of right-handed chip grooves, the plurality of right-handed chip grooves are located in the cutting end portion with the chip groove, each right-handed chip groove includes a chip groove surface, the chip groove surface radially protrudes inwardly into the tool body and extends spirally in the axial direction of the tool body; and a plurality of left-handed chip grooves, the plurality of left-handed chip grooves are located in the cutting end portion with the chip groove, each left-handed chip groove includes a chip groove surface, the chip groove surface radially protrudes inwardly into the tool body and extends in the axial direction of the tool body. The chip groove surface of each of the plurality of right-handed chip grooves is continuous along at least a majority of the spiral length of the right-handed chip groove, and the chip groove surface of each of the plurality of left-handed chip grooves is discontinuous along at least a majority of the spiral length of the left-handed chip groove. Two consecutively adjacent right-handed chip grooves are separated from each other by a plurality of teeth arranged in a toothed belt, and each of the plurality of teeth in the toothed belt is separated from each other by a portion of one of the plurality of left-handed chip grooves. The radial peripheral surface of each of the plurality of teeth arranged in the toothed belt defines a facial portion, the facial portion having a periphery including four side edges, wherein a first set of two opposite side edges of the facial portion are formed by the intersection of the facial portion and the chip groove surfaces of the two consecutively adjacent right-handed chip grooves, and a second set of two opposite edges of the facial portion are formed by the intersection of the facial portion and the chip groove surfaces of the two consecutively adjacent left-handed chip grooves. The first relative edges of the first group intersect with the first relative edges of the second group to form the leading vertex of the tooth, the first relative edges of the first group define a right-handed cutting edge, the first relative edges of the second group define a left-handed cutting edge, and the leading vertex of the tooth defines a cutting point. The second relative edges of the first group intersect with the second relative edges of the second group to form the trailing vertex of the tooth. The area of ​​the facial portion extending from the right-handed cutting edge to an imaginary line extending from the leading vertex of the tooth to the trailing vertex of the tooth defines a flank surface of the right-handed cutting edge, and the area of ​​the facial portion extending from the left-handed cutting edge to the imaginary line extending from the leading vertex of the tooth to the trailing vertex of the tooth defines a flank surface of the left-handed cutting edge, wherein the flank surface of the right-handed cutting edge is non-planar, and the flank surface of the right-handed cutting edge is non-planar. The non-planar flank surface of the right-handed cutting edge intersects with the non-planar flank surface of the left-handed cutting edge at the imaginary line extending from the leading vertex of the tooth to the trailing vertex of the tooth to form an angle therebetween.

[0013] Another embodiment of the disclosed rotary cutting tool includes: a tool body, the tool body including a longitudinal center rotation axis, the tool body is elongated and can rotate along the longitudinal center rotation axis; a cutting end portion with a chip groove and a shank portion axially opposite to the cutting end portion with the chip groove, the cutting end portion with the chip groove including a radial peripheral surface and an end face; a plurality of right-handed chip grooves, the plurality of right-handed chip grooves are located in the cutting end portion with the chip groove, each right-handed chip groove includes a chip groove surface, the chip groove surface radially protrudes inwardly into the tool body and extends continuously and right-handedly in the axial direction of the tool body; and a plurality of left-handed chip grooves, the plurality of left-handed chip grooves are located in the cutting end portion with the chip groove, each left-handed chip groove includes a chip groove surface, the chip groove surface radially protrudes inwardly into the tool body and has a plurality of discontinuous chip groove surface portions, the plurality of discontinuous chip groove surface portions extend together in a left-handedly in the axial direction of the tool body. Two sequentially adjacent right-handed chip flutes are separated from each other by a plurality of teeth arranged in a toothed belt, and each of the plurality of teeth in the toothed belt is separated from each other by a first discontinuous chip flute surface portion of a first left-handed chip flute and a second discontinuous chip flute surface portion of a second left-handed chip flute, the first left-handed chip flute being sequentially adjacent to the second left-handed chip flute. The radial peripheral surface of each of the plurality of teeth arranged in the toothed belt defines a facial portion, the facial portion having a periphery including a first side edge and a second side edge, the first side edge and the second side edge converging to form a vertex, the vertex being oriented so that the two side edges are open opposite to the cutting rotation direction of the rotary cutting tool. The first side edge of the facial portion is formed by the intersection of the facial portion and the chip flute surface of the first right-handed chip flute, the first side edge defining a right-handed cutting edge, and the second side edge of the facial portion is formed by the intersection of the facial portion and the first discontinuous chip flute surface portion of the first left-handed chip flute, the second side edge defining a left-handed cutting edge. A first region of the facial portion extending from the right-handed cutting edge toward the interior region of the facial portion is non-planar and defines a relief surface of the right-handed cutting edge, and a second region of the facial portion extending from the left-handed cutting edge toward the interior region of the facial portion is non-planar and defines a relief surface of the left-handed cutting edge, and wherein the relief surface of the right-handed cutting edge and the relief surface of the left-handed cutting edge are not coplanar and merge at a transition feature.

[0014] Embodiments of the disclosed rotary cutting tool can be used to remove material from a workpiece, for example, by rotating the rotary cutting tool when mounted on a spindle of an apparatus for machining and by contacting a first cutting edge and a second cutting edge with the workpiece. An example workpiece is a fiber reinforced composite material, such as a carbon fiber reinforced plastic (CRFP) or a glass fiber reinforced plastic (GFRP).

[0015] An embodiment of the disclosed rotary cutting tool can be manufactured by, for example, the following method, which includes: forming a tool body including a longitudinal central rotation axis, the tool body being elongated and capable of rotating along the longitudinal central rotation axis; forming a plurality of main chip grooves and a plurality of auxiliary chip grooves in a cutting end portion of the tool body with chip grooves, each main chip groove including a main chip groove surface, the main chip groove surface protruding radially inward into the tool body and extending continuously and spirally in the axial direction of the tool body, and each auxiliary chip groove including an auxiliary chip groove surface, the auxiliary chip groove surface protruding radially inward into the tool body and having a plurality of discontinuous chip groove surface portions, the plurality of discontinuous chip groove surface portions being collectively arranged in the axial direction of the tool body. The invention relates to a toothed belt having a plurality of teeth disposed in a toothed belt, wherein two consecutively adjacent primary chip grooves are separated from each other by a plurality of teeth disposed in a toothed belt, and each of the plurality of teeth in the toothed belt is separated from each other by a first discontinuous secondary chip groove surface of a first secondary chip groove and a second discontinuous secondary chip groove surface of a second secondary chip groove, the first secondary chip groove being consecutively adjacent to the second secondary chip groove; and a surface profile is formed on a radial peripheral surface of each of the plurality of teeth disposed in the toothed belt, wherein the surface profile defines a facial portion having a periphery including a first side edge and a second side edge, the first side edge and the second side edge converging to form a vertex, the vertex being oriented so that the two side edges are open opposite to the cutting rotation direction of the rotary cutting tool. The first side edge of the facial portion is formed by the intersection of the facial portion and the chip groove surface of the first primary chip groove, the first side edge defines a first cutting edge, and the second side edge of the facial portion is formed by the intersection of the facial portion and the first discontinuous secondary chip groove surface of the first secondary chip groove, the second side edge defines a second cutting edge. A first region of the facial portion extending from the first cutting edge toward an interior region of the facial portion is non-planar and defines a relief surface of the first cutting edge, and a second region of the facial portion extending from the second cutting edge toward an interior region of the facial portion is non-planar and defines a relief surface of the second cutting edge.

[0016] Additional aspects, features and advantages will be set forth in the following description and will become apparent in part from the description or may be understood by the practice of the invention. The purposes and other advantages of the disclosed rotary cutting tool will be realized and obtained by the written description and claims thereof and the structures specifically pointed out in the drawings. However, other systems, methods, features and advantages will be or will become apparent to those skilled in the art after examining the following drawings and specific embodiments, and all such additional systems, methods, features and advantages are intended to be included in this description, within the scope of the present disclosure and protected by the attached claims. Nothing in this section shall be construed as a limitation on the claims. It should be understood that the foregoing general description of the disclosed cutting tool and the following specific embodiments are examples and illustrative, and are intended to provide further explanation of the disclosed cutting tool claimed. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0018] Figure 1A and Figure 1B are isometric views at two different angles of a rotary cutting tool having continuous primary chip flutes in a right-hand configuration and discontinuous secondary chip flutes in a left-hand configuration in accordance with one embodiment of the disclosed cutting tool.

[0019] Figure 2A and Figure 2B are isometric views at two different angles of a rotary cutting tool according to another embodiment of the disclosed cutting tool having continuous primary chip flutes in a left-hand configuration and discontinuous secondary chip flutes in a right-hand configuration.

[0020] Figure 3 is a side plan view of a rotary cutting tool having continuous right-handed primary chip flutes and discontinuous left-handed auxiliary chip flutes.

[0021] Figure 4 yes Figure 3 An enlarged plan side view of the cutting end portion P1 with chip relief grooves is shown.

[0022] Figure 5 is Figure 4 An enlarged plan view of a portion of the toothed belt shown in section P2.

[0023] Figure 6 is Figure 4 A cross-sectional view of the cutting end portion with chip relief grooves taken along section VI-VI is shown.

[0024] FIG. 7 is an enlarged view of a portion P3 in FIG. 6 .

[0025] Figure 8 is Figure 4 A cross-sectional view of the cutting end portion with chip relief grooves taken along section VIII-VIII is shown.

[0026] Fig. 9 is a cross-sectional view of a fluted cutting end portion in a plane perpendicular to the longitudinal central axis of rotation showing the features of the primary flutes.

[0027] Fig.10 is a cross-sectional view of a fluted cutting end portion in a plane perpendicular to the longitudinal central axis of rotation showing the features of the auxiliary flutes.

[0028] Fig.11 is an enlarged isometric view of a portion of a fluted cutting end portion of a rotary cutting tool and illustrating the relationship of the cutting edges on two consecutive teeth in a toothed band of teeth.

[0029] Fig.12 is an enlarged isometric view of a portion of a fluted cutting end portion of a rotary cutting tool and illustrating the relationship of transition features on two consecutive teeth in a toothed band.

[0030] Fig.13A is a view of an end face of an exemplary embodiment of a rotary cutting tool having a center cutting end mill configuration as seen along a longitudinal center rotational axis.

[0031] Fig. 13B is a view of an end face of an exemplary embodiment of a rotary cutting tool having a ball nose end mill configuration as seen along a longitudinal center rotational axis.

[0032] Fig. 13C is a view of an end face of an exemplary embodiment of a rotary cutting tool having a drill end mill configuration as seen along a longitudinal center rotational axis.

[0033] Fig.14 Steps in a method of making an embodiment of the disclosed cutting tool are shown.

[0034] Fig.15 and Fig.16 Aspects of a grinding process that may be used to form a surface profile and define a face portion on a radial peripheral surface of each of a plurality of teeth arranged in a toothed belt are schematically illustrated.

[0035] Fig.17A A workpiece made of carbon reinforced composite material is shown, which has been machined by a rotary cutting tool according to an embodiment, and Fig. 17BAn enlarged view of a portion of the machined edge is shown.

[0036] Note that for ease of viewing, not all instances of features shown in the Figures are labeled with a reference numeral.

[0037] Throughout the drawings and detailed description, unless otherwise indicated, the same reference numerals shall be understood to refer to the same elements, features and structures, unless the context indicates otherwise. For clarity, illustration and convenience, the relative sizes and descriptions of these elements may be exaggerated. In addition, in some instances, reference numerals are not applied to each instance of each feature in a particular drawing to reduce the complexity of the reference numerals for marking and also to improve the overall understanding of the information conveyed in the drawings. In such instances, the identification of unmarked features can be easily understood from the specification and other reference numerals. DETAILED DESCRIPTION

[0038] In the following detailed description, reference is made to the accompanying drawings that form a part thereof. In the drawings, the use of similar or identical reference numerals in different drawings generally indicates similar or identical items unless the context indicates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be used, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. The progression of processing steps and / or operations described is an example; however, except for steps and / or operations that must occur in a particular order, the order of steps and / or operations is not limited to those set forth herein and may be changed as known in the art.

[0039] Those skilled in the art will recognize that the components (e.g., operations), devices, objects, and discussions accompanying them described herein are used as examples to make the concepts clear, and various structural modifications are contemplated. Therefore, as used herein, the specific examples set forth and the accompanying discussions are intended to represent their more general categories. In general, the use of any specific example is intended to represent its category, and the non-inclusion of specific components (e.g., operations), devices, and objects should not be considered limiting.

[0040] This application uses formal outline headings for clarity of presentation. However, it should be understood that the outline headings are for presentation purposes, and different types of subject matter may be discussed throughout the application (e.g., devices / structures may be described under device / structure headings and / or processes / operations may be discussed under structure / process headings; and / or, the description of a single subject may span two or more subject headings). Therefore, the use of formal outline headings is not intended to be limiting in any way.

[0041] The aspects, features and advantages of the disclosed rotary cutting tool may be embodied in a rotary cutting tool in which a continuous primary chip groove is right-handed and a discontinuous secondary chip groove is left-handed, or in a rotary cutting tool in which a continuous primary chip groove is left-handed and a discontinuous secondary chip groove is right-handed. Regardless of the handedness, the primary chip groove provides chip evacuation and is used for material removal, and the intersecting orientation of the primary chip groove and the secondary chip groove produces the cutting edge of the rotary cutting tool. Although the following description will focus on an embodiment in which the continuous primary chip groove is right-handed and the discontinuous secondary chip groove is left-handed, it should be understood that the corresponding aspects, features, functions and advantages disclosed with respect to a rotary cutting tool having a continuous right-handed primary chip groove and a discontinuous left-handed secondary chip groove may be embodied in a rotary cutting tool having a continuous left-handed primary chip groove and a discontinuous right-handed secondary chip groove.

[0042] Figure 1A and Figure 1B 1 are isometric views at two different angles of a rotary cutting tool according to an embodiment of the disclosed cutting tool, the cutting tool having a continuous primary chip groove in a right-handed configuration and a discontinuous secondary chip groove in a left-handed configuration. The rotary cutting tool 100 includes a tool body 105, which is elongated and rotatable (R1) along a longitudinal center rotation axis 110. Optionally, the tool body 110 can have one of a cylindrical, conical or contoured shape. The rotary cutting tool 100 has a cutting end portion 112 with a chip groove and a shank portion 114. The shank portion 114 is axially opposite to the cutting end portion 112 with a chip groove (relative to the longitudinal center rotation axis 110). The cutting end portion 112 with a chip groove includes a radial peripheral surface 120 and an end face 125. In some embodiments, the peripheral surface 120 extends axially rearwardly from the end face 125 in the direction of the longitudinal central rotational axis 110 to a position along the tool body 100 at which the fluted cutting end portion 112 transitions directly into the shank portion 114. In other embodiments, one or more intermediate portions are disposed between the fluted cutting end portion 112 and the shank portion 114. At the end of the tool 100 axially opposite the end face 125, the shank portion 114 may optionally have a means for attaching the rotary cutting tool 100 (e.g., via a chuck or clamping device) to equipment used for machining, such as a machine tool or a computer numerical control (CNC) machine tool.

[0043] A plurality of primary chip grooves 130 and a plurality of secondary chip grooves 135 are located in the fluted cutting end portion 112. Each primary chip groove 130 includes a primary chip groove surface 140 that protrudes radially inward (relative to the longitudinal center rotation axis 110) into the tool body 105 and extends continuously and spirally in the axial direction (relative to the longitudinal center rotation axis 110) of the tool body 105. In some embodiments, the primary chip groove surface 140 is continuous along at least a portion (e.g., a majority) of the spiral length of the primary chip groove 130. In other embodiments, the primary chip groove surface 140 is continuous along the entire spiral length of the primary chip groove 130. Each secondary chip groove 135 includes a secondary chip groove surface 145 that protrudes radially inward (relative to the longitudinal center rotation axis 110) into the tool body 105. A plurality of discontinuous auxiliary chip groove surface portions 150 together form an auxiliary chip groove surface 145, and in any one of the auxiliary chip grooves 135, together extend spirally in the axial direction of the tool body 105. For ease of viewing and as an example, the auxiliary chip groove 135 is identified by a dotted line connecting the discontinuous auxiliary chip groove surface portions 150 of one auxiliary chip groove surface 135a. In some embodiments, the auxiliary chip groove surface 145 is discontinuous along at least a portion (e.g., a majority) of the spiral length of the auxiliary chip groove 135. In other embodiments, the auxiliary chip groove surface 145 is continuous along the entire spiral length of the auxiliary chip groove 135.

[0044] The number of primary chip flutes 130 and the number of secondary chip flutes 135 in the rotary cutting tool 100 can vary. In an exemplary embodiment, the total number of primary chip flutes 130 in the plurality of primary chip flutes is 2 to 6, alternatively 4, and the total number of secondary chip flutes 135 in the plurality of secondary chip flutes is 4 to 12, alternatively 8. In some aspects, the total number of primary chip flutes 130 is less than the total number of secondary chip flutes 135. In other aspects, the total number of primary chip flutes 130 is the same as the total number of secondary chip flutes 135.

[0045] Figure 1A and Figure 1B The exemplary embodiment shown in FIG. 1 is a right-handed tool (meaning that the tool 100 rotates counterclockwise to perform cutting (as indicated by the longitudinal center axis of rotation 110 when viewed from the end face 125). Figure 1A and Figure 1B ), but other embodiments may be left-handed tools (as further discussed herein).

[0046] Figure 2A and Figure 2B2 isometric views of a rotary cutting tool according to another embodiment of the disclosed cutting tool having a continuous primary chip flute in a left-handed configuration and a discontinuous secondary chip flute in a right-handed configuration. In addition to the different handedness of the primary and secondary chip flutes and the resulting different rotational directions for machining, Figure 2A and Figure 2B The features, geometry, functions and advantages of the rotary cutting tool 200 in Figure 1A and Figure 1B 2. The rotary cutting tool 200 has similar features, geometry and functions to the rotary cutting tool 100 in the embodiment of the present invention. Thus, the rotary cutting tool 200 includes a tool body 205 that is elongated and rotatable (R2) along a longitudinal center rotation axis 210. The rotary cutting tool 200 has a cutting end portion 212 with a chip groove and a shank portion 214. The shank portion 214 is axially opposite (relative to the longitudinal center rotation axis 210) to the cutting end portion 212 with a chip groove. The cutting end portion 212 with a chip groove includes a radial peripheral surface 220 and an end face 225. In some embodiments, the peripheral surface 220 extends axially backward from the end face 225 in the direction of the longitudinal center rotation axis 210 to such a position along the tool body 200 that the cutting end portion 212 with a chip groove directly transforms into the shank portion 214. In other embodiments, one or more intermediate portions are placed between the cutting end portion 212 with a chip groove and the shank portion 214. A plurality of primary chip grooves 230 and a plurality of secondary chip grooves 235 are located in the chip grooved cutting end portion 212. Each primary chip groove 230 includes a primary chip groove surface 240 that projects radially inwardly (relative to the longitudinal center rotation axis 210) into the tool body 205 and extends continuously and spirally in the axial direction (relative to the longitudinal center rotation axis 210) of the tool body 205. Each secondary chip groove 235 includes a secondary chip groove surface 245 that projects radially inwardly (relative to the longitudinal center rotation axis 210) into the tool body 205. The secondary chip groove surface 245 includes a plurality of discontinuous chip groove surface portions 250 that together form the secondary chip groove surface 245 and that, in any one of the secondary chip grooves 235, together extend spirally in the axial direction of the tool body 205.

[0047] Figure 3 is a side plan view of a rotary cutting tool 100 having continuous right-handed primary flutes 130 and discontinuous left-handed secondary flutes 135, and Figure 4 yes Figure 3 An enlarged side plan view of the cutting end portion P1 with chip relief grooves is shown. Figure 3 and Figure 4In the embodiment of the present invention, two consecutively adjacent main chip grooves (such as the main chip grooves 130a and 130b) are separated from each other by a plurality of teeth 305 arranged in the toothed belt 300. For ease of observation and as an example, the toothed belt 300a composed of the teeth 305 is identified by a dotted line connecting the teeth 305 of one toothed belt 300a. Each of the plurality of teeth 305 in the toothed belt 300 is separated from each other by a first discontinuous auxiliary chip groove surface portion 150a of a first auxiliary chip groove 135 and a second discontinuous auxiliary chip groove surface portion 150b of a second auxiliary chip groove 135 (the first auxiliary chip groove 135 is consecutively adjacent to the second auxiliary chip groove 135).

[0048] Figure 5 is Figure 4 FIG. 5 is an enlarged plan view of a portion of a toothed belt formed by the teeth shown in section P2 of FIG. In FIG. 5 , the radial peripheral surface of the tooth 305 is shown. FIG. 5 also shows an area of ​​the cutting tool 100 adjacent to the tooth 305, including the main chip groove surface 140 (from two consecutive right-handed main chip grooves 130) and the first discontinuous auxiliary chip groove surface portion 150a of the first auxiliary chip groove 135 and the second discontinuous auxiliary chip groove surface portion 150b of the second auxiliary chip groove 135 (the first auxiliary chip groove 135 is adjacent to the second auxiliary chip groove 135 in sequence). The radial peripheral surface of the tooth defines a facial portion 310 having a periphery 320. The periphery 320 includes a first side edge 325 formed by the intersection of the facial portion 310 and the chip groove surface 140 of the first main chip groove 130. The first side edge 325 defines a first cutting edge. The perimeter 320 also includes a second side edge 330 formed by the intersection of the face portion 310 and the discontinuous auxiliary flute surface portion 150a of the auxiliary flute 135. The second side edge 330 defines a second cutting edge. The first side edge 325 and the second side edge 330 converge to form a vertex 335, which is oriented so that the two side edges 325, 330 are open opposite to the cutting rotation direction (R1) of the rotary cutting tool 100. Given this arrangement, the vertex 335 is the leading edge during cutting (in the cutting rotation direction R1 of the rotary cutting tool).

[0049] The handedness of the cutting edge depends on the handedness of the rotary cutting tool. For example, in a right-handed rotary cutting tool, the first side edge defines a right-handed cutting edge, and the second side edge defines a left-handed cutting edge. For another example, in a left-handed rotary cutting tool, the first side edge defines a left-handed cutting edge, and the second side edge defines a right-handed cutting edge.

[0050] The first region 340 of the face portion 310 extends from the first cutting edge (defined by the first side edge 325) toward the interior region of the face portion 310. The second region 350 of the face portion 310 extends from the second cutting edge (defined by the second side edge 330) toward the interior region of the face portion. Both the first region 340 and the second region 350 are non-planar and define the relief surfaces of their respective cutting edges, i.e., the first region 340 defines the relief surface of the first cutting edge and the second region 350 defines the relief surface of the second cutting edge.

[0051] Figure 6 is Figure 4 FIG. 7 is a cross-sectional view of the cutting end portion with chip relief grooves taken along section VI-VI, and FIG. 7 is an enlarged view of portion P3 in FIG. 6. The cross section in FIG. 6 is located in a plane parallel to and containing the longitudinal center rotation axis 110. It should also be noted that FIG. 7 is equivalent to Figure 4 A cross section of the tooth in the portion P2 of FIG. 5 taken along section VI-VI and a cross section of the tooth in FIG. 5 taken along section VII-VII. FIG. 7 further illustrates the shapes of the first region 340 and the second region 350 used as the flank surfaces of the first cutting edge (defined by the first side edge 325) and the second cutting edge (defined by the second side edge 330). As can be seen in FIG. 7, both the first region 340 and the second region 350 are non-planar. In some aspects, the first region 340 (defining the flank surface of the first cutting edge) includes a curved surface having a first radius (r1). In other aspects, the second region 350 (defining the flank surface of the second cutting edge) includes a curved surface having a second radius (r2). In one embodiment, the first region 340 (defining the flank surface of the first cutting edge) includes a curved surface having a first radius (r1), and the second region 350 (defining the flank surface of the second cutting edge) includes a curved surface having a second radius (r2), and the length of the first radius (r1) and the length of the second radius (r2) are the same. In a second embodiment, the first region 340 (defining the back surface of the first cutting edge) includes a curved surface having a first radius (r1), and the second region 350 (defining the back surface of the second cutting edge) includes a curved surface having a second radius (r2), and the length of the first radius (r1) and the length of the second radius (r2) are different.

[0052] In other alternative embodiments, the shapes of the first region 340 and the second region 350 can be convex or have different or more than one convex shape. For example, in some embodiments, the first region 340 (defining the back face of the first cutting edge) includes a surface having more than one convex area. In other embodiments, the second region 350 (defining the back face of the second cutting edge) includes a surface having more than one convex area. The convex shapes associated with the first region 340 and the second region 350 can be the same or different between the two regions. In addition, these convex shapes can be simple, such as curves associated with a circle or ellipse or parabola, or can be complex, such as curves associated with a cubic (or higher order) polynomial function.

[0053] In yet another alternative embodiment, the shape of the first region 340 and the second region 350 may be other than curved or may be a series of short, connected planar surfaces that approximate curved surfaces.

[0054] The flank surface of the first cutting edge and the flank surface of the second cutting edge meet at a transition feature 360. The transition feature 360 ​​may be a feature formed by the meeting of two non-coplanar flank surfaces 340, 350, such as as a line that may be visible as a line or may be an imaginary line caused by the meeting of two non-coplanar flank surfaces. As such, the feature may be formed by the angle between the two non-coplanar flank surfaces 340, 350. Alternatively, the transition feature 360 ​​may be a radiused surface connecting the two angled non-coplanar flank surfaces 340, 350. In another alternative, the transition feature 360 ​​may be a planar surface, such as a facet connecting the two angled non-coplanar flank surfaces 340, 350, and the transition from the planar surface to each of the angled two non-coplanar flank surfaces 340, 350 may itself be angled or radiused.

[0055] FIG. 5 shows the transition feature 360 ​​as a straight line, but the back face feature 360 ​​can have alternative forms, such as a curve or a sawtooth pattern. In addition, as shown in FIG. 5, the back face feature bisects the vertex angle (Φ). However, in other embodiments, the transition feature 360 ​​is non-bisect and can be oriented (over its length extending from the vertex 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 an exemplary embodiment, the vertex angle (Φ) has a value equal to or greater than 40 degrees and equal to or less than 90 degrees, alternatively, equal to or greater than 45 degrees and equal to or less than 70 degrees, or equal to or greater than 55 degrees and equal to or less than 65 degrees, or equal to 60±1 degrees.

[0056] In an 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 vertex 335 are located on the surface of an imaginary cylinder 400 having a central axis that coincides with the longitudinal central axis of rotation 110. The first cutting edge (defined by the first side edge 325) and the second cutting edge (defined by the second side edge 330) located on the surface of the imaginary cylinder 400 can be seen from Figures 6 and 7. As can be seen in Figures 6 and 7, the first cutting edge (defined by the first side edge 325) coincides with and is located on the surface of the imaginary cylinder 400. Similarly, the second cutting edge (defined by the second side edge 330) coincides with and is located on the surface of the imaginary cylinder 400. In one aspect, the first region 340 (defining the relief surface of the first cutting edge) and the second region 350 (defining the relief surface of the second cutting edge) are radially inward (relative to the longitudinal central axis of rotation 110) relative to the surface of the imaginary cylinder 400. In this arrangement, the tail vertex 370 can coincide with and be located on the surface of the imaginary cylinder 400 (see the tail vertex 370 in FIG. 8 located on the imaginary cylinder 400). In other aspects, all other portions of the face portion 310 (i.e., all portions other than the first cutting edge (defined by the first side edge 325), the second cutting edge (defined by the second side edge 330), and the vertex 335) are radially inward (relative to the longitudinal center rotation axis 110) relative to the surface of the imaginary cylinder 400. In this regard, "all other portions" include the tail vertex 370 and other portions of the periphery 320 of the face portion 310, such as (for the quadrilateral face portion 310 shown in FIG. 5) the tail first side edge 380 and the tail second side edge 385. In both aspects, these surfaces radially inward relative to the surface of the imaginary cylinder 400 provide clearance for the first cutting edge and the second cutting edge in the cutting rotation direction (R) of the rotary cutting tool 100.

[0057] 5, the perimeter 320 of the facial portion 310 has a quadrilateral shape. In some embodiments, the quadrilateral is a parallelogram, while in other embodiments, the quadrilateral is a rhombus.

[0058] Returning to Figure 8, Figure 8 is Figure 4A cross-sectional view of the cutting end portion with chip relief grooves taken along section VIII-VIII is shown, which shows the spatial relationship between the periphery 320 of the face portion 310 and the surface of the imaginary cylinder 400. The view of FIG8 shows a cross section in a plane perpendicular to the longitudinal central rotation axis 110 and intersecting at least one tooth 305 of the plurality of teeth arranged in the toothed belt 300. In this view, the intersection between the plane and the face portion 310 forms a chord 410 with the circumference of the imaginary cylinder 400. The chord 410 has end points 415 and 420. The arc (θ) of the circumference of the imaginary cylinder 400 between the end points 415, 420 of the chord 410 is equal to or greater than 30 degrees and equal to or less than 45 degrees, alternatively, equal to or greater than 30 degrees and equal to or less than 35 degrees, or 31±1 degrees.

[0059] Referring also to FIG8 , both the primary chip groove 130 and the secondary chip groove 135 can be observed. In the cross section of FIG8 , it is easy to observe that the arc length 440 of the primary chip groove 130 is greater than the arc length 445 of the secondary chip groove 135. In one aspect, a plurality of secondary chip grooves can be seen through the opening of the primary chip groove, thereby visually confirming that the arc length 440 of the primary chip groove 130 is greater than the arc length 445 of the secondary chip groove 135. In one aspect, the arc length 445 of the secondary chip groove 135 is greater than (0.5×the arc length 440 of the primary chip groove 130). In another aspect, the arc length 440 of the primary chip groove 130 is a non-integer multiple of the arc length 445 of the secondary chip groove 135, and 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.

[0060] With further reference to the cross-section shown in FIG8 , the radial rake angle associated with each of the primary chip groove 130 and the auxiliary chip groove 135 can be observed. The radial rake angle is the angle formed by the rake face of the chip groove and the radius measured in a plane perpendicular to the longitudinal center rotation axis 110. As shown in FIG8 , each primary chip groove 130 has a positive radial rake angle (γ), and each auxiliary chip groove 135 has a positive radial rake angle (ε). In an exemplary embodiment, the positive radial rake angle (γ) is 9°<=γ<=11°, alternatively, γ=10°, and the positive radial rake angle (ε) is 9°<=ε<=11°, alternatively, ε=10°.

[0061] In general, in exemplary embodiments of the rotary cutting tool, each toothed belt 300 of teeth 305 has the same geometry in at least some aspects, and in some embodiments, each toothed belt 300 of teeth 305 has the same geometry in all aspects. In some aspects, at least each tooth 305 in one of the plurality of toothed belts 300 has the same geometry, but the geometry of the teeth 305 in one toothed belt 300 may be different from the geometry of the teeth 305 in a second toothed belt 300. In other aspects, at least each tooth 305 in one of the plurality of toothed belts 300 has the same geometry, but the geometry of the teeth 305 in one toothed belt 300 may be different from the geometry of the teeth 305 in the second toothed belt 300. In still other aspects, the face portion 310 of each tooth 305 in one of the plurality of toothed belts 300 has the same geometry.

[0062] Both the primary flute 130 and the secondary flute 135 have helical centerlines, which are imaginary lines located at the most radially inward surfaces of the respective flutes. Figure 4 Annotated with examples of a helical centerline 500 of a primary chip groove 130 and a helical centerline 510 of an auxiliary chip groove 135, and FIG. 6 is annotated with the location of the most radially inward surface of the primary chip groove 130 where the helical centerline 500 is located. The helical centerline represents the helical geometry of the corresponding chip groove, and the angle formed between the helical centerline and an imaginary plane containing the longitudinal center rotation axis 110 represents the helix angle of the chip groove. For example, the angle formed between the helical centerline 500 of the primary chip groove 130 and the imaginary plane containing the longitudinal center rotation axis 110 represents the helix angle (α) of the primary chip groove 130, and the angle formed between the helical centerline 510 of the auxiliary chip groove 135 and the imaginary plane containing the longitudinal center rotation axis 110 represents the helix angle (β) of the auxiliary chip groove 135. In an exemplary embodiment, the helix angle (α) of each main chip groove 130 has an absolute value of 45°<=|α|<=70°, alternatively, 59°<=|α|<=61°, and the helix angle (β) of each auxiliary chip groove 135 has an absolute value of 45°<=|β|<=70°, alternatively, 59°<=|β|<=61°. In one aspect, the absolute value of the helix angle (α) of each main chip groove 130 and the absolute value of the helix angle (β) of each auxiliary chip groove 135 are the same. In another aspect, the absolute value of the helix angle (α) of each main chip groove 130 and the absolute value of the helix angle (β) of each auxiliary chip groove 135 are different.

[0063] In an additional embodiment, the spiral centerline 500 of each of two consecutive primary chip flutes 130 is at a constant separation distance along the longitudinal length of the fluted cutting end portion 112. FIG. 6 is annotated to show an example of a separation distance D1 between the spiral centerlines 500a, 500b of two consecutive primary chip flutes 130a, 130b. In an exemplary embodiment, the separation distance D1 is a function of the tool diameter, the spiral lead, and the number of primary chip flutes.

[0064] Fig. 9 is a cross-sectional view of the fluted cutting end portion 112 in a plane perpendicular to the longitudinal center rotational axis 110 , illustrating features of the primary flutes 130 . Fig. 9 The distribution of the primary chip flutes 130 around the circumference of the tool and the cross-sectional shape of the primary chip flute surface 140 are schematically shown. The tool has a first core diameter defined by an imaginary circle 520 centered on the longitudinal central rotation axis 110 and having a circumference connecting the most radially inward surfaces of the primary chip flutes 130 (i.e., the location on the primary chip flute surface 140 where the spiral centerline 500 is 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 primary chip flutes 130.

[0065] Fig.10 is a cross-sectional view of the fluted cutting end portion 112 in a plane perpendicular to the longitudinal center rotational axis 110 , illustrating the features of the auxiliary flutes 135 . Fig.10 The distribution of the auxiliary chip grooves 135 around the circumference of the tool and the cross-sectional shape of the auxiliary chip groove surface 145 are schematically shown. The tool has a second core diameter defined by an imaginary circle 530 centered on the longitudinal central rotation axis 110 and having a circumference connecting the most radially inward surfaces of the auxiliary chip grooves 135 (i.e., the position on the auxiliary chip groove surface 140 where the spiral centerline 510 is 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 auxiliary chip groove 135.

[0066] In an exemplary embodiment, the value of r4 is 60% of the value of r3, and the value of r5 is 80% of the value of r3.

[0067] In one aspect of the rotary cutting tool 100, the first core diameter of the primary chip flute 130 is smaller than the second core diameter of the auxiliary chip flute 135. In other words, the length of the radius (r4) of the first core of the primary chip flute 130 is smaller than the length of the radius (r5) of the second core of the auxiliary chip flute 135. In another aspect of the rotary cutting tool 100, the radial depth of the primary chip flute 130 is greater than the radial depth of the auxiliary chip flute 135.

[0068] Still Fig. 9 and Fig.10 It can be seen in FIG. 1 that the positive radial rake angle (γ) of the primary chip groove 130 and the positive radial rake angle (ε) of the auxiliary chip groove 135 .

[0069] Fig.11 is an enlarged isometric perspective view of a portion of the fluted cutting end portion 112 of the rotary cutting tool 100 and illustrates the relationship of the cutting edges on two consecutive teeth 305 in the toothed band of teeth 300 . Fig.11 is viewed in a direction perpendicular to a plane containing the longitudinal central rotation axis 110. Fig.11 The toothed belt of the illustrated teeth 300 is formed with a first tooth 305a and a second tooth 305b separated by an auxiliary chip relief groove 135. In the depicted embodiment, the first tooth 305a is a leading tooth (in the cutting rotation direction (R1) and relative to the second tooth 305b). The first tooth 305a has a first cutting edge (defined by the first side edge 325a) and a second cutting edge (defined by the second side edge 330a) that meet at an apex 335a, and the second tooth 305b has a first cutting edge (defined by the first side edge 325b) and a second cutting edge (defined by the second side edge 330b) that meet at an apex 335b. Fig.11 Also shown is the overlap between the first tooth 305a (as the leading tooth) and the second tooth 305b (as the trailing tooth) (in the cutting rotational direction (R)). At least a portion of the first cutting edge (defined by the first side edge 325a) of the first tooth 305a axially overlaps (in the axial direction relative to the longitudinal center rotational axis 110) with at least a portion of the second cutting edge (defined by the first side edge 330b) of the second tooth 305b. Fig.11, the overlap is illustrated as an overlap amount (Δ). In a particular embodiment, a tail portion 580 of a first cutting edge (defined by a first side edge 325a) of a first tooth 305a axially overlaps a tail portion 585 of a second cutting edge (defined by a first side edge 330b) of a second tooth 305b. In an exemplary embodiment, the overlap amount (Δ) is 6% to 10% of the pitch (P). When viewed in a plane perpendicular to the longitudinal center rotation axis and intersecting two sequentially adjacent teeth of a plurality of teeth arranged in the toothed belt, i.e., in a plane located at the position of the overlap amount (Δ), a portion of the first cutting edge (defined by a first side edge 325a) of a first tooth 305a is in front of a portion of the second cutting edge (defined by a first side edge 330b) of a second tooth 305b relative to the cutting rotation direction (R). When the tool 100 rotates in the cutting rotation direction (R1) during machining of a workpiece, the overlap (Δ) ensures that there is no gap in the effective cutting edge of the tool 100 formed by the teeth 305 in the toothed belt formed by the teeth 300 and ensures that a smooth finish is provided on the workpiece.

[0070] Fig.12 is an enlarged isometric perspective view of a portion of the fluted cutting end portion 112 of the rotary cutting tool 100 and illustrates the relationship of transition features 360 on two consecutive teeth 305 in the toothed band of teeth 300 . Fig.12 and Fig.11 The views shown are the same. Fig.12 In the toothed belt formed by the teeth 300 shown, the distance (D2) between the transition features 360 of adjacent teeth 305 on one toothed belt 300 (determined parallel to the longitudinal center rotational axis 110) defines the pitch (P) of the teeth. Moreover, the maximum distance (D3) (determined parallel to the longitudinal center rotational axis 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 the face portion 310 of one of the teeth 305 defines the cutting width (W). In an exemplary embodiment, the cutting width (W) is greater than the pitch (P). When the pitch (P) and width (W) of the plurality of teeth 305 in the toothed belt formed by the teeth 300 are constant, the width (W) being greater than the pitch (P) ensures that when the tool 100 rotates in the cutting rotational direction (R1) during machining of a workpiece, there is no gap in the effective cutting edge of the tool 100 formed by the teeth 305 in the toothed belt formed by the teeth 300.

[0071] The end face 125 of the rotary cutting tool 100 may have any of the various forms known in the art for end mills. Fig.13A As shown, Fig.13A1 is a view of the end face as seen along the longitudinal center axis of rotation 110, the end face 125 may have a center cutting end mill configuration. In the center cutting end mill configuration, the end face 125 is planar in a side plan view (see also Figure 3 to Figure 4 6) and includes an end cutting edge 600. The portion of the end cutting edge 600 that coincides with the planar end face 125 is straight in the radial direction (see Fig.13A ).

[0072] In another example and as Fig. 13B As shown, Fig. 13B 1 is a view of the end face as seen along the longitudinal center axis of rotation 110 , the end face 125 may have a ball nose end mill configuration with a curved cutting edge 610 .

[0073] In another example and as Fig. 13C As shown, Fig. 13C 1 is a view of the end face as seen along the longitudinal center rotation axis 110, the end face 125 may have a drill end mill construction with a first axially angled cutting edge 620a and a second axially angled cutting edge 620b (typically straight cutting edges) forming an angle of the drill tip 625, and two offset angled cutting edges 630a and 630b (typically straight cutting edges).

[0074] However, the features, improvements, methods, processes and other technical details disclosed herein can also be applied to other categories and types of rotary cutting tools, such as other types of end mills, face mills, side mills and drilling tools with point geometries.

[0075] Optionally, the rotary cutting tool may include a coating located on the surface of the fluted cutting end portion 112. In one aspect, the coating is located on all surfaces of the fluted cutting end portion 112. In other aspects, the coating is located on portions of the surfaces of the fluted cutting end portion, the cutting edge, the facial portion, or a combination of the above. In yet another aspect, the coating is located on a portion of the fluted cutting end portion 112 including the primary fluted surface 140, the secondary fluted 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 flank face of the first cutting edge), the second region 350 (defining the flank face of the second cutting edge), or a combination of these surfaces. Furthermore, in some aspects, the coating is located on the surface along the entire axial length of the fluted cutting end portion 112, while in other aspects, the coating is located on the surface along a portion of the axial length of the fluted cutting end portion 112, such as the first 50%, alternatively, the first 25%, of the axial length of the fluted cutting end portion 112 rearward from the end face 125. In each of the above, the end face 125 may or may not be coated.

[0076] 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. An 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 has a thickness of 100 nanometers to 3 microns, alternatively, a thickness of 1 micron to 2 microns.

[0077] Optionally, embodiments of the rotary cutting tool 100 may have internal passages for delivering coolant (liquid or gaseous) to the cutting region. When present, such internal passages may extend internally in the longitudinal direction and be helically inclined as desired to extend from the shank portion 114 to an outlet opening in the fluted cutting end portion 112, typically in the flute surfaces 140, 145 and / or in the surface of the end face 125.

[0078] Furthermore, the features disclosed and described herein and shown in the accompanying drawings are generally implemented in solid body rotary cutting tools in which the flutes and teeth (and associated features, including the geometry of the cutting edges and face portions) are integrally formed with the tool body. However, the flutes and teeth (and associated features, including the geometry of the cutting edges and face portions) may also be implemented in tools using removable cutting inserts.

[0079] Fig.14 Steps in a method of making an embodiment of the disclosed cutting tool are shown. Fig.14 The illustrated method 700 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, a blank of the tool body is formed by consolidating a hard material such as tungsten cemented carbide (WC) or tungsten cobalt carbide (WC-Co) as a solid body of hard material, with or without carbide particles such as titanium carbide (TiC) or tantalum carbide (TaC). Other materials such as tool steel, high speed steel, and ceramics may be used for the tool body.

[0080] After forming a blank of the tool body 105, a plurality of primary chip flutes 130 and a plurality of secondary chip flutes 135 are formed 720 in the fluted cutting end portion 112 of the blank. In some embodiments of the method 700, the solid body of the blank may be formed as a rod, in which case the plurality of primary chip flutes 130 and a plurality of secondary chip flutes 135 are formed in the fluted cutting end portion 112 of the tool body 105 by suitable material removal means, such as by grinding and / or polishing. It is also contemplated that additive manufacturing methods may be applied to manufacture a rough form of the tool, which is then finally machined to a final form, such as by grinding and / or polishing.

[0081] Grinding can be performed by any suitable technique, such as using CBN, alumina and diamond grinding wheels, and is typically aided by computer controlled positioning and translation equipment. Machining removes material from the spiral flutes (both primary and secondary) to have selected values ​​of helix angle (α) and helix angle (β), and produces teeth having selected values ​​of apex angle (Φ) and rake angles (γ) and (ε), all within the ranges disclosed herein (and taking into account manufacturing tolerances).

[0082] For the removable cutting blade rotary cutting tool, the blank of the tool body is made by any suitable technology, including those technologies discussed above for solid body rotary cutting tools, for example. The blank has a tool body in the form of an overall elongated shape and includes a spirally extended chip groove. The placement pocket for the removable indexable cutting blade is formed in the toothed belt formed by the teeth. The size, spacing and orientation of the placement pocket are correspondingly designed to accommodate the intended removable indexable cutting blade in the desired orientation, for various relevant features and surfaces of the tooth, including the first side edge 325 and the second side edge 330 (the first side edge 325 and the second side edge 330 converge to form a vertex 335) and the features of the facial portion 310, all of which are formed on the removable indexable cutting blade.

[0083] It is also contemplated that the rotary cutting tool may implement a combination of features formed integrally with the tool body and features formed on a removable indexable cutting insert that is then mounted in a seating pocket on the rotary cutting tool.

[0084] In other embodiments of the method 700, a solid body of the tool body 105 may be directly formed (at least in rough form) using powder metallurgy techniques, in which case a plurality of primary chip grooves 130 and a plurality of secondary chip grooves 135 (having one or more of the various features disclosed herein) are formed in the chip grooved cutting end portion 112 of the tool body 105 by a molding process used in a powder metallurgy process. In some cases, the chip grooves formed using powder metallurgy techniques are subsequently finished by grinding or other techniques to obtain final dimensions and surface finish.

[0085] After the flute profile of the tool body has been formed, a surface profile is formed 730 on the radial peripheral surface of each tooth 305 of the plurality of teeth arranged in the toothed belt 300. The surface profile defines a face portion 310 having one or more of the various features disclosed herein.

[0086] In one embodiment, the surface profile is formed by grinding. Fig.15 and Fig.16 Schematically illustrates aspects of a grinding process that may be used to form a surface profile on a radial peripheral surface of each of a plurality of teeth arranged in a toothed belt. Fig.15As shown schematically, a grinding wheel 800 having a grinding profile 805 is in rotational contact with a surface to be ground on a radial peripheral surface of a tooth. The grinding profile, the tool body, or both can be rotated to affect the rotation of the rotating contact. The grinding profile 805 has a cross-sectional profile that is a negative image of the desired surface profiles of the first region 340 of the face portion 310 and the second region 350 of the face portion 310 (which define the respective relief surfaces of the first cutting edge and the second cutting edge). In the illustrated example, the grinding profile 805 has a cross-sectional profile including a first concave surface 810 and a second concave surface 820 that meet at a ridge 830. During the grinding operation, the ridge 830 is generally aligned with the vertex 335 of the quadrilateral face portion 310. Since the ridge 830 forms the transition feature 360, it also performs grinding so that the transition feature 360 ​​is formed at a desired position and orientation relative to the features of the face portion 310 (such as the side edges 325, 330, 380, 385 and the tail vertex 370).

[0087] Fig.16 FIG. 3 is a side cross-sectional view of the facial portion 310 of the tooth 305, showing the leading vertex 335, transition feature 360, trailing vertex 370, and cutting edge of the tooth. Fig.16 As shown, the facial portion 310 is at a radial relief angle (ψ) of 15 ± 1 degrees.

[0088] Optionally, the method 700 further includes coating the surface of the fluted cutting tip portion 120 with a chemical vapor deposition (CVD) coating or a physical vapor deposition (PVD) coating, as disclosed herein.

[0089] Embodiments of the disclosed rotary cutting tool can be used in machining operations to remove material from a workpiece. For example, embodiments of the disclosed rotary cutting tool can be mounted on a spindle of a machine tool for machining, such as a machine tool or a computer numerical control (CNC) machine tool. Typically, the shank portion 114 will be clamped or otherwise fixed to the spindle for axially rotating the rotary cutting tool 100 around the longitudinal center axis of rotation 110. Then, the mounted rotary cutting tool 100 is rotated and material of the workpiece 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, during machining, the vertex 335 first contacts the workpiece. Alternatively, a rotary cutting tool having the above-described radial cutting edge (and its associated features, including one or more of the tooth pattern and the rake face) can be mounted in a fixed position in the machine tool for machining, and the workpiece can be positioned, moved and / or rotated and contacted with the radial cutting edge to remove material from the workpiece. The workpiece may be a metal material (which may be ferrous or non-ferrous), a metal alloy material, a natural material or a synthetic material, or a composite material of two or more different materials. In a particular embodiment, the workpiece is a fiber-reinforced composite material, such as a carbon fiber reinforced plastic (CRFP) or a glass fiber reinforced plastic (GFRP). The geometry of the helix angle (α, β), radial rake angle (γ, ε), radian (θ), and vertex angle (Φ) will typically vary at least in part based on the characteristics of the material to be processed and will result in different tooth geometries. These geometries can be adjusted based on, for example, the number of fiber layers, the orientation of the fibers, and the stacking combination of layers and materials (such as a stack of aluminum or aramid outer layers).

[0090] As an example, embodiments of the disclosed rotary cutting tools may be used in machining operations to remove material from a workpiece of carbon reinforced composite material. Fig.17A A workpiece 700 of carbon fiber reinforced plastic (CRFP) is shown that has been machined by a rotary cutting tool according to the disclosed embodiments. The workpiece 700 has been machined by a center cutting end mill having right-handed primary flutes and left-handed secondary flutes by milling an edge 705 . Fig. 17B Shows the corresponding Fig.17A 705 of a portion of the processed edge 705 of portion P3 in FIG. As can be seen in the enlarged view, there is no evidence of delamination or ply breakage, nor is there fiber pullout or unsheared fibers.

[0091] Example: The following information in Table 1 describes an embodiment of a cutting tool manufactured consistent with the embodiments disclosed herein:

[0092] Table 1

[0093] Example Example A Tool diameter 10mm Tool length 75mm Main chip groove type / auxiliary chip groove type Right / Left Helix angle (α) 60 degrees Helix angle (β) 60 degrees Vertex angle(Φ) 60 degrees Radial rake angle (γ) 10 degrees Radial rake angle (ε) 10 degrees Overlap (Δ) 0.086mm Pitch(P) 1.08mm

[0094] As previously mentioned, the disclosed rotary cutting tool may be embodied as a rotary cutting tool in which the continuous main chip grooves are right-handed and the discontinuous auxiliary chip grooves are left-handed, or as a rotary cutting tool in which the continuous main chip grooves are left-handed and the discontinuous auxiliary chip grooves are right-handed. Figure 1A and Figure 1B ), the primary chip flute is a right-handed chip flute and the secondary chip flute is a left-handed chip flute, and the first cutting edge is a right-handed cutting edge and the second cutting edge is a left-handed cutting edge. In the embodiment where the continuous primary chip flute is left-handed and the discontinuous secondary chip flute is right-handed (see for example Figure 2A and Figure 2B ), the primary chip flute is a left-handed chip flute and the secondary chip flute is a right-handed chip flute, and 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 the embodiment of the rotary cutting tool with continuous right-handed primary chip flutes and discontinuous left-handed secondary chip flutes may be present alone or in combination in the embodiment of the rotary cutting tool with continuous left-handed primary chip flutes and discontinuous right-handed secondary chip flutes.

[0095] While the present invention has been described in conjunction with the embodiments thereof, those skilled in the art will appreciate that additions, deletions, modifications and substitutions not specifically described may be made without departing from the spirit and scope of the invention as defined in the appended claims.

[0096] With respect to the use of substantially any plural and / or singular terms herein, those skilled in the art can translate from the plural to the singular and / or from the singular to the plural as is appropriate to the context and / or application. For clarity, various singular / plural arrangements are not expressly set forth herein.

[0097] The subject matter described herein sometimes illustrates different components that are contained in or connected to different other components.It should be understood that the architecture described in this way is only exemplary, and in fact many other architectures that realize the same function can be realized.Conceptually, any arrangement of the components that realize the same function is effectively "associated", so as to realize the desired function.Therefore, any two components that are combined to realize a specific function herein can be regarded as "associated" to each other, so as to realize the desired function, and have nothing to do with the architecture or intermediate components.Similarly, any two components that are so associated can also be regarded as "operably connected" or "operably connected" to realize the desired function, and any two components that can be so associated can also be regarded as "operably connectable" to each other to realize the desired function.The specific example that can be operably connected includes, but is not limited to, physically matchable and / or physically interactive components, and / or wirelessly interactive and / or wirelessly interactive components, and / or logically interactive and / or logically interactive components.

[0098] In some cases, one or more components may be referred to herein as being "configured to," "configured of," "configurable to," "operable / operable for," "suitable / adaptable to," "capable of," "conformable / conformable to," etc. Those skilled in the art will recognize that these terms (e.g., "configured to") may generally encompass active state components and / or inactive state components and / or standby state components unless the context requires otherwise.

[0099] Although particular aspects of the subject matter of the invention 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 will cover within their scope all such changes and modifications within the true spirit and scope of the subject matter described herein. It will be understood by those skilled in the art that, in general, the terms used herein, particularly in the appended claims (e.g., the body of the appended claims), are generally intended to be "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 "including" should be interpreted as "including, but not limited to", etc.). It will be further understood by those skilled in the art that if a specific number of introduced claim recitations is intended, such intent will be explicitly stated in the claim, and in the absence of such a statement, there is no such intent. For example, to aid understanding, the following appended claims may include the use of 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 implying that the introduction of a claim recitation by the indefinite article "a" or "an" limits any particular claim containing such introduced claim recitation to claims containing only one such recitation, even if the same claim includes 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 generally be interpreted as "at least one" or "one or more"); the same is true of the use of definite articles to introduce claim recitations. Furthermore, even if a specific number of introduced claim recitations is explicitly recited, those skilled in the art will recognize that such recitation should generally be interpreted to mean at least the recited number (e.g., the simple recitation of "two recitations," without other modifiers, generally means at least two recitations, or two or more recitations). Furthermore, in those cases where a convention similar to “at least one of A, B, and C, etc.” is used, generally, such construction is intended in the sense that one skilled in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include, 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 those cases where a convention similar to “at least one of A, B, or C, etc.” is used, generally, such construction is intended in the sense that one skilled in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include, 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.).Those skilled in the art will further understand that, generally, whether in the specification, claims or drawings, unless the context indicates otherwise, separate words and / or phrases presenting two or more alternative terms should be understood to include the possibility of one, either or both of the terms. For example, the phrase "A or B" will generally be understood to include the possibility of "A" or "B" or "A and B".

[0100] With respect to the appended claims, those skilled in the art will appreciate that the operations described therein may generally be performed in any order. Moreover, although the various operational flows are presented in order, it should be understood that the various operations may be performed in other orders than those shown, or may be performed simultaneously. Unless the context indicates otherwise, examples of such alternative orderings may include overlapping, interleaved, interrupted, reordered, incremental, preparatory, supplementary, simultaneous, reverse, or other variant orderings. Furthermore, unless the context indicates otherwise, terms such as "responsive to," "related to," or other past tense adjectives are generally not intended to exclude such variants.

[0101] Those skilled in the art will appreciate that the foregoing specific exemplary processes and / or apparatus and / or techniques are representative of more general processes and / or apparatus and / or techniques taught elsewhere herein, such as in the claims filed herein and / or elsewhere in this application.

[0102] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

Claims

1. A rotary cutting tool comprising: a tool body including a longitudinal central rotational axis, the tool body being elongated and rotatable along the longitudinal central rotational axis; a fluted cutting end portion and a shank portion axially opposed to the fluted cutting end portion, the fluted cutting end portion comprising a radial peripheral surface and an end surface; a plurality of primary chip flutes located in the fluted cutting end portion, each primary chip flute comprising a primary chip flute surface that projects radially inwardly into the tool body and extends continuously and helically in an axial direction of the tool body; as well as a plurality of auxiliary chip grooves, the plurality of auxiliary chip grooves being located in the fluted cutting end portion, each auxiliary chip groove comprising an auxiliary chip groove surface, the auxiliary chip groove surface protruding radially inwardly into the tool body and having a plurality of discontinuous auxiliary chip groove surface portions, the plurality of discontinuous auxiliary chip groove surface portions collectively extending helically in the axial direction of the tool body; wherein two consecutively adjacent main chip grooves are separated from each other by a plurality of teeth arranged in a toothed belt, and each of the plurality of teeth in the toothed belt is separated from each other by a first discontinuous auxiliary chip groove surface portion of a first auxiliary chip groove and a second discontinuous auxiliary chip groove surface portion of a second auxiliary chip groove, wherein the first auxiliary chip groove is consecutively adjacent to the second auxiliary chip groove, wherein a radial peripheral surface of each of the plurality of teeth arranged in the toothed belt defines a facial portion having a perimeter including a first side edge and a second side edge, the first side edge and the second side edge converging to form an apex, the apex being oriented such that the two side edges are open opposite to a cutting rotation direction of the rotary cutting tool, wherein a first side edge of the face portion is formed by an intersection of the face portion and a flute surface of a first primary flute, the first side edge defining a first cutting edge, wherein a second side edge of the face portion is formed by an intersection of the face portion and the first discontinuous auxiliary flute surface portion of the first auxiliary flute, the second side edge defining a second cutting edge, wherein a first region of the facial portion extending from the first cutting edge toward an interior region of the facial portion is non-planar and defines a relief surface of the first cutting edge, and wherein 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 relief surface of the second cutting edge.

2. The rotary cutting tool according to claim 1, wherein: The relief surface of the first cutting edge and the relief surface of the second cutting edge are non-coplanar and merge at a transition feature.

3. The rotary cutting tool according to claim 1 or 2, wherein: The first cutting edge, the second cutting edge and the vertex are located on a surface of an imaginary cylinder having a central axis coinciding with the longitudinal central axis of rotation.

4. The rotary cutting tool according to claim 3, wherein: All other portions of the facial portion are radially inward relative to the surface of the imaginary cylinder.

5. The rotary cutting tool according to any one of claims 1 to 2, wherein: In a cross section through the fluted cutting end portion and perpendicular to the longitudinal center rotation axis, the arc length of the primary flute is greater than the arc length of the auxiliary flute.

6. The rotary cutting tool according to claim 2, wherein: In a cross section through the relief surface of the first cutting edge and perpendicular to the transition feature, the relief surface of the first cutting edge comprises a curved surface having a first radius, wherein, in a cross section 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, and The length of the first radius is the same as the length of the second radius.

7. The rotary cutting tool according to any one of claims 1 to 2, wherein: The helix angle α of each main chip relief groove has an absolute value of 45°<=|α|<=70°.

8. The rotary cutting tool according to claim 7, wherein: The helix angle α of each main chip relief groove has an absolute value of 59°<=|α|<=61°.

9. The rotary cutting tool according to any one of claims 1 to 2, wherein: The helix angle β of each auxiliary chip relief groove has an absolute value of 45°<=|β|<=70°.

10. The rotary cutting tool according to claim 9, wherein: The helix angle β of each auxiliary chip relief groove has an absolute value of 59°<=|β|<=61°.

11. The rotary cutting tool according to claim 9, wherein: The absolute value of the helix angle α of each main chip relief groove is the same as the absolute value of the helix angle β of each auxiliary chip relief groove.

12. The rotary cutting tool according to any one of claims 1 to 2, wherein: Each main chip relief groove has a positive radial rake angle γ of 9°<=γ<=11°.

13. The rotary cutting tool according to claim 12, wherein: Each main chip flute has a positive radial rake angle γ of γ=10°.

14. The rotary cutting tool according to any one of claims 1 to 2, wherein: Each auxiliary chip relief groove has a positive radial rake angle ε of 9°<=ε<=11°.

15. The rotary cutting tool according to claim 14, wherein: Each auxiliary chip relief groove has a positive radial rake angle ε of ε=10°.

16. The rotary cutting tool according to claim 2, wherein: The distance between the transition features of adjacent teeth on a toothed belt determined parallel to the longitudinal center rotation axis defines a pitch, wherein the maximum distance between the first cutting edge and the second cutting edge of the facial portion of one of the adjacent teeth defines a cutting width, and wherein the cutting width is greater than the pitch.

17. The rotary cutting tool according to any one of claims 1 to 2, wherein: The perimeter of the facial portion has a quadrilateral, parallelogram or rhombus shape.

18. The rotary cutting tool according to any one of claims 1 to 2, wherein: Each tooth in a toothed belt of the plurality of toothed belts has the same geometry.

19. The rotary cutting tool according to any one of claims 1 to 2, wherein: The radial depth of the main chip removal groove is greater than the radial depth of the auxiliary chip removal groove.

20. The rotary cutting tool according to any one of claims 1 to 2, wherein: The primary chip flute is a right-handed chip flute, and the secondary chip flute is a left-handed chip flute.

21. A method of removing material from a fiber reinforced composite workpiece, the method comprising: Rotating a rotary cutting tool according to any one of claims 1 to 20, the rotary cutting tool being mounted on a spindle of an apparatus for machining; as well as Material is removed from the workpiece by contacting the first cutting edge and the second cutting edge with the workpiece.

22. The method according to claim 21, wherein: The fiber reinforced composite material is carbon fiber reinforced plastic (CRFP) or glass fiber reinforced plastic (GFRP).

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