Rotary cutting tool with precise coolant flows

Abstract

Rotary cutting tool (10), comprising: an adapter (14) including a guide shaft (22), an internal main coolant channel (34) and a secondary coolant channel (40) extending from the internal main coolant channel (34) to a front end surface (42) of the adapter (14); and a milling cutter (12) attached to the adapter (14), the milling cutter (12) comprising: a cutter body (12, 48) having a plurality of chip flutes (50) and a plurality of bearing surfaces adapted to mount a cutting insert (13) thereon, the cutter body (12, 48) further comprising a guide shaft bore (60) adapted to receive the guide shaft (22) of the adapter (14) and a mounting bore (62) formed in a front end surface (64) of the cutter (12) and adapted to receive a threaded fastener (15); a coolant manifold (66) formed between the guide shaft bore (60) and the mounting bore (62) and in fluid communication with a secondary coolant channel (40) of the adapter (14), the coolant manifold (66) being defined by a cylindrical sidewall (66a) having a width (W) and a bottom surface (66b) intersecting the sidewall (66a) at a circular intersection line (66c), and the coolant manifold (66) extending radially outwardly with respect to the guide shaft bore (60), at least one coolant reservoir (68) in fluid communication with the coolant distributor (66); and a plurality of coolant channels (70a, 70b, 70c) in fluid communication with the at least one coolant reservoir (68) for providing a coolant flow (74a, 74b, 74c) directed to a plurality of specific critical cutting areas of the cutting insert (13), wherein the at least one coolant reservoir (68) has a longitudinal axis located on a circular intersection line (66c) of the coolant distributor (66), wherein the longitudinal axis of the at least one coolant reservoir (68) is oriented at a non-zero angle (A) with respect to a central longitudinal axis of the milling cutter (12), and wherein each coolant channel (70a, 70b, 70c) has a cross-sectional area that is smaller than a cross-sectional area of ​​the at least one coolant reservoir (68).

Description

FIELD OF DISCLOSUREEmbodiments generally relate to cutting tools, and more particularly to a light weight cutting tool, such as a reamer and the like, formed from a composite material including steel, carbon fiber, and the like using additive manufacturing (i.e., 3D printing) to optimize the shape and distribution of the material.BACKGROUND OF THE DISCLOSUREFor example, if one attempts to make a large hole with a reamer, the tool may become very heavy. Heavy tools are problematic for operators who must handle the tools. In addition, the time to accelerate and decelerate the tool to the desired speed decreases with reduced tool weight and moment of inertia. Furthermore, many machines with automatic tool changers also have weight limits for tools that can be changed in the machine. Therefore, there is a need to minimize the weight of large tool holders to allow easier handling and reduced operating costs.DE 10 2017 131 368 A1 discloses a reaming tool comprising: a tool body having an axially rear shaft portion and an axially front cutting portion, the front cutting portion having at least one circumferentially arranged cutting insert; an inlet coolant channel formed in the tool body and defining an inlet opening at an axially rear end of the shaft portion, the inlet coolant channel having a longitudinal axis; an outlet coolant channel formed in the tool body and in fluid communication with the inlet coolant channel, the outlet coolant channel defining an outlet opening proximate the cutting insert, at least a portion of the outlet coolant channel being non-linear.DE 10 2017 209 442 A1 discloses a rotary tool which extends along an axis of rotation in an axial direction, having a carrier which has a coupling receptacle, a cutting head which is inserted into the coupling receptacle, a fastening screw via which the cutting head is braced against the coupling receptacle in the opposite direction to the axial direction, wherein the coupling receptacle has a central pin receptacle having a base surface and having an opposite lateral contact surface a front-side first contact surface, wherein the first contact surface is inclined toward the axis of rotation, wherein the cutting head has a central coupling pin for insertion into the pin receptacle having opposite lateral pin surfaces and having a pin base, a head part which adjoins the coupling pin in the axial direction and has a second contact surface which is inclined toward the axis of rotation, wherein, in the assembled state, the cutting head is braced with its second contact surface against the first contact surface, and the pin bottom simultaneously rests on the bottom surface.Further, from US 3 293 727 A a cutting tool is known comprising: a body; a shank formed at one end of the body for mounting the tool in a holder for a cutting operation; a head at the other end of the body; a cutting tip releasably mounted in the head; the cutting tip having a plurality of outwardly extending blade portions with cutting edges at their leading ends; the cutting tip having an axially longitudinally arranged rib projecting outwardly beyond the sides of the blade portions; a passage formed by the tool and terminating at the cutting tip in the head for directing coolant to the cutting tip; wherein the rib has a coolant chamber formed therein for receiving pressurized coolant from the passage in the tool; and a plurality of laterally spaced forwardly outwardly diverging fluid passages formed in the blade portions for directing coolant from the chamber in the rib and into engagement with a workpiece to be cut and the tool in the cutting area for cooling and removing chips from the working area.WO 2018 / 162 185 A1 discloses a tool tip integral with a tool body or configured to be removably attached thereto and configured to machine a metal object.DE 10 2006 026 967 A1 relates to a method for producing a cutting tool having a tool holder on which a cutting tool is mounted in a detachable manner, wherein a tool base body is produced, which is brought to the finished shape of the tool holder by means of a generative production method.US 4 929 131 A discloses a milling machine for linear machining of metal from a workpiece, the milling machine having means for mounting a cutting tool and feeding it axially into the workpiece to thereby remove material therefrom, the tool mounting means comprising a spindle characterised by an outer tapered annular surface and an axial cavity, the improvement comprising a cutting tool having an axial shank and an inner tapered annular surface, and wherein the tool mounting means comprises means for urging the axial shank into the axial cavity and bringing the tapered surfaces into contact, thereby providing a bearing surface for supporting the tool when the machine is operated. EP 3 150 319 A1 discloses a tool body for a milling tool having a central axis of rotation, with a front end, a rear end having a central recess for engaging a machine, a shroud surface, at least one insert seat in which a cutting insert can be mounted, a chip pocket in front of each insert seat, and a coolant passage system for the passage of coolant from the central recess to each chip pocket, comprising at least one coolant passage having a rear portion extending outward from the central recess and a front portion extending from the rear portion and into the chip pocket in which an outlet is provided, the rear portion being wider than the front portion of the coolant passage.Referring to Figures 11 and 12, a specific embodiment of a conventional milling cutter 120 having replaceable cutting inserts 122 is shown. The milling cutter 120 has a plurality of recesses 124 within the milling cutter body 126. The recesses 124 provide clearance for the attachment of cutting inserts 122 that form the cutting portion of the milling cutter 120 because the cutting edge 128 of the cutting insert 122 at the insert-chip interface, which is the location at which the cutting insert engages the workpiece.Each recess 124 includes a seating surface 132 for seating the corresponding cutting insert 122. The cutting insert 122 is held against the seating surface 132 by means of the retaining screw 134 that is threadably engaged with an opening 136 on the seating surface 132 of the milling cutter body 126. Protruding from the cutter body 126 is the shaft 138, which is operatively connected to a rotary device (not shown). The milling cutter 120 and the rotating device have a common rotation axis illustrated by the dashed line AR-AR in FIG. 11. The shank 138 also provides a path for supplying coolant to the milling cutter 120.Reference is now made to FIG. 12 which shows a cross-sectional view of the milling cutter 120 of FIG. 11 taken along section line 12- 12, i.e., along a centerline of a coolant channel 150 included in the milling cutter body 126. The coolant channel 150 has a diameter "A". The coolant channel 150 provides a passage for the transport of coolant from a centrally located coolant reservoir 152 in the cutter body 126 to the recess 124. The coolant reservoir 152 contains a coolant reservoir. At the outlet end 154 of the coolant passage 150 is a coolant spray nozzle 160 that abuts the recess 124. The coolant passage 150 further includes an inlet end 156 adjacent or proximate to the reservoir 152.Referring to the operation of the specific embodiment of the conventional milling cutter using the coolant spray nozzle 160, the coolant is fed under pressure from a coolant source 112 (shown schematically) into the reservoir 152 from where the coolant flows into and through the coolant passage 50 and into the coolant spray nozzle 60. The coolant flows through the coolant spray nozzle 60 and the coolant exits under pressure in a fan shaped coolant spray 114 which impinges upon the intersection between the cutting edge 128 of the cutting insert 122 and the workpiece 116 and thereby supplies coolant to the insert-chip interface.Unfortunately, due to geometrical constraints, the coolant channel typically has a large diameter and the emerging coolant jet typically targets above the cutting insert and is unable to meet all critical cutting areas of the cutting insert. As a result, the effective cooling of the cutting insert is poor and a relatively large amount of waste coolant is generated.SUMMARY OF THE DISCLOSUREA problem of poor effective cooling and large coolant waste can be solved by forming, for each cutting insert, a coolant reservoir extending from a coolant manifold a predetermined distance from the outer surface of the chip flute. Then, a plurality of coolant holes or channels, each having a relatively smaller cross-sectional area than the coolant reservoir, are formed that extend from the outer surface of the chip flute to a bottom surface of the coolant reservoir, thereby effectively cooling a critical cutting area of the cutting insert and, at the same time, reducing coolant waste.In one aspect, a rotary cutting tool includes an adapter including a guide shaft, a main inner coolant channel, and a secondary coolant channel extending from the main inner coolant channel to a front end surface of the adapter; and a milling cutter attached to the adapter. The milling cutter comprises a milling cutter body having a plurality of flutes and a plurality of seating surfaces configured to mount a cutting insert thereon, the milling cutter body further comprising a guide shaft bore configured to receive the guide shaft bore of the adapter; and a mounting bore formed in a forward end surface of the milling cutter and adapted to receive a threaded fastener. Further, the milling cutter body includes a coolant manifold formed between the guide shaft bore and the mounting bore and in fluid communication with a secondary coolant channel of the adapter. The coolant manifold is defined by a cylindrical sidewall having a width W and a bottom surface intersecting the sidewall at a circular intersection, and wherein the coolant manifold extends radially outward with respect to the guide shaft bore. At least one coolant reservoir is in fluid communication with the coolant manifold. A plurality of coolant passages are in fluid communication with the at least one coolant reservoir to provide a coolant flow directed at a plurality of specific critical cutting areas of the cutting insert. The at least one coolant reservoir has a longitudinal axis located on a circular intersection of the coolant manifold, wherein the longitudinal axis of the at least one coolant reservoir is oriented at a non-zero angle A with respect to a central longitudinal axis of the milling cutter. Furthermore, each coolant channel has a cross-sectional area that is smaller than a cross-sectional area of the at least one coolant reservoir.In another aspect, a rotary cutting tool includes an adapter including a guide shaft, a main inner coolant passage, and a secondary coolant passage extending from the main inner coolant passage to a front end surface of the adapter; and a milling cutter mounted on the adapter. The milling cutter comprises a milling cutter body having a plurality of flutes and a plurality of seating surfaces adapted to mount a cutting insert thereon, the milling cutter body further comprising a guide shaft bore formed in a rear end surface and adapted to receive the guide shaft of the adapter; and a mounting bore formed in a front end surface of the milling cutter and adapted to receive a threaded fastener. Further, the milling cutter body includes a coolant manifold formed between the guide shaft bore and the fastener bore and in fluid communication with a secondary coolant passage of the adapter, wherein the coolant manifold is defined by a cylindrical sidewall having a width W and a bottom surface intersecting the sidewall at a circular intersection, and wherein the coolant manifold extends radially outward with respect to the guide shaft bore. A plurality of coolant reservoirs are in fluid communication with the coolant manifold. A plurality of coolant passages are in fluid communication with each coolant reservoir to provide a coolant flow directed at a plurality of specific critical cutting areas of the cutting insert, the at least one coolant reservoir having a longitudinal axis located on a circular intersection of the coolant manifold. A bottom of each coolant reservoir terminates at a predetermined distance D from each flute of the milling cutter, the predetermined distance D being in a range between about 0.5 mm and about 2.0 mm.In another aspect, a milling cutter includes a milling cutter body having a plurality of flutes and a plurality of seating surfaces adapted to mount a cutting insert thereon. The milling cutter body includes a coolant manifold formed between the guide shaft bore and the fastener bore and in fluid communication with a secondary coolant passage of the adapter, wherein the coolant manifold is defined by a cylindrical sidewall having a width W and a bottom surface intersecting the sidewall at a circular intersection, and wherein the coolant manifold extends radially outward with respect to the guide shaft bore. A coolant reservoir is in fluid communication with the coolant manifold. A plurality of coolant passages are in fluid communication with the coolant reservoir to provide a coolant flow directed at a plurality of specific critical cutting areas of the cutting insert. The coolant reservoir has a longitudinal axis located on a circular intersection of a coolant manifold. Additionally, the coolant reservoir has a longitudinal axis, wherein a longitudinal axis of the coolant reservoir is oriented at a non-zero angle A with respect to a central longitudinal axis of the milling cutter. Further, each coolant channel has a cross-sectional area that is less than the cross-sectional area of each coolant reservoir.BRIEF DESCRIPTION OF THE DRAWINGSWhile various embodiments are illustrated, the particular embodiments shown should not be construed as limiting the claims. It is understood that various changes and modifications may be made without departing from the scope of this disclosure. FIG. 1 is a side view of a rotary cutting tool such as an indexable milling cutter according to an embodiment when mounted on a conical adapter; FIG. 2 is a cross-sectional view of the rotary cutting tool taken along line 2- 2 of FIG. 1 ; FIG. 3 is a side view according to an embodiment of an indexable milling cutter with precise coolant flows directed at critical regions of the cutting insert; FIG. 4 is another side view of the milling cutter according to an embodiment, showing the coolant reservoirs, coolant passages, and outlet ports in phantom; FIG. 5 is a cross-sectional view of the milling cutter along the longitudinal central axis of the milling cutter according to an embodiment showing the guide shaft bore, the mounting bore, the coolant manifold, and the coolant reservoirs in fluid communication with the coolant manifold; FIG. 6 is a rear partial cross-sectional view of the milling cutter according to an embodiment showing the guide shaft bore, the coolant manifold, and the coolant manifolds in fluid communication with the coolant reservoir; FIG. 7 is an enlarged cross-sectional view of the coolant flow path into the adapter guide shaft bore, through the coolant manifold, and into one of the coolant reservoirs of the milling cutter, according to an embodiment; FIG. 8 is a front perspective view of a shoulder milling cutter with precise coolant flows directed toward critical regions of the cutting insert, according to an embodiment; FIG. 9 is another front view of the shoulder milling cutter according to an embodiment, showing the coolant reservoirs, coolant passages, and outlet ports in phantom; FIG. 10 is a rear perspective view of the shoulder milling cutter according to an embodiment, showing the guide shaft bore, the coolant reservoirs, and the coolant passages; FIG. 11 is a perspective view of a conventional indexable milling cutter having coolant spray nozzles; and FIG. 12 is a cross-sectional view of the conventional indexable milling cutter taken along line 12- 12 of FIG. 11.DETAILED DESCRIPTIONReferring to FIGS. 1 and 2, a rotary cutting tool 10 according to an embodiment is shown. Generally, the rotary cutting tool 10 includes a milling cutter 12 having at least one cutting insert 13 mounted thereon and a conical adapter 14, and a threaded fastener 15 may be used to attach the milling cutter 12 to the conical adapter 14. The milling cutter 10 includes a central longitudinal axis (i.e., the z-axis) 17. the central longitudinal axis 17 is generally the axis of rotation of the rotary cutting tool 10. The milling cutter 12 has the threads 20 so that the fastening element 15 can be screwed into the milling cutter 12. The milling cutter 12 can be placed on a stud 22 of the conical adapter 14 and the threaded fastener 15 can be threaded into the conical adapter 14 to secure the milling cutter 12 to the conical adapter 14.In the illustrated embodiment, the rotary cutting tool includes a milling cutter 12 and a conical adapter 14, however, it should be appreciated that principles broadly contemplated herein may be applied to any type of rotary cutting tool, such as a drill rod, a drill bit, and the like. It will also be appreciated that the principles contemplated herein in the broadest sense may be applied to any type of adapter, such as a non-conical, cylindrical, and the like.The directional terms used herein, such as left, right, front, rear, top, bottom, and derivatives thereof, refer to the orientation of the elements shown in the drawings and do not limit the claims unless expressly stated therein. Identical parts are provided with the same reference number throughout the drawings.The approximation language as used throughout the specification and claims herein may be used to modify any quantitative representation that could vary permissibly without resulting in a change in the basic function to which it relates. Accordingly, a value modified by a term or terms such as "about", "approximately", and "substantially" is not intended to be limited to the exact value specified. At least in some cases, the approximation language may correspond to the precision of an instrument for measuring the value. Here and throughout the specification and claims, range boundaries may be combined and / or interchanged and such ranges are identified and include all subareas included therein unless context or language otherwise indicates.Throughout the text and claims, the use of the word "about" in terms of a range of values (e.g., "about 22-35 wt.%") is intended to modify both the high and low values indicated and reflects the penumbra of the variation associated with measurement, meaningful locations, and interoperability, all as understood by one of ordinary skill in the art to which this disclosure pertains.For purposes of this specification (except in the operating examples), unless otherwise stated, all numbers expressing quantities and ranges of constituents, process conditions, etc., are to be understood in all instances as modified by the term "about.". Accordingly, the numerical parameters recited in this specification and the appended claims are approximations that may vary depending on the desired results to be achieved by embodiments. At least, and not as an attempt to limit the application of the equivalence gauge to the scope of the claims, each numerical parameter should be construed at least in light of the number of significant digits specified and by applying ordinary rounding techniques. Furthermore, as used in this specification and the appended claims, the singular forms "a", "an" and "the / s" are intended to include the plural forms unless expressly and unequivocally limited to one form.Regardless of the numerical ranges and parameters that set forth the broad scope being approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Each numerical value, however, basically contains certain errors which are necessarily derived from the standard deviation found in the respective corresponding test measurements, including those found in the measuring instrument. It will also be understood that each numerical range listed herein is intended to include all sub-ranges summarized therein. For example, a range of "1 to 10" is intended to include all sub-ranges therebetween including the listed minimum value of 1 and the listed maximum value of 10, i.e., a range having a minimum value equal to or greater than 1 and a maximum value equal to or less than 10. Unless expressly stated otherwise, the various numerical ranges specified in this application are approximations.In the following specification and claims, reference is made to a number of terms having the following meanings.The singular forms "a", "an" and "the / s" include the plural unless the context clearly dictates otherwise."Optional" means that the subsequently described event or circumstance may or may not occur, and that the description includes examples in which the event occurs and examples in which it does not occur.As used herein, the term "elongated" is defined as what is longer than it is wide. In other words, the width is smaller than the length.The term "circular" as used herein is defined as an object having a shape of a circle, i.e., an object having a simple closed shape. What is meant is the set of points in a plane that are at a certain distance from a certain point, the center; equivalently, it is the curve drawn from a point that moves in a plane such that its distance from a certain point is constant. The distance between any of the points and the center is called the radius.As used herein, the term "fluid" is defined as a substance that is not solid in shape and readily yields under external pressure, such as a gas or a liquid.As used herein, the term "3D printing" is one of various processes in which material is joined or solidified under computer control to produce a three-dimensional object, wherein material, such as liquid molecules or powder grains, that are fused together are usually joined layer by layer. In the 1990s, 3D printing techniques have been considered suitable only for making functional or aesthetic prototypes, and since rapid prototyping has been a more comprehensive term for 3D printing. Today, the precision, repeatability and material spectrum have improved to such an extent that 3D printing is considered an industrial production technology with the official term "additive manufacturing".As used herein, the term "hole" is defined as an opening through what is defined as a gap; a cavity; or an opening that may have any cross-sectional shape.As used herein, the term "critical area of the cutting insert" is defined as an area of the chip / cutting insert interface where coolant is supplied.As used herein, the term "manifold" is defined as a tube or chamber that branches into multiple openings.As used herein, the term "reservoir" is defined as a container or chamber for containing a liquid or fluid.As used herein, the term "conduit" is defined as any tube, conduit, tube, or conduit through which a fluid, air, or other substance is directed or conveyed.Referring to FIGS. 1 and 2, the conical adapter 14 engages a mounting system (not shown) of a machine tool (not shown) as is known. The adapter 14 includes a conical shank portion 24 suitable for engaging the machine tool and a non-conical shank portion 26 having a front end surface 28. The guide shank 22 extends outwardly from the front end surface 28 and is concentric about the central longitudinal axis 17 when the rotary cutting tool 10 is mounted, as shown in FIG. 2. The adapter 14 further includes an intermediate flange 30 for automatically handling the conical adapter 14 disposed between the conical shank portion 24 and the non-conical shank portion 26.For attaching the adapter 14 to the machine tool, a threaded hole 32 may be disposed in a rear end surface 33 of the conical shaft portion 24. As shown, conical adapter 14 is a CV adapter manufactured by Kennametal Inc. However, it should be understood that adapter 14 may be of any type known to those of ordinary skill in the art suitable for mounting a rotary tool to a machine tool, such as DV, BT or KM type adapters manufactured by Kennametal Inc., CAPTO (Coromant) type adapters, or HSK type adapters.In the illustrated embodiment, the conical adapter 14 includes an inner main coolant passage 34 that extends through the adapter 14 for supplying a flow of fluid, such as coolant and the like, from the machine tool to the milling cutter 12. An annular secondary coolant passage 40 disposed within the guide shaft 22 is in fluid communication with the main inner coolant passage 34. the secondary coolant passage 40 extends from the main inner coolant passage 34 to a front end surface 42 of the guide shaft 22. Additionally, the conical adapter 14 includes a pair of round drive pins 44, 46 disposed on and extending from the front surface 28.In the illustrated embodiment of Figs. 1 and 2, a total of five (5) cutting inserts 13 are mounted on the cutting body 12 of the rotary cutting tool 10. As is known, the cutting inserts 13 are indexable. The milling cutter 12 is therefore also known as an indexable insert milling cutter. Further, it should be understood that the embodiments are not limited by the number of cutting inserts 13 mounted on the cutter body 12, and that the principles contemplated herein in the broadest sense may be applied to a cutter body 12 on which any desired number of cutting inserts 13 may be isometrically and / or tangentially mounted.As shown in FIGS. 3 and 4, the milling cutter 12 includes a cutter body 48 having a plurality of flutes 50 formed therein. The flutes 50 provide clearance for inserting the cutting inserts 13 and assist in the removal of chips generated during a cutting operation. In the illustrated embodiment, the cutting inserts 13 are replaceable indexable inserts made in whole or in part, for example and without limitation, of cemented carbides (e.g., tungsten (cobalt) cemented carbide, which may optionally contain additions of titanium carbide, tantalum carbide, and / or niobium carbide, ceramics (e.g., alumina, silicon aluminum oxynitride (SiAlON), superhard materials (e.g., cubic boron nitride), and cermets (e.g., titanium carbide-based materials). The milling cutter 12 is therefore also known as an indexable insert milling cutter. Each cutting insert 13 includes one or more major cutting edges 13a that engage the workpiece (not shown) at the insert-chip interface. Furthermore, each cutting insert 13 comprises one or more cutting corners 13 band one or more scraping facets 13 c.In the illustrated embodiment, each cutting insert 13 is polygonal with a total of five (5) major cutting edges 13a, cutting corners 13b and scraping facets 13c. Therefore, each cutting insert 13 can be indexed by rotating the cutting insert 13 about 72 degrees about its central axis so that during a cutting operation, another major cutting edge 13a engages the workpiece. However, it should be appreciated that embodiments are not limited by the number of major cutting edges, scraper facets, and cutting corners, and that embodiments may be practiced with a cutting insert having any desired number of major cutting edges, scraper facets, and cutting corners. The cutting insert 13 may be, for example, triangular, rectangular, hexagonal, octagonal, and the like. In another example, the cutting insert 13 may be round and have only a single major cutting edge 13 aand an optional scraping facet 13 c, and the cutting corner 13 bmay be eliminated.A support surface 52 is provided near each chip flute 50 for supporting the corresponding cutting insert 13. As is known, the cutting insert 13 is held against the support surface 52 by means of a retaining screw 53 (FIG. 9 ) which is in threaded engagement with an opening 55 (FIG. 5 ) formed in the support surface 52 of the milling cutter body 48. A shank 54 extends rearwardly outwardly so that the cutter 12 can be operatively attached to the adapter 14 as described above. The shaft 54 includes one or more drive pin recesses 56 adapted to receive a corresponding drive pin 44, 46 of the adapter 14. The recesses 56 are formed in a rear end surface 58 of the milling cutter 12, as shown in FIG. 5. When the milling cutter 12 is attached to the adapter 14, the milling cutter 12 and the adapter 14 share a common rotational axis (i.e., collinear) with the central longitudinal axis 17 of the rotary cutting tool 10, as shown in FIG. 2.Referring to FIG. 5, the bur 12 includes a guide shaft bore 60 formed in the rear end surface 58 of the bur 12 and adapted to receive the guide shaft 22 of the adapter 14. The milling cutter 12 also includes a mounting bore 62 formed in a front end surface 64 of the milling cutter 12 and adapted to receive the threaded fastener 15.A coolant manifold 66 is formed between the guide shaft bore 60 and the fastener bore 62. The coolant manifold 66 is defined by a cylindrical side wall 66a having a width W and a substantially planar bottom surface 60b intersecting the side wall 66a at a circular intersection line 66c as shown in Figs. 5-7.In one aspect, the milling cutter 12 includes a plurality of coolant reservoirs 68 in fluid communication with the coolant manifold 66, as shown in FIGS. 2 and 4-7. In particular, there is a one-to-one correspondence between the number of cutting inserts 13 and the number of reservoirs 68. In other words, the number of coolant reservoirs 68 is equal to the number of cutting inserts 13. Thus, in the illustrated embodiment, there are a total of five (5) coolant reservoirs 68 (i.e., one coolant reservoir 68 for each cutting insert 13) that are in fluid communication with the coolant manifold 66. It should be understood, however, that the invention is not limited by the number of coolant reservoirs 68, and that the invention may be practiced with a different number of coolant reservoirs 68 than the number of cutting inserts 13. For example, it is envisioned that the principles of the disclosure may be practiced with a single coolant reservoir 68 disposed up to about 360 degrees around the axis of rotation AR of the milling cutter 12 as long as the cutting head 12 has sufficient structural integrity.As best shown in FIG. 6, the coolant reservoirs 68 are equi-spaced about the central longitudinal axis 17 of the milling head 12. In the illustrated embodiment, each of the five coolant reservoirs 68 is equidistant from one another about the central longitudinal axis 17 of the milling head 12 of about 72 degrees (i.e., 360 / 5). As shown in FIG. 6, each coolant reservoir 68 is in fluid communication with the coolant manifold 66. in particular, each coolant reservoir 68 is formed along the circular intersection 66 cbetween the cylindrical side surface 66 aand the bottom surface 66 bof the coolant manifold 66.Further, each coolant reservoir 68 is oriented at a non-zero angle A with respect to the central longitudinal axis 17 of the milling cutter 12, as shown in FIG. 5. In one embodiment, each coolant reservoir 68 is oriented at an angle A between about 15 degrees and about 65 degrees depending on the dimensions of the milling cutter 12. Each coolant reservoir 68 has a central longitudinal axis C L intersecting at a point P on the central longitudinal axis 17 of the milling cutter 12. In addition, each coolant reservoir 68 has a curved bottom surface 68 aas shown in FIG. 4.Referring to FIG. 5, each coolant reservoir 68 may be manufactured by machining a cavity from the guide shaft bore 60 toward the seating surface 52 of a corresponding cutting insert 13 and ending at a predetermined distance D from the chip flute 50. In other words, the bottom 68 aof each coolant reservoir 68 terminates at the predetermined distance D from the flute 50. in one embodiment, the distance D is between about 0.5 mm to about 2.0 mm. The distance D may be, for example, about 1.0 mm. The cavity may be machined using conventional CNC machining methods using a ball end mill, a drill, or a combination of both.In addition, each coolant reservoir 68 has a non-circular cross-sectional shape, as shown in FIGS. 5 and 6. Each coolant reservoir 68 has, for example, an elongated or elliptical cross-sectional shape. However, it should be understood that the embodiments are not limited by the cross-sectional shape of each coolant reservoir, and that embodiments may be practiced with one or more coolant reservoirs having a circular cross-sectional shape and one or more coolant reservoirs 68 having a non-circular cross-sectional shape.In another aspect, the bur 12 includes a plurality of coolant passages 70 disposed within the bur body 48, as shown in FIG. 4. In the illustrated embodiment, the milling cutter body 48 includes three coolant passages 70 a, 70 b, 70 cin fluid communication with a corresponding coolant reservoir 68. Each coolant channel 70 a, 70 b, 70 cextends from its corresponding coolant reservoir 68 to a corresponding outlet opening 72 a, 72 b, 72 cin the flute 50 proximate a corresponding cutting insert 13.Each coolant passage 70 a, 70 b, 70 cgenerates a directed coolant flow 74 a, 74 b, 74 cfrom its corresponding outlet opening 72 a, 72 b, 72 c. Thus, in the illustrated embodiment, the milling cutter 12 generates a total of three (3) coolant streams directed to different critical cutting areas of the cutting insert 13. For example, the coolant channel 70 agenerates a coolant flow 74 adirected to the major cutting edge 13 aof the cutting insert 13, the coolant channel 70 bgenerates a coolant flow 74 bdirected to the cutting corner 13 bof the cutting insert 13, and the coolant channel 70 cgenerates a coolant flow 74 cdirected to the scraping facet 13 cof the cutting insert 13, as shown in FIGS. 3 and 4.Each coolant passage 70 a, 70 b, 70 cand each outlet opening 72 a, 72 b, 72 cmay be formed by forming a hole extending from the chip flute 50 to its corresponding coolant reservoir 68. Therefore, both the coolant reservoir 68 and the coolant passages 70 a, 70 b, 70 cmay be formed using conventional CNC machining methods using a ball end mill, a drill, or a combination of both without bottleneck. In the illustrated embodiment, the coolant passages 70 a, 70 b, 70 chave a substantially circular cross-sectional shape. However, it should be appreciated that embodiments are not limited by the cross-sectional shape of the coolant passages, and that embodiments may be practiced with coolant passages having a non-circular cross-sectional shape.Each coolant channel 70 a, 70 b, 70 cmay have a diameter in a range between about 0.5 mm to about 5.0 mm. The coolant passages 70 a, 70 b, 70 cmay have the same diameter. Each coolant channel 70 a, 70 b, 70 cmay have a diameter of about 1.0 mm, for example. Alternatively, one or more coolant passages may have a different diameter. For example, one coolant channel may have a diameter of about 1.0 mm and another coolant channel may have a diameter of about 1.5 mm. In either case, each coolant passage 70 a, 70 b, 70 chas a smaller cross-sectional area than the cross-sectional area of the coolant reservoirs 68, thereby increasing the coolant pressure.In addition, the total cross-sectional area of the coolant passages 70 a, 70 b, 70 ccomprises a smaller total cross-sectional area than the total cross-sectional area of the coolant reservoir 68. As a result, the milling cutter 12 uses less coolant than a single coolant channel having a relatively larger cross-sectional area. For example, if the three coolant passages 70 a, 70 b, 70 chave a diameter of 1.0 mm, then the total cross-sectional area is less than a single coolant passage having a diameter of 3.0 mm (i.e., three times the diameter of each of the three coolant passages 70 a, 70 b, 70 c).In the case of three coolant passages having a diameter of 1.0 mm, the total cross-sectional area is as follows:In the case of a single coolant channel having a diameter of 3.0 mm, the total cross-sectional area is as follows:Therefore, the total cross-sectional area for three coolant passages 70 a, 70 b, 70 c, each passage having a diameter of 1.0 mm, is smaller than the total cross-sectional area of a single coolant passage having a diameter of 3.0 mm. As a result, the milling cutter 12 having three coolant passages uses less coolant than a conventional cutting tool having only a single relatively larger coolant passage.In the case of three coolant passages 70 a, 70 b, 70 chaving a diameter of 1.5 mm, the total cross-sectional area is still smaller than a single coolant passage having a diameter of 3.0 mm (i.e., twice the diameter of each of the three coolant passages 70 a, 70 b, 70 c).In the case of three coolant passages having a diameter of 1.5 mm, the total cross-sectional area is as follows:In the case of a single coolant channel having a diameter of 3.0 mm, the total cross-sectional area is as follows:Therefore, the total cross-sectional area for three coolant passages 70a, 70b, 70c, each passage having a diameter of 1.5 mm, is still smaller than the total cross-sectional area of a single coolant passage having a diameter of 3.0 mm. As a result, the milling cutter 12 having three coolant passages uses less coolant than a conventional cutting tool having only a single relatively larger coolant passage.As shown in FIG. 2, a flow F of fluid, such as coolant and the like, enters the main coolant passage 34 formed in the rear end surface 33 of the conical adapter 14. Then, the coolant flows from the inner main coolant passage 34 into the annular secondary coolant passage 40 disposed in the guide shaft 22, through a corresponding coolant reservoir tank 68, into the coolant passages 70 a, 70 b, 70 c. Then, the coolant exits from the outlet ports 72 a, 72 b, 72 cin the coolant streams 74 a, 74 b, 74 c, which are directed precisely to critical regions such as the main cutting edge 13 a, the cutting corner 13 band the scraping facet 13 cof the cutting insert 13.It should be appreciated that embodiments are not limited by the number of coolant passages, and that embodiments may be practiced with any number of multiple coolant passages. In other words, embodiments may be practiced with any number of two or more coolant passages depending on the number of critical cutting areas to which the coolant passages should be directed.The principles may be practiced, for example, in a rotary cutting tool 10 that includes a shoulder mill having four coolant passages 70 a- dand four outlet ports 72 a- dwhich generate a total of four coolant streams 74 a- ddirected to critical regions of the cutting insert 13, as shown in FIGS. 8 and 9. It should be understood that the coolant reservoirs 68 and the coolant passages 70a-d in the embodiment shown in Figures 8 and 9 are made in a similar manner to the coolant reservoirs 68 and the coolant passages 70a, 70b, 70c of the prior embodiment shown in Figures 1-7.In the illustrated embodiment of FIGS. 8 and 9, the coolant channel 70 agenerates a coolant flow 74 afrom the outlet opening 72 adirected to a first portion of the major cutting edge 13 aof the cutting insert 13, the coolant channel 70 bgenerates a coolant flow 74 bdirected to the cutting corner 13 bof the cutting insert 13, the coolant channel 70 cgenerates a coolant flow 74 cdirected to the scraping facet 13 cof the cutting insert 13, and the coolant channel 70 dgenerates a coolant flow 74 dfrom the outlet opening 72 ddirected to a second portion of the major cutting edge 13 a.It should also be noted that the four coolant passages 70 a- dhave a smaller cross-sectional area and therefore use less coolant than a conventional cutting tool having a single coolant passage with a relatively larger diameter. For example, if one coolant channel has a diameter of 1.0 mm and three coolant channels have a diameter of 1.5 mm, then the cross-sectional area is smaller than a single coolant channel having a diameter of 3.5 mm.In the case where one coolant channel has a diameter of 1.0 mm and three coolant channels have a diameter of 1.5 mm:In the case of a single coolant channel with a diameter of 3.5 mm,Therefore, the total area for four coolant passages in which one coolant passage has a diameter of 1.0 mm and three coolant passages have a diameter of 1.5 mm is still smaller than a single coolant passage having a diameter of 3.5 mm. As a result, the cutting tool uses less coolant than a conventional cutting tool having a single, larger coolant channel.As described above, the rotary cutting tool 10 has a novel cooling technology with the following advantages:1) effective cooling with less coolant consumption;2) increased coolant pressure;3) a plurality of accurately aligned coolant streams per chip flute; and4) Practical and economical production process without bottleneck.While the presently preferred embodiments are described, the disclosure may be otherwise embodied within the scope of the appended claims.

Claims

A rotary cutting tool (10) comprising: an adapter (14) including a guide shaft (22), an internal main coolant channel (34), and a secondary coolant channel (40) extending from the internal main coolant channel (34) to a front end surface (42) of the adapter (14); and a milling cutter (12) secured to the adapter (14), the milling cutter (12) comprising: a milling cutter body (12, 48) having a plurality of flutes (50) and a plurality of seating surfaces adapted to attach a cutting insert (13) thereto, the milling cutter body (12, 48) further comprising a guide shaft bore (60) adapted to receive the guide shaft (22) of the adapter (14) and a mounting bore (62) formed in a front end surface (64) of the milling cutter (12) and adapted to receive a threaded fastener (15); a coolant manifold (66) formed between the guide shaft bore (60) and the mounting bore (62) and in fluid communication with a secondary coolant passage (40) of the adapter (14), the coolant manifold (66) being defined by a cylindrical sidewall (66a) having a width (W) and a bottom surface (66b) intersecting the sidewall (66a) at a circular intersection line (66c), and the coolant manifold (66) extending radially outward with respect to the guide shaft bore (60), at least one coolant reservoir (68) in fluid communication with the coolant manifold (66); and a plurality of coolant passages (70a, 70b, 70c) in fluid communication with the at least one coolant reservoir (68) for providing a coolant flow (74a, 74b, 74c) directed at a plurality of specific critical cutting areas of the cutting insert (13), wherein the at least one coolant reservoir (68) has a longitudinal axis located on a circular intersection line (66c) of the coolant manifold (66), wherein the longitudinal axis of the at least one coolant reservoir (68) is oriented at a non-zero angle (A) with respect to a central longitudinal axis of the milling cutter (12), and wherein each coolant passage (70a, 70b, 70c) has a cross-sectional area that is less than a cross-sectional area of the at least one coolant reservoir (68).The rotary cutting tool (10) of claim 1, wherein a total number of coolant reservoirs (68) is equal to a total number of cutting inserts (13).The rotary cutting tool (10) of claim 1, wherein a plurality of coolant reservoirs (68) are disposed at equal intervals about the central longitudinal axis of the milling cutter (12).The rotary cutting tool (10) of claim 1, wherein the milling cutter (12) comprises a shoulder milling cutter.The rotary cutting tool (10) of claim 1, wherein the secondary coolant channel (40) is annular in cross-sectional shape.The rotary cutting tool (10) of claim 1, wherein a bottom (68a) of the at least one coolant reservoir (68) terminates at a predetermined distance D from each flute (50) of the milling cutter (12).The rotary cutting tool (10) of claim 6, wherein the predetermined distance D is in a range between about 0.5 mm and about 2.0 mm.The rotary cutting tool (10) of claim 1, wherein each coolant reservoir (12) has a non-circular cross-sectional shape.The rotary cutting tool (10) of claim 1, wherein the plurality of specific critical cutting regions comprise at least two of a major cutting edge (13a), a cutting corner (13b) and a scraping facet (13c) of the cutting insert (13).A rotary cutting tool (10) comprising: an adapter (14) including a guide shaft (22), a main internal coolant channel (34), and a secondary coolant channel (40) extending from the main internal coolant channel (34) to a front end surface (42) of the adapter (14); and a milling cutter (12) secured to the adapter (14), the milling cutter (12) comprising: a milling cutter body (12, 48) having a plurality of flutes (50) and a plurality of seating surfaces adapted to attach a cutting insert (13) thereto, the milling cutter body (12, 48) further comprising a guide shaft bore (60) formed in a rear end surface and adapted to receive the guide shaft (22) of the adapter (14); and a mounting bore (62) formed in a front end surface (64) of the milling cutter (12) and adapted to receive a threaded fastener (15); a coolant manifold (66) formed between the guide shaft bore (60) and the fastener bore (62) and in fluid communication with a secondary coolant passage (40) of the adapter (14), the coolant manifold (66) being defined by a cylindrical sidewall (66a) having a width (W) and a bottom surface (66b) intersecting the sidewall (66a) at a circular intersection line (66c), and the coolant manifold (66) extending radially outward with respect to the guide shaft bore (60), a plurality of coolant reservoirs (68) in fluid communication with the coolant manifold (66); and a plurality of coolant passages (70a, 70b, 70c) in fluid communication with each coolant reservoir (68) for providing a coolant flow (74a, 74b, 74c) directed at a plurality of specific critical cutting areas of the cutting insert (13), the at least one coolant reservoir (68) having a longitudinal axis located on a circular intersection line (66c) of the coolant manifold (66), wherein a bottom (68a) of each coolant reservoir (68) terminates at a predetermined distance D from each flute (50) of the milling cutter (12), and wherein the predetermined distance D is in a range between about 0.5 mm and about 2.0 mm.The rotary cutting tool (10) of claim 10, wherein each coolant reservoir (68) has a longitudinal axis, and wherein a longitudinal axis of each coolant reservoir (68) is oriented at a non-zero angle (A) with respect to a central longitudinal axis of the milling cutter (12)The rotary cutting tool (10) of claim 10, wherein each coolant reservoir (68) has a cross-sectional area and wherein each coolant channel (70a, 70b, 70c) has a cross-sectional area that is less than the cross-sectional area of each coolant reservoir (68).The rotary cutting tool (10) of claim 10, wherein a total number of coolant reservoirs (68) is equal to a total number of cutting inserts (13).The rotary cutting tool (10) of claim 10, wherein the plurality of coolant reservoirs (68) are equi-spaced about a central longitudinal axis of the milling cutter (12).A milling cutter (12) comprising a cutter body (12, 48) having a plurality of flutes (50) and a plurality of seating surfaces adapted for mounting a cutting insert (13) thereon, wherein the cutter body (12, 48) includes a coolant manifold (66) formed between the guide shaft bore (60) and the fastener bore (62) and in fluid communication with a secondary coolant passage (40) of the adapter (14), wherein the coolant manifold (66) is defined by a cylindrical sidewall (66a) having a width (W) and a bottom surface (66b) intersecting the sidewall (66a) at a circular intersection line (66c), and wherein the coolant manifold (66) extends radially outward with respect to the guide shaft bore (60), a coolant reservoir (68) in fluid communication with the coolant manifold (66), and a plurality of coolant passages (70a, 70b, 70c) in fluid communication with the coolant reservoir (68) to provide a coolant flow (74a, 74b, 74c) directed at a plurality of specific critical cutting areas of the cutting insert (13), wherein the coolant reservoir (68) has a longitudinal axis located on a circular intersection line (66c) of the coolant manifold (66), wherein the coolant reservoir (68) has a longitudinal axis, and wherein the longitudinal axis of the coolant reservoir (68) is oriented at a non-zero angle (A) with respect to a central longitudinal axis of the milling cutter (12), and wherein each coolant reservoir (68) has a cross-sectional area, and wherein each coolant channel (70a, 70b, 70c) has a cross-sectional area that is less than the cross-sectional area of each coolant reservoir (68).The milling cutter (12) of claim 15, further comprising a plurality of coolant reservoirs (68), and wherein the plurality of coolant reservoirs (68) are equi-spaced about the central longitudinal axis of the milling cutter (12).The bur (12) of claim 15, wherein the bur (12) comprises a shoulder bur.The bur (16) of claim 15, wherein the bottom (68a) of each coolant reservoir (68) terminates at a predetermined distance D from each flute (50) of the bur (12) in a range between about 0.5 mm and about 2.0 mm.The milling cutter (16) of claim 15, wherein the coolant reservoir (68) has a non-circular cross-sectional shape.The milling cutter (16) of claim 15, wherein the plurality of specific critical cutting regions comprise at least two of a major cutting edge (13a), a cutting corner (13b) and a scraping facet (13c) of the cutting insert (13c).

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