Lightweight cutting tool

A lightweight cutting tool, such as a reamer, includes a front cutting body, a front cutting ring, a center tube, a rear cutting ring and a rear machine connection member. An arm assembly of the front and rear cutting heads includes one or more leading arms, one or more trailing arms and a cutting head supported by the leading and trailing arms. The leading arms and the trailing arms curve in opposite directions. To reduce weight and moment of inertia of the reamer, a cross-sectional area of the leading arms and the trailing arms is largest proximate the sleeve member and is smallest proximate the cutting head. In addition, the front cutting body, the front and rear cutting rings and the center tube may be made by additive manufacturing. Fluid can be transported entirely through the reamer to the cutting insert/workpiece interface and the guide pad/workpiece interface.

FIELD OF THE INVENTION

In general, the invention relates to cutting tools, and more particularly, to a lightweight cutting tool, such as a reamer, and the like, made of a composite material, including steel, carbon fiber, and the like, using additive manufacturing (i.e., 3D printing) to optimize the shape and distribution of material.

BACKGROUND OF THE INVENTION

When trying to use a reamer to finish a large hole, for example, the tool can become very heavy. Heavy tools are problematic for operators who have to handle the tools. In addition, the time to accelerate and decelerate the tool to its desired speed decreases with reduced tool weight and moment of inertia. Further, many machines with automatic tool changers also have weight limits for tools the machine can changed. Thus, there is a need to minimize the weight of large toolholders to allow for easier handling and reduced operating costs.

SUMMARY OF THE INVENTION

The problem of reducing the weight of a large cutting tool, such as a reamer, and the like, is solved by using additive manufacturing, along with composite materials, including, but not limited to, steel, carbon fiber, and the like, to allow the overall weight of the large cutting tool to be drastically reduced, while optimizing the shape and distribution of material and maintaining the strength, stiffness, and functionality of the cutting tool.

In one aspect, a cutting tool comprises a rear machine connection member; a center tube having a front end and a rear end. At least one cutting ring secured to the center tube and includes a sleeve member and one or more arm assemblies. Each arm assembly includes one or more leading arms extending radially outwardly from the sleeve member, one or more trailing arms extending radially outwardly from the sleeve member. The cutting head is supported by the one or more leading arms and the one or more trailing arms. A cross-sectional area of the one or more leading arms is largest proximate the sleeve member and is smallest proximate the cutting head to reduce weight and moment of inertia of the cutting tool, and a cross-sectional area of the one or more trailing arms is largest proximate the sleeve member and is smallest proximate the cutting head to reduce weight and moment of inertia of the cutting tool.

In another aspect, a cutting tool comprises a rear machine connection member; a center tube having a front end and a rear end. At least one cutting ring secured to the center tube and includes a sleeve member and one or more arm assemblies. Each arm assembly includes one or more leading arms extending radially outwardly from the sleeve member, one or more trailing arms extending radially outwardly from the sleeve member, and the cutting head supported by the one or more leading arms and the one or more trailing arms. The one or more leading arms extend radially outward from the sleeve member with a radius of curvature, RL, and the one or more trailing arms extend radially outward from the sleeve member with a radius of curvature, RT. The one or more leading arms curve in an opposite vertical and horizontal direction than the one or more trailing arms.

DETAILED DESCRIPTION OF THE INVENTION

Referring now toFIGS. 1 and 2, a cutting tool10is shown according to an embodiment of the invention. In the illustrated embodiment, the cutting tool comprises a reamer that rotates in the direction, R, about a central, rotational axis, RA, during operation. Although the large cutting tool10comprises a reamer in the illustrated embodiment, it should be appreciated that the principles of the invention can be applied to any large cutting tool for metal cutting operations, such as a milling cutter, and the like. In addition, the description herein of specific applications should not be a limitation on the scope and extent of the use of the cutting tool.

Directional phrases used herein, such as, for example, left, right, front, back, top, bottom and derivatives thereof, relate to the orientation of the elements shown in the drawings and are not limiting upon the claims unless expressly recited therein. Identical parts are provided with the same reference number in all drawings.

Throughout the text and the claims, use of the word “about” in relation to a range of values (e.g., “about 22 to 35 wt %”) is intended to modify both the high and low values recited, and reflects the penumbra of variation associated with measurement, significant figures, and interchangeability, all as understood by a person having ordinary skill in the art to which this invention pertains.

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

Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements including that found in the measuring instrument. Also, it should be understood that any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, a range of “1 to 10” is intended to include all sub-ranges between and including the recited minimum value of 1 and the recited maximum value of 10, i.e., a range having a minimum value equal to or greater than 1 and a maximum value of equal to or less than 10. Because the disclosed numerical ranges are continuous, they include every value between the minimum and maximum values. Unless expressly indicated otherwise, the various numerical ranges specified in this application are approximations.

In the following specification and the claims, a number of terms are referenced that have the following meanings.

As used herein, the term “elongate” is defined as something that is longer than it is wide. In other words, the width is smaller than its length.

As used herein, the term “circular” is defined as an object having a shape of a circle, i.e., an object having a simple closed shape. It is the set of points in a plane that are at a given distance from a given point, the center; equivalently it is the curve traced out by a point that moves in a plane so that its distance from a given 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 has no fixed shape and yields easily to external pressure, such as a gas or a liquid.

As used herein, the term “3D printing” is any of various processes in which material is joined or solidified under computer control to create a three-dimensional object, with material being added together, such as liquid molecules or powder grains being fused together, typically layer by layer. In the 1990s, 3D printing techniques were considered suitable only to the production of functional or aesthetical prototypes and, back then, a more comprehensive term for 3D printing was rapid prototyping. Today, the precision, repeatability and material range have increased to the point that 3D printing is considered as an industrial production technology, with the official term of “additive manufacturing”.

As used herein, the term “hole” is defined as an opening trough something; a gap; a cavity or an aperture that can have any cross-sectional shape.

As used herein, the term “large” is defined as a cutting tool having a cutting diameter of at least 150 mm.

Referring now toFIGS. 1 and 2, the lightweight reamer10has five basic components:1) a front cutting body12;2) a front cutting ring14;3) a center tube16;4) a rear cutting ring18; and5) a rear machine connection member20. The five basic components can be fastened to each other by using any well-known means in the art, such as shrink fitting, brazing, soldering, welding, glue, epoxy, and the like. Alternatively, all five basic components can be integrally formed using additive manufacturing (i.e., 3D printing).

Referring now toFIGS. 3 and 4, the front cutting body12includes a front cutting portion21and a rear shank portion23. The front cutting body12can be mounted to the center tube16by inserting the rear shank portion23into the center tube16. However, the invention is not limited by the fastening method in which the front cutting body12is attached to the remainder of the reamer10, and that the invention can be practiced using any suitable fastening method for attaching the front cutting body12to the remainder of the reamer10. For example, the shank portion23of the front cutting body12can be omitted, and the flange25can attach directly attach the front cutting body12to be remainder of the reamer10by bolting, riveting, and the like. In another example, the front cutting body12can be made integral with the center tube16.

In the illustrated embodiment, the front cutting portion21is separated from the rear shank portion23by a flange25that cooperates with a flange30on the front cutting ring14to attach the front cutting ring14to the front cutting body12, as shown inFIGS. 2 and 3. The cutting head has a plurality of cutting inserts22mounted in a respective insert pocket26and a plurality of guide pads24mounted in a respective pad pocket28. In the illustrated embodiment, the front cutting body12of the reamer10has a total of four cutting inserts22and four optional guide pads24. However, it will be appreciated that the invention is not limited by the number of cutting inserts22and guide pads24, and that the invention can be practiced with any desirable number of cutting inserts22and guide pads24, such as two, three, five, six, seven, eight, nine, ten, eleven, twelve, and the like. In addition, the guide pads24are optional and can be eliminated. The front cutting body12also includes a port27for providing fluid to the cutting insert22and a port29for providing fluid to the guide pad24.

The front cutting body12shown inFIGS. 3 and 4can be made of tool steel using a conventional machining process. To further reduce the weight of the reamer10, a front cutting body120can be made by additive manufacturing (i.e., 3D printing), as shown inFIGS. 5 and 6. In this embodiment, the front cutting body120is similar to the front cutting body20, except that the front cutting body120does not have the rear shank portion23, further reducing the weight of the front cutting body120, as compared to the front cutting body20. Further, the front cutting body120includes a plurality of chip grooves122separated by ribs124to assist in the evacuation of chips generated during a cutting operation.

It will be appreciated that the invention is not limited by the configuration of front cutting body12,120, and that the invention can be practiced with any desirable configuration that enables the reamer10to machine any desirable material. For example, the invention can be practiced with a front cutting body that includes a plurality of blades separated by flutes (not shown), instead of the cutting inserts22and the guide pads24.

Referring now toFIGS. 7 and 8, the front cutting ring14is shown according to an embodiment of the invention. It should be noted that the front cutting ring14is substantially identical to the rear cutting ring18, except that the rear cutting ring18does not include the flange30and that the rear cutting ring18may have a larger cutting diameter. Therefore, only the front cutting ring14will be described herein for brevity. Thus, it will be appreciated that any description herein for the front cutting ring14also applies to the rear cutting ring18. It should also be noted that the invention is not limited by the number of cutting rings, and that the invention can be practiced with only a single cutting ring, or more than two cutting rings.

In general, the front cutting ring14includes a sleeve member32, one or more leading arms34extending radially outwardly from the sleeve member32, and one or more trailing arms36extending radially outwardly from the sleeve member32. In the illustrated embodiment, the front cutting ring14has an upper leading arm34a, a lower leading arm34b, an upper trailing arm36aand a lower trailing arm36b. Thus, the illustrated embodiment has a total of two leading arms34a,34band a total of two trailing arms36a,36b.

In the illustrated embodiment, the flange30of the sleeve member32cooperates with the flange25of the front cutting body12to secure the front cutting ring14to the front cutting body12. However, it will be appreciated that the front cutting body12can be eliminated, and that the front cutting ring14is secured to the center tube16, similar to the rear cutting ring18, as shown inFIG. 2.

As shown inFIGS. 7 and 8, each leading arm34a,34bdoes not extend in a radial direction from the sleeve member32in a linear fashion, but in a curved fashion with a radius of curvature, RL. Similarly, each trailing arm36a,36bextends in a curved fashion from the sleeve member32with a radius of curvature, RT. The radius of curvature, RL, can be same or different in magnitude than the radius of curvature, RT. In addition, each leading arm34a,34bis curved in an opposite direction with respect to each trailing arm36a,36b. Specifically, the trailing arms36curve in the same direction as the direction of rotation, R, (indicated by the arrow) of the reamer10, and the leading arms34curve in the opposite direction as the direction of rotation, R, of the reamer10.

In addition, each leading arm34a,34band each trailing arm36a,36bsweep along a helical arc defining a helix angle, HA, with respect to the central, rotational axis, RA, as shown inFIG. 7. The helix angle, HA, can be constant or variable. The helix angle, HA, can be in a range between about 0 degrees and about 60 degrees. For example, the helix angle, HA, can be about 35 degrees.

It should be noted that the helix angle, HA, of the leading arms34may be the same magnitude or a different magnitude than the helix angle, HA, of the trailing arms36. For example, the leading arms34may have a smaller helix angle, HA, than the trailing arms36. Also, it should be noted that the trailing arms36spiral in an opposite direction than the leading arms34, as shown inFIG. 7. Thus, both the leading arms34and the trailing arms36curve in opposite directions with respect to both the horizontal axis (i.e., X-direction or Y-direction) and the vertical axis (i.e., Z-direction). The lower leading arm34bis connected to the sleeve member32below the cutting head38. Oppositely, the upper trailing arm36ais connected to the sleeve member32above the cutting head38, as shown inFIG. 7. Thus, the leading arms34curve in an opposite, vertical and horizontal direction as the trailing arms36.

Each of the leading arms34and each of the trailing arms36can be supported by at least one support member46spanning between each leading arm34a,34band each trailing arm36a,36b. The support member46helps maintain the spatial relationship between each leading arm34a,34band each trailing arm36a,36b. In addition, the support member46increases the axial and tangential stiffness of the arm assembly44. In the illustrated embodiment, the support member46is located approximately halfway between the sleeve member32and the cutting head38. However, it will be appreciated that the support member46can be located at any appropriate location that suitably maintains the spatial relationship between the arms34,36.

As shown inFIGS. 7 and 8, the one or more leading arms34, the one or more trailing arms36, and the cutting head38comprise an arm assembly44. In the illustrated embodiment, the reamer10has a total of six arm assemblies44spaced apart from each other about the perimeter of the sleeve member32. In the illustrated embodiment, the arm assemblies44are generally equally spaced about the perimeter of the sleeve member32. However, it should be appreciated that the arm assemblies44can be unequally spaced about the perimeter of the sleeve member32. In addition, the invention is not limited by the number of arm assemblies44, and that the invention can be practiced with any desirable number of arm assemblies44, for example, two, three, four, five, seven, eight, nine, ten, eleven, twelve, and the like.

The front cutting ring14can be made of steel material, such as tool steel, using an additive manufacturing (i.e., 3D printing) process. In one embodiment, the front cutting ring14is made of a unitary construction in which the sleeve member32and the plurality of arm assemblies44are integrally formed with each other. In an alternative embodiment, the front cutting ring14comprises a plurality of arm assemblies44, wherein each arm assembly44is separately attached to the sleeve member32. It should be appreciated that the invention is not limited to the number of arm assemblies44that are separately attached to the sleeve member32, and that the invention can be practiced with any desirable number of separate arm assemblies44attached to the sleeve member32, such as two, three, four, five, six, seven, eight, and the like.

Referring now toFIGS. 9 and 10, the front cutting ring14further includes a cutting head38with an insert pocket39for mounting a cutting insert40therein, and a guide pad pocket41for mounting a guide pad42therein. The cutting head38also includes a planar outer wall38aadjacent the insert pocket39, a curved, outer wall38badjacent the guide pad pocket41, a first, planar inner wall38c, a second planar inner wall38dand an arcuate central portion38ebetween the first and second inner walls38c,38d. The first, planar inner wall38cis formed at an angle, PA, with respect to the second, planar inner wall38dto enable the cutting head38to be supported by both leading arms34a,34band both trailing arms36a,36b. Specifically, both leading arms34a,34bare operably connected to first, planar inner wall38cadjacent the insert pocket39and the cutting insert40, and both trailing arms36a,36bare operably connected to the second, planar inner wall38dadjacent the guide pad pocket41and the guide pad42.

As shown inFIGS. 9 and 10, each leading arm34a,34band each trailing arm36a,36bhas a hollow interior portion extending the entire length of each arm34a,34b,36a,36bto help reduce the weight of the reamer10. The hollow interior portions of the arms34,36enable fluid to be transported from the sleeve member32to the cutting insert/workpiece interface and the guide pad/workpiece interface. Specifically, the hollow interior portion of the leading arm34adefines a fluid channel48a, the hollow interior portion of the leading arm34bdefines a fluid channel48b, the hollow interior portion of the trailing arm36adefines a fluid channel50a, and the hollow interior portion of the trailing arm36bdefines a fluid channel50b. It should be noted that all the fluid channel48a,48b,50a,50bof both the front cutting ring14and the rear cutting ring18are capable of transporting fluid therein, and that the invention can be practiced with any number of fluid channels48a,48b,50a,50btransporting fluid in both the front cutting ring14and the rear cutting head18. In one embodiment, for example, the fluid channel48ain the upper leading arm34aand the fluid channel50ain the upper trailing arm36acan be used for transporting fluid in the front cutting ring14, while the fluid channels50a,50bin only the trailing arms36a,36bcan be used for transporting fluid in the rear cutting ring18. It should be appreciated that other combinations of the fluid channels48a,48b,50a,50bused to transport fluid within the front cutting ring14and the rear cutting ring18are within the scope of the invention.

The fluid channels48a,48b,50a,50bare in fluid communication with a fluid channel32aformed in the hollow interior of the sleeve member32, as shown inFIG. 9. As shown inFIG. 10, the fluid channel50aof the trailing arm36atransports fluid from the fluid channel32aof the sleeve member32to one or more fluid openings49proximate the guide pad42. In the illustrated embodiment, the trailing arm36ahas a plurality of fluid openings49in a predetermined pattern, such as a straight line. Alternatively, the trailing arm36acan have a single, elongated opening49proximate the guide pad42. It will be appreciated that the invention is not limited by the number, size and/or shape of the fluid opening49, and that the invention can be practiced with one or more fluid openings49having any desirable size and shape, so long as sufficient fluid is provided to the guide pad/workpiece interface.

Similarly, the fluid channel50bof the trailing arm36bis used to transport fluid from the fluid channel32aof the sleeve member32to one or more fluid openings51proximate the cutting insert40. In the illustrated embodiment, only one fluid opening51is formed proximate the cutting insert40. However, it will be appreciated that the invention is not limited by the number, size and/or shape of the fluid opening51, and that the invention can be practiced with one or more fluid openings51having any desirable number, size and/or shape, so long as sufficient fluid is provided to the cutting insert/workpiece interface.

Referring now toFIGS. 11 and 12, the leading arms34and the trailing arms36have a non-circular cross-sectional shape. In the illustrated embodiment, the leading arms34and the trailing arms36are substantially kidney-shaped in cross section. Specifically, the cross-sectional area of each of the leading arms34and each of the trailing arms36is largest proximate the sleeve member32and is smallest proximate the cutting head38to help reduce the weight and the moment of inertia of the reamer10. In addition, the cross-sectional area of the fluid channels48a,48bof the leading arms34and the cross-sectional area of the fluid channels50a,50bof the trailing arms36may vary along the length of the arms34,36.

In the illustrated embodiment shown inFIGS. 9 and 10, fluid from the sleeve member32is transported only through the trailing arms36a,36bto the cutting insert/workpiece interface and the guide pad/workpiece interface. However, it will be appreciated that any one of the fluid channels48a,48b,50a,50bcan be used to transport fluid from the sleeve member32to the cutting insert/workpiece interface and the guide pad/workpiece interface. As shown inFIGS. 13 and 14, for example, the fluid channels48a,48bof one or both of the leading arms34can be used to transport fluid to the cutting insert/workpiece interface and the one or both of the trailing arms36can be used to transport fluid to the guide pad/workpiece interface.

Referring now toFIGS. 15-17, the center tube16has a double-walled construction comprising an outer wall52and an inner wall54forming a cavity56therebetween. The cavity56helps to further reduce the weight of the reamer10. The center tube16has a first, front end58and a second, rear end60. The first, front end58and the second, rear end60may have a diameter that is slightly less than the diameter of remainder of the center tube16to allow mounting of the front and rear cutting rings14,18. The center tube16may further include one or more ribs62extending between the outer wall52and the inner wall54to increase the rigidity of the center tube16. In the illustrated embodiment, the center tube16has a total of twelve ribs62that follow a helical or spiral pattern to define a helical coolant channel68through the center tube16, as shown inFIG. 17. However, it will be appreciated that the invention is not limited by the number of ribs62, and that the invention can be practiced with any desirable number of ribs62, so long as the center tube16has sufficient rigidity.

A central portion64of the center tube16may include one or more openings66disposed between the helical coolant channel68to help reduce the weight of the center tube16. In the illustrated embodiment, the openings66are polygonal in shape, similar to a parallelogram. However, it will be appreciated that the invention is not limited by the shape of the openings66, and that the invention can be practiced with openings having any desirable shape, such as circular, non-circular, and other polygonal shapes.

The cavity56and the helical coolant channel68enables the center tube16to transport pressurized fluid from the second, rear end60to the first, front end58. Specifically, the fluid is transported by the helical coolant channel68within the cavity56between the first, front end58and the second, rear end60, as shown inFIG. 17.

In the illustrated embodiment, the center tube16is made of steel and manufactured using additive manufacturing (i.e., 3D printing) to reduce the weight of the reamer10. In an alternate embodiment, the center tube16can be made of any suitable material, such as carbon fiber, carbon fiber reinforced plastic (CFRP), and the like. In this alternate embodiment, the openings66can be omitted and the entire cavity56can be used to transport fluid throughout the center tube16. In this alternate embodiment, the center tube16may be made using additive manufacturing (i.e., 3D printing) or any other suitable manufacturing process, such as sintering, plasma sputtering, and the like.

It is noted that the front cutting ring14is attached proximate the first, front end58of the center tube16and the rear cutting ring18is attached proximate the second, rear end60of the center tube16(FIGS. 1 and 2). In one embodiment, the front and rear cutting rings14,18are glued to the center tube16, and the center tube16includes grooves70at each end58,60to facilitate the gluing process. The grooves70may be helical or spiral to further facilitate the gluing of the cutting rings14,18to the center tube16. Once properly attached to the center tube16, each of the front cutting ring14and the rear cutting ring16are in fluid communication with the center tube16. Specifically, the sleeve member32of each of the front cutting ring14and the rear cutting ring16is in fluid communication with the center tube16.

The center tube16is connected to the rear machine connection member20(FIGS. 1 and 2). Once properly connected to the center tube16, the rear machine connection member20is in fluid communication with the center tube16. In turn, the rear machine connection member20can be coupled to a spindle assembly (not shown) for rotating the reamer10about the center, rotational axis, RA, and a fluid source (not shown) for providing pressurized fluid to the rear machine connection member20.

Once the rear machine connection member20is in fluid communication with the fluid source, the fluid can be provided throughout the reamer10of the invention. Specifically, fluid entering the rear machine connection member20can travel into center tube16and then through the sleeve member32of the rear cutting ring18, into the arm assemblies44and exit proximate the cutting insert40and the guide pad42of each arm assembly44. In addition, fluid can travel past the rear cutting ring18, partially through the center tube16and into the sleeve member32of the front cutting ring14, into the arm assemblies44and exit proximate the cutting insert40and the guide pad42of each arm assembly44. Further, fluid can travel through the front cutting ring14and into the front cutting body12, and exit the ports27,29(FIGS. 3 and 4) proximate each of the cutting inserts40and each of the guide pads42, respectively.

As described above, the reamer10of the invention delivers fluid in an efficient manner to the interface between the cutting tool and the workpiece without significantly altering the performance and properties, such as torsional stiffness, and the like, of the reamer10, as compared to conventional reamers.

The patents and publications referred to herein are hereby incorporated by reference.

Having described presently preferred embodiments the invention may be otherwise embodied within the scope of the appended claims.