GB2574437A

GB2574437A - Cutting tool

Info

Publication number: GB2574437A
Application number: GB1809268.4A
Authority: GB
Inventors: Chen Yujie; Patrick Vogler Michael; Thierry Andre Marchione
Original assignee: Caterpillar Inc
Current assignee: Caterpillar Inc
Priority date: 2018-06-06
Filing date: 2018-06-06
Publication date: 2019-12-11
Also published as: GB201809268D0

Abstract

The cutting tool 100 is for performing a cutting operation and a burnishing operation on a workpiece (102, Figure 2). The tool includes a tool body 106 having an outer peripheral surface 118 and extending along a central longitudinal axis 116. Cutting elements 108 circularly arranged along the outer peripheral surface are configured to perform the cutting operation on the work piece. One or more burnishing elements 134a, 134b, 134c are arranged along the outer peripheral surface. Each burnishing element 134 is disposed between two consecutive cutting elements and is configured to perform the burnishing operation. Each burnishing element is configured to move radially inwardly and outwardly to enable at least one of the cutting operation and the burnishing operation. The burnishing element/s and the cutting elements lie in a common plane 136 that extends orthogonal to the central longitudinal axis.

Description

CUTTING TOOL

Technical Field [0001] The present disclosure generally relates to a cutting tool. More particularly, the disclosure relates to a cutting tool for performing at least one of a cutting operation or a burnishing operation on a workpiece.

Background [0002] Cutting tools are used to perform chip removal operations on workpieces of different materials, such as metals and composite materials, in a wide range of applications. Typically, during a chip removal operation, tensile stresses are generated on a machined surface of a workpiece. These tensile stresses may lead to the formation of deformities, such as micro-cracks, on the machined surface. Formation of such deformities on the machined surface may deteriorate several characteristics of the workpiece, as and when the workpiece may be subjected to cyclical loads during use, for example. These characteristics may include fatigue life and corrosion resistance. To improve these characteristics, a burnishing operation is performed on the machined surface of the workpiece. Burnishing operations include bringing one or more burnishing elements into relatively close contact with the machined surface with sufficient force, so as to smoothen the machined surface, and thus eliminate any deformities present on the machined surface.

[0003] Typically, chip removal operations and burnishing operations are performed under separate stages of a machining operation, in separate time intervals, and by use of separate tools. The use of separate tools may increase an overall cost of machining the workpiece, while applying separate time intervals to the machining process may increase an overall time required to machine the workpiece.

[0004] Japanese Patent No. 3,750,974B2 (hereinafter referred to as ’974 reference) relates to a tool combining a cutting blade and burnishing roller to

-2perform dimensional correction and roller burnishing surface finishing in one simultaneous process. The ’974 reference discloses a parallel arrangement of a cutter and a roller to enable the simultaneous processing.

Summary of the Invention [0005] In one aspect, the disclosure is directed towards a cutting tool. The cutting tool includes a tool body that has an outer peripheral surface, and that extends along a central longitudinal axis. Further, the cutting tool includes a plurality of cutting elements and one or more burnishing elements. The cutting elements are circularly arranged along the outer peripheral surface and are configured to perform a cutting operation on the workpiece. The burnishing elements are arranged along the outer peripheral surface. Each burnishing element is disposed between two consecutive cutting elements and is configured to perform the burnishing operation. Each burnishing element is configured to move radially inwardly and outwardly to enable at least one of the cutting operation and the burnishing operation. Also, the burnishing elements and the cutting elements lie in a common plane that extends orthogonal to the central longitudinal axis.

Brief Description of the Drawings [0006] FIG. 1 is a perspective view of a cutting tool, in accordance with an embodiment of the present disclosure;

[0007] FIG. 2 is a sectional view of the cutting tool, indicating a state of the cutting tool in which the cutting tool may perform a cutting operation, in accordance with an embodiment of the present disclosure;

[0008] FIG. 3 is a sectional view of the cutting tool, indicating a state of the cutting tool in which the cutting tool may simultaneously perform the cutting operation and a burnishing operation, in accordance with an embodiment of the present disclosure; and

-3[0009] FIG. 4 is a sectional view of the cutting tool, indicating a state of the cutting tool in which the cutting tool may perform the burnishing operation, in accordance with an embodiment of the present disclosure.

Detailed Description [0010] Referring to FIGS. 1, 2, 3, and 4, a cutting tool 100 is shown. The cutting tool 100 is configured to perform at least one of a cutting operation or a burnishing operation on a workpiece 102 (see FIG. 2). A cutting operation, according to one aspect of the present disclosure, may refer to a chip removal operation on the workpiece 102. In an exemplary embodiment, the cutting tool 100 is a rotary cutter 104 which may be used in a milling machine or a machining center to perform a milling operation. The cutting tool 100 includes a tool body 106, a plurality of cutting elements 108, and one or more burnishing assemblies 110.

[0011] The tool body 106 may include an annular cutter head portion 112 and a shaft portion 114. The shaft portion 114 may be coupled with a machine spindle (not shown), so as to receive torque from the machine spindle during operation, and execute a rotational motion about a central longitudinal axis 116 to facilitate at least one of the cutting operation or the burnishing operation. As shown in FIG. 1, the shaft portion 114 may extend linearly away from the annular cutter head portion 112 such that the shaft portion 114 and the annular cutter head portion 112 may in unison define a common, central longitudinal axis 116 of the tool body 106. As an example, the tool body 106 may be rotated about the central longitudinal axis 116, and the annular cutter head portion 112 (including cutting elements 108) may be operably engaged with the workpiece 102 to perform the cutting operation (and/or the burnishing operation) on the workpiece 102. The annular cutter head portion 112 is ring-shaped, and accordingly defines an outer peripheral surface 118 and a concentrically disposed, inner peripheral surface 120, around the central longitudinal axis 116.

-4[0012] Further, the annular cutter head portion 112 may include a plurality of slots 122. For example, three slots are shown, namely, a first slot 122a, a second slot 122b, and a third slot 122c. Each slot 122 may extend radially outwardly from the inner peripheral surface 120 to the outer peripheral surface 118. As an example, the first slot 122a is defined by an interior surface 124 of the annular cutter head portion 112. The interior surface 124 of the first slot 122a may include a threaded portion 126, an unthreaded portion 128, and an intermediate portion 130 disposed in between the threaded portion 126 and the unthreaded portion 128. The threaded portion 126 may be disposed between the inner peripheral surface 120 and the intermediate portion 130. The unthreaded portion 128 may be disposed between the intermediate portion 130 and the outer peripheral surface 118. Features discussed for the first slot 122a may be contemplated for the second slot 122b and for the third slot 122c, as well.

[0013] With continued reference to FIGS. 1, 2, 3, and 4, the cutting elements 108 will now be discussed. As an example, the cutting elements 108 are three in number, namely a first cutting element 108a, a second cutting element 108b, and a third cutting element 108c, and are circularly arranged along the outer peripheral surface 118 of the tool body 106. For example, the first cutting element 108a is arranged in a circumferentially spaced relation to the second cutting element 108b, along the outer peripheral surface 118. A similar arrangement may be contemplated between the second cutting element 108b and the third cutting element 108c, and between the third cutting element 108c and the first cutting element 108a. The cutting elements 108 may be disposed alternatively in relation to the slots 122. For example, the first cutting element 108a may be disposed between the first slot 122a and the second slot 122b, the second cutting element 108b may be disposed between the second slot 122b and the third slot 122c, and the third cutting element 108c may be disposed between the third slot 122c and the first slot 122a. Although the cutting tool 100 is shown to include three cutting elements 108a, 108b, and 108c, a higher or lower number of cutting elements 108 may be circularly arranged along the outer peripheral surface 118 of the tool body

-5106. Further, although not limited, the plurality of cutting elements 108, may be detachably mounted to the annular cutter head portion 112 of the tool body 106. As an example, the cutting elements 108 may be mounted to the outer peripheral surface 118 by using one or more fastening members (not shown) like screws, bolts, rivets, and pins. Moreover, each of the cutting elements 108 may extend outwardly of the outer peripheral surface 118 to define a cutting edge 132 that may be brought into engagement with the workpiece 102 for machining the workpiece 102.

[0014] The burnishing assemblies 110 will now be discussed. The burnishing assemblies 110 are, for example, three in number, and include a first burnishing assembly 110a, a second burnishing assembly 110b, and a third burnishing assembly 110c. The burnishing assemblies 110a, 110b, 110c are respectively and at least partially disposed within slots 122a, 122b, and 122c. Although the cutting tool 100 is shown to include three burnishing assemblies 110a, 110b, and 110c, a higher or lower number of burnishing assemblies 110 may be circularly arranged along the outer peripheral surface 118 of the tool body 106. The burnishing assemblies 110 include corresponding burnishing elements 134 (for example, a first burnishing element 134a, a second burnishing element 134b, and a third burnishing element 134c) that may contact and interact with the workpiece 102 during operations, so as to improve characteristics, including fatigue life and corrosion resistivity, of the workpiece 102. The burnishing elements 134 may be disposed radially outermost of the remainder of their corresponding burnishing assemblies 110, so as to be arranged along the outer peripheral surface 118 of the tool body 106. As shown, the burnishing elements 134 and cutting elements 108 lie in a common plane 136. In one example, the common plane 136 may extend in a direction orthogonal to the central longitudinal axis 116 of the tool body 106.

[0015] In an embodiment, with the burnishing assemblies 110 being positioned within the corresponding slots 122, the burnishing elements 134 may be deployed alternatively in relation to the cutting elements 108, such that each burnishing element 134 may be disposed between two consecutive cutting elements 108, along

-6the outer peripheral surface 118 of the tool body 106. For example, the first burnishing element 134a may be disposed between the first cutting element 108a and the third cutting element 108c, the second burnishing element 134b may be disposed between the first cutting element 108a and the second cutting element 108b, and the third burnishing element 134c may be disposed between the second cutting element 108b and the third cutting element 108c. The alternative disposition of the burnishing elements 134, vis-a-vis the cutting elements 108, and a layout of the burnishing elements 134 and the cutting elements 108 in the common plane 136, allows the cutting tool 100 to perform the cutting operation and the burnishing operation simultaneously.

[0016] For simplicity and ease in understanding, the forthcoming description will include discussions pertaining to the first burnishing assembly 110a alone. Such discussions will be applicable to the second burnishing assembly 110b and the third burnishing assembly 110c. Wherever required, however, references to the second burnishing element 134b and the third burnishing element 134c (or the burnishing elements 134, in general) may also be used. The first burnishing assembly 110a may include the first burnishing element 134a (as already noted above), an adjusting means 138, a support structure 140, a spring 142, and a damper unit 144.

[0017] The first burnishing element 134a may be configured to contact the workpiece 102 so as to improve workpiece characteristics, as noted above. For example, the first burnishing element 134a may be configured to smoothen a surface, such as a machined surface 102a, of the workpiece 102. The first burnishing element 134a may include a spherical shaped, or a ball shaped profile that may be configured to contact the workpiece 102 at a point. Nonetheless, it is possible for the first burnishing element 134a to include a differently shaped profile. For example, the first burnishing element 134a may include a cylindrical profile that may define a line of contact upon contact with the workpiece 102, or an oblong shaped profile that may define a corresponding arcuate contact with the workpiece 102, and, thus, machine the workpiece 102 to the required specification.

-7In some embodiments, the first burnishing element 134a may be formed of a rigid material like hardened steel. Other materials may be contemplated.

[0018] The support structure 140 may include a receptacle 146 having a profile complimentary to the profile of the first burnishing element 134a. For example, the receptacle 146 may be spherically shaped, as with the spherical shape of the first burnishing element 134a. Moreover, the receptacle 146 may include dimensions similar to dimensions of an outer profile of the first burnishing element 134a. In so doing, the receptacle 146 may accommodate, support, and retain the first burnishing element 134a therein, and may allow the first burnishing element 134a to be freely manipulated along multiple degrees of freedom to execute a rotary motion about a center 148 defined by a curvature of the spherically shaped receptacle 146. However, it may be noted that a portion 150 (see configuration in FIG. 2) of the first burnishing element 134a may be exposed to the outside of the receptacle 146, and that the first burnishing element 134a may be only partially enclosed in the support structure 140, as shown. In so doing, an outermost extent 152 of the first burnishing assembly 110a may be defined, and which may contact the workpiece 102, and may roll against the machined surface 102a of the workpiece 102 to perform the burnishing operation on the workpiece 102. As shown, the support structure 140 may include a first seat 154 to support a portion of the spring 142 and the damper unit 144 (discussed further below). In an example, the support structure 140 may be formed from one or more of stainless steel, tungsten, and brass.

[0019] The adjusting means 138 may facilitate the first burnishing element 134a to move radially inwardly and outwardly relative to the outer peripheral surface 118 through the first slot 122a. The adjusting means 138 may include an adjustable screw 156 or a stud shaped component that include threads formed on its outer surface, and which are engageable with the threaded portion 126 of the interior surface 124 of the first slot 122a. Therefore, a rotation of the adjusting means 138 may result in a linear movement of the adjusting means 138 through the first slot 122a. In some embodiments, a rotation of the adjusting means 138

-8concomitantly causes a rotation of the remainder of the first burnishing assembly 110a along an axis 158 of the first slot 122a. In some embodiments, the adjusting means 138 includes a hexagonal hole 160 into which an Allen key or a Hex key (not shown) may be inserted and rotated with a pre-defined torque to move the adjusting means 138 within the first slot 122a. Further, the adjusting means 138 includes a second seat 162 to support another portion of the spring 142.

[0020] The damper unit 144 may include an assembly of a cylinder 164 and a rod 166. The rod 166 may be linearly extendable relative to the cylinder 164, while the cylinder 164 may store a compressible fluid 168 that may bias the rod 166 in the extended position (see configuration in FIG. 2). As an example, the rod 166 may be coupled (such as threadably coupled) to the first seat 154, while the cylinder 164 may be coupled (such as threadably coupled) to the second seat 162. In that manner, the damper unit 144 may be disposed between the support structure 140 and the adjusting means 138, as shown.

[0021] The spring 142 may be coupled to the first seat 154 and the second seat 162 (as noted above), and may be exemplarily disposed around the damper unit 144, as shown. The spring 142 may be configured to absorb shock during the burnishing operation, while the damper unit 144 may restrict the support structure 140 (or the burnishing elements 134) from undue vibrations or oscillations during the burnishing operation.

[0022] In some embodiments, each of the burnishing assemblies 110 may be freely movable within the respective slots 122 (i.e., the burnishing assemblies 110 may be disposed within the respective slots 122 without any threaded engagement with the interior surface 124 of slot 122, and a wedge structure (not shown) may be used to control the radial movement of the burnishing elements 134 within the slots 122. For example, the wedge structure may be in slidable contact with the second seat 162 of each of the burnishing assemblies 110, and upon an axial movement (i.e., along the central longitudinal axis 116 of the wedge structure, the wedge structure may slip against each of the second seats 162, thereby facilitating

-9the radial inward and/or outward movement of each of the burnishing assemblies 110 synchronously.

Industrial Applicability [0023] During operations, the adjusting means 138 may be rotated to facilitate a radial movement of the burnishing elements 134 either inwardly or outwardly, enabling the cutting tool 100 to perform at least one of the cutting operation or the burnishing operation. For example, when solely a cutting operation is needed, the burnishing elements 134 are moved inwardly by rotation of the adjusting means 138 (see arrow, A, in FIG. 2). As a result, the cutting edges 132 of the cutting elements 108 take the radially outermost position of the cutting tool 100 (see configuration in FIG. 2). In such a configuration, the cutting edges 132 of the cutting tool 100 may be able to contact the workpiece 102 to solely perform a cutting operation on the workpiece 102, along a pre-defined path 170.

[0024] Conversely, when both the burnishing operation and cutting operation is needed, the burnishing elements 134 are moved outwardly by reversing rotation (see arrow, B, in FIG. 2) of the adjusting means 138. As a result, the burnishing elements 134 may attain a state where the burnishing elements 134 and the cutting edges 132 are at the same outermost extent (see configuration in FIG. 3). In such a configuration, both the burnishing elements 134 and the cutting elements 108 may respectively perform a burnishing operation and a cutting operation simultaneously, along the pre-defined path 170. In one example, a burnishing element may execute a burnishing action on a portion of the workpiece 102 in succession to a cutting action performed by the cutting edge 132 on the same portion of the workpiece 102. During the burnishing operation, the burnishing elements 134 may roll against the portion of the workpiece 102, exerting sufficient force against the machined surface 102a of the workpiece 102 to obtain a smooth machined surface.

[0025] Further, when solely a burnishing operation is needed, the adjusting means 138 may be further rotated in the reversed direction (see arrow, B). As a

-10result, the burnishing elements 134 are moved further radially outwardly beyond the cutting edges 132 of the cutting elements 108 to be at the radially outermost extent (see configuration in FIG. 4). In such a configuration, the burnishing elements 134 may be able to contact the surface of the workpiece 102 to solely perform a burnishing operation along another pre-defined path 172.

[0026] In some embodiments, one or more of the burnishing elements 134 may be replaced by a cutting element 108. For example, the burnishing elements 134a, 134b may be removed, and in place of the burnishing elements 134a, 134b, a cutting element (such as the first cutting element 108a) may be provided. As a result of such a configuration, the cutting tool 100 may include a total of five cutting elements 108 and one burnishing element 134. In such a case, it may be noted that the support structures 140 associated with the burnishing elements 134a, 134b may need to include an altered configuration (e.g., with inserts) so as to accommodate the cutting elements (such as the first cutting element 108a). Also, as a result, the burnishing assemblies 110a, 110b (that would have been otherwise associated with burnishing elements 134a, 134b) may be identified as cutting assemblies instead.

[0027] In continuation with the above embodiment, if the third burnishing element 134c were arranged at the radially outermost extent (similar to the configuration in FIG. 4) and the remaining burnishing assemblies 110a, 110b were to respectively include cutting assemblies with cutting elements (such as the first cutting element 108a), a cutting operation and burnishing operation may be performed simultaneously. In such a case, during operation, as the cutting tool 100 may rotate and move along the workpiece 102, a cutting element 108 adjacent to and following the third burnishing element 134c along the cutting action may refrain from performing the cutting operation. However, during the infeeding process, as the cutting tool 100 may rotate and move further along the workpiece 102, the remaining cutting elements 108 may contact the workpiece 102 and may perform the cutting operation on the workpiece 102. In this way, the cutting tool 100 may be able to perform a cutting operation and a burnishing operation

-11simultaneously. Also, by applying such a configuration (i.e., by increasing the number of cutting elements 108) to the cutting tool 100, an operation of the cutting tool 100 may be made more efficient and less time consuming.

[0028] The present disclosure discloses a cutting tool that may be convertible between a sole cutting tool - to a simultaneously operable cutting and burnishing tool - to a sole burnishing tool. Such a conversion helps save time and effort in an actual machining environment. Further, a simultaneous functioning of the cutting elements 108 and the burnishing elements 134, as disclosed above, reduces a time taken to machine a workpiece. Accordingly, a cost to machine a workpiece becomes commensurately less.

[0029] It will be apparent to those skilled in the art that various modifications and variations can be made to the system of the present disclosure without departing from the scope of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice of the system disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalent.

Claims

Claims

What is claimed is:

1. A cutting tool (100) comprising:

a tool body (106) including an outer peripheral surface (118) and extending along a central longitudinal axis (116);

a plurality of cutting elements (108) circularly arranged along the outer peripheral surface (118) and configured to perform a cutting operation on a workpiece (102); and one or more burnishing elements (134) arranged along the outer peripheral surface (118), wherein each burnishing element (134a, 134b, 134c) of the one or more burnishing elements (134) is disposed between two consecutive cutting elements (108), and is configured to perform a burnishing operation on the workpiece (102), each burnishing element (134a, 134b, 134c) is configured to move radially inwardly and outwardly to enable at least one of the cutting operation and the burnishing operation, wherein the one or more burnishing elements (134) and the plurality of cutting elements (108) lie in a common plane (136) extending orthogonal to the central longitudinal axis (116).