Insert and cutting tool assembly including same

Abstract

The insert, which is configured to be assembled into a tool for cutting a workpiece, includes an upper surface including first through fourth upper corner portions formed in respective quadrants defined by a first imaginary vertical axis and a first imaginary horizontal axis that are perpendicular to each other, and a lower surface formed below the upper surface in a height direction and including first through fourth lower corner portions formed in respective quadrants defined by a second imaginary vertical axis and a second imaginary horizontal axis that are perpendicular to each other. A lower ridge portion protruding downward in the height direction is formed on the lower surface and crosses the second and fourth lower corner portions symmetrical about the center of the lower surface.

Description

[Technical field]

[0001] The present disclosure relates to an insert and a cutting tool assembly including the same. [Background technology]

[0002] Cutting tools are mainly used to cut ferrous or non-ferrous metals, and are fixed to various machine tools when in use. As a method of cutting metals using a cutting tool, for example, a method is known in which the cutting edge of the cutting tool is brought into contact with a rotating metal workpiece to perform cutting. Another method is known in which a cutting insert having a cutting edge is fixed to a tool holder, the tool holder is fixed to a machine tool, and then the cutting insert is rotated by rotating the tool holder, while the cutting insert is brought into contact with a previously fixed workpiece to cut the workpiece into a desired shape.

[0003] The cutting insert, which comes into direct contact with the workpiece, is one of the important elements in cutting. The material and shape of the cutting insert also affect the life and processing quality of the cutting tool. When cutting and removing the part of the workpiece using the cutting insert, the metal pieces generated in the form of chips must be safely discharged from the cutting area. Summary of the Invention [Problem to be solved by the invention]

[0004] Various embodiments of the present disclosure provide an insert in which a ridge portion on an upper surface and a ridge portion on a lower surface are formed to cross each other in a diagonal direction, and a cutting tool assembly including the insert. [Means for solving the problem]

[0005] An embodiment according to one aspect of the present disclosure relates to an insert configured to be assembled to a tool for cutting a workpiece. The insert according to an exemplary embodiment includes an upper surface including first to fourth upper corners formed in respective quadrants divided by a first imaginary vertical axis and a first imaginary horizontal axis perpendicular to each other, and a lower surface including first to fourth lower corners formed in respective quadrants divided by a second imaginary vertical axis and a second imaginary horizontal axis perpendicular to each other and formed below the upper surface in a height direction. The first upper corner portion and the first lower corner portion are respectively disposed on the upper side in the longitudinal direction of the tool and on the inner side in the radial direction of the tool. The first to fourth upper corner portions are sequentially disposed in a counterclockwise direction with respect to the first upper corner portion. The first to fourth lower corner portions are sequentially disposed in a counterclockwise direction with respect to the first lower corner portion. A lower ridge portion protruding downward in the height direction is formed on the lower surface and crosses the second and fourth lower corner portions symmetrical with respect to the center of the lower surface.

[0006] In one embodiment, a cutting edge is formed at each of the first through fourth upper corners.

[0007] In one embodiment, an upper ridge extending upward in a height direction is formed on the top surface and traverses first and third upper corners symmetrical about the center of the top surface.

[0008] In one embodiment, a first main cutting edge is formed at each of the first and third upper corners, and a first ramping cutting edge, which is inclined relative to the surface of the workpiece, is formed at each of the second and fourth upper corners.

[0009] In one embodiment, the upper and lower surfaces are formed above and below a longitudinal centerline perpendicular to the height direction and passing through the center of the height direction, respectively, and a first thickness between the longitudinal centerline and the first and third upper corners is greater than a second thickness between the longitudinal centerline and the second and fourth upper corners.

[0010] In one embodiment, the angle between an extension line through the upper ridge and the first imaginary horizontal axis is between 30° and 50°.

[0011] In one embodiment, a second ramping cutting edge is formed at each of the first and third lower corners, and a second main cutting edge that is inclined relative to the surface of the workpiece is formed at each of the second and fourth lower corners.

[0012] In one embodiment, the second and fourth upper corners include first and second planar portions, respectively, each of which comprises a flat surface, and the first and third lower corners include third and fourth planar portions, respectively, each of which comprises a flat surface.

[0013] In one embodiment, the lower surface includes first and second lower support surfaces formed on both sides of the lower ridge and inclined upward in the height direction, and an angle between an extension line extending from the first lower support surface and an extension line extending from the second lower support surface is between 130° and 150°.

[0014] In one embodiment, the length of the upper surface along the first imaginary horizontal axis is greater than the length of the upper surface along the first imaginary vertical axis, and the length of the lower surface along the second imaginary horizontal axis is greater than the length of the lower surface along the second imaginary vertical axis.

[0015] An embodiment according to one aspect of the present disclosure relates to a cutting tool assembly. The cutting tool assembly according to an exemplary embodiment includes an insert configured to cut a workpiece, a tool holder having an insert pocket, the insert pocket being formed at an end of the tool holder so that the insert is seated in the insert pocket, and a screw configured to fix the insert in the insert pocket. The insert includes an upper surface including first to fourth upper corner portions formed in respective quadrants divided by a first imaginary vertical axis and a first imaginary horizontal axis perpendicular to each other, and a lower surface including first to fourth lower corner portions formed in respective quadrants divided by a second imaginary vertical axis and a second imaginary horizontal axis perpendicular to each other and formed below the upper surface in a height direction. The first upper corner portion and the first lower corner portion are respectively disposed on the upper side in the longitudinal direction of the tool and on the inner side in the radial direction of the tool. The first to fourth upper corner portions are disposed in sequence in a counterclockwise direction with respect to the first upper corner portion. The first to fourth lower corner portions are disposed in sequence in a counterclockwise direction with respect to the first lower corner portion. The insert is positioned such that its lower surface faces the insert pocket, and a lower ridge is formed on the lower surface, extending downward in the height direction, across second and fourth lower corners symmetrical about the center of the lower surface.

[0016] In one embodiment, the tool holder is configured to rotate about an axis of rotation, and an insert pocket is formed in the tool holder radially outward from the axis of rotation, and when the insert is secured in the insert pocket, the third upper corner portion is positioned radially outward from the second upper corner portion.

[0017] In one embodiment, the insert pocket includes a ridge groove formed to receive the lower ridge portion. The insert pocket further includes first and second bottom surfaces formed on either side of the ridge groove and inclined upward in a height direction. The insert pocket further includes radial and axial surfaces formed above the first and second bottom surfaces in the height direction.

[0018] In one embodiment, the lower surface includes first and second lower support surfaces formed on either side of the lower ridge and angled upward in a height direction. The first lower support surface is configured to contact the first bottom surface. The second lower support surface is configured to contact the second bottom surface. A first side surface between the first and second upper corners of the insert is configured to contact the radial surface. A second side surface between the first and fourth upper corners of the insert is configured to contact the axial surface.

[0019] In one embodiment, during milling, a transfer force acting on the insert is supported by the first bottom surface and the radial surface.

[0020] In one embodiment, during ramping cutting, a transfer force acting on the insert is supported by the first bottom surface and the axial surface. Effect of the Invention

[0021] According to various embodiments of the present disclosure, the V-shaped protrusion (lower ridge) on the lower surface of the insert allows the insert to be stably fastened to the tool holder even in three-dimensional cutting such as cutting in the rotational direction, radial direction, and axial direction of a milling cutter, which enables high speed feeding and high angle cutting with the insert, thereby improving productivity in cutting the workpiece.

[0022] According to various embodiments of the present disclosure, the insert can be stably fastened to the tool holder by the ridges formed on the upper surface or the lower surface, and therefore, even when high-speed transfer or high-angle cutting is performed, the positional change of the insert within the tool holder can be minimized, and damage to the insert itself and separation of the insert from the tool holder can be prevented. [Brief description of the drawings]

[0023] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various embodiments of the present disclosure.

[0024] [Figure 1] FIG. 1 is a perspective view of a cutting tool assembly according to one embodiment of the present disclosure.

[0025] [Diagram 2] FIG. 2 is an exploded perspective view of the cutting tool assembly shown in FIG.

[0026] [Diagram 3] 3 is an exploded perspective view showing the configuration of the cutting tool assembly shown in FIG. 1, as viewed from a direction different from that of FIG. 2.

[0027] [Figure 4] 2 is a diagram showing a force that an insert receives when the cutting tool assembly shown in FIG. 1 is used for machining.

[0028] [Diagram 5] FIG. 2 is a diagram showing a state in which the cutting tool assembly shown in FIG. 1 is used for general cutting work.

[0029] [Figure 6] FIG. 2 illustrates the cutting tool assembly shown in FIG. 1 used in ramping cutting.

[0030] [Figure 7] FIG. 1 is a perspective view of an insert according to one embodiment of the present disclosure.

[0031] [Figure 8] FIG. 8 is a top view showing the upper surface of the insert shown in FIG. 7.

[0032] [Figure 9] FIG. 8 is a perspective view showing the underside of the insert shown in FIG. 7.

[0033] [Figure 10] FIG. 8 is a side view showing a side of the insert shown in FIG. 7.

[0034] [Figure 11]FIG. 8 is a diagonal side view of the insert shown in FIG. 7.

[0035] [Figure 12] FIG. 2 is an enlarged perspective view of an insert fastened to the tool holder in FIG. 1;

[0036] [Figure 13] 13 is a view for explaining a configuration in which the lower surface of the insert shown in FIG. 12 is supported within a tool holder. FIG.

[0037] [Figure 14A] FIG. 10 is a diagram for comparing the performance of a cutting tool assembly according to a comparative example with the performance of a cutting tool assembly according to an embodiment of the present disclosure.

[0038] [Figure 14B] FIG. 10 is a diagram for comparing the performance of a cutting tool assembly according to a comparative example with the performance of a cutting tool assembly according to an embodiment of the present disclosure.

[0039] [Figure 15] FIG. 13 is a perspective view of an insert according to another embodiment of the present disclosure.

[0040] [Figure 16] FIG. 16 is a perspective view showing the underside of the insert shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] The embodiments of the present disclosure are illustrated for the purpose of explaining the technical idea of ​​the present disclosure, and the scope of the rights of the present disclosure is not limited to the embodiments presented below or the specific descriptions of these embodiments.

[0042] All technical and scientific terms in this disclosure include the meaning or definition commonly understood by those of ordinary skill in the art unless otherwise defined. All terms in this disclosure are selected for the purpose of more clearly describing the disclosure, and are not selected to limit the scope of the disclosure.

[0043] As used in this disclosure, terms such as "including," "comprising," "having," and the like, should be understood as open-ended terms that may include other embodiments, unless otherwise stated in the phrase or sentence in which the term appears.

[0044] Singular terms described in this disclosure may include plural terms unless otherwise specified, and this also applies to singular terms described in the claims.

[0045] In various embodiments of the present disclosure, the terms "first", "second", etc. are used to distinguish multiple elements from one another and do not limit the order or importance of the elements.

[0046] Directional terms such as "upper", "above", etc. used herein are based on the orientation of the upper surface relative to the lower surface in the accompanying drawings. Directional terms such as "lower", "below", etc. refer to the upper direction or the opposite direction to the upper direction. The cutting inserts shown in the accompanying drawings may be oriented differently, and the directional terms should be interpreted accordingly.

[0047] Hereinafter, an embodiment of the present disclosure will be described with reference to the accompanying drawings. In the accompanying drawings, the same or corresponding components are given the same reference numerals. In the following description of the embodiments, duplicated description of the same or corresponding components will be omitted. However, even if the technology of a component is omitted, it is not intended that such a component is not included in one embodiment.

[0048] Fig. 1 is a perspective view showing a cutting tool assembly 1 according to one embodiment of the present disclosure. Fig. 2 is an exploded perspective view of the cutting tool assembly 1 shown in Fig. 1. Fig. 3 is an exploded perspective view showing the configuration of the cutting tool assembly shown in Fig. 1, seen from a direction different from the direction of Fig. 2.

[0049] The cutting tool assembly 1 can be used in a milling machine. The cutting tool assembly 1 can be configured to be provided in the milling machine and to cut a workpiece while rotating by itself. The cutting tool assembly 1 can include a tool holder 20, an insert 100, and a screw 30.

[0050] The tool holder 20 may have the shape of a solid of revolution, for example, and may be configured to rotate about a rotation axis RA. At least one insert pocket 200 may be formed at an end of the tool holder 20. The insert pocket 200 may be formed within the tool holder 20 so as to extend radially outward from the rotation axis RA. The insert 100 may be seated in the insert pocket 200 by a screw 30. The screw 30 may pass through the insert 100 and be fastened to the bottom of the insert pocket 200.

[0051] 1 to 3, three insert pockets 200 may be formed at an end of the tool holder 20, and three inserts 100 may be provided corresponding thereto. The insert pockets 200 may be arranged at an angle of 120° from each other in the circumferential direction. The inserts 100 may have a main cutting edge and a ramping cutting edge that is inclined with respect to the surface of the workpiece. When the inserts 100 are fixed in the insert pockets 200, the main cutting edge may be arranged to face radially outward from the ramping cutting edge. Details related to this will be described later.

[0052] Fig. 4 is a diagram showing the force that the insert 100 receives when the cutting tool assembly 1 shown in Fig. 1 is used for machining. Fig. 5 is a diagram showing the state in which the cutting tool assembly 1 shown in Fig. 1 is used for general cutting. Fig. 6 is a diagram showing the cutting tool assembly 1 shown in Fig. 1 used for ramping cutting. The insert 100 can cut the workpiece W while rotating around the rotation axis RA.

[0053] 6, a direction parallel to the rotation axis RA may be defined as a longitudinal direction LD of the tool holder 20. Also, a direction perpendicular to the rotation axis RA may be defined as a radial direction RD of the tool holder 20.

[0054] Referring to the coordinate system shown in FIG. 5, in a general cutting process, the cutting tool assembly 1 moves in the X-axis or Y-axis direction perpendicular to the rotation axis RA, but does not move in the Z-axis direction parallel to the rotation axis RA. Here, the X-axis direction may be the feed direction of the cutting tool assembly 1. Therefore, the workpiece W mainly comes into contact with the main cutting edge of the insert 100, and the ratio of contact with the ramping cutting edge is small. Referring to FIG. 4, the main cutting force F1 acting on the main cutting edge may be larger than the ramping cutting force F2 acting on the ramping cutting edge.

[0055] Referring to the coordinate system shown in FIG. 6, in a ramping cutting process, the cutting tool assembly 1 moves in the X-axis or Y-axis direction perpendicular to the rotation axis RA, and also moves in the Z-axis direction parallel to the rotation axis RA. For example, the ramping angle during ramping cutting can be between 1° and 2°. That is, the speed at which the cutting tool assembly 1 moves in the Z-axis direction is significantly lower than the speed at which it moves in the X-axis direction. Therefore, the workpiece W mainly comes into contact with the ramping cutting edge of the insert 100, and the ratio of contact with the main cutting edge of the workpiece W is low. Referring to FIG. 4, the main cutting force F1 acting on the main cutting edge may be greater than the ramping cutting force F2 acting on the ramping cutting edge.

[0056] Fig. 7 is a perspective view of an insert 100 according to one embodiment of the present disclosure. Fig. 8 is a top view of the upper surface of the insert 100 shown in Fig. 7. Fig. 9 is a perspective view of the lower surface of the insert 100 shown in Fig. 7. Fig. 10 is a side view of the side of the insert 100 shown in Fig. 7. Fig. 11 is a side view of the insert 100 shown in Fig. 7 from a diagonal direction.

[0057] Referring to FIG. 7, the insert 100 may be configured as a double-sided insert and may include an upper surface 101, a lower surface 102, and first to fourth side surfaces 103, 104, 108, and 109. The insert 100 may have a height centerline M1 passing through the center in the width direction and a longitudinal centerline M2 passing through the center in the height direction. The point where the height centerline M1 and the longitudinal centerline M2 intersect may be the center of mass of the insert 100. The upper surface 101 and the lower surface 102 are formed above and below the longitudinal centerline M2, respectively. The insert 100 may have an opening 150 passing through along the height centerline M1. The screw 30 shown in FIG. 2 may pass through the opening 150.

[0058] 8, the upper surface 101 may include first to fourth upper corner portions 110, 120, 130, and 140 formed in each of the quadrants divided by a first imaginary horizontal axis HA1 and a first imaginary vertical axis VA1 that are perpendicular to each other. The length of the upper surface 101 along the direction of the first imaginary horizontal axis HA1 may be longer than the length of the upper surface 101 along the direction of the first imaginary vertical axis VA1. An upper ridge portion 105 may be formed on the upper surface 101 to cross the first and third upper corner portions 110 and 130 symmetrical with respect to the center of the upper surface 101 and protrude upward in a height direction.

[0059] Referring to FIG. 8, in the insert 100, the first side 103 refers to the side formed between the first and second upper corner portions 110, 120, the second side 104 refers to the side formed between the first and fourth upper corner portions 110, 140, the third side 108 refers to the side formed between the third and fourth upper corner portions 130, 140, and the fourth side 109 refers to the side formed between the second and third upper corner portions 120, 130.

[0060] On the other hand, when the insert 100 is secured in the insert pocket 200 (see FIG. 5 ), the second and third upper corner portions 120, 130 may be located closer to the end of the tool holder 20 than the first and fourth upper corner portions 110, 140. Also, the third upper corner portion 130 may be located radially outward from the second upper corner portion 120.

[0061] 9, the lower surface 102 is formed below the upper surface 101 in the height direction. The lower surface 102 may include first to fourth lower corner portions 160, 170, 180, and 190 formed in each quadrant divided by a second imaginary vertical axis VA2 and a second imaginary horizontal axis HA2 that are perpendicular to each other. The length of the lower surface 102 along the direction of the second imaginary horizontal axis HA2 may be longer than the length of the lower surface 102 along the direction of the second imaginary vertical axis VA2. A lower ridge portion 106 may be formed on the lower surface 102, protruding downward in the height direction across the second and fourth lower corner portions 170 and 190 symmetrical with respect to the center of the lower surface 102.

[0062] The first to fourth lower corner portions 160, 170, 180, and 190 are located below the first to fourth upper corner portions 110, 120, 130, and 140, respectively, in the height direction. Therefore, the upper ridge portion 105 and the lower ridge portion 106 intersect in a diagonal direction when viewed from the top or bottom of the insert 100.

[0063] 5, the first upper corner portion 110 and the first lower corner portion 160 are respectively disposed on the upper side of the tool holder 20 in the longitudinal direction LD and on the inner side of the tool holder 20 in the radial direction RD. The first to fourth upper corner portions 110, 120, 130, and 140 are sequentially disposed in a counterclockwise direction with respect to the first upper corner portion 110. The first to fourth lower corner portions 160, 170, 180, and 190 are sequentially disposed in a counterclockwise direction with respect to the first lower corner portion 160.

[0064] On the upper surface 101, the first and third upper corners 110, 130 may have main cutting edges 111, 131, respectively, and the second and fourth upper corners 120, 140 may have ramping cutting edges 121, 141, respectively. On the lower surface 102, the second and fourth lower corners 170, 190 may have main cutting edges 171, 191, respectively, and the first and third lower corners 160, 180 may have ramping cutting edges 161, 181, respectively. In addition, the upper ridge portion 105 may be formed across the main cutting edges 111, 131, and the lower ridge portion 106 may be formed across the main cutting edges 171, 191.

[0065] The second and fourth upper corner portions 120, 140 may include first and second planar portions 122, 142, respectively, and each of the first and second planar portions may be formed of a flat surface. The first and third lower corner portions 160, 180 may include third and fourth planar portions 162, 182, respectively, and each of the third and fourth planar portions may be formed of a flat surface. Thus, the first and second planar portions 122, 142 may be located below the first and third upper corner portions 110, 130 in the height direction. Also, the third and fourth planar portions 162, 182 may be located above the second and fourth lower corner portions 170, 190 in the height direction.

[0066] 8, the angle A1 between an extension line L1 passing through the upper ridge portion 105 and the first imaginary horizontal axis HA1 may be between 30° and 50°. Similarly, the angle A2 between an extension line L2 passing through the lower ridge portion 106 and the second imaginary horizontal axis HA2 may be between 30° and 50°.

[0067] 8 and 9, the extension line L1 passing through the upper ridge portion 105 and the extension line L2 passing through the lower ridge portion 106 may be arranged in different directions (i.e., intersecting directions). The arrows in FIG. 8 indicate a situation in which a large force is applied to the main cutting edge 131 in the general milling process. If the extension lines L1 and L2 are arranged in the same direction, the circular portion C1 of the lower surface 102 has a ridge shape or a valley shape, in which case stability during the general milling process may be reduced. In contrast, according to an embodiment of the present disclosure, the extension lines L1 and L2 are arranged in intersecting directions, and the circular portion C1 of the lower surface 120 is composed of a generally flat surface, so that the insert 100 may be stably supported by the tool holder 20. Therefore, stability during the general milling process is improved.

[0068] 10, the first thickness T1 between the longitudinal centerline M2 and the first and third upper corner portions 110, 130 may be greater than the second thickness T2 between the longitudinal centerline M2 and the second and fourth upper corner portions 120, 140. Therefore, the insert 100 can perform cutting more smoothly in response to the ramping angle during ramping cutting.

[0069] 9, the lower surface 102 may include first and second lower support surfaces 151, 152 formed on both sides of the lower ridge portion 106 and inclined upward in the height direction. Referring to FIG 11, an angle B between an extension line L3 extending from the first lower support surface 151 and an extension line extending from the second lower support surface 152 may be between 130° and 150°.

[0070] Fig. 12 is an enlarged perspective view showing a state in which the insert 100 is fastened to the tool holder in Fig. 1. Fig. 13 is a view for explaining a configuration in which the lower surface 102 of the insert 100 shown in Fig. 12 is supported within the tool holder.

[0071] The insert pocket 200 may include a bottom surface 210 that contacts the insert 100. A ridge groove 215 may be formed in the bottom surface 210 to accommodate the lower ridge portion 106. The bottom surface 210 may further include first and second bottom surfaces 211, 212 formed on both sides of the ridge groove 215 and inclined upward in the height direction. In addition, the insert pocket 200 may further include a radial surface 213 and an axial surface 214 formed above the first and second bottom surfaces 211, 212 in the height direction.

[0072] The first lower support surface 151 of the insert 100 may be configured to contact a first bottom surface 211 of the insert pocket 200. The second lower support surface 152 of the insert 100 may be configured to contact a second bottom surface 212 of the insert pocket 200. The first side surface 103 of the insert 100 may be configured to contact a radial surface 213 of the insert pocket 200 and the second side surface 104 of the insert 100 may be configured to contact an axial surface 214 of the insert pocket 200 when the insert 100 is secured in the insert pocket 200 by the screw 30.

[0073] Cutting resistance refers to the resistance that the insert experiences as the cut is advanced. Cutting resistance can act as three mutually perpendicular components: main force, transport force, and thrust force. The main force is the largest, the thrust force is smaller than the main force, and the transport force is smaller than the thrust force. The main force can be referred to as the force component parallel to the cutting direction, the transport force can be referred to as the force component acting in a direction opposite to the transport direction of the cutting tool assembly, and the thrust force can be referred to as the force component opposite to the cutting depth.

[0074] If the lower surface of the insert is composed of only a flat surface, the force acting in the radial direction of the milling cutter is supported by the radial contact surface of the tool holder, and the insert can be firmly fastened to the tool holder during machining. However, there is no separate support surface for the force acting in the opposite radial direction of the milling cutter in situations such as ramping cutting. Since the insert is supported only by the screw, problems such as deformation and damage of the screw, and insertion loss may occur. According to the embodiment of the present disclosure, the lower surface 102 of the insert 100 is not composed of only this flat surface. Therefore, the above problems can be solved.

[0075] When the insert 100 is used in a general milling process, a main force acting on the insert 100 may be supported by the first bottom surface 211 and the second bottom surface 212. A transfer force, which is a force acting on the insert 100 in the radial direction of the cutting tool, may be primarily supported by the second bottom surface 212 and additionally supported by the radial surface 213. Meanwhile, a thrust force acting on the insert 100 may be supported by the second bottom surface 212 and the axial surface 214.

[0076] When the insert 100 is used in a ramping cutting process, a main force acting on the insert 100 may be supported by the first bottom surface 211 and the second bottom surface 212, as in the case of a general milling process. Unlike the general milling process, a transfer force, which is a force acting on the insert 100 in the radial direction of the cutting tool, may be supported by the first bottom surface 211 and the axial surface 214. On the other hand, a thrust force acting on the insert 100 may be supported by the second bottom surface 212 and the axial surface 214.

[0077] 14A and 14B are diagrams for comparing the performance of a cutting tool assembly according to a comparative example with the performance of the cutting tool assembly 1 according to an embodiment of the present disclosure.

[0078] Figure 14A shows the screw stress (σ) and total displacement of a cutting tool assembly according to a comparative example, and Figure 14B shows the screw stress (σ) and total displacement of a cutting tool assembly 1 according to an embodiment of the present disclosure. The screw stress (σ) indicates the load acting on the screw, and the total displacement indicates the extent to which the insert has moved from its initial position.

[0079] It can be seen that the screw stress of the cutting tool assembly 1 according to the embodiment of the present disclosure is reduced by approximately 30% compared to the screw stress of the cutting tool assembly according to the comparative example. Therefore, the load acting on the screw is dramatically reduced. Therefore, even if high-intensity processing is performed for a long time, damage to the screw can be prevented.

[0080] It can be seen that the total deformation amount of the cutting tool assembly 1 according to the embodiment of the present disclosure is reduced by approximately 40% compared to the total deformation amount of the cutting tool assembly according to the comparative example. Therefore, the total deformation amount during machining can be dramatically reduced. Therefore, even if high-intensity machining is performed for a long time, cutting precision can be maintained.

[0081] Fig. 15 is a perspective view showing an insert 300 according to another embodiment of the present disclosure. Fig. 16 is a perspective view showing the bottom surface of the insert 300 shown in Fig. 15. The duplicated description of the contents described in the previous embodiment will be omitted.

[0082] The insert 300 may be a single-sided insert. The insert 300 may have an opening 350 penetrating from the upper surface 301 to the lower surface 302. Therefore, a cutting edge may be formed only on the upper surface 301 of the insert 300, and no cutting edge may be formed on the lower surface 302. Meanwhile, a cutting edge may be formed on each of the first to fourth upper corner portions 310, 320, 330, and 340 of the upper surface 301.

[0083] The lower surface 302 may function to be seated in the insert pocket 200 of the tool holder 20. The lower surface 302 may include first to fourth lower corner portions 360, 370, 380, and 390. A lower ridge portion 306 may be formed to cross the second lower corner portion 360 and the fourth lower corner portion 390. The lower surface 302 may include first and second lower support surfaces 351 and 352 formed on both sides of the lower ridge portion 306 and inclined upward in the height direction.

[0084] Although some embodiments have been described, these embodiments are presented merely as examples and are not intended to limit the scope of the present disclosure. In fact, the embodiments described herein may be embodied in various other forms. Furthermore, various omissions, substitutions, and modifications may be made in the form of the embodiments described herein without departing from the spirit of the present disclosure. The appended claims and their equivalents are intended to cover such forms or modifications within the spirit of the present disclosure.

Claims

1. An insert configured to be seated in an insert pocket of a tool holder and to cut a workpiece, an upper surface including first to fourth upper corner portions formed in respective quadrants defined by a first imaginary vertical axis and a first imaginary horizontal axis perpendicular to each other; a lower surface including first to fourth lower corner portions formed in each quadrant defined by a second imaginary vertical axis and a second imaginary horizontal axis perpendicular to each other, the lower surface being formed below the upper surface in a height direction; The first to fourth upper corner portions are sequentially arranged in a counterclockwise direction relative to the first upper corner portion when the insert is viewed from above, The first to fourth lower corner portions are sequentially arranged in a counterclockwise direction relative to the first lower corner portion when the insert is viewed from above, The first to fourth lower corner portions are located in order below the first to fourth upper corner portions in the height direction, the second and fourth lower corners are symmetrical with respect to a center of the lower surface; the first lower corner portion and the third lower corner portion are located higher in the height direction than the second lower corner portion and the fourth lower corner portion, The lower surface is configured to seat in the insert pocket; the lower surface includes a lower ridge portion protruding downward in the height direction and extending diagonally between the second and fourth lower corner portions, a first lower support surface formed on one side of the lower ridge portion, and a second lower support surface formed on the other side of the lower ridge portion, When the insert is viewed from a side, the first and second lower support surfaces on the lower surface are inclined upward in the height direction from the lower ridge portion toward the end portion, the first lower support surface extends from the lower ridge portion toward the first lower corner portion, and the second lower support surface extends from the lower ridge portion toward the third lower corner portion. insert.

2. a cutting edge is formed at each of the first through fourth upper corners; The insert according to claim 1.

3. an upper ridge portion is formed on the upper surface, the upper ridge portion extending diagonally between the first and third upper corner portions symmetrical with respect to a center of the upper surface; The insert according to claim 1.

4. a first main cutting edge is formed at each of the first and third upper corners, and a first ramping cutting edge is formed at each of the second and fourth upper corners; The insert according to claim 3.

5. The upper surface and the lower surface are formed above and below a longitudinal center line that is perpendicular to the height direction and passes through a center in the height direction, a first thickness between the longitudinal centerline and the first and third upper corners is greater than a second thickness between the longitudinal centerline and the second and fourth upper corners; The insert according to claim 4.

6. an angle between an extension line passing through the upper ridge portion and the first imaginary horizontal axis is between 30° and 50°; The insert according to claim 3.

7. a second ramping cutting edge is formed at each of the first and third lower corners, and a second main cutting edge is formed at each of the second and fourth lower corners. The insert according to claim 4.

8. the second and fourth upper corner portions include first and second planar portions, respectively, each of the first and second planar portions being a flat surface; the first and third lower corner portions include third and fourth planar portions, respectively, each of the third and fourth planar portions being formed with a flat surface; The insert according to claim 7.

9. An angle between an extension line extending from the first lower support surface and an extension line extending from the second lower support surface is between 130° and 150°. The insert according to claim 1.

10. a length of the upper surface along the first imaginary horizontal axis is longer than a length of the upper surface along the first imaginary vertical axis; a length of the lower surface along the second imaginary horizontal axis is longer than a length of the lower surface along the second imaginary vertical axis; The insert according to claim 1.

11. In a cutting tool assembly, an insert configured to cut a workpiece; a tool holder having an insert pocket, the insert pocket being formed at an end of the tool holder such that the insert rests in the insert pocket; a screw configured to secure the insert in the insert pocket; The insert comprises: an upper surface including first to fourth upper corner portions formed in respective quadrants defined by a first imaginary vertical axis and a first imaginary horizontal axis perpendicular to each other; The second imaginary vertical axis and the second imaginary horizontal axis are perpendicular to each other. a lower surface formed below the upper surface in a height direction, the lower surface including first to fourth lower corner portions formed in the lower corner portions, The first to fourth upper corner portions are sequentially arranged in a counterclockwise direction relative to the first upper corner portion when the insert is viewed from above, The first to fourth lower corner portions are sequentially arranged in a counterclockwise direction relative to the first lower corner portion when the insert is viewed from above, The insert is arranged such that the lower surface faces the insert pocket; The first to fourth lower corner portions are located in order below the first to fourth upper corner portions in the height direction, the second and fourth lower corners are symmetrical with respect to a center of the lower surface; the first lower corner portion and the third lower corner portion are located higher in the height direction than the second lower corner portion and the fourth lower corner portion, the lower surface includes a lower ridge portion protruding downward in the height direction and extending diagonally between the second and fourth lower corner portions, a first lower support surface formed on one side of the lower ridge portion, and a second lower support surface formed on the other side of the lower ridge portion, When the insert is viewed from a side, the first and second lower support surfaces on the lower surface are inclined upward in the height direction from the lower ridge portion toward the end portion, the first lower support surface extends from the lower ridge portion toward the first lower corner portion, and the second lower support surface extends from the lower ridge portion toward the third lower corner portion. Cutting tool assembly.

12. the tool holder is configured to rotate about an axis of rotation; the insert pocket is formed in the tool holder radially outward from the axis of rotation; When the insert is fixed in the insert pocket, the third upper corner portion is disposed radially outward from the second upper corner portion. The cutting tool assembly of claim 11.

13. the insert pocket includes a ridge groove formed to receive the lower ridge portion; The insert pocket further includes first and second bottom surfaces formed on both sides of the ridge groove and inclined upward in the height direction, The insert pocket further includes a radial surface and an axial surface formed above the first and second bottom surfaces in the height direction. The cutting tool assembly of claim 11.

14. The first lower support surface is configured to contact the first bottom surface, the second lower support surface is configured to contact the second bottom surface; a first side of the insert between the first and second upper corners configured to contact the radial surface; a second side of the insert between the first and fourth upper corners configured to contact the axial surface; The cutting tool assembly of claim 13.

15. During milling, a transfer force acting on the insert is supported by the second bottom surface and the radial surface. The cutting tool assembly of claim 13.

16. During ramping cutting, a transfer force acting on the insert is supported by the first bottom surface and the axial surface. The cutting tool assembly of claim 13.

17. A cutting insert having eight corner portions, an upper surface including first to fourth upper corner portions, the first to fourth upper corner portions being sequentially arranged in a counterclockwise direction with respect to the first upper corner portion when the cutting insert is viewed from above; a lower surface including first to fourth lower corner portions formed below the upper surface in a height direction of the cutting insert and each of the first to fourth lower corner portions being below a corresponding one of the first to fourth upper corner portions in the height direction; a main cutting edge formed at the first and third upper corner portions; ramping cutting edges formed at the second and fourth upper corners; First to fourth side surfaces connecting the upper surface and the lower surface; an opening extending between the upper surface and the lower surface and having a height centerline that is a center of 180° rotational symmetry of the cutting insert; the lower surface is configured to seat in an insert pocket of a tool holder; the second lower corner portion and the fourth lower corner portion are rotationally symmetrical by 180° with respect to the center line in the height direction, the first lower corner portion and the third lower corner portion are rotationally symmetrical by 180° with respect to a center line in the height direction and are located higher in the height direction than the second lower corner portion and the fourth lower corner portion, The lower surface is a lower ridge portion protruding downward in the height direction and extending diagonally between the second and fourth lower corner portions; a first lower support surface formed on one side of the lower ridge portion; a second lower support surface formed on the other side of the lower ridge portion; When the cutting insert is viewed from a side, the first and second lower support surfaces on the lower surface are inclined upward in the height direction from the lower ridge portion toward an end portion, the first and second lower support surfaces form an obtuse angle along the lower ridge; the first lower support surface extends from the lower ridge toward the first lower corner, and the second lower support surface extends from the lower ridge toward the third lower corner. Cutting insert.

18. The cutting insert as described in claim 17, wherein the obtuse angle is between 130° and 150°.

19. The cutting insert is double-sided, The cutting insert comprises: a main cutting edge formed at the second and fourth lower corner portions; ramping cutting edges formed at the first and third lower corners; an upper ridge portion protruding upward in the height direction and extending diagonally between the first and third upper corner portions; first and second upper support surfaces formed on opposite sides of the upper ridge portion, inclined downward from the upper ridge portion in the height direction to form an obtuse angle along the upper ridge portion, The cutting insert according to claim 18.

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