Cutting insert and cutting tool on which such insert is installed

Abstract

FIELD: mechanical engineering.SUBSTANCE: group of inventions relates to the cutting processing of parts made of iron, non-ferrous metals and non-metallic materials and can be used in cutting tools equipped with cutting inserts. The cutting insert comprises a top surface, a bottom surface, a side surface, a mounting hole passing through the top surface and the bottom surface, and a cutting edge at which the top surface and the side surface are connected to each other. The cutting edge has a main cutting edge, a first corner cutting edge extending from one side of the main cutting edge, and a second corner cutting edge extending from the other side of the main cutting edge. When viewed from the side surface, the main cutting edge has an asymmetrical, upwardly curved shape relative to an imaginary centre line passing through the mounting hole. When viewed from the top surface, the main cutting edge has a straight shape. The design features of a cutting insert and a cutting tool comprising such an insert are disclosed.EFFECT: increased rigidity of the cutting insert and service life of the tool.5 cl, 7 dwg

Description

[0001] Technical field

[0002] The invention relates to a cutting insert and a cutting tool equipped with such an insert, more specifically, to a cutting insert that provides an increase in service life, and to a cutting tool equipped with such a cutting insert.

[0003] Prior Art

[0004] Generally, the cutting insert is fixed to the cutting tool mounted on the machine tool and is used for cutting workpieces such as mechanical parts made of iron, non-ferrous metals or non-metallic materials.

[0005] Such a cutting insert comprises a top surface, a bottom surface located opposite it, a side surface connecting the top and bottom surfaces, and a cutting edge forming a boundary between the top surface and the side surface, wherein the cutting edge essentially cuts the workpiece.

[0006] At the same time, the cutting edge lead angle of a high-feed milling head is typically less than 15°. Although a small lead angle results in a smaller cutting depth per pass, it also produces small chips, making it suitable for machining parts of various shapes. In particular, it is often used for machining mold parts, which are inherently high-hardness and complex in shape. Therefore, this small lead angle should be suitable for various types of multi-purpose machining (such as ramping and helical gear cutting), and chip removal efficiency is extremely important when machining complex parts.

[0007] However, for conventional square-shaped cutting inserts used for high-feed machining, the clearance angle of the corner section is made large to accommodate the machining of such complex-shaped parts. In this case, although machining various complex-shaped parts is possible, corner chipping of the cutting insert often occurs when machining high-hardness molding materials.

[0008] In addition, in a conventional square-shaped cutting insert for high-feed machining, the helical direction of the cutting edge is set in the "+" direction. This slightly improves cutting performance, but chips from the high-hardness molding material flow into the unused corner of the cutting insert, which can cause damage.

[0009] [Prior Art Document] Korean Patent Application Laid-Open No. 10-2016-0019952 (Publication date: February 22, 2016).

[0010] Disclosure of invention

[0011] Technical problem

[0012] The invention is aimed at solving the above-described technical problems, and the object of the invention is to create a cutting insert and a cutting tool equipped with such a cutting insert that provides both a sufficient clearance angle and rigidity of the cutting insert, and also increases the service life by protecting the unused angle of the insert.

[0013] Technical solution

[0014] In order to achieve the above object, a cutting insert according to one of the possible embodiments of the invention comprises a top surface, a bottom surface, a side surface, a mounting hole passing through the top surface and the bottom surface, and a cutting edge on which the top surface and the side surface are connected to each other, wherein the cutting edge includes a main cutting edge, a first corner cutting edge extending from one side of the main cutting edge, and a second corner cutting edge extending from the other side of the main cutting edge, wherein, when viewed from the side surface, the main cutting edge has an asymmetric upwardly curved shape relative to an imaginary center line passing through the mounting hole, and when viewed from the top surface, the main cutting edge has a straight shape, and a first contact point at which the main cutting edge and the first corner cutting edge meet,located higher from the bottom surface than the second contact point at which the other main cutting edge adjacent to said main cutting edge and the first corner cutting edge meet.

[0015] Furthermore, when viewed from the top surface, the cutting insert is rotationally symmetrical at an angle of 90° × n (where n is a natural integer) relative to an imaginary center line, the first corner cutting edge is symmetrical relative to an imaginary diagonal center line passing through the center of the mounting hole, and the second corner cutting edge is symmetrical relative to another imaginary diagonal center line also passing through the center of the mounting hole.

[0016] In addition, the first corner portion of the lower surface corresponding to the first corner cutting edge is asymmetrical with respect to the imaginary diagonal center line, and the second corner portion of the lower surface corresponding to the second corner cutting edge is asymmetrical with respect to the imaginary diagonal center line.

[0017] In addition, the corner relief surface extending from the first corner cutting edge has a relief angle that increases in the direction from the first contact point to the second contact point.

[0018] In addition, the shortest distance from the third contact point, at which the first corner portion is connected to the edge portion of the lower surface, to the first contact point is less than the shortest distance from the fourth contact point, at which the first corner portion is connected to another edge portion of the lower surface adjacent to the above-mentioned edge, to the second contact point.

[0019] In addition, a plurality of concave recesses are provided on the upper surface along the cutting edge, the length of which gradually increases in the direction from the first contact point to the second contact point.

[0020] Benefits of the invention

[0021] The cutting insert of the above-described configuration according to a possible embodiment of the invention provides the following positive effects.

[0022] Since the cutting insert according to the invention has a main cutting edge that has an asymmetrical upward curved shape (when viewed from the side) and a substantially straight shape (when viewed from above), the chips separated from the workpiece do not roll off from the first corner cutting edge to the second corner cutting edge, but curl in place, which makes it possible to protect the opposite corner of the insert (the corner where the second corner cutting edge is located).

[0023] Furthermore, when the cutting insert according to the invention is used for machining inclined surfaces at a high feed rate, the clearance angle on the inner side (the side of the first corner cutting edge) of the cutting insert can be properly fixed, while strengthening the rigidity of the main cutting edge.

[0024] Furthermore, although not directly stated, the invention also provides certain other beneficial effects that can be expected when using the above-described configuration.

[0025] Brief description of drawings

[0026] Fig. 1 shows a cutting insert according to a possible embodiment of the invention, in perspective view;

[0027] in Fig. 2 – cutting insert in Fig. 1, side view;

[0028] in Fig. 3 – cutting insert in Fig. 1, top view;

[0029] in Fig. 4 – cutting insert in Fig. 1, bottom view;

[0030] in Fig. 5 – the cutting insert in Fig. 1, a perspective view from the lower surface;

[0031] in Fig. 6 - a cutting tool in which a cutting insert shown in Fig. 1 is installed;

[0032] Fig. 7 is an exploded view of an assembly comprising a cutting tool, a cutting insert shown in Fig. 1, and a fastening bolt.

[0033] Variants of the invention

[0034] The following is a detailed description of possible embodiments of the invention, with reference to the drawings, to enable those of ordinary skill in the art to which the invention pertains to practice. However, the invention may be embodied in various embodiments and is not limited to the embodiments described in this application. It should be noted that the terms "first," "second," and the like do not indicate order, but are used to distinguish components that have the same name.

[0035] As shown in Fig. 1, a cutting insert according to a possible embodiment of the invention comprises an upper surface (1), a lower surface (3), side surfaces (2), a mounting hole (4) passing through the upper surface (1) and the lower surface (3), and a cutting edge (5) located at the location where the upper surface (1) and the side surface (2) are connected to each other. The cutting insert according to the invention, when viewed from the upper surface (1), has a substantially square shape, wherein the lower surface (3) functions as a support surface, and the upper surface (1) functions as an inclined surface, thus forming a single-sided cutting insert.

[0036] The cutting edge (5) includes a main cutting edge (51), a first corner cutting edge (52) extending from one side of the main cutting edge (51), and a second corner cutting edge (53) extending from the other side of the main cutting edge (51).

[0037] As shown in Fig. 2, which shows a cutting insert according to the invention, when viewed from the side surface (2), the main cutting edge (51) has an asymmetrical upward curved shape relative to an imaginary center line (C1) passing through the fastening hole (4).

[0038] Furthermore, as shown in Fig. 3, which shows the cutting insert according to the invention, when viewed from the side of the upper surface (1), the main cutting edge (51) has a substantially straight shape.

[0039] Thus, due to the fact that the main cutting edge (51) has an asymmetrical upward curved shape (when viewed from the side) and a substantially straight shape (when viewed from above), the chips separated from the workpiece during processing do not come off from the first corner cutting edge (52) to the second corner cutting edge (53), but curl in place, which makes it possible to protect the opposite corner of the insert (the corner where the second corner cutting edge is located).

[0040] Furthermore, as can be seen from Fig. 2, the first contact point (61), at which the main cutting edge (51) and the first corner cutting edge (52) meet, is located higher from the bottom surface (3) than the second contact point (62), at which the other main cutting edge (54), adjacent to the main cutting edge (51), and the first corner cutting edge (52) meet.

[0041] As can be seen from Fig. 3, which shows the cutting insert according to the invention, when viewed from the top surface (1), this cutting insert is rotationally symmetrical at an angle of 90° × n (where n is a natural integer) relative to the imaginary center line (C1). Thus, when viewed from the top surface, it can be seen that the cutting insert according to the invention can have four identical main cutting edges and four identical corner cutting edges.

[0042] In addition, the first corner cutting edge (52) is symmetrical with respect to an imaginary diagonal center line (C2) passing through the center of the mounting hole (4), and the second corner cutting edge (53) is symmetrical with respect to another imaginary diagonal center line (C3) also passing through the center of the mounting hole (4).

[0043] As can be seen from Fig. 4, the first corner portion (31) of the lower surface corresponding to the first corner cutting edge (52) is asymmetrical with respect to the imaginary diagonal center line (C2). It should be noted that the term "corresponding" used here means that, as shown in Fig. 3 and 4, when looking in the direction from the upper surface (1) to the lower surface (3) (or in the direction from the lower surface to the upper surface) in the direction perpendicular to the said surfaces, it can be seen that the aforementioned portions overlap each other.

[0044] In addition, the second corner portion (32) of the lower surface (3), corresponding to the second corner cutting edge (53), is asymmetrical with respect to the imaginary diagonal center line (C2).

[0045] As shown in Fig. 3, the corner relief surface (21) extending from the first corner cutting edge (52) has a relief angle that increases in the direction from the first contact point (61) to the second contact point (62) (β > α).

[0046] As can be seen from Fig. 5, the shortest distance (L1) from the third contact point (63) (in which the first corner portion (31) is connected to the edge portion (32) of the lower surface (3)) to the first contact point (61) is less than the shortest distance (L2) from the fourth contact point (64) (in which the first corner portion (31) is connected to the other edge portion (33) of the lower surface (3) adjacent to the edge portion (32)) to the second contact point (61).

[0047] Thanks to the above configuration, when the cutting insert according to the invention is used for machining inclined planes at a high feed rate, the clearance angle on the inner side (the side of the first corner cutting edge) of the cutting insert can be properly fixed, while strengthening the rigidity of the main cutting edge.

[0048] Furthermore, as shown in Fig. 3, a plurality of concave recesses (11) are formed on the upper surface (1) along the cutting edge, the length of which gradually increases in the direction from the first contact point (61) to the second contact point (62). This configuration ensures the possibility of heat dissipation when processing high-hardness molding materials, and the gradual increase in the length of said recesses enables maximum heat dissipation as the cutting depth increases.

[0049] Next, with reference to Fig. 6 and 7, a brief description is given of a cutting tool (300) equipped with cutting inserts (100) of the above-described configuration according to a possible embodiment of the invention.

[0050] The cutting tool (300) comprises a plurality of socket parts (301) designed to receive cutting inserts (100) therein.

[0051] The socket part (301) comprises a lower seat part (302), on which the lower surface (3) of the cutting insert (100) is located, and two side seat parts (303), on which the side surfaces (2) of the cutting insert (100) are seated. The side seat parts (303) are made in the form of flat surfaces with grooves.

[0052] As stated above, the angular R shape is symmetrical on the upper surface and asymmetrical on the lower surface, so that when machining inclined surfaces, sufficient clearance angle can be ensured on the inside of the cutting insert where clearance angle is required, and can be ensured on parts requiring strength, such as parts where the main cutting edge starts.

[0053] In addition, the asymmetrical upward curved shape of the spiral main cutting edge keeps the chips in place while machining the workpiece, thereby protecting the unused corner and prolonging the service life of the cutting insert.

[0054] Although the preferred embodiments of the invention have been described in detail above, the scope of the invention is not limited thereto, and various improvements and modifications that can be made by those skilled in the art using the basic idea of ​​the invention are also included within the scope of the invention.

[0055] Industrial applicability

[0056] The cutting insert according to the invention can be used in the field of cutting tools.

Claims

1. A cutting insert comprising a top surface, a bottom surface, a side surface, a mounting hole passing through the top surface and the bottom surface, and a cutting edge at which the top surface and the side surface are connected to each other, wherein the cutting edge includes a main cutting edge, a first corner cutting edge extending from one side of the main cutting edge, and a second corner cutting edge extending from the other side of the main cutting edge; when viewed from the side surface, the main cutting edge has an asymmetrical, upwardly curved shape relative to an imaginary center line passing through the mounting hole; when viewed from the top surface, the main cutting edge has a straight shape, and a first contact point at which the main cutting edge and the first corner cutting edge meet is located higher from the bottom surface than a second contact point at which another main cutting edge adjacent to said main cutting edge and the first corner cutting edge meet, wherein when viewed from the upper surface, the cutting insert is rotationally symmetrical at an angle of 90° × n, where n is a natural integer, relative to an imaginary center line, and the first corner cutting edge is symmetrical about an imaginary diagonal center line passing through the center of the mounting hole, and the second corner cutting edge is symmetrical about another imaginary diagonal center line, also passing through the center of the mounting hole, wherein the first corner portion of the lower surface corresponding to the first corner cutting edge is asymmetrical with respect to the imaginary diagonal center line, and the second corner portion of the lower surface, corresponding to the second corner cutting edge, is asymmetrical with respect to the imaginary diagonal center line.

2. The cutting insert of claim 1, wherein the corner relief surface extending from the first corner cutting edge has a relief angle that increases in the direction from the first contact point to the second contact point.

3. A cutting insert comprising a top surface, a bottom surface, a side surface, a mounting hole passing through the top surface and the bottom surface, and a cutting edge at which the top surface and the side surface are connected to each other, wherein the cutting edge includes a main cutting edge, a first corner cutting edge extending from one side of the main cutting edge, and a second corner cutting edge extending from the other side of the main cutting edge; when viewed from the side surface, the main cutting edge has an asymmetrical, upwardly curved shape relative to an imaginary center line passing through the mounting hole; when viewed from the top surface, the main cutting edge has a straight shape, and a first contact point at which the main cutting edge and the first corner cutting edge meet is located higher from the bottom surface than a second contact point at which another main cutting edge adjacent to said main cutting edge and the first corner cutting edge meet, wherein when viewed from the upper surface, the cutting insert is rotationally symmetrical at an angle of 90° × n, where n is a natural integer, relative to an imaginary center line, and the first corner cutting edge is symmetrical about an imaginary diagonal center line passing through the center of the mounting hole, and the second corner cutting edge is symmetrical about another imaginary diagonal center line, also passing through the center of the mounting hole, wherein the shortest distance from the third point of contact, in which the first corner portion is connected to the edge portion of the lower surface, to the first point of contact is less than the shortest distance from the fourth point of contact, in which the first corner portion is connected to another edge portion of the lower surface adjacent to the said edge portion, to the second point of contact.

4. A cutting insert according to claim 1, in which a plurality of concave recesses are formed on the upper surface, located along the cutting edge, the length of which gradually increases in the direction from the first contact point to the second contact point.

5. A cutting tool in which a cutting insert according to item 1 or 3 is installed.

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