RU2833180C2 - Cutting insert and cutting tool on which this cutting insert is installed - Google Patents

Abstract

FIELD: processing of materials by cutting.

SUBSTANCE: group of inventions relates to processing of materials by cutting and can be used for processing of workpieces at right angle. Cutting insert comprises four rectangular upper surfaces passing between two opposite side surfaces, and cutting edge portions, which comprise a second major cutting edge formed on the long sides of the upper surfaces, and a first major cutting edge connected to the second major cutting edge at an angle. Side surfaces comprise a second major cutting edge rear surface extending from the side smooth surface and connected to the second major cutting edge, and a rear surface of the first major cutting edge extending from the side smooth surface and connected to the first major cutting edge. Angle formed by extension lines of first main cutting edge and side smooth surface is greater than or equal to angle formed by extension lines of boundary line of rear surface of first major cutting edge and side smooth surface. Cutting tool comprises cutting inserts of said design installed in its sockets, arranged at positive axial front angle.

EFFECT: ensuring stable multistage processing of the workpiece at a right angle.

6 cl, 13 dwg

Description

Field of technology

The invention relates to a cutting insert and a cutting tool on which said cutting insert is mounted.

Prior art

In general, a cutting insert is installed in a cutting tool fixed in a metal-cutting machine and is used for cutting a workpiece, such as a machine part, etc., made of ferrous metal, non-ferrous metal, non-metallic material, etc.

The cutting insert has a top surface, a bottom surface facing in the opposite direction, side surfaces connecting the top surface and the bottom surface, and cutting edges forming boundaries between the top surface and the side surfaces and cutting blanks.

However, Fig. 11 to 13 show a cutting insert 10 described in Korean Patent Publication No. 2014-0004149. For reference, Fig. 11, 12, and 13 correspond to Fig. 1, 2, and 4 of the above-mentioned Korean patent, respectively, and for convenience of description, in the absence of modifications, reference numerals used in the above-mentioned Korean patent are used, and the reference numerals do not necessarily refer to the same components even if they are the same as reference numerals used in the following description of the invention.

The cutting insert 10 in question has a subsidiary cutting edge 26, a corner cutting edge 28 and a main cutting edge 22, and the main cutting edge 22 has a first section 22a of the main cutting edge and a second section 22b of the main cutting edge. In addition, the corner cutting edge 28 is rounded with a predetermined radius of curvature, and in connection with the corner cutting edge 28 there is an angular rear surface 40. In addition, the angular rear surface 40 is rounded and passes between the main rear surface 42 and the subsidiary rear surface 38.

However, taking into account the above-described design, the cutting insert 10 of the prior art has a second section 22b of the main cutting edge located at a negative (-) axial rake angle, and the cutting insert 10 is tilted forward (to the left in Fig. 12) to provide an inclination angle (α in Fig. 12) relative to the lower surface of the workpiece, and, accordingly, mechanical processing of the workpiece up to the second section 22b of the main cutting edge behind the first section 22a of the main cutting edge located at a positive axial rake angle, leads to obtaining a workpiece of an undesirable shape.

In addition, in the right-angle machining, the end of the corner back surface 40 associated with the corner cutting edge 28 participating in the machining is used in multiple steps, and since it projects beyond the first section 22a of the main cutting edge (in the left direction as shown in Fig. 12), there is a problem of requiring re-machining of the workpiece or causing interference with the workpiece.

Disclosure of invention

Technical problem

In order to solve the above and other problems, an object of the invention is to provide a cutting insert for right-angle machining, in which the cutting insert has eight angles and can still perform stable multi-stage right-angle machining without re-machining the workpiece.

Technical solution

In order to solve the above-mentioned problems, a cutting insert according to an embodiment of the invention is a cutting insert for right-angle machining, which may have two opposite side surfaces, four rectangular upper surfaces extending between the two side surfaces, a mounting hole extending through the two side surfaces, and cutting edge portions formed at locations where the side surfaces and the upper surfaces are connected to each other, wherein the cutting insert may be axially symmetrical by 180° with respect to an imaginary axial line that passes through the center of the mounting hole, and axially symmetrical by 180° with respect to an imaginary axial line that passes through the center of the upper surfaces, the cutting edge portions may include a second main cutting edge formed on the long sides of the upper surfaces, a first main cutting edge connected to the second main cutting edge at an angle, an angular cutting edge connected to the first main cutting edge, and an auxiliary cutting edge formed on the short sides of the upper surfaces, and connected to the corner cutting edge, a lateral smooth surface surrounding the fastening hole, a rear surface of the second main cutting edge, extending from the lateral smooth surface and connected to the second main cutting edge, and a rear surface of the first main cutting edge, extending from the lateral smooth surface and connected to the first main cutting edge and connected to the rear surface of the second main cutting edge at an angle, and, when viewed from the side of the upper surfaces, the angle formed by the extension line of the first main cutting edge and the extension line of the lateral smooth surface is greater than or equal to the angle formed by the extension line of the boundary line of the rear surface of the first main cutting edge and the extension line of the lateral smooth surface.

In addition, the first main cutting edge may be a straight line, and the back surface of the first main cutting edge may comprise a single plane.

In addition, when viewed from the side surfaces, the extension line of the rear surface of the auxiliary cutting edge may be located on the right side of the extension line that connects two opposite auxiliary cutting edges based on an imaginary center line passing through the center of the upper surfaces, and said extension lines may form an acute angle.

In addition, the upper surfaces may comprise an upper smooth surface comprising a single plane, a front surface of the second main cutting edge extending from the second main cutting edge towards the upper smooth surface, a front surface of the first main cutting edge extending from the first main cutting edge towards the upper smooth surface, a front surface of the corner cutting edge extending from the corner cutting edge towards the upper smooth surface, a front surface of the auxiliary cutting edge extending from the auxiliary cutting edge towards the upper smooth surface, and a rear surface of the auxiliary cutting edge adjacent to the front surface of the auxiliary cutting edge and starting from the front surface of the auxiliary cutting edge.

In addition, the upper smooth surface may be formed below the lowest point of the second main cutting edge.

The cutting tool on which the above-described cutting insert is installed is characterized in that the cutting insert is installed on the cutting tool at a positive axial front angle.

Effects of invention

The cutting insert according to the above-described design according to the embodiment of the invention is made with a two-stage main cutting edge, i.e. with a first main cutting edge and a second main cutting edge, and is also made with the first main cutting edge in the form of a straight line and the rear surface of the first main cutting edge formed on a single plane, so that the rear surface of the first main cutting edge is offset in the direction of the axis of rotation of the cutting tool, thereby eliminating contact with the rectangular inner wall of the workpiece at the top right (at the very top) of the cutting insert during mechanical cutting and ensuring efficient execution of multi-stage mechanical processing at a right angle.

At the same time, it is clear, although not expressly stated, that the invention includes other effects that can be obtained on the basis of the above-described design.

Brief description of the drawings

Fig. 1 shows a cutting insert according to an embodiment of the invention, in perspective view;

in Fig. 2 - the cutting insert in Fig. 1, a perspective view when viewed from above;

in Fig. 3 - the cutting insert in Fig. 1, side view;

in Fig. 4 - the cutting insert in Fig. 1, top view;

in Fig. 5 - the arrangement of the first main cutting edge and the rear surface of the first main cutting edge relative to the smooth side surface in Fig. 4;

Fig. 6A is a rear surface of the auxiliary cutting edge formed as a positive surface in the cutting insert of Fig. 1, and Fig. 6B is part B of Fig. 6A, a view on an enlarged scale;

Fig. 7A shows a cutting insert of the prior art engaging the vertical inner wall of the workpiece, and Fig. 7B shows a cutting insert not engaging the vertical inner wall of the workpiece;

in Fig. 8 - the relative position of the upper smooth surface and the second main cutting edge in the cutting insert in Fig. 1;

Fig. 9A shows the cutting insert of Fig. 1 installed in the cutting tool, and Fig. 9B shows a perspective view from another direction;

Fig. 10A shows the configuration of the cutting tool socket in Fig. 9A and 9B, and Fig. 10B shows the socket, an enlarged view;

Fig. 11-13 shows a cutting insert of the prior art.

The best mode of carrying out the invention

The following is a detailed description of preferred embodiments of the invention with reference to the drawings, as will be obvious to those skilled in the art. However, the invention may be implemented in a variety of other ways and should not be construed as being limited to the specific examples given in the description.

As shown in Fig. 1-4, the cutting insert 100 according to the embodiment of the invention is a so-called tangential type cutting insert 100, which can be used for right-angle machining and has two opposite side surfaces 1, four upper surfaces 2 of approximately rectangular shape, passing between the two side surfaces 1, a fastening hole 3 passing through the two side surfaces 1, and cutting edge portions 4 formed at the places where the side surfaces 1 and the upper surfaces 2 are connected to each other.

In addition, the cutting insert 100 is axially symmetrical by 180° with respect to an imaginary axial line C1 that passes through the center of the fastening hole 3, and is axially symmetrical by 180° with respect to an imaginary axial line C2 that passes through the center of the upper surface 2.

At the same time, the cutting edge portions 4 have a first main cutting edge 41, a second main cutting edge 42, an angular cutting edge 43 and an auxiliary cutting edge 44.

The second main cutting edge 42 is formed on the long side of the upper surface 2, as shown in Fig. 4.

The first main cutting edge 41 is connected to the second main cutting edge 42 at an angle, and the first main cutting edge 41 has a linear shape.

The corner cutting edge 43 is connected to the first main cutting edge 41 in a curved shape.

An auxiliary cutting edge 44 is formed on the short side of the upper surface 2 and is connected to the corner cutting edge 43.

As shown in Fig. 3, the side surface 1 has a side flat surface 13, a rear surface 12 of the second main cutting edge and a rear surface 11 of the first main cutting edge.

The lateral flat surface 13 has a single plane and surrounds the fastening hole 3, into which the fastening bolt is inserted after being attached to the cutting tool.

The rear surface 12 of the second main cutting edge extends from the side flat surface 13 and is connected to the second main cutting edge 42.

The rear surface 11 of the first main cutting edge extends from the side flat surface 13 and is connected to the first main cutting edge 41, being in contact with the rear surface 12 of the second main cutting edge. In particular, the rear surface 11 of the first main cutting edge has a single plane.

As shown in Fig. 4, the upper surfaces 2 have an upper flat surface 21, a front surface 22 of the second main cutting edge, a front surface 23 of the first main cutting edge, a front surface 24 of the corner cutting edge, a front surface 25 of the minor cutting edge and a rear surface 26 of the minor cutting edge, which form a single plane. For reference, the front surface corresponds to the surface along which the chips removed from the workpiece during its mechanical processing flow.

The front surface 22 of the second main cutting edge extends from the second main cutting edge 42 towards the upper smooth surface 21.

The front surface 23 of the first main cutting edge extends from the first main cutting edge 41 towards the upper smooth surface 21.

The front surface 24 of the corner cutting edge extends from the corner cutting edge 43 towards the upper smooth surface 21.

The front surface 25 of the auxiliary cutting edge extends from the auxiliary cutting edge 44 towards the upper smooth surface 21.

The rear surface 26 of the auxiliary cutting edge adjoins the front surface 25 of the auxiliary cutting edge and starts from the front surface 25 of the auxiliary cutting edge. In other words, in Fig. 4, the rear surface 26 of the auxiliary cutting edge projects relatively further than the front surface 25 of the auxiliary cutting edge in a direction outside the plane of the page.

As shown in Fig. 5, when looking at the cutting insert 100 from the side of the upper surface 2, the angle α formed by the extension line L1 of the first main cutting edge 41 and the extension line L2 of the side smooth surface 13 is preferably greater than or equal to the angle β formed by the extension line L3 of the boundary line of the rear surface 11 of the first main cutting edge and the extension line L2 of the side smooth surface 13. If β>α, a problem arises in that the rigidity of the rear surface 11 of the first main cutting edge is reduced.

Based on this, as shown in Fig. 7B, the cutting insert 100 can be formed with a two-stage main cutting edge, that is, with a first main cutting edge 41 and a second main cutting edge 42, and can also be formed with the first main cutting edge 41 in the form of a straight line and the back surface 11 of the first main cutting edge formed on a single plane, so that the boundary line of the back surface 11 of the first main cutting edge is offset in the direction of the rotation axis R of the cutting tool 300, thereby eliminating contact with the rectangular inner wall of the workpiece 200 in the region of the upper right side A of the cutting insert during cutting machining and ensuring efficient execution of multi-stage machining at a right angle. On the other hand, as shown in Fig. 7A, the cutting insert of the prior art does not have a configuration corresponding to the first main cutting edge 41 of the cutting insert 100, but only has a back surface with a rounded corner, and in this case there is contact with the rectangular inner wall of the workpiece 200, making it impossible to perform a complete multi-stage machining at a right angle, which does not include re-machining.

However, as shown in Fig. 6, when looking at the cutting insert 100 from the side surface 1, the extension line L4 of the rear surface 26 of the minor cutting edge is located on the right side (based on Fig. 6B) from the extension line L5 which connects the two opposite minor cutting edges 44-1 and 44-2 based on the center of the upper surfaces 2, and the rear surface 26 of the minor cutting edge forms a so-called positive surface. In other words, the extension line L5 and the extension line L4 form an acute angle γ.

In addition, as shown in Fig. 8, the upper smooth surface (the so-called projection surface) 21 of the cutting insert 100 is formed below the lowest place 421 by the second head of the cutting edge 42. In addition, as described above, the upper smooth surface 21 is a single plane. Therefore, the cutting insert 100 has proper characteristics for manufacturing and a large fastening surface (upper flat surface) for fastening to the cutting tool, ensuring proper stability during multi-step machining at a right angle.

Next, with reference to Fig. 9 and 10, a brief description is given of a cutting tool 300 equipped with a cutting insert 100 having the above-described structure according to an embodiment of the invention.

The cutting tool 300 has a plurality of sockets 301 into which the cutting inserts 100 are mounted.

The nest 301 has an upper seat 302, on which two upper surfaces 2 of the cutting insert 100 rest, respectively, and one side seat 303, on which the side surface 1 of the cutting insert 100 rests. The upper seats 302 and the side seat 302 are formed on a single plane.

As shown in Fig. 9B, the cutting insert 100 is mounted on the cutting tool 300 at a positive axial rake angle.

Although the invention has been described with reference to several examples presented herein, the invention should not be limited to these examples only, and a number of other changes and modifications made by those skilled in the art, based on the basic idea of the invention, also fall within the scope of the claims.

Industrial applicability

The invention can be used in a cutting tool for mechanical processing of a workpiece.

Claims (9)

1. A cutting insert for right angle machining, comprising two opposite side surfaces, four rectangular top surfaces extending between the two side surfaces, a mounting hole extending through the two side surfaces, and cutting edge portions formed at locations where the side surfaces and the top surfaces are connected to each other, wherein the cutting insert is axially symmetrical by 180° with respect to an imaginary center line that passes through the center of the mounting hole, and axially symmetrical by 180° with respect to an imaginary center line that passes through the center of the top surfaces, wherein the cutting edge portions comprise a second main cutting edge formed on the long sides of the upper surfaces, a first main cutting edge connected to the second main cutting edge at an angle, an angular cutting edge connected to the first main cutting edge, and an auxiliary cutting edge formed on the short sides of the upper surfaces and connected to the angular cutting edge, the side surfaces comprise a side smooth surface surrounding the fastening hole, a rear surface of the second main cutting edge extending from the side smooth surface and connected to the second main cutting edge, and a rear surface of the first main cutting edge extending from the side smooth surface and connected to the first main cutting edge and connected to the rear surface of the second main cutting edge at an angle, and, when viewed from the side of the upper surfaces, the angle formed by the extension line of the first main cutting edge and the extension line of the lateral smooth surface is greater than or equal to the angle formed by the extension line of the boundary line of the rear surface of the first main cutting edge and the extension line of the lateral smooth surface. 2. The cutting insert according to claim 1, wherein the first main cutting edge is a straight line, and the rear surface of the first main cutting edge is formed on a single plane. 3. The cutting insert according to claim 1, wherein the upper surfaces comprise an upper smooth surface including a single plane, a front surface of the second main cutting edge extending from the second main cutting edge toward the upper smooth surface, a front surface of the first main cutting edge extending from the first main cutting edge toward the upper smooth surface, a front surface of the corner cutting edge extending from the corner cutting edge toward the upper smooth surface, a front surface of the secondary cutting edge extending from the secondary cutting edge toward the upper smooth surface, and a rear surface of the secondary cutting edge adjacent to the front surface of the secondary cutting edge and starting from the front surface of the secondary cutting edge. 4. A cutting insert according to claim 3, wherein, when viewed from the side surfaces, the extension line of the rear surface of the auxiliary cutting edge is located on the right side of the extension line that connects two opposite auxiliary cutting edges based on an imaginary center line passing through the center of the upper surfaces, and said extension lines form an acute angle. 5. The cutting insert according to claim 3, wherein the upper smooth surface is formed below the lowest point of the second main cutting edge. 6. A cutting tool on which a cutting insert according to item 1 is installed, wherein the cutting insert is installed on the cutting tool at a positive axial rake angle.