RU2566242C1 - High-speed cutting tool and insert - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: claimed insert comprises top working surface and opposite bottom location surface. Peripheral side surface comprises major and minor side surfaces arranged at acute angle to said bottom location surface. Locking through bores are made in top and bottom location surfaces and provided with recesses at bottom parts exposed to the bottom location surface. This insert has at least two cutting edges including conjugated sections of the major and minor cutting edges directed at acute internal angles to the bottom location surface to make angular cutting edges. Top location surface comprises leading surfaces abutting on every cutting edge and extending therefrom and inward the top working surface. Wear-resistant coating is applied on the insert bottom location surface its factor of rest or sliding friction together with the material of support surfaces of high-speed cutting tool seats being larger than the sliding friction factor of face surfaces.

EFFECT: higher mechanical strength of the insert, reliable attachment.

6 cl, 6 dwg

Description

Technical field

The present invention relates to devices used in the processing of materials by cutting, in particular to a high-speed cutting tool for processing aluminum and its alloys.

State of the art

Rotary cutting tools are known having a working part with sockets in which replaceable cutting inserts are installed, in particular having wear-resistant coatings of working surfaces with a low coefficient of sliding friction, and are mechanically fixed with screws. When using such a cutting tool for processing at high speeds, in particular, products made of aluminum and its alloys, problems arise in stability and reliable fastening of replaceable cutting inserts due to the action of a large amount of alternating loads caused by cutting forces and centrifugal forces. As a result of the action of centrifugal forces, clamping screws are subjected to a significant load, since interchangeable cutting inserts, as a rule, are held in addition to clamping screws due to friction forces arising on the base surfaces of interchangeable cutting inserts in contact with the base surfaces of the cutting tool seats. Thus, it is necessary to increase the reliability of fixing removable cutting inserts, including by reducing the load on the clamping screws, which are the most loaded structural element of the cutting tool.

To solve the tasks, there are known designs having mating gear base surfaces of nests and interchangeable cutting inserts, for example, disclosed in US Pat. Nos. 5,057,732. Such a connection requires additional costs for its accurate manufacture, which can lead to uncertain positioning of the interchangeable cutting insert in the socket of the cutting tool body and create additional stresses in the replaceable cutting insert.

US Pat. No. 6,196,769 discloses a design for a cutting tool for high speed machining in which the base surfaces of the housing socket are convex in a V shape and contact with a concave V shape in the interchangeable cutting insert. In this design, the mechanical strength of the interchangeable cutting insert is significantly reduced, and, as in the previous technical solution, additional difficulties arise in its accurate basing.

The RF patent 2469821 discloses a design of a cutting tool for high-speed machining, in which the base surfaces of the housing socket have a concave V-shape and are in contact with a convex V-shaped surface of a replaceable cutting insert. In this design, the mechanical strength of the cutting tool body is significantly reduced and additional difficulties arise in the exact basing of the interchangeable cutting insert.

RF patent 2375156 discloses a design of a high-speed end mill and a cutting insert for a high-speed end mill, in which the cutting plate comprises an upper surface having a flat central portion, a flat lower surface and a plurality of side surfaces. Moreover, the front surface forms an angle of five to twenty-five degrees relative to the central portion of the upper surface of the cutting insert, and all cutting edges are located in the same plane.

This design also does not allow for stable and reliable fastening of the replaceable cutting insert, since it has a low coefficient of rest or sliding friction on the base surfaces in contact with the base surfaces of the cutting tool seats.

The present invention is aimed at creating an improved design of a high-speed cutting insert for its use in processing, in particular, aluminum and its alloys with high cutting speeds by increasing its mechanical strength and reliability of fastening.

The present invention also aims to provide a high speed cutting tool for securing and using the proposed high speed cutting insert. The specified technical result is achieved through a combination of features described in the relevant claims. In particular, a high-speed cutting insert is proposed, the lower base surface of which has a wear-resistant coating with a high coefficient of rest or sliding friction paired with the material of the supporting surfaces of the nests of the proposed cutting tool, greater than the sliding friction coefficient of the front surfaces of the insert. A high speed cutting tool for securing and using the proposed high speed cutting insert is also provided.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a high speed cutting insert comprising:

the upper working and opposite the lower base surface, the peripheral side surface located between them, including the main side and auxiliary side surfaces located at an acute internal angle to the lower base surface,

at least one or more fixing through holes extending between the upper working and lower base surfaces, with samples made in the lower parts of the fixing through holes and open to the lower base surface,

at least two cutting edges, each cutting edge comprising successively mating portions of the main and auxiliary cutting edges directed at sharp internal angles to the lower base surface to form corner cutting edges on the top of the cutting edges,

the upper working surface includes front surfaces adjacent respectively to each cutting edge and extending from the cutting edges mainly inward towards the upper working surface.

In accordance with the present invention, a wear-resistant coating is applied to the lower base surface with a high coefficient of rest or sliding friction paired with the material of the supporting surfaces of the nests of the high-speed cutting tool, larger than the sliding friction coefficient of the front surfaces,

According to one preferred embodiment, the lower base surface is in particular coated with a wear-resistant coating of titanium aluminum nitride (Ti Al Ν), or aluminum titanium nitride (Al Ti Ν), or titanium (Ti).

According to another preferred embodiment, the corner cutting edges are made with a radial rounding, or rectilinear, or in the form of parts of second-order surfaces, in particular a cylinder, or an ellipsoid of revolution, or a cone, or a hyperboloid of revolution, or a paraboloid of revolution.

In accordance with another preferred embodiment, grinding chamfers are made on the auxiliary side surfaces.

In accordance with another preferred embodiment, the bevels are made at acute internal angles to the lower base surface of the bevels, the angle being uneven along the portion of the main cutting edge.

The present invention also provides a high speed cutting tool, in particular an end mill, having:

a housing with a working surface located around the axis of rotation in which the sockets are made, each socket having a supporting surface with one or more threaded holes and side contact surfaces for the high-speed cutting insert described above in any of the options, installed in each socket and fixed with using screws

while on the supporting surfaces of the nests made cylindrical protrusions included in the cylindrical selection of high-speed cutting inserts.

Brief Description of the Drawings

For a better understanding, but only as an example, the invention will be described with reference to the attached drawings, which depict a high-speed cutting insert and a high-speed cutting tool. Wherein:

in FIG. 1 is a perspective view of a high speed cutting insert in accordance with the present invention;

in FIG. 2 shows a side view of the high speed cutting insert shown in FIG. one;

in FIG. 3 shows a bottom view A of the high speed cutting insert shown in FIG. one;

in FIG. 4 is a perspective view of a high speed cutting tool;

in FIG. 5 is a perspective view of a slot for securing a high speed cutting insert of the high speed cutting tool shown in FIG. four;

in FIG. 6 is a cross-sectional view taken along line CC of the high-speed cutting tool of FIG. four.

Detailed Description of Drawings

Consider FIG. 1-6, which depicts a high-speed cutting tool and a cutting insert.

In accordance with the present invention, the proposed high-speed cutting insert 10 is multifaceted and indexable. It is preferably made by shaped or injection molding and sintering carbide powders.

High speed insert 10 includes:

the upper working 12 and the opposite lower base 14 of the surface, the peripheral side surface located between them, including the main side 16 and auxiliary side 18 surfaces located at an acute internal angle α to the lower base surface 14,

at least one or more fixing through holes 20 extending between the upper working 12 and lower base 14 surfaces, with samples 22 made in the lower parts of the fixing through holes 20 and open to the lower base surface 14,

at least two cutting edges 24, with each cutting edge 24 containing successively mated portions of the main 26 and auxiliary 28 cutting edges directed at sharp internal angles β1 and β2, respectively, to the lower base surface 14 with the formation on the top of the cutting edges 24 corner cutting edges 30,

the upper working surface 12 includes front surfaces 32 adjacent respectively to each cutting edge 24 and extending from the cutting edges 24 mainly inward towards the upper working surface 12,

In accordance with the proposed invention, a wear-resistant coating (36) is applied to the lower base surface (14) with a high coefficient of rest or sliding friction paired with the material of the supporting surfaces (52) of the seats (58) of the high-speed cutting tool, larger than the sliding friction coefficient front surfaces (32).

According to one preferred embodiment, the lower base surface 14 is in particular coated with a wear-resistant coating of titanium aluminum nitride (Ti Al Ν), or aluminum titanium nitride (Al Ti Ν), or titanium (Ti).

According to another preferred embodiment, the angular cutting edges 30 are made with a radial rounding, or straight, or in the form of parts of second-order surfaces, in particular a cylinder, or an ellipsoid of revolution, or a cone, or a hyperboloid of revolution, or a paraboloid of revolution.

According to another preferred embodiment, the chamfers 38 are made on the auxiliary side surfaces 18.

According to another preferred embodiment, the bevels 40 are formed on the main side surfaces 16 at an acute internal angle to the lower base surface 14, this angle being uneven along the portion of the main cutting edge 26.

Consider also FIG. 4-6, where in accordance with the present invention depicts a high-speed cutting tool. It can be made, in particular, in the form of an end mill 42. According to the proposed invention, it has:

case 44 with a working surface 46 located around the axis of rotation 48, in which the slots 50 are made,

wherein each socket 50 has a supporting surface 52 with one or more threaded holes 54 and side contact surfaces 56 for the high-speed cutting insert 10 described above in any of the embodiments, mounted in each socket 50 and secured with screws 58,

while on the supporting surfaces 52 of the nests 50 are made cylindrical protrusions 60 included in the cylindrical samples 22 of high-speed cutting inserts 10.

The proposed invention works as follows.

High-speed cutting inserts 10 are installed in the nests 50 of the high-speed cutting tool, made in the form of an end mill 42, and fastened with screws 58. These plates 10 and the nests 50 of the high-speed cutting tool do not have V-shaped grooves, which ensures an increase in their strength. At the same time, the front and rear surfaces of modern high-speed cutting inserts are usually coated with a diamond-like wear-resistant coating with a low coefficient of sliding friction equal to 0.1-0.2, which provides a significant increase in the resistance of the cutting edges of the insert.

Moreover, this coating is usually technologically applied to all surfaces of the plate, including its lower base surface 14, which significantly reduces the reliability of fixing the plate.

In accordance with the proposed design of the high-speed cutting insert, on its lower base surface 14, in particular, a wear-resistant coating is made of titanium-aluminum-nitride (Ti Al Ν), or aluminum-titanium nitride (Al Ti Ν), or of titanium (Ti ), which have a high coefficient of sliding friction equal to 0.6-0.7, many times higher than the coefficient of sliding friction for both the front surfaces and the base material of the plate.

When fastening high-speed cutting inserts 10 with screws 58 between their lower base surfaces 14 and the supporting surfaces 52 of the seats 50, significant frictional forces Ftr arise due to the high friction coefficients of the contacting surfaces. When milling, for example, products from aluminum or its alloys at the moment of loading of the cutting edges 24, these forces increase significantly, which improves the positioning of high-speed cutting inserts 10 during the cutting process.

When the cutting edges 24 exit the cutting zone, the high-speed cutting inserts 10 are affected by a significant centrifugal force (Fig. 6), the resultant of which Fс is applied in the center of mass M of the high-speed cutting insert 10.

In this case, the high-speed cutting insert 10 is held in the pocket 50 due to the fixing force Fв from the screws 58 and the friction forces Фтр, which arise between the supporting surfaces 52 of the seats 50 and the lower base surfaces 14 of the plates.

Due to the fact that a wear-resistant coating with a high coefficient of friction is applied to the lower base surface 14, the friction force Ftr is significant, many times higher than the value of the friction forces for the wear-resistant coating of the front surfaces and the base material of the plate without a wear-resistant coating.

This allows you to significantly reduce the load from the centrifugal forces Fts on the mounting screws 58 and thereby increase the reliability of the fastening of the high-speed cutting insert 10 at the time of its exit from the cutting zone.

Thus, the proposed design of a high-speed cutting insert 10 and a high-speed cutting tool for its use, for example, in the processing of products from aluminum and its alloys with high cutting speeds, can improve the fastening reliability and mechanical strength of the high-speed cutting plate 10.

Although the present invention has been described with a certain degree of detail, various changes and modifications can be made without departing from the spirit and scope of the invention set forth in the following claims.

Claims (6)

1. The cutting insert (10) installed in the nests of the high-speed cutting tool and containing the upper working (12) and the underlying lower base (14) surfaces, the peripheral side surface located between them, including the main side (16) and auxiliary side (18) surfaces located at an acute internal angle (α) to the lower base surface (14), at least one or more fixing through holes (20) passing between the upper working (12) and lower base (14) surfaces, with cylindrical selection and (22) made in the lower parts of the fixing through holes (20) and open to the lower base surface (14), at least two cutting edges (24), each of which contains sections of the main (26) and auxiliary (28) cutting edges directed at sharp internal angles (β1, β2) to the lower base surface (14) with the formation on the top of the cutting edges (24) of angular cutting edges (30), while the upper working surface (12) includes front surfaces (32) adjacent to each cutting edge (24) and extending from them inward towards the upper working surface (12), characterized in that the lower base surface (14) is made with a wear-resistant coating (36), the coefficient of friction of rest or sliding of which is paired with the material of the supporting surfaces ( 52) the nests (50) of the high-speed cutting tool are larger than the sliding friction coefficient of the front (32) surfaces of the cutting insert. 2. The cutting insert (10) according to claim 1, characterized in that the wear-resistant coating is made of titanium-aluminum-nitride (Ti Al Ν), or aluminum-titanium nitride (Al Ti Ν), or of titanium (Ti). 3. A cutting insert according to claim 1, characterized in that the angular cutting edges (30) are made with a radial rounding, straight or in the form of parts of second-order surfaces, in particular a cylinder or an ellipsoid of revolution, a cone, a hyperboloid of revolution or a paraboloid of revolution. 4. The cutting insert according to claim 1, characterized in that on the minor side surfaces (18) there are made cleaning chamfers (38). 5. The cutting insert according to claim 1, characterized in that the bevels (40) are made on the main side surfaces (16), which are located at an acute internal angle to the lower base surface (14), which is uneven along the portion of the main cutting edge (26). 6. A high-speed cutting tool made in the form of an end mill (42), comprising a body (44) with a working surface (46) located around the axis of rotation (48), in which the nests (50) are made, with each nest (50) has a supporting surface (52) with one or more threaded holes (54) and side contact surfaces (56) for mounting the cutting insert (10) according to any one of paragraphs. 1-5, fixed with screws (58), while the supporting surfaces (52) of the nests (50) are made with cylindrical protrusions (60) included in the cylindrical selection (22) of the cutting inserts (10).

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