Monolithic ceramic end mill cutter set having a helix angle in the interval of 28° to 43°

Abstract

The invention is a monolithic end-mill cutter set (A) that can be made of ceramic and/or other materials having high strength and toughness and comprising a shank part (B) along a longitudinal axis (4) and a cutter part (C), comprising: a cutting diameter (1) varying between 2 to 20 mm, at least one web thickness (18) found at a blade (26) part, at least one helix angle (10) having a cutting edge (13) thereon, a core diameter (16) that is at least 0.7 times the cutting diameter (1), at least one corner radius (5) found at the tip part of the blades (26) between the flutes (9) and axial and positive radial rake angles (17) at which cutting operation is made. It has a wide helix angle interval and a positive rake angle. Titanium Aluminum Nitride TiAlN coating can be made on the monolithic end-mill cutter set (A) via PVD coating method in order to extend the service life of the end-mill cutter set (A), increase the abrasion resistance, and minimize the problem of sticking of rake on the cutter set (joining).

Claims

1. A monolithic end-mill cutter set (A) made of ceramic and comprising a shank part (B) along a longitudinal axis (4) and a cutter part (C), characterized in that the end mill cutter set comprises: a cutting diameter (1) varying between 2 to 20 mm, at least one web thickness (18) found at a blade (26) part, at least one helix angle (10) having a cutting edge (13) thereon, a core diameter (16) that is at least 0.7 times the cutting diameter (1), the helix angle (10) having a range from 28 to 43 degrees, depending on characteristics of a material to be processed, at least one corner radius (5) found at a tip part of the blade (26) part between a plurality of flutes (9) and an axial rake angle and positive radial rake angle (17) at which a cutting operation is made; wherein the radial rake angle (17) is between 0 to +5 interval; wherein the axial rake angle is between 3 to +5 interval; and wherein an end rake (28) at a front part is between 6 to +6 interval.

2. The end-mill cutter set (A) according to claim 1, characterized in that, a helical structure found at edges of the plurality of flutes (9) along the longitudinal axis (4) continues in a longitudinally helical structure and ends at the web thickness (18) found at the blade (26) part.

3. The end-mill cutter set (A) according to claim 1, characterized in that, a helix length (3) is about 1 to 2 times the cutting diameter (1).

4. The end-mill cutter set (A) according to claim 1, characterized in that, a number of the plurality of flutes (9) vary between 2 to 8, depending on the cutting diameter (1).

5. The end-mill cutter set (A) according to claim 1, characterized in that, the corner radius (5) is between 0.01 to 0.4 times of the cutting diameter (1).

6. The end-mill cutter set (A) according to claim 1, characterized in that, the helix angle (10) varies from 28 to 43, depending on characteristics of a material to be machined.

7. The end-mill cutter set (A) according to claim 1, characterized in that, a gash angle (24) is between 15 to 45 interval.

8. The end-mill cutter set (A) according to claim 1, characterized in that, a dish angle (23) at an opening part of the flutes (9) is between 1 to 3.

9. The end-mill cutter set (A) according to claim 1, characterized in that, said cutter set (A) comprises a Titanium Aluminium Nitride (TiAlN) coating via a PVD coating.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) For better understanding of the embodiment of the present invention and its advantages with its additional components, it should be evaluated together with below described figures.

(2) FIG. 1; is the side profile view of the 4-blade embodiment of the monolithic end-mill cutter set according to the invention.

(3) FIG. 2; is the side profile view of the 6-blade embodiment of the monolithic end-mill cutter set according to the invention.

(4) FIG. 3; is the side profile view of the monolithic end-mill cutter set according to the invention; showing the cutting edges, blades, primary relief angle adjacent to the helix angle and the secondary relief angle.

(5) FIG. 4; is the side profile view of the monolithic end-mill cutter set according to the invention; showing the width of primary relief land and axial width of secondary relief land.

(6) FIG. 5; is the side profile view of the monolithic end-mill cutter set according to the invention; showing the axial primary relief angle, axial secondary relief angle, and the dish angle dimensioned according to the plain surface that is tangent to the cutting end.

(7) FIG. 6; is the view of the front part of the monolithic end-mill cutter set according to the invention; showing the web thickness, gash angle, pods and end rake.

(8) FIG. 7; is the front profile view of the front part of the monolithic end-mill cutter set according to the invention; showing the radial primary relief angle and radial secondary relief angles found beside the blade helix angle, the core diameter, and the radial rake angle.

(9) FIG. 8; is a three-dimensional view of a preferred embodiment of the monolithic end-mill cutter set according to the invention.

REFERENCE NUMBERS

(10) A: End-mill cutter set B: Shank part C: Cutter part 1. Cutting diameter 2. Shank diameter 3. Helix length 4. Longitudinal axis 5. Corner radius 6. Cutting end 7. Total length 8. Shank length 9. Flute 10. Helix angle 11. Primary relief angle 12. Secondary relief angle 13. Cutting edge 14. Width of primary relief land 15. Width of secondary relief land 16. Core diameter 17. Radial rake angle 18. Web thickness 19. Axial primary relief angle 20. Axial secondary relief angle 21. Radial primary relief angle 22. Radial secondary relief angle 23. Dish angle 24. Gash angle 26. Blades 27. Cutting edge tangent 28. End rake

DETAILED DESCRIPTION OF THE INVENTION

(11) In this detailed description, the preferred embodiments of the end-mill cutter set (A) according to the invention are only disclosed for better understanding of the subject without forming any limiting effect.

(12) The present invention relates to monolithic end-mill cutter sets (A) that can be made of ceramic or such other materials having high hardness and toughness and to machining methods of such end-mill cutter sets (A). The improvement provided with the invention is production of end-mill cutter set (A) with a wide helix angle (10) and additionally, extending the expected life of the end-mill cutter set (A), improving its abrasion resistance, and making Titanium Aluminium Nitride (TiAlN) coating via PVD coating method in order to minimize sticking of rakes on the end-mill cutter set (A).

(13) FIG. 1 shows the side profile view of the preferably 4-flute embodiment of the monolithic end-mill cutter set (A) according to the invention, while FIG. 2 shows the side profile view of the preferably 6-flute embodiment. The end-mill cutter set (A) basically consists of a shank part (B) fixed to the tool holder and a cutter part (C) processing the material surface via rotational motion. The end-mill cutter set (A) has a cylindrical form with a longitudinal axis, and it is produced monolithically from a ceramic material called SiAlON. FIG. 8 shows a three-dimensional view of a preferred embodiment of the monolithic end-mill cutter set (A) according to the invention.

(14) As can be seen from FIGS. 1 and 2, the SiAlON monolithic end-mill cutter set (A) has a cutting diameter (1) comprising blades (26) along the longitudinal axis (4) of its cylindrical body, and a diameter of the shank diameter (2) that is fixed to the holder. While the cutting diameter (1) varies between 2 to 20 mm, the helix length (3) defining the cutting length can be between 1 to 2 times of the cutting diameter (1).

(15) The total length (7) of the end-mill cutter set (A) is equal to the summation of the helix length (3) and the shank length (8). At the tip of the cutter part (C), cutting end (6) and the corner radius (5) structures shown in FIG. 1 are found.

(16) The shank diameter (2) and the cutting diameters (1) can be same or different from each other in the end-mill cutter set (A). The adjacent blades (26) arranged on the helix angle (10) of the end-mill cutter set (A) are separated from each other via flute (9) grooves. The blades (26) extending along the longitudinal axis (4) end at the end-mill cutter set (A) cutting end (6).

(17) The core diameter (16) of the end-mill cutter set (A) can be about 0.70-0.75 times the cutting diameter (1). The blades (26) have a radial rake angle (17) where cutting operation is made and an axial rake angle. The radial rake angle (17) has a positive angle.

(18) In the side profile view of the monolithic end-mill cutter set (A) according to the invention given in FIG. 3; the cutting edges (13), 2 to 8 blades, or in other words flutes (9), the primary relief angle (11) adjacent to the helix angle (10), and the secondary relief angle (12) can be seen. In FIG. 4, the width of axial primary relief land (14) and the width of axial secondary relief land (15) corresponding to the primary relief angle (11) and the secondary relief angle (12), respectively, are shown.

(19) In FIG. 5, the axial primary gap angle (19), the axial secondary gap angle (20), and dish angle (23) dimensioned according to the cutting edge tangent (27) (cutting edge tangent) that is tangent to the cutting end (6) in the front part of the end mill (A) are shown.

(20) In the view of the front part of the monolithic end-mill cutter set (A) according to the invention, given in FIG. 6; the web thickness (18) corresponding to the gap between the flutes (9) found at the cutting end (6), the gash angle (24) corresponding to the angle found at the sides of the blades (26) found at each helix angle (10), and the number of the flutes (9) found at the ends can be seen. FIG. 6 also shows the end rake (28) indicating the end of the radial rake angle (17).

(21) In the front profile view of the front part of the monolithic end-mill cutter set (A) according to the invention, given in FIG. 7; the radial primary relief angle (21) and radial secondary relief angles (22) found beside the blade (26) helix angle (10) can be seen.

(22) The end-mill cutter set (A) according to the invention: The length of the cutter part (C), which has a helix length (3) that is one to two times the cutting diameter (1), is shorter than the shank length (8) of the shank part (B), The core diameter (16) is at least 0.7 times the cutting diameter (1), The helix angle (10) is between 28 to 43 around its axis. The number of flutes (9) are between 2 to 8. The end rake (28) of the rake angle is between 6 to +6 interval. The corner radius (5) is about 0.010-0.4 times the cutting diameter (1). Radial rake angle (17) is between 0 to +6. Axial rake angle is approximately between 3 to +5. The dish angle (23) varies between 1 to 3. The gash angle (24) is between 15 to 45 interval. Moreover, the cutting diameter (1) is preferred to remain constant along the helix length (3), but it can also be tapered along the helix length (3). The cutting diameter (1) can have diameters varying between 2 to 20 millimeters and the number of flutes (9) may increase as the cutting diameter (1) increases.

(23) In the end-mill cutter set (A) according to the invention, Silisium Nitride (Si.sub.3N.sub.4) based ceramics, alumin-added silisium carbide whisker, silisium carbide, alpha/beta (20:80 to 80:20) SiAlON (Si3N4+Al.sub.2O.sub.3+AlN+Y.sub.2O.sub.3+Sm.sub.2O.sub.3+CaCO.sub.3), Al.sub.2O.sub.3 can be used as ceramic material.

(24) The operation steps for the production of the end-mill cutter set (A) according to the invention are as follows: SiAlON material is brought into a rod form via sintering methods. The diameter of the rod-shaped ceramic material is machined. Diameter machined rod material is brought into milling cutter form via channel machining. The end-mill cutter set (A) is subjected to corner rounding finishing operation in order to eliminate the micro cracks found at the helix edges. Coating is made on the cutter set, but it can also be used without coating.

(25) During milling operation, the problem of the removed rake joining on the ceramic cutter tip surface (sticking of rake on the cutting set) due to formation of high temperature on the surface of the piece is encountered. PVD TiAlN coating is made in order to extend the service life of the ceramic end-mill cutter set (A) and minimize the sticking problem of rakes on the cutting set.

(26) It is known that the AlN phase having hexagonal lattice structure provides better sticking on the ceramic material surface than the cubical lattice TlN phase. This means that interatomic bonds are formed between the TiAlN coating and the ceramic material. By means of the interatomic bonds, the cutter set (A) can easily be polarized during coating. Following coating, the surface hardness and surface roughness of the ceramic material is increased. As a result trials, it is found out that the rake sticking problem is reduced on the coated surface.

(27) In test studies made at anhydrous 600 m/min cutting speed at a high speed machine, machining is performed on inkonel 718 material with the end mill set (A) according to the invention and 17.6 cm.sup.3/min rake is removed from the material.

(28) The improvements provided with the end-mill cutter set (A) according to the invention are as follows: The cutting diameter (1) of the monolithic end-mill cutter set (A) having axial structure is between 2 to 20 mm, A web thickness (18) is found at the blade (26) part of the end-mill cutter set (A) and it has a helix angle (10) having a cutting edge (13) thereon, It has a core diameter (16) which is at least 0.7 times the cutting diameter (1), The helical structure found at the edges of the cutter flutes (9) along the longitudinal axis (4) continues in a longitudinally helical structure and ends at the web thickness (18) found at the blades (26) part, A corner radius (5) is found at the tip part of the blades (26) between the plurality of flutes (9) and axial and positive radial rake angles (17) are found where cutting operation is made, The helix length (3) indicating the cutting length is about 1 to 2 times of the cutting diameter (1), The number of flutes (9) vary between 2 to 8, depending on the milling cutter set (A) diameter, The corner radius (5) is between 0.01 to 0.4 times of the cutting diameter (1), The helix angle (10) varies from 28 to 43 degrees, depending on the characteristics of the material to be machined, The radial rake angle (17) is between 0 to +5 interval, the axial rake angle is between 3 to +5 interval, the gash angle (24) is between 15 to 45 interval, the rake angle end rake (28) found at the front part of the milling cutter set is between 6 to +6 interval, the dish angle (23) at the blade part of the flutes (9), that is to say, the pit angle is between 1 to 3.

(29) The tip of the end mill (A) according to the invention made of ceramic material can be used with or without coating. It is possible to produce the monolithic end-mill cutter set (A) with a wider helix angle (10) than the prior art products and to use other materials with high strength and toughness in its production, besides nickel alloys.