Milling tool

Abstract

A milling tool for face milling includes a tool body and a plurality of cutting members arranged successively along a periphery of the tool body. Each cutting member includes a main cutting edge provided for a roughing operation and a subset having a first, a second and a third secondary cutting edge provided for a finishing operation. The first and third secondary cutting edges extend in a direction perpendicular to an axial direction and the second secondary cutting edge extends between the first and third secondary cutting edge. The main cutting edges are situated at the same radial position and the first secondary cutting edges are situated at the same axial position. A first end point of the second secondary cutting edges successively progress radially inward and a second end point of the second secondary cutting edges successively progress radially inward and axially outward along the periphery of the tool body.

Claims

1. A milling tool arranged for face milling of a work piece, said milling tool comprising: a tool body having a central rotation axis defining an axial direction, the tool body including a periphery, the periphery including an envelope surface extending along the axial direction and a front surface extending along a radial direction; and a plurality of cutting members arranged successively along the periphery of said tool body for radial and axial machining of said work piece, each of said plurality of cutting members including a rake face, a clearance surface, and a main cutting edge arranged for a roughing operation, wherein said main cutting edge is formed between said rake face and said clearance surface and extends along the axial direction and the envelope surface of the tool body, and wherein at least a subset of said cutting members, said subset having at least two cutting members, includes a plurality of secondary cutting edges arranged for a finishing operation, wherein said plurality of secondary cutting edges are formed between said rake face and said clearance surface along the front surface of the tool body, and wherein each of said plurality of secondary cutting edges includes at least a first secondary cutting edge, a second secondary cutting edge, and a third secondary cutting edge, wherein said first and third secondary cutting edges extend in a direction perpendicular to said axial direction and said second secondary cutting edge extends between said first and said third secondary cutting edges, the main cutting edges of the cutting members of said subset being situated at a same radial position along the envelope surface of the tool body, said first secondary cutting edges being situated at a same axial position, wherein said first secondary cutting edge is connected to said main cutting edge via a corner cutting edge, such that an axial position of said corner cutting edge determines a relative amount of material being machined by the main cutting edge and the plurality of secondary cutting edges respectively of a total depth of cut of the milling tool, and wherein a first end point of each of said second secondary cutting edges successively progresses radially inward relative to a succeeding cutting member of said subset, and a second end point of each of said second secondary cutting edges successively progresses radially inward and axially outward from the front surface along a periphery of said front surface of said tool body relative to the succeeding cutting member of said subset, such that the second secondary cutting edge of the succeeding cutting member has a greater length and is situated closer to the central rotation axis of said tool body than the second secondary cutting edge of a preceding cutting member along the periphery of said front surface of the tool body.

2. The milling tool according to claim 1, wherein the number of cutting members including said subset equals a total number of cutting members arranged along the periphery of said tool body.

3. The milling tool according to claim 1, wherein the corner cutting edge is a chamfer cutting edge.

4. The milling tool according to claim 1, wherein the cutting members are arranged such that the secondary cutting edges form a radial rake angle in a range of 10 to +10, with respect to the radial direction defined between the main cutting edge and the axis of rotation of the milling tool, and wherein the main cutting edge extends in a plane parallel to the axial direction at an axial rake angle in a range of 10 to +10 with respect to the axial direction.

5. The milling tool according to claim 1, wherein said first end point of said second secondary cutting edges successively progress radially inward by a first radial distance between subsequent cutting members and said second end point of each said second secondary cutting edges successively progress radially inward by a second radial distance between subsequent cutting members, so that each second secondary cutting edge extends axially outwards and radially inwards by being inclined at an acute angle in relation to the central rotation axis, wherein the acute inclination angle is the same on all of the second secondary cutting edges.

6. The milling tool according to claim 5, wherein at least one of said first radial distance and said second radial distance is in the range 0.1-0.5 mm.

7. The milling tool according to claim 1, wherein said second end point of said second secondary cutting edges successively progress axially outwards by a fixed axial distance between subsequent cutting members.

8. The milling tool according to claim 1, wherein the second end point of the second secondary cutting edges successively progress axially outwards by an axial distance between subsequent cutting members, and wherein the second end point of the second secondary cutting edges successively progress axially outwards by another axial distance between the subsequent cutting members, and wherein said axial distances are non-equal.

9. The milling tool according to claim 1, wherein said main cutting edge extends in the axial direction at the periphery of the envelope surface of the tool body, such that an entering angle of the main cutting edge is 90.

10. The milling tool according to claim 1, wherein a cutting depth of the main cutting edge is in the range 0.1-4 mm.

11. The milling tool according to claim 1, wherein the total cutting depth including the main cutting edge and the secondary cutting edges of the milling tool is in the range 0.2-5 mm.

12. The milling tool according to claim 1, wherein the plurality of cutting members are formed by cutting inserts being brazed onto the tool body the main and secondary cutting edges being formed of a PCD material.

13. The milling tool according to claim 1, wherein the diameter of the milling tool is from 12 to 100 mm.

14. The milling tool according to claim 1, wherein the angular distance between adjacent cutting member of the milling tool is in the range 10-90.

15. A kit of replaceable cutting inserts configured to be arranged successively along a periphery of a tool body of a milling tool for face milling, said milling tool including a tool body having a central rotation axis defining an axial direction, said periphery including an envelope surface extending along the axial direction and a front surface extending along a radial direction, each of said cutting inserts including a rake face, a clearance surface, and a main cutting edge provided for a roughing operation, wherein said main cutting edge is formed between said rake face and said clearance surface and extends along the axial direction and the envelope surface of the tool body, when arranged on the tool body, and wherein the cutting inserts of a subset of the cutting inserts includes at least two cutting inserts including a plurality of secondary cutting edges provided for a finishing operation, wherein said plurality of secondary cutting edges are formed between said rake face and said clearance surface along the front surface of the tool body, and wherein each of said plurality of secondary cutting edges includes at least a first secondary cutting edge, a second secondary cutting edge, and a third secondary cutting edge, wherein said first and third secondary cutting edges, when arranged on the tool body, extend in a direction perpendicular to said axial direction and said second secondary cutting edges extend between said first and said third secondary cutting edge, wherein, when arranged on the tool body, the main cutting edges of the cutting inserts are situated at a same radial position along the envelope surface of the tool body, said first secondary cutting edges being situated at a same axial position and wherein, when arranged on the tool body, a first end point of each of said second secondary cutting edges successively progresses radially inward relative to a succeeding cutting insert of said subset, and a second end point of each of said second secondary cutting edges successively progresses radially inward and axially outward from the front surface along a periphery of said front surface of said tool body relative to the succeeding cutting insert of said subset, such that the second secondary cutting edge of the succeeding cutting insert has a greater length and is situated closer to the central rotation axis of said tool body than the second secondary cutting edge of a preceding cutting insert along said front surface of the tool body.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be better understood through the following illustrative and non-limiting detailed description of preferred embodiments, with reference to the appended drawings, on which:

(2) FIG. 1a is a perspective view of a milling tool according to one embodiment;

(3) FIG. 1b is a bottom view of a milling tool according to one embodiment;

(4) FIG. 1c is a side view of a milling tool according to one embodiment;

(5) FIG. 2a is a perspective view of a milling tool according to one embodiment;

(6) FIG. 2b is a bottom view of a milling tool according to another embodiment;

(7) FIG. 2c is a side view of a milling tool according to another embodiment;

(8) FIGS. 3-3h show a cutting member of the milling tool according to one embodiment in different views.

(9) FIG. 4a is a detailed perspective view of the milling tool showing a number of cutting members arranged on the tool body;

(10) FIG. 4b is a schematic view indicating the progression of the secondary cutting edges of the cutting member along the periphery of the cutting tool;

(11) All figures are schematic, not necessarily to scale, and generally only show parts which are necessary in order to elucidate the invention, wherein other parts may be omitted or merely suggested.

DETAILED DESCRIPTION OF EMBODIMENTS

(12) A milling tool according to one exemplary embodiment is shown in three different views in FIG. 1a-1c. The tool 1 comprises a tool body 10 having an envelope surface 11 extending along an axial extension A and a front surface 12 extending along a radial extension R. The illustrated exemplary embodiment of FIG. 1a-c is adapted for face milling and comprises 10 cutting members 100 arranged along the periphery of the tool body, the design of which will be descried in greater detail in the following. The cutting members are fixedly attached to the tool body, in the illustrated case by means of brazing.

(13) As may be seen in FIG. 1b, the cutting members are arranged at a radial rake angle , i.e. such that for example the third secondary cutting edge extends at the radial rake angle .sub.1 with respect to a radial direction defined for example from the first end point of the third secondary cutting edge to the centre of the milling tool. In general such a radial rake angle .sub.1 may belong to the range 10 to +10. However, in the disclosed embodiment, the radial rake angle is positive in order to provide an easy/light cutting action on the main cutting edge. With respect to the axial direction, the cutting members are arranged such that the main cutting edge extends in a plane parallel to the axial direction but at an axial rake angle .sub.2 with respect to the axial direction, in general such an axial rake angle .sub.2 may belong to the range 10 to +10 (shown in FIG. 1c). The disclosed embodiment also discloses a positive angle on the axial rake angle in order to provide a positive inclination on the main cutting edge, which further contributes to the easy/light cutting action on the main cutting edge. The positive axial rake angle may also provide easy/light cutting action on the secondary cutting edges.

(14) A second milling tool according to a second exemplary embodiment is shown in three different views in FIG. 2a-c. The tool 1 comprises a tool body 10 having an envelope surface 11 extending along an axial extension A and a front surface 12 extending along a radial extension R. The illustrated exemplary embodiment of FIG. 2a-c is adapted for shoulder milling and comprises 8 cutting members 100 arranged along the periphery of the tool body 10. The cutting members are fixedly attached to the tool body, in the illustrated case by means of brazing. Similarly to the embodiment illustrated in FIG. 1a-c, the cutting members are arranged at a radial rake angle .sub.1, in general such an angle may belong to the range 10 to +10 (Illustrated in FIG. 2b). Also likewise, the cutting members are arranged such that the main cutting edge extends in a plane parallel to the axial direction but at an axial rake angle .sub.2 with respect to the axial direction, in general such an axial rake angle .sub.2 may belong to the range 10 to +10 (shown in FIG. 2c). Furthermore, as mentioned in the previous embodiment, both the radial and axial rake angles are positive in this embodiment to provide easy/light cutting action on the main cutting edge and the secondary cutting edges.

(15) In the illustrated exemplary embodiments in FIGS. 1a-c and 2a-c, all cutting members arranged along the periphery of the cutting tool comprise the first, second and third secondary cutting edges.

(16) Turning to FIG. 3-3h, the design of an exemplary cutting member of the tool body will be described in detail.

(17) FIG. 3 is a perspective view of a cutting member 100 according to one exemplary embodiment, the cutting member comprising a rake face 110, a clearance surface 120 and a main cutting edge 130 for roughing operation. The main cutting edge 130 is formed between the rake face 110 and the clearance surface 120 and is adapted to, when arranged on the tool body 10, extend in a direction parallel to the axis A which in the illustrated case coincides with the axis of rotation of the milling tool, such that the entering angle of the main cutting edge is 90.

(18) Three secondary cutting edges for finishing operation are formed between the rake face 110 and the clearance surface 120, a first secondary cutting edge 140, a second secondary cutting edge 150 and a third secondary cutting edge 160. The first and third secondary cutting edges 140, 160 are adapted to extend, when arranged on the tool body, in a direction perpendicular to the axis of rotation, i.e. in a radial direction, whereas the second secondary cutting edge 150 extends between the first- and third secondary cutting edge, i.e. between a respective end point 141, 162 of the first- and third secondary cutting edge respectively.

(19) The main cutting edge 130 is connected to the first secondary cutting edge 140 via a corner cutting edge 170, in the illustrated case a corner chamfer edge 170.

(20) The total cutting depth of the cutting member 100 is defined by the total height of the cutting member, i.e. the main cutting edge 130, the corner chamfer edge 170 and the secondary cutting edges 140, 150, 160. Accordingly, by means of a shift of the axial position of the corner chamfer cutting edge 170, the relative amount of material machined during the roughing operation and the finishing operation (provided by the secondary cutting edges 140, 150, 160) respectively may be determined.

(21) FIG. 3a is a perspective view of the cutting member viewed from an opposite direction as compared to FIG. 3, i.e. showing a bottom side 111 opposite to the rake face adapted to, when arranged on the tool body, face a seat of the tool body. FIG. 3b is a side view of the cutting member, showing a clearance angle of the main cutting edge, in general, the clearance angle belongs to the range 0-20. FIG. 3c shows a clearance angle of the third secondary cutting edge, in general the clearance angle belongs to the range 0-20. FIG. 3e is a side view, opposite to FIG. 3c, (again showing the clearance angle of the third secondary cutting edge), whereas FIG. 3g is a side view of the cutting member, also showing the clearance angle of the main cutting edge. FIG. 3h is showing a cross section of the cutting member comprising an upper part of PCD material on a lower part of cemented carbide material making the cutting member particularly suitable for face milling in aluminium.

(22) FIGS. 4a and 4b are showing the progression of the secondary cutting edges of the cutting members 100 along the periphery of the front surface of the tool body, i.e. between succeeding cutting members for an exemplary embodiment, wherein FIG. 4a shows a first cutting member 100 arranged on a tool body 10, and FIG. 4b shows a superimposed view of all the secondary cutting edges along the periphery of the tool body (i.e. the progression).

(23) As explained in the foregoing, the main cutting edge 130 of the cutting member 100, extending in a plane parallel to the axial direction A when arranged on the tool body as shown in FIG. 4a, is connected to the first secondary cutting edge 140 via the corner chamfer cutting edge 170. The first secondary cutting edge is adapted to extend, when arranged on the tool body as shown in FIG. 4a, in a direction perpendicular to the axial direction (i.e. in a plane perpendicular to the axis of rotation). The extension of the main cutting edge 130 and the corner chamfer edge respectively is the same, i.e., remain constant, over the cutting members along the periphery of the cutting tool.

(24) The corner chamfer cutting edge 170 joins a first endpoint 141 of the first secondary cutting edge 140. The position of this first end point 141 of the first secondary cutting edge, as well as the axial position of the plane along which the first secondary cutting edge extends also remains constant over the cutting members along the periphery. Accordingly, the extension of the first secondary cutting edge is always perpendicular to the axial direction and the first secondary edge remains in the same plane perpendicular to the axial of rotation.

(25) The second and third secondary cutting edges 150, 160 however change in terms of radial and/or axial extension, i.e. progress, along the periphery of the tool body.

(26) The second secondary cutting edge 150, extending between the end points 151, 152, transforms between cutting inserts along the periphery of the tool such that the first end point 151 successively progress radially inward, and the second end point of the second secondary cutting edge successively progress radially inward and axially outwards. Consequently, as indicated in FIG. 4b, a second secondary cutting edge of a succeeding cutting insert has a greater length and is situated closer to the central rotation axis of said tool body than a second secondary cutting edge of a preceding cutting member along the periphery of said front surface of the tool body.

(27) The third secondary cutting edges 160, extending in a plane perpendicular to the axial direction between endpoints 161 and 162, changes, i.e. progresses, along the periphery of the tool body according to the following: The first end point 161, coinciding with the second end point 152 of the second secondary cutting edge progresses, i.e., radially inwards and axially outwards for each cutting member along the periphery, whereas the outer end point 162 only moves axially outwards for each successive cutting member. Consequently, a third secondary cutting edge of a succeeding cutting insert has a shorter length and extends in a plane perpendicular to the axial direction, i.e. situated at an axial position further from the front surface along the central rotation axis of the tool body than a third secondary cutting edge of a preceding cutting member along the periphery of the front surface of the tool body. The third secondary cutting edge of each cutting member however always extends in a respective plane perpendicular to the axial of rotation.

(28) While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. The skilled person understands that many modifications, variations and alterations are conceivable within the scope as defined in the appended claims.

(29) Additionally, variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word comprising does not exclude other elements or steps, and the indefinite article a or an does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope of the claims.