Patent ID: 12251766

DETAILED DESCRIPTION

Aspects and/or embodiments will now be described more fully. Like numbers refer to like elements throughout. Well-known functions or constructions will not necessarily be described in detail for brevity and/or clarity. In the following, reference is made to various inner angles. Herein, an inner angle means that the angle is seen and/or measured within a body, or at least mainly within a body, of a cutting insert.

FIGS.1a-1gillustrate different views of a cutting insert2according to a first embodiment. The cutting insert2is configured for use in a milling tool, more specifically in a square shoulder milling tool. The cutting insert2comprises a first side14, a second side16opposite to the first side14, and a circumferential surface18extending between the first side14and the second side16. The circumferential surface18comprises a first pair of opposing side surfaces10,11, and a second pair of opposing side surfaces12,13, seeFIGS.1a,1dand1g.

The first side14defines a first extension plane P1. The second side16defines a second extension plane P2. A centre axis C extends perpendicularly through the first and second extension planes P1, P2. In these embodiments, the cutting insert2comprises a through hole9for securing the cutting insert2, e.g. by means of a screw, in an insert seat of a milling tool. The through hole9extends centrally through the cutting insert2. The centre axis C extends along a centre of the through hole9. According to alternative embodiments, wherein the cutting insert does not comprise a through hole, the cutting insert may instead be secured in an insert seat of a milling tool by clamping means.

A median plane MP extends halfway between the first extension plane P1and the second extension plane P2. The median plane MP extends in parallel with the first and second extension planes P1, P2. A longitudinal plane LP extends halfway between the first pair of opposing side surfaces10,11, perpendicularly to the median plane MP and containing the centre axis C. A central plane CP extends perpendicularly to both the median plane MP and the longitudinal plane LP and contains the centre axis C. A first axis A1extends along an intersection between the median plane MP and the longitudinal plane LP. A second axis A2extends along an intersection between the median plane MP and the central plane CP. The centre axis C and the first and second axes A1, A2are shown inFIGS.1aand1d.

The first and second extension planes P1, P2, the median plane MP, the longitudinal plane LP, and the central plane CP are imaginary planes, and are shown inFIGS.1e-1g. The median plane MP extents through the entire circumferential surface18. The longitudinal plane LP extents through the second pair of opposing side surfaces12,13. The central plane CP extents through the first pair of opposing side surfaces10,11.

At the first side14the cutting insert2comprises a first surface15extending between the circumferential surface18. The first surface15may be substantially flat along parts thereof. In other parts, such as closer to cutting edges, the first surface15may be raised, e.g. in order to provide one or more rake faces. At the second side14the cutting insert2comprises a first second surface17extending between the circumferential surface18. The second surface17may be substantially flat along parts thereof. In other parts, such as closer to cutting edges, the second surface17may be raised, e.g. in order to provide one or more rake faces.

A first cutting edge20extends along an intersection between the first side14and the circumferential surface18on a first side of the longitudinal plane LP, see e.g.FIGS.1a,1c, and1g. The first cutting edge20, as seen in a view towards the first side14, i.e. in a view along the centre axis C (FIG.1f), extends along a first corner22of the cutting insert2. A second cutting edge23extends along an intersection between the second side16and the circumferential surface18on the first side of the longitudinal plane LP, see e.g.FIGS.1a-1c. The second cutting edge23, as seen in a view towards the second side16, extends along a second corner22′ of the cutting insert2.

The first cutting edge20extends along an intersection between the first side14and a first side surface10of the first pair of opposing side surfaces10,11and a first side surface12of the second pair of opposing side surfaces12,13. The second cutting edge23extends along an intersection between the second side16and the first side surface10of the first pair of opposing side surfaces10,11and a second side surface13of the second pair of opposing side surfaces12,13.

The first cutting edge20comprises a first main cutting edge24, a first corner cutting edge26, and a first auxiliary cutting edge38. The first auxiliary cutting edge38comprises a first surface-wiping secondary cutting edge28. The first main cutting edge24adjoins the first corner cutting edge26, and the first corner cutting edge26adjoins the first surface-wiping secondary cutting edge28. The second cutting edge23comprises a second main cutting edge24′, a second corner cutting edge26′, and a second auxiliary cutting edge38′. The second auxiliary cutting edge38′ comprising a second surface-wiping secondary cutting edge28′. The second main cutting edge24′ adjoins the second corner cutting edge26′ at a first end27′ of the second main cutting edge24′, and the second corner cutting edge26′ adjoins the second surface-wiping secondary cutting edge28′. The first auxiliary cutting edge38and the second auxiliary cutting edge38′ need not to have cutting ability along their respective last part close to the longitudinal plane LP. It is enough for the performance that the first surface-wiping secondary cutting edge28and a second cutting edge part39have cutting ability. The same is valid for corresponding parts of the second auxiliary cutting edge38′.

When seen along the second axis A2, in the view ofFIG.1g, the first main cutting edge24has a concave shape. The same applies to the other main cutting edges. However, the shape of the main cutting edges may also be convex or straight when seen along the second axis A2.

A third cutting edge20′ extends along an intersection between the second side16and the circumferential surface18on a second side of the longitudinal plane LP. The third cutting edge20′, as seen in a view towards the second side16, i.e. in a view along the centre axis C, extends along a third corner22′″ of the cutting insert2, see e.g.FIGS.1aand1c. The third cutting edge20′ extends along an intersection between the second side16and a second side surface11of the first pair of opposing side surfaces10,11and the first side surface12of the second pair of opposing side surfaces12,13.

The third cutting edge20′ comprises a third main cutting edge24″, a third corner cutting edge26″, and a third auxiliary cutting edge38″. The third auxiliary cutting edge38″ comprises a third surface-wiping secondary cutting edge28″: The third main cutting edge24″ adjoins the third corner cutting edge26″, and the third corner cutting edge26″ adjoins the third surface-wiping secondary cutting edge28″.

In these embodiments, the cutting insert2further comprises a fourth cutting edge23′ arranged opposite to the first and third cutting edges20,23. The fourth cutting edge23′ extends along an intersection between the first side14and the second side surface11of the first pair of opposing side surfaces10,11and the second side surface13of the second pair of opposing side surfaces12,13.

In these embodiments, the insert2has 180° rotational symmetry with respect to rotation about each of the second axis A2, the first axis A1, and the centre axis C. According to alternative embodiments, wherein the cutting insert has less than four cutting edges, the insert may have 180° rotational symmetry with respect to rotation about the second axis A2.

In these embodiments, the cutting insert2is double-sided and four times indexable, i.e. the cutting insert2comprises four identical cutting edges20,23,20′,23′ in total, such that the cutting insert2can be mounted in four different index positions in the square shoulder milling tool, to provide one active cutting edge at a time for milling a workpiece.

For each of the cutting edges20,23,20′,23′ the following applies. When arranged in the shoulder milling tool, the main cutting edge24is extending in an axial direction of the shoulder milling tool and is fed into a workpiece, in a radial direction of the shoulder milling tool. The auxiliary cutting edge38and the surface-wiping secondary cutting edge28is extending in a radial direction of the shoulder milling tool. In a shoulder milling operation, the main cutting edge24performs a major cut into the workpiece, while the surface-wiping secondary cutting edge28only performs a shallow surface smoothing cut. The auxiliary cutting edge38and the surface-wiping secondary cutting edge28is inclined in relation to the median plane MP such that a distance to the median plane MP increases in a direction away from the longitudinal plane LP and toward the corner cutting edge26. Accordingly, close to the corner cutting edge26the auxiliary cutting edge38extends farther from the median plane MP than towards the longitudinal plane LP.

The second side surface11of the first pair of opposing side surfaces10,11comprises a first radial abutment face61and a second radial abutment face62, see e.g.FIG.1d. The first radial abutment face61is sandwiched from opposite sides between the second side16of the cutting insert2and the second radial abutment face62. In the same way, the second radial abutment face62is sandwiched from opposite sides between the first side14of the cutting insert2and the first radial abutment face61. There is a smoothly curved transition between the first and second radial abutment face. The first and second radial abutment faces are tangentially connected to the smoothly curved transition. The first radial abutment face61of the cutting insert2, according to the first embodiment, is arranged and extends on a first side of the median plane MP towards the second side16, see e.g.FIG.1g. The second radial abutment face62of the cutting insert2, according to the first embodiment, is arranged and extends on a second side of the median plane MP towards the first side14. The smoothly curved transition between the first and second radial abutment face is intersected by the median plane MP. The first radial abutment face61has an increasing width when moving along the first radial abutment face61away from the second axial abutment face32′, i.e. in a direction from the second side surface13of the second pair of opposing side surfaces12,13towards the first side surface12of the second pair of opposing side surfaces, see e.g.FIG.1dandFIG.1g. Thus, the first radial abutment face61has an increased width in the area radially inwardly from the first corner cutting edge26and the first end27of the first main cutting edge24. The width is measured in a direction from the first side14perpendicularly towards the second extension plane P2.

The first side surface10of the first pair of opposing side surfaces10,11comprises a third radial abutment face63and a fourth radial abutment face64, see e.g.FIG.1a. The third radial abutment face63is sandwiched from opposite sides between the first side14of the cutting insert2and the fourth radial abutment face64. The fourth radial abutment face64is sandwiched from opposite sides between the second side16of the cutting insert2and the third radial abutment face63. There is a smoothly curved transition between the third and fourth radial abutment face. A smoothly curved transition is a continuously curved transition without sharp edges. The third and fourth radial abutment faces are tangentially connected to the smoothly curved transition. The third radial abutment face63is arranged and extends on the second side of the median plane MP towards the first side14. The fourth radial abutment face64is arranged and extends on the first side of the median plane MP towards the second side16.

The first pair of opposing side surfaces10,11are configured to face radially inwardly and outwardly when arranged in an insert seat of a milling tool. The second pair of opposing side surfaces12,13are configured to face in two opposite axial directions when arranged in the insert seat of the milling tool. Accordingly, each of the first pair of opposing side surfaces10,11comprises two radial relief faces and two radial abutment faces, and each of the second pair of opposing side surfaces12,13comprises two axial relief faces and two axial abutment faces.

A relationship W:L between a width W of the cutting insert2along the central plane CP and a length L of the cutting insert along the longitudinal plane LP may be within a range of 1:1.2 to 1:2. Mentioned purely as an example, e.g. W=10.76 mm and L=17.79 mm. The first and second corner cutting edges26,26′ may have a cutting insert corner radius for forming a standard corner radius in a workpiece, such as a radius of e.g. 0.8 mm, or 1.2 mm, or 1.6 mm, or any other standard or non-standard corner radius value.

A first axial relief face30is arranged adjacent to the first auxiliary cutting edge38. The first axial relief face30is indicated with hatching in a first direction inFIG.1a. Seen in a direction along the first axis A1towards the first side surface12of the second pair of opposing side surfaces12,13, the first axial relief face30and a first axial abutment face32form part of a first surface grouping34on the first side of the longitudinal plane LP. The first axial abutment face32is indicated with hatching in a second direction inFIG.1a. The first axial abutment face32is configured to abut against an axial support surface in an insert seat of a shoulder milling tool when the second cutting edge23is positioned to form an active cutting edge in the milling tool. InFIG.1athe first surface grouping34is only roughly indicated with a broken line. The first surface grouping34may comprise further surfaces, such as e.g. a transitional surface between the first axial relief face30and the first axial abutment face32.

A second axial relief face30′ is arranged adjacent to the second auxiliary cutting edge38′. The second axial relief face30′ is indicated with hatching in a first direction inFIG.1b. Seen in a direction along the first axis A1towards the first side surface12of the second pair of opposing side surfaces12,13, the second axial relief face30′ and a second axial abutment face32′ form part of a second surface grouping34′ on the first side of the longitudinal plane LP. The second axial abutment face32′ is indicated with hatching in a second direction inFIG.1b. The second axial relief face30′, the second axial abutment face32′, and the second surface grouping34′ are shown e.g. inFIG.1b. The second axial abutment face32′ is configured to abut against an axial support surface in an insert seat of a milling tool when the first cutting edge20is positioned to form an active cutting edge in the shoulder milling tool. InFIG.1bthe second surface grouping34′ is only roughly indicated with a broken line. The second surface grouping34′ may comprise further surfaces, such as e.g. a transitional surface between the second axial relief face30′ and the second axial abutment face32′.

The first surface grouping34and the second surface grouping34′ form part of the circumferential surface18. More specifically, the first grouping34forms part of the first side surface12of the second pair of opposites side surfaces12,13, and the second surface grouping34′ forms part of the second side surface13of the second pair of opposites side surfaces12,13.

The circumferential surface18is comprising four corner surfaces71,72,73,74extending between the first side14and the second side16and connecting each surface of the first pair of opposing side surface10,11to each surface of the second pair of opposing side surfaces12,13. Both the first axial relief face30and the first axial abutment face32are adjacent to a first corner surface71and preferably tangentially connected to the first corner surface71. Both the second axial relief face30′ and the second axial abutment face32′ are adjacent to a second corner surface72and preferably tangentially connected to the second corner surface72. The corner surfaces are adjacent to respective corner cutting edges—the first corner surface71is adjacent to the first corner cutting edge26and the second corner surface72is adjacent to the second corner cutting edge26′. A third corner surface73is arranged diagonally opposite to the second corner surface72, see e.g.FIGS.1aand1d. The third corner surface73is extending between and connecting the first side surface12of the second pair of opposing side surfaces12,13and the second side surface11of the first pair of opposing side surfaces10,11. A fourth corner surface74is arranged diagonally opposite to the first corner surface71, i.e. the fourth corner surface is extending between and connecting the second side surface13of the second pair of opposing side surfaces12,13and the second side surface11of the first pair of opposing side surfaces10,11. Both the first radial abutment face61and the second radial abutment face62, are adjacent to the third corner surface73and the fourth corner surface74. The first radial abutment face61and the second radial abutment face62are tangentially connected to the third corner surface73and the fourth corner surface74. The third radial abutment face63and the fourth radial abutment face64are adjacent to the first corner surface71and the second corner surface72and tangentially connected to them.

A third axial relief face30″ is arranged adjacent to the third auxiliary cutting edge38″. Seen in the direction along the first axis A1towards the second surface13of the second pair of opposing side surfaces12,13, the third axial relief face30″ and a third axial abutment face32″ form part of a third surface grouping34″ on the second side of the longitudinal plane LP. The first surface grouping34and the third surface grouping34″ meet in a partitioning line L. The partitioning line L extends from the first side14to the second side16.

The partitioning line L extends along the first side surface12of the second pair of opposing side surfaces12,13in the longitudinal plane LP and may be said to part the first side surface12in two halves. In a corresponding manner, a partitioning line extends along the second side surface13of the second pair of opposing side surfaces12,13, and may be said to part of the second side surface13in two halves.

The partitioning line L may form a distinct line, visible when looking at the cutting insert. That is, the first surface grouping34and the third surface grouping34″ may be substantially flat at the partitioning line L, and an angle difference between the first and third surface groupings34,34″ is such that the partitioning line L forms a distinct line. Alternatively, the partitioning line L may extend e.g. along a rounded ridge forming part of and extending between the first and third surface groupings34,34″.

In these embodiments, the partitioning line L is a straight line, see e.g.FIG.1e. and the partitioning line L extends perpendicularly to the median plane MP, see e.g.FIG.1f.

In these embodiments, seen in any section through the partitioning line L and in parallel with the median plane MP, the partitioning line L extends immediately adjacent to the first axial abutment face32and/or to the third axial abutment face32″. Thus, the partitioning line L is formed at an intersection between at least one of the first and third axial abutment faces32,32″. The partitioning line L extends also immediately adjacent to an end part of the first axial relief face30and an end part of the third axial relief face30″.

Seen in the view along the first axis A1the first axial abutment face32and the third axial abutment face32″ together continuously extend along the first side surface12of the second pair of opposing side surfaces12,13.

A first side surface10of the first pair of opposing side surfaces10,11comprises a first radial relief face50arranged adjacent to the first main cutting edge24, see e.g.FIGS.1a-1c. The first radial relief face50is indicated with hatching in a first direction inFIG.1a. Seen in a view along the centre axis C, i.e. in the view ofFIG.1g, at least part of the first radial relief face50extends outside of the first main cutting edge24at least along a part of the first main cutting edge24such that the first radial relief face50extends more outside the first main cutting edge24towards a second end29of the main cutting edge24than towards the first end27of the main cutting edge24. Seen in the view along the centre axis C, the first main cutting edge24may also be angled from the first end27towards the longitudinal plane LP.

In a similar manner, the first side surface10of the first pair of opposing side surfaces10,11comprises a second radial relief face50′ arranged adjacent to the second main cutting edge24′. The second radial relief face50′ is indicated with hatching in a second direction in FIG.1a. Again, seen in a view along the centre axis C, this time from the opposite direction, at least part of the second radial relief face50′ extends outside of the second main cutting edge24′ in the same manner as the first radial relief face50does in relation to the first main cutting edge24.

In a similar manner, the second side surface11of the first pair of opposing side surfaces10,11comprises a third radial relief face50″ arranged adjacent to the third main cutting edge24″, see e.g.FIG.1dandFIG.1g. The second side surface11of the first pair of opposing side surface10,11comprises also a fourth radial relief face arranged adjacent to a fourth main cutting edge. The fourth main cutting edge is a part of the fourth cutting edge23′.

The first radial abutment face61extends between the third radial relief face50″ and the second radial abutment face62. There is a smoothly curved transition between the third radial relief face50″ and the first radial abutment face61. In the same way, the second radial abutment face62extends between the fourth radial relief face and the first radial abutment face61. There is a smoothly curved transition between the fourth radial relief face and the second radial abutment face62. In the same way, the third radial abutment face63is adjacent to the first radial relief face50and extends between the first radial relief face50and the fourth radial abutment face64. The fourth radial abutment face64is adjacent to the second radial relief face50′ and extends between the second radial relief face50′ and the third radial abutment face63. There is a smooth curved transition between the first relief face50and the third radial abutment face63.

In the following, reference is made toFIGS.1cand2-2b.FIGS.2aand2bshow cross sections extending in parallel with the longitudinal plane LP along lines IIa-IIa and IIb-IIb, respectively, inFIG.2. Seen in a plane parallel with the longitudinal plane LP, such as in each of the views ofFIGS.2aand2b, the first axial relief face30extends from the first surface-wiping cutting secondary edge28at a first obtuse inner angle X to the median plane MP. In a corresponding manner, a first part31′ of the second axial relief face30′ forms a second obtuse inner angle X′ with the median plane MP when seen in a section parallel to the longitudinal plane LP, seeFIG.2d, which shows a cross section along line IId-IId inFIG.2. In this manner, a positive axial relief angle is provided in the cutting insert2at the first and second surface-wiping secondary cutting edge28,28′.

The first inner angle X and the second inner angle X′ may be within a range of 91-115 degrees, preferably within a range of 94-110 degrees, or approximately at 97 degrees. Thus, in relation to a normal of the median plane MP, a positive relief angle in a range of 1-25 degrees, preferably within a range of 4-20 degrees may be provided. The first inner angle X and the second inner angle X′ are preferably but not necessarily equal to each other along the first and second surface-wiping secondary cutting edges28,28′. The value of the first inner angle X may vary along the first surface-wiping secondary cutting edges28. The same applies to the second inner angle X′.

Seen in a plane parallel with the central plane CP, such as in the view ofFIG.2e, which shows a cross section along line IIe-IIe inFIG.2, the first radial abutment face61forms an obtuse third inner angle W to the median plane MP. When seen in the same plane, the second radial abutment face62forms an obtuse fourth inner angle W′ to the median plane. The obtuse third inner angle W and the fourth obtuse inner angle W′ may be within a range of 91-120 degrees, or within a range of 92-105 degrees or within a range of 94-100 degrees. The obtuse third inner angle W and the fourth obtuse inner angle W′ are preferably but not necessarily equal to each other along the first and second radial abutment faces61,62. The first radial abutment face61and the second radial abutment face62are preferably but not necessarily flat surfaces.

FIG.3shows a cross section of the cutting insert2ofFIGS.1a-1g. The cross section ofFIG.3extends in the plane of the median plane MP. Measured in a direction in parallel with the longitudinal plane LP, in a section of the median plane MP through the cutting insert2, i.e. in the view ofFIG.3, the cutting insert2is longest along the longitudinal plane LP. Seen in a direction along the second axis A2, i.e. perpendicularly to the longitudinal plane LP and toward the first side surface10of the first pair of opposing side surfaces10,11, as shown inFIG.1g, each point of the first and second surface groupings34,34′ has a unique projection point on the longitudinal plane LP. This means that each of the first and second surface groupings34,34′ is arranged such that each point of the first and second surface groupings34,34′ is visible in the view along the second axis A2. In a similar manner, in a view along the second axis A2in an opposite direction, each point of the third surface grouping34″, as well as a corresponding fourth surface grouping at the fourth cutting edge23′, has a unique projection point on the longitudinal plane LP. This means that the third surface grouping34″ is arranged such that each point of the third surface grouping34″ is visible in the view along the second axis A2and toward the second side surface11of the first pair of opposing side surfaces10,11. The same applies to the fourth surface grouping.

Thus, the cutting insert2is formable by MAP with a split line of a relevant pressing tool at the longitudinal plane LP. The first and second surface groupings34,34′ may be formed in the MAP operation. Being able to position a split line of a pressing tool at the longitudinal plane LP entails that the pressing tool is uncomplex and thus, easily produced. Moreover, the split line is positioned in an area where any burrs in the insert2from the MAP operation will not affect the use of the cutting insert2to any substantial extent. In particular, burrs at the longitudinal plane LP will not affect the axial position of the cutting insert2when positioned in an insert seat of a milling tool.

When manufacturing a cutting insert utilising a conventional pressing process, a powder compound is pressed between two vertical stamps into a recess of a die to form a green body, which after sintering forms a cutting insert. In MAP the powder compound in question is pressed not only between two stamps forming the first side14and the second side16of the green body to be manufactured, but also between two additional stamps, which form the circumferential surface18.

By shaping the cutting insert2in the manner described herein, i.e. seen in the direction along the second axis A2, with each point of the first surface grouping34having a unique projection point on the longitudinal plane LP, and with each point of the second surface grouping34′ having a unique projection point on the longitudinal plane LP, the two stamps forming the circumferential surface18can be retracted in a linear path of motion from the finish-pressed green body in such a way that each point on the stamp surfaces immediately clears from the green body without scraping any surface of the same. In other words, the design of the cutting insert2guarantees a good surface quality, something that in turn allows manufacture of directly pressed, non-ground cutting inserts having good dimensional accuracy. Thus, the cutting insert2may obtain its final shape directly after pressing and sintering, and without needing to be after-treated by grinding or the like. Naturally, one or more surfaces or edges of the cutting insert2may be ground after sintering to meet certain tolerances or demands of edge sharpness.

In the median plane MP an obtuse seventh inner angle ε may be formed between the first surface grouping34and the third surface grouping34″. Furthermore, in any plane parallel to the median plane MP and through both the first and third surface grouping34,34″, the obtuse seventh inner angle ε may be formed between the first and third surface grouping34,34″. The seventh inner angle ε need not be the same in each plane. Accordingly, the inner angle ε may vary between one or more of the median plane MP and the planes in parallel with the median plane.

The obtuse seventh inner angle ε may be within a range of 150-178 degrees, preferably within a range of 164-172 degrees. Mentioned purely as an example, the obtuse seventh inner angle ε may be approximately 168 degrees in the median plane MP.

With reference toFIG.3, seen in the view along the centre axis C, the first axial abutment face32forms a fifth inner angle δ with the longitudinal plane LP within a range of 75-88 degrees.

With reference toFIG.2, seen in the view along the centre axis C, the first surface-wiping secondary cutting edge28, or a tangent of the first surface-wiping secondary cutting edge extends at a sixth inner angle ϕ to the longitudinal plane LP, which sixth inner angle ϕ is ≤89 degrees, wherein the sixth inner angle ϕ is preferably larger than the fifth inner angle δ. In this manner, the first surface-wiping secondary cutting edge will extend beyond the first axial abutment face, seen in the view along the centre axis C. Thus, the cutting insert may be arranged in an insert seat of a milling tool with no, or only a small, axial rake angle of the median plane with the first surface-wiping secondary cutting edge protruding sufficiently from the first axial abutment face for cutting engagement with a workpiece. The sixth inner angle ϕ can also be equal to the fifth inner angle δ.

Referring e.g. toFIGS.1aand1b, the first axial abutment face32forms a substantially flat surface. Similarly, the second axial abutment face32′ forms a substantially flat surface. Thus, the first and second axial abutment faces32,32′ are particularly suited for abutting, one at a time, against an axial support surface in an insert seat of a milling tool. The first axial abutment face32extends perpendicularly to the median plane MP. Similarly, the second axial abutment face32′ extends perpendicularly to the median plane MP. An exact axial positioning of the cutting insert in an insert seat of a square shoulder milling tool thus, may be achieved. As discussed above, and below with reference to the milling tool, a deviation from a target thickness of the cutting insert will affect axial runout of the cutting insert at least only to a limited extent, and in some cases not at all.

Referring e.g. toFIG.3, seen in a view along the centre axis C on the first side of the longitudinal plane LP, for part of the cutting insert2which is between the median plane MP and the second side16, the first axial abutment face32forms a surface of the first surface grouping34which is the most distant surface of the cutting insert2from the centre axis C. Thus, no recesses or protrusions are provided in the first surface grouping34between the median plane MP and the second side16.

In a similar manner, seen in the view along the centre axis C on the second side surface13of the second pair of opposing side surfaces12,13, again on the first side of the longitudinal plane LP, for part of the cutting insert2between the median plane MP and the first side14, the second axial abutment face32′ forms a surface of the second surface grouping34′ which is the most distant surface of the cutting insert2from the centre axis C.

The first axial abutment face32may form a substantially flat surface extending from the median plane MP towards the second side16. The second axial abutment face32′ forms a substantially flat surface extending from the median plane MP towards the first side14.

The first axial abutment face32may form a substantially flat surface extending from the median plane MP to the second side16. The second axial abutment face32′ forms a substantially flat surface extending from the median plane MP to the first side14.

Seen in the direction along the first axis A1and projected on the central plane CP the first axial abutment face32may form at least 30% of the first surface grouping34. Similarly, seen in an opposite direction along the first axis A1and projected on the central plane CP, the second axial abutment face32′ may form at least 30% of the second surface grouping34′.

The discussion above of the different aspects of the first and second axial abutment face32,32′ may also relate to corresponding axial abutment faces on the second side of the longitudinal plane LP.

The first axial relief face30comprises a first part31of the first axial relief face30adjacent to the first surface-wiping secondary cutting edge28, seeFIG.1c.

In the following reference is made toFIGS.1cand1d, and to the cross section along line IV-IV inFIG.1eshown inFIG.4. The cross section IV-IV extends in a direction in parallel with the median plane MP. The first auxiliary cutting edge38comprise at least a second cutting edge part39. The second cutting edge part39is arranged closer to the longitudinal plane LP than the first surface-wiping secondary cutting edge28. The first axial relief face30comprises at least a second part33. The second part33is arranged adjacent to the second cutting edge part39of the first auxiliary cutting edge38, see e.g.FIG.1d. The second part33of the first axial relief face30create an obtuse tenth inner angle Z with the first part31of the first axial relief face30. In this manner, the first and second parts of the first axial relief face do not extend in one and the same plane. Thus, when the insert is mounted in the insert seat, the second cutting edge part of the first auxiliary cutting edge can be positioned furthest out in the longitudinal direction and separated from the work-piece surface created by the first surface-wiping secondary cutting edge, without a big and abrupt change of the direction of the first auxiliary cutting edge (seen in a view along the first axis) in the transition between the first surface-wiping secondary cutting edge and the second cutting edge part of the first auxiliary cutting edge. Thanks to this, during manufacturing of the cutting insert, the part of the pressing tool which creates the first side (and/or the part of the pressing tool which creates the second side) is not subject to high stress concentrations in the area of the transition between the first surface-wiping secondary cutting edge and the second cutting edge part of the first auxiliary cutting edge. The second part33of the first axial relief face30can be at least partly flat but it can be also partly curved or entirely curved surface.

In a similar manner, the second auxiliary cutting edge38′ comprises a second cutting edge part and an obtuse inner angle is created between a first part and a second part of the second axial relief face30′. The second part of the second axial relief face30′ can be at least partly flat but it can be also partly curved or entirely curved surface.

In the following reference is made toFIGS.2-2c.FIGS.2a-2cshow cross sections extending in parallel with the longitudinal plane LP along lines a-a, b-b, and c-c, respectively, inFIG.2.

When seen in different sections in parallel with the longitudinal plane LP, such as exemplified by the cross sections ofFIGS.2a-2c, and through the first auxiliary cutting edge38, the first axial relief face30forms an eleventh inner angle Y in relation to the median plane MP. The eleventh inner angle Y is measured adjacent to the first auxiliary cutting edge38. The eleventh inner angle Y differs for at least some of the different sections in parallel with the longitudinal plane LP. This applies also for the corresponding inner angle measured adjacent to the second auxiliary cutting edge38′.

The eleventh inner angle Y, at an end of the first axial relief face30close to the longitudinal plane LP, may be equal to or substantially equal to an inner angle of the partitioning line L to the median plane MP. Thus, in embodiments wherein the partitioning line L extends perpendicularly to the median plane MP, the eleventh inner angle Y will transition from an obtuse inner angle farther way from the longitudinal plane LP to a perpendicular inner angle, or substantially perpendicular inner angle, close to the longitudinal plane LP. This applies also for the corresponding inner angle measured adjacent to the second auxiliary cutting edge38′.

Along the first surface-wiping secondary cutting edge28of the first auxiliary cutting edge38the first inner angle X and the eleventh inner angle Y coincide with each other. This applies also for and along the second surface-wiping secondary cutting edge28′.

With reference toFIGS.1cand1e, seen in the view along the first axis A1towards the first side surface12of the second pair of opposing side surfaces12,13, at least part of the first axial abutment face32is arranged between the second side16and at least a part of the first surface-wiping secondary cutting edge28or at least a major part of the surface-wiping secondary cutting edge28. In the same way, at least a part of the second axial abutment face32′ is arranged between the first side14and at least a part of the second surface-wiping secondary cutting edge28′ or at least a major part of the second surface-wiping secondary cutting edge28′. When the first axial abutment face32abuts against an axial support surface in an insert seat of a milling tool, the second cutting edge23, and its second surface-wiping secondary cutting edge28′ is active, i.e. arranged for cutting engagement with a workpiece. With the above-mentioned arrangement of the first axial abutment face32in relation to the first surface-wiping secondary cutting edge28, an axial support of the cutting insert2is provided along an axial direction from the second surface-wiping secondary cutting edge28′. Thus, a low error axial error positioning of the cutting insert in the insert seat of the milling tool may be provided.

Seen in the view along the first axis A1towards the first side surface12of the second pair of opposing side surfaces12,13, the first axial relief face30has a height h in a direction parallel with the longitudinal plane LP and projected on the central plane CP, seeFIG.1e. The height h increases in a direction away from the longitudinal plane LP towards the first corner cutting edge26. In this manner, the first axial relief face30has its largest height h in the vicinity of the first corner cutting edge26, where normally the risk of fractures is the largest due to high loads at the corner cutting edge. The large height h towards the corner cutting edge26means stress concentration in a transition from the axial relief face30to the axial support surface32is formed at a distance from the corner cutting edge26. At the same time, the smaller height h towards the longitudinal plane makes it easier to obtain a simplified partitioning line L which in its turn simplifies the pressing tool.

Seen in the view along the first axis A1towards the first side surface12of the second pair of opposing side surfaces12,13, the first axial relief face30is adjacent to the first corner surface71and preferably tangentially connected to the first corner surface71, seeFIG.1a. Also, the third axial relief face30″ is adjacent to the third corner surface73and preferably tangentially connected to the third corner surface73. The first axial relief face30is arranged such that a distance from the median plane MP to the first axial relief face increases in a direction away from the first corner face71toward the longitudinal plane LP. Thanks to this, the first axial abutment face32can be enlarged which gives possibility to improved stability of the insert but which also simplifies the area around the partitioning line L where the first surface grouping34meets the third surface grouping34″ which in its turn contributes to improved tolerances of the insert. Also, the third axial relief face30″ is arranged such that a distance from the median plane MP to the third axial relief face increases in a direction away from the third corner surface73toward the longitudinal plane. Thanks to this, the third axial abutment face32″ can be enlarged which gives possibility to improved stability of the insert but which also simplifies the area around the partitioning line L where the first surface grouping34meets the third surface grouping34″ which in its turn contributes to improved tolerances of the insert. In the same manner, the second axial relief face30′, seeFIG.1b, is arranged such that a distance from the median plane MP to the second axial relief face30′ increases in a direction away from the adjacent second corner face72toward the longitudinal plane.

The first and second radial relief face50,50′ are adjacent to the first and second corner surface71,72and preferably tangentially connected to the first and second corner surface71,72, seeFIG.1a.

With reference toFIG.1e, seen in the view along the first axis A1, the first surface-wiping secondary cutting edge28, or a tangent to the first surface-wiping secondary cutting edge in the midpoint of the first surface-wiping secondary cutting edge, extends at a twelfth sharp angle A to the median plane MP, such that a first end of the first surface-wiping secondary cutting edge28adjacent to the first corner cutting edge26is situated at a greater distance from the median plane MP than the opposite end of the first surface-wiping secondary cutting edge28adjacent to the second cutting edge part39of the first auxiliary cutting edge38. The twelfth angle A is greater than 0 degrees, or preferably 15°≤λ≤25°.

FIGS.5aand5billustrate side views of the cutting insert2according to a second embodiment.FIGS.5aand5bare views towards the second side surface11and the first side surface10respectively of the first pair of opposing side surfaces10,11. The second embodiment of the cutting insert differs from the above described embodiments in that the first radial abutment face61′ is arranged on both sides of the median plane MP and in that the second radial abutment face62′ is arranged on both sides of the median plane MP, seeFIG.5a. The second embodiment of the cutting insert differs also from the above described embodiments in that the third radial abutment face63′ is arranged on both sides of the median plane MP and in that the fourth radial abutment face64′ is arranged on both sides of the median plane MP. All other features of the cutting insert according to the second embodiment may be the same as the features of the cutting insert according to the first embodiment and/or the features of the cutting insert according to the earlier described embodiments.

FIGS.6a-6dillustrate different views of a milling tool40according to embodiments. The milling tool40is a square shoulder milling tool. The milling tool40is configured to be rotated about a rotation axis42. The milling tool comprises a tool body44. The tool body44at a first axial end portion45thereof is provided with an insert seat46for receiving a cutting insert2. In these embodiments the tool body44is provided with six insert seats46. According to alternative embodiments, inter alia depending on a diameter of the tool body, the tool body may be provided with less or more than six insert seats. A smaller diameter tool body may for instance be provided with two insert seats. Whereas a larger diameter tool body may be provided with ten, twelve, or more insert seats. At a second axial end portion, opposite to the first axial end portion45, the tool body44is configured for mounting the tool body44to e.g. a rotating spindle of a machine via e.g. a tool holder (not shown).

The milling tool40is configured to comprises a cutting insert2according to any one of aspects and/or embodiments discussed herein arranged in each of the insert seats46. For the sake of clarity, cutting inserts have been omitted in some of the insert seats46inFIGS.6aand6b. In these embodiments, the cutting insert2is secured to the tool body44with a screw47extending through the through hole9of the cutting insert2and co-operating with a threaded hole in the insert seat.

Each of the insert seats46is provided with a tangential support surface52, a first radial support surface54, and an axial support surface56. The axial support surface56extends perpendicularly or substantially perpendicularly to the tangential support surface52. Each of the insert seats46may optionally be provided with a second radial support surface54′.

When positioned in the insert seat46, the cutting insert2and the insert seat46are arranged such that a portion of the first or second side14,16of the cutting insert2is abutting against the tangential support surface52, a portion of the first or second side surface10,11of the first pair of opposing side surfaces10,11abutting against the first radial support surface54, and a portion of the first or second side surface12,13of the second pair of opposing side surfaces12,13is abutting against the axial support surface56.

When the first cutting edge20is positioned for cutting engagement with a workpiece in the insert seat46, as indicated inFIG.6a, the second side16abuts against the tangential support52, the first radial abutment face61abuts against the first radial support surface54, and the second axial abutment face32′ at the second side surface13of the second pair of opposing side surfaces12,13abuts against the axial support surface56in the insert seat46. The axial support surface56need not abut against the entire second axial abutment face32′ of the cutting insert2.

The axial support surface56extends in a first support plane S1. The first support plane S1crosses the rotation axis42on a side of the insert seat46opposite to the first axial end portion45. Thus, the axial support surface56leans towards the first axial end portion45towards a radially outer portion of the insert seat46. This entails that an axial force applied to the cutting insert2during a milling operation provides a radial force component at the axial support surface56pushing the cutting insert2radially inwardly into the insert seat46.

As discussed above, the arrangement of e.g. the first axial abutment face32at the first side surface12of the second pair of opposing side surfaces12,13between the second side16and at least a part of the first surface-wiping secondary cutting edge28provides for an axial support of the cutting insert2along an axial direction from the second surface-wiping secondary cutting edge28′ to the axial support surface56(when the second cutting edge23is positioned for cutting engagement with a workpiece). The axial support is provided far outwardly in a radial direction due to the axial abutment face32being provided axial opposite to the surface-wiping secondary cutting edge. Thus, a stable positioning of the cutting insert2in the insert seat may be provided.

The first radial support surface54extends in a second support plane S2, wherein the second support plane S2crosses the rotation axis42on a same side of the insert seat46as the first axial end portion45. Thus, the first radial support surface54leans towards the rotation axis42at an axially outer end of the insert seat46.

Namely, as discussed above, seen in the view along the centre axis C, at least part of the first radial relief face50extends outside of the first main cutting edge24at least along a part of the first main cutting edge24, preferably such that the first radial relief face50extends more outside the first main cutting edge24towards a second end29of the main cutting edge24than towards the first end27of the main cutting edge24. Thus, the first main cutting edge24of the cutting insert2is positioned to extend on the wall of an imaginary cylinder or substantially on the wall of that cylinder having same centre axis as the rotation axis42of the milling tool40.

The insert seat46is configured to provide an axial rake angle γp for the median plane MP of the cutting insert2arranged in the insert seat46, seeFIG.6c. The insert seat46is configured to provide an axial rake angle γp equal to 0 degrees or a negative axial rake angle γp having an absolute value within a range of 0<|γp|≤3 degrees, or within a range of 0.5≤|γp|≤2 degrees, or of approximately 1 degree.

Thus, the cutting insert2is only marginally tilted in an axial direction of the milling tool40. Thus, a deviation from a target thickness of the cutting insert2, i.e. in a direction along the centre axis C of the cutting insert2, will not affect axial runout of the cutting insert2, or at least will affect axial throw/runout only to a limited extent.

The insert seat46is configured to provide a negative radial rake angle γf for the median plane MP of the cutting insert2arranged in the insert seat46, seeFIG.6d. The insert seat46is configured to provide a negative radial rake angle γf having an absolute value within a range of 10≤|γf|≤30 degrees, or within a range of 15≤|γf|≤25 degrees. In this manner, a functional positive relief angle of the main cutting edge of the first cutting edge20may be formed by the radial rake angle γf.

Namely, as discussed above, seen in the view along the centre axis C, at least part of the first radial relief face50extends outside of the first main cutting edge24at least along a part of the first main cutting edge. Thus, the radial rake angle γf provides for a positive functional rake angle when the cutting insert2is positioned in the insert seat46.

FIG.6eshows a cross section along line VIe-VIe inFIG.6c, through the insert seat46and in parallel with the central plane CP of the cutting insert2, when the cutting insert2is mounted in the insert seat46. For simplicity reasons, the cutting insert is omitted inFIG.6e. The first radial support surface54extends at a sharp eight angle μ1 to the tangential support surface52, as indicated inFIG.6e. The sum of the sharp eight angle μ1 and the obtuse third inner angle W is in the range of 179-181 degrees, or within the range of 179.5-180.5 degrees or 180 degrees.

The insert seat46may be arranged with the second radial support surface54′. The second radial support surface54′ may extend at an obtuse ninth angle to the tangential support surface52, when seen in a section through the insert seat46and in parallel with the central plane CP when the cutting insert2is mounted in the insert seat46, as indicated inFIG.6e. The obtuse ninth angle μ2 may be such that an absolute value of a difference between the obtuse ninth angle μ2 and the obtuse fourth inner angle W′, is |μ2−W′|≤1°, or |μ2−W′|≤0.5°, or |μ2−W′|=0°. The insert seat46and the cutting insert2may be arranged such that the second radial abutment face62abuts against the second radial support surface54′ at the same time as the first radial abutment face61abuts against the first radial support surface54, when the first cutting edge20is in operable position.

The milling tool40illustrated inFIGS.6a-6e, has the first radial support surface54arranged only on one side of the median plane MP, when the cutting insert is mounted in the insert seat.

When the cutting insert2is mounted in the insert seat of the milling tool40illustrated inFIGS.6a-6e, the first radial support surface54extends only on one side of the median plane MP, namely between the median plane MP and the tangential support surface52. Thus, the insert seat46is adapted for reception of the cutting insert illustrated inFIGS.1-4. However, the cutting insert illustrated inFIGS.5aand5bmay also be mounted in the insert seat46of the milling tool40illustrated inFIGS.6a-6e.

In a further one embodiment of the milling tool (not shown in the drawings), the insert seat may be arranged with a first radial support surface that extends on both sides of the median plane MP, when the cutting insert illustrated inFIGS.5aand5bis mounted in the insert seat. The first radial support surface is furthermore arranged such that the first radial abutment face61′ abuts the first radial support surface on both sides of the median plane MP when the cutting insert illustrated inFIGS.5aand5bis mounted in the insert seat and the first cutting edge20is in operable position. Such an insert seat may also be arranged with a second radial support surface arranged such that the second radial abutment face62′ abuts the second radial support surface at the same time as the first radial abutment face61′ abuts the first radial support surface when the cutting insert illustrated inFIGS.5aand5bis mounted in the insert seat and the first cutting edge is in operable position. The second radial support surface may also be arranged such that it extends on both sides of the median plane MP and such that the second radial abutment face62′ abuts the second radial support surface on both sides of the median plane MP when the cutting insert illustrated inFIGS.5aand5bis mounted in the insert seat and the first cutting edge20is in operable position. This milling tool and this insert seat may have all other mentioned features of the milling tool40and the insert seat46illustrated inFIGS.6a-6e.

It is to be understood that the foregoing is illustrative of various example embodiments and that the invention is defined only by the appended claims. A person skilled in the art will realize that the example embodiments may be modified, and that different features of the example embodiments may be combined to create embodiments other than those described herein, without departing from the scope of the invention, as defined by the appended claims.

The invention is not limited to a square shoulder milling insert and a square shoulder tool, and it can be applied also on other types of double-sided inserts and other types of milling tools, such as high-feed cutting inserts and high-feed milling tools. However, the invention is especially beneficial when applied to square shoulder inserts and tools because of requirements related to surface quality of the machined surface and 90° wall.