Metal cutting and milling tools

Abstract

A metal cutting milling tool 100 comprising a body rotatable in a rotational direction about a central axis C, the body comprising a front end 106, a plurality of lands 156 extending axially rearward from the front end 106, and a plurality of chip looms 146 extending axially rearward from the front end, each land 156 of the plurality of lands being bounded in the rotational direction by a front face 157 and a rear face 158, the front face 157 being rotationally forward of the rear face 158, each land 156 as a portion of the front face 157 in a radially outer forward region comprises an insert seat 110 for receiving a cutting insert 114, each chip loom 146 of the plurality of chip looms being bounded by a front face 157 and a rear face 158, the front face 157 being rotationally forward of the rear face 158, 1. A metal cutting milling tool, comprising: a first land portion; a third land portion; a third cross section; and a third cross section. 2. The metal cutting milling tool of claim 1, wherein the first land portion is rotationally forward of the second land portion; and wherein the first cross section is axially forward of the second cross section. 3. The metal cutting milling tool of claim 1, wherein the first cross section is axially forward of the second cross section and the third cross section.

Description

Technical Field

[0001] The present invention relates to a metal cutting milling tool for chip-removing machining of the type comprising a base body rotatable in a predetermined direction about a central axis and having a front end face and an outer circumferential surface extending axially rearward from the front end face. The milling tool further comprises insert seats spaced apart circumferentially, the insert seats being configured to receive cutting inserts each having a cutting edge that removes material from a workpiece. Background Art

[0002] Metal cutting milling tools are provided with chip spaces for accommodating cutting inserts and for moving milled chips away from a machined surface. Compromises are always required when designing the chip spaces of a milling tool. The cutting insert should preferably fit into the chip space, and sufficient space is also required to move the milled chips away from the machined surface. However, a design that takes the above matters into consideration has problems regarding the strength of other portions of the milling tool.

[0003] Accordingly, there is a need for an improved metal cutting milling tool that increases the strength of the milling tool while having chip spaces sufficiently large to accommodate cutting inserts. Summary of the Invention

[0004] Accordingly, it is an object of the present invention to provide an improved metal cutting milling tool that alleviates some of the problems described above.

[0005] According to the present invention, the above object is achieved by a metal cutting milling tool having the features defined in claim 1.

[0006] The metal cutting milling tool according to the present invention comprises a body that is rotatable in the rotational direction about a central axis, the body comprising a front end, a plurality of lands extending axially rearward from the front end, and a plurality of chip rooms extending axially rearward from the front end. Each of the plurality of lands is bounded in the rotational direction by a front and a rear surface, the front surface being in the rotational forward direction of the rear surface, and each land as part of the front surface in the radially outward front region comprises an insert sheet for receiving a cutting insert. Each of the plurality of chip rooms is located between two adjacent lands of the plurality of lands, and each chip room is bounded by a chip room surface including the rear surface of a first land, the front surface of a second land, and a bottom surface located between the rear and front surfaces. The first land is in the rotational forward direction of the second land, and viewed in a cross section perpendicular to the central axis, each chip room surface has a curvature with a minimum radius. The minimum radius of the second cross section and the minimum radius of the third cross section are greater than the minimum radius of the first cross section, and the first cross section is located axially forward of the second and third cross sections.

[0007] The inventors realized that this configuration mitigates the problem of increasing the strength of a milling tool while having a chip room large enough to accommodate the cutting insert. The relatively small radius of the first cross section allows for a deep chip room, where the cutting insert is typically located, closest to the front end of the milling tool, without removing an excessive amount of material from the tool. This is because the relatively small radius narrows the chip room, allowing the cutting insert to be fitted into the chip room. Removing a large amount of material from the milling tool reduces its strength. The relatively large radii of the second and third cross sections allow for a shallower chip room further away from the front end of the milling tool compared to the first cross section. Having a shallower chip room with a larger radius in this area means that less material is removed from the milling tool in the cross section where strength is most critical. Larger radii also provide greater resistance to cracking than smaller radii. This combination, with a relatively small radius in the first cross-section and larger radii in the second and third cross-sections, increases the strength of the milling tool while providing a chip room large enough to accommodate the cutting insert.

[0008] The bottom surface of the chip chamber is a portion of each cross section perpendicular to the central axis, where the rear and front surfaces meet. The curvature with the minimum radius of each chip chamber surface in each cross section is found at the bottom surface of the chip chamber. Preferably, the bottom surface is also the portion of each cross section closest to the central axis of the milling tool.

[0009] The insert sheet, more specifically, refers to the bottom of the insert sheet, i.e., the surface of the insert sheet that contacts the underside of the cutting insert. The underside of the cutting insert is defined as the surface opposite to the top side of the cutting insert, which has a rake surface. The insert sheet is not necessarily a single flat surface, but is defined as the area enclosed by points on the bottom of the insert sheet that contact the cutting insert, which has a flat underside. Thus, the insert sheet may be, for example, concave, and only the outer points of the insert sheet contact the cutting insert.

[0010] Axial forward refers to being closer to the front end of the milling tool.

[0011] According to one embodiment, the first cross section is located axially along the axial length of the insert sheet, and the second and third cross sections are located axially further from the front end than the axial length of the insert sheet.

[0012] This configuration ensures that the radius is relatively small in the axial position where the insert sheet is located and relatively large in the axial position away from the front end of the milling tool. This allows for a milling tool optimized for strength while having a chip room at the front end with sufficient depth to accommodate the cutting insert.

[0013] The axial length of an insert sheet refers to the axial distance along which the insert sheet has an extended portion.

[0014] According to one embodiment, the minimum radius of the third cross-section is greater than the minimum radius of the second cross-section.

[0015] According to one embodiment, the minimum radius is, strictly speaking, increasing between the minimum radius of the second cross-section and the minimum radius of the third cross-section.

[0016] According to one embodiment, the minimum radius increases linearly between the minimum radius of the second cross-section and the minimum radius of the third cross-section.

[0017] This configuration results in a greater strength for the milling tool because the minimum radius increases as you move away from the front end of the tool. This increases the strength of the milling tool, and the smooth increase in radius ensures that no crack initiation points occur.

[0018] According to one embodiment, the minimum radius is substantially constant in all cross-sections along the axial length of the insert sheet.

[0019] This configuration ensures an optimal radius in the first cross-section. This is because this radius should be optimally set to achieve a chip room deep enough to accommodate the cutting insert.

[0020] According to one embodiment, the minimum radius of the third cross-section is 2 to 4 times the minimum radius of the first cross-section.

[0021] According to one embodiment, the minimum radius of the third cross-section is 2 to 10 mm.

[0022] The minimum radius of the third cross-section is more preferably 3 to 8 mm.

[0023] This configuration ensures that the chip room is large enough to accommodate a standard cutting insert, but not so large that an excessive amount of material is removed from the milling tool. The specific ratio of the minimum radius of the third cross section to the minimum radius of the first cross section ensures that the radius does not change so quickly as to cause a crack initiation point, but changes sufficiently along the axial length of the chip room to achieve optimal strength for the milling tool.

[0024] According to one embodiment, the depth of the chip room in the third cross-section is smaller than the depth of the chip room in the first cross-section.

[0025] The depth is defined, in each cross-section, as the shortest distance from the bottom surface of the chip room to the virtual circumferentially extending portion of the peripheral surface of the milling tool, that is, the arc obtained when two adjacent land portions are connected by a virtual arc.

[0026] The radial distance from the central axis of the milling tool to the bottom surface is greater in the third cross-section than in the first cross-section.

[0027] This configuration ensures that the chip room does not have unnecessary depth in cross-sections spaced apart from the front end of the milling tool. The smaller the depth of the chip room, the higher the strength of the milling tool.

[0028] According to one embodiment, the bottom surface of the chip room in all cross-sections between the second cross-section and the third cross-section has an arc shape in a cross-section substantially parallel to the length direction of the chip room.

[0029] The length direction of the chip room is the direction of a line passing through the minimum radius of the second cross-section and the minimum radius of the third cross-section.

[0030] This configuration enables a smooth transition from the chip room having a relatively large depth near the front end of the milling tool to the chip room having a relatively small depth axially spaced apart from the front end of the milling tool. This smooth transition minimizes the risk of crack initiation sites.

[0031] According to one embodiment, in the second cross-section, the chip room extends in the circumferential direction to a position disposed in the virtual axially extending portion of the insert seat.

[0032] This configuration ensures that there is sufficient chip room space immediately axially adjacent to the insert seat, and thus implicitly also in the axially extending portion of the cutting insert. A sufficiently large chip room is required to effectively remove chips from the surface to be cut.

[0033] The virtual axial extension portion refers to the area that occupies the same circumferential position as the insert sheet, and is located axially further from the front end than the insert sheet.

[0034] Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. [Brief explanation of the drawing]

[0035] [Figure 1] This is a side view of a metal cutting milling tool according to an embodiment of the present invention. [Figure 2] This is another side view of the metal cutting milling tool shown in Figure 1, with the cutting insert attached to the milling tool. [Figure 3] Figure 2 shows an end view of a metal cutting milling tool, specifically the front end of the milling tool. [Figure 4a-4c] Figure 1 is a cross-sectional view of a metal cutting milling tool. [Figure 5] Figure 1 is a cross-sectional view of a metal cutting milling tool. [Modes for carrying out the invention]

[0036] The following definitions are valid for all embodiments.

[0037] The sheet pitch angle α is defined as the angle between the radius at which the first land portion intersects the radially outer point of the insert sheet and the radius at which the second land portion intersects the corresponding point of the insert sheet, and the first land portion and the second land portion are adjacent and continuous land portions in the rotational direction.

[0038] Arc length AL is defined as the circumferential distance along the radial circumference of the milling tool at the front end of the milling tool, for each land portion, between the insert sheet and the rear surface of each land portion.

[0039] The pitch angle β is defined as the angle between a line parallel to the top of the first cutting insert and a similar line parallel to the top of the second insert, in a plane perpendicular to the central axis C at the front end of the milling tool, where the second insert is an adjacent, continuous insert in the rotational direction of the milling tool.

[0040] The opening angle γ of each cutting insert is defined at the front end of the milling tool, in a plane perpendicular to the central axis C, as the angle between a line parallel to the upper side of the cutting insert and a line parallel to the rear surface of the adjacent land portion, which is associated with the same chip room as the cutting insert.

[0041] The following describes embodiments of the present invention, as shown in Figures 1 and 2. The figures show a metal cutting milling tool, represented as 100 in its entirety. The metal cutting milling tool 100 has a rear end 104 for mounting on a rotatable tool holder (not shown), a front end 106, and an outer circumferential surface 108. In this embodiment, the outer circumferential surface 108 is generally cylindrical in the region closest to the front end 106 and generally conical in the region adjacent to the cylindrical region.

[0042] A milling tool defines a central axis C, which is also the longitudinal axis around which the milling tool rotates in the rotational direction R. In the following description, a direction described as extending axially is substantially parallel to the central axis C, and a direction described as extending radially is substantially perpendicular to the central axis C.

[0043] The metal cutting tool 100 further comprises tangentially spaced chip chambers 146 for transferring milled chips from the machining work surface. Land portions 156 are positioned between each chip chamber 146. The land portions 156 function as wings extending radially from the central axis C. The land portions 156 form the radial outer circumference of the milling tool 100. In the illustrated embodiment, the outer circumference of the land portions 156 extends axially at the points closest to the front end 106 and further to the rear end 104, and the outer circumference of the land portions 156 approaches the central axis C.

[0044] Each land portion 156 is bounded in the rotational direction R by a front surface 157 and a rear surface 158. The front surface 157 is in the rotational forward direction of the rear surface 158. Each front surface 157 forms a portion of the interface of the corresponding chip room 146 and a portion of the interface of the corresponding land portion 156. Here, "corresponding" means that a feature labeled "a" in the figure is associated with other features labeled "a", a feature labeled "b" is associated with other features labeled "b", and so on. Each rear surface 158 forms a portion of the interface of the chip room 146, rear surface 158b forms a portion of the interface of chip room 146a, rear surface 158c forms a portion of the interface of chip room 146b, and so on. Furthermore, each rear surface 158 forms a portion of the interface of the corresponding land portion 156.

[0045] Each front surface 157 has an insert seat 110 for a removablely mounted cutting insert 114. In this embodiment, all cutting inserts 114 are located at the front end 106 of the milling tool 100. When the milling tool 100 is used for face milling, each cutting insert 114 has at least one cutting edge extending radially. When the milling tool 100 is used for right-angle end-face milling, each cutting insert has at least one cutting edge extending radially and one cutting edge extending axially. In this specification, face milling and right-angle end-face milling are collectively referred to as end milling.

[0046] In this embodiment, the cutting insert 114 is attached by tightening a screw located through a threaded hole 112 of the milling tool 100 into a through-hole in the cutting insert. In the illustrated embodiment, each threaded hole 112 extends across the corresponding insert sheet 110, and each threaded hole 112 is a through-hole. Each through-threaded hole 112 can be said to start from the insert sheet 110 and end on either the radially outer surface of the land portion 156, the rear surface 158, or partially on the land portion 156 and partially on the rear surface 158. As will be described in detail later, all threaded holes 112 have substantially equal lengths and end at substantially the same position relative to the corresponding cutting insert 114; that is, the ends of the threaded holes 112 are in substantially the same axial position from the main front end 106 and are at substantially the same tangential distance from their respective insert sheet 110 for each threaded hole 112. According to the illustrated embodiment, the longest threaded hole is up to 10% longer than the shortest threaded hole. The longest threaded hole is more preferably up to 5% longer than the shortest threaded hole. In the illustrated embodiment, all threaded holes 112 extend at the same angle to their respective insert sheets 110. Forming the threaded holes 112 as through holes simplifies the manufacture of the milling tool 100 and allows for longer threads, as threading can be performed from both sides of the hole. Having longer threads allows for a cutting insert 114 that is more firmly and stably mounted by the insert sheet 110. The through-hole configuration also simplifies the replacement of the cutting insert 114, as the thread can be pushed from behind if it becomes stuck in the hole. The advantage of the feature that all threaded holes 112 are approximately equal in length and end at approximately the same relative position is that manufacturing is greatly simplified. This is because drilling and threading of the holes can be done with the same tool for all threaded holes 112, and since all threaded holes 112 end at approximately the same relative position, this process is usually performed by an automated robot, making the positioning of the robot arm easier.

[0047] Next, refer to Figure 3, which is an end view of the milling tool 100 shown in Figures 1 and 2. The sheet pitch angle α is defined as the angle between the radius at which the first land portion 156 intersects the radially outer point of the insert sheet 110 and the radius at which the second land portion 156 intersects the corresponding point, where the first land portion and the second land portion are adjacent, continuous land portions in the rotational direction.

[0048] At least three of the sheet pitch angles α are different, i.e., at least three sheet pitch angles α are not equal. It is more preferable that four of the sheet pitch angles α are different, and most preferable that all of the sheet pitch angles α are different. The maximum sheet pitch angle α is preferably at least 5° greater than the minimum sheet pitch angle. It is more preferable that the maximum sheet pitch angle α is at least 8° greater than the minimum sheet pitch angle. This configuration allows for a milling tool 100 having a differential pitch between the cutting inserts 114, i.e., the engagement frequency of the cutting inserts changes as the milling tool rotates and machines the workpiece. This reduces the risk of self-excited oscillation of the milling tool 100, thereby reducing vibration. The greater the number of different sheet pitch angles α and the greater the difference between the maximum and minimum sheet pitch angles, the better the tendency to reduce vibration.

[0049] The arc length AL is defined as the circumferential distance along the radial circumference of the milling cutter between the insert sheet 110 and the rear surface 158 of each land portion 156 at the front end 106 of the milling tool 100. The longest arc length AL is up to 10% longer than the shortest arc length AL. Preferably, the longest arc length AL is up to 5% longer than the shortest arc length AL. This configuration improves the balance of the milling tool 100, and the individual land portions 156 have more uniform strength compared to known milling tools with differential pitch. The amount of material behind all insert sheets 110 is more uniform compared to known milling tools with differential pitch. This material is located furthest from the central axis C of the milling tool 100 and therefore significantly affects the balance of the milling tool 100. Furthermore, to ensure sufficient strength of all land portions 156, the shortest arc length AL is preferably at least the same length as the thickness of the cutting insert 114. The thickness of the cutting insert 114 is defined as the distance between the upper and lower sides of the cutting insert.

[0050] The pitch angle β is defined as the angle between a line parallel to the top of the first cutting insert 114 and a similar line parallel to the top of the second insert, in a plane perpendicular to the central axis C at the front end of the milling tool, where the second insert is an adjacent, continuous insert in the rotational direction of the milling tool 100. By using cutting inserts 114 that are all identical to one another, the pitch angle β becomes equal to the corresponding sheet pitch angle α. This is a significant advantage because the sheet pitch angle α is optimized with respect to differential pitch and vibration reduction. Making all cutting inserts 114 identical also simplifies the handling of inserts when replacing them, as there is no risk of mixing up different types of cutting inserts.

[0051] It is preferable that all cutting inserts 114 are positioned at the same radial distance from the central axis C. The advantage of this is that all cutting inserts 114 operate during milling, regardless of the feed rate and feed rate used.

[0052] The opening angle γ of each cutting insert 114 is defined as the angle between a line parallel to the upper side of the cutting insert 114 and a line parallel to the rear surface 158 of the adjacent land portion 156, which is associated with the same chip room 146 as the cutting insert 114, in a plane perpendicular to the central axis C at the front end 106 of the milling tool. At least three, preferably all, of the opening angles γ are different. Furthermore, the range of the opening angles γ is 60 to 100°. This configuration further enhances the ability of the milling tool 100 to reduce vibration.

[0053] Figure 4 is a cross-sectional view of the milling tool 100 shown in Figure 1. Each chip room 146 is bounded by a chip room surface that includes the rear surface 158 of the first land portion 156, the front surface 157 of the second land portion 156, and the bottom surface located between the rear surface 158 and the front surface 157. Here, the first land portion 156 is in the rotational forward direction of the second land portion. The minimum radius r of curvature of each chip room 146 is shown in three different cross-sections at various distances from the front end portion 106 of the milling tool 100. The cross-sections are perpendicular to the central axis C. The minimum radius r2 of the second cross-section and the minimum radius r3 of the third cross-section are greater than the minimum radius r1 of the first cross-section. The first cross-section is axially forward of the second and third cross-sections.

[0054] This configuration mitigates the problem of increasing the strength of the milling tool while having a chip room 146 large enough to accommodate the cutting insert 114. The relatively small radius r1 of the first cross section allows for a deep chip room 146, where the cutting insert 114 is normally located, closest to the front end 106 of the milling tool 100, without removing an excessive amount of material from the milling tool. This is because the relatively small radius r1 narrows the chip room 146. This allows the cutting insert 114 to be fitted into the chip room 146. Removing a large amount of material from the milling tool 100 reduces the strength of the milling tool. Having relatively large radii r2, r3 in the second and third cross sections allows for a shallower chip room 146 further away from the front end 106 of the milling tool compared to the first cross section. Having a shallower chip room 146 with a larger radius in this location means that less material is removed from the milling tool in the cross section where strength is most critical. The larger the radius, the greater the resistance to crack formation compared to a smaller radius. As a result, a combination having a relatively small radius r1 in the first cross section and larger radii r2 and r3 in the second and third cross sections increases the strength of the milling tool while having a chip room 146 large enough to accommodate the cutting insert 114.

[0055] The bottom surface of the chip room 146 is a portion of each cross section perpendicular to the central axis C, where the rear surface 158 and the front surface 157 meet. The curvature with the minimum radius r of each chip room surface in each cross section is found at the bottom surface of the chip room 146. Preferably, the bottom surface is also the portion of each cross section closest to the central axis C of the milling tool 100.

[0056] The first cross section is preferably located axially along the axial length of the insert sheet 110, while the second and third cross sections are preferably located axially further from the front end 106 than the axial length of the insert sheet 110. The minimum radius r3 of the third cross section is preferably larger than the minimum radius r2 of the second cross section. This makes it preferable that the radii have the relationship r3 > r2 > r1. This makes it preferable that the minimum radii r1, r2, and r3 of the curvature of the chip room 146 increase as they approach the rear end 104 of the milling tool 100. The minimum radius r is preferably increasing strictly between the minimum radius r2 of the second cross section and the minimum radius r3 of the third cross section. It is more preferable that the minimum radius r increases linearly between the minimum radius r2 of the second cross section and the minimum radius r3 of the third cross section.

[0057] The axial length of the insert sheet 110 refers to the axial distance along which the insert sheet 110 has an extended portion.

[0058] In one embodiment, the minimum radius r1 of the first cross-section is substantially constant along the entire axial length of the insert sheet 110. The minimum radius r3 of the third cross-section is preferably 2 to 10 mm. More preferably, the minimum radius r3 of the third cross-section is 2 to 4 times the minimum radius r1 of the first cross-section.

[0059] As shown in Figure 5, the depth of the chip room 146 in the third cross-section is smaller than the depth of the chip room in the first cross-section.

[0060] The depth is defined in each cross-section as the shortest distance from the bottom surface of the chip room to the virtual circumferential extension of the outer surface 108 of the milling tool 100, i.e., the arc obtained when two adjacent land portions 156 are connected by a virtual arc.

[0061] This configuration ensures that the chip room does not have unnecessary depth in the cross-section away from the front end of the milling tool. The smaller the depth of the chip room, the greater the strength of the milling tool.

[0062] The radial distance from the central axis C of the milling tool 100 to the bottom surface is greater in the third cross-section compared to the first cross-section.

[0063] Preferably, the bottom surface of the chip room 146 in all cross-sections between the second and third cross-sections has the shape of an arc r4 in a cross-section substantially parallel to the longitudinal direction of the chip room 146.

[0064] The longitudinal direction of the chip room 146 is the direction of the line passing through the minimum radius r2 of the second cross section and the minimum radius r3 of the third cross section.

[0065] This configuration allows for a smooth transition from a chip room 146 with a relatively large depth near the front end 106 of the milling tool 100 to a chip room with a relatively small depth located axially away from the front end of the milling tool 100. This smooth transition minimizes the risk of crack initiation.

[0066] As shown in Figure 1, it is preferable that the chip room 146 extends in the circumferential direction to the portion of the insert sheet 110 that is positioned in the virtual axial extension.

[0067] The virtual axial extension portion refers to the part that occupies the same circumferential position as the insert sheet 110, and is located axially further away from the front end 106 than the insert sheet 110.

[0068] This configuration ensures that there is sufficient chip room space immediately axially near the insert sheet 110, and therefore implicitly, also in the axially extended portion of the cutting insert 114. A sufficiently large chip room 146 is required to effectively transfer the chip away from the workpiece.

[0069] The shape of the chip room 146 disclosed herein is made possible by free-form ball nose milling.

[0070] The differential pitch invention disclosed in relation to Figures 1 to 3 can be combined with the present invention relating to the shape of the chip room 146 disclosed in relation to Figures 1, 4, and 5 to realize a milling tool that combines the advantages of these concepts.

[0071] The present invention is shown with a milling tool 100 incorporating five cutting inserts 114. However, embodiments of the present invention can be equally carried out with a milling tool 100 having other numbers of cutting inserts 114, such as eight, ten, twelve, or twenty, but are not limited to these. The minimum number of cutting inserts 114 is three.

[0072] The present invention is shown incorporated into an end mill tool. However, some of the illustrated embodiments can be equally carried out with a groove milling tool.

Claims

1. A metal cutting milling tool (100), It has a body that can rotate in the rotational direction around a central axis (C), The aforementioned main body, - Front end (106) and, - A plurality of land portions (156) extending axially rearward from the front end portion (106), - A plurality of chip rooms (146) extending axially rearward from the front end and Equipped with, - Each of the plurality of land portions (156) is bounded by a front surface (157) and a rear surface (158) when viewed in the rotational direction, the front surface (157) is in the rotational forward direction of the rear surface (158), and each land portion (156) as part of the front surface (157) in the radially outward front region is provided with an insert sheet (110) for receiving a cutting insert (114), - Each of the plurality of chip rooms (146) is located between two adjacent land portions (156) of the plurality of land portions, and each chip room (146) is bounded by a chip room surface that includes the rear surface (158) of the first land portion (156), the front surface (157) of the second land portion (156), and the bottom surface located between the rear surface (158) and the front surface (157), and the first land portion (156) is in the rotational forward direction of the second land portion (156), and when viewed in a cross section perpendicular to the central axis (C), each chip room surface has a curvature with a minimum radius (r), The minimum radius (r2) of the second cross section and the minimum radius (r3) of the third cross section are greater than the minimum radius (r1) of the first cross section, the first cross section is located axially forward of the second and third cross sections, the first cross section is located in the region where the insert sheet (110) is positioned with respect to the central axis (C), and the second and third cross sections are located axially further from the front end portion (106) than the region where the insert sheet (110) is positioned. A metal cutting milling tool characterized in that the depth of the chip room (146) in the third cross-section is smaller than the depth of the chip room (146) in the first cross-section.

2. The metal cutting milling tool according to claim 1, wherein the minimum radius (r3) of the third cross-section is greater than the minimum radius (r2) of the second cross-section.

3. The metal cutting milling tool according to claim 2, wherein the minimum radius (r) increases strictly between the minimum radius (r2) of the second cross-section and the minimum radius (r3) of the third cross-section.

4. The metal cutting milling tool according to claim 2 or 3, wherein the minimum radius (r) increases linearly between the minimum radius (r2) of the second cross-section and the minimum radius (r3) of the third cross-section.

5. The metal cutting milling tool according to any one of claims 1 to 4, wherein the minimum radius (r) is constant in all cross-sections along the axial length of the insert sheet (110).

6. A metal cutting milling tool according to any one of claims 1 to 5, wherein the minimum radius (r3) of the third cross-section is 2 to 4 times the minimum radius (r1) of the first cross-section.

7. The metal cutting milling tool according to any one of claims 1 to 6, wherein the minimum radius (r3) of the third cross-section is 2 to 10 mm.

8. The metal cutting milling tool according to any one of claims 1 to 7, wherein the bottom surface of the chip room (146) in all cross-sections between the second cross-section and the third cross-section has the shape of an arc (r4) in a cross-section parallel to the longitudinal direction of the chip room (146).

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