阅读说明：本技术 用于窄宽度的切断操作的高速进给的切断刀片 (High speed feed severing blade for narrow width severing operations ) 是由 雅各布·居伊 于 2018-10-24 设计创作，主要内容包括：用于达到0.4mm/rev的相对较高速的进给的切断刀片(16)包括前刀面(22),该前刀面包括在两个凸形拐角子刃(66,68)之间延伸的前子刃(60)。在第一和第二凸形拐角子刃(66,68)的远端点之间定义切削宽度W<Sub>C</Sub>。切削宽度W<Sub>C</Sub>满足以下条件：W<Sub>C</Sub>≤6mm。前子刃(60)包括具有满足以下条件的最小前子刃厚度T<Sub>F</Sub>的刃带：T<Sub>F</Sub>＞0.20mm。(A severing insert (16) for relatively high speed feeds up to 0.4mm/rev includes a rake surface (22) including a rake sub-edge (60) extending between two convex corner sub-edges (66, 68). A cutting width W is defined between distal points of the first and second convex corner sub-edges (66, 68) C . Cutting width W C The following conditions are satisfied: w C Less than or equal to 6 mm. The front sub-edge (60) comprises a minimum front sub-edge thickness T which satisfies the following conditions F The margin of (2): t is F ＞0.20mm。)

1. A narrow width severing blade comprising:

a handle; and

a cutting portion connected to the shank portion and defining a cutting direction from the shank portion toward the cutting portion and a rearward direction opposite the cutting direction;

the cutting portion includes:

a rake face;

a support surface comprising at least a support surface seat located below the rake surface, a downward direction being defined from the rake surface towards the support surface seat;

a rake release surface connected to the rake surface and the support surface and being a forwardmost surface of the cutting portion, the rake release surface extending downwardly from the rake surface;

a first side relief surface connected to the front relief surface and the rake surface, the first side relief surface extending rearwardly from the front relief surface and downwardly from the rake surface;

a second side relief surface connected to the front relief surface and the rake surface, the second side relief surface extending rearwardly from the front relief surface and downwardly from the rake surface; and

a cutting edge;

the cutting edge includes:

a reinforced rake sub-edge formed at the intersection of the rake surface and the front relief surface;

a first side sub-edge formed at an intersection of the rake surface and the first side relief surface;

a second side sub-edge formed at an intersection of the rake surface and the second side relief surface;

a first convex corner sub-edge connecting the front sub-edge and the first side sub-edge and having a first radius R₁(ii) a And

a second convex corner sub-edge connecting the front sub-edge and the second side sub-edge and having a second radius R₂；

The rake face including a chip forming formation located rearwardly of the leading sub-edge and extending downwardly or downwardly and rearwardly from the leading sub-edge;

defining a cutting width W from a first point of the first convex corner sub-edge distal from the second convex corner sub-edge to a second point of the second convex corner sub-edge distal from the first convex corner sub-edge_C；

Defining a minimum leading sub-edge thickness T from a forwardmost point of the leading sub-edge to a closest point where the leading sub-edge intersects the chip forming structure_F；

Wherein:

a top aspect ratio R of the front sub-blade_T＝W_C/T_FLess than 30;

the cutting width W_CSatisfies W_CThe condition of less than or equal to 6 mm; and is

The minimum front sub-blade thickness T_FThe following conditions are satisfied: t is_F＞0.20mm。

2. The severing blade of claim 1, wherein said cutting width W_CThe following conditions are satisfied: w is not less than 2.5mm_C≤4mm。

3. The severing blade of claim 1 or 2, wherein said minimum leading sub-edge thickness T_FThe following conditions are satisfied: t is_F＞0.25mm。

4. The severing insert according to any one of claims 1 to 3, wherein the support surface seats extend parallel to the rake surface.

5. The severing insert according to any one of claims 1 to 4, wherein the front release surface extends downwardly and rearwardly from the rake surface; the first side release surface extending rearwardly and inwardly from the front release surface; and the second side release surface extends rearwardly and inwardly from the front release surface.

6. The cutting insert according to any one of claims 1 to 5, wherein the front sub-edge is straight in a plan view of the rake face.

7. The severing blade of any one of claims 1 to 6, wherein the front sub-edge has a uniform thickness.

8. The severing blade of any of claims 1 to 7, wherein the first radius R₁The following conditions are satisfied: r₁Is more than 0.20 mm; and the second radius R₂The following conditions are satisfied: r₂＞0.20mm。

9. The severing blade of claim 8, wherein the first radius R₁Satisfy the followingA piece: r₁Is more than 0.30 mm; and the second radius R₂The following conditions are satisfied: r₂＞0.30mm。

10. The severing blade of claim 8 or 9, wherein the first radius R₁The following conditions are satisfied: r₁Less than 0.60 mm; and the second radius R₂The following conditions are satisfied: r₂＜0.60mm。

11. The severing blade of claim 10, wherein the first radius R₁The following conditions are satisfied: r₁Less than 0.45 mm; and the second radius R₂The following conditions are satisfied: r₂＜0.45mm。

12. The severing blade of any of claims 1 to 11, wherein the blade comprises only a single cutting edge.

13. The cutting insert according to any one of claims 1 to 12, wherein a cutting width W at the cutting edge in a plan view of the rake face_CIs the largest dimension of the insert perpendicular to the cutting direction.

14. The severing insert according to any of claims 1 to 13, wherein the chip forming structure comprises only a single recess.

15. The cutting insert according to any one of claims 1 to 14, wherein a coolant groove is formed on an upper surface of the shank in a plan view of the rake face, the coolant groove extending toward the rake face.

16. The severing blade of any one of claims 1 to 15, wherein the support surface is formed with a support lateral securing structure.

17. The guillotine blade of claim 16, wherein the support lateral securing structure is located on the support surface seat.

18. The severing blade of any of claims 1 to 17, wherein the rear surface of the blade comprises a rear transverse securing structure.

19. The severing insert according to any one of claims 1 to 18, wherein the support surface comprises a support surface abutment extending downwardly from the support surface seat.

20. The severing insert according to claim 19, wherein the support surface abutment extends downwardly and rearwardly.

21. The severing insert according to claim 19 or 20, wherein the support surface abutment is free of lateral securing structures.

22. The cutting insert according to any one of claims 19 to 21 wherein the support surface comprises a bottom surface portion extending rearwardly from a support surface abutment to a rear surface of the insert.

23. The severing blade of any of claims 1 to 22, wherein the only surfaces of the blade having the transverse securing structure are the support surface seat and the rear surface.

24. The severing blade of any one of claims 1 to 23, wherein the blade has a solid construction.

25. The severing blade of any one of claims 1 to 24, wherein the shank extends further downward or downward and rearward behind a region of connection of the shank with the cutting portion.

Technical Field

The subject matter of the present application relates to a small (i.e., narrow) width cutting insert (hereinafter also referred to as "insert"), particularly for machining steel at high feed rates, and a tool including the same.

Background

One type of severing blade is disclosed in US7,326,007, the disclosure of which is incorporated herein by reference. In particular, the insert geometry, abutment surfaces, cutter and cavity geometry are incorporated herein by reference.

One type of knife (i.e., a severing blade) and knife holder (i.e., an insert holder) is disclosed in US9,259,788, the disclosure of which is incorporated herein by reference. In particular, the geometry of the tool and its cavity, as well as the tool holder, are incorporated herein by reference.

The cutting blade preferably has the smallest possible width (perpendicular to the cutting direction) to minimize waste of material. In US7,326,007, a resilient clamping structure for holding a cutting blade is disclosed. A significant advantage of this chuckless design is the ability to achieve relatively narrow machining widths, since the insert width and tool width do not need to accommodate a clamp or screw shank. Nevertheless, in order to prevent such displacement of the elastically retained insert, different solutions have been proposed, including screws and clamps.

US7,578,640 discloses a blade similar to US7,326,007 with some design modifications and also including a screw that clamps the rear of the blade to prevent displacement.

US2017/0151612 discloses a blade similar to US7,326,007 with some design modifications and also including a clamp for clamping the rear of the blade for heavy machining.

It will be appreciated that the conditions for relatively high speed feed are limited not only by the cavity strength and type of tool (which is addressed in the above solution using screws and clamps), but also by the insert itself, which may fail if it is subjected to too much force for its size.

A booklet titled "Y-axis cut" by santrvik cola (Sandvik corpant) (identification number C-1040:Sandvik Coromant 2017) discloses a resiliently held severing blade in which the blade orientation has been rotated 90 degrees to allow for higher feed rates. Notably, it is said that while using the same blade and adapter, higher feed rates are permitted by providing greater stability.

In online video using a demonstration of Y-axis cut-off (entitled "corout QD remove Three times fed rate with Y-axis cutting)"; web site addresses https:// www.youtube.com/watch.

It is an object of the present application to provide new and improved inserts, tools and tool assemblies therefor.

Disclosure of Invention

According to a first aspect of the present invention, there is provided a narrow width cutting blade comprising: a handle; a cutting portion connected to the shank portion; and a cutting edge; the cutting edge comprises a reinforced leading sub-edge formed at the intersection of the rake surface and the leading relief surface; cutting width W of cutting edge_CThe following conditions are satisfied: w_CLess than or equal to 6mm and the minimum front sub-blade thickness T of the front sub-blade_FThe following conditions are satisfied: t is_F＞0.20mm。

Top aspect ratio R of the front sub-blade_TSatisfy R_T＝W_C/T_FA condition of < 30.

According to a second aspect of the present invention, there is provided a narrow width cutting blade comprising: a handle; and a cutting portion connected to the shank portion and defining a cutting direction from the shank portion toward the cutting portion and a rearward direction opposite the cutting direction; the cutting portion includes: a rake face; a support surface comprising at least a support surface seat located below the rake surface, a downward direction being defined from the rake surface towards the support surface seat; a front relief surface connected to the rake surface and the support surface and being a forwardmost surface of the cutting portion, the front relief surface extending downwardly from the rake surface; a first side release surface connected to the front releaseA first side relief surface extending rearwardly from the front relief surface and downwardly from the rake surface; a second side relief surface connected to the front relief surface and the rake surface, the second side relief surface extending rearwardly from the front relief surface and downwardly from the rake surface; and a cutting edge; the cutting edge includes: a reinforced rake sub-edge formed at the intersection of the rake face and the rake release surface; a first side sub-edge formed at an intersection of the rake surface and the first side relief surface; a second side sub-edge formed at an intersection of the rake surface and the second side relief surface; a first convex corner sub-edge connecting the front sub-edge and the first side sub-edge and having a first radius R₁(ii) a And a second convex corner sub-edge connecting the front sub-edge and the second side sub-edge and having a second radius R₂(ii) a The rake face including a chip forming formation located rearwardly of the leading sub-edge and extending downwardly or downwardly and rearwardly from the leading sub-edge; a cutting width W is defined from a first point of the first convex corner sub-edge away from the second convex corner sub-edge to a second point of the second convex corner sub-edge away from the first convex corner sub-edge_C(ii) a Defining a minimum leading sub-edge thickness T from a forwardmost point of the leading sub-edge to a closest point where the leading sub-edge intersects the chip forming structure_F(ii) a Wherein: top aspect ratio R of the front sub-blade_T＝W_C/T_FLess than 30; cutting width W_CThe following conditions are satisfied: w_CLess than or equal to 6 mm; and a minimum leading sub-edge thickness T_FThe following conditions are satisfied: t is_F＞0.20mm。

It will be appreciated that both the first and second aspects essentially define a cutting blade having a relatively small cutting width and a relatively large minimum leading sub-edge thickness. The inventors have found that such a cutting blade provides advantages over other solutions. More specifically, the "Y-axis cut" concept described above requires a special structure that in turn requires the machining center to be able to move along the Y-axis to provide increased stability and achieve the high feed rates described above. The present invention, in turn, provides an improved blade that has been found to achieve the same feed rate as conventional tools and constructions.

For relatively small cutsThe invention provides a higher minimum leading sub-edge thickness T than previously known_F. Such a solution would minimize the leading sub-edge thickness T_FIncreased to greater than the typical prior minimum leading sub-edge thickness to provide a dedicated high speed feed blade that, as tests have shown, generally cannot operate at relatively low feed speeds. It is also expected that such geometries will not be able to machine many workpiece material types other than steel. Due to these limitations it is not surprising that the minimum leading sub-edge thickness of all other known small severing blades is very small, as this allows machining with low and high feed speeds and a plurality of different materials. Nevertheless, the specialized blade is believed to be superior to specialized equipment otherwise required to achieve higher feed rates.

The insert may include an additional cutting portion extending in a rearward direction or another direction from the shank portion.

For larger inserts (which have a larger cutting width W)_C) Larger leading sub-edge thicknesses are known. This is because the technician only scales up the thickness of each component and will not worry that larger inserts or robust tools can withstand the forces associated with machining larger chips at higher speed feeds. However, the present invention has been able to provide such higher speed feeds for even smaller blades. It has surprisingly been found that less robust tools, cavities and inserts are able to withstand higher chip forces at speeds much higher than normal feed rates. Of course, this is preferred because smaller blades and cutters are more economical. In addition, a smaller cutting width results in less waste of workpiece material.

Even more surprisingly, it has been found that when machining is carried out at a relatively high feed rate with a relatively large leading sub-edge thickness, a significantly longer tool life is achieved than when machining is carried out at a standard feed rate with a standard leading sub-edge thickness.

In view of the above, the present invention can machine faster (due to higher feed rates), require fewer blade changes (due to longer tool life), machine more workpieces (also due to longer tool life), and allow the use of conventional tools and machines.

According to a third aspect of the present invention there is provided a method of grooving or parting-off, the method comprising: moving a cutter assembly having a cutting blade according to any one of the preceding aspects in a cutting direction to slot or cut a workpiece; the movement including at least one of the sub-edges being greater than the minimum front sub-edge thickness T_FOperates at a feed rate per revolution.

It will be appreciated that a smaller cutting width is preferred because there is less waste of material in the severing operation, but there are limits to the structural strength of the blade for high speed feed operations. Therefore, preferably, the cutting width W_CThe following conditions are satisfied: w_C< 5mm, or even W_CIs less than 4 mm. It will be understood that the cutting width W_CThe lower limit of (c) is consistent with the desired processing parameters. In short, the cutting width W_CThe most preferred ranges of (a) are: w is not less than 2.5mm_CLess than or equal to 4 mm. This most preferred range allows for large cutting forces while providing a narrow cutting width, which minimizes material cutting waste. It will be appreciated that the cutting blade may also be used for the grooving operation if desired.

Similarly, increasing the minimum leading sub-edge thickness can result in greater feed rates, but this also increases the force on the blade and has limitations on machine performance (speed, etc.). Therefore, it is preferable that the minimum leading sub-edge thickness T_FThe following conditions are satisfied: t is_F＞0.25mm，T_F> 0.30mm, or even T_F> 0.35 mm. At this stage, a number of values have been tested and the upper limit (if any) of the concept has not been found. In general, the feed rate should be greater than the minimum leading sub-edge thickness T_F. For example, if the minimum leading sub-edge thickness T_FAt 0.25mm, the recommended feed rate will be 0.30mm/rev or 0.35 mm/rev. If a feed speed of 0.20mm/rev is used for a blade having such a leading sub-edge thickness, it can be expected that the machining may fail. Tests to date do show that this is an accurate assumption. Thus, the minimum front sub-edge thickness T_FIs preferred because it is preferred that each of the larger values ofWith the above advantages, external factors such as machine performance (speed, etc.) may limit the design features from being larger. Further, it is expected that machine operators will be reluctant to operate at such high feed rates because of fear of damage or direct failure. Nevertheless, when the external factors are removed, it is considered that the thickness can be increased even above the above-mentioned value, with a corresponding increase in the feed rate. In summary, even higher values are feasible, and the leading sub-edge thickness T has been successfully tested_FValues of (3) 0.25mm and 0.35 mm. Thus, a preferred but non-limiting range is 0.20mm ≦ T_F0.40mm or less, and even more preferably in the range of 0.25mm T or less_FLess than or equal to 0.35 mm. As mentioned, the leading sub-edge thickness T is not excluded_FLarger values of (b) may provide suitable results in the future.

In recent tests it has been found that, although not optimal, it is exactly equal to the sub-edge thickness T_FThe feed rate of (a) also provides surprisingly good results. For example, if the leading sub-edge thickness T_FAt 0.25mm, the recommended feed rate will be 0.25mm/rev or higher.

For the cutting operation, it is preferable that the rake sub-edge is straight in a plan view of the rake face. Note that in cutting applications, a circular leading sub-edge has poor chip evacuation performance, so a straight leading sub-edge is preferred. Even more preferably, the rake sub-edge is perpendicular to the cutting direction in plan view of the rake face. This is also due to chip removal considerations and/or dead centre (dead centre) size considerations.

Greater sub-blade thickness T_FAnd radius R is less preferred because better chip shape can be obtained with known thickness and radius.

According to some embodiments, it may be preferred that the front sub-edge is straight in a view of the front release surface in a rearward direction.

According to some embodiments, it may be preferred that the front sub-edge has a uniform thickness.

It will be appreciated that increased radial dimensions are preferred for structural strength in high speed feed operations. However, as described above, in the cutting-off operationAfter the operation is performed, a dead center is left at the center of the workpiece. The larger the radius of the cutting edge, the larger the tip. It will be appreciated that larger radii also undesirably bend the cutter holding the blade at the end of the severing operation. Nevertheless, for such feed conditions, an enhanced radius is highly desirable. It has been found after testing that the tip size increases only slightly with increasing radius, which allows the insert of the present invention to have a significantly larger minimum leading sub-edge thickness (which does not significantly affect the machining quality) and a moderately larger (i.e., sufficient) radius to maintain structural strength, while not unduly increasing the tip size. Although the first radius and the second radius are not necessarily the same, for the sake of brevity, both will be treated together. Therefore, it is preferable that the first radius R₁The following conditions are satisfied: r₁Is more than 0.20 mm; and a second radius R₂The following conditions are satisfied: r₂> 0.20mm, preferably they can satisfy the following conditions: r₁＞0.30mm，R₂> 0.30mm, or even R₁> 0.35mm, and R₂> 0.35 mm. However, according to theory, the theoretical upper limit for acceptable performance is believed to be R₁< 0.60mm and R₂Less than 0.60 mm. Even more preferably, R₁The following conditions should be satisfied: r₁< 0.45mm, and a second radius R₂The following conditions should be satisfied: r₂＜0.45mm。

Some preferred overall blade geometries will now be discussed.

Preferably, the support surface seats extend parallel or substantially parallel to the rake face. It will be appreciated that for high speed feed applications it is advantageous to support the insert directly below the rake face (participating in the cut).

Generally, for the cutting operation, it is preferable to release the surface of the cutting portion. Thus, each of the following features is preferred, individually and/or in combination:

-a front relief surface extending downwardly and rearwardly from the rake surface;

-a first side release surface extending rearwardly and inwardly from the front release surface;

-a first side relief surface extending downwardly and inwardly from the rake surface;

-a second side relief surface extending downwardly and inwardly from the rake surface;

-a second side release surface extending rearwardly and inwardly from the front release surface; and is

-wherein the second side relief surface extends downwardly and inwardly from the rake surface.

For clarity, although the above aspects may define the direction as, for example, "downward" and the specification (e.g., the preceding paragraph) may further define the same element as, for example, "downward and rearward," it will be understood that the initial direction "downward" refers to generally. In this way, further illustrations are also possible, so that the surface can also extend downwards and backwards or downwards and forwards, as long as a downward component is still present. For example, with respect to the front release surface, it will be noted that it may also be oriented downward and forward as long as the overall orientation of the blade in the cavity provides release during a severing operation.

With respect to direction, it will be understood that the cutting direction of such inserts is well known in the art for severing and/or grooving operations. That is, the cutting insert is moved into the workpiece in a single direction to perform such an operation. For the purpose of illustrating the geometry of the insert, the cutting direction also constitutes the forward direction of the insert.

The present application relates generally to blades for severing operations. It will be appreciated that such inserts are also suitable for grooving operations, as the difference is that grooving operations require only a relatively small depth of cut (relative to the size of the workpiece).

Thus, the advantageous cutting portion configurations discussed above may be applied to any number of different types of inserts. For example, it may be implemented on a pentagonal blade of the type disclosed in US9,174,279, the disclosure of which is incorporated herein by reference.

Nevertheless, the most difficult cutting operation is for relatively long overhangs, which can significantly increase the chances of instability and failure and wear. Such as the cutting blade and knife assembly shown in US9,259,788. The long overhang is typically machined with a blade having a single cutting edge so that the entire blade can enter the workpiece.

Thus, in some embodiments, the insert includes only a single cutting edge. It is also possible to twist the insert so that only one cutting edge can be operated while the other cutting edge can be inserted into the workpiece. Therefore, additionally or alternatively, it is preferable that the cutting width W at the cutting edge in a plan view of the rake face_CIs the largest dimension of the insert perpendicular to the cutting direction.

It will also be noted that the provision of screw holes or clamps increases the size of the cutting insert and thus increases its cutting width, or decreases its cutting depth. Inserts according to some preferred embodiments have a solid structure (i.e., no screw holes or any holes, or even no partial structure for receiving screws or clamps).

Thus, for the discussion of US9174279, it will be understood that the insert may comprise a further cutting portion extending in a rearward direction or another direction from the shank, or a circumferentially extending cutting portion or the like. It will also be understood that a shank is defined as the portion of the insert that is configured to be mounted to the tool, more specifically to the cavity. Such formations may be in the form of screw holes, abutment surfaces, lateral securing formations or the like. Similarly, a cutting portion refers to a portion of the insert configured to participate in cutting.

Although it is contemplated that different chip forming structures may provide suitable performance. Tests have been performed with the chip forming structure shown (i.e. comprising only a single recess). Thus, such a structure that has been successfully tested is, of course, the preferred chip-forming structure.

It will be appreciated that the optimum design is for the insert to be as small as possible. According to the tested inserts, it is preferred that the sintered volume of the inserts with cutting widths of 5mm or less is less than 260mm³. It will be appreciated that for inserts having a cutting width of 4mm or less, it may be preferred that the volume after sintering is less than 140mm³For an insert having a cutting width of 3mm or less, it may be preferable that the volume after sintering is less than 100mm³。

Finally, it is noted that the preferred blade geometry is that shown in the figures of the present application and also shown for example in US7,326,007 and US9,259,788. This blade geometry has particular advantages for the ultra-high feed rates contemplated by the present invention. As shown in fig. 1A, the exceptionally large chips 20 shown schematically are advantageously unobstructed by the insert upper clamp or edge. It will be appreciated that such insert geometries and/or insert-retaining cutters clamp the insert only at the lower surface and not near its rake surface. Thus, such large and fast moving chips do not damage any upper holder or edge of the tool during machining in extremely high feed conditions.

Thus, according to a preferred blade geometry, the blade may comprise the following features, individually and/or in combination:

the support surface may be formed with a support lateral securing structure; the support lateral securing structure may be located on the support surface seat; the support lateral securing structure may include a support groove extending parallel to the cutting direction and having opposite support side groove surfaces extending inwardly and upwardly;

the rear surface of the blade may comprise a rear transverse securing formation; the rear transverse securing structure may include a rear slot extending orthogonally to the rake surface and having opposed rear slot side surfaces extending inwardly and forwardly;

the support surface may comprise a support surface abutment extending downwardly from the support surface seat; the support surface abutment may extend downward and rearward; the support surface abutment may be free of lateral securing structure;

the support surface may comprise a bottom surface portion extending rearwardly from the support surface abutment to the rear surface of the insert;

the surface of the blade with the transverse securing structure may be only the support surface seat and the rear surface;

behind the connecting region of the shank and the cutting portion, the shank can extend further downwards or downwards and rearwards; and

the handle extends only further downwards.

While such inserts with coolant configurations are not known, they are considered ideal for current high speed feed applications. Particularly when high pressure coolant is used to assist in chip breaking. Thus, in some embodiments, a coolant groove may be formed at the upper surface of the shank in plan view of the rake face, the coolant groove extending toward the rake face. The cooling liquid groove can be opened to the front knife face. The coolant slot may be open to a rear surface of the insert located at a rear surface opposite the front release surface.

With the above description in mind, and in accordance with a fourth aspect, there is provided a tool (e.g., a severing blade) or tool assembly (tool holder, tool, and blade in accordance with any of the above aspects) for high-feed severing operations.

The cutter may be formed with a cavity for holding a cutting blade. The tool may have a tool thickness T measured perpendicular to the cutting direction at least below the cavity_BThe thickness is less than the cutting width of the blade. In some embodiments, the tool thickness T of the entire tool is preferred_BNarrower than the cutting width of the insert.

The cavity may preferably be a resilient cavity (i.e., configured to resiliently hold the insert without screws or clamps, allowing for a smaller cutting width and/or tool width).

The resilient cavity may preferably be configured to contact only the support surface and the rear surface of the blade. In other words, the tool may be devoid of any elements extending above the tool cavity.

Drawings

For a better understanding of the subject matter of the present application, and to show how the same may be carried into effect in practice, reference will now be made to the accompanying drawings, in which:

FIG. 1A is a side view of a tool assembly schematically machining a workpiece;

FIG. 1B is a plan view of the cutter assembly and workpiece of FIG. 1A;

FIG. 1C is a front view of the cutter assembly of FIG. 1A without the workpiece (also referred to as a front view in a rearward direction);

FIG. 2A is a first side perspective view of the cutting insert of the cutter assembly of FIG. 1A;

FIG. 2B is a second side perspective view of the cutting insert of FIG. 2A;

fig. 2C is a top view of the cutting insert in fig. 2A (also referred to as a plan view of the rake surface or a view in a downward direction toward the rake surface);

fig. 2D is a front view of the cutting insert of fig. 2A (also referred to as a view of the front surface in a rearward direction);

FIG. 2E is a top view of the cutting insert corresponding to the view of FIG. 2C;

FIG. 2F is a side view of the cutting insert of FIG. 2A;

FIG. 2G is a bottom view of the cutting insert of FIG. 2A; and

fig. 2H is a rear view of the cutting insert of fig. 2A.

Detailed Description

Referring to fig. 1A-1C, an exemplary tool assembly 10 is shown that includes a tool holder 12, a tool 14, a solid cutoff insert 16, and a steel workpiece 18 that is machined with chips 20 (shown schematically) in fig. 1A.

As will be understood from fig. 1A and 1B, the cutting direction D is known in the art_CIs defined as the direction in which the blade 16 moves into the workpiece 18. Alternatively, this may be defined as a direction parallel to the rake surface 22 and toward the front release surface 24 of the blade 16 (fig. 1C). In the backward direction D_RIs defined as the direction D of cutting (or forward direction)_CThe opposite is true.

Downward direction D_DDefined as the direction from the rake surface 22 toward the support surface seat 26. Upward direction D_UIs defined as corresponding to the downward direction D_DThe opposite is true.

For good order, the first side direction D_S1And a second side direction D_S2Is defined as the direction of cutting D_CIn the backward direction D_RDownward direction D_DAnd an upward direction D_UAre orthogonal. It will be understood from the following drawings that the inward or outward direction of the blade is more relevant to understanding the geometry relative to other features of the blade, and that these particular designations are "upward"," downward "and" lateral "are for convenience only. As is well known, such a tool assembly 10 may also operate upside down.

The exemplary knife assembly 10 shown has a knife 14, the knife 14 being a cutting blade configured for particularly long overhangs. Thus, the tool thickness T of the tool 14_BSmaller than the cutting width W of the insert_C. Thus, the tool 14 may enter the workpiece 18 until, for example, the workpiece reaches the tool holder 12 (or cannot maintain stability).

The cutter 14 includes a resilient cavity 28 that contacts only a support surface 30 and a rear surface 32 of the insert 16.

Referring now to fig. 2A-2H, the present invention will be described with reference to preferred but non-limiting blade geometries.

The insert 16 includes an exemplary, but non-limiting, shank portion 34 and a cutting portion 36. As shown, the shank extends downwardly in spaced relation to the cutting portion 36, in this example only downwardly.

The blade 16 may be defined to include the following surfaces: a front release surface 24, a rear surface 32 opposite the front release surface 24, an upper surface 38, a support surface 30 opposite the upper surface 38, and first and second side surfaces 40, 42 connecting the front release surface 24, the rear surface 32, the upper surface 38, and the support surface 30.

As best shown in fig. 2F, the front relief surface 24 extends downwardly and rearwardly from the rake surface 22.

The rear surface 32 includes a rear transverse securing structure 44. More specifically, the rear transverse fixation structure 44 includes a rear slot 46, the rear slot 46 having opposed rear slot side surfaces 48, 50 extending inwardly and forwardly (see, e.g., fig. 2C).

In theory, the upper surface 38 may be divided into the rake surface 22 at the cutting portion 36 and the shank upper surface 52.

The rake surface 22 includes a cutting edge 54 and a chip forming structure 56 having a single recess 58.

The cutting edge 54 comprises a leading sub-edge 60, a first side sub-edge 62, a second side sub-edge 64, having a first radius R₁And has a second radius R₂And a second convex corner sub-edge 68.

As illustrated in this non-limiting example, the front sub-edge 60 is straight in a plan view of the rake face 22 (see fig. 2C), extends perpendicular to the cutting direction (see fig. 2C), is straight in a view of the front relief surface in the rearward direction (see fig. 2D), and has a uniform thickness T_F(see FIG. 2C). Thickness T_FIncreasing the rigidity and thereby strengthening the leading sub-edge 60 even in the cutting direction D_CThe service life of the blade is prolonged when the cutting is carried out at a feeding speed higher than the normal feeding speed. Thus, in a sense, the leading sub-edge 60 may be considered to have a reinforced "margin" that is parallel to the cutting direction D_CHas an increasing thickness in the direction of (a).

For clarity only, the respective arcuate extensions of the first and second convex corner sub-edges 66, 68 may form an imaginary circle C_I(only one is shown in FIG. 2C), and a circle C_IRadius of (a) provides a radius R₁、R₂The value of (c).

As shown in more detail in fig. 2C, the cutting width W_CIs defined from a first point 82 of the first convex corner sub-edge 66 to a second point 84 of the second convex corner sub-edge 68. The blade according to the subject matter of the present application has a front sub-edge 60 of narrow width. For the present purposes, a "narrow width" leading sub-edge 60 is defined as a leading sub-edge having a cutting width of less than or equal to 6 mm. However, in some embodiments and for some applications, the cutting width of the leading sub-edge 60 may be smaller, such as no greater than 4mm, or preferably no greater than 3 mm. Although it is not known how the lower limit of such a narrow cutting blade may be in the future, it is theoretically considered that the minimum cutting width practically usable at present is 2mm or more. The currently preferred range of values is from 2.5mm to 4.5 mm. This optimum range is a compromise between the minimum insert size that can handle the considerable cutting force loads and the desire to have the cutting width as small as possible to reduce wasted material.

The top aspect ratio R of the leading sub-edge 60 is seen in a top view of the blade_TIs defined as a cutting width W_CAnd thickness T_FRatio (see fig. 2C);namely, R_T＝W_C/T_F. The top aspect ratio of the blade according to the subject matter of the present application is less than 30; namely R_T＜30。

The shank upper surface 52 may include a coolant formation 70. The coolant configuration 70 may include a coolant trough 72. The coolant groove 72 may open to the rake surface 22 at a coolant front opening 74. The coolant slot 72 may open to the rear surface 32 at a coolant rear opening 76.

The first side surface 40 may include a first side release surface 78 (fig. 2A). The first side release surface 78 can extend rearwardly and inwardly from the front release surface 24 (fig. 2G) and can extend downwardly and inwardly from the rake surface 22 (fig. 2D).

The second side surface 42 may include a second side release surface 80 (fig. 2A). The second side release surface 80 can extend rearwardly and inwardly from the front release surface 24 (fig. 2G) and can extend downwardly and inwardly from the rake surface 22 (fig. 2D).

Referring to fig. 2F, the support surface 30 may include a support surface seat 26, a support surface abutment 86, and a bottom surface portion 88.

The support surface seat 26 may be formed with a support lateral securing structure 90 (fig. 2A). The support lateral securing structure 90 may include a support channel 92 and inwardly and upwardly extending opposing support channel side surfaces 94, 96.

The support surface abutment 86 provides an opposing abutment surface to the rear surface 32. Preferably, the support surface abutment 86 has no lateral securing structure. However, it will be appreciated that alternative locations for the lateral fixation structure are possible, although less preferred. Alternatively, instead of grooves, protrusions may be provided.

The following detailed description differs only in the minimum leading sub-edge thickness T_FAnd a radius R₁、R₂Exemplary severing test results for the severing blade according to the invention and the comparative blade.

In the cut-off test, both blades were made of the same grade of material, both having a W_C4mm, cutting speed V_CSet to 100 m/min. The maximum wear is defined as 0.25 mm.

The feeding speed F1 was set to the normal condition of the comparison blade (F1 ═ 0.18mm/rev, which is slightly greater than its minimum front sub-edge thickness, i.e. 0.115mm, so R_T4mm/0.115 mm-34.78). The feed speed F2 was set to the normal condition of the insert according to the invention (F2 ═ 0.4mm/rev, slightly greater than its minimum front sub-edge thickness T_FI.e. 0.3mm, so R_T＝4mm/0.3mm＝13.33)。

Radius R of the comparison blade₁、R₂Is 0.24 mm. Radius R of the insert according to the invention₁、R₂Is 0.50 mm.

In the test, the two comparative blades tested reached maximum wear after 20 minutes and 25 minutes, respectively. The two blades according to the invention reached maximum wear after 100 minutes and 110 minutes, respectively.

Thus, although both inserts were tested under normal operating conditions, the inserts according to the invention also showed a greatly unexpected improvement in tool life.

In the grooving test of the same type of insert described above, the cutting speed V_CThe feed rate was set at 200m/min and 0.4mm/rev for both. In this test, the insert according to the invention formed three times as many grooves as the comparative insert.