Cutting insert for cutting off metal workpieces

Abstract

The 2-edge insert (100) includes a first cutting part (100, 110), a second cutting part (112), and an elongated body part (114) connecting the first and second cutting parts. The elongated body part (114) has a body width (BW) measurable parallel to the transverse axis and a body length (BL) measurable parallel to the elongation axis. The body width is smaller than the cutting widths of the cutting edges of the first and second body parts and satisfies the condition: 0.55 mm < BW < 0.95 mm, and the body length satisfies the condition: 2 mm < BL < 14 mm.

Description

[Technical Field]

[0001] The subject matter of the present invention relates to cemented carbide cutting inserts (hereinafter "parting inserts" or "inserts" for brevity) for parting off metal workpieces. [Background technology]

[0002] The present invention relates to an insert for cutting off a metal workpiece. It will be understood that an insert configured for cut-off is also configured for grooving, since both cut-off and grooving involve similar machining steps. That is, both operations involve only forward movement relative to the workpiece (in other words, no lateral or transverse movement component). The difference between a cut-off operation and a grooving operation is merely the extent to which the cutting edge of the insert penetrates the workpiece, cutting or machining a slit-shaped cutting portion (an example of a slit-shaped cutting portion of the type described is shown in FIG. 7B of WO 2022 / 084992, designated "S"; hereinafter also referred to as a "slit"). In a grooving operation, unlike a cut-off operation, the slit extends relatively little into the workpiece, i.e., less than about halfway through the rotating workpiece, and therefore does not "cut off" the workpiece into two separate pieces. In a cut-off operation, the slit-shaped cut extends far enough into the workpiece to separate it (i.e., completely separate a portion from the workpiece).

[0003] For clarity, the inserts will be referred to as parting inserts in the specification and claims of this application, but it should be understood that such parting inserts are also configured to essentially create slit grooves of the type shown in WO2022 / 084992.

[0004] To create the slit, the cutting edge of the insert extends along the entire lateral (i.e., sideways or transversely perpendicular to the forward direction) length of the insert. The lateral extent of the cutting edge, including the corners, is referred to as the cutting width (commonly designated "CW" as illustrated and shown in Figure 2C of US 11,278,968, although in that publication the cutting width is also referred to as the "cutting width W"). C").

[0005] In particular, the present invention includes so-called neutral left-right inserts, in which, in a plan view of the rake face (such a plan view is exemplified in FIG. 2C of U.S. Pat. No. 11,278,968, although other names for such views are interchangeable as indicated in said publication), the cutting edges may extend perpendicularly or obliquely in the forward direction. See FIGS. 2, 3, and 4 of the present application, which show plan views of the rake faces of the inserts. Each of the inserts is identical except that it is a neutral left-right insert.

[0006] In more detail, referring to FIG. 2 of the present application, the extension axis A E The elongated insert 100 is shown along the axis of elongation A. E is the forward (or cutting) direction D F and forward D F and the opposite direction D R For purposes of this description only, the first cutting edge 102 is selected to be the effective cutting edge, and therefore the insert defines a forward direction D F As the insert 100 moves toward a workpiece (not shown), it is used to part off or slot the workpiece. At the end opposite the first cutting edge 102 of the insert 100 is a second cutting edge 104 that only becomes active after the insert is replaced in a tool pocket (not shown).

[0007] A transverse axis A extending through the frontmost portion of the cutting edge 102 L is the extension axis A E and extends perpendicular to the first lateral direction D S1 and the first lateral direction D S1 and a second lateral direction D opposite to S2 Define the following.

[0008] For completeness, the first central axis A C1 ("Vertical axis A C1 ") passes through the center of the insert along the axis of elongation A E and horizontal axis A L Note that the radii extend perpendicular to both the radii and the radii.

[0009] The second central axis A shown in FIGS. 5C and 5D C2 passes through the center of the insert along the extension axis A L Orthogonal to the horizontal axis A L It extends parallel to.

[0010] The illustrated insert 100 has a first central axis A C1 Because of the 180° rotational symmetry around the cutting edge (i.e., the vertical axis), only the first cutting edge 102 will be described in detail.

[0011] The first cutting edge 102 is a front minor cutting edge 102A (i.e., in the forward direction D F the first minor cutting edge 102A in the base rear direction), a first left minor cutting edge 102B extending from a first corner 102D connecting the foremost minor cutting edge 102A and the first left minor cutting edge 102B in the base rear direction, and a first right minor cutting edge 102C extending from a second corner 102E connecting the foremost minor cutting edge 102A and the first right minor cutting edge 102C in the base rear direction.

[0012] The first cutting edge 102 shown in FIG. 2 is a neutral cutting edge, and the neutral cutting edge is defined as a cutting edge where the front minor cutting edge 102A is aligned with the horizontal axis A. L This means that it is essentially parallel to

[0013] In contrast, the front minor cutting edge 202A is aligned with the horizontal axis A L A so-called "left" insert 200, which is identical in all respects except for the cutting edge being inclined in the second lateral direction D, is shown in Figure 3. More precisely, the leading minor cutting edge 202A is inclined in the second lateral direction D. S2 and backward D R extends along the horizontal axis A L together forming an acute angle 204.

[0014] Similarly, the front minor cutting edge 302A is L A so-called "right" insert 300, which is identical in all respects except for the cutting edge being inclined relative to the first lateral direction D, is shown in Figure 3. More precisely, the leading minor cutting edge 302A is inclined relative to the first lateral direction D.S1 and backward D R extends along the horizontal axis A L together forming an acute angle 304.

[0015] In summary, since various cutting edge shapes are within the scope of the present invention, the lengths associated with the leading minor cutting edge 102A described and defined below should be measured from the forward-most point of the leading minor cutting edge 102A.

[0016] Below, further general problems and common parting insert features are described in relation to such inserts.

[0017] The first important consideration for parting inserts is the cutting width (CW). Generally, the cutting width (CW) of a parting insert is preferably as small as possible to reduce the loss of the workpiece being machined. However, due to considerations of strength and machining forces, operators have no choice but to select a relatively large cutting width to ensure no fracture. In U.S. Pat. No. 11,278,968, which describes an invention by the present inventor, there is a parting insert designed to offset machining forces to ensure that even smaller known inserts do not fracture under relatively high-force machining conditions. However, the general selection priority is to select the smallest possible cutting width for a given machining operation, taking into account machining forces.

[0018] Some common parting insert features are described below with reference to the numerals that represent the features in the drawings of US 11,278,968, all of which are provided to facilitate understanding of typical design features.

[0019] In the cutting portion, the front surface (24) and lateral surfaces (78, 80) adjacent to the cutting edge (i.e., extending downward from the cutting edge) are typically relieved (i.e., "flanked") so that they do not contact the slit in the workpiece formed by the cutting edge. In other words, the front surface (24) and lateral surfaces (78, 80) extend both downward and inward.

[0020] The cutting edge (54) is formed along the intersection of the so-called rake face (also called the "top face") (22) of the insert with the front face (24) and the lateral faces (78, 80).

[0021] The rake face (22) typically has a chip-forming formation (56) which usually comprises one or more downwardly extending recesses, but may alternatively, but less commonly, consist of or include upward protrusions.

[0022] Rearward of the cutting edge, in a plan view of the rake face (22), at least a portion of the insert body immediately adjacent the rake face, as well as the front face (24) and lateral faces (78, 80), is recessed from the cutting width defined by the cutting edge (see FIG. 2C). In other words, said portion is thinner than the cutting width (i.e., extends inwardly and laterally on both sides), so that the insert body does not contact the slit in the workpiece formed by the cutting edge.

[0023] Currently, the most popular material for inserts is cemented carbide. During manufacturing, cemented carbide is pressed and then sintered. During the sintering process, inserts can become distorted, especially inserts with particularly thin, elongated shapes that are desirable for small cutting widths. This is yet another significant design consideration for parting inserts.

[0024] The above-described features are typical for the type of insert to which the present invention relates (i.e., cemented carbide inserts configured for parting-off operations).

[0025] A second important consideration for parting inserts is the depth of cut (hereinafter referred to as "DC"). A relatively larger depth of cut is preferred because it enables the cutting tool to part off both smaller-diameter and larger-diameter workpieces (or deeper grooves, etc.). The depth of cut is limited by either the insert or the tool having a portion wider than the cutting edge that creates the slit. To explain, the cutting edge creates the slit, and the insert at least partially penetrates the workpiece. When the elongated portion of either the insert or the tool, in plan view of the rake face, reaches the workpiece first, the insert cannot penetrate further without undesirable impact because the elongated portion (of either the insert or the tool) cannot penetrate the slit created by the cutting edge. Therefore, in plan view of the rake face, it is preferred that at least as much of the insert as possible be thinner (i.e., recessed) than the cutting edge so as not to contact the wall of the slit being machined.

[0026] Therefore, the optimal solution is to allow unlimited depth of cut (at least from the insert) by designing the insert to be thinner overall in plan view of the rake face, thus limiting the depth of cut only by the tool.

[0027] This unlimited depth of cut may be provided in a first example by an insert having a single cutting edge, with the remainder of the cutting insert being thinner than the cutting edge in a plan view of the rake face. The single cutting edge thus provides an unlimited depth of cutting capability that is at least not limited by the insert itself, although the tool holding the insert may limit the depth of cut at some point. Hereinafter, this design will be referred to as a conventional single-cutting-edge insert (or "single-cutting-edge insert").

[0028] Perhaps the most commonly sold parting inserts are single-cutting-edge inserts (one optional example is the insert shown in US Pat. No. 1,278,968). A single-cutting-edge insert has a cutting portion, which has a rake face and a flank face extending essentially downward and inward from the rake face. A single cutting edge is formed at the intersection of the rake face and the flank face. The insert further has a shank portion rearward of the cutting portion, which is secured to or designed to hold a tool (the "tool" can be a blade or an insert holder having a square or round shank, etc.).

[0029] Thus, the third important consideration for inserts is met by the popular single-cutting inserts: that they be made with the least amount of expensive cemented carbide material possible and that they be press-to-size (i.e., do not require separate grinding, although some applications require grinding). However, press-to-size inserts generally do not have a grinding surface.

[0030] A fourth important consideration for inserts is the number of cutting edges, with each additional cutting edge being preferable because the insert can be used in machining for an overall longer amount of time (i.e., increased "tool life") before being discarded.

[0031] Thus, a second type of fairly popular parting insert is one with two cutting edges, and the additional cutting edge provides a significant benefit over a single-cutting insert. Dual-cutting inserts provide additional economic value to the user by allowing the second cutting edge to be used after the first cutting edge wears.

[0032] In the most common configuration described herein, each cutting edge is located at opposite ends of the same rake face. This design will hereafter be referred to as a conventional two-cutting-edge insert. The rake face includes a first minor rake face and a second minor rake face that are visible together in the same plan view of the rake face. In the plan view of the rake face, each minor rake face is separated by a relatively thinner, elongated body portion. In other words, the insert includes two cutting portions and a body portion extending between the two cutting portions, each of which includes a rake face with a first minor rake face and a second minor rake face, respectively.

[0033] However, the cutting depth that can be produced by such an insert is limited by the distance between the two cutting portions (i.e., where the cutting insert widens again at the point where it contacts the slit being produced, also the second minor cutting face).

[0034] Thus, conventional dual-cutting inserts have one main advantage (number of cutting edges) and one main disadvantage (depth of cut) compared to single-cutting inserts.

[0035] A moderate drawback of conventional two-edge insert designs is that the cutting width CW cannot be made as small as that of single-edge inserts (e.g., the minimum cutting width with the applicant's single-edge inserts is 0.6 mm, while the minimum cutting width with the two-edge inserts is 1.4 mm). This difference is a result of distortion during the sintering process if the elongated body portion of the conventional two-edge insert design is made unacceptably thin.

[0036] Additionally, conventional two-edge insert designs have a minor drawback: they require more material due to the need for a second cutting portion.

[0037] A known design developed to overcome the main drawback of conventional two-cutting-edge inserts, namely their limited cutting depth, is the so-called "twist insert." An example of a twist insert can be found in U.S. Pat. No. 5,156,502. Twist inserts differ from conventional two-cutting-edge inserts in that the two cutting portions are not parallel but twisted relative to each other so that the rake faces do not face in exactly the same direction. The twist insert adjusts the non-effective cutting edge so that, in plan view of the rake face of the effective cutting edge, the remainder of the insert is thinner than the cutting width CW.

[0038] The advantage of twist inserts over traditional two-edge insert designs is that they allow for unlimited depth of cut (at least relative to the insert, not the tool holding the insert).

[0039] A disadvantage of twist inserts compared to traditional two-edge inserts is that they can only be manufactured in relatively large cutting widths (especially when compared to the extremely small cutting widths of smaller single-edge inserts), and some compromises are made related to securing the insert in the pocket.

[0040] In summary, the three types of inserts that are well known and commercially available as mentioned above include single-cutting-edge inserts, which have the advantage of unlimited cutting depth and are the cheapest to manufacture; conventional two-cutting-edge inserts, which have the great advantage of a separate cutting edge compared to single-cutting-edge inserts, but are significantly more limited in cutting depth and slightly more limited in cutting width and manufacturing cost; and twist two-cutting-edge inserts, which have the advantages of both unlimited cutting depth and two cutting edges, but are more limited in cutting width than the other two.

[0041] Each solution has its advantages and disadvantages, and there is a long-felt need in the industry for a better solution. Accordingly, a number of different solutions have been devised to provide better parting inserts, and several such solutions by the applicant are described below.

[0042] One solution that has been developed is a two-cutting edge insert with an elongated center portion (sold by the applicant, Iscar Inc., under the name DO-GRIP DGN1002, hereinafter referred to as the "DGN insert") that can produce a small cutting width (1 mm), which is smaller than that of the conventional two-cutting edge inserts described above, but not as small as that of the smallest single-cutting edge insert, and of course has the benefit of two cutting edges, but is expensive to manufacture due to the elongated center portion, and its cutting depth is significantly limited (3 mm).

[0043] Yet another solution, disclosed in USP 10,363,722 B2, is a relatively large two-cutting insert without an enlarged center portion. By providing such a large insert, a relatively large cutting depth and a relatively small cutting width (stated in the patent as less than 1.5 mm) are possible. However, because the insert height is quite large, the insert is expensive due to the large amount of material and a large dedicated insert pocket is required for the insert. Summary of the Invention [Problem to be solved by the invention]

[0044] It is an object of the present invention to provide a new and improved parting insert.

[0045] Such an objective is not an easy task, as numerous solutions have been attempted for improved parting inserts, some of which have been detailed above. [Means for solving the problem]

[0046] In search of an improved parting insert, and in view of the known variations identified above, it has been devised to provide a modified cemented carbide two-cutting insert (hereinafter) having a superior (i.e. smaller) cutting width, which may be comparable in minimum cutting width range to a single-cutting insert.

[0047] It is believed that such inserts have not previously been produced due to known problems with thin, elongated inserts deforming during the sintering process.

[0048] As can be seen, it is crucial for the parting machining process that the parting insert, which is intended to enter the slit to a large extent, is straight.

[0049] Specifically, the difficulty faced by designs such as those described above is the inherent problematic nature of manufacturing very thin and elongated cemented carbide inserts, which tend to deform.

[0050] Said deformation can be countered by thickening the insert (which is not desirable here as it is preferable for the cutting width to be as small as possible), which essentially results in a conventional two-edge insert with a known cutting width.

[0051] Alternatively, the deformation can be countered by shortening the insert (reducing the distance between the thicker cutting portions is undesirable here as it results in a relatively small cutting depth and reduces the range of workpiece diameters that can be cut off), which essentially results in an insert with similar capabilities as a DGN insert.

[0052] Yet another difficulty is that regardless of the length of the insert, cutting widths as small as those achievable with conventional single-edged inserts are never obtained, since the larger sized two-edged inserts always have a larger width to avoid distortion during the sintering process.

[0053] Therefore, to minimize the possibility of distortion while still obtaining advantageous width of cut and depth of cut of some value, the present invention has been provided with a slightly disadvantageous width of cut that is greater than the smaller single-edged insert (0.6 mm), but is still less than the width of cut of the known conventional two-edged insert (1.4 mm), and therefore advantageous when compared to the known conventional two-edged insert.

[0054] To achieve this width of cut, another compromise was made: to further minimize the risk of deformation, a second step was to provide a shorter length than a conventional two-edged insert, thereby limiting the depth of cut and further reducing potential deformation. While this also reduces the range of use (i.e., only smaller diameter workpieces can be cut off), the overall benefit of a better width of cut than the already known two-edged insert, combined with the advantage of having two cutting edges over a conventional single-edged insert, is believed to provide a novel and advantageous insert with potential for at least a niche market segment.

[0055] Despite some concerns during prototyping, the dimensions set forth below were found to have sufficiently small variations to be within acceptable tolerances.

[0056] As explained above, a number of niche style inserts have been attempted, for example, the present invention has a cutting width comparable to the DGN1002 insert, yet has a significantly greater cutting depth.

[0057] Furthermore, the present invention has a smaller depth of cut and a slightly smaller width of cut than the insert described in US Pat. No. 10,363,722, but uses significantly less expensive material during manufacture.

[0058] According to a first aspect of the present invention, there is provided a dual-cutting-edge parting insert, the dual-cutting-edge parting insert comprising: a first cutting portion; a second cutting portion; an elongated body portion connecting the first cutting portion and the second cutting portion; a rake face; a base face opposite the rake face; and an outer circumferential surface connecting the rake face and the base face, the outer circumferential surface comprising: a leading minor surface in the first cutting portion; a trailing minor surface in the second cutting portion and opposite the leading minor surface; a left minor surface connecting the leading minor surface and the trailing minor surface and located on one side of the parting insert; and a right minor surface connecting the leading minor surface and the trailing minor surface and opposite the left minor surface, the body portion being elongated along an elongation axis extending through a center of the body portion, E ) is the forward direction (D F ), and the backward direction (D R ), and the parting insert defines an elongation axis (A E ) and the parting insert has an insert length (IL) measured along the elongation axis (A E ) and has a height (H) measured perpendicular to a first central axis (A C1 ) is defined as extending perpendicular to the elongation axis, through the center of the parting insert, through the base face and the rake face, and a first central axis (A C1 ) is the upward direction from the base face to the rake face (D U ) and downward direction (D D ) and defines a second central axis (A C2 ) is the extension axis (A E ) and the first central axis (A C1 ) and extending through the center of the parting insert, and a second central axis (A C2 ) in the first lateral direction (D S1 ) and the first lateral direction (D S1 ) and the opposite second lateral direction (D S2The first cutting portion includes a first minor rake surface on the rake face, a first leading flank surface on the leading minor surface, a first left minor flank surface on the left minor surface, a first right minor flank surface on the right minor surface, and a first cutting edge formed at an intersection line between the first leading minor rake surface and each of the first leading minor rake surface, the first left minor flank surface, and the first right minor flank surface, and the first cutting edge extends along the intersection line between the first minor rake surface and the first leading minor rake face. a first left minor cutting edge extending along an intersection line between the first minor rake face and the first left minor flank face; a first right minor cutting edge extending along an intersection line between the first minor rake face and the first right minor rake face; a first left corner formed at an intersection line between the first foremost minor cutting edge and the first left minor cutting edge; and a first right corner formed at an intersection line between the first foremost minor cutting edge and the first right minor cutting edge. a second minor rake surface on the rake face, a second front minor rake surface on the rake face, a second front minor rake surface on the rear minor rake face, a second left minor rake surface on the right minor rake face, a second right minor rake surface on the left minor rake face, and second cutting edges formed at the intersections of the second front minor rake surface with the second front minor rake surface, the second left minor rake surface, and the second right minor rake surface, respectively; a second foremost minor cutting edge extending along a line, a second left minor cutting edge extending along an intersection line between the second minor rake face and the second left minor flank face, a second right minor cutting edge extending along an intersection line between the second minor rake face and the second right minor rake face, a second left corner formed at an intersection line between the second foremost minor cutting edge and the second left minor cutting edge, and a second right corner formed at an intersection line between the second foremost minor cutting edge and the second right minor cutting edge, L ) extends through the front end of the first cutting edge and has a horizontal axis (A L ) is the second central axis (A C2 ) and extends parallel to the first lateral direction (D S1 ) and the first lateral direction (D S1 ) and the opposite second lateral direction (D S2), the first cutting edge has a first cutting width (CW1) measurable parallel to the horizontal axis from a first left corner to a first right corner, the second cutting edge has a second cutting width (CW2) measurable parallel to the horizontal axis from a second left corner to a second right corner, the elongated body portion has a body width (BW) measurable parallel to the horizontal axis and a body length (BL) measurable parallel to the elongation axis, the body width (BW) being smaller than both the first cutting width (CW1) and the second cutting width (CW2) and satisfying the condition: 0.55 mm≦BW≦0.95 mm, and the body length (BL) satisfying the condition: 2 mm≦BL≦14 mm.

[0059] In other words, according to a second aspect of the present invention, there is provided a two-cutting edge parting insert, the two-cutting edge parting insert comprising: a first cutting portion; a second cutting portion; a body portion connecting the first cutting portion and the second cutting portion; The scooping surface and a base surface located opposite the rake surface; an outer peripheral surface connecting the rake face and the base surface; Equipped with the first cutting portion has a rake face with a first minor rake surface; the second cutting portion has a second sub-rake surface on the rake face; the body portion has a body width (BW) measurable parallel to the transverse axis and a body length (BL) measurable parallel to the elongation axis; The body width (BW) satisfies the condition: 0.55 mm ≦ BW ≦ 0.95 mm. The body length (BW) satisfies the condition: 2 mm ≦ BL ≦ 14 mm.

[0060] It will be appreciated that, in accordance with each of the above aspects, it has been discovered that a body portion having a given dimension can be made within an acceptable amount of distortion.

[0061] Preferably, the body width (BW) satisfies the condition: 0.65 mm≦BW, more preferably 0.75 mm≦BW. It will be appreciated that increasing the body width reduces the amount of distortion. It is also preferred that BW≦0.85 mm to allow sufficient clearance from the cutting width.

[0062] While a body length of just over 2 mm is beneficial, it is known from DGN inserts that there is market demand for a cutting depth DC of only 3 mm (bearing in mind that the cutting portion itself has a certain length), so naturally, a longer body length (BL) is preferred. For example, the body length (BL) preferably satisfies the condition: 6 mm ≦ BW, more preferably 8 mm ≦ BW. It will be appreciated that an increase in body length, despite increasing distortion, makes a greater number of machining operations (e.g., parting off relatively larger workpieces) feasible. Furthermore, the present invention offers another advantage over smaller single-cutting inserts in that the overall length of the insert is longer and therefore easier to hold and move. However, a body length that is too large is considered to risk increasing distortion to an unacceptable level, and therefore the upper limit of 14 mm is specified above to avoid increasing distortion to an unacceptable amount. Preferably, the condition BL ≦ 12 mm, more preferably BL ≦ 11 mm, is satisfied.

[0063] Preferably, the first cutting width (CW1) and the second cutting width (CW2) satisfy the condition: 0.75 mm≦CW1, CW2≦1.1 mm, more preferably 0.9 mm≦CW1, CW2≦1.1 mm. It will be appreciated that this cutting width is not as advantageous as the minimum cutting width of a smaller single-cutting-edge insert (approximately 0.6 mm), but is still more advantageous than the smallest two-cutting-edge inserts currently known to the applicant. It should also be appreciated that a reduced cutting width means that the insert can handle less cutting forces, and therefore, to maintain machining feasibility at reasonable feed rates, a minimum cutting width value of 0.8 mm is preferred, more preferably 0.9 mm. Similarly, a maximum cutting width of 1.1 mm is preferred, as it provides increased benefits over the cutting widths of known conventional two-cutting-edge inserts. One most preferred cutting width is equal to 1.0 mm ± 0.04 mm. Another most preferred cutting width is equal to 0.8 mm ± 0.04 mm.

[0064] Preferably, the parting insert has a first effective length OL1, measured parallel to the elongation axis from the forward-most point of the first cutting edge to the intersection of the body portion and the second cutting portion (i.e., where the insert begins to expand relative to the body portion), satisfying the condition: 5 mm≦OL1≦15 mm. More preferably, the condition 9 mm≦OL1≦13.5 mm is satisfied, and most preferably, the condition 11 mm≦OL1≦12.5 mm is satisfied. As explained above, increasing the body length increases distortion, but makes more machining feasible and easier to hold the insert. However, an upper limit is preferred, as too large a length risks increasing distortion to unacceptable levels.

[0065] The cut-off insert has an elongated axis A E Preferably, the insert length IL satisfies the condition 4 mm≦IL≦16 mm, more preferably 11 mm≦IL≦15 mm, and most preferably 13 mm≦IL≦14 mm.

[0066] The first cutting portion 110 has an elongation axis A E The first cutting length L that can be measured parallel to C1Preferably, the first cutting portion length L C1 The condition is 1.25 mm ≦ L C1 ≦1.5mm, and most preferably 1.30mm≦L C1 The second cutting length L satisfies the condition of ≦1.40 mm. C2 The same values ​​are preferred for

[0067] Preferably, parting inserts are pressed to size (and therefore not ground, resulting in no ground surfaces). Pressing to size offers increased manufacturing advantages over larger insert varieties, such as DGN inserts and those disclosed in U.S. Pat. No. 10,363,722. In particular, ground inserts are distinguishable because they exhibit oriented lines. Specifically, one skilled in the art can determine whether an insert is ground because, even after fairly fine post-coating treatments such as polishing, the post-treatment removes material, leaving a visible pattern of parallel lines, as opposed to unground inserts, which have more random marks.

[0068] Preferably, the parting insert has a first central axis A C1 It is rotationally symmetrical by 180°.

[0069] Preferably, the height H of the body portion satisfies the condition 3.5 mm≦H≦5 mm, more preferably 4.0 mm≦H≦4.3 mm. This height H corresponds to the height of a conventional two-edged insert, and it is preferable not to reduce this dimension, as this would increase distortion without any significant benefit.

[0070] However, it has been discovered that the corners are preferably made to have a radius R that satisfies the condition 0.8 mm≦R≦1.20 mm, which is an improvement over the 0.16 mm radius of the applicant's existing conventional two-cutting inserts.

[0071] Preferably, each of the first cutting portion and the second cutting portion comprises a tip former formation, more preferably the tip former formation comprises a single recess.

[0072] The inserts are then compared using an arbitrary grading system of 1 to 5, with "1" being the lowest rating and "5" being the highest rating (relative values ​​are assigned after a detailed look at these inserts compared to each other), as well as the criteria (a) depth of cut (larger depth of cut is preferred), (b) width of cut (smaller width of cut is preferred. Values ​​shown are minimums for applicant's products and patents and are appropriate. No real-world products are sold), (c) material cost (relatively less material is preferred. Although not stated under the name "material cost," manufacturing complexity is also included in this category), and (d) use of two cutting edges (two cutting edges are preferred over a single cutting edge).

[0073] The values ​​provided below are subjective and subject to many factors, but provide an indication of the basic considerations taken into account when developing the present inserts adapted for smaller cutting width applications.

[0074] [Table 1]

[0075] Generally, the traditional single-edged inserts still have an advantage over the remaining two-edged varieties, at least in terms of minimum cutting width.

[0076] However, it is believed that it would be beneficial to introduce new two-edge inserts to the traditional two-edge insert type at inherent cutting width sizes of approximately 0.8 mm and 1 mm (or more precisely 0.8 mm ± 0.1 mm and 0.1 mm ± 0.1 mm).

[0077] After prototyping, it was discovered that at such a size, distortion was at an acceptable level.

[0078] Some caveats regarding these values ​​are as follows:

[0079] The width of cut values ​​assume an application where a smaller width of cut is desirable. For heavy duty machining applications, a smaller width of cut may not be desirable because structural strength may be preferred over workpiece material protection.

[0080] While it is fundamentally true that dual cutting edges are preferable to single cutting edges, it is not accurate to say that dual cutting edges are vastly superior to single cutting edges, since in practice, the insert will often break, meaning the operator loses the ability to utilize the second cutting edge of the same insert (which is typically a more expensive insert than a single-cutting insert).

[0081] In summary, in view of the above table, the parting insert according to the present invention is advantageous over a single cutting edge in that it has two cutting edges, but is significantly inferior to the single cutting edge in terms of depth of cut, slightly inferior in terms of width of cut, slightly advantageous over a conventional two-cutting edge insert in that it has a slightly smaller width of cut, but is inferior to the conventional two-cutting edge insert in terms of depth of cut, advantageous over a two-cutting edge twist insert in that it has a significantly smaller width of cut, but is inferior to the two-cutting edge twist insert in terms of depth of cut, advantageous over a DGN insert in that it has a larger depth of cut and is less expensive to manufacture, and slightly advantageous over the insert disclosed in USP 10,363,722 in terms of width of cut and lower manufacturing cost, but is inferior in terms of depth of cut.

[0082] For a better understanding of the subject matter of the present invention, and to show how the same may be carried out in practice, reference should now be made to the accompanying drawings, which are taken from a scale model. [Brief explanation of the drawings]

[0083] [Figure 1] 1 is a perspective view of a parting insert according to the present invention; FIG. [Figure 2] FIG. 2 is a plan view of the rake face of the insert of FIG. 1. [Figure 3] 1. FIG. 1 is a plan view of the rake face of another insert according to the present invention, which differs from the insert of FIG. 1 only in that this insert is a "left" style insert. [Figure 4] 1 and 3 only in that this insert is a "right" style insert. [Figure 5A] FIG. 2 is a front view of the insert of FIG. 1. [Figure 5B] 5B is a plan view of the rake face of the insert of FIG. 5A (the same view as FIG. 2). [Figure 5C] FIG. 5B is a right side view of the insert of FIG. 5A. [Figure 5D] FIG. 5B is a bottom view of the insert of FIG. 5A. [Figure 5E] FIG. 2 is a rear view of the insert of FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0084] Figures 1, 2 and 5A-5E show an exemplary parting insert 100 according to the present invention, which will be described in more detail below. Figures 3 and 4 also show a parting insert according to the present invention, but with the differences to the parting insert 100 described in full detail above.

[0085] The parting insert 100 comprises a first cutting portion 110, a second cutting portion 112, and an elongated body portion 114 connecting the first and second cutting portions.

[0086] The arrow designated "116" indicates the region where the cutting portion (in this example, the second cutting portion 112) transitions into the elongated body portion 114 (hereinafter "transition region 116"). This transition region 116 is visible due to the thinning of the cutting portion until the transition region 116 reaches the width of the elongated body portion, but it should also be understood that while the cutting portion is operatively connected to a cutting function (i.e., contacts a workpiece (not shown) and chips machined from the workpiece), the body portion is not configured to provide a cutting function.

[0087] The parting insert 100 further comprises a rake face 118 , a base face 120 (also referred to as the “lower face”; the base face has no cutting edges), and a peripheral surface 122 .

[0088] Referring to FIG. 2, the body portion 114 has an axis of elongation A extending through the center of the body portion 114. E Elongated along elongation axis A E is the forward direction D from the second cutting portion 112 toward the first cutting portion 110. F , and forward direction D F and the opposite direction D R Define the following.

[0089] Referring to the remainder of the drawing, the first central axis A C1 (vertical axis) is the extension axis A E , and is defined as extending through the center of the parting insert 100, through the base surface 120 and the rake face 118, and as shown in FIG. 5C, in an upward direction D U and downward D D Define the following.

[0090] Second central axis A C2 is the extension axis A E and the first central axis A C1 and a second central axis A that is perpendicular to both the first and second axes and extends through the center of the parting insert 100. C2 is the first lateral direction D S1 and the first lateral direction D S1 and a second lateral direction D opposite to S2 Define the following.

[0091] The parting insert 100 has an elongation axis A E The insert has an insert length IL that can be measured parallel to the axis of rotation.

[0092] For the sake of brevity, some of the following description will be given assuming that the parting insert 100 is aligned with the first central axis A C1 Since the parting insert 100 is rotationally symmetrical about the center of gravity, it may be performed on only a portion of the parting insert 100. It should be understood that such features may also be present on the opposite end of the parting insert 100.

[0093] The outer peripheral surface 122 includes a front minor surface 122A in the first cutting portion 110, a rear minor surface 122B located in the second cutting portion 112, a left minor surface 122C, and a right minor surface 122D.

[0094] The first cutting portion 110 includes a first minor rake surface 110A on the rake face 118. The first minor rake surface 110A includes a chip former formation 124 in the form of a single recess.

[0095] The first cutting portion 110 further comprises a first front minor rake face 110B at the front minor face 122A, a first left minor rake face 110C at the left minor face 122C, and a first right minor flank face 110D at the right minor face 122D. Notably, the illustrated (inwardly sloping) preferred minor flank face does not extend to the base face 120. However, a minor flank face extending to the base face 120 is also feasible. As shown in the preferred embodiment, the minor flank face extends a height H of less than one-third of the parting insert 100.

[0096] The first cutting edge 102 is formed at the intersection of the first front sub-face 110A with the first front sub-face 110B, the first left sub-face HOC, and the first right sub-face 110D.

[0097] The portion of the cutting edge 102 is described above with reference to FIG.

[0098] The first cutting portion 110 has an elongation axis A E The first cutting length L that can be measured parallel to C1Similarly, the second cutting portion 112 has a second cutting portion length L C2 It may comprise:

[0099] Rearward of the cutting edge, in a plan view of the rake face (22), at least a portion of the insert body adjacent the rake face is recessed from the cutting width defined by the cutting edge (see FIG. 2C), similar to the front (24) and lateral faces (78, 80) of US 11,278,968. In other words, said portion is thinner than the cutting width (i.e., extends laterally inward on both sides), so that the insert body does not contact the slit in the workpiece formed by the cutting edge.

[0100] The first cutting edge 102 has a first cutting width CW1 and the second cutting edge 104 has a second cutting width CW2.

[0101] Elongated body portion 114 has a body width BW and a body length BL.

[0102] The insert length IL is the sum of the body length BL and the first cutting part length L C1 and the second cutting portion length L C2 (IL=BL+L C1 +L C2 ).

[0103] The parting insert 100 can enter the slit only until the width of the insert body becomes wider (considering that the body width BW is designed to be as wide as possible even at the thinnest part of the body width BW to avoid unnecessary weakening of the structure), so that the first cutting portion 100 is the effective cutting portion (i.e., the parting insert 100 is moved in the forward direction D relatively toward the workpiece). F ), the depth of cut DC is substantially equal to a first effective length OL1 measurable from the forward-most point of the first cutting edge 102 to the transition region 116 between the elongated body portion 114 and the second cutting portion 112.

[0104] The parting insert 100 has the same cutting depth DC after the insert is replaced for the second cutting portion 112, ie, the second effective length OL2.

[0105] The insert may have a first insert ratio R1, defined as the ratio of cutting depth to first cutting width (R1=DC / CW1). Thus, for an insert having a cutting depth DC=12 mm and a first cutting width CW1=1 mm, the first insert ratio is 12. Preferably, the first insert ratio R1 for a cutting insert according to the present subject matter satisfies the condition: 6≦R1≦16, more preferably 10≦R1≦14, and most preferably 11≦R1≦13.

[0106] The insert may have a second insert ratio R2 defined as the ratio of the insert length IL to the insert height H (R2=IL / H). Thus, for an insert having a length IL=14 mm and a height H=4 mm, the second insert ratio is 3.5. Preferably, the second insert ratio R2 for cutting inserts according to the present subject matter satisfies the condition: 1≦R2≦4.5, more preferably 2.5≦R2≦3.8, and most preferably 3≦R2≦3.6.

Claims

1. A two-cutting edge parting insert, comprising: a first cutting portion; a second cutting portion; an elongated body portion connecting the first cutting portion and the second cutting portion; The scooping surface and a base surface located opposite the rake surface; an outer peripheral surface connecting the rake face and the base surface; The outer circumferential surface is a front minor surface of the first cutting portion; a rear minor surface located in the second cutting portion and opposite the front minor surface; a left minor surface connecting the front minor surface and the rear minor surface and located on one side of the parting insert; a right minor surface connecting the front minor surface and the rear minor surface and positioned opposite the left minor surface, the body portion is elongated along an elongation axis extending through a center of the body portion; The elongation axis (A Ｅ ) is the forward direction (D) from the second cutting portion toward the first cutting portion Ｆ ), and a rearward direction (D Ｒ ) is defined, The parting insert has an elongated axis (A Ｅ ) an insert length (IL) measured along the The parting insert has an elongated axis (A Ｅ ) having a height (H) measured perpendicular to the The first central axis (A Ｃ１ ) is defined as being perpendicular to the elongation axis, extending through the center of the parting insert, and extending through the base surface and the rake surface, and the first central axis (A Ｃ１ ) is the upward direction (D Ｕ ) and a downward direction (D Ｄ ) is defined, The second central axis (A Ｃ２ ) is the extension axis (A Ｅ ) and the first central axis (A Ｃ１ ) and extending through the center of the parting insert, and the second central axis (A Ｃ２ ) in the first lateral direction (D Ｓ１ ) and the first lateral direction (D Ｓ１ ) and a second lateral direction (D Ｓ２ ) is defined, The first cutting portion is a first minor rake surface on the rake face; a first front minor rake face on the front minor surface; a first left minor rake face on the left minor surface; a first right minor rake face on the right minor surface; a first cutting edge formed at an intersection line between the first front sub-rake surface and each of the first front sub-rake surface, the first left sub-rake surface, and the first right sub-rake surface; The first cutting edge is a first front minor cutting edge extending along an intersection line between the first minor cutting surface and the first front minor cutting surface; a first left minor cutting edge extending along an intersection line between the first minor cutting surface and the first left minor cutting surface; a first right minor cutting edge extending along an intersection line between the first minor cutting surface and the first right minor cutting surface; a first left corner formed at an intersection line between the first front minor cutting edge and the first left minor cutting edge; a first right corner formed at an intersection line between the first front minor cutting edge and the first right minor cutting edge, The second cutting portion is a second sub-rake surface on the rake surface; a second front sub-rake surface on the rear sub-surface; a second left minor rake face on the right minor face; a second right minor rake face on the left minor face; a second cutting edge formed at an intersection line between the second front sub-rake surface and each of the second front sub-rake surface, the second left sub-rake surface, and the second right sub-rake surface; The second cutting edge is a second front minor cutting edge extending along an intersection line between the second minor cutting surface and the second front minor cutting surface; a second left minor cutting edge extending along an intersection line between the second minor cutting surface and the second left minor cutting surface; a second right minor cutting edge extending along an intersection line between the second minor cutting surface and the second right minor cutting surface; a second left corner formed at an intersection line between the second frontmost minor cutting edge and the second left minor cutting edge; a second right corner formed at an intersection line between the second frontmost minor cutting edge and the second right minor cutting edge, Horizontal axis (A Ｌ ) extends through the frontmost portion of the first cutting edge, and the horizontal axis (A Ｌ ) is the second central axis (A Ｃ２ ) and extends parallel to the first lateral direction (DS1) and the first lateral direction (D Ｓ１ ) and a second lateral direction (D Ｓ２ ) is defined, the first cutting edge has a first width of cut (CW1) measurable parallel to the transverse axis from the first left corner to the first right corner; the second cutting edge has a second width of cut (CW2) measurable parallel to the transverse axis from the second left corner to the second right corner; the elongate body portion has a body width (BW) measurable parallel to the transverse axis and a body length (BL) measurable parallel to the elongation axis; The body width (BW) is smaller than both the first cutting width (CW1) and the second cutting width (CW2); Condition: 0.55 mm≦BW≦0.95 mm is satisfied; The body length (BL) is A parting insert that satisfies the condition: 2 mm≦BL≦14 mm.

2. The parting insert according to claim 1, wherein the body width (BW) satisfies the condition: 0.65 mm≦BW≦0.95 mm.

3. The parting insert according to claim 2, wherein the body width (BW) satisfies the condition: 0.75 mm≦BW≦0.95 mm.

4. The parting insert according to claim 1, wherein the body width (BW) satisfies the condition: 0.55 mm≦BW≦0.85 mm.

5. The parting insert according to claim 1, wherein the body length (BL) satisfies the condition: 6 mm≦BL≦14 mm.

6. The parting insert according to claim 5, wherein the body length (BL) satisfies the condition: 8 mm≦BL≦14 mm.

7. The parting insert according to claim 1, wherein the body length (BL) satisfies the condition: 2 mm≦BL≦12 mm.

8. 8. The parting insert according to claim 7, wherein the body length (BL) satisfies the condition: 6 mm≦BL≦11 mm.

9. The first cutting width (CW1) and the second cutting width (CW2) are The parting insert according to any one of claims 1 to 8, satisfying the condition: 0.75 mm ≦ CW1, CW2 ≦ 1.1 mm.

10. The first cutting width (CW1) and the second cutting width (CW2) are The parting insert according to claim 9, wherein the condition: 0.76 mm≦CW1, CW2≦0.84 mm is satisfied.

11. The first cutting width (CW1) and the second cutting width (CW2) are The parting insert according to claim 9, wherein the condition: 0.9 mm≦CW1, CW2≦1.1 mm is satisfied.

12. The first cutting width (CW1) and the second cutting width (CW2) are The parting insert according to claim 11, satisfying the condition: 0.96 mm≦CW1, CW2≦1.04 mm.

13. The parting insert has an elongated axis (A Ｅ 13. The parting insert according to claim 1, having a first effective length (OL1) measurable parallel to a line of intersection of the body portion and the second cutting portion from a foremost point of the first cutting edge to a line of intersection of the body portion and the second cutting portion, wherein the condition: 5 mm≦OL1≦15 mm is satisfied.

14. The parting insert according to claim 13, wherein the first effective length (OL1) satisfies the condition: 9 mm≦OL1≦13.5 mm.

15. The parting insert according to claim 14, wherein the first effective length (OL1) satisfies the condition: 11 mm≦OL1≦12.5 mm.

16. The parting insert according to any one of claims 1 to 15, wherein the parting insert has no grinding surface.

17. The parting insert according to any one of claims 1 to 16, wherein the height (H) of the body portion satisfies the condition: 3.5 mm≦H≦4.5 mm.

18. The first cutting portion has a first cutting portion length (L Ｃ１ ) further comprising: The first cutting portion length (L Ｃ１ ) is the extension axis (A Ｅ ) and can be measured parallel to the condition: 1.25 mm≦L Ｃ１ The parting insert according to any one of claims 1 to 17, wherein the parting insert satisfies ≦1.5 mm.

19. The parting insert according to any one of claims 1 to 18, wherein a first insert ratio (R1) is defined as a ratio of a cutting depth (DC) to the first cutting width (CW1) (R1 = DC / CW1), and satisfies the condition: 6 ≦ R1 ≦ 16.

20. A second insert ratio (R2) is defined as a ratio of the insert length (IL) to the insert height (H) (R2 = IL / H), and satisfies the condition: 1 ≦ R2 ≦ 4.

5. The parting insert according to any one of claims 1 to 19.

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