Indexable parting blade with circuitous coolant channels

Abstract

To provide an indexable parting blade.SOLUTION: An indexable parting blade has: opposite blade first and second sides; a blade peripheral edge; a central index axis; and at least first, second and third insert pockets located along the blade peripheral edge. The parting blade also has first, second and third coolant channels, each forming a coolant path from a corresponding inlet to a corresponding one of the insert pockets. Each coolant channel includes: a rake outlet opening out to a rake side of its corresponding insert pocket; and a relief outlet opening out to a relief side of that same insert pocket. The inlet corresponding to a given coolant channel is located farther from that coolant channel's insert pocket than at least one of the inlet corresponding to a different coolant channel, and the central index axis.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an indexable parting blade (hereinafter also referred to as "blade"), a blade holder (hereinafter also referred to as "holder"), and a tool assembly including both the blade and the holder, all configured for parting. More specifically, the present invention relates to an indexable parting blade having multiple coolant passages, each configured to supply coolant to a corresponding insert pocket. [Background technology]

[0002] A parting blade, as the name suggests, may be considered to have a "blade" shape, meaning a thin knife or plate shape that penetrates a relatively large depth into a metal workpiece in a parting operation. Stated differently, the thickness of the blade, measured perpendicular to the first and second sides, is the blade's overwhelming smallest dimension.

[0003] Most conventional parting blades are elongated.

[0004] It will be appreciated that components configured for parting off may be used for relatively shallow groove cutting operations, although in some cases the reverse may not be true.

[0005] Because it is difficult to supply coolant to cutting inserts located within thin slits (in the workpiece being parted off), it is common to provide internal coolant passages in the parting blade.

[0006] The present invention is an improvement over Applicant's previous invention, described in US2019 / 0240741. The present invention is not limited to the four-way indexable parting blades shown in Figures 18B-20B, but is certainly applicable to at least three-way indexable blades, for example, those shown in Figures 21A-23D. To discuss the coolant passage difficulties addressed in the present application with reference to the embodiment of Figures 18B-20B, a four-way indexable parting blade will be described.

[0007] With reference to this embodiment, a rotationally symmetric parting blade and a holder therefor will be described. The blade has a single coolant passage per insert pocket. Each coolant passage has a blade inlet opening and a blade outlet opening.

[0008] The blade entry opening is preferably not located on (or stated differently from) the central indexable axis to allow for greater cutting depth for indexable parting blades. It will be understood that although parting blades visually appear similar to rotary fluting discs, rotary fluting discs use all of the cutting inserts in a single operation and are not indexed in a holder to position new insert pockets for machining.

[0009] In particular, the blade exit opening is the only exit opening provided in the insert seat and is directed above the rake face of the cutting insert held by the insert seat.

[0010] Although it is known to provide two blade exit openings per insert seat in an elongated parting blade, due to the four-way rotational symmetry of the parting blade, it has been found that only a single blade exit opening is feasible (in some cases, a single blade exit opening oriented above the rake face is the preferred embodiment described in commonly assigned US2013 / 0236253). It should be noted that more than two exit openings were not presented due to several difficulties overcome in the present invention.

[0011] One such difficulty is that when there are several insert pockets and the blade inlet opening associated with each pocket is located in a non-centered position (or at least in a position where the blade inlet opening is not in the same section of the blade as the blade exit opening or is not adjacent to the blade exit opening), the direct path of one passage from the blade inlet opening to the blade exit opening is obstructed by another passage having a similar path.

[0012] Another difficulty is the lack of space required for additional coolant passages.

[0013] For purposes of clarity, it should be noted that the present invention relates to coolant passages for indexable parting blades, and that features relating to other components and all non-coolant related features disclosed in US2019 / 0240741 are incorporated herein by reference.

[0014] It should be noted that various coolant passages are described in other publications.

[0015] US Pat. No. 10,661,352 discloses a parting blade having three coolant passages for a single insert pocket.

[0016] In particular, USP 10,661,352 is an elongated parting blade (the most common shape of parting blade today) that does not have the same spatial constraints as the three-way or four-way indexable blades described above with respect to US 2019 / 0240741 due to its larger structure and fewer insert pockets, and therefore each insert pocket can easily have two (or even three) blade exit openings associated with it.

[0017] It will be appreciated that the problems overcome by the present invention arise particularly in parting blades having a relatively large number of insert pockets for a given size blade. As shown, the parting blade disclosed in U.S. Pat. No. 10,661,352 does not have significant space constraints on the number of coolant passages and the elongated shape of the parting blade (since there is no difficulty with passages crossing other passages in a direct path, as in U.S. Pat. No. 2019 / 0240741).

[0018] Yet another aspect of the invention relates to advantageous cross-sectional shapes developed for coolant passages produced by additive manufacturing, which shapes are particularly advantageous for indexable parting blades.

[0019] It should be noted that while USP 10,661,352 describes for most embodiments circuit-like cross-sectional passages that can be produced by conventional manufacturing methods, other cross-sections such as polygonal or elliptical are possible with additive manufacturing methods.

[0020] Similarly, DE202018105949 shows a design exhibiting an elliptical cross section.

[0021] It is also known in the art of additive manufacturing to create coolant passages that have a teardrop shape (i.e., a coolant passage with a circular lower edge and an upper edge that has an inverted V-shape on the upper side, the purpose of which is to reduce collapse of the upper side during manufacturing). Summary of the Invention [Problem to be solved by the invention]

[0022] It is an object of the present invention to provide a new and improved indexable parting blade. [Means for solving the problem]

[0023] According to a first aspect of the present invention, there is provided an indexable parting blade, the indexable parting blade comprising: an opposing blade first side and a blade second side; a blade outer peripheral edge connecting the blade first side and the blade second side; a central cutting edge replacement axis extending through the center of the blade first side and the blade second side; a first insert pocket, a second insert pocket, and a third insert pocket located along the outer periphery of the blade; a first coolant passage, a second coolant passage, and a third coolant passage; the first coolant passage includes a first inlet, at least one first outlet opening into the first insert pocket, and a first passage portion extending between the first inlet and the at least one first outlet; the second coolant passage includes a second inlet, at least one second outlet opening into the second insert pocket, and a second passage portion extending between the second inlet and the at least one second outlet; the third coolant passage includes a third inlet, at least one third outlet opening into the third insert pocket, and a third passage portion extending between the third inlet and the at least one third outlet; the at least one first outlet comprises a first rake face outlet opening to a rake face side of the first insert pocket and a first flank face outlet opening to a flank side of the first insert pocket; The first inlet is located farther from the farthest point of the first insert pocket than at least one of (a) the second inlet and (b) the central cutting edge change axis.

[0024] The present invention allows for two outlets in a single insert pocket for the first time, despite the space constraints of being indexable on at least three sides. This also allows for a favorable large parting depth, since the first inlet is relatively far from at least one first outlet.

[0025] For purposes of clarity, it is noted that the other embodiments listed below are advantageous, even without being limited to at least three-way indexability (or stated differently, preferably at least three insert pockets equally spaced about a central index axis), although it will be understood that the following embodiments may advantageously be more than three-way indexable (i.e., three insert pockets).

[0026] One approach is to position the first inlet farther from the farthest point of the first insert pocket than the second inlet. Thus, a desirable relatively large parting depth can be achieved even though the second inlet and associated second coolant passage block a direct path to at least one of the first coolant passage's two outlets. In other words, the second coolant passage blocks a direct path from the first inlet to at least one of the at least one first outlet.

[0027] Alternatively or additionally, the first inlet can be positioned further from the farthest point of the first insert pocket than a central cutting edge change axis extending through the center of the blade first side and the blade second side, again allowing a relatively large parting depth to be achieved.

[0028] It will be appreciated that it would be very difficult or impractical to make a coolant passage have multiple turns (which would then require plugging of drilled entry holes, etc.) using conventional machining methods. The present invention utilizes a nested coolant passage configuration.

[0029] In particular, the parallel or essentially parallel running of multiple coolant passages under the base jaw of the insert pocket, where the main machining forces are applied, poses a risk of excessively weakening the blade structure, but inspections have shown that the exemplary design is strong enough for parting-off operations.

[0030] According to a second aspect of the present invention, there is provided an indexable parting blade, the indexable parting blade comprising: opposing first and second blade sides; a blade outer peripheral edge connecting the first and second blade sides; first and second insert pockets located along the blade outer peripheral edge; and first and second coolant passages, the first coolant passage comprising a first inlet and at least one first outlet opening into the first insert pocket and a first passage portion extending from the first inlet to the at least one first outlet opening; and the second coolant passage comprising a second inlet and at least one first outlet opening into the second insert pocket. a second outlet; and a second passageway segment extending from the second inlet to the at least one second outlet opening, the passageway path of the first passageway segment having a first position proximate the first inlet where the passageway path extends in a first direction toward the first insert pocket than away from the first insert pocket, a second position farther along the passageway path from the first inlet than at the first position where the passageway path extends in a second direction further away from the first insert pocket than towards the first insert pocket, and a third position farther along the passageway path from the first inlet than at the second position where the passageway path extends in a third direction toward the first insert pocket than away from the first insert pocket.

[0031] It will be appreciated from the drawings that, in the limited available area, sharp turns are required for the coolant passages to bypass other obstructing coolant passages and to direct them to the relevant cutting area (i.e., the area of ​​the workpiece or cutting insert).

[0032] It will be appreciated that prior known coolant passages typically have turns of at most slightly more than 90°, as it is known that sharper turns cause more severe pressure drops and are therefore disadvantageous and should be avoided.

[0033] It will be understood that the sharp turn defined in the second or third embodiment can alternatively be defined as a U-turn. Drawing an imaginary line along the two arms of the U-shape at the final turn leading to the third position, the sharp turn forms an acute angle α that satisfies the condition: α<80°, preferably α<70°, more preferably α<60°, and even more preferably α<50° (the latter value α<50° is desirable due to space limitations rather than coolant flow, as it leaves the most compact configuration). However, to reduce pressure drop, α<20° and more preferably α<30° are more preferred.

[0034] However, it was determined that such a pressure drop still delivered more coolant to the cutting insert or workpiece than would be possible without a complete coolant outlet. Additionally, to offset the pressure drop, an enlarged cross section was developed in the sharp turn, as described below.

[0035] As noted above, it is more difficult to produce sharp turns with conventional manufacturing methods (e.g., because multiple plugging operations such as welding are also required) (indeed, the turn of the present invention may be considered two closely spaced sharp turns).

[0036] While the illustrated example shows a sharp turn below the insert pocket (i.e., associated with the secondary passages supplying coolant to the flank side of the pocket), the passages could alternatively be counter-nested sharp turns (not shown) and originate on the rake side of the pocket. In other words, the passages could extend from the inlets in a counter-clockwise direction rather than the clockwise direction illustrated (still bypassing (in a rotational sense) the adjacent coolant inlets by subsequently extending between them and the blade periphery before reaching the insert pocket). While the preferred example shown has a sharp turn on the flank side of the insert pocket, which is more relevant to cutting forces, it is preferable to have a more effective coolant supply on the rake side of the insert pocket, and therefore this configuration is preferred. However, a counter-nested configuration is also feasible.

[0037] Alternatively, the invention may be expressed in terms of the number of sharp turns that the path takes.

[0038] According to a third aspect of the present invention, there is provided an indexable parting blade, the indexable parting blade comprising: opposing first and second blade sides; a blade outer peripheral edge connecting the first and second blade sides; first and second insert pockets located along the blade outer peripheral edge; and first and second coolant passages, the first coolant passage comprising a first inlet and at least one first outlet opening into the first insert pocket and a first passage portion extending from the first inlet to the at least one first outlet opening; and the second coolant passage comprising a second inlet and at least one second outlet opening into the second insert pocket and a first passage portion extending from the second inlet to the at least one first outlet opening. and a second passageway portion extending to a second outlet opening, the passageway path of the first passageway portion comprising a first significant turn portion forming a passageway first angle α1 satisfying the condition: 25°<α1<155°, a second significant turn portion forming a passageway second angle α2 satisfying the condition: 25°<α2<155°, a third significant turn portion forming a passageway third angle α3 satisfying the condition: 25°<α3<155°, and a fourth significant turn portion forming a passageway fourth angle α4 satisfying the condition: 25°<α4<155°, wherein along the passageway path the second significant turn portion is downstream from the first significant turn portion, the third significant turn portion is downstream from the second significant turn portion, and the fourth significant turn portion is downstream from the third significant turn portion.

[0039] It will be appreciated from the above that in this embodiment the final "sharp turn" or "U-turn" may alternatively be defined as two adjacent sharp turns (a "sharp turn" in this application is defined as forming an angle greater than 25°, preferably greater than 45° and less than 155°).

[0040] There may be continuous curved connections between adjacent turns.

[0041] Unlike the large turns shown in the prior art, the sharp turns may have a very small radius of curvature R of less than 5 mm (R<5 mm), preferably R<3.5 mm and most preferably R<2 mm. It will be appreciated that these preferences are only beneficial due to the need to address space constraints, and not from a pressure drop perspective.

[0042] The angle α1 of the passage section first preferably satisfies the condition: 70°<α1<130°, preferably 80°<α1<120°, more preferably 90°<α1<110°.

[0043] The angle α2 of the passage section second preferably satisfies the condition: 110°<α2<155°, preferably 125°<α2<150°, more preferably 130°<α2<150°.

[0044] The angle α3 of the passage section third preferably satisfies the condition: 90°<α3<155°, preferably 105°<α3<140°, more preferably 115°<α3<135°.

[0045] The fourth passage angle α4 preferably satisfies the condition: 70°<α4<130°, preferably 80°<α4<120°, more preferably 90°<α4<110°.

[0046] As shown in FIG. 6 of US2019 / 0240741, the total cutting force FC on the cutting insert, and therefore the insert pocket that holds the cutting insert, is directed downward rather than rearward.

[0047] As can be seen, one way to achieve coolant supply to both sides of the insert pocket for space-limited indexable parting blades is to provide multiple, tightly stacked coolant passages even below the insert pocket where the force is directed.

[0048] Therefore, according to a fourth aspect of the present invention, there is provided an indexable parting blade, the indexable parting blade comprising: opposing first and second blade sides; a blade outer peripheral edge connecting the first and second blade sides; and a first insert pocket and a second insert pocket located along the blade outer peripheral edge, the first insert pocket being located along the blade outer peripheral edge and including a base jaw, a second jaw opposite the base jaw, and a connecting portion between the base jaw and the second jaw. a slot end, wherein the basic jaw defines a basic plane and has a forward-most point distal to the slot end, the basic plane defining an aft direction defined from the forward-most point toward the blade, a forward direction opposite the aft direction, an upward direction perpendicular to the forward and aft directions and away from the basic jaw and the blade, and a downward direction opposite the upward direction, a force angle range θ having an apex at the forward-most point and defined between the downward direction and the aft direction, satisfying the condition: 50° > θ > 10°, and an imaginary diagonal line L1 extending from the forward-most point within the force angle range θ intersects at least two coolant passages.

[0049] As will be appreciated, due to the above concerns of weakening the already thin parting blade, the alternative definition not in terms of force angle but in terms of the location of the multiple coolant paths relative to the insert pocket is similarly counterintuitive (becoming even more counterintuitive as the proximity to the insert pocket increases).

[0050] Thus, according to a fifth aspect of the present invention, there is provided an indexable parting blade, the indexable parting blade comprising: opposing first and second blade sides; a blade outer circumferential edge connecting the first and second blade sides; and first and second insert pockets located along the blade outer circumferential edge, the first insert pocket being located along the blade outer circumferential edge and including a base jaw; a second jaw opposite the base jaw; and a slot connecting the base jaw and the second jaw. and a slot end, wherein the basic jaw defines a basic plane and has a forward-most point distal to the slot end, the basic plane defining an aft direction defined from the forward-most point towards the blade, a forward direction opposite the aft direction, an upward direction perpendicular to the forward and aft directions and away from the basic jaw and the blade, and a downward direction opposite the upward direction, the first insert pocket having a rearward-most point, and a region comprising at least two different coolant passages defined strictly in the downward direction between a first imaginary downward line L2 extending from the rearward-most point and forward of the first imaginary downward line L2.

[0051] During development of the indexable parting blade of the present invention, advantageous coolant passage cross-sections were developed.

[0052] According to a sixth aspect of the present invention, there is provided an indexable parting blade, the indexable parting blade comprising: a blade first side and a blade second side opposite each other; a blade outer peripheral edge connecting the blade first side and the blade second side; a first insert pocket and a second insert pocket located along the blade outer peripheral edge; and a first coolant passage, the first coolant passage comprising: a first inlet, at least one first outlet opening into the first insert pocket, and a passage portion extending from the first inlet to the at least one first outlet opening, at least a portion of the passage portion having a cross-sectional shape, the cross-sectional shape being the blade includes opposing first and second side edges extending along the first and second sides of the blade; a first straight upper edge extending from the first side edge at a first obtuse angle β1 within the passage portion; a second straight upper edge extending from the second side edge at a second obtuse angle β2 within the passage portion; a first straight lower edge extending from the opposite side of the first side edge to the first upper edge at a third obtuse angle β3 within the passage portion; and a second straight lower edge extending from the opposite side of the second side edge to the second upper edge at a fourth obtuse angle β4 within the passage portion, the first upper edge and the second upper edge joining at an upper corner edge and the first lower edge and the second lower edge joining at a lower corner edge.

[0053] While teardrop-shaped coolant passages, i.e., coolant passages with converging straight upper edges, are known to reduce collapse of the upper sides of the coolant passages, the shape of the present invention allows for the same effect, even in the case of multiple coolant passages that do not have a pronounced upper edge due to their large turning path. The passages may vary in various portions of the passage, but it is preferred that the cross-sectional shape remains uniform, at least over the majority of the passage, to avoid pressure drop to the greatest extent possible.

[0054] In the above publication, elliptical shapes were also used. While such shapes would likely result in a larger cross-sectional area than the shapes defined above and one might think that an elliptical shape would result in better coolant flow, it has been found that straight upper and lower edges may be even more beneficial, as it has been found that the surface finish of the passage is improved over the curved upper or lower edges, so that straight edges were preferred even when the cross-sectional area was reduced (compared to an elliptical shape).

[0055] The cross-sectional shape preferences are as follows:

[0056] The first and second side edges extend parallel to the blade first and second sides.

[0057] The first side edge and the second side edge are each longer than the first top edge and the second top edge, respectively.

[0058] The first and second side edges are each longer than the first and second bottom edges, respectively.

[0059] The cross-sectional shape is elongated in a direction parallel to the blade first side and the blade second side.

[0060] The cross-sectional shape is mirror symmetric about a first mid-plane, the first mid-plane being perpendicular to and extending through the midpoint between the first and second side edges.

[0061] The cross-sectional shape is mirror symmetric about a second mid-plane, the second mid-plane being parallel to and extending through the middle of the first and second side edges.

[0062] The passageway portion has a defined cross-sectional shape along a majority of the passageway portion.

[0063] The second coolant passage includes a second inlet, at least one second outlet opening into the second insert pocket, and a second passage portion extending between the second inlet and the at least one second outlet, the second passage portion having a defined cross-sectional shape along a majority of the second passage portion.

[0064] The third coolant passage includes a third inlet, at least one third outlet opening into the third insert pocket, and a third passage portion extending between the third inlet and the at least one third outlet, the third passage portion having a defined cross-sectional shape along a majority of the third passage portion.

[0065] In at least one first outlet, the cross-sectional profile of the first outlet includes first and second side edges that are shorter than previous portions of the passageway section.

[0066] For at least one first outlet, the cross-sectional profile of the first outlet includes first and second side edges that are shorter than the first and second top edge portions.

[0067] For at least one first outlet, the cross-sectional profile of the first outlet includes first and second side edges that are shorter than the first and second bottom edge portions.

[0068] In particular, the outlet preference reduces coolant flow even more than an elliptical shape, but is still desirable for structural strength purposes.

[0069] The upper and lower corner edges are concave.

[0070] Further related developments were made to indexable parting blades in terms of inlet geometry orientation: all inlets were oriented similarly to simplify manufacturing and allow printing without considering a specific indexable orientation.

[0071] Thus, according to a seventh aspect of the present invention, there is provided an indexable parting blade comprising: opposing blade first and second sides; a blade outer circumferential edge connecting the blade first and second sides; first, second and third insert pockets located along the blade outer circumferential edge; and first, second and third coolant passages, the first coolant passage having a first inlet and at least one first outlet opening into the first insert pocket, and a first passage extending between the first inlet and the at least one first outlet. the second coolant passage comprises a second inlet, at least one second outlet opening into the second insert pocket, and a second passage portion extending between the second inlet and the at least one second outlet; the third coolant passage comprises a third inlet, at least one third outlet opening into the third insert pocket, and a third passage portion extending between the third inlet and the at least one third outlet; the first inlet, second inlet, and third inlet open into one or both of the blade first side and the blade second side, and each inlet comprises a pair of converging straight upper inlet edges, all of which are oriented in the same direction.

[0072] The other openings in the first and second sides of the blade were preferably, but not limited to, circular cross-sectional shapes as shown, but no such considerations were required for the inlets since they did not require threads extending through them.

[0073] All of the inlets can have a standard teardrop shape, but a polygon with four straight edges (i.e., a square rotated 45°) was preferred for four-way indexable blades. Similarly, a triangular shape (preferably an equilateral triangle) was preferred for three-way indexable blades.

[0074] Referring again to the sharp turns described in the second and third aspects, an advantageous method has been developed to compensate for the restriction to fluid flow.

[0075] That is, according to an eighth aspect of the present invention, there is provided a parting blade comprising: opposing blade first and second sides; a blade outer peripheral edge connecting the first and second sides; at least one first insert pocket; and a first coolant passage, the first coolant passage comprising a first inlet, at least one first outlet opening into the first insert pocket, and a first passage portion extending between the first inlet and the at least one first outlet, the first passage portion comprising a curved turn portion preceded by a leading passage portion and followed by a trailing passage portion, the turn portion cross-sectional area measured perpendicular to the coolant passage through the curved turn portion being greater than the leading passage cross-sectional area measured perpendicular to the coolant passage through the leading passage portion.

[0076] Thus, the enlarged cross section in the curved section compensates for the loss in the sharp turn.

[0077] Preferably, the turn cross-sectional area may be greater than the trailing passage cross-sectional area measured perpendicular to the coolant passage through the trailing passage.

[0078] It will be appreciated that generally, the present invention is directed to parting blades having a single active insert pocket during a machining operation, and not to rotary tools that use multiple cutting inserts during a given operation.

[0079] According to a ninth aspect of the present invention, there is provided an indexable parting blade, the indexable parting blade comprising: an opposing blade first side and a blade second side; a blade outer circumferential edge connecting the blade first side and the blade second side; a central indexable axis (AI) extending through centers of the blade first side and the blade second side; at least first, second, and third insert pockets located along the blade outer circumferential edge; and at least first, second, and third coolant passages. each coolant passage forming a passage path from an associated inlet to a corresponding one of the insert pockets, each coolant passage having a rake face outlet opening onto the rake face side of the corresponding insert pocket, a flank face outlet opening into the corresponding insert pocket, and a passage portion connecting the associated inlet to the rake face outlet and the flank face outlet, wherein in a cross section of the parting blade taken between the first side and the second side, an imaginary radial line (LR) extending from a central axis (AI) to any portion of the blade outer periphery intersects at least two of the coolant passages.

[0080] Thus, according to a tenth aspect of the present invention there is provided a tool assembly comprising an indexable parting blade according to any one of the previous aspects and a blade holder configured to hold the parting blade such that only one of the insert pockets of the parting blade is positioned for effective use.

[0081] The blade holder may be of any of the known characteristics for prior art blade holders, most preferably of the type described in US2019 / 0240741.

[0082] Although the main inventive features of the present invention have been described above in separate embodiments, it will be understood that any combination of the main inventive features (as illustrated in the drawings) is also possible.

[0083] To summarize the main features, a parting blade according to the present invention may have one or more of: (a) a first inlet located relatively far from the farthest point of the insert pocket; (b) a sharp turn; (c) two or more coolant passages within the cutting force path or alternatively below the insert pocket; (d) at least one, and preferably all, of the passages have a cross-sectional shape with straight, converging upper and lower edges; and (e) all inlets have straight, converging upper edges oriented in the same direction.

[0084] Preferred features for all of the above aspects are now described.

[0085] It will be appreciated that the present invention has many more applications, including, but not limited to, non-elongated, regular shapes, such as triangles, squares, etc. In other words, the parting blade may be indexable about a central index axis extending through the centers of the first and second sides of the parting blade. However, it will be appreciated that the present invention is applicable to any parting blade that does not have sufficient space for the desired coolant passages. For example, one obvious case in which the present invention may be beneficial for an elongated, rectangular (standard shaped) parting blade is when the parting blade has four insert pockets, thus requiring a relatively large number of coolant passages.

[0086] Similarly, it will be appreciated that the present invention is more applicable to three-way (i.e., having three insert pockets) indexable blades than two-way indexable blades, as it is more applicable in blades with limited space. This is for the same reason that a blade with three insert pockets requires more space for coolant passages than a similarly sized blade with two insert pockets. Similarly, the present invention is more advantageous in four-way indexable blades than three-way indexable blades, and so on.

[0087] To be indexable, the insert pockets are preferably equally angularly spaced around the outer periphery of the parting blade.

[0088] It will be appreciated that the present invention is more applicable to blades with limited space, so that for extremely large blades, such invention is less necessary. However, simply increasing the size of the blade is problematic because CNC machines are space-limited, and increasing the blade size requires a larger blade holder or a larger overhang, both of which are disadvantages. That said, to provide some quantitative perspective, an imaginary circumscribing circle C in a side view of the blade has a diameter D that satisfies the following conditions: D<90 mm, preferably D<80 mm, more preferably D<70 mm, and most preferably D<60 mm.

[0089] Similarly, sharp turns are particularly applicable within a distance proximate to an associated insert pocket. To provide some perspective, the insert pocket length LP may define the insert pocket from its forward-most point to its rear-most point. From the forward-most point, a second position (where the passageway begins to extend in a second direction away from the first insert pocket rather than toward the first insert pocket) is within a second position length LS that satisfies the condition: LS<3LP, preferably LS<2LP, and most preferably LS<1.5LP. Alternatively, quantitatively defined, the second position length LS may satisfy the condition: LS<15mm, preferably LS<10mm, and most preferably LS<7.5mm.

[0090] Similarly, the restricted space for a coolant passage or coolant passages within a distance close to the associated insert pocket can be defined as follows. From the leading point to the closest contact point of the closest coolant passage, a closest length LC is defined that satisfies the conditions: LS < 3LP, preferably LS < 2LP, and most preferably LS < 1.5LP. Alternatively, quantitatively defined, the closest length LC can satisfy the conditions: LC < 15 mm, preferably LC < 10 mm, and most preferably LC < 7.5 mm.

[0091] The intermediate distance LI from the closest passage to the insert pocket to the adjacent passage can satisfy the following conditions: LI < LP, preferably LI < 0.5LP, and most preferably LI < 0.25LP (the intermediate distance LI is measured along the same line from the leading point to the closest contact point of the closest coolant passage, but starts only on the other side of the closest contact point of the coolant passage and extends to the closest contact point of the adjacent passage). Alternatively, quantitatively defined, the intermediate length LI can satisfy the conditions: LI < 5 mm, preferably LI < 2.5 mm, and most preferably LI < 1.25 mm.

[0092] In the previous paragraphs, various modes (the overall size of the cut-off blade, the proximity of the passage or sharp turn portion to the insert pocket, etc.) have been described to explain the space limitation of the cut-off blade with respect to the coolant passage.

[0093] Yet another way of defining a limited space relates to the indexability of the parting blade. The indexable parting blade according to any one of the embodiments can be divided into imaginary sections S. The sections S are defined as a number equal to the number of insert pockets N in the parting blade (S = N). These sections are defined by specifying imaginary section planes PS passing through the central indexing axis IA at angular intervals equal to 360° / S, with the planes PS equally spaced between the insert pockets. Thus, for example, a square parting blade with four equally spaced insert pockets at each corner is divided into four basic square sections at each corner in side view by two imaginary orthogonal section planes. A further example is a triangular parting blade with three equally spaced insert pockets at each corner, divided into three sections at each corner. Considering a two-way indexable geometry (two insert pockets), such as a conventional elongated parting blade with two equally spaced insert pockets (i.e., located in diagonally opposite pockets), there are two sections. However, in the latter example, a single imaginary sectioning plane between the two insert pockets can be drawn either longitudinally along the blade extension (in a side view of the main surface) or perpendicular to the blade extension. In such cases, the orientation of the imaginary sectioning plane for purposes of the present invention should be selected as the sectioning plane extends closer to the insert pocket than would occur in an alternative orientation. This is because a more restricted section on at least one side of the insert pocket would result, making it more difficult to extend the coolant passages along this side (and therefore more applicable to the present invention). Therefore, in the case of the conventional elongated blade, the imaginary sectioning plane extends parallel to the direction of the blade extension.

[0094] In a preferred embodiment, the inlets of the coolant passages are located in a different section than the outlets of at least one of the coolant passages.

[0095] In a preferred embodiment, the sharp turn (or U-turn) of the coolant passage is located exactly in the same section as at least one outlet of the coolant passage. Alternatively, in a preferred embodiment, the second and third positions of the coolant passage are located exactly in the same section as at least one outlet of the coolant passage. Alternatively, in a preferred embodiment, the significant third and fourth turns of the coolant passage are located exactly in the same section as at least one outlet of the coolant passage.

[0096] In a preferred embodiment, at least two different passages (i.e. passages starting at different inlets) extend alongside each other, as this limits the available area. The extension (LE) of the two essentially parallel portions of the two different passages may be at least 10% of the corresponding length of the blade side BLS (i.e. the length of the blade parallel to the extension of the parallel portions) so as to satisfy the following condition: LE>0.1LS, preferably LE>0.3LS, and most preferably LE>0.5LS.

[0097] In this case, the outermost passage (i.e., the passage closest to the outer periphery of the blade) may turn adjacent to a similar turn of the innermost passage (essentially in the direction of the innermost passage toward the insert pocket having an outlet associated with the innermost passage), and then the outermost passage may turn again and be redirected toward the insert pocket having an outlet passage associated with the outermost passage.

[0098] In a preferred embodiment, the imaginary diagonal line L1 intersects at least two coolant passages within the same section as the associated insert pocket.

[0099] In a preferred embodiment, strictly downward between a first imaginary line L2 extending from the rearmost point and forward from the first imaginary line L2, there is a defined area with at least two different coolant passages.

[0100] It will be understood that the exact force direction on the cutting insert with respect to the force angle range θ will vary with the relative movement of the cutting insert into the workpiece, although the force direction will generally be directed as defined above (i.e., between downward at the forward-most point and toward the rearward direction, and satisfying the condition: 50° > θ > 10°). However, the location of the at least two passages may be more precisely defined within the condition: 40° > θ > 15°, or even more precisely, 30° > θ > 15°.

[0101] It will be appreciated that due to space limitations, the imaginary diagonal line L1 may preferably intersect at least three coolant passages or even at least four coolant passages.

[0102] For passages that intersect either the imaginary oblique line L1 or the first imaginary downward line L2, it is preferred that at least two adjacent passages extend in the same basic direction at the intersection. In other words, it is preferred that at least two adjacent passages extend essentially parallel to each other at the intersection area. In other words, adjacent passages at an intersection can have imaginary extension lines E1, E2 that extend parallel to the coolant path at the intersection and form an angle γ that satisfies the condition: γ<45°, preferably γ<30°, and most preferably γ<15°.

[0103] Note that in the illustrated example there is a central hole shown for purposes other than coolant, but in preferred embodiments the coolant inlet may be formed separately from the central hole (and therefore not open to the inner edge of the central hole), although the reverse is still an option.

[0104] In a preferred embodiment, the coolant passage includes a single initial passage section that then splits into multiple subsequent passage sections. It will be appreciated that a single initial passage section does not require as much space as two parallel passage sections, and therefore this configuration is preferred. Preferably, the initial passage section has a length LCP that is greater than 20% of the overall length LOC from the coolant passage inlet to the nearest outlet (LCP > 0.2 LOC), and more preferably LCP > 0.4 LOC. However, subsequent passage sections preferably include terminal linear sections to properly direct the coolant. Therefore, this splitting preferably is not too close to the outlet. Therefore, it is preferred that LCP < 0.8 LOC, and more preferably LCP < 0.65 LOC.

[0105] More precisely, each of the two subsequent passage portions may extend from the initial passage portion to at least one outlet opening. The at least one first outlet opening may be a rake face outlet opening on the rake face side of the insert pocket and a flank outlet opening on the flank side of the same insert pocket. The subsequent passage portion extending to the rake face outlet may be referred to as a rake face passage portion. The subsequent passage portion extending to the flank face outlet may be referred to as a flank passage portion.

[0106] Any blade shape is possible, but it is preferred that the outer periphery of the blade in a side view (eg, FIG. 3A) of the blade has a straight abutment portion for stable assembly.

[0107] While any insert pocket is feasible, even insert pockets utilizing clamps or screws for thin parting blades generally prefer to use resilient insert pockets that are thinner than the conventional types described above. The resilient insert pockets may have any known configuration. Typically, each insert pocket herein comprises a primary jaw (i.e., a jaw located below the cutting insert, or, in other words, a jaw located on the opposite side of the cutting insert relative to the rake face of the cutting insert) and a secondary jaw. The secondary jaw illustrated in the drawings herein may be defined to extend behind the cutting insert and be located rearward of the primary jaw. Another known configuration is one in which the secondary jaw is located above the primary jaw.

[0108] The blade may include an additional insert pocket, such as a fourth insert pocket located along the outer periphery of the blade, and a fourth coolant passageway forming a passageway from an associated inlet to the fourth insert pocket.

[0109] With respect to the inlet, the inlet preferably comprises an inlet trough which is larger in cross section than the subsequent passage portion.

[0110] The passageway section adjacent the outlet preferably includes a terminal linear section that ensures that the coolant continues its desired path after exiting the blade.

[0111] Each of the features described above with respect to the first coolant passage may also apply to one or more of the other coolant passages, preferably all of the other coolant passages.

[0112] The coolant passages may be similar or identical in each insert pocket.

[0113] As a general note, it should be noted that any turns in a coolant passage may be measured on both sides of the turn (e.g., measured on one side where the angle may be 150° and on the other side where the reflex angle is 210°), but all angles for turns described herein should be measured on the side that is less than 180°.

[0114] For a better understanding of the subject matter of the present application, and to show how it may be carried out in practice, reference will now be made to the accompanying drawings, in which: [Brief explanation of the drawings]

[0115] [Figure 1A] FIG. 1 is a front view of a parting tool assembly according to the present invention; [Figure 1B] FIG. 1B is a top view of the tool assembly of FIG. 1A. [Figure 1C] FIG. 1B is a side view of the tool assembly of FIG. 1A. [Figure 1D] FIG. 1B is a bottom view of the tool assembly of FIG. 1A. [Figure 1E] FIG. 1B is a rear view of the tool assembly of FIG. 1A. [Figure 2A] FIG. 1B is a front view of the blade holder shown in Figure 1A. [Figure 2B] Figure 2A is a top view of the blade holder. [Figure 2C] Figure 2A is a side view of the blade holder. [Figure 2D] Figure 2A is a bottom view of the blade holder. [Figure 2E] Figure 2A is a rear view of the blade holder. [Figure 3A] FIG. 1B is a side view of the parting blade shown in FIG. 1A. [Figure 3B] FIG. 3B is an end view of the parting blade shown in FIG. 3A. [Figure 4] FIG. 3C is an enlarged view of a portion indicated by "IV" in FIG. 3B. [Figure 5] 3B is an enlarged view corresponding to the direction indicated by "V" in FIG. 3A. [Figure 6]6 is a cross-sectional view taken along line VI-VI of FIG. 3B (conventional hash lines are not shown for ease of viewing). [Figure 6B] FIG. 6 shows a portion of a cross section (traditional hash lines are not shown for ease of viewing). [Figure 7] FIG. 7 is an enlarged cross-sectional view taken along line VII-VII in FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0116] 1A-2E, tool assembly 10 includes tool holder 12 and parting blade 14 assembled to tool holder 12 and configured to hold a single cutting insert 16 within active first insert pocket 18A. (Referring to FIG. 3A, in this example, parting blade 14 includes first insert pocket 18A, second insert pocket 18B, third insert pocket 18C, and fourth insert pocket 18D, with first insert pocket 18A being the active insert pocket.)

[0117] The tool holder 12 includes an elongated tool shank 19 having a shank axis AS that defines a front tool direction DTF and a rear tool direction DTR.

[0118] Orthogonal to the front tool direction DTF and the rear tool direction DTR are the top tool direction DTU and the bottom tool direction DTD.

[0119] Orthogonal to the front tool direction DTF, rear tool direction DTR, top tool direction DTU, and bottom tool direction DTD are a first side tool direction DTS1 and a second side tool direction DTS2.

[0120] The tool holder 12 further comprises a tool head 20, which comprises a blade pocket 22 (FIG. 2C) in which the parting blade 14 is fastened via a first screw 24A and a second screw 24B.

[0121] The tool head 20 may also typically include a concave front surface 26. It will be understood that the workpiece (not shown) cannot be parted to a depth greater than that defined by the curvature of the concave front surface 26. However, the concave front surface 26 provides structural support for the thin parting blade 14.

[0122] The blade pocket 22 has a holder outer wall 28 (the abutment surfaces of the holder outer wall 28 are a rear wall portion 28A and a bottom wall portion 28B), and the holder outer wall 28 extends from a pocket side surface 30 of the blade pocket 22 in a first side tool direction DTS1.

[0123] Pocket sides 30 are formed with holder coolant outlets 32 that supply coolant from holder 12 to blade 14 .

[0124] The pocket side 30 may further be formed with an O-ring recess 36 , a threaded sealing bore 34 , and an O-ring (not shown) assembled within the O-ring recess 36 surrounding the holder coolant outlet 32 ​​and the sealing bore 34 .

[0125] Returning to FIG. 1C, a threaded sealing element 38 may extend through the blade 14 and be secured to the sealing bore 34 to prevent coolant exiting the holder 12 from simply passing from the holder coolant outlet 32 ​​through the blade inlet (not shown in FIG. 1C).

[0126] As shown in FIG. 1A, the cutting insert 16 includes a rake face 16B and a leading clearance 16A extending downwardly from the rake face 16B (as well as side clearances, e.g., one side clearance designated 16C is shown in FIG. 1C). Accordingly, the first insert pocket 18A has a rake face side 16D located adjacent to the rake face 16B, or alternatively, located adjacent to or above the rake face 16B. The first insert pocket 18A also has a clearance side 16E located adjacent to the leading clearance 16B, or alternatively, located below the rake face 16A.

[0127] Preferably, the cutting insert 16 is formed with a chip-forming structure 16F (FIG. 1B).

[0128] As shown in FIG. 1B, the cutting width CW of the cutting insert at the cutting edge 40 is greater than the blade width BW of the blade.

[0129] The total cutting force FC is shown schematically by an arrow on the cutting insert 16, and such force is exerted by the workpiece on the insert 16, and therefore the total cutting force FC is essentially continued against the blade 14 in the lower tool direction DTD and the rear tool direction DTR (more in the lower tool direction than the rear tool direction DTR).

[0130] In particular, if the structure comprising the holder coolant outlet 32 ​​extends farther than the front concave surface 26 in one or both of the front tool direction DTF and the top tool direction DTU, the structure reduces the cutting depth capability of the tool assembly 10 because the workpiece is obstructed by the protrusion extending beyond the front concave surface 26. Therefore, it is preferable that the inlet for the blade 14 (e.g., the first inlet 58A shown in FIG. 3A ) be non-centered. Conversely, if the illustrated holder coolant outlet 32 ​​were positioned to supply coolant to the center of the blade (not shown), the overall size of the blade would be smaller than shown, thereby reducing the cutting depth capability of the tool assembly 10. However, it will be understood that this is one option and that some aspects of the present invention are not limited to a non-centered blade inlet. However, a non-centered blade inlet (spaced farther from the active insert pocket) has the advantages discussed above.

[0131] The above description of the tool holder 12 and accessories (screws, seals, etc.) is similar to that described in US2019 / 0240741, and further details are provided in that document, which is incorporated herein by reference.

[0132] 3A and 3B, exemplary features of the present invention will now be described with reference to the exemplary blade 14 shown.

[0133] The parting blade 14 includes a first side surface 42A, a second side surface 42B, and a blade outer peripheral edge portion 44.

[0134] The blade outer peripheral edge 44 includes a first outer peripheral sub-edge 44A, a second outer peripheral sub-edge 44B, a third outer peripheral sub-edge 44C, and a fourth outer peripheral sub-edge 44D that extend between the first insert pocket 18A, the second insert pocket 18B, the third insert pocket 18C, and the fourth insert pocket 18D. The maximum distance between opposing outer peripheral sub-edges defines the length of the blade side BLS.

[0135] Preferably, the peripheral minor edges 44A, 44B, 44C, 44D have straight bearing surfaces (ie, the straight bearing surfaces shown in a side view of the parting blade such as in FIG. 1C).

[0136] The illustrated exemplary parting blade 14 has a regular shape, in this case a basic square. An imaginary circumscribing circle C, shown in FIG. 1C, contacts the outer blade edge 44 of the blade 14, and the imaginary circumscribing circle C has a diameter D.

[0137] The parting blade 14 is rotationally symmetric about a central indexable axis AI. More precisely, the four-way indexable parting blade 14 is rotationally symmetric by 90°.

[0138] Therefore, for ease of explanation, the features of the coolant passages and insert pockets, as well as all other features, may be described with respect to a portion of the blade simply for ease of viewing, but it should be understood that each rotationally symmetrical corresponding portion also has the same features.

[0139] However, while the coolant passages in the present example are identical, it should be understood that exact identity is not critical for the coolant passages, as slight deviations in the paths are possible (particularly with the flexibility of additive manufacturing, also known as 3D printing). Also, as shown in Figure 6, described below, the coolant passages follow circuitous paths from their respective inlets to their respective insert pockets to which coolant is supplied.

[0140] The first insert pocket 18A includes a base jaw 46, a second jaw 48, and a slot end 50.

[0141] Base jaw 46 defines a base plane PB and has a forward-most point 52 distal to slot end 50 .

[0142] A trailing blade direction DBR is defined along the base plane PB from the forward-most point 52 toward the blade 14. In this non-limiting example, the trailing blade direction DBR is more particularly directed toward the portion of the blade behind the associated second jaw 48. Relative to the trailing blade direction DBR, a leading blade direction DBF, a top blade direction DBU, and a bottom blade direction DBD are defined (all arbitrarily defined relative to the first insert pocket 18A in this example).

[0143] In the rear blade direction DBR from the forward most point 52, the rearmost point 54 is defined at the slot end 50 in this example, although this may not be the case for different insert pocket types.

[0144] Referring now to FIG. 6, an exemplary internal coolant configuration will be described.

[0145] A first coolant passage 56, a second coolant passage 58, a third coolant passage 60, and a fourth coolant passage 62 are shown.

[0146] For ease of viewing, only some features are described relative to the other coolant passages, but it should be understood that each applies to all coolant passages.

[0147] The first coolant passage 56 includes a first inlet 56A, at least one first outlet 56B that opens into the first insert pocket 18A, and a first passage portion 56C that extends from the first inlet 56A to the at least one first outlet 56B (in this case, designated 56B1). For clarity, the first passage portion 56C is the complete extension of the first coolant passage 56 that extends between the first inlet 56A and the at least one first outlet 56B, 56B1.

[0148] More specifically, in the illustrated example, the at least one first outlet 56B comprises a first rake face outlet 56B1 that opens onto the rake face side 16D of the first insert pocket 18A, and a first flank outlet 56B2 that opens onto the flank side 16E of the first insert pocket 18A.

[0149] Similarly, the second coolant passage 58 includes a second inlet 58A, at least one second outlet 58B (in this example, a second rake face outlet 58B1 and a second flank face outlet 58B2) that opens into the second insert pocket 18B, and a second passage portion 58C, and the third coolant passage 60 includes a third inlet 60A and at least one third outlet 58B that opens into the third insert pocket 18C. The fourth coolant passage 62 has a fourth inlet 62A and at least one fourth outlet 62B (in this example, a fourth rake face outlet 62B1 and a fourth flank outlet 62B2) that opens into the fourth insert pocket 18D, and a fourth passage portion 62C.

[0150] 3A, it will be appreciated that, on both the exterior and interior sides, the first inlet 56A, second inlet 58A, third inlet 60A, and fourth inlet 62A each include a pair of converging straight upper inlet edges 56D1, 56D2, 58D1, 58D2, 60D1, 60D2, 62D1, 62D2, all oriented in the same direction. That is, the first inlet 56A includes a first pair of converging straight upper inlet edges 56D1, 56D2, the second inlet 58A includes a second pair of converging straight upper inlet edges 58D1, 58D2, the third inlet 60A includes a third pair of converging straight upper inlet edges 60D1, 60D2, and the fourth inlet 62A includes a fourth pair of converging straight upper inlet edges 62D1, 62D2. More specifically, in this example, each pair converges in a combination of an upper blade direction DBU and a leading blade direction DBF. More specifically, the first inlet 56A, second inlet 58A, third inlet 60A, and fourth inlet 62A each have an apex (i.e., a first apex 56E, a second apex 58E, a third apex 60E, and a fourth apex 62E at the junction of each pair of straight upper inlet edges 56D1, 56D2, 58D1, 58D2, 60D1, 60D2, 62D1, 62D2).

[0151] In this example, the first inlet 56A, second inlet 58A, third inlet 60A, and fourth inlet 62A are four-sided straight-edged polygons and further include a pair of converging straight lower inlet edges 56F1, 56F2, 58F1, 58F2, 60F1, 60F2, 62F1, 62F2, respectively. That is, the first inlet 56A includes a first pair of converging straight lower inlet edges 56F1, 56F2, the second inlet 58A includes a second pair of converging straight lower inlet edges 56F1, 56F2, the third inlet 60A includes a third pair of converging straight lower inlet edges 56F1, 56F2, and the fourth inlet 62A includes a fourth pair of converging straight lower inlet edges 56F1, 56F2.

[0152] The blade 16 is preferably printed (i.e., printed during additive manufacturing) at a 45° orientation relative to the orientation shown in FIG. 3A, and it will be appreciated that advantageously, any of the first insert pocket 18A, second insert pocket 18B, third insert pocket 18C, and fourth insert pocket 18D may be the top insert pocket during printing.

[0153] As an example, the first coolant passage's first inlet 56A is located farther from the farthest point 52 of the first insert pocket 18A than the central cutting edge changing axis AI (the length from the farthest point 52 to the central cutting edge changing axis AI is designated LD1). This allows for a greater cutting depth of the blade 14 than if the first blade inlet 56A were located on the central cutting edge changing axis AI; when the first blade inlet 56A is located on the central cutting edge changing axis AI, the maximum cut-off depth (limited by the blade holder 12) is length LD1 (or even less, since the blade inlet has a region). In the illustrated example, the cut-off depth is closer to length LD2 (albeit somewhat smaller due to the structure of the holder 12) (the length from the farthest point 52 to the first inlet 56A is designated LD2). Nevertheless, the cut-off depth capability of the blade 14 is greater than length LD1.

[0154] Similarly, note that the first inlet 56A is located farther from the farthest point 52 of the first insert pocket 18A than the second inlet 58A, i.e., the second inlet 58A is closer to the farthest point 52 than the first inlet 56A. This allows for the same greater depth advantage described above (i.e., the length LD3 from the farthest point 52 to the second inlet 58A is significantly less than the possible parting depth of the blade 14), but such a configuration provides the additional advantage of the nested coolant passage configuration shown (i.e., the passages surround each other to reach the desired insert pocket without being obstructed by another coolant passage). Indeed, as shown in FIG. 3A, the first inlet 56A is located farther from the farthest point 52 of the first insert pocket 18A than all other inlets 58A, 60A, and 62A.

[0155] 6, the first coolant passage 56 extends in a clockwise direction and surrounds the outer periphery of at least a portion of the second coolant passage 58. Similarly, the second coolant passage 58 extends in a clockwise direction and surrounds the outer periphery of the third coolant passage 60, and so on. Thus, as shown in FIG. 6B, in a cross-section of the blade taken between the first side 42A and the second side 42B, an imaginary radial line LR extending from the central axis AI to any portion of the blade outer circumferential edge 44 intersects at least two of the coolant passages. As noted above, the surrounding or nesting may alternatively be counterclockwise.

[0156] Referring also to FIG. 6B, using the fourth coolant passage 62 as an example, it should be noted that the fourth passage portion 62C can have a single initial passage section 62G, which is divided into multiple subsequent passage sections 62H (which in this example have a first subsequent passage section 62H1 connected to the fourth rake face outlet 62B1 and a second subsequent passage section 62H2 connected to the fourth clearance face outlet 62B2).

[0157] The initial passage portion 62G has a length LCP (measured from the edge of the fourth inlet 62A to the start of the first turn T1 of the fourth passage portion 62C). In particular, the length LCP of the initial passage portion is advantageously significantly longer because the alternative of fitting two parallel passages (not shown) within the same congested area (i.e., completely separate passages from the fourth inlet 62A to the respective fourth rake face outlets 62B1 and fourth flank outlets 62B2) would be more problematic given the relatively limited available space.

[0158] However, the fourth passage portion 62C is divided into the two subsequent passage portions 62H1, 62H2 to supply coolant to the two sides of the fourth insert pocket.

[0159] The shorter of the two subsequent passage sections 62H, which in this example is the first subsequent passage section 62H1, defines a length LOC, which is generally shown as the sum of the segment length LOC1 of the first subsequent passage section and the segment length LOC2 of the first subsequent passage section.

[0160] It is further noted that advantageously, both the first subsequent passage portion 62H1 and the second subsequent passage portion 62H2 have a first terminal linear portion 62I1 and a second terminal linear portion 62I2, respectively, the first terminal linear portion 62I1 adjacent to and opening to the fourth rake face outlet 62B1, and the second terminal linear portion 62I2 adjacent to and opening to the fourth relief face outlet 62B2.

[0161] 6, regarding the passage path of the fourth coolant passage 62 (generally designated "62J"), first note that the initial passage portion 62G extends from a first location 62K1 proximate the fourth inlet 62A in a first direction D1 toward the fourth insert pocket 18D rather than away from the fourth insert pocket 18D (considering the primary path of the initial passage portion 62G, and not the minor portion 62K3 (FIG. 6B) exiting the fourth inlet 62A, which extends in a slightly different direction). For clarity, the first direction D1 extends in a combination of the trailing blade direction DBR and the top blade direction DBU.

[0162] With respect to the first subsequent passage section 62H1 of the fourth coolant passage, where the initial passage section 62G splits into the two subsequent passage sections 62H1, 62H2, there is a first significant turn T1 of the fourth coolant passage 62. In the context of the present invention, a "significant turn" between two adjacent sections of a coolant path is one that makes a turn of at least 25° (i.e., ≧25°).

[0163] At the significant first turn T1, the first subsequent passage section 62H1 of the fourth coolant passage has a non-sharp turn (i.e., the turn is greater than 90°, or even greater than 110°, forming a first passage section first angle μ1 of 123° in this example, as measured by an adjacent straight line drawn as a dashed line through the straight section of the fourth passage section 62C, and the next angle is measured similarly) and a second, smaller turn leading to the first terminal linear section 62I1 (in this example, the first passage section second angle μ2 = 155°).

[0164] More particularly, in the significant first turn portion T1 of the fourth coolant passage 62, with respect to the second subsequent passage portion 62H2 of the fourth coolant passage, which is a passage portion located farther from the fourth outer peripheral minor edge 44D of the blade than the first subsequent passage portion 62H1, the significant first turn portion T1 is steeper (i.e., this turn portion forms a second passage portion first angle α1 that is significantly less than 110°, or even less than 100°, in this example, 96°).

[0165] It will be appreciated that the passageway first angle α1 is less than the first passageway first angle μ1, resulting in a relatively greater pressure drop in the second subsequent passageway section 62H2 than in the first subsequent passageway section 62H1.

[0166] In particular, the second subsequent passage portion 62H2 has a first secondary passage portion 62L that extends adjacent to and parallel to the initial passage portion 58G of the first coolant passage.

[0167] The first sub-passage portion 62L of the fourth coolant passage and the initial passage portion 58G of the first coolant passage are adjacent to each other and extend parallel for a significant length (the significant length is referred to herein as the "extension portion LE" (shown in Figure 6) and is measured along where the two portions are parallel).

[0168] Thereafter, at a second position 62K2, which also includes a significant second turn T2 of the fourth coolant passage (considering the continuous coolant path along the second subsequent passage section 62H2), the passage path extends in a second direction D2 away from the fourth insert pocket 18D than toward the fourth insert pocket 18D. Specifically, the second direction D2 extends in a combination of the leading blade direction DBF and the top blade direction DBU. At this position, there is a significant second turn T2 where the passage section second angle α2 is 139°.

[0169] Thereafter, at a third position 62K3, which also includes a third sharp turn T3 of the fourth coolant passage 62, the passage path extends in a third direction D3 toward the fourth insert pocket 18D rather than away from the fourth insert pocket 18D. The acute angle α of the sharp turn is formed between the straight portion directly following the second position 62K2 and the straight portion following the third position 62K3, creating an extremely sharp turn T3 with an acute angle α of 42°.

[0170] Rather than using the dashed line, an alternative definition for the angle of the sharp turn, which simply refers to the corresponding portion of the second coolant passage, may be defined in terms of radius R (FIG. 6; for ease of viewing, radius R is shown adjacent second clearance outlet 58B2).

[0171] For ease of viewing, the description of the same structure will now continue with respect to the second subsequent passage 60H2 of the third coolant passage 60, shown in the lower left corner of Figure 6B. To compensate for the extremely sharp turn T3, an enlarged cross section of the second subsequent passage 60H2 is shown in the region between the second location 60K2 and the third location 60K3, designated 60M1 (in this example, the region shown is the curved turn 60M1 between the second location 60K2 and the third location 60K3).

[0172] More precisely, the curved turn portion 60M1 is preceded by a leading passage portion 60M2 and followed by a trailing passage portion 60M3, and the two portions, the leading passage portion 60M2 and the trailing passage portion 60M3, are straight.

[0173] Returning to the fourth coolant passage 62 shown in FIG. 6, which separately defines the third turn T3, the so-called "sharp turn" can be considered to be two adjacent significant minor turns, namely, a first minor turn T3A and a second minor turn T3B.

[0174] The first minor turn portion T3A has a passageway third angle α3 of 125°.

[0175] The second minor turn portion T3B has a passageway fourth angle α4 of 100°.

[0176] For ease of viewing, the discussion will continue with reference to the region of the second insert pocket 18B in FIG. 6. (Briefly referring to the second insert pocket 18B and the second coolant passage 58 adjacent to the second insert pocket 18B.) To provide objectivity to the proximity of the third sharp turn T3 to the insert pocket, note that the sharp turn begins at the second location 58K2 (or second turn T2). The distances of the insert pocket length LP and the second position length LS measured from the forward-most point 52 to the second position 62K2 are relatively the same (relatively the same means that the second position length LS is less than twice the size of the insert pocket length LP).

[0177] Similarly, an alternative definition for this proximity could be the closest length LC between the foremost point 52 and the closest point 58N of the closest coolant passage (which in the illustrated example is the second subsequent passage section 58H2 of the second coolant passage).

[0178] A first intermediate distance LI1 between the two coolant passages closest to the second insert pocket 18B (along the illustrated line extending to the nearest point 58N) is shown and is 0.8 mm.

[0179] A second intermediate distance LI2 between the second closest coolant passage (in the illustrated example, the single initial passage portion 60G of the third coolant outlet) and the third closest coolant passage (in the illustrated example, the single initial passage portion 62G of the fourth coolant outlet) is shown and is 1 mm.

[0180] In other words, the distance between adjacent coolant passages is approximately equal to or less than the cross-sectional dimension of the coolant passage itself, i.e., the coolant passages are closely spaced relative to one another.

[0181] As can best be seen in FIG. 1C, the parting blade 14 can be divided into equal sections, specifically, in this example, a first section S1, a second section S2, a third section S3, and a fourth section S4, which in this example can be considered "quadrant".

[0182] 6 and the first coolant passage 56, note that the first inlet 56A of the first coolant passage 56 is located in the third section S3, and the entire sharp turn of the first coolant passage 56 is within the first section SI.

[0183] In particular, the third inlet 60A is also in the first section SI, while the third outlet 60B is in the third section S3.

[0184] A force angle range θ having an apex at a forward-most point 52 is illustrated for the first insert pocket 18A.

[0185] During machining of the workpiece, the force exerted by the workpiece is first transferred to the cutting insert (FIG. 1C) and then to the insert pocket. Because the exact direction of the force varies depending on various variables, the force angle ranges specified are approximations used to illustrate the forces on the blade 14.

[0186] In FIG. 6 , an imaginary diagonal line L1 is drawn within a force angle range θ from the foremost point 52 to show that the imaginary diagonal line L1 intersects three coolant passages (i.e., the second subsequent passage portion 56H2 of the first coolant passage, the initial passage portion 58G of the second coolant passage, and the initial passage portion 60G of the third coolant passage). As further shown along these intersecting coolant passages, a first imaginary extension line E1 extends through the second subsequent passage portion 56H2 of the first coolant passage, and a second imaginary extension line E2 extends through the initial passage portion 58G of the second coolant passage. The first extension line E1 and the second extension line E2 are drawn to extend parallel to their respective coolant paths at the intersection of the diagonal line L1, and are shown to form an extension line angle γ between themselves.

[0187] Returning to the region 58L shown for the example for the second insert pocket 18B, the region 58L is defined between the first imaginary downward line L2 and the rearmost point 54. If the region 58L is considered strictly within the downward direction between the first imaginary downward line L2 and the rearmost point 54 (relative to the insert pocket of the path), then in this example, two coolant passages are provided within the defined region (i.e., the second trailing passage portion 58H2 of the second coolant passage and the first trailing passage portion 60H1 of the third coolant passage). (Note that the downward direction of the second insert pocket 18B shown in the present drawings is the indicated rear blade direction DBR.)

[0188] Referring to FIG. 7, the first cross-sectional shape portion 64 of the second coolant passage 58 along with the initial passage portion 58G is shown.

[0189] Additionally, the second cross-sectional shape portion 66 of the first coolant passage 56 along the second subsequent passage portion 56H2 is shown.

[0190] Regarding the first cross-sectional shape portion 64, the first cross-sectional shape portion 64 has opposing first and second side edges 64A, 64B, a first straight upper edge 64C extending from the first side edge 64A at a first obtuse angle β1 within the passage portion, a second straight upper edge 64D extending from the second side edge 64B at a second obtuse angle β2 within the passage portion, and a third obtuse angle β3 within the passage portion. 4A and a second straight lower edge 64F extending from the opposite side of the second side edge 64B at a fourth obtuse angle β4 within the passage portion, the first upper edge 64C and the second upper edge 64D joining at a concave upper corner edge 64G, and the first lower edge 64E and the second lower edge 64F joining at a concave lower corner edge 64H.

[0191] In particular, the first and second side edges 64A, 64B are longer than the first and second top edges 64C, 64D, respectively, for the first cross-sectional shape, while the first and second side edges 66A, 66B of the second cross-sectional shape 66 are substantially the same length as the first and second top edges 66C, 66D of the second cross-sectional shape. While a more elongated shape would be preferable for coolant flow, this shape is not provided due to space constraints. It will be appreciated that the cross sections of the first and second cross-sectional shapes 64, 66 may be interchangeable. However, because the coolant must be divided among the subsequent passage sections, it is preferred that the initial passage section of the coolant passage have a larger cross-sectional area than the subsequent passage sections.

[0192] Both the first cross-sectional shape portion 64 and the second cross-sectional shape portion 66 are elongated in the upward direction DBU and the downward direction DBD of the blade.

[0193] The first cross-sectional shape portion 64 is mirror-symmetric about a first mid-plane PM1 that is perpendicular to and extends through the midpoint between the first 42A and second 42B side edges of the blade.

[0194] The first cross-sectional shape portion 64 (and also the second cross-sectional shape portion 66) is mirror-symmetric about a second mid-plane PM2, which is parallel to and extends midway between the first and second side edges 42A, 42B of the blade.

[0195] 4, note that first rake face outlet 56B1 has reduced its previously elongated cross-sectional area to a basic square shape (the square shape is rotated 45 degrees relative to the upward direction DBU and downward direction DBD, and is therefore also referred to as a "diamond shape"). While there is room to make the first rake face outlet more elongated, which would desirably increase the cross-sectional area, a less elongated outlet allows for greater structural strength to the region above the first rake face outlet (note that greater structural strength is essentially provided to material 68 above first rake face outlet 56B1).

[0196] Alternatively, to provide similar strength to the first flank outlet 56B2 shown in FIG. 5 , the shape of the first flank outlet 56B2 is still elongated to provide a significant cross-sectional area, and therefore coolant flow. However, an elongated diamond shape is provided. In other words, the first flank outlet 56B2 now has shorter first and second side edges 70A and 70B (essentially concavely curved side edges) than the previous first cross-sectional shape 64 near the beginning of the first coolant passage 58 shown in FIG. 7 . This shortening also provides greater structural strength in the area above the first flank outlet 56B2, but also provides additional coolant flow. Explaining the diamond shape of the first flank outlet, first flank outlet 56B2 comprises first and second side edges 70A, 70B that are shorter than first and second upper edges 70C, 70D, and first and second side edges 70A, 70B that are shorter than first and second lower edges 70E, 70F. In such a case, first obtuse angle β5, second obtuse angle β6, third obtuse angle β7, and fourth obtuse angle β8 are all 120°.

Claims

1. an opposing blade first side and a blade second side; a blade outer peripheral edge connecting the first blade side and the second blade side; a central cutting edge replacement axis extending through the center of the blade first side and the blade second side; a first insert pocket, a second insert pocket, and a third insert pocket located along the outer periphery of the blade; a first coolant passage, a second coolant passage, and a third coolant passage; the first coolant passage includes a first inlet, at least one first outlet opening into the first insert pocket, and a first passage portion extending between the first inlet and the at least one first outlet; the second coolant passage includes a second inlet, at least one second outlet opening into the second insert pocket, and a second passage portion extending between the second inlet and the at least one second outlet; the third coolant passage comprises a third inlet, at least one third outlet opening into the third insert pocket, and a third passage portion extending between the third inlet and the at least one third outlet; the at least one first outlet comprises a first rake face outlet opening to a rake face side of the first insert pocket and a first flank outlet opening to a flank side of the first insert pocket; the first entrance is located farther from the farthest point of the first insert pocket than at least one of (a) the second entrance and (b) the central cutting edge replacement axis; Replaceable cutting edge blade.

2. The indexable parting blade of claim 1 , wherein the second coolant passage prevents a direct path from the first inlet to at least one of the at least one first outlet.

3. 3. The indexable parting blade according to claim 1, wherein the first inlet is located farther from the farthest point of the first insert pocket than both the second inlet and the central indexable axis.

4. The indexable parting blade according to any one of claims 1 to 3, wherein the first inlet is located farther from the farthest point of the first insert pocket than all other inlets of the parting blade.

5. The passage path of the first passage portion is a first location proximate the first inlet, where the passage path extends in a first direction toward the first insert pocket rather than away from the first insert pocket; a second location further along the passage path from the first inlet than the first location, the passage path extending in a second direction further away from the first insert pocket than toward the first insert pocket; a third location further along the passage path from the first inlet than the second location, wherein the passage path extends in a third direction toward the first insert pocket rather than away from the first insert pocket; The indexable parting blade according to any one of claims 1 to 4, comprising:

6. at least the first coolant passageway passes through a sharp turn adjacent the first flank exit opening; The indexable parting blade according to any one of claims 1 to 5, wherein the sharp turn portion defines a turn portion acute angle α0.

7. The sharp turn portion is U-shaped, The indexable parting blade according to claim 6, wherein the acute angle α0 satisfies the condition: 80°<α0<20°.

8. The indexable parting blade according to claim 7, wherein the sharp turn portion satisfies the condition: 70°<α0<30°.

9. The indexable parting blade according to any one of claims 6 to 8, wherein the sharp turn portion has a radius of curvature R that satisfies the condition R<5 mm.

10. The indexable parting blade according to claim 9, wherein the sharp turn portion has a radius of curvature R that satisfies the condition R<3.5 mm.

11. 11. An indexable parting blade according to any one of claims 1 to 10, wherein all of the passages of the parting blade are nested and all extend in a clockwise direction from their respective inlets, or alternatively, all extend in a counterclockwise direction from their respective inlets.

12. The passage path of the passage portion is A passage portion that satisfies the condition: 25°<α1<155°. A first significant turn portion that forms a first angle α1. a second significant turn portion forming a passage portion second angle α2 that satisfies the condition: 25°<α2<155°; a passage portion that satisfies the condition: 25°<α3<155°; a third significant turn portion that forms a third angle α3; a fourth significant turn portion forming a fourth angle α4 of the passage portion satisfying the condition: 25°<α4<155°; Along the passage path, the second sharp turn is downstream from the first sharp turn; the third sharp turn is downstream from the second sharp turn; The indexable parting blade according to any one of claims 1 to 11, wherein the fourth significant turn portion is downstream from the third significant turn portion.

13. The indexable parting blade according to claim 12, wherein the first angle α1 of the passage portion satisfies the condition: 70°<α1<130°.

14. The indexable parting blade according to claim 12 or 13, wherein the second angle α2 of the passage portion satisfies the condition: 110°<α2<155°.

15. The indexable parting blade according to any one of claims 12 to 14, wherein the angle α3 of the third passage portion satisfies the condition: 90°<α3<155°.

16. The indexable parting blade according to any one of claims 12 to 15, wherein the angle α4 of the fourth passage portion satisfies the condition: 70°<α4<130°.

17. the first insert pocket comprises a primary jaw, a second jaw opposite the primary jaw, and a slot end connecting the primary jaw and the second jaw; the primary jaw defines a primary plane and has a forward-most point distal to the slot end; the basic plane defines a rearward direction defined from the forward-most point toward the blade, a forward direction opposite the rearward direction, an upward direction perpendicular to the forward direction and the rearward direction and away from the basic jaw and the blade, and a downward direction opposite the upward direction; a force angle range θ has a vertex at the foremost point, is defined between the downward direction and the rearward direction, and satisfies the condition: 50°>θ>10°; The indexable parting blade according to any one of claims 1 to 16, wherein an imaginary oblique line L1 extending from the foremost point within the force angle range θ intersects at least two coolant passages.

18. the first insert pocket comprises a primary jaw, a second jaw opposite the primary jaw, and a slot end connecting the primary jaw and the second jaw; the primary jaw defines a primary plane and has a forward-most point distal to the slot end; the basic plane defines a rearward direction defined from the forward-most point toward the blade, a forward direction opposite the rearward direction, an upward direction perpendicular to the forward direction and the rearward direction and away from the basic jaw and the blade, and a downward direction opposite the upward direction; The indexable parting blade according to any one of claims 1 to 17, wherein the first insert pocket has a rearmost point, and defines a region having at least two different coolant passages in the strictly downward direction between a first imaginary underline (L2) extending from the rearmost point and a position forward from the first imaginary underline (L2).

19. At least a portion of the first passage portion has a cross-sectional shape; the cross-sectional shape comprises opposing first and second side edges extending along the blade first and second sides; a first straight upper edge extending from the first side edge within the passage portion at a first obtuse angle β1; a second straight upper edge extending from the second side edge within the passage portion at a second obtuse angle β2; a first straight lower edge extending from the opposite side of the first side edge to the first upper edge within the passage portion at a third obtuse angle β3; and a second straight lower edge extending from the opposite side of the second side edge to the second upper edge within the passage portion at a fourth obtuse angle β4; the first upper edge and the second upper edge are joined at an upper corner edge; The indexable parting blade according to any one of claims 1 to 18, wherein the first lower edge portion and the second lower edge portion are connected at a lower corner edge portion.

20. the first inlet, the second inlet, and the third inlet open to one or both of the first side of the blade and the second side of the blade; each said inlet having a pair of converging straight upper inlet edges; 20. An indexable parting blade according to any one of claims 1 to 19, wherein all of the upper inlet edges are oriented in the same direction.

21. the first passage portion includes a curved turn; The preceding passage section precedes the curved turn section, and the following passage section follows the curved turn section, 21. An indexable parting blade according to claim 1, wherein a turn cross-sectional area measured perpendicular to the coolant passage through the curved turn is greater than a preceding passage cross-sectional area measured perpendicular to the coolant passage through the preceding passage.

22. 22. The indexable parting blade of claim 21, wherein the turn cross-sectional area is greater than a trailing passage cross-sectional area measured perpendicular to the coolant passage through the trailing passage.

23. a fourth insert pocket located along the outer periphery of the blade; a fourth coolant passage; 23. The indexable parting blade according to any one of claims 1 to 22, wherein the fourth coolant passage comprises: a fourth inlet; at least one fourth outlet opening into the fourth insert pocket; and a fourth passage portion extending between the fourth inlet and the at least one fourth outlet.

24. In a cross section of the parting blade taken between the first side and the second side, an imaginary radial line (LR) extending from the central axis (AI) to any part of the outer peripheral edge of the blade is further provided, An indexable parting blade according to any one of claims 1 to 23, wherein the imaginary radial line (LR) intersects at least two of the coolant passages.

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