Indexable parting tool with a tortuous coolant passage

Abstract

An indexable parting tool having opposite first and second sides of the tool, a peripheral edge of the tool, a central indexing axis, and at least a first, a second, and a third blade pocket positioned along the peripheral edge of the tool. The parting tool also has a first coolant passage, a second coolant passage, and a third coolant passage, each forming a coolant path from a corresponding inlet to a corresponding one of the blade pockets. Each coolant passage includes a rake outlet opening into a rake side portion of its corresponding blade pocket and a relief outlet opening into a relief side portion of the same blade pocket. The inlet corresponding to a given coolant passage is positioned farther from the blade pocket of the coolant passage than at least one of (a) the inlet corresponding to a different coolant passage and (b) the central indexing axis.

Description

TECHNICAL FIELD

[0001] The subject matter of the present invention relates to an indexable parting tool (hereinafter also referred to as "tool") and a tool holder (hereinafter also referred to as "holder"), and a tool assembly comprising both the tool and the holder, all constructed for parting. More particularly, the present invention relates to an indexable parting tool having a plurality of coolant channels, each of which is configured to supply coolant to a corresponding blade pocket. BACKGROUND OF THE INVENTION

[0002] As the name implies, parting tools can be considered to have a "tool" shape, which means they have a thin blade or plate shape for entering a metal workpiece to a relatively large depth for parting operations. In other words, the tool thickness measured perpendicular to the first and second sides has hitherto been the smallest dimension of the tool.

[0003] The most traditional and common parting tools are elongated.

[0004] It will be understood that members constructed for parting can be used for grooving operations at relatively small depths, however, in some cases, the reverse may not be true.

[0005] Due to the difficulty of supplying coolant to the cutting blade located within the slot (of the workpiece being parted), it has become common to provide parting tools with internal coolant passages.

[0006] The present invention is an improvement of a previous invention described by the applicant in US 2019 / 0240741. However, the present invention is not limited to the four-way indexable parting tool shown in FIGS. 18B to 20B, and indeed also applies to, for example, the three-way indexable tool of at least FIGS. 21A to 23D. The four-way indexable parting tool is mentioned because the coolant channel difficulties addressed in the present application are referred to with reference to the embodiments of FIGS. 18B to 20B.

[0007] Referring to this embodiment, a rotationally symmetric parting tool and a holder therefor are described. The tool includes a single coolant channel for each blade pocket. Each coolant channel includes a tool inlet orifice and a tool outlet orifice.

[0008] The tool inlet orifice is preferably not located on the central index axis (or in other words, spaced from the central index axis) to allow for a greater cutting depth for the indexable parting tool. It will be understood that while the parting tool may visually resemble a rotating slitting disc, the latter uses all of its cutting blades in a single operation and does not index in a holder to bring a new blade pocket to the enabled position for machining.

[0009] Notably, the tool outlet orifice is the only outlet orifice, which provides for the blade seat and is directed above the rake surface of the cutting blade held by the blade seat.

[0010] While it is known that in an elongate parting tool, two tool outlet orifices are provided for each blade seat, due to the four-way rotatable symmetry of the parting tool, it has only been found practicable to provide a single tool outlet orifice (and in some cases, a single outlet orifice directed above the rake surface is a preferred embodiment, as described in US 2013 / 0236253 assigned to the present applicant). It will be noted that due to the many difficulties overcome in the present invention, more than one outlet orifice is not proposed.

[0011] One such difficulty is that when there are several blade pockets and the tool inlet orifices associated with each pocket are located at non-central locations (or at least at locations not in the same section of the tool as or adjacent to the tool outlet orifice), a direct route for one passage from the tool inlet orifice to the tool outlet orifice is blocked by another passage having a similar path.

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

[0013] For the sake of good order, it will be noted that the present invention relates to coolant channels for a indexable parting tool, and the features regarding other components and all features unrelated to coolant disclosed in US 2019 / 0240741 are incorporated herein by reference.

[0014] It will be noted that various coolant channels are described in other publications.

[0015] USP 10,661,352 discloses a parting tool having three coolant channels for a single blade pocket.

[0016] Notably, USP 10,661,352 is an elongate parting tool (the most common shape of parting tool today), which does not have the same space constraints of at least a three-way or four-way indexable parting tool as mentioned above with reference to US 2019 / 0240741, due to the larger structure and smaller number of blade pockets, and thus each blade pocket can be easily provided with two (or even three) tool outlet orifices associated therewith.

[0017] It will be understood that the problems overcome by the present invention particularly arise in parting tools having a relatively high number of blade pockets for a given tool size. As can be seen, with regard to the number of coolant channels and the slender shape of the parting tool, the parting tool disclosed in USP 10,661,352 does not have significant space constraints (since there is no difficulty with channels intersecting other channels in a direct path, as exists in US 2019 / 0240741).

[0018] A further aspect of the present invention relates to an advantageous cross-sectional shape developed for coolant channels produced by additive manufacturing, which shape is particularly advantageous for indexable parting tools.

[0019] In USP 10,661,352, although circular cross-section channels that can be produced by conventional manufacturing methods are described in connection with most embodiments, it is noted that with an additive manufacturing process, other cross-sections (such as polygonal or elliptical) are possible.

[0020] Similarly, in DE 20 2018 105 949, a design is shown that shows an elliptical cross-section.

[0021] It is also known in the field of additive manufacturing to produce coolant channels having a teardrop shape (i.e., including a circular bottom edge and an upper inverted v-shaped top edge, the purpose of the top edge being to reduce top-side drooping during manufacturing).

[0022] It is an object of the present invention to provide a new and improved indexable parting tool. SUMMARY OF THE INVENTION

[0023] According to a first aspect of the present invention, there is provided an indexable parting tool comprising:

[0024] opposite first and second tool sides;

[0025] a tool outer peripheral edge connecting the first and second tool sides;

[0026] a central index axis extending through the centers of the first and second tool sides;

[0027] a first blade pocket, a second blade pocket, and a third blade pocket positioned along the tool outer peripheral edge; and

[0028] a first coolant channel, a second coolant channel, and a third coolant channel;

[0029] The first coolant channel includes a first inlet, at least one first outlet opening into the first blade pocket, and a first channel portion extending between the first inlet and the at least one first outlet;

[0030] The second coolant passage includes a second inlet, at least one second outlet opening into the second blade pocket, and a second passage portion extending between the second inlet and the at least one second outlet; and

[0031] The third coolant passage includes a third inlet, at least one third outlet opening into the third blade pocket, and a third passage portion extending between the third inlet and the at least one third outlet;

[0032] Wherein:

[0033] At least one first outlet includes a first rake outlet opening into the rake side portion of the first blade pocket and a first relief outlet opening into the relief side portion of the first blade pocket; and

[0034] The first inlet is positioned farther from the farthest point of the first blade pocket than at least one of (a) the second inlet and (b) the central index axis.

[0035] The present invention for the first time allows two outlets at a single blade pocket, regardless of the spatial constriction with at least three-way indexability. This also allows for a preferably large separation depth to be possible, since the first inlet is relatively far from at least one of the first outlets.

[0036] For the sake of good order, it will be noted that the other aspects described below are advantageous and not even restricted to at least three-way indexability (or in other words, at least three blade pockets, which are preferably but optionally equally spaced about the central index axis). Nevertheless, it will be understood that the aspects described below may also advantageously have three-way indexability (i.e., three blade pockets) or more.

[0037] One way is that the first inlet can be positioned at a distance farther from the farthest point of the first blade pocket than the second inlet. Thus, even if the second inlet and the associated second coolant passage block the direct path to at least one of the two outlets of the first coolant passage, a preferably relatively large separation depth can be achieved. In other words, the second coolant passage can block the direct path from the first inlet to at least one of the at least one first outlet.

[0038] Alternatively or in addition, the first inlet can be positioned at a distance farther from the farthest point of the first blade pocket than the central index axis, which extends through the centers of the first side and the second side of the tool, thereby similarly allowing a relatively large separation depth to be achieved.

[0039] It will be understood that it is extremely difficult or impracticable to have multiple turns for the coolant path using conventional machining methods (which would subsequently require blocking at the drilled entry holes, etc.). The present invention utilizes a nested coolant passage configuration.

[0040] Although there is a risk of unduly weakening the tool structure with multiple coolant channels extending parallel or substantially parallel, especially below the base jaws of the blade pocket where the main machining forces are applied, the illustrated design was found to be sufficiently robust for the parting operation.

[0041] According to a second aspect of the invention, there is provided an indexable parting tool comprising: a first tool side and a second tool side opposite; a tool outer periphery connecting the first tool side and the second tool side; a first blade pocket and a second blade pocket positioned along the tool outer periphery; and a first coolant channel and a second coolant channel; the first coolant channel comprising: a first inlet; at least one first outlet opening into the first blade pocket; a first channel portion extending from the first inlet to the at least one first outlet opening; the second coolant channel comprising: a second inlet; at least one second outlet opening into the second blade pocket; a second channel portion extending from the second inlet to the at least one second outlet opening; wherein the passage path of the first channel portion comprises: a first position proximal to the first inlet, wherein the passage path extends in a first direction that is more towards the first blade pocket than away from the first blade pocket; a second position further from the first inlet along the passage path than the first position, wherein the passage path extends in a second direction more away from the first blade pocket than towards the first blade pocket; and a third position further from the first inlet along the passage path than the second position, wherein the passage path extends in a third direction more towards the first blade pocket than away from the first blade pocket.

[0042] It will be understood from the drawings that in the available shrinkage areas, sharp turns are required for the coolant channels to bypass other blocked coolant channels and direct to the relevant cutting zones (i.e., at the workpiece or the cutting blade).

[0043] It will be understood that previously known coolant channels typically have turns of at most only slightly greater than 90°. This is because sharper turns cause a more severe pressure drop, which is disadvantageous and thus known to be avoided.

[0044] It will be understood that the sharp turn defined in the second or third aspect may alternatively be defined as a U - turn. Drawing imaginary lines along the two arms of the U - shape at the final turning portion leading to the third position, the sharp turn forms an acute angle satisfying the conditions: α0 < 80°, preferably α0 < 70°, more preferably α0 < 60°, and even more preferably α0 < 50° because the latter value leaves the most compact form (desirable for the shrinking space but not desirable for the coolant flow). Nevertheless, in order to reduce the pressure drop, it is still preferred that α0 > 20°, more preferably α0 > 30°.

[0045] Nonetheless, it is believed that such pressure drops will still provide more coolant to the cutting blade or workpiece than without the entire coolant outlet. Additionally, to counteract the pressure drop, an enlarged cross-section at the sharp turn is developed, as described below.

[0046] As mentioned above, it is also more difficult to produce a sharp turn (this turn can truly be considered two closely spaced significant turns) with traditional manufacturing methods (e.g., because multiple blocking operations such as welding would also be required).

[0047] While the example shown in the figures shows a sharp turn below the blade pocket (i.e., related to the sub-channel that supplies coolant to the clearance side of the pocket), the channels can be nested in reverse (not shown) for the sharp turn to alternately occur at the rake side of the pocket. In other words, the channels can extend from the inlet in a counterclockwise direction instead of the clockwise direction illustrated (still bypassing the adjacent (in the rotational sense) coolant inlet by extending between the adjacent coolant inlet and the outer periphery of the tool before reaching the blade pocket). Even though the preferred example shown has a sharp turn at the clearance side of the blade pocket (more attention is paid to this sharp turn regarding the cutting force), it is preferred that there is a more effective coolant supply at the rake side of the blade pocket, and thus this arrangement is preferred. Nonetheless, the reverse-nested arrangement is also a viable possibility.

[0048] Another way is that the present invention can be expressed as the path making a large number of significant turns.

[0049] According to a third aspect of the present invention, there is provided an indexable parting tool, comprising: a first tool side and a second tool side that are opposite; a tool outer periphery that connects the first tool side and the second tool side; a first insert pocket and a second insert pocket that are positioned along the tool outer periphery; and a first coolant passage and a second coolant passage; the first coolant passage comprising: a first inlet; at least one first outlet that opens into the first insert pocket; a first passage portion that extends from the first inlet to the at least one first outlet opening; the second coolant passage comprising: a second inlet; at least one second outlet that opens into the second insert pocket; a second passage portion that extends from the second inlet to the at least one second outlet opening; wherein the passage path of the first passage portion comprises: a first significant turn that forms a first angle α1 of the passage portion satisfying the condition: 25° < α1 < 155°; a second significant turn that forms a second angle α2 of the passage portion satisfying the condition: 25° < α2 < 155°; a third significant turn that forms a third angle α3 of the passage portion satisfying the condition: 25° < α3 < 155°; and a fourth significant turn that forms a fourth angle α4 of the passage portion satisfying the condition: 25° < α4 < 155°, wherein: along the passage path, the second significant turn is downstream of the first significant turn, the third significant turn is downstream of the second significant turn, and the fourth significant turn is downstream of the third significant turn.

[0050] It will be understood from the above that, in this aspect, the final "sharp turn" or "U-turn" may alternatively be defined as two adjacent significant turns (the "significant turn" in this application is defined as forming an angle greater than 25°, preferably greater than 45° and less than 155°).

[0051] Between adjacent turns, there may be a continuous curved connection.

[0052] Different from the large turns shown in the prior art, the sharp turn may have a very small radius of curvature R of less than 5 mm (R < 5 mm), preferably R < 3.5 mm, and more preferably R < 2 mm. It will be understood that these preferences are only beneficial due to the need to handle spatial constraints and are not beneficial from the perspective of pressure drop.

[0053] The first angle α1 of the passage portion preferably satisfies the condition: 70° < α1 < 130°, preferably 80° < α1 < 120°, more preferably 90° < α1 < 110°.

[0054] The second angle α2 of the passage portion preferably satisfies the condition: 110° < α2 < 155°, preferably 125° < α2 < 150°, more preferably 130° < α2 < 150°.

[0055] The third angle α3 of the channel portion preferably satisfies the condition: 90° < α3 < 155°, preferably 105° < α3 < 140°, more preferably 115° < α3 < 135°.

[0056] The fourth channel angle α4 preferably satisfies the condition: 70° < α4 < 130°, preferably 80° < α4 < 120°, more preferably 90° < α4 < 110°.

[0057] As shown in US 2019 / 0240741 Figure 6 the total cutting force FC on the cutting blade and thus the blade pocket holding the cutting blade is directed more in the downward direction than in the backward direction.

[0058] As will be appreciated, one way to achieve the provision of coolant to both sides of the blade pocket of the indexable parting tool for the shrinkage space is that a plurality of closely layered coolant channels must be provided, even below the blade pocket in which the force is directed.

[0059] Accordingly, in a fourth aspect of the present invention, there is provided an indexable parting tool comprising: opposite first and second sides of the tool; a tool outer periphery connecting the first and second sides of the tool; and first and second blade pockets located along the tool outer periphery; the first blade pocket is located along the tool outer periphery and includes a base jaw, a second jaw opposite the base jaw, and a groove end connecting the base jaw and the second jaw; the base jaw defines a base plane and has a foremost point distal to the groove end; the base plane defines: a backward direction which is defined from the foremost point towards the tool; a forward direction which is opposite to the backward direction; an upward direction which is perpendicular to the forward and backward directions and away from the base jaw and the tool; and a downward direction which is opposite to the upward direction; and wherein: the force angle range θ has a vertex at the foremost point and is defined between the downward direction and the backward direction and satisfies the condition: 50° > θ > 10°; and an imaginary diagonal line L1 extending from the foremost point within the force angle range θ intersects at least two coolant channels.

[0060] As will be appreciated, due to the above concern of weakening the already thin parting tool, alternative definitions (not regarding the force angle but the location of the plurality of coolant paths with respect to the blade pocket) are similarly counterintuitive (even more counterintuitive as getting closer to the blade pocket).

[0061] Accordingly, in a fifth aspect of the present invention, there is provided an indexable parting tool, comprising: a first side of the tool and a second side of the tool that are opposite; a tool outer peripheral edge that connects the first side of the tool and the second side of the tool; and a first blade pocket and a second blade pocket that are positioned along the tool outer peripheral edge; the first blade pocket is positioned along the tool outer peripheral edge and includes a base jaw, a second jaw opposite the base jaw, and a groove end that connects the base jaw and the second jaw; the base jaw defines a base plane and has a foremost point distal to the groove end; the base plane defines: a rearward direction that extends from the foremost point towards the tool; a forward direction that is opposite to the rearward direction; an upward direction that is perpendicular to the forward direction and the rearward direction and away from the base jaw and the tool; and a downward direction that is opposite to the upward direction; and wherein: the first blade pocket has a rearmost point; and in the downward direction exactly between a first imaginary downward line L2 extending from the rearmost point and in front of the first imaginary downward line L2, a region is defined that includes at least two different coolant channels.

[0062] During the development of the indexable parting tool of the present invention, a favorable cross-sectional shape of the coolant channel was developed.

[0063] Accordingly, in a sixth aspect of the present invention, there is provided an indexable parting tool, comprising: a first side of the tool and a second side of the tool that are opposite; a tool outer peripheral edge that connects the first side of the tool and the second side of the tool; a first blade pocket and a second blade pocket that are positioned along the tool outer peripheral edge; and a first coolant channel; the first coolant channel includes: a first inlet; at least one first outlet that opens into the first blade pocket; a channel portion that extends from the first inlet to the at least one first outlet opening; wherein: at least a portion of the channel portion includes a cross-sectional shape that includes: opposite first side edges and second side edges that extend along the first side of the tool and the second side of the tool; a first straight upper edge that extends from the first side edge inside the channel portion at a first obtuse angle β1; a second straight upper edge that extends from the second side edge inside the channel portion at a second obtuse angle β2; a first straight lower edge that extends from the opposite side of the first side edge inside the channel portion at a third obtuse angle β3 to the first upper edge; a second straight lower edge that extends from the opposite side of the second side edge inside the channel portion at a fourth obtuse angle β4 to the second upper edge; the first upper edge and the second upper edge are connected at an upper corner edge; and the first lower edge and the second lower edge are connected at a lower corner edge.

[0064] Although teardrop-shaped coolant channels are known, i.e., having converging straight upper edges to reduce the collapse of the upper side of the coolant channel, this shape also allows the same effect, even in the case of multiple coolant channels where there is no distinct upper edge due to large turning paths. Although the channel may vary at its different parts, it is preferred that the cross-sectional shape remains uniform over at least most of the channel to avoid pressure drop to the greatest extent possible.

[0065] In the above-mentioned publications, an oval shape is also used. Although such a shape will perhaps provide a larger cross-sectional area than the shapes defined above and one would think that this would provide a better coolant flow, it has been found that straight upper edges and straight lower edges can be even more beneficial as it has been found that the surface finish of the channel is improved over the upper or lower curved edges, and thus even in the case of a reduced cross-sectional area (compared to the oval shape), straight edges are preferred.

[0066] The preferences for the cross-sectional shape are as follows.

[0067] The first side edge and the second side edge extend parallel to the first side of the tool and the second side of the tool.

[0068] Both the first side edge and the second side edge are longer than each of the first upper edge and the second upper edge.

[0069] Both the first side edge and the second side edge are longer than each of the first lower edge and the second lower edge.

[0070] The cross-sectional shape elongates in a direction parallel to the first side of the tool and the second side of the tool.

[0071] The cross-sectional shape is mirror-symmetric about a first intermediate plane that is perpendicular to and extends through the midpoints of the first side edge and the second side edge.

[0072] The cross-sectional shape is mirror-symmetric about a second intermediate plane that is parallel to and extends through the midpoints of the first side edge and the second side edge.

[0073] The channel portion has a defined cross-sectional shape along most of its length.

[0074] The second coolant channel includes a second inlet, at least one second outlet opening into the second blade pocket, and a second channel portion extending between the second inlet and the at least one second outlet; the second channel portion has a defined cross-sectional shape along most of its length.

[0075] The third coolant passage includes a third inlet, at least one third outlet opening into a third blade 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 most of its length.

[0076] At at least one first outlet, the cross-sectional shape of the first outlet includes a first side edge and a second side edge that are shorter than a previous portion of the passage portion.

[0077] At at least one first outlet, the cross-sectional shape of the first outlet includes a first side edge and a second side edge that are shorter than a first upper edge and a second upper edge.

[0078] At at least one first outlet, the cross-sectional shape of the first outlet includes a first side edge and a second side edge that are shorter than a first lower edge and a second lower edge.

[0079] Notably, the outlet preferably further reduces the coolant flow over the elliptical shape, but is desirable for structural strength purposes.

[0080] The upper corner edges and the lower corner edges are concave in shape.

[0081] Another related development is in the aspect of the oriented inlet shape for indexable parting tools. For ease of production, printing is allowed without regard to a particular indexable orientation, and all inlets are similarly oriented.

[0082] Thus, according to a seventh aspect of the present invention, there is provided an indexable parting tool comprising: opposite first and second sides of the tool; a tool outer peripheral edge connecting the first and second sides of the tool; first, second, and third blade pockets positioned along the tool outer peripheral edge; and first, second, and third coolant passages; the first coolant passage including a first inlet, at least one first outlet opening into the first blade pocket, and a first passage portion extending between the first inlet and the at least one first outlet; the second coolant passage including a second inlet, at least one second outlet opening into the second blade pocket, and a second passage portion extending between the second inlet and the at least one second outlet; and the third coolant passage including a third inlet, at least one third outlet opening into the third blade pocket, and a third passage portion extending between the third inlet and the at least one third outlet; wherein: the first inlet, the second inlet, and the third inlet open into one or both of the first and second sides of the tool; and each inlet includes a pair of converging straight upper inlet edges, all of which are oriented in the same direction.

[0083] Although preferably, the other orifices in the first and second sides of the tool are preferably, but not limited to, circular cross-sectional shape (as shown), there are no such considerations required for the inlets as they do not require screws to extend therethrough.

[0084] Although all inlets may include a standard teardrop shape, a four-way straight-sided polygon (in other words, a 45° rotated square) is preferred for a four-way indexable tool. Similarly, a triangular shape (preferably equilateral) is preferred for a three-way indexable tool.

[0085] Referring again to the sharp turns mentioned in the second and third aspects, develop advantageous ways to compensate for the constriction of the fluid flow.

[0086] That is, according to an eighth aspect of the present invention, there is provided a parting tool comprising: opposite first and second sides of the tool; a tool outer periphery connecting the first and second sides of the tool; at least a first blade pocket; and a first coolant passage; the first coolant passage including a first inlet, at least one first outlet opening into the first blade pocket, and a first passage portion extending between the first inlet and the at least one first outlet; wherein: the first passage portion includes a curved turn that is preceded by a preceding passage portion and followed by a succeeding passage portion; and wherein the cross-sectional area of the turn measured perpendicular to the coolant path through the curved turn is greater than the cross-sectional area of the preceding passage portion measured perpendicular to the coolant path through the preceding passage portion.

[0087] Thus, the enlarged cross-section at the bend compensates for the detriment of the sharp turn.

[0088] Preferably, the cross-sectional area of the turn may also be greater than the cross-sectional area of the succeeding passage portion measured perpendicular to the coolant path through the succeeding passage portion.

[0089] Generally speaking, it will be understood that the present invention relates to a parting tool (which has a single enabled blade pocket during a machining operation) and does not relate to a rotary tool (which uses multiple cutting blades during a given operation).

[0090] According to a ninth aspect of the present invention, there is provided an indexable parting tool comprising: a first tool side and a second tool side that are opposite; a tool outer periphery that connects the first tool side and the second tool side; a central indexing axis (AI) that extends through the centers of the first tool side and the second tool side; at least a first blade pocket, a second blade pocket, and a third blade pocket that are positioned along the tool outer periphery, and at least a first coolant passage, a second coolant passage, and a third coolant passage, each coolant passage forming a passage path from an associated inlet to a corresponding one of the blade pockets, and each coolant passage including a rake exit that opens into a rake side portion of its corresponding blade pocket, a relief exit that opens into its corresponding blade pocket, and a passage portion that connects its associated inlet to the rake exit and the relief exit; wherein: in a cross-section of the parting tool taken between the first side and the second side, any imaginary radial line (LR) extending from the central axis (A1) to the tool outer periphery intersects at least two of the coolant passages.

[0091] Accordingly, according to a tenth aspect of the present invention, there is provided a tool assembly comprising an indexable parting tool according to any one of the foregoing aspects and a tool holder configured to hold the parting tool such that only one of the blade pockets of the parting tool is positioned for enabling use.

[0092] The tool holder can be any of the features known in tool holders of the prior art and is most preferably of the type described in US2019 / 0240741.

[0093] While the main inventive features of the present invention are described in the separate aspects above, it will be understood that any combination of the main inventive features (as illustrated in the drawings) is also possible.

[0094] Summarizing the main features, the parting tool according to the present invention can have one or more of the following: (a) a first inlet positioned relatively far from the farthest point of the blade pocket; (b) a sharp turn; (c) more than one coolant passage in the path of the cutting force or alternatively below the blade pocket; (d) at least one and preferably all of the passage portion cross-sectional shapes including straight converging straight upper and lower edges; (e) all inlets having straight converging straight upper edges oriented in the same direction.

[0095] Preferred features of all of the above aspects will now be described.

[0096] It will be understood that there is more applicability of the present invention for non - slender regular shapes (e.g., triangles, squares, etc.), but it is not restricted thereto. In other words, the parting tool may be rotatable about a central indexing axis that extends through the centers of its first and second sides. However, it will be understood that the present invention is applicable to any parting tool that does not have sufficient space for the desired coolant channels. For example, an obvious case where the present invention can be beneficial for a slender rectangular (standard shape) parting tool is when the parting tool has four blade pockets and thus requires a relatively large number of coolant channels.

[0097] Similarly, since the present invention is more applicable to tools with space constraints, it will be understood that there is more applicability for three - way indexable tools (i.e., having three blade pockets) compared to two - way indexable tools. This is for a similar reason, where a tool with three blade pockets requires more coolant channel space compared to a similar - sized tool with two blade pockets. In the same way, the present invention is more advantageous in four - way indexable tools than in three - way indexable tools, and so on.

[0098] For indexability, the blade pockets are preferably equally angularly spaced around the outer periphery of the parting tool.

[0099] Since the present invention is more applicable to tools with space constraints, it will be understood that there is less need for such an invention for extremely large tools. However, simply increasing the tool size is problematic because CNC machines have limited space, and an increased tool size requires a larger tool holder or a larger overhang, both of which are disadvantageous. Nevertheless, to provide some perspective, in a side view of the tool, the imaginary circumscribed circle C has a diameter D that satisfies the condition: D < 90 mm, preferably D < 80 mm, more preferably D < 70 mm, and most preferably D < 60 mm.

[0100] Similarly, sharp turns are particularly applicable in the vicinity of the associated blade pockets. To provide some perspective, the blade pocket length LP can be defined from its foremost point to its rearmost point. From the foremost point, a second position (where the channel starts extending away from the first blade pocket more in a second direction than towards the first blade pocket) is within a second - position length LS, and the second - position length LS satisfies the condition: LS < 3LP, preferably LS < 2LP, and most preferably LS < 1.5LP. Alternatively defined, in a quantitative manner, the second - position length LS can satisfy the condition: LS < 15 mm, preferably LS < 10 mm, and most preferably LS < 7.5 mm.

[0101] Similarly, a constricted space for a coolant channel or coolant channels within the vicinity of the associated blade pocket can be defined as follows. From the foremost point to the nearest point of the nearest coolant channel, a nearest length LC is defined, where the nearest length LC satisfies the condition: LC < 3LP, preferably LC < 2LP, and most preferably LC < 1.5LP. Alternatively defined, in quantitative terms, the nearest length LC can satisfy the condition: LC < 15 mm, preferably LC < 10 mm, and most preferably LC < 7.5 mm.

[0102] From the nearest channel to the blade pocket to an adjacent channel, an intermediate distance LI (measured along the same line from the foremost point to the nearest point of the nearest coolant channel, but starting only on the other side of the coolant channel from the nearest point and extending to the nearest point of the adjacent channel) can satisfy the condition: LI < LP, preferably LI < 0.5LP, and most preferably LI < 0.25LP. Alternatively defined, in quantitative terms, the intermediate length LC can satisfy the condition: LI < 5 mm, preferably LI < 2.5 mm, and most preferably LI < 2.5 mm.

[0103] In the previous paragraphs, different ways (the overall size of the parting tool, channels near the blade pocket, sharp turns, etc.) have been described which serve to explain the spatial constriction of the parting tool with respect to the coolant channels.

[0104] Another way to define the constricted space relates to the indexability of the parting tool. According to any of the aspects, the indexable parting tool can be divided into imaginary sectors S. The sectors S are defined as being equal in number to the number N of blade pockets of the parting tool (S = N). The sectors are defined by specifying imaginary sector planes PS passing through the central indexing axis IA at an angular pitch equal to 360° / S, the planes being equally spaced between the blade pockets. Thus, for example, in a side view, a square parting tool having four equally spaced blade pockets at each corner will be divided by two imaginary perpendicular sector planes into four basic square sectors at each corner. Another example (which would be a triangular parting tool having three equally spaced blade pockets at each corner) will be divided into three sectors at each corner. When considering a bi-directionally indexable shape (two blade pockets), such as a conventional elongate parting tool having two equally spaced blade pockets (i.e., located at diagonally opposite pockets), there will be two sectors. However, in the latter example, a single imaginary sector plane between the two blade pockets can be drawn longitudinally along the elongation of the tool, or perpendicular to the elongation of the tool (in a side view of the major surface). In such cases, for the purposes of the present invention, the orientation of the imaginary sector plane should be chosen as an option where the sector plane extends closer to the blade pocket than would occur in an alternative orientation. The reason for all of this is that it results in a sector that is more constricted at least on one side of the blade pocket, making it more difficult for a coolant channel to extend along that side (and thus, for the present invention, more applicable). Thus, for the said conventional elongate tool, the imaginary sector plane extends parallel to the direction of elongation of the tool.

[0105] In a preferred embodiment, the inlet of the coolant channel is located in a different sector than at least one of its outlets.

[0106] In a preferred embodiment, the sharp turn (or U-turn) of the coolant channel is entirely located in the same sector as at least one of its outlets. Alternatively defined, in a preferred embodiment, the second and third positions of the coolant channel are entirely located in the same sector as at least one of its outlets. Alternatively defined, in a preferred embodiment, the significant third and fourth turns of the coolant channel are entirely located in the same sector as at least one of its outlets.

[0107] In a preferred embodiment, at least two different channels (i.e., starting at different inlets) extend side by side with each other. This is due to the available constricted area. The extensions (LE) of two substantially parallel portions of the two different channels can be at least 10% of the corresponding length of the side BLS of the tool (i.e., the length of the tool parallel to the extension of the parallel portions), such that the following condition is met: LE > 0.1LS, preferably LE > 0.3LS, and most preferably LE > 0.5LS.

[0108] The outermost channels (i.e., the channels closer to the outer peripheral edge of the tool) can then turn adjacent to a similar turn of the innermost channel (substantially in the direction towards the blade pocket, the innermost channel having an outlet associated therewith). The outermost channels can then turn again to redirect back to the blade pocket, which has an outlet channel associated therewith.

[0109] In a preferred embodiment, the imaginary diagonal line L1 intersects at least two coolant channels within the same sector as the associated blade pocket.

[0110] In a preferred embodiment, an area including at least two different coolant channels is defined in the downward direction exactly between a first imaginary downward line L2 extending from a last point and a first imaginary downward line L2 extending forward from the first imaginary downward line L2.

[0111] Regarding the force angle range θ, it will be understood that the exact direction of the force on the cutting blade changes as the cutting blade moves relative to entering the workpiece. Nevertheless, it is generally directed as defined above (i.e., between the downward direction at the foremost point and the direction towards the rearward direction, and satisfying the condition: 50° > θ > 10°). Nevertheless, the positions of at least two channels can be more accurately defined within the condition: 40° > θ > 15°, or even more accurately 30° > θ > 15°.

[0112] It will be understood that regarding the space constraint, the imaginary diagonal line L1 can preferably intersect at least three coolant channels or at least even four coolant channels.

[0113] Regarding the channels intersecting the imaginary diagonal line L1 or the first imaginary downward line L2, preferably, at least two adjacent channels extend in the same basic direction at the intersection point. In other words, preferably, at least two adjacent channels extend substantially parallel to each other in the intersection area. In other words, the adjacent channels at the intersection point can have imaginary extension lines E1, E2, which extend parallel to the coolant path at the intersection point and form an angle γ satisfying the condition: γ < 45°, preferably γ < 30°, and most preferably γ < 15°.

[0114] Although in the illustrated example there is a central hole shown for non-coolant purposes, it should be noted that although the opposite case is still an option, in a preferred embodiment, the coolant inlet is formed separately from the central hole (and thus does not open to the inner edge of the central hole).

[0115] In a preferred embodiment, the coolant channel includes a single initial channel portion which then divides into a plurality of subsequent channel portions. It will be appreciated that a single initial channel portion requires less space than two parallel channel portions and thus this configuration is preferred. Preferably, the initial channel portion has a length LCP which is greater than 20% of the total length LOC of the coolant channel from the inlet to its nearest outlet (LCP > 0.2LOC), and more preferably LCP > 0.4LOC. Nevertheless, preferably, the subsequent channel portions include terminal linear portions to properly direct the coolant. Thus, the division is preferably not extremely close to the outlet. Thus, preferably, LCP < 0.8LOC, and more preferably, LCP < 0.65LOC.

[0116] More precisely, each of the two subsequent channel members may extend from the initial channel member to at least one outlet opening. The at least one outlet opening may be a rake outlet opening into the rake side portion of the blade pocket and a clearance outlet opening into the clearance side portion of the same blade pocket. The subsequent channel portion extending to the rake outlet may be referred to as the rake channel portion. The subsequent channel portion extending to the clearance outlet may be referred to as the clearance channel portion.

[0117] Although any tool shape is possible, preferably, in a side view of the tool (e.g., Figure 3A ) the outer peripheral edge of the tool includes a straight adjacent portion for stable mounting.

[0118] Although any blade pocket is feasible, even a blade pocket using a clamp or screw, for a thin parting tool, preferably, an elastic blade pocket is used which is generally narrower than the previously mentioned types. The elastic blade pocket may be of any known configuration. Typically, each blade pocket herein may include a base jaw (i.e., located below the cutting blade, or in other words, on the side of the cutting blade opposite the rake surface of the cutting blade), and a second jaw. The second jaw illustrated in the figures herein extends behind the cutting blade and may be defined as being behind the base jaw. Another known configuration is where the second jaw is located above the base jaw.

[0119] The tool may include additional blade pockets. For example, a fourth blade pocket is positioned along the outer peripheral edge of the tool; and a fourth coolant channel forms a path leading from an associated inlet to the fourth blade pocket.

[0120] Regarding the inlets, preferably, they include inlet reservoirs which are larger in cross-section than the subsequent channel portions.

[0121] Regarding the portions of the channel adjacent to the outlet, preferably, they include terminal linear portions to ensure that the coolant continues along the desired path after leaving the tool.

[0122] Each of the above-described features associated with the first coolant passage may also apply to one or more of the other coolant passages, preferably all of the other coolant passages.

[0123] For each blade pocket, the coolant passages may be similar or identical.

[0124] Generally speaking, although any turn in the coolant passage can be measured on either side thereof (e.g., on one side, the angle may be 150°, while measured on the other side, the preferred angle will be 210°), it should be noted that all angles mentioned in the specification for the turns should be measured at the side less than 180°. BRIEF DESCRIPTION OF THE DRAWINGS

[0125] For a better understanding of the subject matter of the present application and to show how the present application may be carried out in practice, reference will now be made to the accompanying drawings, in which:

[0126] Figure 1A is a front view of a separating tool assembly according to the present invention;

[0127] Figure 1B is Figure 1A a top view of the tool assembly in

[0128] Figure 1C is Figure 1A a side view of the tool assembly in

[0129] Figure 1D is Figure 1A a bottom view of the tool assembly in

[0130] Figure 1E is Figure 1A a rear view of the tool assembly in

[0131] Figure 2A is Figure 1A a front view of the tool holder shown in

[0132] Figure 2B is Figure 2A a top view of the tool holder in

[0133] Figure 2C is Figure 2A a side view of the tool holder in

[0134] Figure 2D is Figure 2A a bottom view of the tool holder in

[0135] Figure 2E is Figure 2A a rear view of the tool holder in

[0136] Figure 3A is Figure 1A a side view of the parting tool shown in

[0137] Figure 3B is Figure 3A a front view of the parting tool shown in

[0138] Figure 4 is Figure 3B an enlarged view of the portion labeled "IV" in

[0139] Figure 5 is a corresponding enlarged view in the direction labeled "V" in Figure 3A

[0140] Figure 6 is a cross-sectional view along line VI-VI in Figure 3B (although conventional hatching lines are not shown for ease of visibility);

[0141] Figure 6B is Figure 6 a portion of the cross-sectional view shown in (although conventional hatching lines are not shown for ease of visibility); and

[0142] Figure 7 is an enlarged cross-sectional view along line VII-VII in Figure 6 DETAILED DESCRIPTION

[0143] Referring to Figures 1A to 2E , the tool assembly 10 includes a tool holder 12 and a parting tool 14 mounted to the tool holder 12 and is configured to hold a single cutting blade 16 in an enabled first blade pocket 18A (referring to Figure 3A , in this example, the parting tool 14 includes a first blade pocket 18A, a second blade pocket 18B, a third blade pocket 18C, and a fourth blade pocket 18D, where the first blade pocket 18A is the enabled blade pocket).

[0144] The tool holder 12 includes an elongated tool shank 19 having a shank axis AS that defines a forward tool direction DTF and a rearward tool direction DTR.

[0145] Perpendicular to the forward tool direction DTF and the rearward tool direction DTR are an upward tool direction DTU and a downward tool direction DTD.

[0146] Perpendicular to the forward tool direction DTF, the rearward tool direction DTR, the upward tool direction DTU, and the downward tool direction DTD are a first side tool direction DTS1 and a second side tool direction DTS2.

[0147] The tool holder 12 further includes a tool head 20, which includes a tool pocket 22 ( Figure 2C ), and the parting tool 14 is clamped in the tool pocket 22 via a first screw 24A and a second screw 24B.

[0148] The tool head 20 may also typically include a concave front surface 26. It will be understood that a workpiece (not shown) cannot be separated to a depth greater than the depth defined by the curvature of the concave front surface 26. Nevertheless, the concave front surface 26 provides structural support to the thin parting tool 14.

[0149] The tool pocket 22 includes a holder outer peripheral wall 28 (the adjacent surfaces of which are a rear wall portion 28A and a bottom wall portion 28B), which extends from the pocket side surface 30 of the tool pocket 22 in a first side tool direction DTS1.

[0150] The pocket side surface 30 is formed with a holder coolant outlet 32 for supplying coolant from the holder 12 to the tool 14.

[0151] The pocket side surface 30 may also be formed with an O-ring recess 36, a threaded seal opening 34, and an O-ring (not shown), which is installed in the O-ring recess 36 and surrounds the holder coolant outlet 32 and the seal opening 34.

[0152] Returning to Figure 1C , the threaded seal element 38 may extend through the tool 14 and be fixed in the seal opening 34 to prevent the coolant leaving the holder 12 from simply passing through the inlet of the tool (not shown in Figure 1C ).

[0153] As Figure 1A mentioned, the cutting blade 16 includes a rake face 16B and a front clearance face 16A extending downward therefrom (and side clearance faces, for example, Figure 1C one side clearance face labeled 16C shown in). Thus, the first blade pocket 18A has a rake side portion 16D, which is positioned adjacent to the rake face 16B, or alternatively defined as positioned adjacent to or above the rake face 16B. The first blade pocket 18A also has a clearance side portion 16E, which is adjacent to the front clearance face 16B, or alternatively defined as positioned below the rake face 16A.

[0154] Preferably, the cutting blade 16 is formed with a chip forming structure 16F ( Figure 1B ).

[0155] As Figure 1B mentioned, the cutting width CW of the cutting edge 40 of the cutting blade is wider than the tool width BW of the tool.

[0156] The total cutting force FC is schematically shown by the arrow on the cutting blade 16. Such force is exerted by the workpiece on the blade 16 and thus continues along the downward tool direction DTD and the backward tool direction DTR (more along the downward tool direction DTD than along the backward tool direction DTR) substantially on the tool 14.

[0157] Notably, if the structure including the retainer coolant outlet 32 extends further than the concave front surface 26 in one or both of the forward tool direction DTF and the upward tool direction DTU, this will reduce the cutting depth capacity of the tool assembly 10 because the workpiece will be obstructed by any protrusion extending beyond the concave front surface 26. Thus, preferably, the inlet for the tool 14 (e.g., Figure 3A the first inlet 58A shown) is non - centrally located. Conversely, if the shown retainer coolant outlet 32 were positioned to provide coolant to the center of the tool (not shown), the overall size of the tool would be smaller than the size shown, thereby reducing its depth capacity. It will be understood that, nevertheless, this is an option of the present invention and thus certain aspects that are not limited to non - centrally located tool inlets. Nevertheless, a non - centrally located tool inlet (spaced further from the enabled blade pockets) has the advantages mentioned above.

[0158] The above description of the tool holder 12 and the attachments (screws, seals, etc.) is similar to those described in US 2019 / 0240741, and additional details are provided there and incorporated herein by reference.

[0159] Referring to Figure 3A and Figure 3B , the exemplary features of the present invention will now be described in connection with the exemplary tool 14 shown in the figures.

[0160] The parting tool 14 includes a first side surface 42A and a second side surface 42B, and a tool outer periphery 44.

[0161] The tool outer periphery 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 a first blade pocket 18A, a second blade pocket 18B, a third blade pocket 18C, and a fourth blade pocket 18D. The maximum distance between opposite outer peripheral sub - edges defines the length of the side BLS of the tool.

[0162] Preferably, the outer peripheral sub - edges 44A, 44B, 44C, 44D include straight bearing surfaces (i.e., as shown in a side view of the parting tool such as Figure 1C ).

[0163] The exemplary parting tool 14 shown has a regular shape, in this case, the regular shape is a basic square shape. Figure 1C The imaginary circumscribed circle C shown in contacts the tool outer peripheral edge 44 of the tool 14, and the imaginary circumscribed circle C has a diameter D.

[0164] The parting tool 14 is rotationally symmetric about a central index axis AI. More precisely, the four-way indexable parting tool 14 is rotationally symmetric by ninety degrees.

[0165] Thus, for ease of explanation, the features of the coolant paths and blade pockets and all other features can be described with reference to one part of the tool (merely for ease of visibility), but it should be understood that each rotationally symmetric corresponding part also includes the same features.

[0166] However, it will be understood that while the coolant channels of this example are the same, small deviations in the paths are also possible (especially in the case of the flexibility of additive manufacturing (also known as 3D printing)), and thus, it is not important for them to be perfectly the same. Additionally, as seen in the following Figure 6 the coolant channels follow a tortuous path from their respective inlets to their respective blade pockets, and coolant is supplied to this tortuous path.

[0167] The first blade pocket 18A includes a base jaw 46, a second jaw 48, and a slot end 50.

[0168] The base jaw 46 defines a base plane PB and includes a foremost point 52 distal to the slot end 50.

[0169] A backward tool direction DBR is defined along the base plane PB from the foremost point 52 towards the tool 14. In this non-limiting example, the backward tool direction DBR more particularly directs towards that part of the tool behind the associated second jaw 48. Relative to the backward tool direction DBR, a forward tool direction DBF, an upward tool direction DBU, and a downward tool direction DBD are defined (all arbitrarily defined with respect to the first blade pocket 18A in this example).

[0170] In the backward tool direction DBR from the foremost point 52, a last point 54 is defined at the slot end 50 in this example, however, this may not be the case for different types of blade pockets.

[0171] Now referring to Figure 6 an exemplary internal coolant structure will be described.

[0172] A first coolant channel 56, a second coolant channel 58, a third coolant channel 60, and a fourth coolant channel 62 are shown.

[0173] For ease of visibility, only some features will be described with respect to the other coolant channels, but it should be understood to apply to each coolant channel.

[0174] The first coolant channel 56 includes a first inlet 56A, at least one first outlet 56B that opens into the first blade pocket 18A, and a first channel portion 56C that extends from the first inlet 56A to the at least one first outlet 56B (in this case, labeled 56B1). For clarity, the first channel portion 56C is the entire extension of the first coolant channel 56 that extends between the first inlet 56A and its at least one first outlet 56B, 56B1.

[0175] For elaboration, in the illustrated example, the at least one first outlet 56B includes a first rake outlet 56B1 that opens into the rake side portion 16D of the first blade pocket 18A, and a first clearance outlet 56B2 that opens into the clearance side portion 16E of the first blade pocket 18A.

[0176] Similarly: the second coolant channel 58 includes a second inlet 58A, at least one second outlet 58B (in this example, a second rake outlet 58B1 and a second clearance outlet 58B2) that opens into the second blade pocket 18B, and a second channel portion 58C; the third coolant channel 60 includes a third inlet 60A, at least one third outlet 60B (in this example, a third rake outlet 60B1 and a third clearance outlet 60B2) that opens into the third blade pocket 18C, and a third channel portion 60C; and the fourth coolant channel 62 includes a fourth inlet 62A, at least one fourth outlet 62B (in this example, a fourth rake outlet 62B1 and a fourth clearance outlet 62B2) that opens into the fourth blade pocket 18D, and a fourth channel portion 62C.

[0177] Back to Figure 3A, it will be understood that externally and internally, each of the first inlet 56A, the second inlet 58A, the third inlet 60A, and the fourth inlet 62A includes a pair of converging straight upper inlet edges 56D1, 56D2, 58D1, 58D2, 60D1, 60D2, 62D1, 62D2, all of which are 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. For purposes of elaborating on the direction, in this example, each pair converges in the combined upward tool direction DBU and the forward tool direction DBF. For purposes of elaboration, the first inlet 56A, the second inlet 58A, the third inlet 60A, and the fourth inlet 62A each include vertices (i.e., a first vertex 56E, a second vertex 58E, a third vertex 60E, and a fourth vertex 62E at the juncture of each pair of straight upper inlet edges 56D1, 56D2, 58D1, 58D2, 60D1, 60D2, 62D1, 62D2).

[0178] In this example, the first inlet 56A, the second inlet 58A, the third inlet 60A, and the fourth inlet 62A are four-way straight-sided polygons, and they each further include a pair of converging straight lower inlet edges 56F1, 56F2, 58F1, 58F2, 60F1, 60F2, 62F1, 62F2. 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.

[0179] It will be understood that the tool 16 is preferably printed in an orientation that is 45° from the orientation shown in FIG. 3 (i.e., during additive manufacturing), and advantageously, any of the first blade pocket 18A, the second blade pocket 18B, the third blade pocket 18C, and the fourth blade pocket 18D can be the uppermost blade pocket during printing.

[0180] For use as an example, the first inlet 56A of the first coolant passage is positioned further from the furthest point 52 of the first blade pocket 18A than the central indexing axis AI (the length from the furthest point 52 to the central indexing axis AI is labeled LD1). This allows for a greater cutting depth for the tool 14 compared to the case where the first tool inlet 56A is located at the central indexing axis AI, and in the latter case, the maximum separation depth (as limited by the retainer 12) would have a length LD1 (or even less, since the tool inlet has an area). In the example shown, the separation depth is closer to the length LD2 (although slightly less due to the structure of the retainer 12; the length from the furthest point 52 to the first inlet 56A is labeled LD2). In any case, the separation depth capability of the tool 14 is greater than the length LD1.

[0181] Similarly, it will be noted that the first inlet 56A is positioned further from the furthest point 52 of the first blade pocket 18A than the second inlet 58A, i.e., the second inlet 58A is closer to the furthest point 52 than the first inlet 56A. This allows for the same advantage of a greater depth (the length LD3 from the furthest point 52 to the second inlet 58A is significantly less than the possible separation depth for the tool 14) as described above, but such a structure provides yet another advantage of the nested coolant passage arrangement shown (i.e., the passages surround each other to reach the desired blade pockets without being blocked by another coolant passage). In fact, as Figure 3A can be seen, the first inlet 56A is further from the furthest point 52 of the first blade pocket 18A than all the other inlets 58A, 60A, 62A.

[0182] Now returning to Figure 6 , the first coolant passage 56 extends in a clockwise direction so as to surround at least a portion of the outer side of the second coolant passage 58. Similarly, the second coolant passage 58 extends in a clockwise direction so as to surround the outer side of the third coolant passage 60, and so on. Thus, as Figure 6B can be seen, in a cross-section of the tool taken between the first side surface 42A and the second side surface 42B, any imaginary radial line LR extending from the central axis A1 to any part of the outer periphery 44 of the tool intersects at least two of the coolant passages. As mentioned above, the surrounding or nesting can alternatively be in the counterclockwise direction.

[0183] Also referring to Figure 6B , using the fourth coolant passage 62 as an example, it will be noted that the fourth passage portion 62C can include a single initial passage portion 62G that divides into a plurality of subsequent passage portions 62H (the subsequent passage portions in this example include a first subsequent passage portion 62H1 connected to the fourth rake outlet 62B1 and a second subsequent passage portion 62H2 connected to the fourth relief outlet 62B2).

[0184] The initial channel portion 62G has a length LCP (measured from the edge of the fourth inlet 62A to the start of the first bend T1 of the fourth channel portion 62C). Notably and advantageously, the length LCP of the initial channel portion is very significantly long because the alternative of having two parallel channels (not shown) fitting in the same crowded area would be relatively more problematic in the available constricted space (i.e., if there would be completely separate channels from the fourth inlet 62A to the respective fourth front tool outlet 62B1 and fourth clearance outlet 62B2).

[0185] Nonetheless, to supply coolant to both sides of the fourth blade pocket, the fourth channel portion 62C is divided into the two subsequent channel portions 62H1, 62H2.

[0186] The shorter of the two subsequent channel portions 62H (which is the first subsequent channel portion 62H1 in this instance) defines a length LOC, which is schematically shown as the sum of a first length LOC1 of the first subsequent channel portion and a second length LOC2 of the first subsequent channel portion.

[0187] It will also be noted that, advantageously, both the first subsequent channel portion 62H1 and the second subsequent channel portion 62H2 have respective first terminal linear portions 62I1 and second terminal linear portions 62I2, which are adjacent to the fourth front tool outlet 62B1 and the fourth clearance outlet 62B2 and open towards the fourth front tool outlet 62B1 and the fourth clearance outlet 62B2.

[0188] Now also referring to Figure 6 , regarding the passage path of the fourth coolant channel 62 (generally labeled "62J"), first note that the initial channel portion 62G extends from a first position 62K1 proximal to the fourth inlet 62A (considering the main basic path of the initial channel portion 62G, rather than a minor portion 62K3 that departs from the fourth inlet 62A and extends in a slightly different direction ( Figure 6B )) along a first direction D1, which is more towards the fourth blade pocket 18D than away from the fourth blade pocket 18D. For clarity, the first direction D1 extends in a combination of the backward tool direction DBR and the upward tool direction DBU.

[0189] Regarding the first subsequent channel portion 62H1 of the fourth coolant channel, at the location where the initial channel portion 62G divides into the two subsequent channel portions 62H1, 62H2, there is a significant first bend T1 of the fourth coolant channel 62. Herein, a "significant bend" between two adjacent sections of the coolant path is a bend that undergoes at least a 25° turn (i.e., ≥25°).

[0190] At the prominent first turn T1, the first subsequent channel portion 62H1 of the fourth coolant channel has a non-sharp turn (i.e., the turn is greater than 90°, even greater than 110°, and in this instance, forms a first channel portion first angle μ1 of 123°, as measured using the dashed line drawn through the straight portion of the fourth channel portion 62C and adjacent straight lines, and the upcoming angles will be measured in a similar manner), and a second smaller turn leading to the first terminal linear portion 62I1 (in this instance, the second channel portion second angle μ2 = 155°).

[0191] More notably, at the prominent first turn T1 of the fourth coolant channel 62, with respect to the second subsequent channel portion 62H2 of the fourth coolant channel (which is a channel portion that is positioned farther from the fourth outer peripheral sub-edge 44D of the tool than the first subsequent channel portion 62H1), the prominent first turn T1 is sharper (i.e., the turn is much less than 110°, even less than 100°, and in this instance, forms a first angle α1 of the second channel portion of 96°).

[0192] It will be understood that since the first angle α1 of the channel portion is less than the first angle μ1 of the first channel portion, this will cause the pressure drop in the second subsequent channel portion 62H2 to be relatively greater than the pressure drop in the first subsequent channel portion 62H1.

[0193] Notably, the second subsequent channel portion 62H2 has a first sub-channel portion 62L that is adjacent to and extends parallel to the initial channel portion 58G of the first coolant channel.

[0194] The first sub-channel portion 62L of the fourth coolant channel and the initial channel portion 58G of the first coolant channel are adjacent to each other and extend parallel to each other for a significant length (referred to herein as "extension LE" (shown in Figure 6 ), and measured along the positions where the two portions are parallel).

[0195] Subsequently, at a second location 62K2 that also includes a prominent second turn T2 of the fourth coolant channel (when considering the continuous coolant path along the second subsequent channel portion 62H2), the channel path extends more away from the fourth blade pocket 18D than towards the fourth blade pocket 18D in a second direction D2. For clarity, the second direction D2 extends in a combination of the forward tool direction DBF and the upward tool direction DBU. At this location, there is a prominent second turn T2, at which the second angle α2 of the channel portion is 139°.

[0196] Subsequently, at a third position 62K3 of a sharp third turn T3 that further includes a fourth coolant passage 62, the passage path extends more in a third direction D3 towards the fourth blade pocket 18D than away from the fourth blade pocket 18D. A sharp turn acute angle α0 is formed between a straight portion immediately after a second position 62K2 and a straight portion after the third position 62K3, and constitutes an extremely sharp turn T3 having an acute angle α0 of 42°.

[0197] An alternative definition of the sharp turn angle (which briefly refers to the corresponding part of the second coolant passage) can be defined according to the radius R ( Figure 6 ; for ease of visibility, labeled adjacent to the second clearance outlet 58B2), rather than using the dashed line.

[0198] For ease of visibility, the description of the same structure will now continue with reference to a second subsequent passage 60H2 of the third coolant passage 60, as Figure 6B shown in the lower left corner of. To compensate for the extremely sharp turn T3, an enlarged cross-section of the second subsequent passage 60H2 is shown in the region between a second position 60K2 and a third position 60K3, and is labeled 60M1 (in this instance, the shown region is a curved turn 60M1 between the second position 60K2 and the third position 60K3).

[0199] More precisely, the curved turn 60M1 is preceded by a preceding passage portion 60M2 and followed by a subsequent passage portion 60M3, the latter two portions being straight.

[0200] Returning to the fourth coolant passage 62 as shown in Figure 6 , differently defining the third turn T3, the so-called "sharp turn" can be considered as two adjacent significant sub-turns (i.e., a first sub-turn T3A and a second sub-turn T3B).

[0201] The first sub-turn T3A has a third channel angle α3 of 125°.

[0202] The second sub-turn T3B has a fourth channel angle α4 of 100°.

[0203] For ease of visibility, the description will continue with reference to Figure 6 the region of the second blade pocket 18B in. To provide a perspective view of the third sharp turn T3 close to the blade pocket (which briefly refers to the second blade pocket 18B and the second coolant passage 58 adjacent thereto), it can be noted that the sharp turn starts at a second position 58K2 (or the second turn T2). The distances of the blade pocket length LP and the second position length LS measured from the foremost point 52 to the second position 62K2 are relatively similar (relatively similar means that the second position length LS is less than twice the magnitude of the blade pocket length LP).

[0204] Similarly, the close alternative limit may be the closest length LC, which is between the foremost point 52 and the closest point 58N of the closest coolant passage (which is the second subsequent passage portion 58H2 of the second coolant passage in the illustrated example).

[0205] The first intermediate distance LI1 (along the line shown as extending to the closest point 58N) between the two coolant passages closest to the second blade pocket 18B is shown and is 0.8 mm.

[0206] The second intermediate distance LI2 between the second closest coolant passage (which is the single initial passage portion 60G of the third coolant outlet in the illustrated example) and the third closest coolant passage (which is the single initial passage portion 62G of the fourth coolant outlet in the illustrated example) is shown and is 1 mm.

[0207] In other words, the distance between adjacent coolant passages is approximately equal to or less than the cross-sectional dimension of the coolant passages themselves. In other words, the coolant passages are positioned closely relative to each other.

[0208] As Figure 1C best seen in, the parting tool 14 can be divided into equal sectors, specifically, in this example, a first sector S1, a second sector S2, a third sector S3, and a fourth sector S4, which can be considered "quadrants" in this example.

[0209] Now referring Figure 6 to the first coolant passage 56, whose first inlet 56A is located in the third sector S3, it will be noted that its entire sharp turn is within the first sector S1.

[0210] Notably, the third inlet 60A is also within the first sector S1, whereas the third outlet 60B is in the third sector S3.

[0211] The force angle range θ (which has a vertex at the foremost point 52) is illustrated with respect to the first blade pocket 18A.

[0212] The force applied from the workpiece during its machining is first transmitted to the cutting blade( Figure 1C ), and then to the blade pocket. Since the exact direction of the force changes due to various variables, the defined force angle range is an approximation, which is used for the purpose of showing the forces on the tool 14.

[0213] In Figure 6In this case, a hypothetical diagonal line L1 is drawn from the foremost point 52 and within the force angle range θ to show its intersection with three coolant channels, namely, the second subsequent channel portion 56H2 of the first coolant channel, the initial channel portion 58G of the second coolant channel, and the initial channel portion 60G of the third coolant channel. As further shown along these intersecting coolant channels, a first hypothetical extension line E1 extends through the second subsequent channel portion 56H2 of the first coolant channel, and a second hypothetical extension line E2 extends through the initial channel portion 58G of the second coolant channel. The first extension line E1 and the second extension line E2 are drawn to extend parallel to their respective coolant paths at the intersection point of the diagonal line L1, and an extension line angle γ is seen to be formed between them.

[0214] Returning to the region 58L shown, for example, with respect to the second blade pocket 18B, the region 58L is defined between a first hypothetical downward line L2 and the rearmost point 54. When considering the region in the exact downward direction therebetween (and of course with respect to the blade pocket, noting that the downward direction shown in this figure for the second blade pocket 18B is the indicated rearward tool direction DBR), in this instance, the region 58L includes two coolant channels (i.e., the second subsequent channel portion 58H2 of the second coolant channel and the first subsequent channel portion 60H1 of the third coolant channel) within the defined region.

[0215] Referring to Figure 7 , a first cross-sectional shape 64 of the second coolant channel 58 along its initial channel portion 58G is shown.

[0216] In addition, a second cross-sectional shape 66 of the first coolant channel 56 along its second subsequent channel portion 56H2 is shown.

[0217] Regarding the first cross-sectional shape 64, it includes: opposite first side edge 64A and second side edge 64B; a first straight upper edge 64C that extends from the first side edge 64A within the channel portion at a first obtuse angle β1; a second straight upper edge 64D that extends from the second side edge 64B within the channel portion at a second obtuse angle β2; a first straight lower edge 64E that extends from the opposite side of the first side edge 64A within the channel portion at a third obtuse angle β3; a second straight lower edge 64F that extends from the opposite side of the second side edge 64B within the channel portion at a fourth obtuse angle β4; the first upper edge 64C and the second upper edge 64D that are connected at the upper corner edge 64G of the concave shape; and the first lower edge 64E and the second lower edge 64F that are connected at the lower corner edge 64H of the concave shape.

[0218] Notably, while both the first side edges 64A and the second side edges 64B are longer than each of the first upper edges 64C and the second upper edges 64D, for the first cross-sectional shape, the first side edges 66A and the second side edges 66B of the second cross-sectional shape 66 are substantially the same length as the first upper edge 66C and the second upper edge 66D of the second cross-sectional shape. While a more elongated shape would be preferred for coolant flow, due to space constraints, such a more elongated shape is not provided. It will be understood that the cross-sections of the first cross-sectional shape 64 and the second cross-sectional shape 66 may be interchanged. However, preferably, the initial channel portion of the coolant channel has a larger cross-sectional area than the plurality of subsequent channel portions, as the coolant will be split between the subsequent channel portions.

[0219] Both the first cross-sectional shape 64 and the second cross-sectional shape 66 are elongated in the tool-upward direction DBU and the tool-downward direction DBD.

[0220] The first cross-sectional shape 64 is mirror-symmetrical about a first intermediate plane PM1 that is perpendicular to and extends through the midpoints of the first side edge 42A and the second side edge 42B of the tool.

[0221] The first cross-sectional shape 64 (and the second cross-sectional shape 66) is mirror-symmetrical about a second intermediate plane PM2 that is parallel to and extends through the midpoints of the first side edge 42A and the second side edge 42B of the tool.

[0222] Returning to Figure 4 , it will be noted that the first rake exit 56B1 is reduced to a substantially square shape (rotated 45° with respect to the upward direction DBU and the downward direction DBD and thus also referred to as a "diamond shape") in terms of the previously elongated cross-sectional area. While there is a more elongated space for the first rake exit, thereby desirably increasing the cross-sectional area, the less elongated exit allows for greater structural strength in the region above it (note the significant provision 68 of material above the first rake exit 56B1).

[0223] Alternatively, to provide a similar strength, at the first relief exit 56B2 shown in Figure 5 , its shape remains elongated to provide a significant cross-sectional area and thus coolant flow. However, an elongated diamond shape is provided. In other words, the first relief exit 56B2 now includes a first side edge 70A and a second side edge 70B that are shorter than the previous first cross-sectional shape 64 near the start of the first coolant channel 58 (which are substantially concave-curved side edges), as shown in Figure 7As shown in. Similarly, this shortening is used to provide greater structural strength at the area above it, but provides additional coolant flow. To describe the diamond shape of the first clearance outlet, the first clearance outlet 56B2 includes a first side edge 70A and a second side edge 70B that are shorter than the first upper edge 70C and the second upper edge 70D, and a first side edge 70A and a second side edge 70B that are shorter than the first lower edge 70E and the second lower edge 70F. In such cases, it is preferred that the first obtuse angle β5, the second obtuse angle β6, the third obtuse angle β7, and the fourth obtuse angle β8 all fall within 120°

Claims

1. An indexable parting tool, comprising: opposite first and second tool sides; a tool outer periphery connecting the first and second tool sides; a central index axis extending through the centers of the first and second tool sides; a first insert pocket, a second insert pocket, and a third insert pocket positioned along the tool outer periphery; and a first coolant passage, a second coolant passage, and a third coolant passage; the first coolant passage including 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 including 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; and the third coolant passage including 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; wherein: the at least one first outlet includes a first rake outlet opening into a rake side portion of the first insert pocket and a first relief outlet opening into a relief side portion of the first insert pocket; and the first inlet is positioned farther from a farthest point of the first insert pocket than at least one of the second inlet and the central index axis.

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

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

4. The indexable parting tool according to claim 1, wherein, The first inlet is positioned farther from the farthest point of the first insert pocket than all other inlets of the parting tool.

5. The indexable parting tool according to claim 1, wherein, The passage path of the first passage portion includes: a first position proximal to the first inlet, where the passage path extends in a first direction that is more toward the first insert pocket than away from the first insert pocket; a second position farther from the first inlet along the passage path than the first position, where the passage path extends in a second direction more away from the first insert pocket than toward the first insert pocket; and a third position farther from the first inlet along the passage path than the second position, where the passage path extends in a third direction more toward the first insert pocket than away from the first insert pocket.

6. The indexable parting tool according to claim 1, wherein, At least the first coolant passage undergoes a sharp turn proximal to the opening of the first relief outlet, the sharp turn defining a turning acute angle α0.

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

8. The indexable parting tool according to claim 6, wherein, The sharp turn has a radius of curvature R satisfying the condition R < 5 mm.

9. The indexable parting tool according to claim 1, wherein, All passages of the parting tool 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.

10. The indexable parting tool according to claim 1, wherein, The passage path of the first passage portion includes: A first significant turn that forms a first corner α1 of a channel portion satisfying the condition: 25° < α1 < 155°; A second significant turn that forms a second corner α2 of a channel portion satisfying the condition: 25° < α2 < 155°; A third significant turn that forms a third corner α3 of a channel portion satisfying the condition: 25° < α3 < 155°; and A fourth significant turn that forms a fourth corner α4 of a channel portion satisfying the condition: 25° < α4 < 155°, where: Along the channel path, the second significant turn is downstream of the first significant turn, the third significant turn is downstream of the second significant turn, and the fourth significant turn is downstream of the third significant turn.

11. The indexable parting tool according to claim 10, wherein, The first corner α1 of the channel portion satisfies the condition: 70° < α1 < 130°.

12. The indexable parting tool according to claim 10, wherein, The second corner α2 of the channel portion satisfies the condition: 110° < α2 < 155°.

13. The indexable parting tool according to claim 10, wherein, The third corner α3 of the channel portion satisfies the condition: 90° < α3 < 155°.

14. The indexable parting tool according to claim 10, wherein, The fourth corner α4 of the channel portion satisfies the condition: 70° < α4 < 130°.

15. The indexable parting tool according to claim 1, wherein: The first blade pocket includes a base jaw, a second jaw opposite the base jaw, and a slot end connecting the base jaw and the second jaw; the base jaw defines a base plane and has a foremost point distal to the slot end; The base plane defines: a backward direction that is defined from the foremost point toward the tool; A forward direction that is opposite to the backward direction; An upward direction that is perpendicular to the forward direction and the backward direction and away from the base jaw and the tool; And a downward direction that is opposite to the upward direction; and where: a force angle range θ has a vertex at the foremost point and is defined between the downward direction and the backward direction and satisfies the condition: 50° > θ > 10°; and a hypothetical diagonal line L1 extending from the foremost point within the force angle range θ intersects at least two coolant channels.

16. The indexable parting tool according to claim 1, wherein: The first blade pocket includes a base jaw, a second jaw opposite the base jaw, and a slot end connecting the base jaw and the second jaw; the base jaw defines a base plane and has a foremost point distal to the slot end; The base plane defines: a backward direction that is defined from the foremost point toward the tool; A forward direction that is opposite to the backward direction; An upward direction that is perpendicular to the forward direction and the backward direction and away from the base jaw and the tool; And a downward direction that is opposite to the upward direction; and where: the first blade pocket has a last point; and exactly in the downward direction between the first hypothetical downward line L2 extending from the last point and in front of the first hypothetical downward line L2, a region including at least two different coolant channels is defined.

17. The indexable parting tool according to claim 1, wherein: At least a portion of the first channel portion has a cross-sectional shape that includes: opposite first and second side edges that extend along the first and second sides of the tool; a first straight upper edge that extends from the first side edge within the channel portion at a first obtuse angle β1; a second straight upper edge that extends from the second side edge within the channel portion at a second obtuse angle β2; a first straight lower edge that extends from the opposite side of the first side edge within the channel portion at a third obtuse angle β3 to the first straight upper edge; and a second straight lower edge that extends from the opposite side of the second side edge within the channel portion at a fourth obtuse angle β4 to the second straight upper edge; wherein: the first straight upper edge and the second straight upper edge are connected at an upper corner edge; and the first straight lower edge and the second straight lower edge are connected at a lower corner edge.

18. The indexable parting tool according to claim 1, wherein: the first inlet, the second inlet, and the third inlet open to one or both of the first and second sides of the tool; and each inlet includes a pair of converging straight upper inlet edges, all of which are oriented in the same direction.

19. The indexable parting tool according to claim 1, wherein: the first channel portion includes a curved turn that is preceded by a preceding channel portion and followed by a succeeding channel portion; the cross-sectional area of the turn, measured perpendicular to the coolant path through the curved turn, is greater than the cross-sectional area of the preceding channel portion, measured perpendicular to the coolant path through the preceding channel portion.

20. The indexable parting tool according to claim 1, the indexable parting tool further comprising: a fourth blade pocket that is positioned along the outer peripheral edge of the tool; and a fourth coolant channel that includes a fourth inlet, at least one fourth outlet that opens to the fourth blade pocket, and a fourth channel portion that extends between the fourth inlet and the at least one fourth outlet.

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