Additive manufactured cutting tool and method of production thereof

Abstract

An additive-manufactured cutting tool including a shank portion having an axis extending through the center thereof, an end cutting portion including at least one cutting pocket, and an intermediary portion connects the shank portion and the end cutting portion. The axis defines an upward direction DU directed from the end cutting portion towards the shank portion. The shank portion, end cutting portion and intermediary portion having a unitary monolithic construction and the intermediary portion has an upwardly-directed build construction.

Description

ADDITIVE MANUFACTURED CUTTING TOOL AND METHOD OF PRODUCTIONTHEREOFFIELD OF THE INVENTION

[0001] The subject matter of the present application relates to a cutting tool produced in at least an initial stage, by additive manufacturing (which may also be referred to herein as "printing"), and a method of production of the cutting tool.BACKGROUND OF THE INVENTION

[0002] Additive manufacturing is a rapidly improving manufacturing method. Advantages in cutting tool production include the possibility to produce lighter or reduced- weight cutting tools.

[0003] However, additive manufacturing processes are still unable to produce surfaces with the same level of high precision as some subtractive machining methods.

[0004] Additionally, some additive manufacturing methods require technological support structures to be subtractively machined away after the cutting tool has been printed. Similarly, the cutting tool itself typically needs a machining operation to be separated from a build surface upon which it has been printed. These costly operations are in addition to the above-mentioned post machining operations needed to bring surfaces which require high precision into an appropriate size and tolerance.

[0005] A further complication is that the material used for printing is often expensive and the printing itself is relatively slow, all adding to the expense of additive manufactured cutting tools.

[0006] Nonetheless, due to the capability of additive manufacturing to produce cutting tools having special shapes (e.g. allowing reduced weight or being difficult to manufacture with other methods), this remains a viable production option.

[0007] One way to offset the above-mentioned difficulties and expenses is so-called hybrid manufacturing in which a pre-manufactured precision shank portion is connected to a build surface and an additive manufacturing operation builds on top of the shank portion to produce a cutting tool. The shank portion is then separated from the build surface and held in a turret or by an adaptor etc. and the printed side of the cutting tool is machined in a subtractive manufacturing operation to produce the precision surfaces typically needed for, e.g., the metal cutting industry.

[0008] Yet another method to offset the above-mentioned difficulties is to produce a portion of a cutting tool, separate it from a build surface and connect it, e.g. via brazing or welding, to a premanufactured shank.

[0009] It is an object of the present invention to provide an improved additive manufactured cutting tool and method of producing same, which reduces the amount of subtractive postmachining required relative to known production methods. A separate but similar goal of the present invention is to reduce the material of such tools (and accordingly the weight), thereby requiring less expensive material for printing.SUMMARY OF THE INVENTION

[0010] In accordance with a first aspect of the subject matter of the present application, there is provided an additive-manufactured cutting tool comprising: a shank portion having an axis A extending through the center thereof, a shank circumscribed diameter CS, and a shank length LS parallel to the axis; an end cutting portion in turn comprising at least one cutting pocket, the end cutting portion having a cutting length LE parallel to the axis and an end circumscribed diameter CE; and an intermediary portion connecting the shank portion and the end cutting portion, and has an intermediary length LI parallel to the axis, an intermediary minimum circumscribed diameter CI2 and an intermediary maximum circumscribed diameter CI1; the axis A defining: an upward direction DU directed from the end cutting portion towards the shank portion; a downward direction DD opposite to the upward direction; a radially-outward direction DO directed away from the axis; and a radially-inward direction DI opposite to the radially-outward direction; the cutting tool has a tool length LT parallel to the axis A; the shank portion, end cutting portion and intermediary portion having a unitary monolithic construction; wherein: the intermediary portion has an upwardly-directed build construction.

[0011] Contrary to the advantageous method of hybrid printing with a pre-manufactured shank, it has been found that a different printing method has significant advantages. Namely, a cutting tool having a unitary monolithic construction is printed, including a shank portion, with the shank portion being distally located from the build surface. The position of the shank portion allows it to be machined in a precise subtractive manufacturing operation while the cutting tool is still connected to the build surface. The precisely manufactured shank portion can then be immediatelyused to hold the cutting tool after separation from the build surface to machine an end cutting portion or other areas of the cutting tool.

[0012] This may seem counterintuitive for a number of reasons (expense, production time, additional material removal from pockets which could have been produced in an upwardly directed orientation, etc.). However, these disadvantages are believed offset by the provision of a monolithic unitary construction also allows an overall weight reduction with a rigid body providing a beneficial long-overhang (i.e. an elongated length) tool without requiring precision placement of shank portions on build surfaces or precision post-connection of shank portions to printed portions.

[0013] Cutting tools produced in the above manner have a visible upwardly directed build construction at least for the intermediary portion (since the shank portion and end cutting portion may be subsequently machined and thus the direction of printing may not be clear).

[0014] An upwardly directed build construction means that the construction is either horizontal for a very short overhang distance (i.e. forming an apex which descends after a short distance to a second supported area; but not an elongated overhang shape) or preferably greater than horizontal in the upward direction, with increasing angles having better quality and overhang distance. Thus, the directionality of the structure itself indicates to a skilled person the construction direction. For example, a typical perforation shape for reducing printing is a so-called teardrop or pear shape which narrows towards the upward direction.

[0015] It will be understood that any shank portion design, and obviously known shank portion designs may be used (e.g. cylindrical, Capto TM, square shank etc.)

[0016] In accordance with a second aspect of the subject matter of the present application, there is provided a method of producing an additive manufactured cutting tool comprising the steps: (a) using an upwardly-directed build construction additive manufacturing process to produce an end cutting portion on a build surface; (b) continuing the additive manufacturing process to produce an intermediary portion on the end cutting portion; (c) continuing the additive manufacturing process to produce a shank portion on the intermediary portion; and (d) using a subtractive manufacturing process on the shank portion prior to detachment of the cutting tool from the build surface.

[0017] Preferably, the method further includes a step, subsequent to step d), wherein an additional subtractive manufacturing process is carried out on the end cutting portion only, such that subtractive manufacturing processes are only carried out on the shank portion and the endcutting portion. It will be understood that, said differently, there are no subtractive manufacturing processes carried out on the intermediary portion. Notably, subtractive manufacturing processes for the purposes of this application means chip removal processes such as milling, drilling or turning (notably polishing, sand-blasting, tumbling and similar light post-machining processes are not chip-removal processes).

[0018] In accordance with a third aspect of the subject matter of the present application, there is provided an additive-manufactured cutting tool comprising: a shank portion having an axis A extending through the center thereof, a shank circumscribed diameter CS, and a shank length LS parallel to the axis; an end cutting portion in turn comprising at least one cutting pocket, the end cutting portion having a cutting length LE parallel to the axis and an end circumscribed diameter CE; and an intermediary portion connects the shank portion and the end cutting portion, and has an intermediary length LI parallel to the axis, an intermediary minimum circumscribed diameter CI2 and an intermediary maximum circumscribed diameter CI1; the axis A defining: an upward direction DU directed from the end cutting portion towards the shank portion; a downward direction DD opposite to the upward direction; a radially-outward direction DO directed away from the axis; and a radially-inward direction DI opposite to the radially-outward direction; the cutting tool has a tool length LT parallel to the axis A; the shank portion, end cutting portion and intermediary portion having a unitary monolithic construction; wherein the only cutting pockets of the cutting tool are said at least one cutting pocket located at the end cutting portion; the intermediary length LI fulfills at least one of the conditions: (a) LI > 2LE; (b) LI > LS; and (c) the shank portion comprises upwardly directed fastener slots or holes, and the tool length LT fulfills the condition: LT > 0.8CE.

[0019] It will be understood that the cutting tool of the present aspect may advantageously have the features of or be produced in accordance with the previous aspects but is not limited thereto and may be produced in accordance with other methods for the independent advantages below.

[0020] This aspect differs from known cutting tools having cutting portions only at an end cutting portion in that it has an elongated intermediary portion. It will be understood, though, that this definition does not require the cutting tool to be a face-mill (with the cutting pockets designed for cutting inserts or cutting elements that only work axially). Lor example, the cutting tool could be a reamer or internal boring tool with the cutting inserts or cutting elements designed to workradially, and accordingly some embodiments may have designs where there may be some material further downward of the cutting pocket or pockets preventing a face milling operation.

[0021] Traditionally, cutting heads, and especially milling heads, even those which are not printed, are significantly shorter in length than their cutting diameters. If additional length is required, an extender is used. Production of a short milling head is particularly advantageous for additive manufacturing in reducing expense, and production time.

[0022] Nonetheless, it was found that for an overriding advantage of reduced weight, these disadvantages were offset by provision of a unitary monolithic construction with an elongated intermediary portion.

[0023] In this particular aspect, the intermediary portion is devoid of cutting pockets (i.e. the elongation thereof is not for functional purposes by providing cutting pockets along the side of the cutting tool), in difference to other cutting tools which are elongated but for the purpose of providing shouldering operations with multiple inserts, for example shell mill cutters with multiple inserts along a single flute. It will be understood that other aspects of the present invention which are not so restricted ("the only cutting pockets of the cutting tool are said at least one cutting pocket located at the end cutting portion") are envisioned that they may, in some embodiments, have cutting pockets along the intermediary portion thereof.

[0024] It will be understood that each condition above by itself or in combination with the other preferred conditions is advantageous. Accordingly, it is preferable, wherein both conditions a) and b) are fulfilled, or when both conditions a) and c) are fulfilled; or when both conditions b) and c) are fulfilled; or when all three conditions, a) b) and c) are fulfilled.

[0025] In accordance with a fourth aspect of the subject matter of the present application, there is provided an additive-manufactured cutting tool comprising: a shank portion having an axis A extending through the center thereof, a shank circumscribed diameter CS, and a shank length LS parallel to the axis; an end cutting portion in turn comprising at least one cutting pocket, the end cutting portion having a cutting length LE parallel to the axis and an end circumscribed diameter CE; and an intermediary portion connects the shank portion and the end cutting portion, and has an intermediary length LI parallel to the axis, an intermediary minimum circumscribed diameter CI2 and an intermediary maximum circumscribed diameter CI1; the axis A defining: an upward direction DU directed from the end cutting portion towards the shank portion; a downward direction DD opposite to the upward direction; a radially-outward direction DO directed awayfrom the axis; and a radially-inward direction DI opposite to the radially-outward direction; the cutting tool has a tool length LT parallel to the axis A; the shank portion, end cutting portion and intermediary portion having a unitary monolithic construction; wherein the intermediary portion is perforated.

[0026] It will be understood that the cutting tool of the present aspect may advantageously have the features of or be produced in accordance with the previous aspects but is not limited thereto and may be produced in accordance with other methods for the independent advantages below.

[0027] By providing the intermediary portion with perforations, the weight of the cutting tool can be reduced even further.

[0028] In accordance with a fifth aspect of the subject matter of the present application, there is provided an additive-manufactured cutting tool comprising: a shank portion having an axis A extending through the center thereof, a shank circumscribed diameter CS, and a shank length LS parallel to the axis; an end cutting portion in turn comprising at least one cutting pocket, the end cutting portion having a cutting length LE parallel to the axis and an end circumscribed diameter CE; and an intermediary portion connects the shank portion and the end cutting portion, and has an intermediary length LI parallel to the axis, an intermediary minimum circumscribed diameter CI2 and an intermediary maximum circumscribed diameter CI1; the axis A defining: an upward direction DU directed from the end cutting portion towards the shank portion; a downward direction DD opposite to the upward direction; a radially-outward direction DO directed away from the axis; and a radially-inward direction DI opposite to the radially-outward direction; the cutting tool has a tool length LT parallel to the axis A; the shank portion, end cutting portion and intermediary portion having a unitary monolithic construction; wherein: the cutting tool has a central cavity extending parallel with the axis A from at least the intermediary portion in the downward direction DD and opening out in the downward direction DD; and the cutting tool has a hourglass shape such that the shank circumscribed diameter CS is greater than a first diameter D 1 of a first cross-section perpendicular to the axis A at the intermediary portion proximate to the shank portion; and a second diameter D2 at a second cross-section perpendicular to the axis A at the intermediary portion and closer to the end cutting portion than the first cross-section, fulfills the condition D2 > D 1.

[0029] It will be understood that the cutting tool of the present aspect may advantageously have the features of or be produced in accordance with the previous aspects but is not limited thereto and may be produced in accordance with other methods for the independent advantages below.

[0030] This aspect provides an advantageous construction particularly beneficial to a cutting tool produced with an upwardly-directed build construction. Since the cutting tool in question has a central cavity when printing towards a shank portion distal from a build surface support must be provided for the center of the shank portion. To achieve this, a central support can simply be built from a build surface and then subsequently removed in a subtractive manufacturing process. According to the present aspect, this central support and a step of removal thereof can be avoided by providing the cutting tool with the so-called hourglass shape. This shape allows material to reach a suitable position where an upward and outward built structure can provide support for the outermost portion of the shank portion and simultaneously there is sufficient support for an upward and inward build structure to produce the inner lower portion of the shank portion.

[0031] In summary, this aspect provides an advantageous construction avoiding the need for additional printing of a support and removal of the support subsequently.

[0032] Preferably, a diameter of the cutting tool increases continuously from a first cross-section to a second cross-section (the second cross-section being closer to the end cutting portion).

[0033] Preferably, a diameter of the cutting tool decreases continuously from the shank circumscribed diameter CS to the first cross-section.

[0034] It will be understood that continuous changes in diameter require less technological supports that require removal subsequent to printing.

[0035] In accordance with a sixth aspect of the subject matter of the present application, there is provided an additive-manufactured cutting tool comprising: a shank portion having an axis A extending through the center thereof, a shank circumscribed diameter CS, and a shank length LS parallel to the axis; an end cutting portion in turn comprising at least one cutting pocket, the end cutting portion having a cutting length LE parallel to the axis and an end circumscribed diameter CE; and an intermediary portion connects the shank portion and the end cutting portion, and has an intermediary length LI parallel to the axis, an intermediary minimum circumscribed diameter CI2 and an intermediary maximum circumscribed diameter CI1; the axis A defining: an upward direction DU directed from the end cutting portion towards the shank portion; a downward direction DD opposite to the upward direction; a radially-outward direction DO directed awayfrom the axis; and a radially-inward direction DI opposite to the radially-outward direction; the cutting tool has a tool length LT parallel to the axis A; the shank portion, end cutting portion and intermediary portion having a unitary monolithic construction; wherein: the cutting tool has a central cavity extending parallel with the axis A from at least the intermediary portion in the downward direction DD and opening out in the downward direction DD; and the central cavity comprises a cavity top surface which tapers in the upward direction DU.

[0036] It will be understood that the cutting tool of the present aspect may advantageously have the features of or be produced in accordance with the previous aspects but is not limited thereto and may be produced in accordance with other methods for the independent advantages below.

[0037] This aspect further advances the previous aspect by providing an advantageous design for a cavity top surface.

[0038] In accordance with a seventh aspect of the subject matter of the present application, there is provided a cutting tool comprising: a shank portion comprising external upwardly directed fastener slots having neck portions.

[0039] More precisely the cutting tool can be an additive -manufactured cutting tool having any of the features of the other aspects, but it should be understood that the shank portion developed for the present additive-manufactured cutting tool is also believed to be beneficial even for tools manufactured in other methods because it allows sideways insertion of shank screws, freeing up more area of an intermediary portion directly adjacent to a shank portion.

[0040] Despite more area being free, it is still preferable for an intermediary portion to have a transition sub-section adjacent to the shank portion which transitions inwardly to a central subsection. Both of these sub-sections are essentially configured to provide space (i.e. to be "relieved" in cutting tool terminology) for mounting shank screws and tools for turning them (such as hex keys). The intermediary portion may then have a lower sub-section which is not cylindrical and extends to the end cutting portion. It will be understood that the shank portion includes abutment regions for the shank screws and abutment regions for contacting an adaptor, and the intermediary portion is essentially defined as connecting the shank portion and end cutting portion but having no clamping or cutting function in itself (except for possible embodiments where cutting pockets are added, in accordance with some aspects where this has not been explicitly excluded).

[0041] It will be understood that the cutting tool of the present aspect may advantageously have the features of or be produced in accordance with the previous aspects but is not limited thereto and may be produced in accordance with other methods for the independent advantages below.

[0042] In order to further reduce weight, instead of a large flange attachment (for a standard flange adaptor) a new attachment configuration was conceived as defined above. By reducing the size of the flange which typically has bores through which screws are inserted, material was deemed removable from the side of the bores leaving slots. This further allowed the flange to be of a smaller diameter as the screws can be inserted sideways and do not need an axial length (which would impede the intermediary portion shown) for insertion.

[0043] In accordance with an eighth aspect of the subject matter of the present application, there is provided a cartridge comprising: a cartridge top surface; a cartridge bottom surface opposite the cartridge top surface; a cartridge first side surface extending between the cartridge top surface and the cartridge bottom surface; a cartridge second side surface opposite the cartridge first side surface; a cartridge front end surface extending between the cartridge top surface, the cartridge bottom surface, the cartridge first side surface and the cartridge second side surface; a cartridge rear end surface opposite the cartridge front end surface; and a cutting insert pocket formed at the cartridge top surface, and opening out to at least one of the cartridge first side surface and the cartridge front end surface; an anchoring bore opening out to at least one of the cartridge second side surface and the cartridge bottom surface and being oriented towards both of the cartridge top surface and the cartridge first side surface; wherein: the anchoring bore is threaded.

[0044] During production of a reduced-weight cutting tool, it was conceived that a compact cartridge allowing fine-tuning adjustment of a cutting insert would be beneficial. While cartridges are known for fine-tuning, reducing a cartridge size allows reduction of size and hence weight of a tool configured for holding such compact cartridge.

[0045] It was found, inter alia, that by reversing the traditional direction of a clamping screw used to hold a cartridge to a tool via a screw head thereof, and only using a screw shank to pull the cartridge into a secured position, less area was needed on the cartridge surface allowing a shortened cartridge to be provided.

[0046] Preferably, the anchoring bore is further oriented towards the cartridge front end surface. This allows a screw fastened to the anchoring bore to pre -bias the cartridge against an adjustmentbore abutment surface (in the exemplified embodiment via a set screw) to ensure contact at all times.

[0047] Preferably, the anchoring bore is a blind hole. Accordingly, the cartridge can be shorter as the anchoring bore may still allow a portion of an insert pocket to be located thereabove.

[0048] Preferably, the cartridge further comprises an adjustment bore opening out to the rear end surface; wherein the adjustment bore is threaded. While the fine-tuning adjustment could be carried out merely by biasing the cartridge on a surface thereof, the use of a threaded adjustment bore allows a single screw in contact therewith to move the cartridge in two opposite directions and not just provide abutment in one direction.

[0049] Preferably, all of the bores of the cartridge are threaded. Accordingly, no threading is needed at the cutting pockets of the associated cutting tool and preferably no threading is needed for the entire associated cutting tool.

[0050] The cartridge can be defined as follows: the cartridge is elongated along a longitudinal axis AL extending through the cartridge front end surface and the cartridge rear end surface; a cartridge length CL is defined parallel to the longitudinal axis AL and from the cartridge front end surface to the cartridge rear end surface; a cartridge width CW is defined perpendicular to the longitudinal axis AL and from the cartridge first side surface to the cartridge second side surface; a cartridge height CH is defined perpendicular to the longitudinal axis AL and from the cartridge bottom surface to the cartridge top surface; an insert pocket length PL is defined parallel to the cartridge length CL; an insert pocket width PW is defined parallel to the cartridge width CW; and an insert pocket height PH is defined parallel to the cartridge height CH.

[0051] Preferred compact dimensions of a cartridge are as follows: preferably, the cartridge length CL fulfills the condition: CL < 3CW, preferably CL < 2CW and most preferably CL < 1.5CW; preferably, the cartridge length CL fulfills the condition: CL < 3PL, preferably CL < 2PL and most preferably CL < 1.5PL; and preferably, the cartridge width CW fulfills the condition: CW < 3PW, preferably CW < 2PW and most preferably CW < 1.5PW.

[0052] It will be understood that the cartridge of the present aspect may be advantageous with a cutting tool of any of the previous aspects.

[0053] Similarly, any of the cutting tools according to any of the aspects can preferably have an intermediary portion with an upwardly-directed build construction. Any of the cutting tools according to any of the aspects can preferably have a perforated intermediary portion. Any of thecutting tools according to any of the aspects can preferably have the dimensions or shape defined in the various aspects.

[0054] The following general points, detailing more precise advantageous features, relate to each of the above aspects separately or in combination.

[0055] Generally speaking, "cutting pockets" when mentioned in all of the aspects above can be for removable inserts (commonly called "cutting inserts"), brazed cutting elements or cartridges which themselves are configured with insert pockets designed to hold cutting inserts, which may be removable or brazed. While the most preferred option for the types of tools under discussion are removable inserts mounted to cartridges which are in turn mounted to cutting tool pockets, it will be understood that the many advantageous aspects above could also be used with brazed cutting elements or cutting inserts directly mounted to the cutting tools.

[0056] An upwardly-directed build construction preferably has a minimum upward-build angle 0 which fulfils the condition: 0 > 25°, more preferably 0 > 35° and most preferably 0 45°. It will be understood that some printing machines can produce acceptable quality even at angles below 45°, in particular for short distances, however for large distances and best quality angles the above values are preferred.

[0057] The intermediary portion preferably fulfills the condition: LI > LE, preferably LI > 2LE, more preferably LI > 3LE and most preferably LI > 4LE. It will be understood that an increased length (when needed for a machining application) can result in greater weight reduction compared to known cutting tools.

[0058] The intermediary portion preferably fulfills the condition: LI > LS, preferably LI > 2LS, and most preferably LI > 3LS. It will be understood that an increased length (when needed for a machining application) can result in greater weight reduction compared to known cutting tools.

[0059] The cutting tool preferably fulfills the condition: CS < CE, preferably CS < 0.95CE, more preferably CS < 0.90CE and most preferably CS < 0.8CE. It will be understood that a cutting tool built with a shank distal from a build surface can be more easily machined if there is more free area therearound. While such production as outlined in the first aspect can actually disadvantageously reduce the number of items that can be printed on a build surface, since said area is needed for machining before separation from the build surface, it was found for cutting tools which have larger end cutting portions than their shank portions there is no such disadvantage. It will be understood that even cutting tools without this advantageous shape couldstill be produced in accordance with the first aspect but would likely require a producer to reduce the number of items on the build surface.

[0060] Preferably, the intermediary minimum circumscribed diameter CI2 is closer than the intermediary maximum circumscribed diameter CI1 to the shank portion, and the intermediary minimum circumscribed diameter CI2 fulfills the condition: CI2 < CS; preferably CI2 < 0.95CS, more preferably CI2 < 0.90CS and most preferably CI2 < 0.8CS. It will be understood that said hourglass shape design is more beneficial when there is a significant enlargement of the diameter further from the shank portion.

[0061] Preferably, the intermediary minimum circumscribed diameter CI2 is closer than the intermediary maximum circumscribed diameter CI1 to the shank portion, and the intermediary minimum circumscribed diameter CI2 fulfills the condition: CI2 < CI1; preferably CI2 < 0.95CI1, more preferably CI2 < 0.90CI1 and most preferably CI2 < 0.8CI1. It will be understood that such construction allows more area for subtractive machining of the shank portion. Additionally, it is preferred that the intermediary minimum circumscribed diameter CI2 gradually increases in size to the maximum circumscribed diameter CI1. It will be understood that this allows high-quality printing without the need for additional supports that need to be subsequently removed.

[0062] It will be understood that the present invention is particularly advantageous for milling tools due to their shape (which typically allows more area for machining around a shank portion), especially when the diameter of the tool is larger at areas distal from the shank portion. For this reason each of the following features are separately and in combination advantageous: a. Preferably, in a forward axial view, the end cutting portion has a basic circular shape. b. Preferably, the at least one cutting pocket of the end cutting portion is a plurality of cutting pockets circumferentially spaced about the axis A, the axis A further defining a circumferentially extending cutting direction DC thereabout, and a circumferentially extending anti-cutting direction DA opposite to the cutting direction DC. Additionally, it is preferable that the cutting pockets are of a number N fulfilling the condition: N > 4, preferably N > 6 and most preferably N > 7. Notably, with more cutting pockets (which require a suitably sized flute for chip evacuation therebetween) there is typically a larger diameter end cutting portion. c. Preferably, in a rearward axial view, the shank portion has a basic circular shape.

[0063] It will be understood that the intermediary portion allows for minimized post-machining (i.e. removal of supports). Thus, preferably, at least structural strength components of the intermediary portion have an external surface with an additive-texture. By “additive-texture” it is meant that the external surface as a visible texture identifiable as having been produced by printing (e.g. a layered construction) as opposed to a visible texture which was post-machined after the printing with a chip-removal subtractive process such as milling, drilling or turning (notably polishing, sand-blasting, tumbling and similar light post-machining processes are not chip-removal processes). Alternatively, “subtractive-texture” means that a chip-removal process was carried out on a specified surface. By structural strength components it means structures which connect the shank portion and end cutting portion (or stated differently, this excludes cutting pockets which may be formed on the intermediary portion according to some aspects). Additionally, preferably the entire external surface of the intermediary portion has an additive-texture. In such case the entire intermediary portion is free of support removal. Stated differently it is preferred that the entire intermediary portion has an additive-texture.

[0064] It will be understood that the following features are preferred to reduce the amount of post-machining of a cutting tool: preferably at least one cutting pocket has an external surface with an additive-texture; preferably, each at least one cutting pocket has an external surface with a subtractive-texture; preferably, at least one radially-outward directed external surface of the shank portion has an additive-texture has an additive-texture; preferably, the only external surfaces areas of the cutting tool having a subtractive-texture outer surface are the shank portion and the end cutting portion; preferably, the only external surfaces of the end cutting portion having a subtractive-texture is the at least one cutting pocket.

[0065] In embodiments where the intermediary portion is perforated, advantageous features allowing improved reduction of weight while not overly sacrificing structural strength have been found as follows: a. Preferably, a first perforation of the perforations is closest to the end cutting portion and has a first perforation width WP1, and a second perforation of the perforations which is closer to the shank cutting portion than the first perforation, has a second perforation width WP2, the first perforation width WP1 fulfills the condition: WP1 > WP2, preferably WP1 > 1.5WP2, more preferably WP1 > 2WP2 and most preferably WP1 > 3WP2. It will be understood that tools gripped at a shank portion and which machine at a distal end thereof undergo more bendingforces closer to the shank portion. Accordingly, it has been found advantageous for larger perforations to be made further from the bending forces, i.e. closer to the end cutting portion. b. Preferably, a first perforation of the perforations narrows in the upward direction DU, and has a first perforation width WP1 which is the maximum width thereof; the first perforation further extending below the maximum width thereof to one side in the downward direction DD. It has been long known that so-called tear-drop or pear shaped perforations are advantageous for printing. It has been found that due to cutting forces on the cutting tool, the above-described asymmetric shape is preferred. c. Similarly, elongated perforations and more preferably those extending at an acute angle to the upward direction (or axis A) are also believed to be better suited for cutting forces. Thus it is preferable when at least one of said perforations is elongated along a perforation elongation direction DP defined individually per perforation, and said perforation has a perforation width WP defined perpendicular to the perforation elongation direction DP of that individual perforation. More preferable are perforations wherein the elongation direction forms an acute angle £ with the axis A in the upward direction. Preferably, an acute angle £ fulfills the condition: 90° > £ > 45°, preferably 90° > £ > 60° and most preferably 90° > £ > 75°. It may further be preferred that the acute angle £ fulfills the condition: 88° > £ > 45°, more preferably 88° > £ > 60° and most preferably 85° > £ > 75°. Typically, due to the common cutting direction of a rotating tool being in the counter-clockwise direction in a forward axial view as shown in Fig. 9C, it is preferred that the perforations extend in the clockwise direction (in a side view of the cutting tool) with increasing proximity to the end cutting portion. d. Preferably, at a first cross-section perpendicular to the axis A at the intermediary portion of the cutting tool has a first void to material ratio V 1 :M1 , and at a second cross-section perpendicular to the axis A at the intermediary portion closer to the end cutting portion than the first crosssection, the cutting tool has a second void to material ratio V2:M2; the second void to material ratio V2:M2 fulfilling the condition: V2:M2 > V1 :M1. This configuration is preferred due to the bending forces being greater proximate to the shank portion as explained above. Stated differently, because the bending forces are lesser near the end cutting portion, there can be less material, relative to a position further from the end cutting portion. While the present discussion is about achieving such ratio with perforations, it will be understood that altering the thickness of a cutting tool’s material or increasing or decreasing a lattice density cansimilarly achieve a desired reduction of weight. Nonetheless, perforations are believed to be the most advantageous structure since the thicker rod-like construction better supports cutting forces which may otherwise buckle a thinner construction. e. It will be understood that larger perforations, perforation widths or void ratios may be more conveniently produced wherein, preferably, a second diameter D2 of the second cross-section is larger than a first diameter D 1 of the first cross-section (the second diameter D2 being at the intermediary portion closer to the end cutting portion than the first diameter D 1 , which is also at the intermediary portion). This may be producible without supports requiring removal when, preferably, a diameter of the cutting tool increases continuously from the first cross-section to the second cross-section (accordingly this feature of continuous or smooth diameter increase, is preferable for all embodiments even those without perforations). Similarly, it is preferred when a void to material ratio V:M increases continuously from the first cross-section to the second cross-section. f. For the reasons mentioned above relating to bending and / or increasing diameter, it is preferred when the perforations follow a pattern of increasing in size with increasing proximity to the end cutting portion.

[0066] Preferably, coolant passageways can extend internally through the cutting tool and particularly through the intermediary portion.

[0067] Preferably the shank portion can be formed with shank voids to further reduce weight.

[0068] Preferably, all cutting pockets of the cutting tool are formed with threadless bores. Even more preferably, the cutting tool is devoid of threaded bores. It will be understood that this reduces post-machining production of threads.

[0069] In embodiments having a cavity and a cavity top surface and any one, or any combination thereof, of the following may be included: a. Preferably, the cavity top surface has a conical shape. b. Preferably, the cavity top surface has a cavity apex which lies on the axis A. c. Preferably, the central cavity extends into the shank portion. d. Preferably, the shank portion has a shank cavity opening out in the upward direction DU and having a cavity bottom surface which tapers in the upward direction DU. e. Preferably, the shank cavity is in fluid connection with coolant passageways extending to the end cutting portion.f. Preferably, a minimum upward-build angle 0 of the cavity top surface which fulfils the condition: 0 > 25°, preferably 0 > 35° and most preferably 0 45°.

[0070] To assist locating the cutting pockets to be post-machined after separation of the cutting tool from a build surface, it is preferred that a shank portion has a flat surface or straight groove indicator surface formed on the exterior surface thereof.BRIEF DESCRIPTION OF THE DRAWINGS

[0071] For a better understanding of the subject matter of the present application, and to show how the same may be carried out in practice, reference will now be made to the accompanying drawings, in which:Fig. 1 is a side view of a cutting tool assembly connected to an adaptor, the cutting tool assembly comprising a cutting tool, screws, cartridges and cutting inserts;Fig. 2A is a perspective view of the cutting tool in Fig. 1;Fig. 2B is another perspective view of the cutting tool in Fig. 1;Fig. 2C is a side view of the cutting tool in Fig. 1 ;Fig. 2D is another side view of the cutting tool in Fig. 1, rotated 90° from Fig. 2C;Fig. 2E is a rearward axial view of the cutting tool in Fig. 1, stated differently,Fig. 2E is a top view of the cutting tool;Fig. 2F is a forward axial view of the cutting tool in Fig. 1 ;Fig. 3 is a sectional view taken along line III-III in Fig. 2D;Fig. 4 is a partial view of an intermediary portion of the cutting tool in claim 1 , the view being directed towards a perforation of the intermediary portion, stated differently, the view is an axial view of the perforation;Fig. 5 is a schematic view of a cartridge, cutting insert and screws of the cutting tool assembly in Fig. 1, together with tools (hex keys) showing operation and an adjustment direction of the cartridge;Fig. 6 is an exploded view of the cartridge and screws in Fig. 5, with the cutting insert still mounted to the cartridge;Fig. 7A is a front view of the cartridge in Fig. 5;Fig. 7B is a first side view of the cartridge in Fig. 5;Fig. 7C is a top view of the cartridge in Fig. 5;Fig. 7D is a second side view of the cartridge in Fig. 5;Fig. 7E is a rear view of the cartridge in Fig. 5 ;Fig. 7F is a perspective lower-side view of the cartridge in Fig. 5;Fig. 8A is a partial perspective view of a pocket of the cutting tool in Fig. 1 ;Fig. 8B is a schematic front view of a pocket in Fig. 8 A, with hidden features in dashed lines;Fig. 8C is a schematic side view of a pocket in Fig. 8A, with hidden features in dashed lines;Fig. 9A is a rearward axial view of the cutting tool in Fig. 1 ;Fig. 9B is a side view of the cutting tool in Fig. 1 and a schematically shown build surface; and Fig. 9C is a forward axial view of the cutting tool in Fig. 1.DETAILED DESCRIPTION

[0072] Reference is made to Fig. 1 which illustrates a cutting tool assembly 10 connected to an adaptor 12.

[0073] Referring also to Figs. 5 and 6, the cutting tool assembly 10 comprising an additive- manufactured cutting tool 14 (which in this non-limiting embodiment is a face-mill), a plurality of shank screws 16 fastening the cutting tool 14 to the adaptor 12, a plurality of cartridges 18, a plurality of cartridge screws 20 for securing the cartridges 18 to the cutting tool 14, a plurality of adjustment screws 22 for fine tuning the cartridges 18, and a plurality of cutting inserts 24 removably secured to the cartridges 18 via insert screws 26, and an adjustment direction DJ.

[0074] Referring to Figs. 9A to 9C, the cutting tool 14 will be described in detail. The cutting tool 14 comprises: a shank portion 28 having an axis A extending through the center thereof; an end cutting portion 30; and an intermediary portion 32.

[0075] While the shank portion 28 defines the orientation and position of axis A, it will be understood that the axis A extends through the entire cutting tool 14.

[0076] The axis A further defines: an upward direction DU; a downward direction DD; a radially- outward direction DO; a radially-inward direction DI, a circumferentially extending cutting direction DC and a circumferentially extending anti-cutting direction DA.

[0077] As explained, production of the cutting tool 14 starts on a build surface 34. The printing can be the type called Powder Bed Fusion and it proceeds in the defined upward direction DU and the end cutting portion 30 is first produced on the build surface 34. Notably, cutting pockets 40shown in the figures have undergone subtractive manufacturing as can be seen by downwardly oriented (or, stated differently, downwardly facing, i.e. facing in the downward direction) pocket rear surfaces 36. It will be understood that the additive production steps are being described for the purposes of understanding, nonetheless a finished product is shown in the figures.

[0078] It will be understood that the downwardly oriented pocket rear surfaces extend a significant length and therefore are not printed in the orientation shown. It will be understood that if the cutting tool would have been oriented oppositely, i.e. with the end cutting portion 30 distal from the build surface 34 instead of adjacent thereto, the cutting pockets 40, and more specifically the pocket rear surfaces 36 thereof, could have been produced by printing with, at most, only a light finishing operation to bring it to high precision.

[0079] Nonetheless, it can be seen by looking at the figures and particularly Fig. 3, that all of the surfaces of the intermediary portion 32 extend in at least a short horizontal if not significantly upward build direction allowing for clean printing production free of supports (not shown) requiring subsequent removal.

[0080] Reverting to Figs. 9A to 9C, the end cutting portion 30 exemplified, comprises nine cutting bulges 38 (which after additive manufacture have cutting pockets 40 formed thereon by a subtractive machining process, as shown already in the figures), each pair of adjacent cutting bulges 38 being separated by a chip evacuation flute 42, and the end cutting portion 30 has a cutting length LE parallel to the axis A (and extending from the build surface 34 to a top height of the cutting bulges 38) and an end circumscribed diameter CE.

[0081] The printing continues in the upward direction DU, producing the intermediary portion 32 on (i.e. above) the end cutting portion 30.

[0082] The intermediary portion 32 starts at a first position 44 corresponding to a top height of the cutting bulges 38 and extends to a second position 46 corresponding to a lowest height of the shank portion 28, which defines an intermediary length LI.

[0083] In this embodiment, the intermediary portion 32 comprises a lower sub-section 48, a cylindrical sub-section 50 and a transition sub-section 52.

[0084] The lower sub-section 48 extends from the first position 44 to a third position 54, in a smooth or continuous inward and upward direction except for a small inward radius corner 56 where it transitions to the cylindrical sub-section 50. The lower sub-section 48 has a lower subsection length LQ.

[0085] The cylindrical sub-section 50 extends from the third position 54 to a fourth position 58, with a constant external diameter (corresponding to the intermediary minimum circumscribed diameter CI2). The cylindrical sub-section 50 has a cylindrical sub-section length LC.

[0086] The transition sub-section 52 extends from the fourth position 58 to the second position 46, in a smooth or continuous radially-outward and upward direction DO, DU. The transition subsection 52 has a transition sub-section length LR and a transition width schematically indicated as "WR" (which varies from the cylindrical sub-section's external diameter to a shank circumscribed diameter CS; in essence the transition width is the cylindrical sub-section's external diameter CI2 plus twice the drawn WR dimension amount at a given axial position). The transition sub-section 52 is further formed with slot extensions 60.

[0087] The printing subsequently continues in the upward direction DU produce the shank portion 28 on (i.e. above) the intermediary portion 32.

[0088] The shank portion 28 has an axis A extending through the center thereof, a shank circumscribed diameter CS, and a shank length LS. The shank portion 28 is further formed with a flat indicator surface 62 located along an otherwise cylindrical shank outer surface 64, a standard arbor slot 66 formed at a shank top abutment surface 68 and, by contrast to the standard feature of an arbor slot 66, the shank portion 28 comprises unique fastener slots 70. The fastener slots 70 comprise neck portions 72 and downwardly facing neck abutment surfaces 74. As shown in Fig. 9A the fastener slots 70 open out in the outward direction DO.

[0089] Notably, the slot extensions 60 of the transition sub-section are beneficial but not essential continuations of the fastener slots 70 for providing relief for the shank screws 16 (Fig. 1). Similarly, the outer diameter of the cylindrical sub-section 50 is configured to be sufficiently small so as to be relieved to allow the shank screws 16 or tools (not shown) for turning them access.

[0090] After the shank portion 28 is produced a subtractive manufacturing process is carried out on the shank portion 28 prior to detachment of the cutting tool 14 from the build surface 34. More precisely, the areas requiring precision surfaces (and therefore are subtractively machined, although this may not be required if printing technology precision improves in future) are the neck abutment surfaces 74, the shank top abutment surface 68 and the arbor slot 66. According to some embodiments the cylindrical shank outer surface 64 excluding the flat indicator surface 62 can also be machined.

[0091] Subsequently the cutting tool 14 is separated from the build surface 34 and, reverting also to Fig. 1, clamped to the adaptor 12 with the shank screws 16 abutting the neck abutment surfaces 74 and being held to threaded bores (not shown) of the adaptor 12, with the shank top abutment surface 68 in abutment with the adaptor 12.

[0092] The adaptor 12 is then held by a machine (not shown) and the indicator surface's position is detected allowing the machine to know the position of the intended cutting pockets 40.

[0093] The cutting pockets 40 are then machined in a subtractive manufacturing process.

[0094] It will be understood that other typical processes may also be carried out before or after the subtractive manufacturing process, as appropriate, such as heat treatment, sand-blasting, coating, etc.

[0095] Notably, the cutting tool 14 has a tool length LT parallel to the axis A and extending from the build surface 34 to the shank top abutment surface 68.

[0096] Regarding the varying diameters of the cutting tool 14 which show an hourglass shape: the shank portion 28 has said shank circumscribed diameter CS ; downward of the shank portion 28 the transition sub-section 52 smoothly or continuously reduces in diameter from the shank circumscribed diameter CS at the second position 46 to a first diameter D 1 of a cross section at the fourth position 58 (corresponding in size to an intermediary minimum circumscribed diameter CI2, since it is the smallest diameter of the intermediary portion 32) which is smaller than the shank circumscribed diameter CS. From the fourth position 58 to the third position 54 the cylindrical sub-section 50 has said intermediary minimum circumscribed diameter CI2 which is basically constant. Notably, the so-called hourglass shape does not require the existence of a constant diameter cylindrical sub-section as shown in this non-limiting embodiment. From the third position 54 to the first position 44 the lower sub-section 48 smoothly or continuously increases in diameter to a second diameter D2 (corresponding in size to an intermediary maximum circumscribed diameter CI1 (called such because it is the largest diameter of the intermediary portion 32).

[0097] Notably, the drawings show the dimensions designated "CI1" and "CI2" with internal arrows for convenience only, it will be understood from the term "circumscribing" that these dimensions are external diameters.

[0098] Notably the intermediary portion 32 is perforated, in this example with a first row of perforations 76 closest to the end cutting portion and a second row of perforations 78.

[0099] Referring also to Fig. 2D and Fig. 4, individual perforations (hereinafter "first perforations") in the first row of perforations 76 are designated 80, and individual perforations (hereinafter "second perforations") in the second row of perforations 78 are designated 82.

[0100] The first row of perforations 76 has a first layer length LP1 (Fig. 9B) which is larger than a second layer length LP2 of the second row of perforations 78. In this preferred embodiment, the first layer length LP1 is significantly greater than the second layer length LP2. Stated differently, in height measurements parallel to the axis A, the first perforations 80 have a first perforation height HP1 significantly greater than a second perforation height HP2 of the second perforations 82.

[0101] The first perforations 80 have a first perforation width WP1 and the second perforations have a second perforation width WP2 significantly smaller than the first perforation width WP1.

[0102] Referring to Fig. 4, the first perforation 80 has a basic pear shape completed with a dashed line 83. More precisely, the first perforation 80 narrows to a perforation apex 84 in the upward direction DU and has a first perforation width WP1 which is the maximum width thereof. The first perforation 80 further extends below the maximum width thereof at a first perforation side 86 in the downward direction. Stated differently, the first perforation side 86 extends lower than a second perforation side 87. In yet other words, about a central plane PC, the first perforation side 86 and the second perforation side 87 are asymmetric.

[0103] It should be noted that the view in Fig. 4 is directly toward the first perforation 80 at which area the intermediary portion 32 is upwardly and inwardly inclined, and therefore the upward and downward directions DU, DD shown are slightly inclined relative to the axis A, in difference to the other drawings. Thus, said directions in this figure schematically provided for understanding.

[0104] Reverting to Fig. 2D, the second perforations 82 are elongated along an elongation axis AE and form an acute angle with the axis A.

[0105] Drawing attention to Fig. 3, it will be understood that a first cross-section 90 perpendicular to the axis A and extending through the second row of perforations 78 has a first void to material ratio VI :M1 , and a second cross-section 88 perpendicular to the axis A, and closer to the end cutting portion 30 than the first cross-section 90, extends through the first row of perforations 76 and has a second void to material ratio V2:M2, and V2:M2 > V1:M1.

[0106] Referring to Figs. 2A and 3, the cutting tool 14 has a central cavity 92 extending parallel with the axis A from at least the intermediary portion 32 in the downward direction DD and opening out from the end cutting portion 30 in the downward direction DD.

[0107] The central cavity 92 comprises a conical cavity top surface 94 which tapers in the upward direction DU to a cavity apex 96.

[0108] The minimum upward-build angle 0 of the cavity top surface 94 fulfils the condition 0 45°. Notably the reference horizontal plane 98 with which the upward-build angle 0, and all other such angles of the cutting tool 14, is measured perpendicular to the axis A.

[0109] The shank portion 28 is formed with shank voids 100. The shank voids 100 open out to the outside of the cutting tool 14 via evacuation holes 102 to allow powder to exit, as is known in the art.

[0110] The shank portion 28 comprises a shank cavity 104 opening out in the upward direction DU and having a cavity bottom surface 106 which tapers in the upward direction DU. More precisely, the cavity bottom surface 106 has a conical shape.

[0111] It has been found that this tapering or conical shape provides an efficient reservoir for coolant (not shown) which is then smoothly diverted via the cavity bottom surface 106 to a plurality of coolant passageways 108 extending to the end cutting portion.

[0112] For the sake of completeness in Fig. 2C, a small portion of additive texture is schematically shown and indicated as 110 merely to fulfill drawing requirements in some jurisdictions. It will be understood that a skilled person can visually identify an external surface of a cutting tool 14 which has not undergone a chip-removal process after printing.

[0113] Referring to Figs. 5 to 8C, one of the cartridges 18 and one of the cutting pockets 40 will be further detailed.

[0114] The cartridge 18 is elongated along a longitudinal axis AL and comprises a cartridge top surface 112; a cartridge bottom surface 114; a cartridge first side surface 116; a cartridge second side surface 118; a cartridge front end surface 120; a cartridge rear end surface 122; and a cutting insert pocket 124; a cartridge length CL; a cartridge width CW; a cartridge height CH; an insert pocket length PL; an insert pocket width PW; and an insert pocket height PH.

[0115] In the present exemplary embodiment, the dimensions are: CL = 21.4mm; CW = 15.6mm; CH = 11.5mm; PL = 16.0mm; PW = 10.6mm; PH = 4.5mm; and PO = 6mm.

[0116] The cartridge is further formed with a threaded, blind hole, anchoring bore 126, a threaded adjustment bore 128 and a threaded insert bore 130.

[0117] The cutting insert pocket 124 comprises an insert pocket base surface 132 to which the threaded insert bore 130 opens out, an insert pocket rear surface 134 and an insert pocket side abutment surface 136. It should be understood that any known cutting insert pocket may be used with the cartridge according to the present invention.

[0118] The cartridge screws 20 each have a cartridge screw head 138 and a cartridge threaded shank 140.

[0119] The adjustment screws 22 are of a so-called headless set-screw type and comprise an adjustment head end 142 and an adjustment threaded shank 144.

[0120] The cutting pocket 40 comprises said pocket rear surface 36, a pocket side abutment surface 146, a pocket base surface 148, an elongated pocket anchoring bore 150, and a pocket adjustment bore 152.

[0121] The pocket anchoring bore 150 opens out to a pocket anchoring abutment surface 154.

[0122] The pocket adjustment bore 152 extends into the pocket rear surface 36 to an adjustment bore abutment surface 156 which encircles an adjustment actuator bore 158.

[0123] In operation: the cartridge screw 20 extends through the pocket anchoring bore 150 and is threadedly connected to the anchoring bore 126. The cartridge screw 20 is rotated until the cartridge screw head 138 abuts the pocket anchoring abutment surface 154 pulling the cartridge 18 into abutment with the pocket side abutment surface 146, pocket base surface 148, and the adjustment bore abutment surface 156 (via the adjustment screw 22 which will be explained below). As the pocket anchoring bore 150 is elongated it allows for a small amount of sliding movement along the pocket side abutment surface 146. Additionally, the adjustment screw 22 is threadedly connected to the threaded adjustment bore 128 and extends partially inside the pocket adjustment bore 152. The adjustment screw 22 is accessed with a hex key (Fig. 5) via the adjustment actuator bore 158 and is in contact with the adjustment bore abutment surface 156 due to the above-mentioned biasing by the cartridge screw 20. When the adjustment screw 22 is rotated it slightly adjusts the position of the cartridge with said sliding movement along the pocket side abutment surface 146.

Claims

CLAIMS1. An additive-manufactured cutting tool comprising: a shank portion having an axis A extending through the center thereof, a shank circumscribed diameter CS, and a shank length LS parallel to the axis; an end cutting portion in turn comprising at least one cutting pocket, the end cutting portion having a cutting length LE parallel to the axis and an end circumscribed diameter CE; and an intermediary portion connecting the shank portion and the end cutting portion, and has an intermediary length LI parallel to the axis, an intermediary minimum circumscribed diameter CI2 and an intermediary maximum circumscribed diameter CI1; the axis A defining: an upward direction DU directed from the end cutting portion towards the shank portion; a downward direction DD opposite to the upward direction; a radially-outward direction DO directed away from the axis; and a radially-inward direction DI opposite to the radially-outward direction; the cutting tool has a tool length LT parallel to the axis A; the shank portion, end cutting portion and intermediary portion having a unitary monolithic construction; wherein the intermediary portion has an upwardly-directed build construction.

2. The cutting tool as claimed in the preceding claim, wherein the upwardly-directed build construction has a minimum upward-build angle 0 which fulfils the condition: 0 > 25°, preferably 0 > 35° and most preferably 0 45°.

3. The cutting tool as claimed in any one of the preceding claims, fulfilling the condition: LI >LE, preferably LI > 2LE, more preferably LI > 3LE and most preferably LI > 4LE.

4. The cutting tool as claimed in any one of the preceding claims, fulfilling the condition: LI >LS, preferably LI > 2LS, and most preferably LI > 3LS.

5. The cutting tool as claimed in any one of the preceding claims, fulfilling the condition: CS < CE, preferably CS < 0.95CE, more preferably CS < 0.90CE and most preferably CS < 0.8CE.

6. The cutting tool as claimed in any one of the preceding claims, wherein the intermediary minimum circumscribed diameter CI2 is closer than the intermediary maximum circumscribed diameter CI1 to the shank portion, and the intermediary minimum circumscribed diameter CI2fulfills the condition: CI2 < CS; preferably CI2 < 0.95CS, more preferably CI2 < 0.90CS and most preferably CI2 < 0.8CS.

7. The cutting tool as claimed in any one of the preceding claims, wherein the intermediary minimum circumscribed diameter CI2 is closer than the intermediary maximum circumscribed diameter CI1 to the shank portion, and the intermediary minimum circumscribed diameter CI2 fulfills the condition: CI2 < CI1; preferably CI2 < 0.95CI1, more preferably CI2 < 0.90CI1 and most preferably CI2 < 0.8CI1.

8. The cutting tool as claimed in the preceding claim, wherein the intermediary minimum circumscribed diameter CI2 gradually increases in size to the maximum circumscribed diameter CI1.

9. The cutting tool as claimed in any one of the preceding claims, wherein, in a forward axial view, the end cutting portion has a basic circular shape.

10. The cutting tool as claimed in any one of the preceding claims, wherein the at least one cutting pocket of the end cutting portion is a plurality of cutting pockets circumferentially spaced about the axis, the axis A further defining a circumferentially extending cutting direction DC thereabout, and a circumferentially extending anti-cutting direction DA opposite to the cutting direction DC.

11. The cutting tool as claimed in the preceding claim, wherein the cutting pockets are of a number N fulfilling the condition: N > 4, preferably N > 6 and most preferably N > 7.

12. The cutting tool as claimed in any one of the preceding claims, wherein, in a rearward axial view, the shank portion has a basic circular shape.

13. The cutting tool as claimed in any one of the preceding claims, wherein at least structural strength components of the intermediary portion have an external surface with an additive - texture.

14. The cutting tool as claimed in any one of the preceding claims, wherein the entire external surface of the intermediary portion has an additive-texture.

15. The cutting tool as claimed in any one of the preceding claims, wherein the at least one cutting pocket has an external surface with an additive-texture.

16. The cutting tool as claimed in any one of the preceding claims, wherein at least one radially- outward directed external surface of the shank portion has an additive-texture.

17. The cutting tool as claimed in any one of the preceding claims, wherein the only external surfaces areas of the cutting tool having a subtractive-texture outer surface are the shank portion and the end cutting portion.

18. The cutting tool as claimed in the preceding claim, wherein the only external surfaces of the end cutting portion having a subtractive-texture is the at least one cutting pocket.

19. A method of producing an additive manufactured cutting tool comprising the steps: a) using an upwardly-directed build construction additive manufacturing process to produce an end cutting portion on a build surface; b) continuing the additive manufacturing process to produce an intermediary portion on the end cutting portion; c) continuing the additive manufacturing process to produce a shank portion on the intermediary portion; and d) using a subtractive manufacturing process on the shank portion prior to detachment of the cutting tool from the build surface.

20. The method as claimed in the previous claim, wherein subsequent to step d), an additional subtractive manufacturing process is carried out on the end cutting portion only, such that subtractive manufacturing processes are only carried out on the shank portion and the end cutting portion.

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