Patent Description:
Cutting tools are conventionally used in machining operations to remove material and form desired shapes and surfaces of a given object. For example, milling is a machining process wherein material is progressively removed in the form of "chips" to form a shape or surface from a given volume of material - often referred to as a workpiece. This may be accomplished by feeding the work piece into a rotating cutting tool (or vice-versa), often in a direction that is perpendicular to the axis of rotation of the cutting tool. Various types of cutters may be employed in milling operations, but most cutting tools include a body and one or more teeth (or cutting elements - which may be brazed or mechanically attached to the body) that cut into and remove material from the workpiece as the teeth of the rotating cutter engage the workpiece.

Nearly any solid material may be machined, including metals, plastics, composites and natural materials. Some materials are more easily machined than other types of materials, and the type of material being machined may dictate, to a large extent, the process that is undertaken to machine the workpiece, including the choice of cutting tool. For example, titanium and titanium alloys, while exhibiting a number of desirable mechanical and material characteristics, are notoriously difficult to machine.

While there are numerous reasons for the difficulty in milling titanium materials, some of them not entirely understood, some reasons may include its high strength, chemical reactivity with cutter materials, and low thermal conductivity. These characteristics tend to reduce the life of the cutter. Additionally, the relatively low Young's modulus of titanium materials is believed to lead to "chatter" in the cutting tool, often resulting in a poor surface finish of a machined workpiece. Further, the "chips" that are typically formed in machining processes such as milling are not typically small broken chips but, rather, long continuous chips which can become tangled in the machinery, posing a safety hazard and making it difficult to conduct automatic machining of titanium materials.

While there have been various attempts to provide cutting tools that provide desirable characteristics for machining various materials, including normally difficult-to-machine materials such as titanium, there is a continued desire in the industry to provide improved cutting tools for machining of a variety of materials and for use in a variety of cutting processes.

Embodiments of the invention relate to cutting tools that may be used in the machining of various materials. The cutting tool of the present invention is defined in claim <NUM>.

In one embodiment, the superhard table exhibits a density of at least <NUM> volume percent of polycrystalline diamond.

In one embodiment, superhard table exhibits a density of at least <NUM> volume percent of polycrystalline diamond.

In one embodiment, the table is not bonded to a substrate.

In one embodiment, the polycrystalline diamond exhibits an average grain size of approximately <NUM> or less. Additionally, a metal-solvent catalyst may be present in at least some interstitial regions of the polycrystalline diamond in an amount greater than approximately <NUM> percent by weight. In one embodiment, the metal-solvent catalyst comprises cobalt.

In one embodiment, the polycrystalline diamond exhibits an average grain size of approximately <NUM> or greater. Additionally, a metal-solvent catalyst may be present in at least some interstitial regions of the polycrystalline diamond in an amount less than approximately <NUM> percent by weight. In one embodiment, the metal-solvent catalyst comprises cobalt.

In one embodiment, the table exhibits a thickness of at least <NUM> x <NUM>-<NUM> (<NUM> inches).

In one embodiment, the table comprises a polycrystalline diamond table having: a plurality of diamond grains exhibiting diamond-to-diamond bonding therebetween and defining a plurality of interstitial regions; a metal-solvent catalyst occupying at least a portion of the plurality of interstitial regions, wherein the plurality of diamond grains and the metal-solvent catalyst collectively exhibit a coercivity of about <NUM> Oersteds ("Oe") to about <NUM> Oe; and wherein the plurality of diamond grains and the metal-solvent catalyst collectively exhibit a specific magnetic saturation of about <NUM> Gauss·cm<NUM>/grams ("G·cm<NUM>/g") to about <NUM>·cm<NUM>/g.

In one embodiment, the body comprises aluminum.

A method as defined in claim <NUM> is provided for removing material from a workpiece. The method comprises: providing a cutting tool as described above; rotating the cutting tool about an axis; and engaging a workpiece with rotating cutting tool.

In one embodiment, engaging a workpiece includes engaging a workpiece comprising titanium.

In one embodiment, providing the cutting element comprising a superhard table includes sintering a volume of diamond particles a high-pressure, high-temperature (HPHT) to form a plurality of diamond grains exhibiting diamond-to-diamond bonding therebetween.

In one embodiment, sintering a volume of diamond particles includes infiltrating at least some interstitial spaces between the diamond grains with a metal-solvent catalyst.

In one embodiment, the method further includes forming a catalyst depleted region in the table by removing at least some of the metal-solvent catalyst from interstitial spaces.

In one embodiment, infiltrating at least some interstitial spaces between the diamond grains with a metal-solvent catalyst includes infiltrating with a cobalt material.

In one embodiment, providing the table includes providing a volume of polycrystalline diamond that exhibits an average grain size of approximately <NUM> or less and wherein a metal-solvent catalyst is present in at least some interstitial regions of the polycrystalline diamond in an amount greater than approximately <NUM> percent by weight.

In one embodiment, providing the table includes providing a volume of polycrystalline diamond that exhibits an average grain size of approximately <NUM> or greater and wherein a metal-solvent catalyst is present in at least some interstitial regions of the polycrystalline diamond in an amount less than approximately <NUM> percent by weight.

In one embodiment, providing the cutting element comprising a superhard table includes providing a table that exhibits a thickness of at least <NUM> x <NUM>-<NUM> m (<NUM> inches).

In one embodiment, providing the cutting element comprising a superhard table includes providing a polycrystalline diamond table that exhibits approximately <NUM> volume percent diamond or greater.

In accordance with another embodiment, a cutting tool comprising a body, at least one cutting element associated with the body, the at least one cutting element consisting essentially of a polycrystalline diamond table exhibiting a thickness of at least approximately <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch).

In one embodiment, the at least one cutting element is formed of a material comprising at least approximately <NUM> volume percent diamond.

In one embodiment, the diamond table is at least approximately <NUM> volume percent diamond.

Various elements, components, features or acts of one embodiment described herein may be combined with elements, components, features or acts of other embodiments without limitation.

The drawings illustrate various embodiments of the invention, wherein common reference numerals refer to similar, but not necessarily identical, elements or features in different views or embodiments shown in the drawings.

Embodiments of the disclosure relate to cutting tools that may be used in machining processes, including milling, drilling, turning as well as variations and combinations thereof. The cutting tools may be used in shaping, forming and finishing a variety of different materials, including materials that are often difficult to machine, including, for example, titanium, titanium alloys and nickel based materials.

Referring to <FIG>, an example of the operation of a vertical milling machine (VMM) <NUM> is schematically shown. The VMM <NUM> includes a spindle <NUM> having a cutting tool <NUM> removably coupled therewith in accordance with an embodiment of the present disclosure. The VMM <NUM> also includes a table <NUM> on which a workpiece <NUM> is placed. A CNC (computer numerically controlled) controller <NUM> is in communication with the spindle <NUM> and may control the action of the spindle <NUM>. While not expressly shown in <FIG>, a frame may couple several of the components together (e.g., the spindle <NUM> and the table <NUM>). The spindle <NUM> is configured to rotate the cutting tool <NUM> about an axis <NUM> and to also move the cutting tool <NUM> in the X, Y and Z directions relative to the table <NUM> and associated workpiece <NUM>.

As noted above, the controller <NUM> is in communication with the spindle <NUM> and configured to control various operations of the VMM <NUM>. For example, the controller <NUM> may be configured to control the rotational speed of the cutting tool <NUM> and also move the spindle <NUM> (and, thus, the cutting tool <NUM>) in specified directions along the X-Y-Z axes at a desired "feed rate" relative to the workpiece <NUM>. Thus, the controller <NUM> may enable the cutting tool <NUM> to remove material from the workpiece <NUM> so as to shape it and provide a desired surface finish to the workpiece <NUM> as will be appreciated by those of ordinary skill in the art.

Referring to <FIG>, an example of the operation of a horizontal milling machine (HMM) <NUM> is schematically shown. The HMM <NUM> includes a spindle <NUM> having a cutting tool <NUM> removably coupled therewith in accordance with an embodiment of the present disclosure. The HMM <NUM> also includes a table <NUM> on which a workpiece <NUM> is placed. The table <NUM> may be vertically oriented. A CNC controller <NUM> is in communication with the spindle <NUM> and controls the action of the spindle <NUM>. In one embodiment, the controller <NUM> may also be in communication with the table <NUM> and/or spindle <NUM> to displace one or both in a desired direction, respectively, as discussed below. While not expressly shown in <FIG>, a frame may couple several of the components together (e.g., the spindle <NUM> and the table <NUM>). The spindle <NUM> is configured to rotate the cutting tool <NUM> about an axis <NUM> and to also move the cutting tool <NUM> in the X, Y and Z directions relative to the table <NUM> and the associated workpiece <NUM>. Additionally, the table <NUM> may be configured to rotate about a B-axis <NUM>, which is substantially orthogonal to the rotational axis <NUM>. In one embodiment, the controller <NUM> may be configured to control the rotational speed of the cutting tool <NUM>, displace the spindle <NUM> (and, thus, the cutting tool <NUM>) in a specified direction and at a desired "feed rate" relative to the workpiece <NUM>, and also rotate the table <NUM> (and thus the workpiece <NUM>). Thus, the controller <NUM> may enable the cutting tool <NUM> to remove material from the workpiece <NUM> so as to shape it and provide a desired surface finish to the workpiece <NUM> as will be appreciated by those of ordinary skill in the art.

It is noted that the milling machines <NUM> and <NUM> described with respect to <FIG> and <FIG> are merely examples, and that a variety of other machining systems are contemplated as incorporating a cutting tool such as is described in further detail below for use in a variety of machining operations.

Referring now to <FIG> and <FIG>, a cutting tool <NUM> is shown having a tool body <NUM> and a plurality of cutting elements or inserts <NUM>. The cutting elements <NUM> may be disposed in pockets <NUM> formed in an end or region of the body <NUM>. In some embodiments, the cutting elements may be removably coupled with the tool body <NUM> such as by a fastener <NUM>. In some embodiments, the cutting elements <NUM> may be indexable relative to the tool body <NUM>. Thus, for example, as one face 160A or edge of a given cutting element <NUM> becomes worn or damaged, the cutting element <NUM> may be rotated relative to the tool body <NUM> such that a new face or edge 160B may be presented to a workpiece for the cutting and removal of material therefrom. In some embodiments, the cutting elements <NUM> may be removably coupled with the body <NUM> using clamping mechanisms. In some embodiments, the cutting elements <NUM> may be coupled with the body <NUM> by brazing or other material joining techniques.

Various materials may be used in forming the body <NUM> of the cutting tool including various metals and metal alloys. In some embodiments, the body <NUM> may be formed of an aluminum or aluminum alloy material. Other materials that may be used in forming the tool body include, without limitation, steel and steel alloys (e.g. stainless steels), nickel and nickel alloys, titanium and titanium alloys, tungsten and tungsten alloys, tungsten carbide and associated alloys, and other metals.

The cutting elements <NUM> are formed of polycrystalline diamond. For example, referring to <FIG> the cutting elements <NUM> may include a superhard, superabrasive table <NUM> defining the working surface <NUM>. In some embodiments, the cutting element <NUM> comprises a polycrystalline diamond compact ("PDC") including a polycrystalline diamond ("PCD") table to which the substrate <NUM> is bonded. In some embodiments, the interface between the table <NUM> and the substrate <NUM> may be substantially flat or planar. In other embodiments, the interface may be domed or curved. In other embodiments, the interface between the table <NUM> and the substrate <NUM> may include a plurality of raised features or recessed features (e.g., dimples, grooves, ridges, etc.).

In some embodiments, the substrate <NUM> may comprise a cobalt-cemented tungsten carbide substrate bonded to the table <NUM>. According to the invention, the table <NUM> includes a relatively "thick diamond" table which exhibits a thickness (i.e., from the working surface <NUM> to the interface between the table <NUM> and the substrate <NUM>) that is <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch) or greater, <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch) or greater or <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch) or greater.

In one embodiment, the table <NUM> exhibits a thickness between <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch) and <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch). In one embodiment, the table <NUM> exhibits a thickness between <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch) and <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch). Examples of forming relatively thick PDCs for use in bearings and in use of subterranean drilling may be found in <CIT>.

The PCD table <NUM> includes a plurality of directly bonded-together diamond grains exhibiting diamond-to-diamond bonding therebetween (e.g., sp3 bonding), which define a plurality of interstitial regions. A portion of the interstitial regions of the PCD table may include a metal-solvent catalyst or a metallic infiltrant disposed therein that is infiltrated from the substrate <NUM> or from another source during fabrication. For example, the metal-solvent catalyst or metallic infiltrant may be selected from iron, nickel, cobalt, and alloys of the foregoing. In some embodiments, the PCD table <NUM> may further include thermally-stable diamond in which the metal-solvent catalyst or metallic infiltrant has been partially or substantially completely depleted (e.g., region <NUM> shown in <FIG> and <FIG>) from a selected surface or volume of the PCD table, such as via an acid leaching process. Thermally-stable PCD may also be sintered with one or more alkali metal catalysts. In some embodiments, the catalyst-depleted region <NUM> may exhibit a depth that is substantially conformal with an outer surface of the PCD table <NUM>, such as shown in <FIG> and <FIG>. In other embodiments, the catalyst-depleted region <NUM> may generally extend a desired depth from a plane extending through the uppermost portions of the table <NUM> (e.g., through the peripheral edges of the working surface <NUM> and/or through the upper surface of the lip <NUM> - see <FIG>). Thus, removal of the catalyst or infiltrant may be done prior to or after the forming of the structures and features (e.g., chip breakers <NUM>, opening <NUM>, etc. as described hereinbelow). For example, <FIG> shows an embodiment where the removal of catalyst material does not extend substantially into the hole <NUM>. This may be because of selective catalyst removal techniques (e.g., masking), or it may be because the hole <NUM> was formed after catalyst removal.

In some embodiments, PDCs which may be used as the cutting elements <NUM> may be formed in an HPHT process. For example, diamond particles may be disposed adjacent to the substrate <NUM>, and subjected to an HPHT process to sinter the diamond particles to form the PCD table and bond the PCD table to the substrate <NUM>, thereby forming the PDC. The temperature of the HPHT process may be at least about <NUM> (e.g., about <NUM> to about <NUM>) and the cell pressure, or the pressure in the pressure-transmitting medium (e.g., a refractory metal can, graphite structure, pyrophyllite, etc.), of the HPHT process may be at least <NUM> GPa (e.g., about <NUM> GPa to about <NUM> GPa or about <NUM> GPa to about <NUM> GPa) for a time sufficient to sinter the diamond particles.

In some embodiments, the diamond particles may exhibit an average particle size of about <NUM> or less, such as about <NUM> or less, about <NUM> or less, about <NUM> to about <NUM>, about <NUM> to about <NUM>, about <NUM> to about <NUM>, or about <NUM> to about <NUM>. In some embodiments, the average particle size of the diamond particles may be about <NUM> or less, such as about <NUM> to about <NUM> or submicron. In some embodiments, the diamond particles may exhibit multiple sizes and may comprise, for example, a relatively larger size and at least one relatively smaller size. As used herein, the phrases "relatively larger" and "relatively smaller" refer to particle sizes (by any suitable method) that differ by at least a factor of two (e.g., <NUM> and <NUM>). According to various embodiments, the mass of diamond particles may include a portion exhibiting a relatively larger size (e.g., <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) and another portion exhibiting at least one relatively smaller size (e.g., <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, less than <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, less than <NUM>). For example, in one embodiment, the diamond particles may include a portion exhibiting a relatively larger size between about <NUM> and about <NUM> and another portion exhibiting a relatively smaller size between about <NUM> and <NUM>. In some embodiments, the diamond particles may comprise three or more different sizes (e.g., one relatively larger size and two or more relatively smaller sizes), without limitation. The PCD table so-formed after sintering may exhibit an average diamond grain size that is the same or similar to any of the foregoing diamond particle sizes and distributions. More details about diamond particle sizes and diamond particle size distributions that may be employed are disclosed in <CIT>.

In some embodiments, the diamond grains of the resulting table <NUM> may exhibit an average grain size that is equal to or less than approximately <NUM> and include cobalt content of greater than about <NUM> weight percent (wt. In some other embodiments, the diamond grains of the resulting table <NUM> may exhibit an average grain size that is equal to or greater than approximately <NUM> and include cobalt content of less than approximately <NUM> wt. In some embodiments, the diamond grains of the resulting table may exhibit an average grains size that is approximately <NUM> to approximately <NUM>.

In some embodiments, tables <NUM> may be formed as PCD tables at a pressure of at least about <NUM> GPa, may exhibit a coercivity of <NUM> Oe or more, a high-degree of diamond-to-diamond bonding, a specific magnetic saturation of about <NUM>·cm<NUM>/g or less, and a metal-solvent catalyst content of about <NUM> wt. The PCD may include a plurality of diamond grains directly bonded together via diamond-to-diamond bonding to define a plurality of interstitial regions. At least a portion of the interstitial regions may be occupied by a metal-solvent catalyst, such as iron, nickel, cobalt, or alloys of any of the foregoing metals. For example, the metal-solvent catalyst may be a cobalt-based material including at least <NUM> wt. % cobalt, such as a cobalt alloy.

The metal-solvent catalyst that occupies the interstitial regions may be present in the PCD in an amount of about <NUM> wt. In some embodiments, the metal-solvent catalyst may be present in the PCD in an amount of about <NUM> wt. % to about <NUM> wt. %, such as about <NUM> wt. % to about <NUM> wt. In other embodiments, the metal-solvent catalyst content may be present in the PCD in an amount less than about <NUM> wt. %, such as about <NUM> wt. % to about <NUM> wt. % or a residual amount to about <NUM> wt. By maintaining the metal-solvent catalyst content below about <NUM> wt. %, the PCD may exhibit a desirable level of thermal stability.

Generally, as the sintering pressure that is used to form the PCD increases, the coercivity may increase and the magnetic saturation may decrease. The PCD defined collectively by the bonded diamond grains and the metal-solvent catalyst may exhibit a coercivity of about <NUM> Oe or more and a metal-solvent catalyst content of less than about <NUM> wt. % as indicated by a specific magnetic saturation of about <NUM>·cm<NUM>/g or less. In a more detailed embodiment, the coercivity of the PCD may be about <NUM> Oe to about <NUM> Oe and the specific magnetic saturation of the PCD may be greater than <NUM>·cm<NUM>/g to about <NUM>·cm<NUM>/g. In an even more detailed embodiment, the coercivity of the PCD may be about <NUM> Oe to about <NUM> Oe and the specific magnetic saturation of the PCD may be about <NUM>·cm<NUM>/g to about <NUM>·cm<NUM>/g. In yet an even more detailed embodiment, the coercivity of the PCD may be about <NUM> Oe to about <NUM> Oe and the specific magnetic saturation of the PCD may be about <NUM>·cm<NUM>/g to about <NUM>·cm<NUM>/g. The specific permeability (i.e., the ratio of specific magnetic saturation to coercivity) of the PCD may be about <NUM> or less, such as about <NUM> to about <NUM>. Despite the average grain size of the bonded diamond grains being less than about <NUM>, the metal-solvent catalyst content in the PCD may be less than about <NUM> wt. % resulting in a desirable thermal stability.

In one embodiment, diamond particles having an average particle size of about <NUM> to about <NUM> are positioned adjacent to a cobalt-cemented tungsten carbide substrate and subjected to an HPHT process at a temperature of about <NUM> to about <NUM> and a cell pressure of about <NUM> GPa to about <NUM> GPa. The PCD so-formed as a PCD table bonded to the substrate may exhibit a coercivity of about <NUM> Oe to about <NUM> Oe, a specific magnetic saturation of about <NUM>·cm<NUM>/g to about <NUM>·cm<NUM>/g, and a cobalt content of about <NUM> wt. % to about <NUM> wt.

In one or more embodiments, a specific magnetic saturation constant for the metal-solvent catalyst in the PCD may be about <NUM>·cm<NUM>/g to about <NUM>·cm<NUM>/g. For example, the specific magnetic saturation constant for the metal-solvent catalyst in the PCD may be about <NUM>·cm<NUM>/g to about <NUM>·cm<NUM>/g. It is noted that the specific magnetic saturation constant for the metal-solvent catalyst in the PCD may be composition dependent.

Generally, as the sintering pressure is increased above <NUM> GPa, a wear resistance of the PCD so-formed may increase. For example, the Gratio may be at least about <NUM>. 0x10<NUM>, such as about <NUM>. 0x10<NUM> to about <NUM>. 0x10<NUM> or, more particularly, about <NUM> x10<NUM> to about <NUM> x10<NUM>. In some embodiments, the Gratio may be at least about <NUM> x10<NUM>. The Gratio is the ratio of the volume of workpiece cut (e.g., between about <NUM> in<NUM> of barre granite to about <NUM> in<NUM> of barre granite) to the volume of PCD worn away during the cutting process. It is noted that while such a process may involve a so-called "granite log test," this process is still applicable for determining the Gratio of the PCD even though the cutter may be intended for use in metal cutting processes rather than rock cutting or drilling.

The material characteristics discussed herein, as well as other characteristics that may be provided in a cutting element <NUM>, including processes for measuring and determining such characteristics, as well as methods of making such cutting elements, are described in <CIT>, <CIT>, and <CIT>.

In some embodiments, the table <NUM> may comprise high density polycrystalline diamond. For example, in some embodiments, the table <NUM> may comprise approximately <NUM> percent diamond by volume (vol. %) or greater. In some embodiments, the table <NUM> may comprise approximately <NUM> vol. % diamond or greater. In some embodiments, the table <NUM> may comprise approximately <NUM> vol. % diamond or greater. In other embodiments, the table may comprise polycrystalline diamond or relatively low diamond content. For example, in some embodiments, the table <NUM> may comprise less than <NUM> percent diamond by volume (vol.

In some embodiments, the table <NUM> may be integrally formed with the substrate <NUM> such as discussed above. In some other embodiments, the table <NUM> may be a pre-formed table that has been HPHT bonded to the substrate <NUM> in a second HPHT process after being initially formed in a first HPHT process. For example, the table <NUM> may be a pre-formed PCD table that has been leached to substantially completely remove the metal-solvent catalyst used in the manufacture thereof and subsequently HPHT bonded or brazed to the substrate <NUM> in a separate process.

The substrate <NUM> may be formed from any number of different materials, and may be integrally formed with, or otherwise bonded or connected to, the table <NUM>. Materials suitable for the substrate <NUM> may include, without limitation, cemented carbides, such as tungsten carbide, titanium carbide, chromium carbide, niobium carbide, tantalum carbide, vanadium carbide, or combinations thereof cemented with iron, nickel, cobalt, or alloys thereof.

However, in some embodiments, the substrate <NUM> may be omitted and the cutting elements <NUM> includes a polycrystalline diamond body that has been leached to deplete the metal-solvent catalyst therefrom.

As discussed above, in some embodiments, the table <NUM> is leached to deplete a metal-solvent catalyst or a metallic infiltrant therefrom in order to enhance the thermal stability of the table <NUM>. The PCD table <NUM> is leached to remove at least a portion of the metal-solvent catalyst, that was used to initially sinter the diamond grains to form a leached thermally-stable region <NUM>, from a working region thereof to a selected depth. The leached thermally-stable region may extend inwardly from the working surface <NUM> to a selected depth. In an embodiment, the depth of the thermally-stable region may be about <NUM> to about <NUM>,<NUM>. More specifically, in some embodiments, the selected depth is about <NUM> to about <NUM>, about <NUM> to about <NUM>, or about <NUM> to about <NUM>. The leaching may be performed in a suitable acid, such as aqua regia, nitric acid, hydrofluoric acid, or mixtures of the foregoing.

As depicted in <FIG>, the cutting elements <NUM> may be configured to exhibit a substantially square outer profile when viewed from above (i.e., as seen specifically in <FIG>). Such a geometry provides multiple cutting edges 160A-160D which may be indexed relative to a cutting tool body <NUM> for extended service of the cutting elements <NUM>. However, it is noted that other shapes and outer profiles are contemplated including, for example, circular, curved, triangular, hexagonal, octagonal, and other regular or irregular polygons.

As seen in <FIG>, the cutting elements <NUM> also include an opening <NUM> formed in the table <NUM> and substrate <NUM> to accommodate a fastener for coupling of the cutting element <NUM> with a cutting tool body <NUM>. The opening <NUM> may include a countersunk region <NUM> (or a counter bore, depending on the type of fastener being used) to enable a fastener to be positioned flush with or below the working surface <NUM> of the table <NUM> when the cutting element <NUM> is coupled with a cutting tool body <NUM>.

Features for breaking chips of material that are being removed from the workpiece when engaged by the rotating cutting tool <NUM> are also provided in the cutting elements <NUM>. As seen best in <FIG> and <FIG>, the cutting elements include formations or structures referred to as chip breakers <NUM>. The chip breakers <NUM> include a declining ramped surface portion <NUM> formed within the table <NUM> extending radially inward from a location adjacent the outer periphery of the table <NUM>. The chip breaker <NUM> further include a portion that is angled or curved, referred to as a return portion <NUM>, that leads up to a protruding lip <NUM> positioned adjacent to and surrounding the opening <NUM>. As material is removed from a workpiece, the removed material travels along the ramped surface portion <NUM> and then abruptly changes directions as it encounters the return portion <NUM>, promoting the breaking of the removed material into smaller "chips. " Breaking the material removed from a workpiece into smaller, discrete chips, instead of allowing the removed material to remain as long strings, helps to reduce potential interference of the removed material with the ongoing machining process.

Various methods may be employed to form the opening <NUM>, countersunk region <NUM>, chip breaker <NUM>, or other geometric features, including processes such as laser machining and laser cutting. Some non-limiting methods of forming such features in the cutting element are described in <CIT>, <CIT>Patent Application No. <CIT>, corresponding to publication number <CIT>). Additionally, the cutting elements <NUM> may be subjected to other processes to obtain desired characteristics or features. For example, at least a portion of a surface of the table <NUM> may be polished (e.g., at least a portion of a PCD surface may be polished) to a finish of approximately <NUM> x <NUM>-<NUM> m (<NUM> micro inches (µ in)) root mean square (RMS). Examples of surface finishing processes and tables with various surface finishes are described in <CIT>, corresponding to publication number <CIT>).

While the cutting elements <NUM> and the cutting tool <NUM> may be used in a variety of machining processes, and for machining of a variety of materials, it has been determined that use of cutting elements <NUM> having a PCD table <NUM> combined with a tool body <NUM> formed of a material comprising aluminum unexpectedly provides various benefits when machining a workpiece formed of titanium. While the exact mechanisms for improved efficiency and effectiveness of the machining of titanium are not entirely understood, it is believed that the use of an aluminum tool body may provide compliance, that such a configuration may provide enhanced thermal conductivity of the cutting tool, or some combination of the two characteristics may result in an enhanced performance of the machining process.

In some embodiments, the cutting elements may be beneficial in machining other thermal resistance materials. For example, in some embodiments, the cutting elements <NUM> of the present disclosure may provide advantages in machining materials having a thermal conductivity of less than approximately <NUM> watts per meter-Kelvin (W/m·K). In some embodiments, the cutting elements <NUM> of the present disclosure may be beneficial in machining materials having a thermal conductivity of less than approximately <NUM> W/m·K. In some embodiments, the cutting elements <NUM> of the present disclosure may be beneficial in machining materials having a thermal conductivity of less than approximately <NUM> W/m·K.

Referring now to <FIG>, a cutting element <NUM> according to another embodiment of the present disclosure is provided. The cutting element <NUM> may be formed of superhard, superabrasive materials. For example, the cutting element <NUM> includes polycrystalline diamond. As with previously described embodiments, the cutting element <NUM> includes a superhard, superabrasive table <NUM> defining the working surface <NUM>. In some embodiments, the cutting element <NUM> may comprise a PCD table <NUM> with no substrate or other structure attached thereto. In other words, in some embodiments, as previously noted, the cutting element <NUM> may consist of, or it may consist essentially of a superhard, superabrasive table, such as a PCD table <NUM>. In such an embodiment, the table may be initially formed with a substrate during an HPHT process (with the substrate providing a catalytic material such as previously described), and the substrate may be removed after the HPHT process. In other embodiments, the table <NUM> may be formed by mixing a catalytic material with diamond powder or otherwise providing a catalytic material prior to an HPHT process.

The table <NUM> includes a relatively "thick diamond" table which exhibits a thickness (i.e., from the working surface <NUM> to the lower, opposing surface <NUM>) that is <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch) or greater. In other embodiments, the table <NUM> exhibits a thickness of approximately <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch) or greater or <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch) or greater.

In one embodiment, the table <NUM> exhibits a thickness between <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch) and <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch). In one embodiment, the table <NUM> exhibits a thickness between approximately <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch) and <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch). In one embodiment, the table <NUM> exhibits a thickness between <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch) and <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch). In one embodiment, the table <NUM> exhibits a thickness between <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch) and <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch). In one embodiment, the table <NUM> exhibits a thickness between approximately <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch) and <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch). In one embodiment, the table <NUM> exhibits a thickness between <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch) and <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch). In one embodiment, the table <NUM> exhibits a thickness between <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch) and <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch). In one embodiment, the table <NUM> exhibits a thickness between <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch) and <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch). In one embodiment, the table <NUM> exhibits a thickness between <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch) and <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch). In one embodiment, the table <NUM> exhibits a thickness between <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch) and <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch).

As depicted in <FIG>, the cutting elements <NUM> may be configured to exhibit a substantially square outer profile when viewed from above (i.e., as seen specifically in <FIG>). Such a geometry provides multiple cutting edges which may be indexed relative to a cutting tool body <NUM> for extended service of the cutting elements <NUM>. In one embodiment, the cutting element <NUM> may have a face that exhibits a substantially square profile that exhibits a width W of <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch) and <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch). In another embodiment, the width W may be <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch) and <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch). In another embodiment, the width W may be <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch) and <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch). In another embodiment, the width W may be <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch) and <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch). In another embodiment, the width W may be <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch) and <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch). In another embodiment, the width W may be <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch). In another embodiment, the width W may be <NUM>,<NUM> x <NUM>-<NUM> m (<NUM> inch). In some embodiments, the square profile may include rounded or chamfered corners or transitions between sides.

As previously noted, other shapes and outer profiles are contemplated including, for example, circular, curved, triangular, rhombus, hexagonal, octagonal, and other regular or irregular polygons.

As seen in <FIG>, the cutting elements <NUM> also include an opening <NUM> formed in the table <NUM> to accommodate a fastener and/or a clamping element for coupling of the cutting element <NUM> with a cutting tool body <NUM>. The opening <NUM> may include a countersunk region <NUM> (or a counter bore, depending on the type of fastener being used) to enable a fastener and/or clamping element to be positioned flush with or below the working surface <NUM> of the table <NUM> when the cutting element <NUM> is coupled with a cutting tool body <NUM>.

Features for breaking chips of material that are being removed from the workpiece when engaged by the rotating cutting tool are also provided in the cutting elements <NUM>. The cutting elements include formations or structures referred to as chip breakers as has been previously described.

The table <NUM> may be formed in accordance with methods and techniques previously described herein and may include features and characteristics similar to those described herein with respect to other embodiments.

The PCD table <NUM> include a plurality of directly bonded-together diamond grains exhibiting diamond-to-diamond bonding therebetween (e.g., sp3 bonding), which define a plurality of interstitial regions. A portion of the interstitial regions of the PCD table may include a metal-solvent catalyst or a metallic infiltrant disposed therein that is infiltrated from a substrate or from another source during fabrication. For example, the metal-solvent catalyst or metallic infiltrant may be selected from iron, nickel, cobalt, and alloys of the foregoing. In some embodiments, the PCD table <NUM> may further include thermally-stable diamond in which the metal-solvent catalyst or metallic infiltrant has been partially or substantially completely depleted (e.g., region <NUM> shown in <FIG>) from a selected surface or volume of the PCD table, such as via an acid leaching process. Thermally-stable PCD may also be sintered with one or more alkali metal catalysts. In some embodiments, a catalyst-depleted region <NUM> may exhibit a depth that is substantially conformal with an outer surface of the PCD table <NUM>, such as shown in <FIG> and <FIG>. In other embodiments, the catalyst-depleted region <NUM> may generally extend a desired depth from a plane extending through the uppermost portions of the table <NUM> (e.g., through the peripheral edges of the working surface <NUM> and/or through the upper surface of the lip <NUM>). Thus, removal of the catalyst or infiltrant may be done prior to or after the forming of the structures and features (e.g., chip breakers <NUM>, opening <NUM>, etc.). As previously noted, in some embodiments, catalyst material may be removed from substantially the entire PCD table <NUM>, such as shown in <FIG>.

As discussed above, in some embodiments, the table <NUM> is leached to deplete a metal-solvent catalyst or a metallic infiltrant therefrom in order to enhance the thermal stability of the table <NUM>. The PCD table <NUM> is leached to remove at least a portion of the metal-solvent catalyst that was used to initially sinter the diamond grains to form a leached thermally-stable region <NUM>, from a working region thereof to a selected depth. The leached thermally-stable region may extend inwardly from the working surface <NUM> to a selected depth. In an embodiment, the depth of the thermally-stable region may be about <NUM> to about <NUM>,<NUM>. More specifically, in some embodiments, the selected depth is about <NUM> to about <NUM>, about <NUM> to about <NUM>, or about <NUM> to about <NUM>. The leaching may be performed in a suitable acid, such as aqua regia, nitric acid, hydrofluoric acid, or mixtures of the foregoing.

Referring briefly to <FIG>, a cutting element <NUM> is shown with a different cross-sectional profile. The cutting element <NUM> may include features and aspects such as described hereinabove with respect to other embodiments. For example, the cutting element <NUM> includes an opening <NUM> formed in a table <NUM> to accommodate a fastener and/or a clamping element for coupling of the cutting element <NUM> with a cutting tool body <NUM>. The opening <NUM> may include a countersunk region <NUM> (or a counter bore, depending on the type of fastener <NUM> being used) to enable a fastener and/or clamping element to be positioned flush with or below the working surface <NUM> of the table <NUM> when the cutting element <NUM> is coupled with a cutting tool body <NUM>. In the embodiment shown in <FIG>, the countersunk region <NUM> includes a counterbore which may be formed, in the profile shown, to provide a wall 219A and a floor 219B formed substantially at right angles relative to each other, and configured to accept the head <NUM> of a fastener <NUM>. The fastener <NUM>, including the head <NUM> of the fastener, may be configured to, at least in part, be substantially congruent with, conformal with, or otherwise correspond in size and shape with the counterbore or countersunk region. For example, as shown, the cross-sectional profile of the head <NUM> of the fastener <NUM> correlates or is congruent with the cross-sectional profile of the counterbore region. In other embodiments, for example, both the head of a fastener and the countersunk region by be tapered, stepped, or a combination of geometric shapes or features in a corresponding and at least partially conformal manner.

Features for breaking chips of material that are being removed from the workpiece when engaged by the rotating cutting tool <NUM> are also provided in the cutting element <NUM>. The cutting element <NUM> includes formations or structures referred to as chip breakers as has been previously described.

The PCD table <NUM> includes a plurality of directly bonded-together diamond grains exhibiting diamond-to-diamond bonding therebetween (e.g., sp3 bonding), which define a plurality of interstitial regions. A portion of the interstitial regions of the PCD table may include a metal-solvent catalyst or a metallic infiltrant disposed therein that is infiltrated from a substrate or from another source during fabrication. For example, the metal-solvent catalyst or metallic infiltrant may be selected from iron, nickel, cobalt, and alloys of the foregoing. In some embodiments, the PCD table <NUM> may further include thermally-stable diamond in which the metal-solvent catalyst or metallic infiltrant has been partially or substantially completely depleted from a selected surface or volume of the PCD table, such as via an acid leaching process. Locations, sizes, depths and configurations of catalyst depleted areas may be formed similar to those described above with respect to other embodiments including removal of catalyst material from substantially the entire table <NUM>.

Claim 1:
A cutting tool (<NUM>) comprising:
a body (<NUM>);
at least one cutting element (<NUM>) associated with the body (<NUM>), the at least one cutting element (<NUM>) comprising a superhard table (<NUM>) comprising polycrystalline diamond, wherein the superhard table (<NUM>) includes a plurality of diamond grains exhibiting diamond-to-diamond bonding therebetween, with a metal-solvent catalyst infiltrating at least some interstitial spaces between the diamond grains, and wherein the superhard table (<NUM>) has a region (<NUM>) where the metal-solvent catalyst is depleted from interstitial spaces between the diamond grains, with the region (<NUM>) forming a chip breaking feature (<NUM>) having a declining ramped surface portion (<NUM>) formed within the superhard table (<NUM>),
characterized in that:
the superhard table (<NUM>) exhibits a thickness of at least <NUM> x <NUM>-<NUM> m (<NUM> inches);
the declining ramped surface portion (<NUM>) formed within the superhard table (<NUM>) extends radially inward from an outer periphery of the superhard table (<NUM>) which defines a cutting edge (160A); and
the chip breaking feature (<NUM>) has an angled or curved return portion (<NUM>) that leads up to a protruding lip (<NUM>) positioned adjacent to and surrounding an opening (<NUM>) formed in the superhard table (<NUM>) for accommodating a fastener to couple the cutting element (<NUM>) to the body (<NUM>), with the angled or curved return portion (<NUM>) connecting the declining ramped surface portion (<NUM>) to the protruding lip (<NUM>).