Method of manufacturing a tool part

Abstract

The present disclosure relates to a method of making a shaped tool part from a precursor sintered body comprising polycrystalline diamond (PCD). The sintered body has a sheet of PCD bonded to a substrate, and the sheet of PCD varies in depth. The resulting shaped tool part therefore also has a PCD layer that varies in depth. A method of making a shaped tool part comprising polycrystalline diamond (PCD), the method comprising the steps of: h. adding a diamond feedstock to a refractory cup; i. adding a preformed sintered carbide body to the refractory cup adjacent the diamond feedstock; j. compacting the diamond feedstock and sintered carbide body to form a green body; k. sintering the green body at a temperature between 1400 °C and 2100 °C and at a pressure of at least 7 GPa for at least 30 seconds to form a sintered PCD precursor body comprising a sheet of PCD sinter-bonded at an interface to a sintered carbide substrate.

Description

Technical Field

[0001] This disclosure relates to shaped superhard tool components for cutting wear-resistant products, particularly to methods of manufacturing said shaped tool components, and even more particularly to those comprising polycrystalline diamond. Background Technology

[0002] Hard or abrasive workpiece materials, such as metal alloys, ceramics, cermets, certain composites, and stone, may require machining using tools with hard or superhard cutting tips. Sintered tungsten carbide is the most widely used tool material for machining hard workpiece materials and is both hard and tough. Polycrystalline diamond (PCD) and polycrystalline cubic boron nitride (PCBN) are superhard materials that can be used to machine certain metal alloys widely used in, for example, the automotive industry. Superhard materials are extremely hard and have a Vickers hardness of at least about 25 GPa. However, the strength and toughness of superhard materials are typically not as good as sintered carbide materials, and therefore, they may be more prone to fracture and splintering than hard metals. Superhard tool inserts may include superhard structures bonded to a support substrate (“backing”), which is most typically formed from sintered tungsten carbide. Tool inserts with complex geometries are not common due to the costs associated with the production and subsequent shaping of PCD.

[0003] There is a need to develop a more economical method for manufacturing forming tool inserts using PCD. Summary of the Invention

[0004] According to the present invention, a method for manufacturing a forming tool component comprising polycrystalline diamond (PCD) is provided, the method comprising the following steps:

[0005] a. Add the diamond raw material to the refractory cup;

[0006] b. Add the pre-formed sintered carbide body to the refractory cup adjacent to the diamond raw material;

[0007] c. Compact the diamond raw material and the sintered carbide body to form a green body;

[0008] d. The green body is sintered at a temperature between 1400°C and 2100°C and at a pressure of at least 7 GPa for at least 30 seconds to form a sintered PCD precursor body comprising PCD sheets sintered and bonded to a sintered carbide substrate at the interface.

[0009] e. Longitudinally slice into the sintered PCD precursor body to produce one or more slice portions of the sintered PCD precursor body, each slice portion being a tool blank;

[0010] f. Remove one of the tool blanks from the remaining portion of the sintered PCD precursor body; and

[0011] g. Forming the tool blank into a forming tool component, wherein the thickness of the PCD sheet in the forming tool component varies at two or more laterally spaced locations on the sintered carbide substrate.

[0012] Optional and / or preferred features of the invention are provided in the dependent claims. Attached Figure Description

[0013] The invention will now be described more specifically by way of example only, with reference to the accompanying drawings, in which:

[0014] Figure 1 This is a schematic perspective view of a part of a circular saw used for cutting wood;

[0015] Figure 2 It is used for Figure 1 A schematic side view of the tool insert of a circular saw;

[0016] Figure 3 This is a schematic flowchart illustrating a method for manufacturing tool inserts;

[0017] Figure 4 This is a schematic flowchart illustrating an alternative method for manufacturing tool inserts;

[0018] Figure 5 This is a schematic flowchart illustrating yet another alternative method for manufacturing tool inserts;

[0019] Figure 6 This is a schematic perspective view of the first sintered PCD precursor body;

[0020] Figure 7 yes Figure 6 A side view of the sintered PCD precursor body, which in particular shows the PCD sheet (table) sintered to the carbide substrate at the interface.

[0021] Figure 8 yes Figure 6 A front view of the sintered PCD precursor body;

[0022] Figure 9 yes Figure 6 A plan view of the sintered PCD precursor body;

[0023] Figure 10 From Figure 6A schematic side view of the tool blank cut from the sintered PCD precursor body, with superimposed tool outlines, particularly showing the excess material of the PCD sheet intended for removal.

[0024] Figure 11 After removing excess materials Figure 10 A schematic side view of the forming tool component;

[0025] Figure 12 This is a schematic perspective view of the PCD precursor body after the second sintering.

[0026] Figure 13 yes Figure 12 Side view of the sintered PCD precursor body;

[0027] Figure 14 yes Figure 12 A front view of the sintered PCD precursor body;

[0028] Figure 15 yes Figure 12 A plan view of the sintered PCD precursor body;

[0029] Figure 16 From Figure 12 A schematic side view of the tool blank cut from the sintered PCD precursor body, showing different superimposed tool profiles, particularly illustrating the excess material of the PCD sheet intended for removal.

[0030] Figure 17 After removing excess materials Figure 16 A schematic side view of the forming tool component;

[0031] Figure 18 a to 18c are a set of three schematic diagrams that illustrate the forming of an L-shaped backing component from a tool blank;

[0032] Figure 19 a to 19c are a set of three schematic diagrams that illustrate the forming of a triangular backing component from a tool blank;

[0033] Figure 20 Sample A from a 10mm green test is shown after being removed from the HPHT press, in which the PCD sheet is delaminated from the substrate, and Figure 20 b shows that the layered PCD sheet and substrate have been separated;

[0034] Figure 21 Sample B from the 20mm green test is shown after being removed from the HPHT press;

[0035] Figure 22 a shows sample 1 after sintering using the standard sintering curve, and Figure 22b shows sample 2 with an extended sintering curve;

[0036] Figure 23 a shows sample 3 and Figure 23 b shows sample 4, both of which were sintered using an extended sintering curve;

[0037] Figure 24 a shows sample 3 in which PCD sheets are sintered and bonded to a substrate and subsequently processed. Figure 24 b shows sample 4 after stratification and subsequent processing, and Figure 24 c shows a standard oil and gas cutter used for comparison purposes;

[0038] Figure 25 The diagram shows two PCD bodies intentionally obtained through layering, subsequently machined into an oil and gas tool configuration; and

[0039] Figure 26 It shows the effect after chemical leaching Figure 25 One of the knives.

[0040] In all the accompanying drawings, the same reference numerals refer to the same corresponding features. Detailed Implementation

[0041] refer to Figure 1 and 2 A circular saw 10 for cutting abrasion-resistant wood products (such as engineered wood flooring) includes a plurality of tool inserts 12 brazed to the periphery of a blade base 14. Each tool insert 12 is derived from a shaped tool component, as explained in more detail below. Each tool insert 12 includes a PCD sheet 16 sintered to a sintered carbide substrate 18 at an interface 20. The tool insert 12 is provided with a rake face 22 of the PCD sheet 16 facing the rotation direction of the saw 10 in use, wherein the cutting edge 24 is arranged in the radially outermost position, enabling it to cut a workpiece (not shown) when the saw 10 rotates in use.

[0042] In the longitudinal section, interface 20 comprises a series of interconnected arcuate and linear interface segments. The ratio of PCD flakes 16 to sintered carbide substrate 18 within the tool insert 12 varies from a first end 26 to a second end 28, which is spaced apart from the first end 26. The first end is located at the cutting edge 24. Near the cutting edge 24, the ratio of PCD flakes 16 to the carbide substrate 18 is highest, and it gradually decreases towards the second end 28. This arrangement allows the PCD 16 to be distributed only in the areas actually needed during use, close to the cutting edge, thereby reducing the production cost of the tool insert.

[0043] Now go to Figure 3 , 45. The production of the tool insert will now be described, wherein the following numbers correspond to the numbers used in the above figures.

[0044] S1. Add the diamond raw material to a cup made of refractory material such as niobium, tantalum, or molybdenum. Typically, the cup is cylindrical.

[0045] S1a. Optionally, a sintered carbide body is also added to the cup, adjacent to the diamond feedstock.

[0046] S1b. Optionally, the sintered carbide body is shaped before being added to the cup.

[0047] S2. The diamond raw material and sintered carbide body (if present) are then compacted to form a green body. If desired, the compaction stage can be performed before placing the diamond raw material and sintered carbide body (if present) into the cup.

[0048] Degas the green to minimize deformation of the final shape. Again, this can be done before placing the green in the tank.

[0049] After degassing, the green body and cup are then assembled into a "pre-composite body" using additional cup-shaped material.

[0050] S3. The pre-composite matrix is ​​then sintered in a high-pressure, high-temperature (HPHT) capsule within an HPHT belt press or an HPHT six-sided top press at a temperature between 1400°C and 1800°C for at least 30 seconds. This forms the sintered PCD precursor matrix.

[0051] S4. Then, as soon as reasonably possible, remove the sintered PCD precursor body from the HPHT capsule and allow it to cool to room temperature.

[0052] S5. The sintered PCD precursor body is then longitudinally sliced ​​to produce one or more slice portions called “tool blanks”.

[0053] Depending on the end application, the thickness of each tool blank can vary. For example, a tool blank can be thicker, rectangular, cubic in shape, for end use in circular saw tool inserts. Alternatively, a tool blank can be thinner and plate-shaped, for example, for end use in turning or milling tool elements.

[0054] S6. Remove the tool blank from the remaining portion of the sintered PCD precursor body.

[0055] S7. Use electrical discharge machining (EDM) or laser cutting to shape the tool blank into its final form (forming the tool part).

[0056] Example

[0057] refer to Figures 6 to 11 The second forming tool component is typically produced according to the above method, including optional steps 1a) and 1b).

[0058] The sintered carbide body 18 contains sintered tungsten carbide and has an initial diameter of about 21 mm and a maximum height of 12 mm.

[0059] Before being inserted into the refractory cup, the sintered carbide body 18 is formed by EDM into a generally horizontal planar first portion 30, which extends into a downwardly sloping planar second portion 32, as shown. Figure 7 As shown. The first part 30 of the plane extends horizontally between points P and Q, which are located on the periphery, with point Q being radially inside point P. The second part 32 of the plane slopes axially downward between points Q and R, with point R located on the periphery and circumferentially spaced from point P.

[0060] In this example, the maximum height of the sintered carbide body taken at point P is the initial height of 12 mm, measured starting from the bottom of the sintered carbide body 18. The minimum height of the carbide body taken at point R is 4 mm, again measured starting from the bottom.

[0061] Diamond raw material with an average particle size of 22 μm was used and cobalt was added.

[0062] After HPHT sintering, the sintered PCD precursor body (generally indicated by 34) is removed from the HPHT capsule and allowed to cool to room temperature. The outer cup-shaped material is ground away to expose the inner sintered PCD precursor body 34.

[0063] The sintered PCD precursor body 34 is longitudinally sliced ​​using EDM to separate a portion from the remainder. The sliced ​​portion is then removed to provide a tool blank 36. The tool blank 36 has a generally rectangular planar shape and a thickness not exceeding 8 mm.

[0064] Using EDM again, the tool profile 38 is machined into the PCD sheet 16 of the tool blank 36 and the unwanted PCD 40 is removed to produce the formed tool part 42. Figure 10 and 11 An example of a formed tool part 42 with an overly simplistic tool profile 36 is given and is not intended for practical use. Tool profile 38 of any shape, size, or orientation can be used. Importantly, tool profile 38 follows the overall shape of the sintered carbide substrate 18. As the height of the substrate 18 changes, the height of the PCD sheet 16 above it also changes, as measured from the bottom of the sintered carbide substrate 18. Given the configuration of the sintered carbide substrate 18, a much greater depth of the PCD sheet 16 is achievable, but it is unnecessary to impose additional depth where it is unnecessarily large.

[0065] Example

[0066] refer to Figures 12 to 17 The third forming tool component is typically produced according to the above method, including optional steps 1a) and 1b). The forming tool component originates from its sintered PCD precursor body, which is generally indicated by 44. The third forming tool component is similar to the second variant, except that its shape is trimmed before the sintered carbide body 18 is inserted into the refractory cup.

[0067] like Figure 16 and 17 As best viewed, the sintered carbide substrate 18 below includes a generally horizontal planar first portion 30 and a downwardly sloping, arcuate second portion 46, rather than a sloping planar second portion 32. Again, the shape of the PCD sheet 16 generally follows the shape of the shaped substrate 18 below.

[0068] This method of manufacturing forming tool parts only requires a PCD sheet of the desired thickness; nothing else is needed. Using conventional methods, a much thicker PCD sheet would be required to achieve the desired depth on the forming tool part, resulting in significantly more unusable PCD sheet.

[0069] Any tool profile can be provided in the PCD sheet. For example, in a transverse section, the tool profile can include segments that are any of the following: arcuate, linear, straight, zigzag, or sinusoidal. Multiple segment shapes such as these or any combination thereof can be used.

[0070] In this third variant, a second tool profile 48, different from the first tool profile 38 mentioned above, is machined into the PCD sheet 16 of the resulting tool blank 50. Unwanted PCD 40 material is removed from the PCD sheet 16 to produce another formed tool part 52.

[0071] The outline of the PCD sheet 16 does not need to be the same as the outline of the sintered carbide substrate 18 below, as shown in the second and third variations. However, the outline of the PCD sheet 16 may be the same as the outline of the sintered carbide substrate 18 below, as shown in the first variation.

[0072] Figure 18 a to 18c and Figure 19 A through 19c demonstrate how a backing (i.e., a carbide substrate) and partially backed tool parts can be partially formed from a tool blank. Using a method of slicing 2D tool blanks from a 3D sintered PCD precursor body, irregularly shaped tool parts can be manufactured with minimal loss.

[0073] In all variations, forming is not limited to creating contours on PCD sheets. Forming can also extend to creating contours on substrates. Most importantly, forming also extends to machining the contours of shaped tool parts that are entirely contained within the footprint of the tool blank. For example, the entire letter 'A' can be formed from a tool blank. Any desired form of shaped tool part can be formed from a tool blank, regardless of whether the sintered PCD precursor body contains a sintered carbide substrate.

[0074] Although several examples including sintered carbide bodies / substrates have been referenced, the sintered carbide body can be omitted from the method of manufacturing the formed tool part. In practice, forming can be limited to shaping a tool blank composed of sintered PCD, which is sliced ​​from a sintered PCD precursor body. In this case, the formed tool part can take any form.

[0075] Relatedly, during their development work, the inventors investigated increasingly deeper PCD sheets. Two samples were produced, each with a planar sintered carbide substrate. In sample A, the green body was cut to a depth of 10 mm. In sample B, the green body was cut to a depth of 20 mm. Both green bodies were then sintered.

[0076] Although sample A was successfully sintered, the PCD layer delaminated from the substrate. Figure 20 a shows sample A from the press, and Figure 20 b shows the separated same PCD sheet and substrate. The delamination may be due to high stress associated with PCD volume collapse, or simply because the synthesis conditions were slightly too hot.

[0077] In sample B, careful examination revealed the possible presence of two waves of cobalt infiltration: one flowing uniformly across the substrate, and the other flowing around the periphery and top surface – see [link to sample B]. Figure 21 This left the sintered lower half of the PCD layer and the cracked upper half, as well as a soft, unsintered core.

[0078] To address the problem of soft, unsintered cores resulting from attempts to achieve ultra-thick (>10 mm) PCD sheets, numerous variables were investigated. These included synthesis conditions (pressure, temperature, and time), the use of degassing, pre-compaction load and temperature, different substrate depths, different HPHT press bladder settings, and the use of a cobalt interlayer in the green body between the diamond feedstock and the carbide substrate.

[0079] In a later phase of the work, four additional samples were prepared – see Table 1.

[0080] sample Detailed description 1 Diamond feed with 10% cobalt mixture and no degassing 2 Diamond feed with Co foil at the interface and without degassing 3 Diamond feed with 10% cobalt mixture and degassed 4 Diamond feed with Co foil at the interface and degassed

[0081] Table 1

[0082] Sample 1, prepared using sintering curve 1, showed no improvement compared to the previous stage and had a soft core. For sample 2, an alternative sintering curve was chosen, which included an extended sintering time. Sample 2 was mostly sintered throughout. Figure 22 a shows sample 1 and Figure 22 b shows sample 2, both of which were after sintering.

[0083] After degassing, samples 3 and 4 were sintered using a second longer sintering curve. Sample 3 had a fully sintered ultra-thick PCD sheet without any visible defects. Sample 4 was also fully sintered, but the PCD layer delaminated from the substrate, which was thought to be due to excessive Co foil at the interface. Figure 23 a shows sample 3 and Figure 23 b shows sample 4, both of which were after sintering.

[0084] For subsequent characterization tests, samples 3 and 4 had their cup material removed. Figure 24 a shows sample 3. Figure 24 b shows the process after layering, and the machining of it to the same overall shape and size as a standard oil and gas cutting tool. Figure 24 c) Matched sample 4. Figure 24 The tool in c has a diameter of 16mm and a PCD sheet height of 3.5mm. In comparison, Figure 24 Sample 4 in b has a diameter of 16 mm and a PCD sheet height of 12 mm.

[0085] It was found that thermal precompaction was necessary for the successful sintering of samples with ultra-thick PCD bodies. These specific samples were sintered at 5.5 GPa and a temperature of approximately 1400 °C for 20 minutes. However, a wider operating window is feasible. Precompaction occurs at temperatures ranging from 1300 °C to 1500 °C, pressures ranging from 5 to 8 GPa, and durations ranging from 15 to 25 minutes. The compaction stage is characterized by the absence or minimal presence of catalyst / binder materials, such as cobalt. The amount is insufficient for complete sintering. This is primarily added later and can include, in any or more of the following ways: the use of cobalt foil, for example, a layer of cobalt powder at the interface between the diamond feed and the substrate, and the use of a sintered carbide substrate containing cobalt. Furthermore, the precompaction step occurs during the first HPHT press run, and sintering occurs during a second, different HPHT press run requiring separate capsule assemblies.

[0086] The inventors have discovered an unexpected new method for obtaining ultra-thick PCD bodies. This can be based on the results of Sample 3 with a backing (i.e., using a substrate) or on the results of Sample 4 without a backing (i.e., freestanding). In contrast, until now, oil and gas cutting tools with PCD sheets only up to 5 to 6 mm deep have been obtained. The impact on cutting tools used in oil and gas drilling is significant because PCD sheets (as in Sample 4, layered with a substrate) can be machined into freestanding cutting tools.

[0087] For further investigation, diamond feedstock containing particles with an average particle size of 17 μm was used. Additional samples were produced and machined into cutting tools, neither of which had a substrate – see [link to sample]. Figure 25 The sample is then sent for chemical leaching (the process of removing cobalt from the interstitial regions of the PCD matrix). Removing cobalt from the diamond lattice structure makes the PCD more heat-resistant and therefore more suitable for oil and gas drilling operations.

[0088] The removal of the tungsten carbide substrate has facilitated new and faster leaching methods for cutting tools. This method eliminates the need for complex fixtures to protect the substrate, and the tool can be placed in a sealed container of hydrochloric acid (HCl) and heated to temperatures significantly higher than standard cutting tools. Figure 26 As can be seen, the 16mm diameter blade, when immersed from all directions, leaves only a small amount of cobalt in the center, which is an excellent result.

[0089] The immersed blade was then removed for characterization testing. The blade performed very well in subsequent performance tests.

[0090] While the invention has been specifically shown and described by reference to examples, those skilled in the art will understand that various changes in form and detail may be made without departing from the scope of the invention as defined by the appended claims.

[0091] definition

[0092] The following is a brief explanation of some of the standard terms and concepts used in this article.

[0093] PCD contains a large number of inter-grown diamond grains that form a framework that defines the spaces between the diamond grains. PCD materials typically contain at least 80 vol.% diamond and are obtained through HPHT sintering in the presence of a sintering aid (also known as a catalyst material for diamond). The catalyst material for diamond should be understood as a material that promotes the direct co-existence of diamond grains under pressure and temperature conditions where diamond is thermodynamically more stable than graphite.

[0094] Catalyst materials used for diamond typically include Group VIII elements, and common examples are cobalt, iron, nickel, and certain alloys, including alloys of any of these elements. PCD can be formed on a cobalt-sintered tungsten carbide substrate, which can provide a source of cobalt catalyst material for the PCD. During the bulk of the sintering of the PCD material, the components of the sintered carbide substrate (such as cobalt in the case of a cobalt-sintered tungsten carbide substrate) liquefy and flow from regions adjacent to the volume of the diamond particles to interstitial regions between the diamond particles. Cobalt serves as a catalyst to facilitate the formation of bonded diamond grains. Optionally, a metal-solvent catalyst can be mixed with the diamond particles before subjecting the diamond particles and substrate to the HPHT process. The interstitials within the PCD material can be at least partially filled with catalyst material. Thus, the symbiotic diamond structure includes the original diamond grains and newly precipitated or regrown diamond phases bridging the original grains. In the final sintered structure, residual catalyst / solvent material is typically retained within at least some of the interstitials between the sintered diamond grains.

[0095] A known problem with conventional PCD briquettes is their susceptibility to thermal degradation when exposed to elevated temperatures during cutting and / or abrasion applications. This is believed to be at least partly due to residual solvent / catalyst material in the interstitial spaces of the microstructure. This residual solvent / catalyst material is considered to have an adverse effect on the performance of the PCD briquettes at high temperatures due to the difference in thermal expansion characteristics between the interstitial solvent metal catalyst material and the intergranular bonded diamond. This differential thermal expansion is known to occur at temperatures around 400°C and is believed to cause diamond-to-diamond bonding fracture, which can ultimately lead to cracks and debris formation within the PCD structure. Fracture or breakage in the PCD sheet can degrade the mechanical properties of the cutting element containing the PCD sheet or cause the cutting element to fail during drilling or cutting operations, rendering the PCD structure unsuitable for further use.

[0096] As used herein, the “front side” of a tool insert is a side that includes a “front face”, which is one or more surfaces of the tool over which debris flows during use. As used herein, “debris” is a piece of workpiece removed from a working surface by a machine tool in use. As used herein, “cutting edge” is a cutting edge of the front face designed for making cuts.

[0097] As used in this article, "machining" is the selective removal of material from a body (called a workpiece). Sawing and cutting are examples of machining operations.

Claims

1. A method for manufacturing a forming tool component comprising polycrystalline diamond (PCD), the method comprising the following steps: a. Add the diamond raw material to the refractory cup; b. Add the pre-formed sintered carbide body to the refractory cup adjacent to the diamond raw material; c. The diamond raw material and the sintered carbide body are compacted to form a green body, and the compaction occurs at a temperature in the range of 1300°C and 1500°C and at a pressure in the range of 5 to 8 GPa. d. Degas the green body; then proceed with a separate step; e. Sinter the green body at a temperature between 1400°C and 2100°C and at a pressure of at least 7 GPa for at least 30 seconds to form a sintered PCD precursor body comprising a PCD sheet sintered and bonded to a sintered carbide substrate at an interface. f. Longitudinally slice into the sintered PCD precursor body to produce one or more slice portions of the sintered PCD precursor body, each slice portion being a tool blank; g. Remove one of the tool blanks from the remaining portion of the sintered PCD precursor body; as well as h. The tool blank is formed into a forming tool component, wherein the thickness of the PCD sheet in the forming tool component varies at two or more laterally spaced locations on the sintered carbide substrate.

2. The method as described in claim 1, wherein, The thickness of the PCD sheet in the forming tool component is between 2 and 20 mm.

3. The method as described in claim 1 or 2, wherein, The interface in the transverse section includes a series of interconnected interface segments, which are any of the following: arc-shaped, linear, or straight.

4. The method of claim 1, wherein, The tool blank is planar.

5. The method of claim 1, wherein, The tool blank is a rectangular cube.

6. The method of claim 1, wherein, The tool blank is a parallelepiped.

7. The method of claim 1, wherein, Shaping the tool blank includes forming a tool profile.

8. The method of claim 7, wherein, Forming the tool blank includes forming a tool profile on or in at least one surface or peripheral edge of the tool blank.

9. The method of claim 8, wherein, The tool profile is set on or in the top surface and / or side surface of the PCD sheet.

10. The method of claim 8, wherein, The tool profile is completely set within the coverage area of ​​the tool blank.

11. The method of claim 7, wherein, The tool profile in the transverse section comprises a series of interconnected profile segments, which are any of the following: arc-shaped, linear, straight, serrated, or sinusoidal.

12. The method of claim 1, wherein, The step of forming the sintered carbide body and / or the tool blank includes EDM cutting.

13. The method of claim 1, wherein, Forming the sintered carbide body and / or the tool blank includes laser cutting.

14. The method of claim 1, further comprising shaping the tool blank into an insert for a circular saw.

15. The method of claim 1, further comprising shaping the tool blank into an insert for dressing a grinding wheel.

16. The method of claim 1, wherein, The sintered PCD precursor body is cylindrical.

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