METHOD FOR PRODUCING A GREEN COMPOSITION AND METHOD FOR FURTHER PROCESSING THE GREEN COMPOSITION INTO A MACHINING SEGMENT

Description

Technisches Gebiet

[0001] The present invention relates to a method for producing a green compact according to the preamble of claim 1 and a method for further processing a green compact into a processing segment according to the preamble of claim 4. Stand der Technik

[0002] Machining tools, such as core drill bits, saw blades, stock removal discs, and abrasive chains, comprise machining segments that are attached to a tubular, disc-shaped, or ring-shaped base body. The machining segments are connected to the base body by welding, soldering, or gluing. Depending on the machining process of the machining tool, machining segments used for core drilling are called drilling segments, machining segments used for sawing are called sawing segments, machining segments used for stock removal are called stock removal segments, and machining segments used for abrasive cutting are called abrasive cutting segments.

[0003] Machining segments for core drill bits, saw blades, abrasive discs, and abrasive chains are manufactured from a matrix material and hard material particles. The hard material particles can be randomly distributed or arranged according to a defined particle pattern within the matrix material. For machining segments with randomly distributed hard material particles, the matrix material and the hard material particles are mixed, the mixture is poured into a suitable tool mold, and further processed into the machining segment. For machining segments with defined arrangement of hard material particles, a green compact is built up layer by layer from matrix material, into which the hard material particles are arranged according to the defined particle pattern.For machining segments that are to be welded to the base body of the machining tool, a structure consisting of a machining zone and a neutral zone has proven to be effective, as some combinations of matrix material and base body are not weldable. The machining zone is constructed from a first matrix material, and the neutral zone from a second matrix material that is different from the first matrix material and weldable to the base body.

[0004] Machining tools designed for wet machining of concrete materials, such as core drill bits, saw blades, removal discs, or abrasive chains, are only suitable to a limited extent for dry machining of concrete materials. Wet machining of concrete materials creates an abrasive concrete slurry that supports the machining process and causes the machining segments to self-sharpen during machining. The matrix material is removed by the abrasive concrete slurry, and new hard material particles are exposed. During dry machining of concrete materials, no abrasive concrete slurry can form that can support the machining process. The hard material particles quickly become blunt, and the machining rate decreases. Due to the lack of concrete slurry, the matrix material wears too slowly, and deeper-lying hard material particles cannot be exposed.

[0005] For the dry machining of concrete materials, machining segments are required in which the first hard material particles protrude from the first matrix material on the upper side. The greater the protrusion of the first hard material particles, the higher the machining rate that can be achieved with the machining segment. European patent application EP 3 670 041 relates to a method for producing a machining segment from a first matrix material and first hard material particles that are arranged according to a defined first particle pattern. The method is characterized in that a green compact is produced in which the first hard material particles protrude from the first matrix material on the upper side.The green compact is further processed with a special press die which has depressions in a pressing surface, whereby the arrangement of the depressions corresponds to the defined first particle pattern of the first hard material particles.

[0006] The known method for producing a machining segment has the disadvantage that further processing the green compact into a machining segment requires a special press die with recesses in the pressing surface, which is used during compaction or hot pressing. A special press die is required for each defined first particle pattern according to which the first hard material particles are arranged.

[0007] EP 0 754 106 A1 discloses a known method for producing a machining segment from a first matrix material and first hard material particles arranged according to a defined first particle pattern.

[0008] US 5,203,880 A discloses a known method for producing a green compact for a machining segment from a first matrix material and first hard material particles arranged according to a defined first particle pattern. The first matrix material is applied to the tool mold, the first hard material particles are arranged in the first matrix material according to the defined particle pattern, and the support material is then placed between the green compact and the tool mold. Darstellung der Erfindung

[0009] The object of the present invention is to develop a method for producing a green compact for a machining segment, with which machining segments can be produced that have a protrusion of the hard material particles on the upper side. Conventional tool components are to be used both in the production of the green compact and in the further processing of the green compact into the machining segment; the use of special tool components is to be avoided.

[0010] This object is achieved according to the invention in the method mentioned at the outset by the features of independent claim 1. Advantageous further developments are specified in the dependent claims.

[0011] The method for producing a green compact for a machining segment from a powdered or granular first matrix material and first hard material particles is characterized according to the invention by the steps: ▪ Applying a powdered or granular support material, wherein the support material is different from the first matrix material, ▪ Arranging the first hard material particles according to a defined particle pattern in the support material, wherein the first hard material particles are partially arranged in the support material, and ▪ Applying the first matrix material to the first hard material particles and the support material.

[0012] The method according to the invention for producing a green compact is characterized in that the green compacts are constructed in an upright position, i.e., the construction direction runs perpendicular to the height direction between the underside and top side of the processing segment. The protrusion of the first hard material particles on the top side of the processing segments is created using the powdered or granular support material, which is different from the first matrix material.

[0013] The term "support material" encompasses all materials used to construct machining segments into which hard material particles can be embedded. The support material is in powder or granular form and is different from the primary matrix material. It serves to completely embed the hard material particles in the powder or granular material.

[0014] Green compacts produced by the method according to the invention for producing a green compact can be further processed into processing segments using known methods for further processing the green compact. Known further processing methods include compacting the green compact by cold pressing or hot pressing into a compact, which is then further processed into a processing segment by free-form sintering or hot pressing, or further processing the green compact by free-form sintering or hot pressing into a processing segment.

[0015] Green compacts are further processed into the finished machining segment under the influence of heat through free-form sintering or hot pressing. The sintering temperature of the first matrix material determines the temperature to which the green compacts or pressed parts must be heated. The support material can retain its powder or granular state during further processing of the green compact into the machining segment (first variant) or support the sintering process as an infiltrate (second variant).

[0016] In a first variant, a support material is applied with a melting temperature higher than the sintering temperature of the first matrix material. If the melting temperature of the support material is higher than the sintering temperature of the first matrix material, the support material remains in its powder or granular state during heating and can be easily removed from the finished machining segment after the sintering process.

[0017] In a second variant, a support material is applied with a melting temperature lower than the sintering temperature of the first matrix material. If the melting temperature of the support material is lower than the sintering temperature of the first matrix material, the support material changes from its powder or granular state upon heating and liquefies before the first matrix material sinters. The liquid support material can be distributed throughout the first matrix material and support the sintering process as an infiltrate.

[0018] The invention further relates to a method for further processing a green compact produced using the method for producing a green compact into a machining segment, which is connected via a bottom side to a base body of a machining tool. In a green compact produced using the method for producing a green compact according to the invention, the first hard material particles have a projection on the top side relative to the first matrix material.

[0019] In a first embodiment, the green compact is compressed into a pellet under pressure, which is then further processed into a processing segment. The green compact is compressed into a pellet under pressure between a first press die, which forms the bottom of the processing segment, and a second press die, which forms the top of the processing segment.

[0020] Particularly preferably, the compact is further processed into the machining segment by free-form sintering or hot pressing. Since the first hard material particles in a green compact produced according to the invention are completely embedded in the powdered or granular support material, a conventional second press die can be used during hot pressing to form the upper side of the machining segment.

[0021] In a second embodiment, the green compact is further processed into the machining segment by free-form sintering or hot pressing. Since the first hard material particles in a green compact produced according to the invention are completely embedded in powdered or granular support material, a conventional second press die can be used during hot pressing to form the upper side of the machining segment. Ausführungsbeispiele

[0022] Embodiments of the invention are described below with reference to the drawing. These are not necessarily intended to show the embodiments to scale; rather, where useful for explanation, the drawing is schematic and / or slightly distorted. It should be noted that many modifications and changes to the form and detail of an embodiment can be made without departing from the general idea of ​​the invention. The general idea of ​​the invention is not limited to the exact form or detail of the preferred embodiment shown and described below, or to an object that would be limited compared to the object claimed in the claims. For given dimensioning ranges, values ​​lying within the stated limits are also intended to be disclosed as limit values ​​and can be used and claimed as desired.For the sake of simplicity, the same reference symbols are used below for identical or similar parts or parts with identical or similar functions.

[0023] They show: FIGS. 1A, B two variants of a machining tool designed as a core drill bit; FIGS. 2A, B two variants of a machining tool designed as a saw blade; FIG. 3 a machining tool designed as a removal disc; FIG. 4 a machining tool designed as a cutting-off chain; FIGS. 5A-C a green compact ( FIG. 5A ), which is compressed into a pellet ( FIG. 5B ) and is further processed into a processing segment ( FIG. 5C ); FIGS. 6A-D the production of the green body of the FIG. 5A using the method according to the invention for producing a green compact; FIG. 7A, green compact ( FIG. 7A ), which is further processed into a processing segment ( FIG. 7B ).

[0024] FIGN. 1A , Bshow two variants of a core drilling crown 10A, 10B The machining tool designed in FIG. 1A The core drill bit 10A shown is referred to as the first core drill bit and the one shown in FIG. 1B The core drilling crown 10B shown is referred to as the second core drilling crown; moreover, the first and second core drilling crowns 10A, 10B are summarized under the term "core drilling crown".

[0025] The first core drill bit 10A comprises several machining segments 11A, a tubular base body 12A and a tool holder 13A. The machining segments 11A used for core drilling are also referred to as drilling segments, and the tubular base body 12A is also referred to as the drill shaft. The drilling segments 11A are firmly connected to the drill shaft 12A, for example, by screwing, gluing, soldering, or welding.

[0026] The second core drill bit 10B comprises an annular machining segment 11B, a tubular base body 12B and a tool holder 13B. The annular machining segment 11B, which is used for core drilling, is also referred to as the drill ring, and the tubular base body 12B is also referred to as the drill shaft. The drill ring 11B is firmly connected to the drill shaft 12B, for example, by screwing, gluing, soldering, or welding.

[0027] The core drilling crown 10A, 10B is connected to a core drilling machine via the tool holder 13A, 13B and is rotated by the core drilling machine in one direction of rotation 14 around an axis of rotation 15 During the rotation of the core drill bit 10A, 10B around the rotation axis 15, the core drill bit 10A, 10B is moved along a feed direction 16into a workpiece to be machined, with the feed direction 16 running parallel to the rotation axis 15. The core drilling crown 10A, 10B creates a drill core and a drill hole in the workpiece to be machined.

[0028] The drill shaft 12A, 12B is in the embodiment of the FIGN. 1A , B are formed in one piece and the drill segments 11A or the drill ring 11B are firmly connected to the drill shaft 12A, 12B. Alternatively, the drill shaft 12A, 12B can be formed in two parts from a first drill shaft section and a second drill shaft section, wherein the drill segments 11A or the drill ring 11B are firmly connected to the first drill shaft section and the tool holder 13A, 13B is firmly connected to the second drill shaft section. The first and second drill shaft sections are connected to one another via a detachable connecting device. The detachable connecting device is designed, for example, as a plug-and-turn connection, as described in EP 2 745 965 A1 or EP 2 745 966 ​​A1. The design of the drill shaft as a one-piece or two-piece drill shaft has no influence on the structure of the drill segments 11A or the drill ring 11B.

[0029] FIGN. 2A , B show two variants of a saw blade 20A, 20B trained machining tool. The FIG. 2A The saw blade 20A shown will be referred to as the first saw blade and the one shown in FIG. 2B The saw blade 20B shown is referred to as the second saw blade, and the first and second saw blades 20A, 20B are collectively referred to as the "saw blade".

[0030] The first saw blade 20A comprises several machining segments 21A, a disc-shaped base body 22A and a tool holder. The processing segments 21A, which are used for sawing, are also referred to as saw segments, and the disc-shaped base body 22A is also referred to as the base blade. The saw segments 21A are firmly connected to the base blade 22A, for example, by screwing, gluing, soldering, or welding.

[0031] The second saw blade 20B comprises several machining segments 21B, a ring-shaped base body 22Band a tool holder. The machining segments 21B, which are used for sawing, are also referred to as saw segments, and the ring-shaped base body 22B is also referred to as a ring. The saw segments 21B are firmly connected to the ring 22B, for example, by screwing, gluing, soldering, or welding.

[0032] The saw blade 20A, 20B is connected to a saw via the tool holder and is rotated by the saw in one direction during sawing operation 24 around an axis of rotation 25 During the rotation of the saw blade 20A, 20B about the rotation axis 25, the saw blade 20A, 20B is moved along a feed direction, wherein the feed direction runs parallel to the longitudinal plane of the saw blade 20A, 20B. The saw blade 20A, 20B creates a saw slot in the workpiece to be machined.

[0033] FIG. 3 shows a machining tool designed as a removal disc 30. The removal disc 30 comprises several machining segments 31, a basic body 32 and a tool holder. The machining segments 31, which are used for removal, are also referred to as removal segments, and the disc-shaped base body 32 is also referred to as a cup. The removal segments 31 are firmly connected to the cup 32, for example by screwing, gluing, soldering, or welding.

[0034] The removal disc 30 is connected to a tool device via the tool holder and is rotated by the tool device in one direction of rotation during removal operation 34 around an axis of rotation 35driven. During the rotation of the removal disk 30 about the rotation axis 35, the removal disk 30 is moved over a workpiece to be machined, with the movement running perpendicular to the rotation axis 35. The removal disk 30 removes the surface of the workpiece to be machined.

[0035] FIG. 4 shows a cutting chain 40 trained processing tool. The cutting chain 40 comprises several processing segments 41, several limb-shaped basic bodies 42 and several connecting links 43. The machining segments 41, which are used for cutting-off grinding, are also referred to as cutting-off grinding segments and the link-shaped base bodies 42 are also referred to as drive links.

[0036] The drive links 42 are connected via connecting links 43. In the exemplary embodiment, the connecting links 43 are connected to the drive links 42 via rivet bolts. The rivet bolts enable rotation of the drive links 42 relative to the connecting links 43 about a rotation axis that runs through the center of the rivet bolts. The machining segments 41 are firmly connected to the drive links 42, for example, by screwing, gluing, soldering, or welding.

[0037] The cutting-off chain 40 is connected to a tool via a tool holder and, during operation, is driven by the tool in one direction of rotation. During rotation of the cutting-off chain 40, the cutting-off chain 40 is moved into a workpiece to be machined.

[0038] The production of a machining segment 51,which has hard material particles on its upper side with a projection relative to the matrix material, is carried out using the method according to the invention for producing a green compact and the method for further processing the green compact into a processing segment. In a first step, a green compact 52 manufactured, in a second stage the green body 52 is turned into a pressed body 53 compacted and in a third stage, the compact 53 is further processed into the processing segment 51. Alternatively, a green compact can be produced in a first stage, which is further processed into the processing segment in a second stage.

[0039] FIGN. 5A-C show the greenling 52 ( FIG. 5A ), the pellet 53 ( FIG. 5B ) and the processing segment 51 ( FIG. 5C ). The machining segment 51 consists of a machining zone 54 and a neutral zone 55The neutral zone 55 is required if the machining segment 51 is to be welded to the base body of a machining tool and the combination of matrix material and base body is not weldable; for weldable combinations of matrix material and base body, the neutral zone 55 can be omitted.

[0040] The processing zone 54 is made of a powder or granular first matrix material 56 and first hard material particles 57, which are arranged according to a defined first particle pattern, and the neutral zone 55 is made of a powder or granular second matrix material 59The term "matrix material" encompasses all materials used to construct machining segments into which hard material particles can be embedded. Matrix materials can consist of a single material or be composed of a mixture of different materials. The term "hard material particles" encompasses all cutting media for machining segments; these primarily include individual hard material particles, composite parts made up of multiple hard material particles, and coated or encapsulated hard material particles.

[0041] Machining segment 51 corresponds in structure and composition to machining segments 11A, 21A, 21B, 31, and 41; machining segment 11B, designed as a drill ring, differs from machining segment 51 in its annular structure. The machining segments can differ from one another in terms of dimensions and surface curvature. The structure of the machining segments is explained using machining segment 51 as an example and applies to machining segments 11A, 21A, 21B, 31, and 41.

[0042] The machining segment 51 comprises the first hard material particles 57 arranged in the first matrix material 56. The "first hard material particles" refer to the hard material particles of the machining segment 51 that machine a substrate, whereby the number of the first hard material particles 57 and the defined first particle pattern according to which the first hard material particles 57 are arranged in the first matrix material 56 are adapted to the requirements of the machining segment 51. The first hard material particles 57 generally originate from a particle distribution characterized by a minimum diameter, a maximum diameter, and an average diameter.

[0043] The processing segment 51 is provided with a bottom 61connected to the base body of the machining tool. In machining segments for core drilling and machining segments for removal, the underside of the machining segments is generally flat, whereas the underside of machining segments for sawing has a curve in order to be able to attach the machining segments to the curved end face of the ring- or disc-shaped base body. FIG. 5C In the machining segment 51 shown, the first hard material particles 57 have an upper side opposite the underside 61 62 a projection Δ relative to the first matrix material 56.

[0044] The green compact 52 is formed in a standing structure from the first matrix material 56, the first hard material particles 57, the second matrix material 59 and a powdered support material 63The support material 63 is different from the first matrix material 56 and serves to protect the first hard material particles 57 on the upper side 62.

[0045] The green body 52 is pressed between a first press die 64, which forms the bottom 61, and a second press die 65, which forms the upper side 62, is compacted. The pressing direction of the first pressing ram 64 and the second pressing ram 65 runs parallel to the construction direction of the green compact 52. Suitable methods for applying pressure to the green compact 52 include, for example, cold pressing methods or hot pressing methods. In cold pressing methods, the green compact 52 is exposed exclusively to pressure, whereas in hot pressing methods, the green compact 52 is exposed to temperatures up to approximately 200°C in addition to pressure.

[0046] The compact 53 is further processed into the processing segment 51 by free-form sintering or hot pressing. During free-form sintering, the compact 53 is subjected to temperature, while during hot pressing, it is subjected to pressure and temperature. If the compact 53 is further processed by free-form sintering, the green compact 52 is compacted until the compact 53 essentially has the final geometry of the processing segment 51. If the compact 53 is further processed by hot pressing, the compact 53 is further shaped during the hot pressing.

[0047] The properties of the support material 63, in particular the melting temperature T Schmelz , determine the behavior of the support material 63 during further processing. If the melting temperature T melt of the support material 63 is lower than the sintering temperature T Sinter of the first matrix material 76, the support material 63 changes its powdery or granular state upon heating and liquefies before the first matrix material 56 sinters; the liquid support material 63 can distribute itself throughout the first matrix material 76 during the sintering process and support the sintering process as an infiltrate. If the melting temperature T melt of the support material is higher than the sintering temperature T sinter of the first matrix material 56, the support material 63 remains in its powdery or granular state upon heating and can be easily removed from the finished machining segment after the sintering process.

[0048] FIGN. 6A-D show the production of the green compact 52 using the method according to the invention for producing a green compact. The green compact 52 is constructed from the first matrix material 56, the first hard material particles 57, the second matrix material 59, and the support material 63.

[0049] The production of the green body 52 takes place in several steps: In a first step, a support layer 66 of the support material 63 is applied ( FIG. 6A ), wherein the support material 63 can be applied in one layer or in several layers. In a second step, the first hard material particles 57 are arranged in the support material 63 according to the defined first particle pattern ( FIG. 6B ), wherein the first hard material particles 57 are not completely embedded in the support material 63, but have a projection relative to the support material 63. In a third step, a first matrix layer 67 of the first matrix material 56 is applied to the support material 63 and the first hard material particles 57 ( FIG. 6C ), wherein the first matrix material 56 can be applied in one layer or in several layers. In a fourth step, a second matrix layer 68of the second matrix material 59 is applied to the first matrix material 56 and the first hard material particles 57 ( FIG. 6D ), wherein the second matrix material 59 can be applied in one layer or in several layers. When producing a green compact for a machining segment without a neutral zone, the application of the second matrix material 59 can be omitted.

[0050] FIGN. 7A , B show another processing segment 71, which was produced using the method according to the invention for producing a green compact and the method for further processing the green compact into the processing segment. The processing segment 71 is produced in two stages: In a first stage, a green compact 72 manufactured ( FIG. 7A ) and in a second stage the green body 72 is further processed into the processing segment 71 ( FIG. 7B ).

[0051] The processing segment 71 differs from the processing segment 51 of the FIG. 5C in that the machining segment 71 consists of a machining zone 74 and has no neutral zone. The processing zone 74 is made of a powder or granular first matrix material 76, first hard material particles 77, which are arranged according to a defined first particle pattern, and second hard material particles 78 built.

[0052] Depending on the wear properties of the first matrix material 76, during machining of a substrate with the machining segment 71, friction with the substrate may lead to increased wear of the first matrix material 76 on the side surfaces of the machining segment 71. This wear can be reduced by the second hard material particles 78. FIG. 7B In the machining segment 71 shown, the second hard material particles 78 were arranged in the first matrix material 76 according to the defined second particle pattern. Alternatively, the second hard material particles 78 can be admixed to the first matrix material 76 as randomly distributed particles.

[0053] The first hard material particles 77 and second hard material particles 78 generally originate from particle distributions that are characterized by a minimum diameter, a maximum diameter, and an average diameter. In the exemplary embodiment of the FIGN. 7A , B, the first hard material particles 77 originate from a first particle distribution with a first average diameter, and the second hard material particles 78 originate from a second particle distribution with a second average diameter, wherein the first average diameter is greater than the second average diameter. Alternatively, the first hard material particles 77 and second hard material particles 78 can originate from the same particle distribution and have the same average diameter.

[0054] The machining segment 71 is provided with a bottom 81 connected to the base body of a machining tool. The machining of a substrate is carried out by first hard material particles 77, which are arranged on an upper side opposite the underside 81 82 are arranged.

[0055] The FIG. 7A The green compact 71 shown is made up of the first matrix material 76, the first hard material particles 77, the second hard material particles 83 and a powdered or granular support material 83 constructed. The support material 83 is different from the first matrix material 76 and serves to cover the first hard material particles 77 on the upper side 82. The state of the support material 83 is adapted to the state of the first matrix material 76, ie, with a powdery first matrix material 76, a powdery support material 83 is used, and with a granular first matrix material 76, a granular support material 83 is used.

[0056] The production of the green body 72 takes place in several steps: In a first step, the support material 83 is applied ( FIG. 6A ), wherein the support material 83 can be applied in one layer or in several layers. In a second step, the first hard material particles 77 are arranged in the support material 83 according to the defined first particle pattern ( FIG. 6B ), wherein the first hard material particles 77 are not completely embedded in the support material 83, but have a projection relative to the support material 83. The production of the green compact 72 ends with a sequence of a third and fourth step, wherein the sequence is carried out once or several times; in the case of the green compact 72 of the FIG. 7A The sequence of the third and fourth steps is performed three times. In the third step, the first matrix material 76 is applied, and in the fourth step, the second hard material particles 78 are arranged in the first matrix material 76 according to the defined second particle pattern.

[0057] The green compact 72 is further processed into the processing segment 71 by free-form sintering or hot pressing. Free-form sintering involves a temperature effect, while hot pressing involves pressure and temperature effects on the green compact 71. The properties of the support material 83, in particular the melting temperature T Schmelz , determine the behavior of the support material 83 during further processing. If the melting temperature T melt of the support material 83 is lower than the sintering temperature T Sinterof the first matrix material 76, the support material 83 changes its powdery or granular state upon heating and liquefies before the first matrix material 76 sinters; the liquid support material 83 can distribute itself throughout the first matrix material 76 during the sintering process and support the sintering process as an infiltrate. If the melting temperature T melt of the support material 83 is higher than the sintering temperature T sinter of the first matrix material 76, the support material 83 remains in its powdery or granular state upon heating and can be easily removed from the finished machining segment after the sintering process.

Claims

1. Method for producing a green body (52; 72) for a machining segment (11A, 11B; 21A, 21B; 31; 41; 51; 71) from a powdered or granular first matrix material (56; 76) and first hard material particles (57; 77), the machining segment being connected by an underside (61; 81) to a basic body (12A, 12B; 22A, 22B; 32; 42) of a machining tool (10A, 10B; 20A, 20B; 30; 40) and having a projection (Δ) of the first hard material particles (57; 77) on an upper side (62; 82) opposite from the underside (61; 81), characterized by the following steps: ▪ applying a powdered or granular supporting material (63; 83), the supporting material (63; 83) being different from the first matrix material (56; 76), ▪ arranging the first hard material particles (57; 77) in the supporting material (63; 83) according to a defined particle pattern, the first hard material particles (57; 77) being partially arranged in the supporting material (63; 83), and ▪ applying the first matrix material (56; 76) to the first hard material particles (57; 77) and the supporting material (63; 83).

2. Method according to Claim 1, characterized in that a supporting material (63; 83) with a melting temperature which is higher than the sintering temperature of the first matrix material (56; 76) is applied.

3. Method according to Claim 1, characterized in that a supporting material (63; 83) with a melting temperature which is lower than the sintering temperature of the first matrix material (56; 76) is applied.

4. Method for further processing the green body (52; 72) produced by the method for producing a green body according to one of Claims 1 to 3 to form a machining segment (51; 71).

5. Method according to Claim 4, characterized in that the green body (52) is compacted under the action of pressure to form a compact body (53) and the compact body (53) is then further processed to form the machining segment (51).

6. Method according to Claim 5, characterized in that the compact body (53) is further processed to form the machining segment (51) by free-form sintering or hot pressing.

7. Method according to Claim 4, characterized in that the green body (72) is further processed to form the machining segment (71) by free-form sintering or hot pressing.