EP3898035B1 - Method for producing a processing segment for the dry processing of concrete materials - Google Patents

Description

technical field

The present invention relates to a method for producing a machining segment according to claim 1.

State of the art

Machining tools such as core drill bits, saw blades, removal disks and abrasive chains comprise machining segments that are attached to a tubular, disk or ring-shaped base body, whereby the machining segments are connected to the base body by welding, soldering or gluing. Depending on the machining method 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 removal are called removal segments and machining segments used for abrasive cutting are called abrasive cutting segments.

Processing tools designed as core drill bits, saw blades, removal disks or cutting-off chains and intended for wet processing of concrete materials are only suitable to a limited extent for dry processing of concrete materials. When processing concrete materials wet, an abrasive concrete slurry is created that supports the processing process and leads to the processing segments sharpening themselves during processing. The matrix material is removed by the abrasive drilling slurry and new hard material particles are exposed. When processing concrete materials dry, no abrasive drilling slurry can form that can support the processing process. The hard material particles quickly become blunt and the processing rate drops. Due to the lack of concrete slurry, the matrix material wears too slowly and deeper hard material particles cannot be exposed. In known processing tools for wet processing, the matrix material and the hard material particles have similar wear rates.

Processing segments for core drill bits, saw blades, removal discs and abrasive chains are made from a matrix material and hard material particles, whereby the hard material particles can be randomly distributed or arranged in the matrix material according to a defined particle pattern. For processing segments with randomly distributed hard material particles, the matrix material and the hard material particles are mixed, the mixture is filled into a suitable tool mold and further processed to form the processing segment. For processing segments with set hard material particles, a green part is built up layer by layer from matrix material, in which the hard material particles are placed at defined positions.

WO 2008/091039 A1 and WO 2008/091040 A1 disclose a known method for producing a processing segment. In a first step, a green compact is constructed from a matrix material and hard material particles, with the hard material particles being placed in the matrix material according to a defined particle pattern. In a second step, the green compact is compacted into a pressed compact under the influence of pressure between a first press die, which forms the underside of the processing segment, and a second press die, which forms an upper side of the processing segment opposite the underside. In a third step, the pressed compact is further processed into the processing segment under the influence of temperature.

US 6,045,750 A discloses known methods for producing a green compact for a machining segment. The green compact is constructed from a matrix material and hard material particles and the hard material particles are placed in the first matrix material on an upper side of the green compact opposite the underside.

The known method for producing a machining segment has the disadvantage that the hard material particles on the upper side of the finished machining segment do not have any protrusion.

representation of the invention

The object of the present invention is to develop a method for producing a processing segment with which processing segments can be produced that are suitable for the dry processing of concrete materials. The processing segment should have a high processing rate and the longest possible service life when dry processing concrete materials.

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.

The method for producing a machining segment from a first matrix material and first hard material particles for a machining tool, wherein the machining segment is connected with a bottom side to a base body of the machining tool and the projection of at least one first hard material particle relative to the first Matrix material is larger than 400 µm, is characterized according to the invention in that when compacting the green compact, the second press die is used, which has depressions in a pressing surface, the arrangement of the depressions corresponding to the defined particle pattern of the first hard material particles. By using a second press die, which has an arrangement of depressions for the first hard material particles in the pressing surface, the green compact can be compacted into a compact with a projection of the first hard material particles relative to the first matrix material on the upper side. The depressions, which correspond to the defined particle pattern of the first hard material particles, are necessary in order to produce the projection of the first hard material particles on the upper side during pressing.

Processing segments that are produced using the method according to the invention are produced in a three-stage process: In a first stage, a green compact is constructed from the first matrix material and the first hard material particles, wherein the first hard material particles are placed in the first matrix material according to a defined particle pattern; in a second stage, the green compact is compacted into a pressed compact under the influence of pressure between a first press die that forms the underside of the processing segment and a second press die that forms an upper side of the processing segment opposite the underside; and in a third stage, the pressed compact is further processed into the processing segment under the influence of temperature or by infiltration.

The method according to the invention enables the production of processing segments with a projection of the first hard material particles relative to the first matrix material, wherein the projection of at least one first hard material particle relative to the first matrix material is greater than 400 µm. Processing segments in which at least one of the first hard material particles has a projection of more than 400 µm relative to the first matrix material are suitable for the dry processing of concrete materials. The greater the projection of the first hard material particles, the higher the processing rate that can be achieved with the processing tool.

In a first preferred variant, a cover layer of the first matrix material is applied after the first hard material particles have been placed. By applying the cover layer of the first matrix material, the first hard material particles can be embedded sufficiently deeply in the first matrix material to ensure that the first hard material particles are sufficiently secured in the finished machining segment and that the first hard material particles do not break out. The height of the cover layer of the first matrix material is adapted to the requirements. When the cover layer completely covers the first hard material particles embeds, a strong compaction with the second press die is required in order to create a protrusion of more than 400 µm of the first hard material particles on the top side compared to the first matrix material. If the cover layer does not completely embed the first hard material particles, the green body already has a protrusion of the first hard material particles compared to the first matrix material, but the wear of the second press die is greater than with fully embedded first hard material particles.

In a second preferred variant, after the first hard material particles have been placed, a cover layer of a second matrix material is applied, the second matrix material being different from the first matrix material. Applying a cover layer of a second matrix material that is different from the first matrix material offers the possibility of using matrix materials with different wear properties. If the cover layer completely embeds the first hard material particles, the finished machining segment has a protective layer on the top. This protective layer is removed by sharpening the machining segments or during machining. In both cases, it is advantageous to use a second matrix material with a high wear rate so that the first hard material particles can be exposed quickly or easily.

In a third preferred variant, after the first hard material particles have been placed, a first cover layer of the first matrix material and a second cover layer of a second matrix material are applied, the second matrix material being different from the first matrix material. The first cover layer of the first matrix material ensures that the first hard material particles are embedded sufficiently deeply in the first matrix material, and the second cover layer of the second matrix material can serve as a protective layer for the second press die. This protective layer is removed by sharpening the machining segments or during machining. In both cases, it is advantageous to use a second matrix material with a high wear rate so that the first hard material particles can be exposed quickly or easily.

In a further development of the process, first hard material particles are used which are coated by a shell material, whereby the shell material corresponds to the first matrix material. The use of coated first hard material particles has the advantage that the first hard material particles do not come into direct contact with the second press die and the wear of the second press die can be reduced.

In an alternative development of the process, first hard material particles are used which are coated by a shell material, whereby the shell material is different from the first matrix material. The use of coated first hard material particles has the advantage that the first hard material particles are not in direct contact with the second press die. and the wear of the second press ram can be reduced. When using a shell material that is different from the first matrix material, matrix materials with different wear properties can be used. The shell material serves to protect the second press ram during compaction and should be able to be removed as quickly as possible when the processing segment is finished in order to expose the first hard material particles that process the concrete material.

implementation examples

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

FIGN. 1A, B

zwei Varianten eines als Kernbohrkrone ausgebildeten Bearbeitungswerkzeuges;

FIGN. 2A, B

zwei Varianten eines als Sägeblatt ausgebildeten Bearbeitungswerkzeuges;

FIG. 3

ein als Abtragscheibe ausgebildetes Bearbeitungswerkzeug;

FIG. 4

ein als Trennschleifkette ausgebildetes Bearbeitungswerkzeug;

FIGN. 5A-C

ein Bearbeitungssegment in einer dreidimensionalen Darstellung (FIG. 5A), in einer Ansicht auf eine Oberseite (FIG. 5B) und in einer Ansicht auf einer Seitenfläche (FIG. 5C);

FIG. 6

die Herstellung des Bearbeitungssegmentes der FIGN. 5A-C gemäß dem erfindungsgemäßen Verfahren, wobei in einer ersten Stufe ein Grünling hergestellt wird und in einer zweiten Stufe der Grünling zu einem Pressling verdichtet wird; und

FIGN. 7A-C

einige Werkzeugkomponenten, die bei der Herstellung des Bearbeitungssegmentes der FIGN. 5A-C eingesetzt werden.

They show:

FIGS. 1A, B

two variants of a machining tool designed as a core drilling crown;

FIGS. 2A, B

two variants of a processing tool designed as a saw blade;

FIG. 3

a machining tool designed as a removal disc;

FIG. 4

a processing tool designed as a cutting-off chain;

FIGS. 5A-C

a processing segment in a three-dimensional representation ( FIG. 5A ), in a view of a top side ( FIG. 5B ) and in a view on a side surface ( FIG. 5C );

FIG. 6

the production of the machining segment of the FIGS. 5A-C according to the method according to the invention, wherein in a first stage a green compact is produced and in a second stage the green compact is compacted into a pressed compact; and

FIGS. 7A-C

some tool components used in the manufacture of the machining segment of the FIGS. 5A-C be used.

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

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, which are used for core drilling, are also referred to as drilling segments and the tubular base body 12A is also referred to as the drilling shaft. The drilling segments 11A are firmly connected to the drilling shaft 12A, for example by screwing, gluing, soldering or welding.

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 a drilling ring and the tubular base body 12B is also referred to as a drilling shaft. The drilling ring 11B is firmly connected to the drilling shaft 12B, for example by screwing, gluing, soldering or welding.

The core drill bit 10A, 10B is connected to a core drilling machine via the tool holder 13A, 13B and is driven by the core drilling machine in a direction of rotation 14 about a rotation axis 15 during drilling. While the core drill bit 10A, 10B rotates about the rotation axis 15, the core drill bit 10A, 10B is moved along a feed direction 16 into a workpiece to be machined, with the feed direction 16 running parallel to the rotation axis 15. The core drill bit 10A, 10B creates a drill core and a drill hole in the workpiece to be machined.

The drill shaft 12A, 12B is in the embodiment of the FIG. 1A , B are formed in one piece and the drilling segments 11A or the drilling ring 11B are firmly connected to the drilling shaft 12A, 12B. Alternatively, the drilling shaft 12A, 12B can be formed in two parts from a first drilling shaft section and a second drilling shaft section, wherein the drilling segments 11A or the drilling ring 11B are firmly connected to the first drilling shaft section and the tool holder 13A, 13B is firmly connected to the second drilling shaft section. The first and second drilling shaft sections are connected to one another via a detachable connection device. The detachable connection device is, for example, a plug-and-turn connection, as 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.

FIG. 2A , B show two variants of a processing tool designed as a saw blade 20A, 20B . The FIG. 2A The saw blade 20A shown is referred to as the first saw blade and the one 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 also referred to as the "saw blade".

The first saw blade 20A comprises several processing segments 21A, a disk-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 disk-shaped base body 22A is also referred to as the main blade. The saw segments 21A are firmly connected to the main blade 22A, for example by screwing, gluing, soldering or welding.

The second saw blade 20B comprises several processing segments 21B, a ring-shaped base body 22B and a tool holder. The processing 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.

The saw blade 20A, 20B is connected to a saw via the tool holder and is driven by the saw in a direction of rotation 24 about a rotation axis 25 during sawing operation. 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, with the feed direction running 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.

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

The removal disk 30 is connected to a tool device via the tool holder and, during removal operation, is rotated by the tool device in a direction of rotation 34 about a rotation axis 35. 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, the movement being perpendicular to the rotation axis 35. The removal disk 30 removes the surface of the workpiece to be machined.

FIG. 4 shows a processing tool designed as a cutting-off chain 36. The cutting-off chain 36 comprises several processing segments 37, several link-shaped base bodies 38 and several connecting links 39. The processing segments 37, which are used for cutting-off, are also referred to as cutting-off segments and the link-shaped base bodies 38 are also referred to as drive links.

The drive links 38 are connected via the connecting links 39. In the exemplary embodiment, the connecting links 39 are connected to the drive links 38 via rivet bolts. The rivet bolts enable the drive links 38 to rotate relative to the connecting links 39 about an axis of rotation that runs through the center of the rivet bolts. The processing segments 37 are firmly connected to the drive links 38, for example by screwing, gluing, soldering or welding.

The cutting-off chain 36 is connected to a tool device via a tool holder and is driven by the tool device in one direction of rotation during operation. During the rotation of the cutting-off chain 36, the cutting-off chain 36 is moved into a workpiece to be machined.

FIGS. 5A-C show a processing segment 41 in a three-dimensional representation ( FIG. 5A ), in a view of a top side of the machining segment 41 ( FIG. 5B ) and in a view of a side surface of the machining segment 41 ( FIG. 5C ).

The machining segment 41 corresponds in terms of structure and composition to the machining segments 11A, 21A, 21B, 31, 37; the machining segment 11B, which is designed as a drill ring, differs from the machining segment 41 in its ring-shaped structure. The machining segments can differ from one another in terms of the dimensions and the curvature of the surfaces. The basic structure of the machining segments according to the invention is explained using the machining segment 41 and applies to the machining segments 11A, 11B of the FIG. 1A , B, for the machining segments 21A, 21B of the FIG. 2A , B, for the processing segment 31 of the FIG. 3 and for the processing segment 37 of the FIG. 4 .

The machining segment 41 is made up of a machining zone 42 and a neutral zone 43. The neutral zone 43 is required if the machining segment 41 is to be connected to the base body of a machining tool; for machining segments, which are connected to the base body, for example, by soldering or gluing, the neutral zone 43 can be omitted. The processing zone 42 is made up of a first matrix material 44 and first hard material particles 45 and the neutral zone 43 is made up of a second matrix material 46 without hard material particles.

The term "hard material particles" covers all cutting media for machining segments; these include, in particular, individual hard material particles, composite parts made of several hard material particles and coated or encapsulated hard material particles. The term "matrix material" covers all materials used to construct machining segments in which hard material particles can be embedded. Matrix materials can consist of one material or be composed of a mixture of different materials.

Processing segments that are produced using the method according to the invention for producing a processing segment have a layer with first hard material particles 45; further layers with first hard material particles 45 are not provided. The term "first hard material particles" refers to the hard material particles of the processing segment 41 that have a projection on the top side relative to the first matrix material 44 after the processing segment has been produced. Hard material particles that are completely embedded in the first matrix material 44 in the processing segment 41 do not fall under the definition of the first hard material particles.

The machining segment 41 is connected to the base body of the machining tool by means of a lower side 47. In the case of machining segments for core drilling and machining segments for removal, the lower side of the machining segments is generally flat, whereas the lower side 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 disk-shaped base body.

The first hard material particles 45 are arranged according to a defined particle pattern in the first matrix material 44 ( FIG. 5B ) and have a projection T ₁ relative to the first matrix material 44 on an upper side 48 of the processing segment 41 opposite the lower side 47. In the embodiment of the FIGS. 5A-C the processing segment 41 comprises a number of 9 first hard material particles 45 that protrude on the upper side 48. The number of first hard material particles 45 and the defined particle pattern in which the first hard material particles 45 are arranged in the first matrix material 44 are adapted to the requirements of the processing segment 41. The first hard material particles 45 generally come from a particle distribution that is characterized by a minimum diameter, a maximum diameter and an average diameter. Due to the particle distribution of the first hard material particles 45 between the minimum and maximum diameter, the protrusions of the first hard material particles 45 can vary accordingly. In the example according to the invention, all first hard material particles 45 have a protrusion of more than 400 µm compared to the surrounding first matrix material 44. The FIG. 1A , B, FIG. 2A , B, FIG. 3 and FIG. 4 The processing tools according to the invention shown, which are intended for processing concrete materials, have a defined direction of rotation. Viewed in the direction of rotation of the processing tool, a distinction can be made between a front area and a rear area of a hard material particle 45. The processing segment 41 is suitable as a drilling segment for the core drill bit 10A due to its geometry with a flat underside. The direction of rotation 14 of the core drill bit 10A defines a front area 51 and a rear area 52. The processing of concrete materials takes place in the front areas 51 of the first hard material particles 45 and the processing rate depends essentially on the size of the protrusion of the first hard material particles in the front areas 51. The first hard material particles 45 have a front protrusion T _front in the front area 51 and a rear protrusion T _back in the rear area, which correspond in the exemplary embodiment. Alternatively, the first hard material particles 45 can have different front projections T _front and rear projections T _back .

The production of the processing segment 41 takes place using the method according to the invention in three stages: In a first stage, a green compact 53 is produced, in a second stage, the green compact 53 is compacted into a pressed compact 54 and in a third stage, the pressed compact 54 is further processed into the processing segment 41. FIG. 6 shows the green compact 53 and the pressed compact 54. The green compact 53 is constructed from the first matrix material 44 and the first hard material particles 45, and a cover layer 55 of a matrix material is additionally applied. The first matrix material 44 or a second matrix material 56, which is different from the first matrix material 44, is suitable as the matrix material for the cover layer.

The green compact 53 is compressed under pressure until the compact 54 essentially has the final geometry of the processing segment 41. Suitable methods for applying pressure to the green compact 53 include cold pressing methods or hot pressing methods. In cold pressing methods, the green compact 53 is only exposed to pressure, while in hot pressing methods, in addition to pressure, the green compact 53 is exposed to temperatures of up to approximately 200 °C. The compact 54 is further processed under the influence of temperature, for example during sintering or by infiltration, to form the processing segment 41.

FIGS. 7A-C show some tool components that are used in the production of the machining segment 41 using the method according to the invention. The tool components include a lower punch 61, a die 62 and an upper punch 63, wherein the lower punch 61 is also referred to as the first press punch and the upper punch 63 is referred to as the second press punch. FIGS. 7B and 7C show the upper stamp 63 in detail.

The green compact 53 is constructed in the die 62 with a cross-sectional area that corresponds to the desired geometry of the green compact 53. The die 62 has a first opening on the underside into which the lower punch 61 can be moved, and a second opening on the top into which the upper punch 63 can be moved. The upper punch 63 has depressions 64 in the pressing surface, the arrangement of which corresponds to the defined particle pattern of the first hard material particles 45.

The green compact 53 is built up from bottom to top. The first matrix material 44 is filled into the die 62 using a filling shoe until the desired filling level is reached. The first hard material particles 45 are placed in the surface of the first matrix material 44 in accordance with the defined particle pattern and embedded in the first matrix material 44 up to a desired embedding depth. The finished green compact 53 is compacted into the pressed compact 54 using the lower punch 61 and the upper punch 63. The green compact 53 is compacted into the pressed compact 54 using the special upper punch 63 in a pressing direction perpendicular to the cross-sectional area of the green compact 53. The depressions 64 in the pressing surface of the upper punch 63 have an arrangement that corresponds to the defined particle pattern of the first hard material particles 45. The special upper punch 63 can be used to produce the processing segments 41 that are suitable for dry processing of concrete materials. The recesses 64 are required to produce the protrusion of the first hard material particles 45 on the upper side 48 during pressing.

Direct contact between the first hard material particles 45 and the recesses 64 of the upper punch 63 can lead to increased wear of the upper punch 63. In order to reduce wear of the upper punch 63, direct contact of the first hard material particles 45 with the upper punch 63 should be avoided. Suitable measures include applying a matrix material as a cover layer and/or using coated first hard material particles 45.

After placing the first hard material particles 45, a cover layer 55 of the first matrix material 45 can be applied. Alternatively, a cover layer 55 of the second matrix material 56 can be applied, wherein the second matrix material 56 is separated from the first matrix material 44 is different. When using a second matrix material 56 that is different from the first matrix material 44, matrix materials with different wear properties can be used. The second matrix material 56 serves to protect the upper punch 63 when compacting the green compact 53 and should be able to be removed as quickly as possible when the machining segment is finished in order to expose the first hard material particles 45 that process the substrate. A second matrix material 56 with a higher wear rate than the first matrix material 44 can be removed quickly.

The use of coated first hard material particles has the advantage that the first hard material particles 45 do not come into direct contact with the upper punch 63 and the wear of the upper punch 63 can be reduced. The first matrix material 44 can be used as the coating material for the first hard material particles 45. Alternatively, a second matrix material can be used as the coating material for the first hard material particles 45, whereby the second matrix material is different from the first matrix material 44. When using a coating material that is different from the first matrix material 44, matrix materials with different wear properties can be used. The coating material serves to protect the upper punch 63 during compaction and should be able to be removed as quickly as possible when the processing segment is finished in order to expose the first hard material particles 45 that process the concrete material.

Depending on the wear properties of the first matrix material 44, increased wear of the first matrix material 44 on the side surfaces of the processing segment 41 can occur during processing of a substrate with the processing segment 41 due to friction with the substrate. This wear can be reduced by second hard material particles. The second hard material particles can be mixed into the first matrix material 44 as statistically distributed particles or the second hard material particles are placed in the first matrix material 44 according to a defined second particle pattern. The second hard material particles are placed in particular in the area of the side surfaces of the processing segment 41.

Claims (6)

1. Method for producing a machining segment (11A, 11B; 21A, 21B; 31; 37; 41) from a first matrix material (44) and first hard material particles (45) for a machining tool (10A, 10B; 20A, 20B; 30; 36), wherein the machining segment is connected by an underside (47) to a basic body (12A, 12B; 22A, 22B; 32; 38) of the machining tool (10A, 10B; 20A, 20B; 30; 36) and the projection (T1) at least of a first hard material particle with respect to the first matrix material is greater than 400 µm, with the following steps:

   • a green body (53) is built up from the first matrix material (44) and the first hard material particles (45), wherein the first hard material particles (45) are placed in the first matrix material (45) according to a defined particle pattern,

   • the green body (53) is compacted under the action of pressure between a first press punch (61), which forms the underside (47) of the machining segment, and a second press punch (63), which forms an upper side (48) of the machining segment opposite from the underside (47), in a pressing direction perpendicular to the cross-sectional area of the green body, to form a compact body (54) and

   • the compact body (54) is further processed under the action of temperature or by infiltration to form the machining segment (41),

   characterized in that a second press punch (63), which has depressions (64) in a pressing surface, is used when compacting the green body (53), the arrangement of the depressions (64) corresponding to the defined particle pattern of the first hard material particles (45).
2. Method according to Claim 1, characterized in that, after the placement of the first hard material particles (45), an outer layer (55) of the first matrix material (44) is applied.
3. Method according to Claim 1, characterized in that, after the placement of the first hard material particles (45), an outer layer (55) of a second matrix material (56) is applied, wherein the second matrix material (56) is different from the first matrix material (44).
4. Method according to Claim 1, characterized in that, after the placement of the first hard material particles (45), a first outer layer of the first matrix material (44) and a second outer layer of a second matrix material (56) are applied, wherein the second matrix material (56) is different from the first matrix material (44).
5. Method according to one of Claims 1 to 4, characterized in that first hard material particles (45) which are encased by a casing material are used, wherein the casing material corresponds to the first matrix material (44).
6. Method according to one of Claims 1 to 4, characterized in that first hard material particles (45) which are encased by a casing material are used, wherein the casing material is different from the first matrix material (44).

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