METHOD FOR PRODUCEING A MACHINING SEGMENT FOR THE DRY MACHINING OF CONCRETE MATERIALS

Description

Technisches Gebiet

[0001] The present invention relates to a method for producing a machining segment according to claim 1. 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 removal are called stock removal segments; and machining segments used for cutting are called cutting segments.

[0003] Machining tools designed as core drill bits, saw blades, removal discs, or cutting-off chains, and intended for wet machining of concrete materials, 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 drilling slurry, and new hard material particles are exposed. During dry machining of concrete materials, no abrasive drilling slurry can form that can support the machining process. The hard material particles quickly become blunt, and the machining rate drops. Due to the lack of concrete slurry, the matrix material wears too slowly, and deeper-lying hard material particles cannot be exposed.In known wet machining tools, the matrix material and the hard material particles exhibit similar wear rates.

[0004] 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 set hard material particles, a green compact is built up layer by layer from matrix material, into which the hard material particles are placed at defined positions.

[0005] WO 2008 / 091039 A1 and WO 2008 / 091040 A1 disclose a known method for producing a machining 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 part under the influence of pressure between a first pressing die, which forms the underside of the machining segment, and a second pressing die, which forms an upper side of the machining segment opposite the underside. In a third step, the pressed part is further processed into the machining segment under the influence of temperature.

[0006] 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 projection. Darstellung der Erfindung

[0007] The object of the present invention is to develop a method for producing a machining segment that can be used to produce machining segments suitable for dry machining of concrete materials. The machining segment should exhibit a high machining rate and the longest possible service life during dry machining of concrete materials.

[0008] 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.

[0009] 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 by 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 greater than 400 µm, is characterized according to the invention in that a second press die is used during the compaction of the green compact, which has depressions in a pressing surface, wherein the arrangement of the depressions corresponds 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 machining segment with a projection of the first hard material particles relative to the first matrix material on the top side.The recesses, which correspond to the defined particle pattern of the first hard material particles, are necessary to create the protrusion of the first hard material particles on the upper side during hot pressing.

[0010] Machining segments produced using the method according to the invention are produced in a two-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, and in a second stage, the green compact is further processed into the machining segment by hot pressing under the influence of temperature and pressure between a first press die, which forms the underside of the machining segment, and a second press die, which forms an upper side of the machining segment opposite the underside.

[0011] The method according to the invention enables the production of machining 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. Machining 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 machining of concrete materials. The greater the projection of the first hard material particles, the higher the machining rate that can be achieved with the machining tool.

[0012] 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. Once the cover layer has completely embedded the first hard material particles, strong compaction with the second press die is required to create a protrusion of more than 400 µm of the first hard material particles above the first matrix material on the upper side.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 when the first hard material particles are completely embedded.

[0013] In a second preferred variant, after the first hard material particles have been placed, a cover layer of a second matrix material is applied, wherein the second matrix material is 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 upper side. 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 and easily.

[0014] 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, wherein the second matrix material is 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 punch. 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 and easily.

[0015] In a further development of the process, first hard material particles are used that are coated with a shell material, with the shell material corresponding 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, thus reducing wear on the second press die.

[0016] In an alternative development of the process, first hard material particles are used that 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 do not come into direct contact with the second press ram and wear on 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 pressing and should be able to be removed as quickly as possible once the processing segment is finished in order to expose the first hard material particles that process the concrete material. Ausführungsbeispiele

[0017] Embodiments of the invention are described below with reference to the drawing. These are not necessarily intended to represent the embodiments to scale; rather, where useful for explanation, the drawing is schematic and / or slightly distorted. It should be noted that numerous modifications and changes to the form and detail of an embodiment can be made without deviating 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 numerals are used below for identical or similar parts or parts with identical or similar functions.

[0018] 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 machining 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 FIGN. 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 compact; and FIGS. 7A-C some tool components used in the production of the machining segment of the FIGN. 5A-C be used.

[0019] FIGN. 1A , B show 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".

[0020] 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 drill segments, and the tubular base body 12A is also referred to as the drill shaft. The drill segments 11A are firmly connected to the drill shaft 12A, for example, by screwing, gluing, soldering, or welding.

[0021] 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.

[0022] 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 a rotational axis 15. During the rotation of the core drill bit 10A, 10B around the rotational 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 drilling crown 10A, 10B creates a drill core and a drill hole in the workpiece to be machined.

[0023] 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-rotate 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.

[0024] FIGN. 2A , B show two variants of a saw blade 20A, 20B The machining tool developed in 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".

[0025] 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.

[0026] 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.

[0027] 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.

[0028] FIG. 3 shows a removal disc 30designed machining tool. The removal disk 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.

[0029] 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 35 driven. 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.

[0030] FIG. 4 shows a cutting chain 36 trained processing tool. The cutting chain 36 comprises several processing segments 37, several limb-shaped basic bodies 38 and several connecting links 39. The processing segments 37, which are used for cutting, are also referred to as cutting segments and the link-shaped base bodies 38 are also referred to as drive links.

[0031] The drive links 38 are connected via 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 rotation of the drive links 38 relative to the connecting links 39 about a rotation axis that runs through the center of the rivet bolts. The machining segments 37 are firmly connected to the drive links 38, for example, by screwing, gluing, soldering, or welding.

[0032] The cutting-off chain 36 is connected to a tool via a tool holder and, during operation, is driven by the tool in one direction of rotation. As the cutting-off chain 36 rotates, the cutting-off chain 36 is moved into the workpiece to be machined.

[0033] FIGN. 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 ).

[0034] The machining segment 41 corresponds in structure and composition to the machining segments 11A, 21A, 21B, 31, 37; the machining segment 11B, designed as a drill ring, differs from the machining segment 41 in its annular structure. The machining segments can differ from one another in terms of dimensions and surface curvatures. 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 FIGN. 1A , B, for the machining segments 21A, 21B of the FIGN. 2A , B, for the processing segment 31 of the FIG. 3 and for the processing segment 37 of the FIG. 4 .

[0035] The machining segment 41 consists of a machining zone 42 and a neutral zone 43The 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 that are connected to the base body, for example, by soldering or gluing, the neutral zone 43 can be omitted. The machining zone 42 is made of a first matrix material 44 and first hard material particles 45 and the neutral zone 43 is made of a second matrix material 46 constructed without hard material particles.

[0036] The term "hard material particles" encompasses all cutting media for machining segments; this primarily includes individual hard material particles, composite parts made up of multiple hard material particles, and coated or encapsulated hard material particles. The 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.

[0037] Machining segments produced using the method according to the invention for producing a machining segment have a layer with first hard material particles 45; no further layers with first hard material particles 45 are provided. The "first hard material particles" refers to the hard material particles of the machining segment 41 that, after the machining segment has been produced, have a projection on the upper side relative to the first matrix material 44. Hard material particles that are completely embedded in the first matrix material 44 in the machining segment 41 do not fall under the definition of first hard material particles.

[0038] The processing segment 41 is provided with a bottom 47connected 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 to allow the machining segments to be attached to the curved end face of the ring- or disc-shaped base body.

[0039] The first hard material particles 45 are arranged according to a defined particle pattern in the first matrix material 44 ( FIG. 5B ) and have on a top side opposite the bottom 47 48 of the machining segment 41 a projection T 1 compared to the first matrix material 44. In the embodiment of the FIGN. 5A-C The machining 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 machining segment 41. The first hard material particles 45 generally originate from a particle distribution characterized by a minimum diameter, a maximum diameter, and an average diameter.

[0040] Due to the particle distribution of the first hard material particles 45 between the minimum and maximum diameter, the projections 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 projection of more than 400 µm relative to the surrounding first matrix material 44. The FIGN. 1A , B, FIGN. 2A , B, FIG. 3 und FIG. 4 The machining tools according to the invention shown, which are intended for machining concrete materials, have a defined direction of rotation. Viewed in the direction of rotation of the machining tool, a distinction can be made between a front-side region and a rear-side region of a hard material particle 45. Due to its geometry with a flat underside, the machining segment 41 is suitable as a drilling segment for the core drill bit 10A. The direction of rotation 14 of the core drill bit 10A defines a front-side region 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 projection of the first hard material particles in the front areas 51. The first hard material particles 45 have a front projection in the front area 51 T front and in the rear area a rear overhang T back 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.

[0041] The production of the machining segment 41 is carried out using the method according to the invention in two stages: In a first stage, a green body 53 and in a second stage the green body 53 is further processed into the processing segment 41. FIG. 6 shows the green compact 53 and the machining segment 41. The green compact 53 is constructed from the first matrix material 44 and the first hard material particles 45, in addition, a cover layer 55 of a matrix material. The first matrix material 44 or a second matrix material is suitable as the matrix material for the cover layer 56, which is different from the first matrix material 44.

[0042] FIGN. 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 matrix 62 and an upper stamp 63, where the lower punch 61 is also referred to as the first press punch and the upper punch 63 as the second press punch. FIGN. 7B und 7C show the upper stamp 63 in detail.

[0043] The green compact 53 is formed in the die 62 with a cross-sectional area corresponding 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 side into which the upper punch 63 can be moved. The upper punch 63 has depressions in the pressing surface. 64 whose arrangement corresponds to the defined particle pattern of the first hard material particles 45.

[0044] The green compact 53 is built from top to bottom. The first hard material particles 45, which protrude from the top side 48 of the processing segment 41 and process the concrete material, are placed in the recesses 64 of the lower punch 61. The first matrix material 44 is applied to the placed first hard material particles 45, whereby the first matrix material 44 can be applied in one or more layers. The first matrix material 44 is filled into the die 62 using a filling shoe until the desired fill level is reached.

[0045] The finished green compact 53 is processed into the processing segment 41 under the influence of temperature and pressure using the lower punch 61 and the upper punch 63. The green compact 53 is pressed using the special upper punch 63 in a pressing direction perpendicular to the cross-sectional area of ​​the green compact 53. The recesses 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 create the processing segments 41 that are suitable for dry processing of concrete materials. The recesses 64 are necessary to create the protrusion of the first hard material particles 45 on the upper side 48 during hot pressing.

[0046] Direct contact between the first hard material particles 45 and the recesses 64 of the upper punch 63 may result in increased wear of the upper punch 63. 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.

[0047] After the first hard material particles 45 have been placed, 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 different from the first matrix material 44. 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 during the pressing of the green compact 53 and should be able to be removed as quickly as possible after the finished machining segment in order to expose the first hard material particles 45 that machine the substrate. A second matrix material 56 with a higher wear rate than the first matrix material 44 can be removed quickly.

[0048] 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 wear on 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, wherein 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 once the processing segment is finished in order to expose the first hard material particles 45, which process the concrete material.

[0049] Depending on the wear characteristics of the first matrix material 44, increased wear of the first matrix material 44 on the side surfaces of the machining segment 41 may occur during machining of a substrate with the machining 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 randomly distributed particles, or the second hard material particles can be 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 region of the side surfaces of the machining segment 41.

Claims

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, and • the green body (53) is further processed by hot pressing under the action of temperature and 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 (53), to form the machining segment (41), wherein a second press punch (63), which has depressions (64) in a pressing surface, is used when hot pressing the green body (53), wherein the arrangement of the depressions (64) corresponds to the defined particle pattern of the first hard material particles (45).

2. The method as claimed in claim 1, wherein, after the placement of the first hard material particles (45), an outer layer (55) of the first matrix material (44) is applied.

3. The method as claimed in claim 1, wherein, 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. The method as claimed in claim 1, wherein, 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. The method as claimed in one of claims 1 to 4, wherein 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. The method as claimed in one of claims 1 to 4, wherein 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).