METHOD FOR PRODUCING A MACHINING SEGMENT

Description

Technical area

[0001] The present invention relates to a method for producing a machining segment according to the preamble of claim 1. State of the art

[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 segments for core drill bits, saw blades, stock removal 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 according to the defined particle pattern. For machining segments that are welded to the base body of the machining tool, a structure consisting of a machining zone and a neutral zone has proven successful.The machining zone is constructed from a first matrix material and the neutral zone from a second matrix material which is different from the first matrix material.

[0004] 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 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 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.

[0005] WO 2017 / 011415 A1 discloses a method for producing a machining segment for a machining tool, which can be used to produce machining segments for machining concrete materials. The machining segment is connected to a base body of the machining tool via a bottom side and is constructed from a matrix material and hard material particles arranged according to a defined pattern.The method comprises the steps of: applying a support material; arranging the hard material particles according to the defined pattern in the support material; applying a first layer of the matrix material to the hard material particles and the support material and melting the first layer; carrying out a sequence of several steps which is carried out N times, N ≥ 1, wherein in a first step of the sequence a layer of the matrix material is applied to the layer structure and in a second step of the sequence the layer of the matrix material is melted and connected to the layer structure. Description of the invention

[0006] The object of the present invention is to develop an alternative 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.

[0007] 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.

[0008] The process for producing a machining segment comprises the following steps: ▪ Applying a powdered support material as a support layer, the melting temperature of the support material being greater than the melting temperature of the first matrix material, ▪ Arranging the first hard material particles according to the defined first particle pattern in the support material, the first hard material particles being arranged with a penetration depth in the support material, ▪ Applying a first layer of the first matrix material to the first hard material particles and the support material and melting the first layer using a powder bed fusion process and ▪ Carrying out a sequence of several steps which is carried out N times, N ≥ 1, wherein in a first step of the sequence a layer of the first matrix material is applied to the layer structure and in a second step of the sequence the layer of the first matrix material is melted and connected to the layer structure using the powder bed fusion process.

[0009] The method for producing a machining segment is characterized according to the invention in that the support material is powdered. The protrusion of the first hard material particles on the upper side of the machining segments is created using the support material, which is different from the first matrix material. The support material has a melting temperature that is higher than the melting temperature of the first matrix material. Because the melting temperature of the support material is higher than the melting temperature of the first matrix material, the support material remains powdered and can be easily removed from the finished machining segment. When the first matrix material melts, the support material remains in its powdered state and fixes the position of the first hard material particles.

[0010] After application, the first matrix material is melted and bonded to the layer structure. All known and future powder bed fusion processes using laser beams or electron beams are suitable for melting the first matrix material. The powder bed fusion process used is irrelevant for the method according to the invention for producing a machining segment. What is important is that the first matrix material is melted and bonded to the underlying layer structure.

[0011] The method according to the invention enables the production of machining segments that have first hard material particles with a protrusion on their upper surface and are therefore suitable for dry machining of concrete materials. The method according to the invention has the advantage that the finished machining segment can be removed at the end of the layer buildup, eliminating the need for further processing such as sintering or hot pressing.

[0012] In a first further development, the sequence comprises an intermediate step which is carried out between the first step and the second step of the sequence, wherein in the intermediate step second hard material particles are arranged in the layer of the first matrix material according to a defined second particle pattern. During machining with the machining segment, friction can lead to increased wear of the first matrix material on the side surfaces of the machining segment. This wear can be reduced by the second hard material particles. The arrangement of the second hard material particles according to the defined second particle pattern has the advantage over statistically distributed second hard material particles that the second hard material particles can be arranged in the side surfaces and can reduce wear on the side surfaces.

[0013] In an alternative development, second hard material particles are added to the first matrix material, with the average particle diameter of the second hard material particles being smaller than the average particle diameter of the first hard material particles. During machining with the machining segment, friction can lead to increased wear of the first matrix material on the side surfaces of the machining segment. This wear can be reduced by the second hard material particles.

[0014] Preferably, after the Nth sequence, at least one layer of a second matrix material is applied and melted using the powder bed fusion process and bonded to the layer structure, wherein the second matrix material is different from the first matrix material. The second matrix material enables the creation of a neutral zone. Neutral zones are used for machining segments when the machining segments are to be welded to the base body of a machining tool and the combination of first matrix material and base body is not weldable. The second matrix material is selected with a view to good weldability in combination with the base body.

[0015] Preferably, the first hard material particles have an average particle diameter and are embedded in the support material up to a maximum of half the average particle diameter. The protrusion of the first hard material particles on the upper side of the machining segments corresponds to the penetration depth with which the first hard material particles are embedded in the support material. Since the penetration depth of the first hard material particles is a maximum of 50% of the average particle diameter of the first hard material particles, it is ensured that the first hard material particles are securely fixed in the melted-out first matrix material in the finished machining segment. Examples of implementation

[0016] 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.

[0017] They show: FIGS. 1A, B show two variants of a machining tool designed as a core drill bit; FIGS. 2A, B show two variants of a machining tool designed as a saw blade; FIG. 3 shows a machining tool designed as a removal disk; FIG. 4 shows a machining tool designed as a cutting-off chain; FIGS. 5A-C show a green compact (FIG. 5A) which is compacted into a pressed compact (FIG. 5B) and further processed into a machining segment (FIG. 5C); FIGS. 6A-D show the production of the green compact of FIG. 5A using the method according to the invention for producing a green compact; FIGS. 7A, B show a green compact ( FIG. 7A ), which is further processed into a processing segment ( FIG. 7B ).

[0018] FIG. 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".

[0019] 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.

[0020] 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.

[0021] 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.

[0022] The drill shaft 12A, 12B is in the embodiment of the FIG. 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.

[0023] FIG. 2A , B show two variants of a saw blade 20A, 20BThe 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".

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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 processing 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.

[0030] 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.

[0031] 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. As the cutting-off chain 40 rotates, the cutting-off chain 40 is moved into the workpiece to be machined.

[0032] FIG. 5 shows a processing segment 51, which was produced by means of the method according to the invention for producing a machining segment. The machining segment 51 is composed of a machining zone 52 and a neutral zone 53 The neutral zone 53 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 53 can be omitted.

[0033] The processing zone 52 is made of a powder or granular first matrix material 54 and first hard material particles 55, which are arranged according to a defined first particle pattern, and the neutral zone 53 is made of a powder or granular second matrix material 56 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 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.

[0034] Machining segment 51 corresponds in structure and composition to machining segments 11A, 21A, 21B, 31, 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 their dimensions and surface curvatures. The structure of the machining segments is explained using machining segment 51 as an example and applies to machining segments 11A, 21A, 21B, 31, 41.

[0035] The processing segment 51 comprises the first hard material particles 55, which are arranged in the first matrix material 54. The hard material particles of the processing segment 51 that process a substrate are referred to as "first hard material particles," wherein the number of the first hard material particles 55 and the defined first particle pattern according to which the first hard material particles 55 are arranged in the first matrix material 54 are adapted to the requirements of the processing segment 51. The first hard material particles 55 generally originate from a particle distribution characterized by a minimum diameter, a maximum diameter, and an average diameter. d medium is characterized.

[0036] The processing segment 51 is provided with a bottom 58connected to the base body of the machining tool. In the case of 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. 5 In the machining segment 51 shown, the first hard material particles 55 have an upper side opposite the underside 58 59 a projection Δ relative to the first matrix material 54.

[0037] FIGS. 6A-Dshow the production of the machining segment 51 using the method according to the invention for producing a machining segment. The machining segment 51 is formed in a vertical configuration from top to bottom from the first matrix material 54, the first hard material particles 55, the second matrix material 56 and a powdered support material 61 The support material 61 is different from the first matrix material 54 and serves to support the first hard material particles 55 so that they can maintain their position according to the defined first particle pattern. The support material 61 has a melting temperature T Schmelz which is greater than the melting temperature T 1 of the first matrix material 54.

[0038] The production of the machining segment 51 takes place in several steps: In a first step, a support layer 62of the support material 61 and in a second step, the first hard material particles 55 are arranged in the support material 61 according to the defined first particle pattern, wherein the first hard material particles 55 are arranged with a projection δ in the support material 61 ( FIG. 6A ); the penetration depth d in of the first hard material particles 55 is a maximum of 50% of the average particle diameter d of the first hard material particles 55. Since the penetration depth d in the first hard material particles 55 is a maximum of 50% of the average particle diameter, it is ensured that the first hard material particles 55 are securely fastened in the first matrix material 54 in the finished machining segment 51.

[0039] In a third step, a first layer 63 of the first matrix material 54 is applied to the first hard material particles 55 and the support material 61 and melted by means of a powder bed fusion process ( FIG. 6B). The production of the processing segment 51 is continued with a sequence of steps, whereby the sequence can be carried out once or multiple times (N times with N ≥ 1); in the exemplary embodiment, the sequence is carried out once. In a first step of the sequence, a layer 64 of the first matrix material 54 is applied to the previous layer structure ( FIG. 6C ) and in a second step of the sequence, the layer 64 of the first matrix material 54 is melted by means of the powder bed fusion process.

[0040] Following the sequence, in a further step of the method according to the invention, a layer 65 the second matrix material 56 is applied to the previous layer structure and melted by means of the powder bed fusion process and thereby connected to the previous layer structure.

[0041] FIGS. 7A-F show another processing segment 71,which was produced using the method according to the invention for producing a machining segment. FIGS. 7A-E the intermediate products of processing segment 71 and FIG. 7F shows the finished machining segment 71.

[0042] The processing segment 71 differs from the processing segment 51 of the FIG. 5 in that the machining segment 71 only has one machining zone 72 and has no neutral zone. The processing zone 72 is made of a powder or granular first matrix material 74, first hard material particles 75, which are arranged according to a defined first particle pattern, and second hard material particles 76, which are arranged according to a defined second particle pattern.

[0043] During machining of a substrate with the machining segment 71, friction with the substrate can lead to increased wear of the first matrix material 74 on the side surfaces of the machining segment 71. This wear can be reduced by the second hard material particles 76. In the machining segment 71, the second hard material particles 76 were arranged in the first matrix material 74 according to the defined second particle pattern; alternatively, the second hard material particles 76 can be admixed to the first matrix material 74 as randomly distributed particles.

[0044] The first hard material particles 75 and second hard material particles 76 generally originate from particle distributions characterized by a minimum diameter, a maximum diameter, and an average diameter. In the machining segment 71, the first hard material particles 75 originate from a first particle distribution with a first average diameter. d medium,1 and the second hard material particles 76 of a second particle distribution with a second average diameter d medium,2 , wherein the first mean diameter is larger than the second mean diameter. Alternatively, the first hard material particles 75 and the second hard material particles 76 may originate from the same particle distribution and have the same mean diameter.

[0045] The processing segment 71 is provided with a bottom 78connected to the base body of a machining tool. The machining of a substrate is carried out by the first hard material particles 75, which are arranged on an upper side 79 opposite the underside 78. The machining segment 71 is formed in the upright configuration from top to bottom from the first matrix material 74, the first hard material particles 75, the second hard material particles 76 and a powdered support material 81 The support material 81 is different from the first matrix material 74 and serves to support the first hard material particles 75 so that they can maintain their position according to the defined first particle pattern. The support material 81 has a melting temperature T Schmelz which is greater than the melting temperature T 1 of the first matrix material 74.

[0046] The production of the machining segment 71 takes place in several steps: In a first step, a support layer 82of the support material 81 and in a second step, the first hard material particles 75 are arranged in the support material 81 according to the defined first particle pattern ( FIG. 7A ), wherein the first hard material particles 75 are not completely embedded in the support material 81, but have a projection δ relative to the support material 81; the penetration depth d in of the first hard material particles 75 is a maximum of 50% of the first average particle diameter d average,1 of the first hard material particles 75. In a third step, a first layer 83 of the first matrix material 74 is applied to the first hard material particles 75 and the support material 81 and melted by means of a powder bed fusion process ( FIG. 7B )

[0047] The production of the processing segment 71 is continued with a sequence of steps, whereby the sequence is carried out once or multiple times (N-fold with N ≥ 1); in the case of processing segment 71, the sequence is carried out twice. In a first step of the first sequence, a layer 84 of the first matrix material 74, in an intermediate step of the first sequence, the second hard material particles 76 are arranged in the layer 84 of the first matrix material 74 according to the defined second particle pattern ( FIG. 7C ) and in a second step of the first sequence, the layer 84 of the first matrix material 74 is melted by means of the powder bed fusion process and connected to the previous layer structure ( FIG. 7D ).

[0048] In a first step of the second sequence, another layer 85of the first matrix material 74, in an intermediate step of the second sequence, the second hard material particles 76 are arranged in the layer 85 of the first matrix material 74 according to the defined second particle pattern ( FIG. 7E ) and in a second step of the second sequence, the layer 85 of the first matrix material 74 is melted using the powder bed fusion process and bonded to the previous layer structure. After the second sequence, the processing segment 71 is finished and is removed from the support material 81 ( FIG. 7F ).

Claims

1. Method for producing a machining segment (11A, 11B; 21A, 21B; 31; 41; 51; 71) for a machining tool (10A, 10B; 20A, 20B; 30; 40) from a first powdered matrix material (54; 74) and first hard material particles (55; 75) which are arranged according to a defined first particle pattern, wherein the machining segment is connected by an underside (58; 78) to a basic body (12A, 12B; 22A, 22B; 32; 42) of the machining tool (10A, 10B; 20A, 20B; 30; 40), and the machining segment has, on an upper side (59; 79) opposite from the underside (58; 78), a projection of the first hard material particles (55; 75), comprising the steps of: ▪ applying a supporting material (61; 81) as a supporting layer (62; 82), wherein the melting temperature (Tmelt) of the supporting material (61; 81) is higher than the melting temperature (T1) of the first matrix material (54; 74), ▪ arranging the first hard material particles (55; 75) according to the defined first particle pattern in the supporting material (61; 81), wherein the first hard material particles (55; 75) are arranged with a depth of penetration (din) in the supporting material (61; 81), ▪ applying a first layer (63; 83) of the first matrix material (54; 74) to the first hard material particles (55; 75) and the supporting material (61; 81) and fusing the first layer (63; 83) by means of a powder bed fusion method, and ▪ performing a sequence of a plurality of steps, which is performed N times, N ≥ 1, wherein, in a first step of the sequence, a layer (64; 84, 85) of the first matrix material (54; 74) is applied to the layer structure, and in a second step of the sequence, the layer (64; 84, 85) of the first matrix material (54; 74) is fused by means of the powder bed fusion method and connected to the layer structure, characterized in that the supporting material (61; 81) is powdered.

2. Method according to Claim 1, wherein the sequence comprises an intermediate step which is performed between the first step and the second step of the sequence, wherein, in the intermediate step, second hard material particles (76) are arranged according to a defined second particle pattern in the layer (84, 85) of the first matrix material (74).

3. Method according to Claim 1, wherein second hard material particles (76) are admixed with the first matrix material (74), wherein an average particle diameter of the second hard material particles (76) is less than an average particle diameter of the first hard material particles (75).

4. Method according to one of Claims 1 to 3, wherein, after the N-th sequence, at least one layer (65) of a second powdered matrix material (56) is applied and fused by means of the powder bed fusion method and connected to the layer structure, wherein the second matrix material (56) is different from the first matrix material (54).

5. Method according to one of Claims 1 to 4, wherein the first hard material particles (55; 75) have an average particle diameter (dave, dave,1) and are embedded at most up to half the average particle diameter in the supporting material (61; 81).