Cutting tool with asymmetrical teeth with cutting particles

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates to a cutting tool comprising a tooth with a tooth tip coated with cutting particles to form a plurality of geometrically undefined cutting edges. The cutting tool is a saw band or saw blade.

[0002] In contrast to saw blades with geometrically defined cutting edges, such cutting tools with geometrically indeterminate cutting edges are often not used for cutting or sawing metal, but rather other materials - such as glass, graphite, hard coal, ceramics, silicon, concrete materials, CFRP, sintered materials and natural stone. STATE OF THE ART

[0003] A grinding cutting tool with a tooth having a tooth tip coated with cutting particles to form a plurality of geometrically undefined cutting edges is known from German patent DE 697 00 910 T2. The tooth tip has a longitudinal central axis, a plateau surface, a first connecting surface, and a second connecting surface. The first connecting surface and the second connecting surface are directly adjacent to the plateau surface. Fig. 8 In the illustrated embodiment, the tooth tip is asymmetrical. DE 69700910 T2 discloses a cutting tool according to the preamble of claim 1.

[0004] A cutting tool with integrated lubricant is known from the German patent application DE 10 2010 062 073 A1.

[0005] A method for producing a grinding tool is known from European patent application EP 0 569 770 A1.

[0006] A cutting tool for cutting two different materials is known from the US patent application US 2017 / 0189977 A1.

[0007] A cutting tool with a tooth having a tooth tip coated with cutting particles to form a plurality of geometrically undefined cutting edges is known as a saw blade bearing the applicant's trademark "DIAGRIT," for example, from the applicant's catalog "PRECISION SAW BANDS," edition 2017, page 41. The tooth tip has a longitudinal center axis, a plateau surface, a first connecting surface, and a second connecting surface. The first connecting surface and the second connecting surface directly adjoin the plateau surface. Both connecting surfaces extend on their respective sides of the longitudinal center axis at the same absolute tooth tip angle to the plateau surface. The tooth tip angle is approximately 0°, i.e., the connecting surface runs approximately parallel to the longitudinal center axis of the tooth tip.

[0008] Further prior art is known from the documents WO 2008 / 119299 A1, US 2003 / 209125 A1, CN 106 625 304 A, DD 293 300 A5, KR 200 164 555 Y1, EP 1 663 579 A1 and DE 697 00 910 T2. OBJECT OF THE INVENTION

[0009] The invention is based on the object of providing a cutting tool designed as a saw band or saw blade with which workpieces made of different materials can be machined efficiently. SOLUTION

[0010] The object of the invention is achieved according to the invention with the features of the independent patent claims.

[0011] Further preferred embodiments of the invention can be found in the dependent patent claims. DESCRIPTION OF THE INVENTION

[0012] The invention relates to a cutting tool designed as a band saw or saw blade, comprising a tooth with a tooth tip coated with cutting particles to form a plurality of geometrically undefined cutting edges. The tooth tip is asymmetrically formed.

[0013] The invention further relates to a method for machining two workpieces made of different materials using precisely one cutting tool with a tooth having an asymmetrically shaped tooth tip coated with cutting particles to form a plurality of geometrically undefined cutting edges. The cutting tool is inserted in a first orientation into a cutting machine with a motor. A first workpiece made of a first material is then machined using the cutting tool in the first orientation by driving the cutting tool in a first direction of movement.

[0014] Thereafter, according to a first alternative a, the motor for driving the cutting tool is switched in an opposite second direction of movement and then a second workpiece made of a different second material is machined with the cutting tool in the first orientation.

[0015] According to a second alternative b, the cutting tool is instead removed from the cutting machine and inserted into the cutting machine in an opposite second orientation. A second workpiece made of a different second material is then machined with the cutting tool in the second orientation by driving the cutting tool in the first direction of movement. Definitions

[0016] The characteristic of the asymmetrical design of the tooth tip is to be understood as meaning that the tooth tip is asymmetrical in its basic geometry without taking the cutting particles into account. The tooth tip is asymmetrical in a main extension plane of the cutting tool. The main extension plane of the cutting tool corresponds, for example, to the drawing plane of the Fig. 2 and 5 The direction of movement of the cutting tool and the height of the tooth lie in the main plane of extension. The main plane of extension also contains a longitudinal center axis of the tooth tip, which, in the case of a band-shaped base body, extends perpendicular to the direction of movement of the cutting tool.

[0017] The asymmetrical tooth tip is thus designed in such a way that it is designed differently on a first side of the longitudinal center axis than on an opposite second side of the longitudinal center axis.

[0018] In other words, the tooth tip is designed asymmetrically in a side view in the direction of movement of the cutting tool such that the amount of the angle of the first surface of the tooth tip, which first comes into contact with the workpiece during cutting in a first direction of movement of the cutting tool, is not equal to the amount of the angle of the second surface of the tooth tip, which first comes into contact with the workpiece during cutting in an opposite second direction of movement of the cutting tool.

[0019] The tooth tip has a longitudinal central axis, a plateau surface, a first connecting surface, and a second connecting surface. The first connecting surface and the second connecting surface adjoin the plateau surface directly or indirectly. The first connecting surface runs on a first side of the longitudinal central axis at a first tooth tip angle with a first value to the plateau surface. The second connecting surface runs on an opposite second side of the longitudinal central axis at a second tooth tip angle with a different second value to the plateau surface. The tooth tip angles differ in magnitude, which gives the tooth tip an asymmetrical shape.

[0020] The preceding connection surface, viewed in the direction of movement of the cutting tool, corresponds in terms of its arrangement to the rake face of the tooth tip of a saw blade. The subsequent connection surface, viewed in the direction of movement of the cutting tool, corresponds in terms of its arrangement to the flank face of the tooth tip of a saw blade. If the direction of movement or the orientation of the cutting tool is reversed, the functionality of the connection surfaces is also reversed accordingly.

[0021] The tooth point angle of the preceding connection surface, as seen in the direction of movement of the cutting tool, corresponds in terms of its arrangement to the rake angle of the tooth tip of a saw blade. The tooth point angle of the subsequent connection surface, as seen in the direction of movement of the cutting tool, corresponds in terms of its arrangement to the clearance angle of the tooth tip of a saw blade. If the direction of movement or the orientation of the cutting tool is reversed, the functionality of the tooth point angles is also reversed accordingly.

[0022] With a negative tooth tip angle, the connecting surface of the tooth tip leading in the direction of movement of the cutting tool is inclined backward. With a positive tooth tip angle, the connecting surface of the tooth tip following in the direction of movement of the cutting tool is inclined forward. A positive tooth tip angle is more aggressive in terms of its cutting behavior than a negative tooth tip angle. For clarification, Fig. 8 in which the first connection surface 8 runs at a negative tooth tip angle.

[0023] The manufacturing process performed with the cutting tool is referred to as machining according to DIN 8589-0. According to this standard, a distinction is made between machining with geometrically defined cutting edges and machining with geometrically indeterminate cutting edges. Machining with geometrically defined cutting edges also includes sawing according to DIN 8589-6. The cutting tool in question uses geometrically indeterminate cutting edges, meaning that it is not a sawing tool according to the aforementioned standards. For this reason, the appropriate generalized term "cutting tool" is used in this application. In practice, cutting tools from this technical field with cutting particles are also referred to as saw bands or saw blades.

[0024] In this application, cutting particles are understood to be particles that effect the machining of the workpiece. They consist of or comprise a cutting material. A cutting material is a material suitable for cutting and machining workpieces. The cutting particles are therefore also cutting material particles.

[0025] In this application, buffer particles are understood to be particles that, through their presence and arrangement, create distances between the cutting particles and thus form a buffer between the cutting particles. The buffer particles do not ultimately cause the machining of the workpiece and are therefore not cutting particles. The buffer particles can consist of different materials. However, it is also possible for the buffer particles to consist of or contain a cutting material. The buffer particles are then cutting material particles, but not cutting particles. More Description

[0026] The new cutting tool is a 2-in-1 cutting tool, with differently designed tooth sides and tooth tips for efficient machining of different materials. The asymmetry of the tooth tips assigns different tasks to different sides. One side of the tooth tip is optimized for machining a first group of materials, and the other side for machining a second group of materials.

[0027] When machining with a rotating cutting tool, the drive direction determines which of the two sides of the tooth tip comes into contact with the workpiece to be machined for chip formation or chipping. This is the side that leads in the direction of movement of the cutting tool. The other side, which follows in the direction of movement, is initially inactive. This inactive side can then be activated and used to machine a second material by either reversing the drive direction and thus the direction of movement of the cutting tool or by inserting the cutting tool in an opposite second orientation in the cutting machine. In this case, the second side of the tooth tip is active and the first side inactive.

[0028] The materials to be machined are primarily non-metallic, inorganic materials and composite materials. These materials include, in particular, glass, graphite, hard-fired coal, ceramics, silicon, concrete materials, CFRP, sintered materials, and natural stone. However, they can also be metals.

[0029] Some of these materials have comparatively very different properties, which means that some materials can be machined better with a positive tooth tip angle or a tooth tip angle of approximately 0° and other materials with a negative tooth tip angle.

[0030] For example, it is possible to assign one of the connection surfaces on one side to brittle materials and the other connection surface on the other side to ductile (tough) materials.

[0031] Brittle materials include, in particular, ceramics, silicon, glass, cast iron, concrete, masonry bricks, natural stones, brittle metals, and Bakelite. Ductile materials include, in particular, ductile concrete, ductile cast iron, and ductile metals. Ductile materials, i.e., materials with high toughness, exhibit good elastic-plastic deformability before fracture.

[0032] For brittle materials, it is preferable to design and use the cutting tool so that they are machined with a tooth tip with a connecting surface leading in the direction of movement and with a negative tooth tip angle. The resulting more gentle cutting behavior reduces or eliminates the risk of the workpiece breaking during machining.

[0033] For ductile materials, it is preferable to design and use the cutting tool so that the material is machined with a tooth tip having a connecting surface leading in the direction of movement with a positive tooth point angle or a tooth point angle of 0°. The resulting more aggressive cutting behavior is well suited for quickly machining such tough and hard materials.

[0034] The first tooth tip angle is < 0° and the second tooth tip angle is ≥ 0°. The tooth tip angles differ in magnitude, resulting in an asymmetrical tooth tip.

[0035] In particular, the first tooth tip angle can be between < 0° and -80° and the second tooth tip angle between 0° and 20°.

[0036] The first tooth tip angle can be between -1° and -75°, in particular between -1° and -73°, in particular between -1° and -71°, in particular between -40° and -80°, in particular between -40° and -75°, in particular between -40° and -70°, in particular between -40° and -50°, in particular between -42° and -48°, in particular approximately -45°. The second tooth tip angle can be between 0° and 15°, in particular between 0° and 12°, in particular between 0° and 10°, in particular between 3° and 13°, in particular between 5° and 15°, in particular between 8° and 12°, in particular approximately 10°.

[0037] The connecting surfaces (or machining surfaces) of the tooth tips can be flat or uneven. With a negative tooth tip angle, the respective active connecting surface is particularly flat. With a positive tooth tip angle, the respective active connecting surface is particularly at least partially uneven. For example, it is possible for the connecting surface to be flat in the area facing away from the tooth support body and then transition into a circular or other curved area.

[0038] The tooth tips of the teeth of the new cutting tool can be coated with at least two different types of particles that have different properties and are assigned different functions.

[0039] The first type of particles are cutting particles made of cutting material, as is generally known from the state of the art. These cutting particles cause the workpiece to be machined. The new second type of particles are buffer particles, which serve to increase the average distances between the cutting particles.

[0040] In the prior art, when the tooth tip of a cutting tool is coated with cutting particles, there is the problem that so-called nests are formed with a high number of cutting particles per surface and thus a high packing density. This leads to a large number of geometrically undefined cutting edges engaging with the material to be machined in this area during machining, which reduces cutting performance. This causes the feed force to become too great, which in turn causes the cutting tool to be deflected laterally. This prevents the desired straight cut from being achieved. To counteract this, a higher feed rate can be used. However, this leads to these cutting particles being exposed to excessive cutting forces in other areas where the packing density of the cutting particles is lower, and they therefore wear out more quickly.This reduces the service life of the cutting tool.

[0041] Furthermore, the prior art has the problem that with such a high packing density of the cutting particles, there are not sufficient spaces for the material removed by machining of the material to be machined and thus is not transported out of the cutting channel to the required extent.

[0042] These disadvantages of the state of the art are now eliminated or significantly reduced by the new buffer particles of the new cutting tool. The buffer particles prevent or significantly reduce the formation of nests and excessive packing density of the cutting particles. The buffer particles form a kind of spacer between the cutting particles, thus achieving the desired distances between the geometrically indeterminate cutting edges of the cutting particles.

[0043] The buffer particles are located between the cutting particles, although this does not mean that each buffer particle must be positioned exactly between two adjacent cutting particles. The exact position of the particles usually results from a stochastic distribution during the manufacturing process, so that several buffer particles and / or several cutting particles can be arranged adjacent to each other. However, the other arrangement of a buffer particle, namely exactly between two cutting particles, is also possible.

[0044] When the buffer particles are removed later in the manufacturing process, during a separate initialization process, or even at the beginning of machining, the necessary clearances are created between the cutting particles to remove the machined material from the cutting channel.

[0045] The cutting particles and the buffer particles have different physical properties. They are made of different materials and / or have been treated differently, so that they differ in at least one physical property, which allows them to be assigned different functions.

[0046] The different physical properties between cutting particles and buffer particles are selected and utilized to ensure that each particle performs its desired function. In the case of buffer particles, this means that the geometrically indeterminate cutting edges they initially form are later rendered ineffective or removed.

[0047] A first possibility is that the buffer particles have a lower hardness than the cutting particles. This lower hardness is exploited by abrading or removing the buffer particles in a process to which the cutting particles are also subjected, while the cutting particles remain. This process can be the use of the cutting tool for cutting itself or another separate process designed for this purpose. For example, it can be a step in the manufacturing process of the cutting tools that removes the buffer particles in whole or in part.

[0048] The buffer particles can also, alternatively or additionally, have a lower heat resistance than the cutting particles. This lower heat resistance is exploited by subjecting the cutting tool to a heat treatment at such a high temperature that it leads to the complete or partial removal of the buffer particles while retaining the cutting particles.

[0049] The buffer particles can also, alternatively or additionally, have a lower chemical resistance than the cutting particles. This lower chemical resistance is exploited by subjecting the cutting tool to a chemical process in which a substance interacts with both types of particles, resulting in the complete or partial removal of the buffer particles while retaining the cutting particles.

[0050] The cutting particles and buffer particles can be partially embedded in a metal layer, in particular a galvanic deposition layer or a chemical metal deposition layer. The coating of the tooth tip with the cutting particles and buffer particles then takes place as part of a galvanization process or a chemical metal deposition process, in which a metal layer is built up on the tooth tip and the cutting particles and buffer particles are partially embedded in the metal layer in such a way that part of their surface is firmly arranged in the metal layer and the other part of their surface protrudes from the metal layer, so that the geometrically indeterminate cutting edges of the cutting particles can come into contact with the material of the workpiece to be machined when the cutting tool is used.

[0051] The metal layer consists of metal, particularly nickel, chromium, or copper, which has been deposited as metal ions on the tooth tip during electroplating or chemical metal deposition. The metal ions and the metal of the metal layer are not the buffer particles. The buffer particles are additional particles that must be distinguished from the metal ions and the metal of the metal layer.

[0052] The cutting particles and buffer particles can also be partially embedded in a bonding layer of a different design. In particular, the following bonding types can be used: synthetic resin bond, vitrified bond, sintered metal bond, and electroplated bond.

[0053] The coated part of the tooth tip can consist of between approximately 10 and 60%, in particular between approximately 10 and 50%, in particular between approximately 20 and 50%, in particular between approximately 30 and 50%, buffer particles. This proportion relates to the coated area of ​​the tooth tip and not the total area of ​​the tooth tip. Normally, there are also areas of the tooth tip that are covered neither with cutting particles nor with buffer particles. If the tooth tip is coated with a metal layer, as explained above, these areas free of cutting particles and buffer particles are covered by the metal layer. If the cutting particles and buffer particles are roughly the same size, the percentage coverage of the coated part of the tooth tip roughly corresponds to the mixing ratio of these particles in which they are provided for the coating process.The previously mentioned numerical ranges ensure, taking into account the stochastic distribution, that sufficiently large distances between the cutting particles are realized in order to avoid the negative effects during machining described above.

[0054] The cutting particles and the buffer particles can have approximately the same average size. As explained above, the mixing ratio before the coating process then roughly corresponds to the ratio of the particles on the coated tooth tip. However, it is also possible that the cutting particles and the buffer particles have different average sizes.

[0055] The average size of the cutting particles and the average size of the buffer particles can be between about 60 and 800 µm, in particular between about 100 and 800 µm, in particular between about 200 and 800 µm, in particular between about 300 and 800 µm, in particular between about 400 and 800 µm, in particular between about 500 and 800 µm, in particular between about 500 and 700 µm, in particular about 600 µm. Such sizes ensure that the cutting particles provide the desired geometrically indeterminate cutting edges and are spaced apart from each other in the desired manner by the buffer particles.

[0056] The cutting particles can be hard or extremely hard.

[0057] Hard cutting particles are understood to mean in particular those made of corundum (Al 2 O 3 ) or silicon carbide (SiC).

[0058] The high-hardness cutting particles can comprise monocrystalline diamond (MKD), polycrystalline diamond (CVD-D), polycrystalline diamond (PCD), cubic boron nitride (CBN), cutting ceramics, cemented carbide or combinations thereof.

[0059] The buffer particles can comprise monocrystalline diamond (MCD), polycrystalline diamond (CVD-D), polycrystalline diamond (PCD), cubic boron nitride (CBN), silicon carbide, cutting ceramic, cemented carbide, plastic, glass, ceramic, boron carbide, nickel, copper or combinations thereof.

[0060] The cutting particles can be cubic boron nitride (CBN), and the buffer particles can be diamond. Since diamond dissolves at approximately 720 °C and CBN is stable at this temperature, the lower heat resistance is exploited in this case to remove the buffer particles completely or partially.

[0061] The cutting particles may comprise diamond, silicon carbide, cutting ceramic, cemented carbide or combinations thereof and the buffer particles may comprise plastic, glass, ceramic, boron carbide, nickel, copper or combinations thereof.

[0062] The tooth tip can be formed by a separately manufactured attachment element or be co-formed with the tooth. The attachment element is firmly connected to the rest of the tooth via a connecting zone. Suitable connection methods include bonding, soldering, or welding.

[0063] The first connecting surface of the attachment element forming the free tooth tip can be designed essentially the same as the immediately adjacent area of ​​the first connecting surface of the remaining part of the tooth. However, it is also possible for it to be designed differently. The same applies to the second connecting surface.

[0064] The attachment element is designed asymmetrically to form the asymmetrical tooth tip. The immediately adjacent area of ​​the first connecting surface of the remaining part of the tooth can also be designed asymmetrically. However, it is also possible for it to be designed symmetrically.

[0065] The attachment element can be designed as a sintered element. The sintered element consists of a mixture of a binder and the cutting particles. The binder can be, for example, copper, cobalt, iron, bronze, nickel, or mixtures thereof. Buffer particles may also be present.

[0066] It is understood that the cutting tool has not just one tooth of this design, but a plurality, in particular a multiplicity, of such teeth. This may include all of the teeth of the cutting tool. However, it is also possible for additional teeth of a different design to be arranged on the cutting tool.

[0067] The cutting tool has a tooth support body on which the teeth are arranged. The teeth can be formed integrally with the tooth support body or separately. In the latter case, the teeth or tooth tips are firmly connected to the tooth support body or tooth projections in a suitable manner—in particular by welding or soldering. The tooth support body has either an elongated band-shaped or a circular disk-shaped design. In other words, the cutting tool is either a cutting band similar to a saw band or a circular cutting blade similar to a circular saw blade.

[0068] The teeth can be arranged on the tooth support body with a constant pitch. This means that the distance between the teeth remains constant. However, it is also possible for the teeth to be arranged on the tooth support body with a variable pitch. This means that the distances between the teeth vary. In particular, between two and ten different distances between the teeth on the cutting tool can exist.

[0069] The tooth support body is made of a suitable material, particularly a metal material. Examples include spring steel and alloyed tempering steel.

[0070] However, the cutting tool can also be another cutting tool with geometrically undefined cutting edges. The cutting tool can, in particular, be a grinding wheel, a grinding belt, or another tool for grinding, honing, lapping, jet cutting, or sliding cutting.

[0071] The materials to be machined are primarily non-metallic, inorganic materials and composite materials. These materials include, in particular, glass, graphite, hard-fired coal, ceramics, silicon, concrete materials, CFRP, sintered materials, and natural stone. However, they can also be metals.

[0072] Advantageous further developments of the invention emerge from the patent claims, the description and the drawings.

[0073] The advantages of features and combinations of several features mentioned in the description are merely exemplary and can be effective alternatively or cumulatively, without the advantages necessarily having to be achieved by embodiments according to the invention.

[0074] With regard to the disclosure content – ​​not the scope of protection – of the original application documents and the patent, the following applies: Further features can be found in the drawings – in particular the illustrated geometries and the relative dimensions of several components to one another, as well as their relative arrangement and operative connection. The combination of features of different embodiments of the invention or features of different patent claims is also possible, deviating from the chosen references of the patent claims, and is hereby encouraged. This also applies to features that are illustrated in separate drawings or mentioned in their description. These features can also be combined with features of different patent claims.Likewise, features listed in the patent claims may be omitted for further embodiments of the invention, but this does not apply to the independent patent claims of the granted patent.

[0075] The features mentioned in the patent claims and the description are to be understood with regard to their number as meaning that exactly this number or a greater number than the stated number is present, without the need for the explicit use of the adverb "at least." Thus, for example, if reference is made to a tooth, this is to be understood as meaning that exactly one tooth, two teeth, or more teeth are present. These features may be supplemented by other features or may be the only features of which the respective product consists.

[0076] The reference signs contained in the patent claims do not represent a limitation of the scope of the subject-matter protected by the patent claims. They serve solely to make the patent claims easier to understand. BRIEF DESCRIPTION OF THE CHARACTERS

[0077] In the following, the invention is further explained and described with reference to preferred embodiments shown in the figures. Fig. 1 shows a perspective view of a part of a first exemplary embodiment of the new cutting tool. Fig. 2 shows a side view of the cutting tool according to Fig. 1 . Fig. 3 shows a top view of the cutting tool according to Fig. 1 . Fig. 4 shows a front view of the cutting tool according to Fig. 1 . Fig. 5 shows detail B of the cutting tool from Fig. 2 . Fig. 6 shows the cutting tool according to Fig. 1omitting the representation of the cutting particles. Fig. 7 shows the cutting tool according to Fig. 2 omitting the representation of the cutting particles. Fig. 8 shows detail B according to Fig. 5 omitting the representation of the cutting particles. Fig. 9 shows a perspective view of a second exemplary embodiment of the novel cutting tool, omitting the illustration of the cutting particles. Fig. 10 shows a side view of the cutting tool according to Fig. 9 . Fig. 11 shows a perspective view of a third exemplary embodiment of the new cutting tool, omitting the illustration of the cutting particles. Fig. 12 shows a side view of the cutting tool according to Fig. 11 . Fig. 13 shows a side view of a fourth exemplary embodiment of the new cutting tool, omitting the illustration of the cutting particles. Fig. 14shows a perspective view of a part of the cutting tool according to Fig. 13 . Fig. 15 shows detail B from Fig. 13 . Fig. 16 shows detail A from Fig. 13 . Fig. 17 shows a tooth tip of a tooth of a fifth exemplary embodiment of the new cutting tool from the front. Fig. 18 shows a detail of a tooth tip according to the fifth exemplary embodiment of the new cutting tool. Fig. 19 shows a Fig. 8 corresponding detailed view of a tooth tip according to another exemplary embodiment of the new cutting tool. Fig. 20 shows a Fig. 8 corresponding detailed view of a tooth tip according to another exemplary embodiment of the new cutting tool. Fig. 21 shows a Fig. 8 corresponding detailed view of a tooth tip according to another exemplary embodiment of the new cutting tool. Fig. 22 shows a Fig. 8 corresponding detailed view of a tooth tip according to another exemplary embodiment of the new cutting tool. FIGURE DESCRIPTION

[0078] Fig. 1-5 show various views of a first exemplary embodiment of a new cutting tool 1. The cutting tool 1 has a tooth support body 2. In the present case, it is an elongated, band-shaped cutting tool 1, of which only a section is shown. It is understood that the cutting tool 1 extends over the Fig. 1 The cutting tool 1 could, however, also be a circular disk-shaped cutting tool 1. The following explanations also apply to such an embodiment.

[0079] The cutting tool 1 has a plurality of teeth 3 arranged on the tooth support body 2. The teeth 3 can be formed entirely or partially in one piece with the tooth support body 2. In the present example, the teeth 3 are arranged on the tooth support body 2 with a constant pitch. However, they could also be arranged on the tooth support body 2 with a variable pitch.

[0080] The teeth 3 each have a tooth tip 4 that points away from the tooth support body 2. The tooth tip 4 is fully or partially coated with cutting particles 5 in a cutting particle coating region 15. The cutting particles 5 are hard or extremely hard. They can be, for example, corundum (AL 2 O 3 ), monocrystalline diamond (MKD), polycrystalline diamond (CVD-D), etc. For reasons of clarity, only a few of the cutting particles are identified by the reference numeral 5. The end of the cutting particle coating region 15, in which the cutting particles 5 are present, is symbolized by a horizontal line.

[0081] The geometric design of the tooth tip 4 is based on the representations of the Fig. 6 , 7 and 8 easier to recognize. In these figures, in comparison to the corresponding Fig. 1 , 2 and 5The cutting particles are not shown. However, it is understood that cutting particles are always present in these figures and the following figures. Here, too, the end of the area in which cutting particles are present is symbolized by a horizontal line.

[0082] The tooth tips 4 each have a longitudinal central axis 6, a plateau surface 7, a first connecting surface 8, and a second connecting surface 9. The first connecting surface 8 and the second connecting surface 9 directly adjoin the plateau surface 7. However, it would also be possible for an indirect connection to exist, ie, another surface is arranged between the plateau surface 7 and the respective connecting surface 8, 9.

[0083] The tooth tip 4 is formed asymmetrically. This means that the first connecting surface 8 on a first side of the longitudinal center axis 6 (here: the left side) extends at a first tooth tip angle 10 with a first value to the plateau surface 7, and the second connecting surface 9 on the opposite second side of the longitudinal center axis 6 (here: the right side) extends at a second tooth tip angle 11 with a different second value to the plateau surface 7 (see Fig. 8 ).

[0084] The tooth tip angles 10, 11 are determined relative to a vertical line. In this exemplary embodiment, the value of the first tooth tip angle 10 is approximately 45° and the value of the second tooth tip angle 11 is approximately 20°.

[0085] When the cutting tool 1 moves in a first direction of movement 13 (here: to the left), the first connection surface 8 is the active cutting surface, the first to come into contact with the workpiece material to be machined. Viewed in this first direction of movement 13, the first tooth tip angle 10 is a negative tooth tip angle. When cutting in this first direction of movement 13, the cutting tool 1 exhibits gentle cutting behavior and is particularly well suited for cutting brittle materials.

[0086] If, however, the cutting tool 1 is driven and moved in the opposite second direction of movement 14 (here: to the right), the second connection surface 9 is the active cutting surface. This can be achieved, for example, by switching the direction of rotation of the motor of the cutting machine driving the cutting tool 1. Another possibility for activating the second connection surface 9 is to reverse the orientation (arrangement) of the cutting tool 1 in the cutting machine. In both cases, the active cutting surface now has a positive tooth point angle, resulting in more aggressive cutting behavior. One and the same cutting tool 1 is now particularly well suited for cutting ductile materials.

[0087] In Fig. 9 and 10A second exemplary embodiment of the novel cutting tool 1 is shown. This embodiment has many similarities with the previously described embodiments, so that, to avoid unnecessary repetition, reference is made to the relevant explanations given above. Similar statements also apply to the other embodiments described below.

[0088] In contrast, there is a variable pitch of the teeth 3 on the tooth support body 2, which is indicated by the longer dash-dotted lines in Fig. 10 is understandable. The distance between the first tooth 3 and the second tooth 3 is greater than the distance between the second tooth 3 and the third tooth 3 (see Fig. 10(seen from left to right). The distance between the third tooth 3 and the fourth tooth 3 is again smaller than the distance between the second tooth 3 and the third tooth 3. However, there could also be another variable pitch.

[0089] In Fig. 11 and 12 A third exemplary embodiment of the new cutting tool 1 is shown. Here, the teeth 3 are designed differently from one another. In addition to the first type of teeth 3 described above ( Fig. 12 : the second tooth 3 and the third tooth 3 seen from the left) there is a second type of teeth 3 ( Fig. 12: the first tooth 3 and the fourth tooth 3 seen from the left), in which both tooth tip angles 10, 11 are negative. The tooth tip 4 of these teeth 3 is also asymmetrical because the values ​​of the tooth tip angles 10, 11 are different. The value of the first tooth tip angle 10 of the first tooth 3 is approximately 45°, while the value of the second tooth tip angle 11 of the first tooth 3 is approximately 20°. In the case of the fourth tooth 3, the value of the first tooth tip angle 10 is also approximately 45°, while the value of the second tooth tip angle 11 of the fourth tooth 3 is approximately 10°. The teeth 3 are arranged on the tooth support body 2 with a constant pitch. However, they could also be arranged with a variable pitch.

[0090] In Fig. 13-16Various views of a fourth exemplary embodiment of the novel cutting tool 1 are shown. Here, the cutting tool 1 is designed as a circular cutting blade, ie, the tooth support body 2 is circular disk-shaped.

[0091] The teeth 3 are arranged with a variable pitch on the tooth support body 2. The first tooth tip angle 10 is negative. Its value is approximately 45°. The second tooth tip angle 11 is approximately 2°.

[0092] Fig. 17 and 18show a fifth exemplary embodiment of the novel cutting tool 1. In this case, the tooth tip 4 is coated not only with cutting particles 5, but also with buffer particles 16. The cutting particles 5 and the buffer particles 16 are fixedly arranged in a metal layer 17 and partially embedded therein. They thus partially protrude from the metal layer 17. The metal layer 17 is, in particular, a galvanic deposition layer or a chemical metal deposition layer.

[0093] The cutting particles 5 and the buffer particles 16 differ in terms of their material and the function they perform. For more information, please refer to the detailed explanations above.

[0094] The cutting particles 5, the buffer particles 16, and the metal layer 17 together form a coating area 18, which provides the desired cutting function of the cutting tool 1 by containing the necessary cutting edges. This coating area 18 extends over the entire tooth tip 4 or a portion of the tooth tip 4. This is the coated portion of the tooth tip 4.

[0095] It is understood that the representations of the Fig. 17 and 18These are not representations to scale, and the geometry of the particles 5, 16 looks or can look different in practice. The particles 5, 16 can also have approximately the same geometry. The illustration is intended to make the particles 5, 16 distinguishable and to illustrate that the arrangement of the buffer particles 16 creates free spaces between the cutting particles 5 that are not present, or not present to this extent, in a pure arrangement of cutting particles 5—as is known in the prior art.

[0096] For further possible design of the cutting tool 1 and the tooth tips 4, please refer to the explanations on the Fig. 1-16 In other words, the embodiments of the cutting tool 1 according to Fig. 1-16 which have buffer particles 16.

[0097] Fig. 19-22 show Fig. 8Corresponding detailed views of further exemplary embodiments of the tooth tip 4 of the cutting tool 1. In these embodiments, the tooth tip 4 is formed or co-formed by a separately manufactured attachment element 19. The attachment element 19 is firmly connected to the remaining part of the tooth 3 via a connection zone 20. Suitable connection methods include, for example, gluing, soldering, or welding. The connection zone 20 is symbolically represented by the thicker black line.

[0098] It can be seen from the various embodiments that the first connection surface 8 of the attachment element 19 forming the free tooth tip 4 can be designed essentially identically to or differently from the immediately adjacent region of the first connection surface 8 of the remaining part of the tooth 3. The same applies to the second connection surface 9.

[0099] The attachment element 19 can be designed as a sintered element. The sintered element consists of a mixture of a binder and the cutting particles. The binder can be, for example, copper, cobalt, iron, bronze, nickel, or mixtures thereof. Buffer particles may also be present. LIST OF REFERENCE SYMBOLS

[0100] 1Cutting tool 2Tooth support body 3Tooth 4Tooth tip 5Cutting particle 6Longitudinal center axis 7Plateau surface 8First connection surface 9Second connection surface 10First tooth tip angle 11Second tooth tip angle 12Direction of movement 13First direction of movement 14Second direction of movement 15Cutting particle coating area 16Buffer particle 17Metal layer 18Coating area 19Attachment element 20Connection zone

Claims

1. A machining tool (1) embodied as a saw band or saw blade, the machining tool (1) including a tooth (3) having a tooth tip (4) being covered with cutting particles (5) to form a plurality of geometrically undefined cutting portions, wherein the tooth tip (4) includes a longitudinal center axis (6), a plateau surface (7), a first connecting surface (8) and a second connecting surface (9), wherein the first connecting surface (8) and the second connecting surface (9) are directly or indirectly connected to the plateau surface (7), and the first connecting surface (8) extends at a first side of the longitudinal center axis (6) under a first tooth tip angle (10) having a first value with respect to the plateau surface (7), and the tooth tip (4) is designed to be asymmetrical, the second connecting surface (9) extends at an opposite second side of the longitudinal center axis (6) under a second tooth tip angle (11) having a different second value with respect to the plateau surface (7), the first tooth tip angle (10) is < 0° as seen in a first sense of direction of movement (13) in which the first connecting surface (8) precedes the second connecting surface (9), and the second tooth tip angle (11) is ≥ 0° in an opposite second sense of direction of movement (14) in which the second connecting surface (9) precedes the first connecting surface (8) characterized in that when the machining tool (1) moves in a first sense of direction of movement (13) the first connecting surface (8) is the active machining surface which first comes into contact with the workpiece which is to be machined, and when the machining tool (1) moves in the opposite second sense of direction of movement (14) the second connecting surface (9) is the active machining surface, and the first tooth tip angle (10) is between < 0° and -80° and the second tooth tip angle (11) is between 0° and 20°.

2. The machining tool (1) of claim 1, characterized in that the first tooth tip angle (10) is between -1° and -75°, especially between -1° and -73°, especially between -1° and -71°, especially between -40° and -80°, especially between -40° and -75°, especially between -40° and -70°, especially between -40° and -50°, especially between -42° and -48°, especially approximately -45°, the second tooth tip angle (11) is between 0° and 15°, especially between 0° and 12°, especially between 0° and 10°, especially between 3° and 13°, especially between 5° and 15°, especially between 8° and 12°, especially approximately 10°.

3. The machining tool (1) of one of the preceding claims, characterized in that the tooth tip (4) is furthermore covered with buffer particles (16) of a different material than the cutting particles (5) and the buffer particles (16) are located between the cutting particles (5).

4. The machining tool (1) of claim 3, characterized in that the cutting particles (5) and the buffer particles (16) are partly embedded in a metal layer (17), especially a galvanic deposition layer or a chemical deposition layer.

5. The machining tool (1) of claim 4, characterized in that the metal layer (17) consists of metal, especially nickel, chrome or copper, that has deposited on the tooth tip (4) as metal ions during galvanization or chemical metal deposition and that the metal ions and the metal of the metal layer (17) are not the buffer particles (16).

6. The machining tool (1) of at least one of claims 3 to 5, characterized in that the covered part of the tooth tip (4) consists of between approximately 10 and 60%, especially between approximately 10 and 50 %, especially between approximately 20 and 50 %, especially between approximately 30 and 50 %, of buffer particles (16).

7. The machining tool (1) of at least one of claims 3 to 6, characterized in that the cutting particles (5) and the buffer particles (16) have approximately the same average size.

8. The machining tool (1) of at least one of claims 3 to 7, characterized in that the buffer particles (16) have a lower hardness than the cutting particles (5).

9. The machining tool (1) of at least one of claims 3 to 8, characterized in that the buffer particles (16) have a lower heat resistance than the cutting particles (5).

10. The machining tool (1) of at least one of claims 3 to 9, characterized in that the cutting particles (5) include cubic bornitride (CBN) and the buffer particles (16) include diamond, or the cutting particles (5) include diamond, silicon carbide, cutting ceramics, hard metal or combinations thereof and the buffer particles (16) include plastic, glass, ceramics, boron carbide, nickel, copper or combinations thereof.

11. The machining tool (1) of at least one of the preceding claims, characterized in that a plurality, especially a multitude, of such teeth (3) is arranged at the machining tool (1).

12. The machining tool (1) of at least one of the preceding claims, characterized by a tooth supporting body (2) being designed to be band-shaped or to have the shape of a circular disk.

13. The machining tool (1) of claim 3 and 4, characterized in that the teeth (3) are arranged at the tooth supporting body (2) with a variable division.

14. A method of machining two workpieces of different materials with exactly one machining tool (1) being embodied as a saw band or saw blade, the machining tool (1) including a tooth (3) having an asymmetrical tooth tip (4) being covered with cutting particles (5) to form a plurality of geometrically undefined cutting portions, especially a machining tool (1) of at least one of the preceding claims, comprising the steps of: inserting the machining tool (1) in a first orientation into a machining apparatus including a motor; machining a first workpiece of a first material with the machining tool (1) in the first orientation by driving the machining tool (1) in a first sense of direction of movement (13); and a1. switching the motor to drive the machining tool (1) in an opposite second sense of direction of movement (14), and a2. machining a second workpiece of a different second material with the machining tool (1) in the first orientation; or b1. removing the machining tool (1) from the machining apparatus, b2. inserting the machining tool (1) in an opposite second orientation in the machining apparatus, and b3. machining a second workpiece of a different second material with the machining tool (1) in the second orientation by driving the machining tool (1) in the first sense of direction of movement (13).