DE202022106292U1 - tool and workpiece - Google Patents

Abstract

Tool (10), in particular a stamping or forming tool, structured according to a method for producing a tool (10) for machining a workpiece (12), in particular a stamping or forming tool,
in which a metallic tool blank (11) is provided in a laser processing device (14) and
the laser processing device (14) structures the tool blank (11) on a tool surface (13) by means of interference of at least two laser beams (17, 18, 26),
wherein the at least two laser beams (17, 18, 26) at least at times have pulse durations of at most 15 ps and
a tool profile (20) with at least one depression (22) being produced by the structuring on the tool surface (13).

Description

The invention relates to a tool and a workpiece.

The invention is concerned with the task of at least partially structuring a workpiece, in particular a metallic workpiece such as a component, with a topography in the lower micron and/or nanometer range. A large number of biological surfaces are structured on this scale, each of which produces its own functional surface properties, such as altered wetting (lotus, thorny devil), color effects (butterfly wing scales), reduced friction (shark skin), reduced adhesion/active killing of germs and pathogens (cicada and dragonfly wings). The topographies of this magnitude are therefore also referred to as biomimetic topographies. In addition to the topography of the surface itself, many of these surface properties are also influenced by the surface chemistry.

In the context of the industrial surface structuring of workpieces with topographies of the order of magnitude mentioned, it is currently only possible to process the workpieces directly using at least two laser beams interfering with one another. As a result of this essentially thermal form of processing, the surface of the workpiece undergoes a chemical modification in addition to the topographical modification during processing, which can counteract the desired function or further processing of the workpiece. In this respect, the desired functionalization of the workpiece surface cannot always be guaranteed by means of direct processing by the interfering laser beams, especially in the case of metallic tools, since the thermal effect of the laser radiation is particularly pronounced here due to the electromagnetic absorption properties of metals.

The object of the invention is therefore to develop a tool with which an improved surface topography of the workpiece can be obtained in industrial use, in particular with which a micro- and / or nanoscale topographical surface functionalization of the workpiece can be realized, the extended design options with reduced thermal and chemical influence on the workpiece compared to direct processing using laser interference. The same applies to the processed workpiece itself.

The object of the invention is achieved by a tool according to claim 1 and by a workpiece according to claim 14.

The tool according to the invention is structured according to a method for producing the same in such a way that a metallic tool blank is provided in a laser processing device and the laser processing device structures the tool blank on a tool surface by means of interference of at least two laser beams, the at least two laser beams at least temporarily having pulse durations of at most 15 ps have and wherein a tool profile with at least one recess is generated by the structuring on the tool surface.

The workpiece according to the invention is machined with a tool according to the invention, the workpiece being plastically deformed at least in regions by means of the tool and being provided with a workpiece profile that corresponds at least in regions to the tool profile.

The invention is based on the basic idea that, moving away from the already known direct structuring of the workpiece by means of the interfering laser radiation, the tool is now first produced by the structuring described and then, in a next step, the workpiece itself can be structured. The essential core of the invention is that an interaction of the laser radiation with the workpiece surface that is ultimately to be structured is avoided, so that the disadvantageous chemical modification of the workpiece surface known from the prior art does not occur, although its desired functionality is retained or can be guaranteed in the first place . The invention uses the structuring of the workpiece surface, in particular a metallic substrate surface, for example in the lower micron and/or nanometer range by plastic deformation, which does not affect the surface chemistry. Thus, only the topography of the metallic substrate is modified without affecting the basic chemical interaction with substances in contact, e.g. wetting by water or oils. The present invention makes a previously unfeasible purely topographical surface functionalization accessible for industrial use, which is particularly suitable for further processing of the surfaces via electroplating, PVD, etc.

Investigations by the applicant have shown that the essentially plastic machining of the workpiece carried out within the scope of the invention does not result in any significant chemical modification of the workpiece, as was previously the case with the known methods from the prior art. For example, studies by the applicant have shown that the wetting properties of a workpiece according to the invention differ significantly from the wetting properties of a workpiece processed by means of direct laser interference structuring, which can be attributed to the avoidance of chemical surface modification in the case of the invention.

Another basic idea of the invention is that the use of mutually interfering laser beams for manufacturing the tool by structuring it allows a large tool surface to be processed in a short time, with the result that the process efficiency of the method is improved. In particular, the tool can be provided with a full-surface surface structure in the micro and/or nanometer scale range in a short processing time, which leads to a significantly higher process efficiency and thus lower tool costs compared to other existing high-precision processing methods such as focused laser or ion beams. This advantage is particularly evident in comparison to structuring the tool with only a single laser beam, which has to be directed along the entire tool surface to be structured, which is laborious and slow.

Further advantages compared to the direct structuring of the workpieces are in particular a greater variety of possible topographical geometries of the workpieces, for example through partial molding with low contact pressure and multiple embossing with variable structuring of the tool, as well as the lower process time for structures with high depth or aspect ratio. In particular, the latter structural form can sometimes lead to very long process times in a purely ablative laser process, while embossing can achieve this in one stroke.

Since the workpiece is processed by the structured tool and no longer directly by means of laser radiation, as is the case with the known methods, a significant improvement in occupational safety in industrial applications is also achieved.

By using laser pulses with a maximum pulse duration of 15 ps, thermal effects in the interaction between the laser radiation and the tool surface are largely avoided, which in particular prevents the occurrence of melting and thermally induced material damage, in particular stress cracks. It is known that with shorter pulse durations, thermal effects are increasingly neglected and the tool is increasingly processed mechanically. This effect is therefore also referred to as cold ablation. From this point of view, it can be provided that the temporal pulse duration of the laser beams is at most 10 ps, so that even fewer thermal effects occur. Besides, the accuracy of the structure is improved. For the same reason, it is most preferably provided that the temporal pulse duration of the laser radiation is at most 1 ps, as a result of which an even better surface quality of the tool structuring can be obtained. A pulse duration of between 100 fs and 15 ps, in particular between 100 fs and 1 ps, is preferably provided. Furthermore, the power of the laser radiation can be between 1 W and 500 W and/or the energy of the pulses of the laser radiation can be between 10 μJ and 100 mJ. When creating the structuring, between 10 and 1000 individual pulses can be superimposed in a spatial area in order to obtain high structure aspect ratios through a correspondingly high material removal.

Furthermore, it can be provided that precisely two laser beams interfering with one another are used to structure the tool. A further development of the invention provides that three laser beams interfering with one another are used, as a result of which a structuring of the tool with indentations in a hexagonal pattern can be produced, for example. In this case, the structuring has three axes along the surface, along which the indentations are each arranged in a lateral period, the lateral periods for the three axes being identical for the purposes of the invention in the case of the hexagonal pattern. In addition, the procedure can be that four laser beams interfering with one another are used in order to produce a square pattern of the depressions when structuring the tool. Finally, it can be provided that at most nine laser beams interfering with one another are used.

The tool can be a stamping or forming tool, in which case the processing of the workpiece can be a stamping or forming process, in particular an embossing process.

The at least one depression is preferably produced with a dimension, in particular with a depth in relation to an unstructured area of the tool surface, of between 10 nm and 50 μm, in particular between 100 nm and 15 μm. In further embodiments of the invention it can be provided that the dimension of the recess corresponds to its length in the x- and/or y-direction, with the y-direction of the offset direction of the Corresponds to depressions, while the x-direction is arranged perpendicularly thereto. The x and y directions are each perpendicular to the normal of the tool surface and thus each extend along the tool surface. Within the meaning of the invention, a combination of the x and y directions can also be designated as a dimension, which to this extent corresponds to a generally lateral direction.

At least two depressions with essentially identical dimensions, in particular with essentially identical depths, are preferably produced. Within the meaning of the invention, two dimensions have essentially identical dimensions if their deviations do not exceed the machining tolerance that is customary in comparable methods. At least two adjacent depressions can be arranged at a distance of 10 nm to 50 μm, in particular 100 nm to 15 μm. With the tool structured in this respect, structural geometries in the range between 10 nm and 50 μm, in particular between 100 nm and 15 μm, can be realized on the workpiece at an industrially relevant process speed while at the same time ensuring reproducibility.

Provision is preferably made for at least one group of indentations to be produced in a periodic pattern on the tool surface, since this structure can be produced particularly easily by means of the laser beams interfering with one another. In the context of the present invention, the period designates the distance between two identical structural features of different depressions of the periodic pattern, ie for example the distance between the beginning of a first depression of the periodic pattern and the beginning of the adjacent depression of the same periodic pattern. Alternatively or additionally, the period in the sense of the invention can denote the distance between a center point of the first depression of the periodic pattern and the center point of the depression of the same periodic pattern that is adjacent thereto. Since the indentations of the periodic pattern are laterally offset, the term "lateral period" is also used within the meaning of the invention, which, as already stated, designates the distance between recurring structural features of adjacent indentations in the periodic pattern.

In an advantageous development of the invention, it can be provided that the group of indentations in the periodic pattern on the tool surface is produced with a period between 10 nm and 50 μm, in particular between 100 nm and 15 μm, in at least one direction along the tool surface. Periodic structuring with a lateral period of this magnitude enables the advantageous surface functionalities mentioned at the outset to be formed, with which the workpiece is ultimately also to be provided. The group of depressions in the periodic pattern can also have different periods in different directions, for example when three, four or more laser beams interfering with one another are used to structure the tool. In an advantageous development, the group of depressions in the periodic pattern has identical periods in two different directions. It can further be provided that the group of depressions in the periodic pattern has identical periods in three different directions, which corresponds, for example, to a hexagonal arrangement of the depressions. The group of depressions is designed, for example, as a sinusoidal line structure in which depressions and elevations are each arranged one behind the other in the same lateral period.

At least one group of indentations is preferably produced on the tool surface with a linear course and/or with a rectangular, preferably square basic shape and/or with a circular basic shape. The basic shape of the depressions can be polygonal, in particular hexagonal. As a special case, the indentations can be designed as lines, which can be arranged offset in particular perpendicularly to the direction of extension and/or with a defined period.

Provision is preferably made for at least two first depressions, in particular a first group of depressions, to be produced with a first lateral period of between 10 nm and 50 μm, in particular between 100 nm and 15 μm, and at least two second depressions, in particular a second group of Depressions are generated with a second lateral period, wherein in particular the second lateral period is smaller than the first lateral period. The first lateral period can be between 100 nm and 999 μm. However, the second lateral period can also be greater than or identical to the first lateral period. The second group of depressions can be configured similarly to the first group of depressions in a mathematical sense, so that the second group of depressions results from the first group of depressions by means of at least one mathematical similarity transformation, for example displacement, rotation, stretching and/or scaling. The second group of indentations preferably corresponds to a rotation of the first group of indentations about an axis perpendicular to the tool surface of 90°.

Alternatively or additionally, it can be provided that at least two first depressions, in particular a first group of depressions, with a first dimension between 10 nm and 50 μm, in particular between 100 nm and 15 μm, are produced and at least two second depressions, in particular a second Group of depressions are produced with a second dimension, wherein the second dimension is in particular smaller than the first dimension. As already mentioned, the dimensions of the depression in the context of the invention can correspond to its depth.

In addition, it can be provided that, in addition to the second depressions, at least two third depressions, in particular a third group of depressions, are produced with a third lateral period and/or a third dimension, the third lateral period and/or the third dimension are in particular smaller than the second lateral period and/or the second dimension. In further developments, up to ten groups of indentations, each with a lateral period and/or a dimension, can be produced, with the lateral period and/or the dimension of a group always being smaller than the lateral period and/or the dimensions of the previous groups.

The area of the second depressions, in particular the second group of depressions, preferably at least partially overlaps the area of the first depressions, in particular the first group of depressions. The same applies to any third depressions that may be produced, in particular the third group of depressions. Such an overlap makes it possible to combine structures with different lateral periods and/or dimensions, in particular to modulate them mathematically, and to provide the tool with complex surface structures that are not possible with a simple structure. This expands the possibilities of surface functionalization of the tool, and thus also those of the workpiece.

The first depressions, in particular the first group of depressions, and the second depressions, in particular the second group of depressions, are preferably produced in a single work step or in separate work steps. The production of the first indentations and the second indentations in a single work step results in an increase in the process speed. In contrast, the configuration of the production of the first indentations and the second indentations in separate work steps includes, in particular, that the tool surface is structured with different interference patterns. For example, it can be provided that the tool is moved between two work steps. Provision can preferably be made for the tool to be rotated between two work steps, in particular by 90°, for example about an axis of extent of the tool, so that indentations, for example as cross structure patterns and/or so-called Penrose structure patterns, can be formed particularly easily. The pits of the second group may be arranged perpendicularly to the pits of the first group such that the lateral period of the second group of pits is arranged perpendicular to the lateral period of the first group of pits. In addition, the lateral period of the second group of indentations can be aligned parallel to the lateral period of the first group of indentations or enclose an angle between 0° and 180°.

The second group of indentations is preferably produced by polarization of the laser beams selected depending on the material of the tool to be structured, as a result of which in particular laser-induced periodic surface structuring can be formed, in particular in a joint work step with the formation of the first group of indentations. The lateral period of the second group of depressions corresponds, for example, at most to the wavelength of the laser beams used. The polarization of the laser beams can be aligned linearly, with the polarization vector being arranged essentially perpendicular to the extension direction of the laser-induced periodic surface structuring and/or parallel to the lateral period associated with the laser-induced periodic surface structuring. In addition, the direction of the polarization vector of the laser beams can be aligned at an angle between 0° and 180° relative to the lateral period of the first group of indentations, so that the alignment of the polarization vector of the laser beams changes the arrangement of the second group of indentations, in particular relative to the first group of wells is adjustable.

For example, it can be provided that the first indentations, in particular the first group of indentations, are generated by means of interference of the at least two laser beams, the second indentations, in particular the second group of indentations, by means of interference of at least two laser beams and/or by means of a single Laser beam are generated. This means that the first depressions are always produced with the laser beams interfering with one another, while this is not necessarily the case for the production of the second depressions must. The production of the second indentations by means of a single laser beam can be useful when the number of second indentations is small compared to the number of first indentations and/or when the area of the second indentations is small compared to the area of the first indentations. If the second depressions are also produced by means of laser beams interfering with one another, it can be provided that the number of laser beams interfering with one another differs in comparison with the production of the first depressions or is identical to these.

The tool blank is preferably coated before structuring and/or the tool after structuring, for example with a hard material layer, in particular with a carbon layer. An amorphous carbon layer is most preferably used as the coating. After structuring the tool, further surface functionalization can take place, for example by means of thermal processes and/or by chemical vapor deposition (CVD) and/or by physical vapor deposition (PVD), for example to smooth the surface of the tool by removing unwanted substructures or roughness . In a further configuration it can be provided that the tool surface is polished before structuring.

The tool preferably has at least one component made from a hard metal, which has a plurality of hard material particles and a binder matrix. Hard metals are metal matrix composite materials, which are also referred to as hard metal composite materials. The hard material particles present in the hard metal have at least one member from the group diamond, nitride, carbide, oxide and have a comparatively high level of hardness, but a comparatively low level of toughness. For better workability, the hard material particles are therefore embedded in a binder matrix which contains at least one member from the group cobalt, nickel, molybdenum or a combination and which increases the ductility of the resulting hard metal. Cemented carbides are harder than pure metals, alloys and hardened steels and therefore have higher wear resistance, which also applies to the tool with a cemented carbide component.

According to the invention, the metallic tool blank can have or consist of a component made of a hard metal composite, which has a ceramic-metal composite, for example. The tool blank preferably has a component made of tungsten carbide-cobalt hard metal (WC-Co), which can optionally contain components made of vanadium carbide (VC), chromium carbide (Cr ₃ C ₂ ) and/or tantalum-niobium carbide. The tool can have a coating of a hard metal material and/or diamond and/or amorphous carbon.

Alternatively or additionally, the tool preferably has at least one component made from a thermally treated tool steel. By choosing the thermal treatment, the properties of the tool steel can be adapted to the use of the tool. For example, the tool has a component made of tempered tool steel.

The tool can have a hard material layer, preferably a carbon layer, most preferably a tetrahedral, hydrogen-free carbon layer, at least in regions on the tool surface. In particular, the tool surface has an amorphous carbon layer, which is also referred to as DLC (diamond-like carbon) or diamond-like carbon. Alternatively or additionally, the carbon layer can have a graphite layer and/or a diamond layer. The surface of the tool can be further functionalized by the formation of a carbon layer on the tool surface. In particular, the friction and wear properties of the tool can be optimized for tribological applications.

The workpiece according to the invention can provide that the plastic deformation of the workpiece takes place in that the tool is pressed or pressed onto the workpiece, in particular with a user-defined press-in depth and/or with a user-defined press-in pressure. The resulting workpiece profile is produced by means of pressing, pressing or embossing. The tool according to the invention can be integrated into an industrial press. The structure depth and/or the structure geometry of the workpiece profile can be varied very easily and efficiently thanks to the simple process design via setting the press-in pressure, which is of particular interest for tribological applications. In addition, by adjusting the press-in pressure, variable aspect ratios can be implemented when structuring the workpiece with negligibly different process times. The workpiece profile is in particular at least partially mathematically similar, for example at least partially complementary, to the tool profile, which within the meaning of the invention includes the workpiece profile corresponding at least to a partial negative impression of the tool profile. In particular, the workpiece profile is an at least partial, in particular complete, molding of the tool profile. Because the editing of the work piece based on the geometry of the structuring of the tool, essentially identical structures can be produced on different workpiece materials. The workpiece to be machined is preferably fed to the tool, in particular by means of a belt guide.

An advantageous development of the invention can provide that the workpiece, at least in the area assigned to the tool, is plastically deformed in a single processing step, whereby the workpiece profile is provided with a structure that is at least partially complementary to the tool profile. The workpiece can be completely machined by successively moving the tool laterally after one machining step relative to the workpiece surface and machining the workpiece again in one machining step.

The workpiece is preferably plastically deformed by means of the tool in at least two processing steps, with the tool plastically deforming the workpiece along a processing axis with a first processing depth in a first processing step, and with the tool plastically deforming the workpiece along the processing axis with a second processing depth in a second processing step deformed and in particular the first processing depth differs from the second processing depth. The second processing depth is in particular smaller than the first processing depth. Several processing steps with corresponding processing depths can be provided, the processing depth of a processing step being in particular smaller than the processing depth of the preceding processing step. The machining axis is preferably aligned perpendicular to the workpiece surface. Due to the multiple processing of the workpiece with different processing depths, which correspond, for example, to inset depths, complex workpiece topographies can be produced that cannot be produced with a single processing step. In another embodiment of the invention, the second machining depth can be identical to the first machining depth. Provision can be made for the same tool to be used in two processing steps, with the tool being moved in translation and/or rotation between the two processing steps. The tool is preferably moved through 90° between the two rotation steps, in particular around an axis of extension of the tool. In a further embodiment of the invention, the tool is moved in translation, in particular between the processing steps, successively over the entire region of the workpiece to be structured. A suitable tool guide can be designed for this purpose, for example.

The first machining step is preferably carried out with a first tool and the second machining step with a second tool, the first tool and/or the second tool being a tool according to the invention. Both tools are preferably tools according to the invention. In a development of the invention, it can be provided that the structuring of the tool surfaces of the tools differ from one another at least in certain areas. By processing the workpiece using two different tools, in particular with two different or even identical processing depths, complex surface topographies can be produced, such as surface topographies that correspond to combinations, in particular in the mathematical sense modulations, of topographies of different magnitudes. In addition, further processing steps can be provided with tools, which are preferably tools according to the invention.

The second tool preferably has a periodic structure with a lateral period that is in particular smaller than the lateral period of the periodic structure of the first tool, which, in the sense of the invention, includes the dimensions of the structure and also its lateral period. It is thus provided in particular that the periodic structure of the second tool has a smaller lateral period than the periodic structure of the first tool. The lateral period of the periodic structure of the second tool can also be greater than or identical to the lateral period of the periodic structure of the first tool.

It is preferably provided that the press-in pressure of one processing step differs from the press-in pressure of another processing step in order, for example, to provide the workpiece with a complex surface topography even with the structuring of a single tool. The press-in pressure used is preferably between 100 MPa and 100,000 MPa, with the press-in pressure actually used being to be selected as a function of the mechanical strength of the workpiece to be machined. In a further embodiment of the invention, the press-in pressure of one processing step is identical to the press-in pressure of another processing step.

The workpiece is preferably plastically deformed by means of a vibrating movement of the tool, in particular along the machining axis. The frequency of the vibration is preferably between 20 kHz and 10 GHz thus in the ultrasonic range. Findings of the applicant have shown that the springback of the workpiece material is reduced by the vibration of the tool during the pressing process, so that the molding of the structuring of the tool on the workpiece is improved.

The workpiece is preferably machined using the tool at a temperature of at most 1200° C., in particular free of any external heat input.

The workpiece according to the invention preferably has a structure which is at least partially similar, in particular at least partially complementary, to the structure of the tool.

The workpiece has in particular a component made of brass (CuZn) with in particular a zinc content of essentially 30% (CuZn30), which has a particularly pronounced plastic deformability.

• 1 eine schematisch dargestellte Ausgestaltung eines Verfahrens zur Herstellung eines Werkzeugs sowie ein erfindungsgemäßes Werkzeug,
• 2 eine schematisch dargestellte Ausgestaltung eines Verfahrens zur Bearbeitung eines Werkstücks und ein erfindungsgemäßes Werkstück,
• 3 eine weitere Ausgestaltung des Verfahrens zur Herstellung eines Werkzeugs sowie ein erfindungsgemäßes Werkzeug,
• 4 eine weitere Ausgestaltung des Verfahrens zur Bearbeitung eines Werkstücks und ein erfindungsgemäßes Werkstück,
• 5 eine weitere Ausgestaltung des Verfahrens zur Herstellung eines Werkzeugs sowie ein erfindungsgemäßes Werkzeug,
• 6 eine weitere Ausgestaltung des Verfahrens zur Bearbeitung eines Werkstücks und ein erfindungsgemäßes Werkstück,
• 7 eine weitere Ausgestaltung des Verfahrens zur Herstellung eines Werkzeugs sowie ein erfindungsgemäßes Werkzeug,
• 8 eine weitere Ausgestaltung des Verfahrens zur Bearbeitung eines Werkstücks und ein erfindungsgemäßes Werkstück,
• 9 eine weitere Ausgestaltung des Verfahrens zur Herstellung eines Werkzeugs sowie ein erfindungsgemäßes Werkzeug,
• 10 eine weitere Ausgestaltung des Verfahrens zur Bearbeitung eines Werkstücks und ein erfindungsgemäßes Werkstück,
• 11 bis 14 eine weitere Ausgestaltung des Verfahrens zur Herstellung eines Werkzeugs, des erfindungsgemäßen Werkzeugs, sowie eine weitere Ausgestaltung des Verfahrens zur Bearbeitung eines Werkstücks und des erfindungsgemäßen Werkstücks,
• 15, 16 eine weitere Ausgestaltung des Verfahrens zur Bearbeitung eines Werkstücks und des erfindungsgemäßen Werksstücks und
• 17, 18 eine weitere Ausgestaltung des Verfahrens zur Bearbeitung eines Werkstücks und des erfindungsgemäßen Werksstücks.

Further advantages and features of the invention result from the claims and from the following description, in which an exemplary embodiment of the invention is explained in detail with reference to the drawings. show:

• 1 a schematically illustrated embodiment of a method for manufacturing a tool and a tool according to the invention,
• 2 a schematically illustrated embodiment of a method for machining a workpiece and a workpiece according to the invention,
• 3 a further embodiment of the method for producing a tool and a tool according to the invention,
• 4 a further embodiment of the method for machining a workpiece and a workpiece according to the invention,
• 5 a further embodiment of the method for producing a tool and a tool according to the invention,
• 6 a further embodiment of the method for machining a workpiece and a workpiece according to the invention,
• 7 a further embodiment of the method for producing a tool and a tool according to the invention,
• 8th a further embodiment of the method for machining a workpiece and a workpiece according to the invention,
• 9 a further embodiment of the method for producing a tool and a tool according to the invention,
• 10 a further embodiment of the method for machining a workpiece and a workpiece according to the invention,
• 11 until 14 a further embodiment of the method for manufacturing a tool, the tool according to the invention, and a further embodiment of the method for machining a workpiece and the workpiece according to the invention,
• 15 , 16 a further embodiment of the method for machining a workpiece and the workpiece according to the invention and
• 17 , 18 a further embodiment of the method for machining a workpiece and the workpiece according to the invention.

1 shows an embodiment of a method for producing a tool 10 based on three images of the tool 10. In 1 In the illustration on the left, the tool 10 is arranged in the still unmachined state as a tool blank 11, which in the exemplary embodiment shown is essentially a cylinder made of a tungsten carbide-cobalt hard metal (WC-Co) and was produced via spark erosion. Subsequent machining of a workpiece 12 should take place through the top surface 13 of the tool 10, so that the top surface 13 of the tool blank 11 has an in 1 not shown coating is provided from an amorphous carbon, which is also referred to as diamond-like carbon (DLC).

To produce the tool 10, the tool blank 11 is provided in a laser machining device 14, which is shown in the central representation of FIG 1 is shown only schematically for reasons of clarity. The laser processing device 14 has an optics module 15, an incident laser beam in the embodiment shown 1 divided into two partial beams 17, 18 and directed in the direction of the top surface 13 of the tool blank 11 to be structured as the tool surface 13. Depending on the application, up to nine laser beams can be used as partial beams. In the exemplary embodiment shown, pulsed laser radiation with pulse durations of 1 ps, ie ultra-short pulses, and with a pulse energy of 100 μJ is used. The two partial beams 17 , 18 directed in the direction of the tool blank 11 are aligned at a finite angle to one another in such a way that the partial beams 17 , 18 interfere with one another in an interference region 19 . The tool blank 11 is arranged in the laser processing device 14 in such a way that the interference area 19 is essentially on the top surface 13 of the tool blank 11 is arranged as a work surface. The interference pattern formed by the interfering partial beams 17, 18 is essentially dependent on the angle enclosed by the partial beams 17, 18, their polarization and the wavelength of the laser radiation used, so that the interference pattern can be adapted as required by changing these parameters. The top surface 13 of the tool blank 11 is structured by the impinging, mutually interfering partial beams 17, 18, with the structuring essentially corresponding to the intensity maxima of the interference pattern. Through the use of ultra-short pulsed laser radiation, the tool 10 is structured, and thus its production, essentially purely ablatively, i.e. without heat being introduced into the top surface 13 of the tool blank 11, since the pulse duration of the laser radiation is so short that there is no thermal interaction of the laser radiation takes place with the material of the tool blank 11. In this respect, this type of processing is also referred to as cold ablation. As a result, comparatively fine structural patterns in the micro and/or nanoscale range can be realized while at the same time avoiding thermal damage to the tool. Due to the partial beams 17, 18 interfering with one another, topographical structures are formed in the region of interference 19, so that a structuring of the top surface 13 of the tool blank 11 is produced. In the exemplary embodiment shown, 50 pulses are superimposed for structuring.

If structuring of the tool blank 11 beyond the interference area 19 of the partial beams 17, 18 is desired, the tool blank 11 can be moved relative to the interference area 19, which includes movements in translation and/or rotation and through the in 1 arrows shown in gray. For this purpose, the laser processing device 14 is designed such that the interference area 19 of the partial beams 17, 18, which in this respect corresponds to a focus area, is movable relative to the top surface 13 of the tool blank 11 to be structured. This is done, for example, by deflecting the two partial beams 17, 18 by means of mirrors controlled by servomotors in the sense of F-Theta optics (in 1 Not shown). As an alternative or in addition to this, the tool blank 11 can, for example, be replaced by in 1 linear guides, not shown, are moved in translation. A rotation of the tool blank 11 relative to the laser processing device, in particular about its axis of extension, is also possible in this way by appropriate guidance. The movement of the interference area 19 relative to the top surface 13 of the tool blank 11 makes it possible to structure the top surface 13 beyond the interference area 19 by successively processing the top surface 13 by means of the interfering partial beams 17, 18, in particular by scanning part or all of the surface.

In the embodiment of 1 the structuring leads to a tool profile 20 of the tool 10, and thus to a surface topography, with linear structural elements 21, which for reasons of clarity are greatly enlarged in the illustration on the right in 1 are shown. The tool profile 20 of the top surface 13 of the tool 10 perpendicular to the direction of extension of the structural elements 21 corresponds approximately to a sinusoidal curve in which depressions 22 and elevations 23 of the same size are formed one after the other at a fixed distance Δd, which is referred to as the lateral period in the sense of the invention are arranged and wherein there is a continuous transition between the depressions 22 and elevations 23; this will be in 1 indicated by solid lines. The lateral period Δd between a depression 22 and a depression 22 adjacent thereto is 10 μm in the exemplary embodiment shown. The ridges 23 are arranged in the same lateral period Δd. This in 1 The tool 10 shown on the right is provided with linear structural elements 21 over its entire surface on its cover surface 13 and is thus finish-machined.

This in 1 The finished tool 10 shown on the right is then used as an embossing tool or embossing die in an in 2 embossing device, not shown, is used and placed opposite the workpiece 12 to be machined, so that the top surface 13 of the tool 10 faces the workpiece 12 . In the embodiment of 2 the workpiece 12 is a sheet of brass (CuZn30). By pressing the tool 10 with the already mentioned tool profile 20 onto the workpiece 12 with a contact pressure of 1,500 MPa, thus along a processing axis 24 arranged perpendicularly to the workpiece surface 13, an at least partial molding of the tool profile 20 onto the workpiece 12 takes place as a plastic deformation , wherein the workpiece 12 is provided with a workpiece profile 25, which at least partially corresponds to the tool profile 20, in particular is at least partially complementary to this. In the illustration on the left 2 the machining axis 24 is illustrated by a large gray arrow. In the exemplary embodiment shown, a full-surface structuring of the workpiece 12 is desired, with the structured top surface 13 of the tool 10 being significantly smaller than the surface of the workpiece 12 to be structured. Therefore, after this processing step, the tool 10 is moved relative to the workpiece 12, whereupon renewed embossing with the specified contact pressure. Subsequently, this process is as long repeated until the workpiece 12 is structured over its entire surface. This process is also referred to as stitching and is illustrated by the small gray arrows in the illustration on the left. The finished structured workpiece 12 is in 2 shown on the right, from which it can be seen that the workpiece profile 25 is at least partially complementary to the tool profile 20 in that the workpiece profile 25 has indentations 22 which are arranged in the same lateral period Δd as the indentations 22 of the tool profile 20.

3 shows another possibility for the production of a tool 10 with a tool profile 20, which differs from that of the embodiment of FIG 1 differs. For this purpose, the tool 10 as a tool blank 11 by means of the laser processing device 14 is initially similar to the embodiment of FIG 1 provided on its top surface 13 over the entire surface with a tool profile 20 with linear structural elements 21 as first depressions 22, so that in this regard reference is made to the above statements to avoid repetition. In contrast to the embodiment of 1 the pulse energy of the laser radiation is 80 µJ and 20 individual pulses are superimposed for structuring. The first tool profile 20 of the third representation of FIG 3 qualitatively similar to the tool profile 20 according to 1 , but in contrast to this, it has a smaller lateral period Δd of 6 µm. After this first structuring, the tool 10 in the transition from the in 3 third representation rotated by 90 ° to the fourth representation about its axis of extension A and again provided in the laser processing device 14, so that a further, full-surface structuring of the top surface 13 is then carried out with the same parameters of the first structuring.

As a result, the in 3 Tool 10 shown on the right has a tool profile 20 with a columnar structure with elevations 23, which are arranged one behind the other in a first direction R ₁ with a first lateral period Δd of 6 μm, and also in a second direction R ₂ , which is perpendicular to the first Direction R ₁ is arranged, are also arranged with a second lateral period Δd of 6 microns one behind the other. Since two adjacent elevations 23 of the tool profile 20 are each separated by a depression 22, the tool profile 20 has first depressions 22 along the first direction _R1 , which are arranged in the first lateral period Δd, and second depressions 22 along the second direction R ₂ arranged in the second lateral period Δd, where in 3 only one lateral period Δd is drawn. The area of the second indentations 22 overlaps the area of the first indentations 22 and the first indentations and the second indentations 22 are produced in separate work steps.

This in 3 The tool 10 shown on the right is used as an embossing stamp in accordance with the workpiece 12 to be machined 4 placed opposite, with the top surface 13 facing the workpiece 12. The machining of the workpiece 12 by the tool 10 takes place by means of a contact pressure of 1,200 MPa along the machining axis 24, so that the columnar tool profile 20 is shaped partially complementary to the workpiece 12, with the result that the workpiece 12 has a workpiece profile 25 with indentations 22 , which, similar to the elevations 23 of the tool 10, are arranged one behind the other in two mutually perpendicular directions R ₁ , R ₂ , each with a lateral period Δd of 6 μm. The full-surface machining of the workpiece 12 takes place as already in connection with 2 described in terms of the stitching, which is indicated by the gray arrows in the left illustration of the 4 is clarified. The right representation of 4 shows the workpiece 12 machined over the entire surface with the tool 10 with the workpiece profile 25 already mentioned.

In the embodiment of 5 the structuring of the tool 10 takes place as a tool blank 11 similar to the embodiment of FIG 3 in two processing steps. First, the cylindrical tool blank 11 made of a tungsten carbide-cobalt hard metal (WC-Co) is provided in the laser processing device 14, which structures the top surface 13 of the tool blank 11 with a first group of depressions 22 in a first processing step. This first processing step is carried out by laser radiation with a pulse duration of 100 fs and a pulse energy of 20 μJ, with three partial beams 17, 18, 26 interfering with one another and ten individual pulses being superimposed. Thereafter, the laser processing device 14 is moved relative to the tool blank 11 in such a way that structuring takes place again until the entire top surface 13 of the tool blank 11 is structured and that in the central representation of FIG 5 shown tool profile 20 is formed. Due to the structuring parameters mentioned, after the structuring of the tool 10, the tool profile 20 has a periodic arrangement of indentations 22, which are also called sinks, with the tool profile 20 having three axes along the top surface 13 of the tool 10, along which the indentations 22 in the are arranged in each case with the same lateral period Δd, the lateral periods Δd of the recesses 22 each being 1 μm. For the purposes of the invention, this arrangement of depressions 22 is also referred to as a hexagonal arrangement. The fully structured tool 10 after the first step is shown in the center of FIG 5 shown where For reasons of clarity, the dimensions of the depressions 22 are not shown to scale but are greatly enlarged.

In a subsequent work step, the tool profile 20 is provided with a further structuring, the area of which overlaps the area of the first structuring. For this purpose, the parameters of the laser processing device 14 are changed so that the second structuring takes place by means of laser radiation with a pulse duration of 100 fs, a pulse energy of 30 μJ and by two laser beams 17, 18 interfering with one another, with the structuring taking place by means of a superimposition of ten pulses, before the laser processing device 14 is moved relative to the tool 10 in the manner already mentioned in order to structure the tool 10 over the entire surface. The second structuring of the tool causes linear structural elements 21 to be formed as depressions 22, which are arranged one behind the other in a lateral period Δd of 2 μm. By superimposing the first structuring with the hexagonally arranged depressions 22 in a - first - lateral period Δd of 1 µm with the second structuring with linear structural elements 21 in a - second - lateral period of 2 µm, the tool profile 20 has a periodic, but at the same time also hierarchical structuring, which is shown in the right-hand representation of the 5 is shown, and which has the linear depressions 22 according to the second structuring as the dominant element, with the hexagonal arrangement of the depressions 22 according to the first structuring having a smaller lateral period Δd compared to the second structuring in the areas not processed as part of the second structuring is trained.

After the tool profile 20 with the hierarchical structure according to the right representation of 5 is provided, the tool 10 is placed opposite a sheet of brass (CuZn30) to be embossed as the workpiece 12 . The workpiece 12 is then subjected to the tool 10 with a contact pressure of 3,500 MPa along the processing axis 24, with the tool 10 being vibrated as an embossing die with a frequency in the ultrasonic range in order to optimize the molding process. This results in a complete molding of the tool profile 20 onto the workpiece 12 , which thus has a workpiece profile 25 that is complementary to the tool profile 20 . Due to the smaller surface of the tool 10 compared to the surface of the workpiece 12, the full-surface structuring of the workpiece 12 takes place by successively moving the tool 10 relative to the workpiece 12 in the sense of the stitching already mentioned, which is shown in the left-hand representation of the 6 represented by the gray arrows. The finished, fully structured workpiece 12 is in 6 shown on the right, the workpiece profile 25 being designed to complement the tool profile 20, as already mentioned.

7 shows a further embodiment of the method for producing the tool 10 by structuring a cylindrical tool blank 11 made of a tungsten carbide-cobalt hard metal (WC-Co), in which this is provided in the laser processing device 14 similar to the previous exemplary embodiments. Structuring is carried out using linearly polarized laser radiation with a pulse duration of 5 ps and a pulse energy of 50 μJ, with 200 pulses being superimposed for structuring. According to the illustration on the left 7 shows that the structuring is carried out by means of two mutually interfering partial beams 17, 18, the linear polarization P of the partial beams 17, 18 being selected in each case so that the plane of polarization is arranged parallel to the top surface 13 of the tool blank 11 to be structured. Due to the structuring of the tool blank 11, the tool profile 20 has sinusoidal, linear structural elements 21 as a group of depressions 22, which are arranged one behind the other in a lateral period Δd of 6 μm, similar to the exemplary embodiment in FIG 1 .

In the embodiment of 7 This - primary - structuring is superimposed by a further - secondary - structuring, which forms due to the polarization of the mutually interfering partial beams 17, 18. This secondary structuring occurs due to the above-described linear polarization of the partial beams 17, 18 and causes the additional generation of linear structural elements 21 as a further group of depressions 22, which have structural sizes, in particular a lateral period Δd, which is approximately at most the Wavelength corresponds to the laser radiation used. The depressions 22 of the secondary structuring are essentially arranged at an angle of 0° relative to the linear polarization of the partial beams 17, 18 and at an angle of 90° relative to the depressions 22 of the primary structuring. The directions of extent of the linear structure elements 21 of the secondary structuring are therefore arranged essentially perpendicular to the polarization of the partial beams 17 , 18 . The production of the first group of depressions 22 as primary structuring and the second group of depressions 22 takes place in a single step by the already mentioned superimposition of 200 pulses and due to the polarization of the partial beams 17, 18. The tool 10 is in the manner already mentioned fully structured; the full-surface structured tool 10 is shown in the right illustration of FIG 7 shown.

With the according 7 manufactured tool 10 is then shown in accordance with the left representation of 8th a sheet of brass (CuZn30) is machined as workpiece 12 by pressing tool 10 as an embossing stamp onto workpiece 12 with a contact pressure of 2,000 MPa along machining axis 24, with tool 10 being used at frequencies in the ultrasonic range along the machining axis at the same time 24 is vibrated to optimize the molding process. As a result, tool profile 20 is not molded onto workpiece profile 25 over its entire height, but only partially as a structure complementary thereto, workpiece profile 25 being the primary structuring with the linear structural elements 21 arranged one behind the other in a lateral period Δd of 6 µm and also the herewith has superimposed secondary structuring with the linear structural elements 21 arranged perpendicularly to the first structuring and having dimensions which are essentially smaller than the wavelength of the laser radiation. As far as the applicant is aware, the generation of this - superimposed - structuring as a workpiece profile 25 on brass (CuZn30) is not possible with direct processing using laser radiation, but only with the molding process described above, since the latter does not involve any melting dynamics when generating the structuring on the workpiece profile . The machining of the workpiece 12, and thus the generation of the superimposed structuring on the workpiece profile 25, takes place with a single pressing or embossing step. The full-surface structuring of the workpiece 12 then takes place in terms of stitching, as has already been described. The fully structured workpiece 12 is in 8th shown on the right.

9 shows another embodiment in which the tool blank 11 analogous to the embodiment of FIG 7 is structured, in particular also with laser radiation with a pulse duration of 5 ps and a pulse energy of 50 μJ. The structuring is carried out by means of two mutually interfering partial beams 17, 18, with the linear polarization P of the partial beams 17, 18 being selected in such a way that the polarization axes of the partial beams 17, 18 again each have an angle of 0° relative to the top surface 13 of the include tool blank 11; the polarization axes of the partial beams 17, 18 are therefore parallel to the top surface 13 of the tool blank 11 and also perpendicular to the polarization axes of the partial beams 17, 18 in the embodiment of FIG 7 aligned. Analogous to the embodiment of 7 the structuring of the tool blank 11 takes place by superimposing 200 laser pulses. The fully structured tool 10 is in 9 shown on the right, its tool profile 20 having a primary structuring with a first group of sinusoidal, linear structural elements 21 as depressions 22, which are arranged in a lateral period Δd of 6 μm and in this respect the primary structuring of the exemplary embodiment 7 is equivalent to. Due to the linear polarization P of the partial beams 17, 18, the tool profile 20 has a secondary structuring with linear structural elements 21 which overlay the primary structure and which are designed in the order of at most the wavelength used. Due to the alignment of the linear polarization vectors P of the partial beams 17, 18, the secondary structuring with the linear structural elements 21 as depressions 22 is parallel to the direction of extension of the primary structuring and thus perpendicular to the secondary structuring of the exemplary embodiment 7 arranged. The structuring of the tool blank 11, including the primary and secondary structuring, takes place in a single work step. 9 shows the fully structured tool 10 on the right.

With the according 9 manufactured tool 10 is in accordance with 10 the workpiece 12, here as an example a sheet of brass (CuZn30) is machined and structured, with the structuring being carried out by a contact pressure of the tool 10 on the workpiece of 2,000 MPa along the processing axis 24 and a simultaneous vibration of the tool 10 along the processing axis 24 with a vibration frequency in the ultrasonic range. This results in a partial molding of the tool profile 20 on the workpiece profile 25, the workpiece profile 25 having a structure designed to complement the tool profile 20, so that in this respect the above description of the tool profile 20 according to 9 is referenced. The full-surface processing of the workpiece 12 takes place in the way of the stitching already described, which is indicated by the gray arrows in the right-hand representation of FIG 10 is shown. The fully machined workpiece 12 is in 10 shown on the right.

The 11 until 14 show another configuration. According to 11 here is a tool blank 11 made of a tungsten carbide-cobalt hard metal (WC-Co) analogous to the embodiment of FIG 1 provided with a tool profile 20 with linear structural elements 21 as depressions 22 with a lateral period Δd of 10 μm. In a first processing step, the tool 10 produced in this way is used to structure a sheet of brass (CuZn30) as a workpiece 12 over its entire surface, as has already been done in connection with FIG 2 is described, which differs from the embodiment of 2 now a contact pressure of 1,000 MPa ent along the machining axis 24 is used. The fully structured workpiece 12 is in 12 shown on the right.

After the full-surface structuring of the workpiece 12, the tool 10 according to 13 rotated by 90° about its axis of extension A in such a way that the linear structural elements 21 are now aligned perpendicular to the structural elements 21 of the workpiece 12 . This is in the right representation of the 13 shown. In this alignment, in a second processing step, the tool 10 is subjected to a contact pressure of 1,000 MPa along the axis of extension 24 on the workpiece 12, so that a superimposed structuring of the workpiece 12 is formed as a workpiece profile 25, which can be seen as a checkerboard pattern in the exemplary embodiment shown. 14 shows on the left the workpiece 12 which has not yet been completely structured in the second processing step. The full-area structuring of the workpiece 12 is effected by the stitching already explained; the fully structured workpiece 12 is in 14 shown on the right. The - superimposed - structuring of the workpiece profile 25 is therefore obtained by a single tool 10 with a single, primary structuring in two successive processing steps, the tool 10 being rotated by 90° about its axis of extension A between the processing steps.

The 15 and 16 show a further exemplary embodiment in which a tool 10 structured over the entire surface according to FIG 1 is assumed and that in the left representation of 15 is shown. The tool profile 20 has linear structural elements 21 as indentations 22 with a depth of 10 μm compared to the unstructured area of the top surface 13, the indentations 22 being arranged one behind the other in a lateral period Δd of 10 μm. A sheet of brass (CuZn30) is applied as a workpiece 12 with the tool 10 produced in this respect with a first contact pressure of 1,500 MPa along the processing axis 24, which is shown in the central representation of FIG 15 will be shown. This results in an incomplete molding of the tool profile 20 on the workpiece profile 25, only half of the structural depth of the tool profile 20, which is referred to as the machining depth in the context of the invention, being molded. The processing depth therefore does not correspond to the full depth of the depressions 22 of the tool profile 20. As a result, the workpiece profile 25 has comparatively sharp-edged plateaus with a width of 5 μm each, which are separated from one another by trenches as depressions 5 μm wide and 5 μm deep. According to the applicant's knowledge, such a workpiece profile 25 cannot be produced by direct structuring by means of laser radiation, since the melting dynamics that occur in this way lead to a rounding of the workpiece profile and impair it. The full-surface structuring of the workpiece 12 takes place by means of stitching; the fully structured workpiece 12 is in 15 shown on the right.

16 illustrates a further embodiment of the processing of a sheet of brass (CuZn30) as a workpiece 12 with the in 15 Workpiece 12 shown on the left, wherein the structuring of the workpiece 12 with a compared with the method of 15 greater contact pressure of 3,500 MPa along the processing axis 24 and a simultaneous vibration of the tool 10 as an embossing stamp with frequencies in the ultrasonic range along the processing axis 24 takes place. In this way, a complete molding of the tool profile 20 on the workpiece profile 25 is obtained, so that the complete structural depth of 10 μm of the tool profile 20 is molded. The processing depth of the procedure according to 16 is therefore, due to the greater contact pressure, greater than the processing depth of the method 15 . As a result, the workpiece profile 25 has a structure with sinusoidal, linear structure elements 21 which have a depth of 10 μm and a lateral period Δd of 10 μm. The workpiece profile 25 is in this respect corresponding, in particular complementary, to the tool profile 20. The full-surface structuring of the workpiece 12 takes place by means of stitching and is the result in 16 shown on the right.

The 17 and 18 illustrate a further embodiment of the method for machining a workpiece 12, which is a sheet of brass (CuZn30) by way of example. The tool 10 used for this is in 17 arranged on the left and has a tool profile 20 with an all-over structuring with columnar elevations 23 , a depression 22 being formed as a structural element 21 between two adjacent elevations 23 . The indentations 22 themselves are periodically arranged one behind the other in two mutually perpendicular directions. In this respect, the tool profile corresponds to that of the exemplary embodiment according to FIG 3 . Quantitatively and in contrast to the embodiment of 3 the depressions 23 each have a depth of 10 μm compared to the unstructured area of the workpiece 10 and are arranged one behind the other in lateral periods Δd of 10 μm each.

The tool 10 is in accordance with the central representation of 17 pressed as an embossing die with a—comparatively low—contact pressure of 1,200 MPa along the machining axis 24 onto the workpiece 12, so that, as already described, only a partial impression of the tool pro fils 20 on the workpiece profile 25 takes place. In the present exemplary embodiment, the tool profile 20 is formed only up to half of the structure geometry of 10 μm, which in this respect corresponds to the machining depth. This results in the workpiece profile 25 having sharp-edged indentations 22 with a diameter of 5 μm, the indentations 22 being arranged in a cubic periodic pattern. As far as the applicant is aware, workpiece profiles 22 of this type, in particular their sharp-edged depressions 22, cannot be produced by means of direct laser structuring. The full-area processing of the workpiece 12 takes place by stitching, as has already been described. The fully machined workpiece 12 is in 17 shown on the right.

In 18 another sheet of brass (CuZn30) as workpiece 12 with the embossing die as tool 10 according to FIG 17 edited and structured, being in contrast to 17 a comparatively large contact pressure of 3,500 MPa along the processing axis 24 with an additional vibration of the tool 10 during the embossing process with frequencies in the ultrasonic range is used in order to obtain as complete an impression as possible of the tool profile 20 on the workpiece profile 25. In the present exemplary embodiment, the molding of the tool profile 20 takes place up to the complete structure depth of 10 µm, so that the result is that the tool profile 25 has a columnar topography, the indentations 22 of which have a depth of 10 µm and in two mutually perpendicular, lateral periods Δd of 10 µm are arranged one behind the other. The workpiece profile 25 is thus designed to be complementary to the tool profile 20 . The full-surface processing of the workpiece 12 takes place by means of stitching, as has already been described and in 18 is indicated by the gray arrows in the illustration on the left. The fully machined workpiece 12 is in 18 shown on the right.

Claims (20)

Tool (10), in particular a stamping or forming tool, structured according to a method for producing a tool (10) for machining a workpiece (12), in particular a stamping or forming tool, in which a metallic tool blank (11) is provided in a laser processing device (14) and the laser processing device (14) structures the tool blank (11) on a tool surface (13) by means of interference of at least two laser beams (17, 18, 26), wherein the at least two laser beams (17, 18, 26) at least at times have pulse durations of at most 15 ps and a tool profile (20) with at least one depression (22) being produced by the structuring on the tool surface (13). tool (10) after claim 1 , characterized in that the at least one depression (22) is produced with a dimension, in particular with a depth relative to an unstructured area of the tool surface (13), between 10 nm and 50 µm, in particular between 100 nm and 15 µm. Tool (10) according to one of Claims 1 or 2 , characterized in that at least two depressions (22) are produced with essentially identical dimensions, in particular with essentially identical depths. Tool (10) according to one of Claims 1 until 3 , characterized in that at least one group of depressions (22) is produced in a periodic pattern on the tool surface (13). tool (10) after claim 4 , characterized in that the group of depressions (22) in the periodic pattern on the tool surface (13) with a lateral period (Δd) between 10 nm and 50 µm, in particular between 100 nm and 15 µm, in at least one direction along the Tool surface (13) is generated. Tool (10) according to one of Claims 1 until 5 , characterized in that at least one group of depressions (22) is produced on the tool surface (13) with a linear course and/or with a rectangular, preferably square basic shape and/or with a circular basic shape. Tool (10) according to one of Claims 1 until 6 , characterized in that at least two first depressions (22), in particular a first group of depressions (22), with a first lateral period (Δd) between 10 nm and 50 µm, in particular between 100 nm and 15 µm, are produced and at least two second depressions (22), in particular a second group of depressions (22), are produced with a second lateral period (Δd), the second lateral period (Δd) in particular being smaller than the first lateral period (Δd). tool (10) after claim 7 , characterized in that the area of the second depressions (22), in particular the second group of depressions (22), the area of the first depressions (22), in particular the first group of depressions (22) at least partially overlaps. Tool (10) according to one of Claims 7 or 8th , characterized in that the production of the first depressions (22), in particular the first group of depressions (22), and the production of the second depressions (22), in particular the second group of depressions (22), in a single work step or in separate work steps. tool (10) after claim 9 , characterized in that the first depressions (22), in particular the first group of depressions (22), are generated by means of interference of the at least two laser beams (17, 18, 26), the second depressions (22), in particular the second group of indentations (22), by means of interference of at least two laser beams (17, 18, 26) and/or by means of a single laser beam (17, 18, 26). Tool (10) according to one of Claims 1 until 10 , characterized in that the tool blank (11) before and / or the tool (10) is coated after the structuring. tool (10) after claim 11 , characterized in that the tool (10) has at least one component made of a hard metal, which has a plurality of hard material particles and a binder matrix, and / or has at least one component made of a thermally treated tool steel. Tool (10) according to one of Claims 11 or 12 , characterized in that the tool (10) at least in some areas on the tool surface (13) has a hard material layer, preferably a carbon layer, most preferably a tetrahedral, hydrogen-free carbon layer. Workpiece (12) machined with a tool (10) according to one of Claims 1 until 13 , the workpiece (12) being plastically deformed at least in regions by means of the tool (10) and being provided with a workpiece profile (25) which corresponds at least in regions to the tool profile (20). Workpiece (12) after Claim 14 , characterized in that the workpiece (12) is plastically deformed by means of the tool (10) in at least two processing steps, wherein in a first processing step the tool (10) plastically deforms the workpiece (12) along a processing axis (24) with a first processing depth deformed and wherein in a second machining step the tool (10) plastically deforms the workpiece (12) along the machining axis (24) with a second machining depth and in particular wherein the first machining depth differs from the second machining depth. Workpiece (12) after claim 15 , characterized in that the first machining step is carried out with a first tool (10) and the second machining step with a second tool (10), the first tool (10) and/or the second tool (10) being carried out according to one of Claims 1 until 13 are designed. Workpiece (12) after Claim 16 , characterized in that the second tool (10) has a periodic structure with a lateral period (Δd) which is in particular smaller than the lateral period (Δd) of the periodic structure of the first tool (10). Workpiece (12) according to one of Claims 15 until 17 , characterized in that the press-in pressure of a processing step differs from the press-in pressure of another processing step. Workpiece (12) according to one of Claims 14 until 18 , characterized in that the workpiece (10) is plastically deformed by means of a vibrating movement of the tool (10), in particular along the machining axis (24). Workpiece (12) according to one of Claims 14 until 19 , characterized in that the workpiece (12) is machined by means of the tool (10) at a maximum temperature of 1200° C., in particular free of an external heat input.

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