EP1985463A1 - Method for manufacturing an embossing tool - Google Patents

Abstract

The method involves providing an embossing die with two opposite embossing molds, which define a space for accommodating a metal plate, where a surface of the mold has a structured embossing region (9) with alternative depressions (10) and raisings (11). The depressions are designed as groove-shaped depressions such that the depressions lie on virtually straight lines, which run parallely over the entire elongation of the structured embossing region. The depressions are produced by grinding e.g. profile grinding, milling e.g. roll milling, laser radiation and ultrasonic discharging.

Description

The invention relates to a method for producing an embossing tool for producing at least one area provided with a surface structuring on at least one surface of a metal plate. The embossing tool has two opposing embossing molds defining a space between them for receiving the metal plate. At least one of the embossing molds has on its surface facing the other embossing mold at least one structured embossing region, the structuring of which is complementary to the surface structuring to be produced and has mutually alternating recesses and elevations. If correspondingly embossed embossed areas are embossed in a metal plate, a surface structuring is produced in the metal plate, which likewise has mutually alternating depressions and elevations, the depressions in the metal plate corresponding to the elevations in the embossing region of the embossing mold and elevations are formed in the metal plate where in Embossing area of the embossing mold depressions are present. Such surface structuring in metal plates are used, for example, to achieve an increase in surface area in the metal plate. In areas of enlarged surface of the metal plate, for example, the adhesion of certain materials such as plastic coatings on the metal surface can be improved. In addition, by the surface structuring a thickening of the metal plate material can be achieved without the need for additional material must be applied to the metal plate. For such surface structuring of metal plates, there are a variety of applications, and correspondingly diverse are the design options with respect to the shape and extent of surface structuring on the metal plate and the choice of materials.

There is therefore a need for an embossing tool with which not only various types of metal plates are processed, but also various types of surface structuring can be produced with structures, sizes and shapes adapted to the respective requirements. So the depressions and elevations of the embossing area should be made of a hard and resistant material so as to be able to be embossed in hard metal plates on the one hand and also to show the lowest possible wear during embossing. The shape of the recesses and elevations should be as variable as possible in order to make the type of surface structuring in the embossed metal plate as varied as possible, but on the other hand, the structuring of the embossed area should also be able to be produced in a simple and cost-effective manner. In addition, the embossed areas should be varied in their shape in a simple manner and can be adapted quickly to the conditions encountered, so that the required embossing tools can be produced quickly and inexpensively.

The object of the invention is accordingly to provide a method for producing a stamping tool, which meets the above requirements.

The solution of the problem is achieved with the method according to claim 1. Preferred variants of the method can be found in the dependent claims.

The invention accordingly relates to a method for producing an embossing tool for producing at least one area provided with a surface structuring on at least one surface of a metal plate. The embossing tool has two opposing embossing molds defining a space between them for receiving the metal plate. At least one of the embossing molds has, on its surface facing the other embossing mold, at least one structured embossing region, which is complementary to the surface structuring to be produced in the metal plate and has depressions and elevations which alternate with one another. According to the invention, the depressions are produced in such a way that they are groove-shaped and lie on at least one family of substantially straight parallel virtual lines extending over the entire extent of the structured embossing region.

Generating groove-shaped depressions on at least one family of virtual straight lines extending substantially parallel to one another has the advantage that the depressions can be generated by machine over the entire structured embossing region in a simple manner and in a few process steps. A substantially parallel course is to be understood here as a deviation from the parallelism of a maximum of 5 ° and in particular a maximum of 2 °. The straight lines followed by the depressions run continuously over the entire extent of the structured embossing area. This means that pits and elevations over the entire area occupied by the embossing area is very regularly distributed, which makes the production of this embossing area much easier. Between the recesses produced remain surveys, which are limited by the wells. Overall, surveys and recesses alternate in the embossing area.

The depressions are expediently produced by the following methods: grinding, in particular profile grinding, milling, in particular rolling, disk, shank or form milling, erosion, laser radiation, ultrasonic ablation or engraving. In principle, any erosion process is suitable for producing the depressions. However, the above-mentioned methods are particularly suitable for producing the groove-shaped recesses. For reasons of process economy, it is particularly preferred if all depressions are produced by one and the same method, that is to say exclusively by profile grinding. However, it is also conceivable to use different methods in combination with each other. With the above-mentioned methods, recesses and emboss areas structured therewith can be produced even in hardened tool plates, for example hardened steel. This in turn means that even hard metal plates such as spring steel plates can be embossed and patterned with the embossing tool according to the invention. Alternatively, it is of course also possible to produce the structured embossed area in an uncured, soft tool plate by introducing the depressions and then to harden the tool plate with the at least one structured embossed area.

The shapes of the depressions and elevations of the structured embossing area can be varied in a variety of ways. The shape, size and position of the depressions depend on the shape, size and position of the remaining elevations of the embossing area. In particular, the depth at which the recesses are recessed into the embossing area, the cross-sectional shape of the recesses in a direction perpendicular to their longitudinal direction, the width of the recesses and their distance from each other can be suitably varied. In order to produce the corresponding cross-sectional shape of the depressions, it is expedient to use a tool for producing the depressions, which is provided with at least one profile region whose cross-sectional shape corresponds to the cross-sectional shape of the depressions in a direction perpendicular to their longitudinal extent. The profile region of the tool thus digs into the tool plate during the production of the depressions, where it generates a depression having a shape which substantially corresponds to the shape of the profile region. In this case, it is basically possible to create one recess after another by first guiding the tool with its profile region along a first of the virtual straight lines over the embossing region of the tool plate and then laterally staggered along another one of the parallel virtual straight lines to create another pit, and so on until all pits of the patterned imprint area are created. However, it is more effective if the tool has a plurality of profile regions arranged parallel to one another, so that a plurality of depressions are produced simultaneously in the embossing region. In this case, the profile areas do not necessarily have the same distance from each other, as should later have directly adjacent recesses in the structured embossing area. Especially with very closely adjacent recesses, it makes more sense if the profile areas of the tool have a distance from each other, which corresponds to a multiple of the distance between the recesses to be generated. Between the depressions initially produced in the structured embossing region, there is still an unstructured region which is gradually structured by lateral displacement of the tool and subsequent production of further depressions until the entire embossing region is provided with the desired structuring.

It is particularly easy to automate the introduction of the depressions when the individual depressions are generated along virtual straight lines that are equidistant from each other. However, this is not essential. It is equally possible for the virtual straight lines along which the depressions of the structured embossing region extend to have mutually different spacings, at least in a partial region of the embossing region. For example, in one or more regions of the embossing region, the depressions can be introduced at a greater distance from one another, so that wider elevations remain in this region, while in other regions the depressions are closer together and thus narrower elevations are produced. In this way, the stability of the remaining surveys can be adjusted specifically. For example, elevations which are more easily plastically deformable than wider elevations can be obtained by closely spaced recesses or wide depressions between which only narrow elevations remain. In addition, it is possible, for example, to make the depressions upward, toward the surface of the tool plate, so wide that adjacent depressions in the area of the surface overlap one another. In this way, elevations are obtained whose highest point is lower than the initial surface of the tool plate, in which the recesses were introduced. By appropriate variation of the recesses, it is possible to obtain surveys on the embossing area, which vary in height. In addition, variations in the shape of the elevations by varying the shape of the introduced wells are possible. The variation of the shape of the pits is, as mentioned, easiest by variation the profile range of the tool is possible with which the recesses are introduced into the embossing area.

Below are some preferred tools are called, with which the wells can be produced particularly well in the structured embossing area. A preferred tool is a profile grinding tool which has a grinding wheel, on whose outer circumference at least one profile area is formed. The grinding wheel is rotated about an axis perpendicular to the disk surface. The profile grinding tool is guided in a direction perpendicular to the axial direction along the virtual straight lines over the surface to be structured. In this case, the at least one profile region digs into the tool plate on the outer circumference of the grinding wheel. The next recess is created by axially setting the profile grinding tool sideways onto and following the next virtual line until the second recess is recessed over the entire emboss area to be patterned. These steps are repeated until all recesses provided for the embossing area have been produced. When using a grinding wheel, which has a plurality of mutually parallel profile regions on the outer circumference, the method can be accelerated.

In a manner similar to the grinding tools, it is also possible to use milling tools which have at least one milling disk, on the outer circumference of which again a profile area is formed. Instead of a milling tool with milling discs and a milling cutter can be used, which has the shape of a roller, on the outer circumference circumferentially several mutually parallel profile regions are present. In order to obtain depressions lying on parallel virtual straight lines by advancing the milling cutter in a direction perpendicular to the axial direction, the profile portions are arranged on the outer peripheral surface so as to circulate along a line on which the outer circumferential surface extends from a direction perpendicular to the axial direction Cylinder lying plane is cut.

While in the aforementioned methods, the rotational axis of the tool is held substantially parallel to the surface of the tool plate to be structured, the axis of rotation is arranged in the following method substantially perpendicular or oblique to the surface of the region to be machined. In the case of an end mill, the milling tool is usually applied obliquely to the surface to be treated, and the recess is buried with the front end edge region of the milling drum in the surface, this edge region is preferably formed here as a profile area to the generated depression a desired To give profile. In shape milling, the profile area is in the tip area of the bur or bur educated. To generate the depressions, the stylus is rotated about its longitudinal axis and simultaneously advanced along a virtual straight line. Similarly, instead of a form milling tool also a molding pin can be used for grinding. For generating the depressions, in addition, ultrasound-supported ablation tools are particularly suitable, the tip of which has a profile area. Such ablation methods are also known as "ultrasonic" methods. Suitable tools are available, for example, from Sauer GmbH, D-55758 Stipshausen, see also www.gildemeister.com.

Another possibility for producing the depressions in the structured embossing region is the die sinking by means of a suitably shaped electrode. Die sinking has the advantage that very many and preferably all pits of the structured stamping area can be produced at once. The erosion electrode is thus preferably located over the entire embossing area to be structured on the tool surface. In the electrode material, which preferably consists of copper or graphite, elevations are present which correspond to the depressions of the embossing area to be produced. These elevations must first be generated in the electrode surface. This is particularly preferably done by means of one of the methods described above, that is, for example, by milling or grinding the electrode material in such a way that the required elevations of the electrode material remain stationary. The process may initially appear somewhat cumbersome, since so to speak the negative has to be produced by the negative, however, the additional effort in the manufacture of the electrode is compensated by the fact that in the production of the embossing tool all depressions of the embossing area can be produced in one step.

If the depressions in the method according to the invention are produced in such a way that they lie on only one family of substantially straight parallel virtual lines extending over the entire extent of the structured embossing region, an embossing region is obtained in which corrugations extending parallel to one another are formed with raised ribs lying therebetween , The shape and size of the recesses and the intervening ribs can be varied in the manner already described. Larger variations in the structure of the embossed area, however, arise when the depressions run on more than a family of parallel virtual straight lines. However, this increases the effort in the production of the embossing area, as additional wells must be created. The depressions then run along at least two intersecting groups of virtual straight lines. It is preferred in this case if the recesses are produced in such a way that they extend at an angle of 30 to 150 °, preferably 45 to 135 ° and particularly preferably 80 to 100 °. In a In a very particularly preferred variant of the method, the depressions are produced in such a way that two sets of intersecting virtual straight lines run at right angles to one another. In all cases, net-like structures of the recesses result with elevations lying in between, which have a rectangular or square base area in the case of a pair of lines arranged at right angles to one another.

It is also possible to create the pits so that they run on more than two sets of intersecting virtual straight lines. However, because of the increasing expense of creating the pits, it is not preferable to use more than three sets of virtual straight lines as the pattern of patterns for the pits. If the depressions lie on three sets of virtual straight lines, they preferably intersect at an angle of 60 °. The elevations of the structured embossing area accordingly each have the footprint of an isosceles triangle.

As already mentioned several times, there are a large number of variation possibilities with regard to course, size and shape of the depressions with which the properties of the embossing area and finally the properties of the surface structuring in the metal plate to be embossed can be influenced. The depressions of the at least one embossing area of the embossing tool ultimately correspond to elevations of the surface structuring of the embossed metal plate. Accordingly, the cross-sectional shape of the recesses is selected so that the complementary surveys of the surface structure obtained obtained the desired shape. This form is basically arbitrary. However, preferred are cross-sections that are trapezoidal, triangular, rounded or rectangular. The bumps that remain after the recesses have been recessed in the embossing area, preferably have a dome-shaped, rectangular, triangular or trapezoidal cross-section. Since reticulated depressions are preferably produced in the method according to the invention - ie depressions which run along several intersecting groups of virtual straight lines - such elevations are preferred which have the shape of a polyhedron stump.

The elevations can be varied not only in their shape but also in their height over the embossing area. If there are several embossing areas per embossing form, it is also possible to vary the shape and height of the elevations from embossing area to embossing area. It has already been pointed out that the height of the elevations can already be varied by appropriate design of the depressions during their production. Another possibility of height variation of the elevations is that their height after the creation of the depressions is changed. For example, it is basically possible to initially produce the elevations with greater than the desired height and then to reduce the height of the elevations over the entire embossing area. This can be done, for example, for the purpose of achieving a uniform height of the surveys over the entire embossing area. Instead of the uniform height reduction but also a partial reduction of the height of the surveys is possible. In this way, a height topography can be generated within the structured embossing area of the embossing tool. This topography of the embossing area, in turn, leads to a topography within the surface structuring of the metal plate embossed by the embossing tool.

It has already been pointed out that it is particularly advantageous for the production of the stamping tool that all depressions are located on at least one family of parallel straight lines which extend over the entire stamping area. However, this does not necessarily mean that the embossing area must always have a self-contained and relatively simple structure. The embossing region may for example also be annular and have in its center a region in which no depressions and elevations are present. As well forms with strongly vaulted outer contours or protuberances are possible. It is thus possible for a recess to be interrupted in its longitudinal extension by a recessed area without depressions and elevations (that is to say without a structured area). However, this does not contradict the statement that the depressions are produced in such a way that they lie on at least one family of substantially straight lines extending over the entire extent of the structured embossing region, since these lines are virtual lines. For example, a virtual straight line extends the full width of a structured imprint area, while the indentation following that virtual line is interrupted by an area without structuring, but then continues after the interruption on the same virtual line.

The production of such a structured embossed area is carried out, for example, in such a way that recesses are initially produced in a region which is larger than the required structured embossing area. This larger area is completely covered with pits. In the case of an annular embossing region, for example, depressions are therefore initially generated continuously even in the interior of the annular region and optionally also around its outer contour. Subsequently, those recessed areas which are outside the required embossing area are removed. This can in principle be done in different ways. In one variant, the required embossing area completely from the machined tool plate cut out and used as a separate part in a designated place one of the embossing forms. The separation of the embossing area from the machined tool plate can be done for example by wire erosion or by any other suitable cutting or separation method.
In another variant, the structured area required as an embossing area is retained in the processed tool plate as a raised area, while the surrounding areas are reduced in height. This means that the elevations obtained by burying the recesses outside the embossing area are reduced so much in their height that they can no longer exert any embossing effect on the metal plate to be processed. Particularly preferably, the elevations are completely removed. Thus, only the embossing area provided with recesses and elevations remains as a raised area in the tool plate. The removal of the elevations outside the embossing area can be carried out in any suitable manner. Preferably, the elevations are reduced by grinding or milling in height or completely removed.

The subsequent working out of the required embossing areas from a larger area provided with elevations and depressions tool plate has the advantage that even very complicated embossed areas can be obtained in a simple and cost-effective manner, without this form would have to be considered already in the production of the wells. In addition, it is possible to provide tooling plates with a wide variety of surface textures and to work out those embossing areas as required and to use them in embossing tools. In this way, suitable embossing tools for specific applications are available quickly and easily. The embossing tool itself must not be changed - apart from the replacement of the embossing area. The insertion of separate embossing areas in the embossing molds also makes it possible to use stamping areas of very different structures in a single embossing mold and to adapt the embossing areas very variably to the requirements.

In the simplest embodiment, only a single embossing area is used in one of the embossing molds of the embossing tool, so that a surface structuring is embossed on only one surface of the metal plate to be processed. However, it is preferred to use stamping molds which each have a structured stamping region on their surfaces lying opposite one another. Appropriately, these embossed areas are the same design, but this is not absolutely necessary. In order to ensure that opposing embossed areas have the same shape, it is possible to arrange two structured tool plates opposite one another and to separate the desired embossed areas from both plates in one operation. In the same way, surveys that are not required around the structured embossing areas can be removed on the plates lying opposite one another, even in a common removal step. In opposite embossing regions, it is preferred that the depressions are produced in such a way that the elevations of a stamping region of one of the stamping molds can engage in the depressions of the opposite stamping region of the other stamping mold.

The method according to the invention can be applied to a wide variety of metallic materials for producing the patterned embossed areas. As already mentioned, the method is also suitable for producing structured embossed areas in hardened tool plates, such as, for example, hardened steel. Alternatively, it is possible to insert the recesses in soft, uncured tooling plates and then to harden the structured plates. The material of the tool plates to be structured depends primarily on the intended application. Usually, material thicknesses of 5 to 200 mm, preferably 10 to 80 mm, are sufficient for the expected force loads. Elevations of high height may require thicker plates.

The embossing tool obtained by the method according to the invention is suitable for producing a wide variety of surface structuring in a wide variety of materials and in particular for surface structuring of metal plates such as gasket layers of a flat gasket, in particular a cylinder head gasket, exhaust manifold gasket or flange gasket. Likewise, parts of such metal plates can be embossed, so for example so-called inserts, which are used in recesses of larger plates. By way of example, mention should be made of annular sections which are formed around the passage openings in sealing plates. The embossed structures-and correspondingly the structuring of the stamping area of the embossing tool-can be designed such that they improve the adhesion of plastics (for example for elastomeric sealing elements or surface coatings) on the metallic surface, form thickened areas for supporting adjacent elastic sealing elements, areas with predetermined plastic deformability and / or certain topography or the like.

Figur 1

eine Zwischenstufe bei der Herstellung eines Prägewerkzeugs mittels Schleifen;

Figur 2

ein Zwischenstadium bei der Herstellung eines Prägewerkzeugs mittels Fräsen;

Figur 3 (a)

eine Vorderansicht auf ein Schleifwerkzeug während des Einbringens von Vertiefungen in eine Werkzeugplatte;

Figur 3 (b)

den Bereich O in Figur 3 (a) in einer vergrößerten Darstellung;

Figuren 4 und 5

zwei unterschiedlich ausgebildete Schaftfräser beim Einbringen von Vertiefungen in eine Werkzeugplatte;

Figuren 6 und 7

zwei unterschiedlich ausgebildete Fräswerkzeuge beim Einfräsen von Vertiefungen in eine Werkzeugplatte;

Figur 8

das Einbringen von Vertiefungen in eine Werkzeugplatte mittels Senkerodieren;

Figur 9

das Einbringen von Vertiefungen in eine Werkzeugplatte durch Fräsen mit einem Einschneider;

Figur 10

das Einbringen von Vertiefungen in eine Werkzeugplatte mittels Laserstrahlung;

Figur 11

das ultraschall-unterstützte Einbringen von Vertiefungen in eine Werkzeugplatte;

Figur 12

das Einbringen von Vertiefungen in eine Werkzeugplatte mittels Formschleifen;

Figuren 13 bis 17

Draufsichten auf verschiedene strukturierte Prägebereiche eines Prägewerkzeugs;

Figuren 18 und 19

Draufsichten auf strukturierte Prägebereiche, in denen die Vertiefungen auf zwei sich senkrecht schneidenden Scharen gerader Linien verlaufen;

Figur 20

eine Teilansicht eines Prägewerkzeugs mit zwei jeweils mit Vertiefungen und Erhebungen versehenen Prägeformen, die ineinandergreifen;

Figur 21 (a)

eine Teilansicht eines Prägewerkzeugs, das im Wesentlichen demjenigen der Figur 19 entspricht, wobei jedoch in der unteren Prägeform die Erhebungen unterschiedliche Höhen aufweisen;

Figur 21 (b)

ein Querschnitt durch das Prägewerkzeug gemäß Figur 21 (a) im eingekreisten Bereich;

Figuren 22 (a) bis (d)

verschiedene Verfahrensstadien bei der Herstellung separater Prägebereiche mit Darstellung der unteren und oberen Prägeplatte; und

Figur 23

eine Querschnittsansicht eines Prägewerkzeugs mit zwei Prägeformen und dazwischen eingelegter geprägter Metallplatte.

The invention will be explained in more detail with reference to drawings. The drawings describe only exemplary preferred variants of the present invention, but the invention would not be limited to these examples. In the drawings, like reference numerals designate like parts. The figures are schematic and show:

FIG. 1

an intermediate stage in the production of a stamping tool by means of grinding;

FIG. 2

an intermediate stage in the production of a stamping tool by means of milling;

FIG. 3 (a)

a front view of a grinding tool during the introduction of depressions in a tool plate;

FIG. 3 (b)

the area O in FIG. 3 (a) in an enlarged view;

FIGS. 4 and 5

two differently shaped end mill when introducing recesses in a tool plate;

FIGS. 6 and 7

two differently shaped milling tools when milling recesses in a tool plate;

FIG. 8

the introduction of depressions in a tool plate by means of die sinking;

FIG. 9

the introduction of depressions in a tool plate by milling with a Einschneider;

FIG. 10

the introduction of depressions in a tool plate by means of laser radiation;

FIG. 11

the ultrasound-assisted introduction of depressions into a tool plate;

FIG. 12

the introduction of depressions in a tool plate by means of form grinding;

FIGS. 13 to 17

Top views of various structured embossing areas of a stamping tool;

FIGS. 18 and 19

Plan views of structured embossed areas, in which the recesses extend on two perpendicular intersecting sets of straight lines;

FIG. 20

a partial view of a stamping tool with two each provided with depressions and surveys embossing dies, which engage;

Figure 21 (a)

a partial view of a stamping tool, which is substantially that of FIG. 19 corresponds, but in the lower embossing mold, the elevations have different heights;

FIG. 21 (b)

a cross section through the embossing tool according to Figure 21 (a) in the circled area;

FIGS. 22 (a) to (d)

different process stages in the production of separate embossing areas with representation of the lower and upper embossing plate; and

FIG. 23

a cross-sectional view of an embossing tool with two embossing shapes and intervening embossed metal plate.

FIG. 1 shows an intermediate stage in the production of an embossing tool, namely concretely an intermediate stage in the production of a structured embossing area 9. The embossing area 9 is arranged as a raised area, here for example in rhombic form, on a clamping table 30 shown here only partially. Work table 30 and embossing area 9 expediently consist of metal, for example of hardened stainless steel. The embossing area 9 should be provided with a structuring over its entire surface. The structuring of the embossing region 9 in the present case consists of a multiplicity of mutually parallel linear depressions 10. Shown here is an intermediate stage in which the embossing region 9 is provided approximately halfway, in the image on the left, with depressions 10.

The recesses 10 are recessed in the example shown by grinding in the surface of the embossing region 9. For this purpose, a profile grinding tool WPS is used. This profile grinding tool comprises a profile grinding wheel (S), which is arranged on a rotation axis R and has two profiles P1 and P2, which are arranged parallel and at a distance from one another. The axis of rotation R is rotated by means of a drive device, which is not shown here in detail, whereby the profile grinding wheel S is also rotated. The rotating profile grinding tool WPS is then guided along the arrows X and Y over the region 9 to be structured until the depressions 10 have reached the required depth. Subsequently, the profile grinding tool is displaced laterally in the direction of the arrow Z by a defined distance, and two further depressions are made in the profile area 12 in the manner described above brought in. This procedure is continued until the entire profile area is structured with depressions. In each case two mutually spaced recesses 10 are generated simultaneously. These recesses have a distance from one another which is greater than the distance between two immediately adjacent recesses. In the specific case, the distance A between the adjacent profiles P1 and P2 of the grinding wheel S is three times as large as the distance a between immediately adjacent recesses 10. This is best FIG. 3 (a) which shows a plan view of the outer peripheral region of the profile grinding tool WPS.

FIG. 3 (a) It can also be seen that the outer peripheries of the profiles P1 and P2 of the grinding wheel S have a cross section which corresponds to the cross section of the recess 10 of the structured embossing region 9. The outer circumferential profile of the profiles P1 and P2 is trapezoidal. Correspondingly, depressions 10 with a trapezoidal cross-section result. Adjacent recesses 10 are arranged at such a distance from each other that elevations 11 remain between them, whose cross-sectional profile corresponds to the cross-sectional profile of the recesses 10, that is also trapezoidal. In this way, on the surface of the tool plate 12, an embossing region 9 having a very regular wave-like structure with alternating, equally wide depressions and elevations is obtained. Such a structured embossing area is also in FIG. 13 shown.

FIG. 3 (b) shows an enlargement of the designated with the dotted line section O the FIG. 3 (a) , The figure is intended to illustrate some preferred dimensions of the grinding tool WPS and of the structured embossing area 9 produced with it, with its recesses 10 and elevations 11. In this case, α denotes the angle of the flanks of the profile region P (in which case P1 equals P2), which simultaneously corresponds to the angle of inclination of the flanks of the recesses 10 in the embossing region 10. The angle α is preferably between 60 and 150 °, particularly preferably 70 to 140 ° and in particular 90 to 120 °. The height H of the profile regions is preferably in a range of 0.05 to 0.5 mm and in particular between 0.08 and 0.2 mm. The width B of the frontal edge surfaces of the profile regions is preferably in a range of 0 to 1 mm, preferably 0.1 to 0.3 mm, resulting in 0 mm depressions with triangular cross-section. The width b of the saddle surfaces of the elevations 11 is determined by the distance with which the depressions 10 are generated in the region to be structured. Preferred values here are 0 to 1 mm, where 0 mm means that the depressions are placed next to one another without gaps. The side length at the bases of the surveys results from the remaining dimensions.

FIG. 2 shows a further possibility of the production of depressions 10 in the structured embossing region 9: In contrast to that in FIG FIG. 1 The method shown here, the wells are not ground, but milled. For milling, a milling tool WFS with two mutually parallel milling discs FS1 and FS2 is used. Except for the milling discs instead of the grinding wheels, the milling tool corresponds to the profile grinding tool FIG. 1 , The milling of the depressions 10 differs from the grinding process in that the milling tool WFS is guided over the profile region 12 in one direction only, namely in the direction of the arrow X, in accordance with the orientation of the cutting teeth.

FIGS. 6 and 7 show milling tools, as in the method according to FIG. 2 can be used. In both cases, the profile areas P1 and P2 are arranged at a distance A from one another which corresponds to three times the distance a between adjacent recesses 10. In FIG. 7 the profile areas P1 and P2 are formed on the outer circumference WA of a milling cutter WWF. The distance between the profile areas P1 and P2 is therefore, as in the grinding tool after FIGS. 1 and 3 , not variable. This is different with the milling tool WFS, which in FIG. 6 is shown. Here are two separate milling discs FS1 and FS2 mounted on a rotation axis R. The distance A between the milling discs FS1 and FS2 can therefore be set in principle to a different distance A than three times the distance between the recesses 10. The milling tool WFS of FIG. 6 can therefore also be used for recesses 10 at different distances from each other than in FIG. 6 shown by the milling discs FS1 and FS2 are shifted on the axis R against each other. In this case, the spacing of the depressions 10 from one another within the same embossing region 9 can be varied, or, if desired, be formed differently from embossing region to embossing region. The profile areas P1 and P2 on the outer circumference of the Frässcheiben FS1 and FS2 and on the outer peripheral surface WA of the milling cutter WWF in FIG. 7 are each designed so that arise wells with trapezoidal cross-section.

In FIGS. 4 and 5 the production of the depressions of the structured embossing region 9 is represented by end milling cutters. With the end mills WSF each individual recesses are generated by the end mill is guided sequentially along individual straight lines over the embossing area to be structured. In this case, the end mill rotates about the axis of rotation R. It is milled with the front end edge of the end mill WSF, which is provided for this purpose with a profile range P whose profile corresponds to the cross-sectional shape of the recesses 10. The end mills are in each case employed from depression to depression at the same angle to the surface of the embossing region 12 to be structured. The profile area P1 of in FIG. 4 illustrated end mill WSF is designed so that recesses result with triangular cross-sectional profile. With the in FIG. 5 on the other hand, trapezoidal profiles are produced.

FIG. 8 illustrates the production of depressions by die sinking by means of an electrode WSE. The electrode is made of a conductive material such as copper or graphite. During the die sinking process, the electrode WSE is subjected to voltage, and the elevations E present on one of the electrode surfaces dig into the surface of the embossing region 9 to be patterned and thus produce the depressions 10 in the present case generates trapezoidal cross section, which is why the cross sections of the elevations E of the electrode WSE also have a trapezoidal cross-section. The introduction of the depressions V for structuring the electrode surface is expediently carried out using one of the grinding or milling methods described above. However, any other suitable structuring method can also be used, for example one of the methods described below. The advantage of the die-sinking method is that the entire structuring of the embossing area 9 can be produced in a single work step.

In FIG. 9 the recesses 10 of the embossing region 9 are produced with a Milling tool WFF. For this purpose, a stylus or incision cutter is used, which is rotated about its longitudinal axis R, as is illustrated by the annular arrow. In the tip region of the form milling cutter WFF a profile region P is present, which is designed so that recesses 10 with a predetermined cross-sectional profile - again a trapezoidal cross-sectional profile - are generated. The material removal takes place with the cutting edge SC in the profile area. The recesses 10 are again generated individually and successively by the stylus along the parallel lines on the embossing area 9 is guided.

FIG. 10 illustrates the generation of the depressions 10 on the embossing region 9 by means of a non-contact method, namely by laser ablation with a laser device WLS. Again, the recesses are produced individually and sequentially by vaporization of metallic material. It may be necessary to guide the laser beam per well several times along the extension direction of a depression 10 in order to produce a specific cross-sectional profile.

In FIG. 11 the generation of pits is clarified by an ultrasound-assisted method. Here, a pin with profiled tip successively in parallel to each other Lines on the embossing area 9 out to produce mutually parallel linear recesses 10, here again have a trapezoidal cross-sectional profile. The pin WUS is thereby rotated again, as illustrated by the circular arrow. At the same time the pen is vibrated by means of ultrasound to improve the removal. This is to be clarified by the circular lines in the lower area of the pin and the double arrow Z. Such ultrasound-assisted removal methods are also known by the name "ultrasound" method. Suitable devices are available, for example, from Sauter GmbH (www.gildemeister.com).

FIG. 12 illustrates the formation of the recesses 10 by means of shaping loops. In the form of grinding tool WS while a profiled grinding pin is used, which is rotated about its longitudinal axis R. The profile region P is designed such that recesses with a trapezoidal cross section are formed. The procedure corresponds to that in connection with FIG. 9 has been described.

In the preceding figures, mainly methods for structuring the embossing area of an embossing tool have been described, which lead to completely symmetrical structures with recesses and elevations, each having a trapezoidal cross-section. However, this is just one possible type of surface structuring of the embossing area. In FIG. 4 has already been shown another example in which recesses 10 and elevations 11 have a triangular cross-section. FIGS. 14 to 17 show further examples of structuring of the embossing region 9, in which alternate each linear recesses 10 with linear elevations 11. In the embossing area 9 of the FIG. 14 the depressions 10 again have a triangular cross-section. Compared to FIG. 4 Here, however, the recesses are arranged at a greater distance from each other, so that the elevations 11 are not triangular, but trapezoidal in cross-section perpendicular to its longitudinal direction.

In FIG. 15 For example, the embossing area 9 has a wave profile with rounded cross sections of the recesses 10 and elevations 11 in each case. Also in FIG. 16 are the elevations 11 of approximately rounded cross-section. Only the upper apex area of the elevations 11 is flattened. This shape of the elevations 11 can be obtained either by a corresponding shaping of the profile region of the tool, with which the depressions 10 are introduced into the region 9 to be structured. On the other hand, it is possible to initially produce the elevations 11 with a height greater than the final height and then to reduce the surface of the elevations 11 over their whole height or partially, for example by grinding off the structured embossed area 9 over a large area.

In FIG. 17 a structuring of the embossing region 9 is shown, in which the cross section of the depressions 10 and corresponding to the cross section of the elevations 11 bounded by the depressions 10 is asymmetrical. This asymmetry is expediently predetermined by appropriate profiling of the profile region of the tool. In the example shown, the asymmetry consists in that the left flanks of the elevations 11 in the figure each rise less steeply than the right flanks of the elevations in the figure.

All of the examples of the structured embossed regions 9 described hitherto have depressions 10 which were each arranged only on a group of mutually parallel lines. Accordingly, both the depressions and the elevations extend uninterruptedly over the entire width of the structured embossing region 9. FIGS. 18 and 19 illustrate examples of the structuring of embossed areas 9, in which the depressions run on several, specifically two sets of virtual linear lines. In the cases shown, the recesses 11 generated along the straight lines each extend at an angle of 90 ° to each other. This results in elevations 11, whose length is less than the extent of the embossing region 9. In both examples, the cross section of the recesses 10 each trapezoidal again. In the example of FIG. 18 the recesses 10 running obliquely upwards in the image are cut by two depressions 10 'and 10 "running perpendicularly to them, thereby obtaining bar-like elevations 11 of different lengths.

In FIG. 19 both the depressions 10 extending obliquely upward in the image and the depressions 10 'running transversely thereto are arranged at the same distance from one another. This results in elevations 11, which have the shape of a Pentaederstumpfes. Also in the two examples of FIGS. 18 and 19 For example, the planar surfaces of the elevations 11 can be produced either by correspondingly producing the depressions 10, 10 'and 10 "or subsequently by abrading (eg grinding, milling off) the surface of the elevations 11.

FIG. 20 shows the arrangement of two opposing embossed areas 9. As can be seen, the recesses 10 and 10 'and elevations 11 and 11' uniformly over the entire surface of the embossing areas 9 and 9 'are formed. As a result, the elevations of one stamping area can engage in the depressions of the other stamping area, and vice versa. A metal plate inserted between both embossing regions 9 and 9 'therefore becomes by compressing the two embossing regions 9 and 9' on both surfaces with a complementary surface structuring Mistake. In the embossed material in this way not only a high degree of deformation is achieved, but it is also achieved a material thickening in the embossed area.

Figure 21 (a) shows an arrangement of the embossing areas 9 and 9 ', which are in essential parts of those of FIG. 20 equivalent. The lower die 9 'differs from that of the FIG. 20 in that a part of the elevations 11 'has a lower height than the adjacent elevations. This is best in FIG. 21 (b) to recognize a cross section through the arrangement of Figure 21 (a) in the circled area shows. As can be seen, the lower embossing area 9 'has a topography in such a way that the elevations 11' shown in the middle region of the figure have a lower height than the elevations further out. In this case, the height decreases continuously towards the middle of the area shown. The illustrated topography is transferred to the stamping of a metal plate between the embossing areas 9 and 9 '.

FIGS. 22 (a) to (d) illustrate various possibilities for the production of isolated embossed areas 9. This is to take place on the example of a structuring of the embossing area, which corresponds to that of the FIG. 19 equivalent. For this purpose, parallel to one another linear recesses 10 are generated on a tool plate 12 initially over the entire surface. Subsequently, perpendicular to these again over the entire surface of the plate 12 more linear depressions 10 'are introduced into the plate. This results in the FIG. 19 shown raster pattern. From this structured tool plate 12, the required stamping areas 9 can now be produced.

A first option is in Figure 22 (c) shown. For this purpose, the elevations 11 which are outside the required embossing areas and which have been produced by the preceding patterning steps on the entire board surface are removed. The removal of the surveys can be done for example by grinding or milling. Outside the embossed areas 9, therefore, recesses 19 are generated, similar to that in FIG FIG. 23 is still shown.

Another possibility is in Figure 22 (d) shown. Here, the required embossed areas 9 are separated out of the structured plate 12. This can be done for example by wire erosion. These cut-out embossing regions 9 are then inserted at the intended location of a stamping mold such that the structured surface projects beyond the adjacent surfaces of the stamping mold (cf. FIG. 23 ). In Figure 22 (d) the elevations around the embossment areas 9 are again removed. However, this is not absolutely necessary if the structured embossed regions 9 are cut out of a structured tool plate 12. Rather, the embossed areas can also directly from the structured plate 12 of the Figure 22 (b) be removed without the elevations 11 adjacent to the embossing areas being reduced in height or completely removed. The production of embossed regions of a required shape from the prefabricated structured tool plates 12 has the advantage that embossing regions of any shape can be generated quickly and easily if required.

In FIG. 23 an embossing tool 1 is shown, which is produced by the method according to the invention. The embossing tool 1 has two opposing embossing dies 3 and 4, which can be moved by means of frame members 13 and 14 with the help of a press along the guide pins 15 toward and away from each other. The upper embossing mold 3 has on its surface 6 on three embossing areas 9, each having a textured surface facing in the direction of the other embossing mold 4. Over the entire surface of the respective embossing region 9 extend parallel to each other arranged linear recesses, between which are each linear elevations. In the case shown, each stamping area has, for example, a surface structure as shown in FIG FIG. 15 is shown. Each of the embossing regions 9 of the upper embossing mold 3 is opposed by a stamping region 9 'on the surface 7 of the lower embossing mold 4. The structuring is again wave-like and corresponds to that of the upper embossing regions 9, but the depressions and elevations of the lower embossing regions 9 'are laterally offset from those of the embossing regions 9 so that the elevations 11' can engage in the depressions 10 of the upper embossing regions 9, Similar to the trapezoidal structures in FIG. 20 is shown. When pressing together upper and lower embossing molds 3, 4, the structured embossed regions 9 and 9 'emboss in the surfaces 16 and 17 of a metal plate 2 inserted between the embossing molds.

FIG. 23 shows a metal plate 2 immediately after completion of the embossing process. As can be seen, not the entire surface of the metal plate has been provided with surface structures 8, but between the surface structures 8 unstructured areas 18 remain. In order to prevent the surfaces 16 and 17 of the metal plate 2 in the regions 18 from being influenced by the embossing process, recesses 19 are present in the sections of the embossing shapes corresponding to the regions 18. At the in FIG. 23 shown metal plate 2 may be, for example, a gasket layer of a metallic gasket. In the areas not provided with a surface structuring 8, for example, in a subsequent embossing process with another embossing tool, a bead can be embossed for the purpose of sealing a passage opening. Since in the regions provided with the surface structuring 8 the material thickness of the gasket layer is increased compared to the original thickness of the gasket layer, these surface-structured regions 8 can also serve to protect the bead during operation from complete flattening.

Claims (21)

Method for producing an embossing tool (1) for producing at least one area provided with a surface structuring on at least one surface of a metal plate (2), wherein the embossing tool (1) has two mutually opposite embossing forms (3, 4) 5) for receiving the metal plate (2), wherein at least one of the embossing molds (3, 4) on its surface facing the other embossing mold (6, 7) at least one to the surface to be generated structuring (8) complementary structured embossing region (9) having alternating depressions (10) and elevations (11),
characterized,
in that the depressions (10) are produced as groove-shaped depressions such that they lie on at least one group of substantially straight parallel virtual lines (L) extending over the entire extent of the structured embossing region (9). Method according to claim 1,
characterized,
in that the recesses (10) are produced by: grinding, in particular profile grinding, milling, in particular rolling, disc-shank or shape milling, erosion, laser radiation, ultrasound erosion or engraving. Method according to claim 1 or 2,
characterized,
that the tool (W) to produce the recesses (10) with at least one profiled region (P) is provided, whose cross-sectional shape of the cross-sectional shape of the recesses (10) corresponds to a to their longitudinal extension perpendicular direction. Method according to claim 3,
characterized,
in that the tool has a plurality of profile regions (P1, P2) arranged parallel to one another, with which a plurality of depressions (10) are generated simultaneously. Method according to claim 4,
characterized,
that the profile regions (P1, P2) have a spacing (A) from one another which corresponds to a multiple of the distance (a) between immediately adjacent depressions (10). Method according to one of the preceding claims,
characterized,
in that the recesses (10) are produced with a tool selected from: a profile grinding tool (WPS) with a grinding wheel (S), on whose outer circumference at least one profile area (P1, P2) is formed, a milling tool (WFS) having at least one milling disk (FS1, FS2), on whose outer circumference a profile region (P) is formed, a roll mill (WWF), on the outer circumference (WA) of which at least one profile region (P1, P2) runs along a line on which the outer peripheral surface is cut by a plane perpendicular to the axial direction (R) of the roll, - An end mill (WSF), at the front end-side edge region of a profile area (P) is present, a molding cutter (WFF) whose front tip region has a profile region (P), a grinding tool (WS) with a grinding pin, on the front tip region of which a profile region (P) is formed, - An electrode (WSE) with at least one profile area (P) for Senkerodieren and - An ultrasonic ablation tool (WUS), the tip of which has a profile area (P). Method according to one of the preceding claims,
characterized,
that the tool is guided along the virtual straight lines (L) over the area to be structured, wherein it is laterally offset from the previous line in a direction perpendicular to the direction of extension thereof. Method according to one of the preceding claims,
characterized,
that an embossed region (9) with wave-like parallel extending recesses (10) is formed with intervening raised ribs (11). Method according to one of claims 1 to 7,
characterized,
in that depressions (10, 10 ', 10 ") are generated which run along at least two intersecting groups of virtual straight lines. Method according to claim 9,
characterized,
that the depressions (10, 10 ', 10 ") at an angle of 30 to 150 °, preferably 45 to 135 °, particularly preferably 80 to 100 ° and in particular 90 °, are generated to each other extend. Method according to claim 9,
characterized,
that the depressions (10, 10 ', 10 ") are generated running on three sets of virtual straight lines, which preferably intersect at an angle of 60 °. Method according to one of the preceding claims,
characterized,
that the depressions (10, 10 ', 10 ") produced with a trapezoidal, triangular, rounded or rectangular cross section. Method according to one of the preceding claims,
characterized,
in that the depressions (10, 10 ', 10 ") are produced so that elevations (11) with a dome-shaped, rectangular, triangular or trapezoidal cross-sectional profile remain. Method according to one of claims 9 to 13,
characterized,
that the elevations (11) have the shape of a polyhedron stump. Method according to one of the preceding claims,
characterized,
that the elevations (11) are partially reduced in height within the embossing area (9). Method according to one of the preceding claims,
characterized,
that the depressions (10, 10 ', 10 ") in a region (12) are generated, which is greater than the emboss area (9), and then the projections (11) in areas outside of the embossing portion (9) reduced in height and preferably completely removed. Method according to one of claims 1 to 15,
characterized,
that the depressions (10, 10 ', 10 ") in a region (12) are generated, which is greater than the emboss area (9), and then the embossing area (9) cut out and at a predetermined location in one of the die members (3 , 4) is used. Method according to claim 15 or 16,
characterized,
that the elevations (11) are reduced in height by grinding or milling. Method according to one of the preceding claims,
characterized,
that the grooves' are (, 10 "generated such that the elevations (11) of an embossing region (12) of an embossing mold (3) in the recesses (10 10, 10) '() of an opposing embossing region (12') of the other embossing form 4) can intervene. Method according to one of the preceding claims,
characterized,
that an annular embossing region (9) is produced. Method according to one of the preceding claims,
characterized,
in that the metal plate (2) is a metallic gasket layer or a part of a metallic gasket layer of a flat gasket, in particular a cylinder head gasket, exhaust manifold gasket or flange gasket.

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