Extrusion die and method for producing extrusion die

Abstract

The invention relates to an extrusion die having a support structure made of a steel sheet. The extrusion die is formed from an extruded sheet or endless belt and is designed to press a material sheet in a hot press. In this case, the support structure of the extrusion die has a coarse structure having a depth of at least 150 [mu] m produced by at least one process. At least one partial region of the coarse structure is rounded by polishing. The surface of the extrusion die has a fine structure manufactured by at least one process. The invention further relates to a method for producing the extrusion tool and to a method for producing a material panel using the extrusion tool.

Description

Technical Field

[0001] The invention relates to an extrusion die for imitating wood, a method for manufacturing an extrusion die for imitating wood and a method for manufacturing a material board. Background Art

[0002] Material boards, for example wood material boards, are required for the furniture industry and for interior construction, for example for laminate floors. The material boards have a core made of MDF (medium density fiberboard) or HDF (high density fiberboard), to which various material applications, for example (optical) decorative layers and protective layers (covering layers), are applied at least on one side.

[0003] In order to avoid warping in the material sheets being manufactured, such material sheets are usually provided with the same number of material application parts on both sides; in order to connect the individual layers of the material sheet (core, material application parts, etc.) to one another, the layers are pressed against one another in a press using special extrusion dies, in particular extrusion plates or endless belts. The surface of the material sheet is also printed here. A hot press is usually used here in order to connect the different material application parts made of thermosetting plastic resins, for example cyanamide resins, to the surface of the core under the action of heat by melting the plastic material.

[0004] The decorative layer determines the pattern and coloring of the material panel; the desired surface structure can be achieved by using a matching extrusion die. For example, a wood or tile decoration can be embossed on the decorative layer (decorative paper), or a decorative layer can be used that includes a pattern and coloring that is artistically designed to suit the respective intended use. Covering layers can also be used here, which are embossed on the top or bottom.

[0005] In order to improve the realistic reproduction, in particular in material panels comprising wood, tiles or natural stone decorations, the extrusion die is provided with a surface structuring which is formed in conformity with the decorative layer and forms a negative mapping of the desired surface structure. Thus, the extrusion die has, for example, a 3D profile (depth structuring) which simulates the wood grain of a wood surface in order to give the decorative layer of the material panel the image of such a wood surface.

[0006] In order to achieve a consistent printing of the material sheet, i.e. the required matching accuracy of the decorative layer and the surface structure of the material sheet, high quality standards are required for the production of the extrusion dies. In particular, the extruded sheet or endless belt is used here as upper and lower tool in a short-cycle press equipped with an extruded sheet or in a double-belt press in the case of an endless belt, wherein the material sheet is printed and heated simultaneously, so that the thermosetting plastic resin of the decorative and / or covering layer of the material sheet first melts, the surface structure corresponding to the surface structure of the extrusion die is introduced into the material application located outside, and the structured material application is connected to the core of the material sheet by subsequent hardening.

[0007] In order to produce the desired surface structuring in or on the extrusion die, for example, digitized image data of a decorative sample can be used in order to apply an anti-corrosion portion for the structured portion of the extruded sheet or the endless belt. For this purpose, the anti-corrosion portion is applied to the extruded sheet or the endless belt, for example, by means of a digital printer, in order to subsequently carry out an etching process. After the removal of the anti-corrosion portion, further processing of the extrusion die can be carried out, wherein preferably multiple etching processes can be carried out successively in the surface structuring portion including particularly deep / high structures. For this purpose, the anti-corrosion portion is applied again to the already corroded extruded sheet or endless belt and a new etching is carried out until the desired deep structure is produced. In the individual etching processes, coarse or fine structuring of the surface structuring portion can also be carried out depending on which surface structure of the material sheet is to be given.

[0008] Alternatively or in addition to the described erosion methods or other methods for abrading materials, methods for applying materials (in layers) to produce surface structuring on the surface of the extrusion die can also be used. In most of these methods, masks (masking) are used, by which the surface of the extrusion die is to be protected before the subsequent application or removal of material. By repeatedly applying the corresponding masks and the subsequent application or removal of material, surface structuring of various designs can be produced.

[0009] Independent of the respectively selected method, a surface structuring is finally produced on the extrusion die, which forms the negative of the surface structure to be embossed into the material sheet. Here, the elevations in the surface structuring correspond to the depressions to be embossed in the surface structure of the material sheet, or the depressions in the surface structuring correspond to the elevations that the surface structure of the material sheet should have.

[0010] In order to further improve the realistic reproduction of natural surfaces, in particular wood, tile or natural stone surfaces, extrusion dies are used which also have different gloss levels. By adjusting the respectively determined gloss level in selected surface areas of the extrusion die, it is possible to produce possible reflections or shadows in the material sheet, which for example intensify the impression of a natural wood, tile or natural stone surface for the observer. For this purpose, thin chrome layers with different gloss levels are used in the prior art, for example, wherein the entire surface of the extrusion die is first chrome-plated and then another chrome layer is applied, which covers only the protruding areas of the surface structure or only the darker areas thereof (EP 3010 704 B1).

[0011] EP 2 839 970 A1 discloses a method for producing a hydrophobic or superhydrophobic surface shape of an extrusion die in the form of an extruded sheet, endless belt or printing roller. In order to improve the cleaning capabilities of the material sheet produced using the extrusion die, a microstructuring is provided on the surface.

[0012] EP 2 060 658 A2 discloses a method for processing a structured surface of a printing mold, wherein the surface is provided over the entire surface with a metallic first coating in order to simulate wood pores.

[0013] EP 2 289 708 A1 discloses a method for producing the surface structure of metallic extruded sheets, endless belts or printing rollers by means of at least one laser, and a device for using the method. The deep structure is produced by means of the laser.

[0014] Extrusion dies, for example in the form of extruded sheets, endless belts or printing rollers, have a structured extrusion surface and are used, for example, in the wood processing industry, for example to produce furniture, laminates or panels, that is, in general, to produce material panels. The material panels are pressed using the structured extrusion surface of the extrusion die, so that the workpiece receives a structured surface corresponding to the structured extrusion surface.

[0015] However, the disadvantage of the methods known to date is that the design possibilities are limited, i.e., for example, the imitation of wood materials has hitherto only been possible incompletely and in particular the desired antique look, i.e. a noticeable degree of wear and tear, cannot be easily produced. In contrast to the reproduction of wood and stone appearances, the structure does not necessarily have to follow the pattern. Older natural floors have strongly rounded and unevenly arranged and shaped areas. Summary of the invention

[0016] The object of the present invention is therefore to overcome the disadvantages of the prior art and to provide an extrusion die and a method for producing an extrusion die, by means of which the imitation of wood as material can be achieved better and the degree of wear can be produced more easily.

[0017] This object is achieved by an extrusion tool, a method for producing an extrusion tool arrangement and a method for producing a workpiece according to the claims.

[0018] According to a first aspect of an embodiment, an extrusion die for imitating wood has a support structure made of steel sheet, which is formed by extruded sheet metal or annular belt and is designed for pressing a material sheet in a hot press. The support structure is understood to be a load-bearing area of ​​the extrusion die, which is arranged in an unstructured and preferably flat surface of the extrusion die and is not penetrated (realized) by a coarse structure. The support structure preferably has a thickness of at least 500 μm, preferably at least 2000 μm or particularly preferably between 2000 and 5000 μm. In this case, the support structure of the extrusion die has a coarse structure with a depth of at least 150 μm produced by at least one process, at least one partial area of ​​the coarse structure is rounded by laser polishing and thus corresponds to the wood grain, and the surface of the extrusion die has a fine structure produced by at least one process.

[0019] According to a second aspect of the embodiment, a method for producing an extrusion die for imitating wood comprises the steps of producing a coarse structure having a depth of at least 150 μm on a support structure of the extrusion die by at least one machining process, rounding at least one partial region of the coarse structure by laser polishing so that a partial region (4) of the coarse structure (2) corresponds to the wood grain, and producing a fine structure on the surface of the extrusion die by at least one machining process. Here, the extrusion die also has a support structure made of sheet steel, is formed by an extruded sheet or an endless belt and is designed for pressing a material sheet in a hot press.

[0020] According to a third aspect of the embodiment, in a method for producing a material panel comprising a structured surface by pressing, such an extrusion die is used for pressing the material panel.

[0021] It has been shown that the extrusion die and method of the first embodiment can very individually configure the overall impression of a workpiece, for example a pressed laminate, and can, for example, simulate heavily worn wood. In addition, branches can thus be better simulated in their natural appearance.

[0022] Further embodiments may relate to each of the above-mentioned aspects.

[0023] According to a further embodiment, the coarse structure has a depth of between 150 μm and 2000 μm. A depth of between 150 μm and 1500 μm is particularly preferred.

[0024] The laser can be directed at different angles onto the coarse structure. The laser can preferably be guided onto the coarse structure with adjustable parameters, such as abrasive power, and at an adjustable speed and a variable distance. In a particularly preferred manner, selectively determined areas of the coarse structure, such as sharp edges or larger areas of the coarse structure, can be processed. The laser can be controlled according to a grayscale file of a 3D data set or the desired rounding of the extrusion die. For example, more areas to be processed will appear darker in the grayscale file. In the case of a grayscale file, specific parameters of the laser control can preferably be assigned to the individual grayscale values.

[0025] According to another embodiment, one or more coatings are applied to the support structure over the entire surface or in part, and the surface of the extrusion die is formed by the surface of the uppermost coating of the entire surface or by the uppermost partial surface of the coating of the partial surface. In the method, one or more coatings are applied to the support structure over the entire surface or in part before the coarse structure is produced.

[0026] According to another embodiment, at least one region of the surface of the extrusion die has a first glossiness.

[0027] According to another embodiment, at least another region of the surface of the extrusion die has a second glossiness that is different from the first glossiness.

[0028] According to a further embodiment, each of the coatings is metallic, ceramic or contains plastic.

[0029] According to a further embodiment, at least one of the coatings is a chrome layer or a nickel-plated or nickel-containing coating.

[0030] According to a further embodiment, at least one region of at least one coating is formed by laser processing, matte etching, sandblasting or chemical treatment.

[0031] According to a further embodiment, the edge of at least one coating is interrupted by intense polishing.

[0032] According to another embodiment, at least one of the processes comprises one or more of extrusion, printing, etching, polishing, laser processing, grinding, milling and applying another coating or a combination thereof.

[0033] According to a further embodiment, at least one coating is applied to the support structure by chemical deposition.

[0034] The embodiments described represent possible embodiment variants, wherein the invention is not restricted to the specifically illustrated embodiment variants, but rather any combination of individual embodiment variants with one another is also possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to better understand the present invention, it is further explained with the help of the following drawings.

[0036] Respectively in a strongly simplified schematic:

[0037] Figure 1 An extrusion die according to one embodiment is shown by way of example;

[0038] Figure 2 The rough structure according to one embodiment is shown by way of example;

[0039] Figure 3 A rounded coarse structure according to one embodiment is shown by way of example; and

[0040] Figure 4 The fine structure according to one embodiment is shown by way of example. DETAILED DESCRIPTION

[0041] Firstly, it is provided that identical parts are provided with the same reference numerals or the same component names in the various described embodiments, wherein the disclosure contained in the entire description can be transferred to the same parts with the same reference numerals or the same component names in a meaningful manner. Selected positional descriptions in the description, such as top, bottom, side, etc., also refer to the directly described and illustrated figures and these positional descriptions are transferred to the new positions in a meaningful manner in the event of a change in position.

[0042] Figure 1 An extrusion die 1 is shown for imitating wood, including a structure applied thereto, which is transferred to a workpiece during pressing of the workpiece with the extrusion die 1, for example in a hot press. Thus, for example, a structure corresponding to the grain of wood can be transferred to the workpiece. As a result, the workpiece acquires a wood appearance, i.e. it looks like wood.

[0043] In order to produce this structure on the extrusion die 1, the processing can be, for example, an extrusion die 1 of an extruded sheet or an endless belt. The processing can be performed by sandblasting, chemical treatment, extrusion, printing, corrosion, polishing, laser processing, grinding, milling and coating application or by a combination of multiple thereof.

[0044] Figure 2The cross section of the coarse structure 2 produced by at least one machining process on the support structure of the extrusion die 1 is shown. The machining depth is at least 150 μm here. The machining depth can be a depth between 150 μm and 2000 μm, wherein a depth between 150 μm and 1500 μm is particularly preferred.

[0045] Each processing here can be performed by one of sandblasting, chemical treatment, extrusion, printing, etching, polishing, laser processing, grinding, milling and coating application or by a combination of a plurality thereof.

[0046] exist Figure 2 It is also shown in FIG. 2 that the coarse structure 2 has sharp edges or is of very angular design at some locations 3 .

[0047] Figure 3 The cross section of the rounded coarse structure 2 of the extrusion die 1 is shown. At least one partial region of the coarse structure 2 is rounded by laser polishing. By laser polishing, the edges of the coarse structure 2 or a partial region thereof are rounded, which makes it possible to give the coarse structure 2 or a partial region thereof a softer appearance. It is also advantageous here that the tactile feel is changed and the similarity to wood is improved by the softer edges.

[0048] The undulations of the coarse structure 2 are rounded by laser polishing. Here, the undulations of the entire coarse structure 2 of the extrusion die 1 are rounded by laser polishing or only the undulations of a partial region of the coarse structure 2 of the extrusion die 1 are rounded by laser polishing.

[0049] In laser polishing, the thin edge layers of the structure are rounded due to the action principle of remelting and leveling of the liquid material due to the interfacial tension. For laser polishing, for example, a solid-state laser can be used. Depending on the state of the surface to be rounded, a pulsed laser with a pulse length of several hundred nanoseconds or a continuous laser can be used.

[0050] By using a laser for polishing, automated rounding of three-dimensional surfaces with equal rounding quality can be achieved. In particular, higher processing speeds can be achieved compared to manual polishing. In addition, reproducibility can be guaranteed, i.e. all extrusion dies can be identical.

[0051] Furthermore, laser polishing generates little mechanical load on the extrusion die 1, since laser polishing is a contactless method. Therefore, no grinding or polishing waste is generated, and it is not necessary to introduce grinding and polishing agents into the surface.

[0052] Figure 3 It is shown that some previously sharp edges or angular regions 3 are rounded, which are designated as rounded regions 4 .

[0053] Figure 4The cross section of a fine structure 5 produced on a rounded coarse structure 2 is shown. The fine structure 5 is produced here by at least one machining operation on the surface of the extrusion die 1 .

[0054] Here, each processing can also be performed by one of sandblasting, chemical treatment, extrusion, printing, etching, polishing, laser processing, grinding, milling and coating application, or by a combination of a plurality thereof.

[0055] To produce such an extrusion die 1, a coarse structure 2 is first produced by at least one machining process on the support structure of the extrusion die 1. Subsequently, at least one partial region of the coarse structure 2 is rounded by laser polishing. Then, a fine structure 5 is produced on the surface of the extrusion die 1 by at least one machining process.

[0056] As already stated above, each of the processing can be performed by one of sandblasting, chemical treatment, extrusion, printing, etching, polishing, processing with a laser, grinding, milling and coating application or by a combination of a plurality thereof.

[0057] Alternatively or in addition to what has been described so far, one or more coatings can be applied to the entire surface or partial surface of the support structure. In this case, the surface of the extrusion die 1 is formed by the surface of the uppermost entire surface coating or by the uppermost partial surface of the partial surface coating. In this case, a plurality of partial surfaces can form the total surface of the surface.

[0058] The coating or coatings can be applied here before the production of the coarse structure 2, so that the coarse structure 2 is produced in the coating. However, the coating can also be applied only after the coarse structure 2 is produced in the support structure of the extrusion die 1. Even after the rounding by polishing and before the production of the fine structure 5, the coating can also be applied. Finally, the coating can also be applied after the production of the fine structure 5.

[0059] This makes it possible to produce a first glossiness in one or more regions of the surface of the finished extrusion die 1. The region or regions can be regions in which the coarse structure 2 is rounded, but also regions that are no longer changed by the rounding.

[0060] But alternatively, glossiness can also be produced by processing. Each of these processes can be performed by sandblasting, chemical treatment, extrusion, printing, corrosion, polishing, laser processing, grinding, milling and coating application or by a combination of a plurality of them.

[0061] By applying different coatings or by different processing of the coatings, at least another area of ​​the surface of the extrusion die 1 can have a second glossiness different from the first glossiness. It is also possible to produce two different glossinesses by processing one or more areas and one or more areas remaining unprocessed or uncoated.

[0062] Each of these coatings can be metallic, ceramic or plastic-containing. For example, DE 10 2019127 659 A1 describes a plastic-containing coating, wherein a lacquer layer or plastic layer preferably having polyetheretherketone or polyetheretherketone is described, optionally also with the addition of mineral particles.

[0063] At least one of the coatings may be a chrome layer or a nickel-plated or nickel-containing coating. In addition, one or more regions of the coating may be formed by laser processing, matte etching, sandblasting or chemical treatment. In addition, the edge of at least one coating may also be interrupted by intensive polishing. The polishing may also be laser polishing.

[0064] Each of the above-mentioned coatings can also be applied by chemical deposition. As already explained, each coating can be applied on a structure-free support structure, on a coarse structure, on a (partially) rounded coarse structure and also on a fine structure.

[0065] Finally, it should be mentioned again that each of the processes listed here can be carried out by one of sandblasting, chemical treatment, extrusion, printing, etching, polishing, laser processing, grinding, milling and coating application or by a combination of a plurality thereof.

[0066] In order to produce a workpiece, ie a material plate, using an extrusion die produced in this way, a method for producing a material plate comprising a structured surface by pressing is used, wherein an extrusion die as described above is used for pressing the material plate.

[0067] The various embodiments illustrate possible implementation schemes, wherein it should be noted that the present invention is not limited to the specifically illustrated implementation schemes, but different combinations of the various implementation schemes with one another are possible and these variations are within the capabilities of a person skilled in the art based on the teaching of the technical processing by the specific invention.

[0068] The scope of protection is determined by the claims. However, the claims should be interpreted with reference to the description and the drawings. Individual features or combinations of features from the different embodiments shown and described can themselves be independent inventive solutions. The tasks on which the independent inventive solutions are based can be derived from the description.

[0069] All descriptions of value ranges in this specification should be understood as including any and all partial ranges therein. For example, the description 1 to 10 should be understood as including all partial ranges starting from the lower limit 1 and the upper limit 10, that is, all partial ranges starting with a lower limit of 1 or greater and ending with an upper limit of 10 or less, for example 1 to 1.7 or 3.2 to 8.1 or 5.5 to 10.

[0070] Finally, it should be pointed out that, in order to achieve a better understanding of the construction, some elements are partially not shown to scale and / or are shown enlarged and / or reduced in size.

[0071] Reference numerals list

[0072] 1Extrusion die

[0073] 2 Coarse structure

[0074] 3. Sharp edges or angular areas

[0075] 4. Rounded parts

[0076] 5 Fine structure

Claims

1. An extrusion die (1) for imitating wood, the extrusion die having a support structure made of steel sheet, formed by extruded sheet metal or an endless belt and designed for pressing a material sheet in a hot press, wherein The support structure of the extrusion die (1) has a coarse structure (2) produced by at least one machining operation and having a depth of at least 150 μm, At least one partial region (4) of the coarse structure (2) is rounded by laser polishing and thus corresponds to the wood grain, and The surface of the extrusion die (1) has a fine structure (5) produced by at least one process.

2. An extrusion die (1) according to any one of the preceding claims, wherein: The coarse structure ( 2 ) has a depth of between 150 μm and 2000 μm, particularly preferably between 150 μm and 1500 μm.

3. The extrusion die (1) according to any one of the preceding claims, wherein: The undulating parts of the entire rough structure (2) of the extrusion die (1) are rounded by laser polishing.

4. The extrusion die (1) according to any one of the preceding claims, wherein: One or more coatings are applied to the support structure over the entire surface or over a portion of the surface, and the surface of the extrusion die (1) is formed by the surface of the uppermost entire surface coating or by the uppermost portion of the portion of the surface coating.

5. The extrusion die (1) according to any one of the preceding claims, wherein: At least one area of ​​the surface of the extrusion die (1) has a first glossiness.

6. The extrusion die (1) according to any one of the preceding claims, wherein: At least another area of ​​the surface of the extrusion die (1) has a second glossiness different from the first glossiness.

7. The extrusion die (1) according to any one of the preceding claims, wherein: Each of the coatings is metallic, ceramic or plastic-containing.

8. The extrusion die (1) according to any one of the preceding claims, wherein: At least one of the coatings is a chrome layer or a nickel-plated or nickel-containing coating.

9. The extrusion die (1) according to any one of the preceding claims, wherein: At least one region of at least one coating is formed by laser machining, matte etching, sandblasting or chemical treatment.

10. The extrusion die (1) according to any one of the preceding claims, wherein: At least one edge of the coating is interrupted by intense polishing.

11. The extrusion die (1) according to any one of the preceding claims, wherein: At least one of the processes includes one or more of extruding, printing, etching, polishing, laser processing, grinding, milling and applying another coating, or a combination thereof.

12. The extrusion die (1) according to any one of the preceding claims, wherein: At least one coating is applied to the support structure by chemical deposition.

13. A method for producing an extrusion die (1) for imitating wood, wherein: The extrusion die (1) has a support structure made of steel sheet, is formed by an extruded sheet or an endless belt and is designed for pressing a material sheet in a hot press, wherein the method comprises: A coarse structure (2) having a depth of at least 150 μm is produced on the support structure of the extrusion die (1) by at least one machining operation, At least one partial region (4) of the coarse structure (2) is rounded by laser polishing, so that the partial region (4) of the coarse structure (2) corresponds to the wood grain, and A fine structure (5) is produced on the surface of the extrusion die (1) by at least one processing.

14. The method according to claim 13, wherein: Production of the coarse structure (2) A coarse structure (2) is produced with a depth of between 150 μm and 2000 μm, particularly preferably with a depth of between 150 μm and 1500 μm.

15. The method according to any one of claims 13 to 14, further comprising, before producing the coarse structure (2): One or more coatings are applied to the support structure over the entire surface or over a portion of the surface, whereby the surface of the extrusion die (1) is formed by the surface of the uppermost entire surface coating or by the uppermost partial surface of the partial surface coating.

16. The method according to one of claims 13 to 15, further comprising generating a first glossiness in at least one region of the surface of the extrusion die (1).

17. The method according to one of claims 13 to 16 further comprises generating a second glossiness different from the first glossiness in at least one other region of the surface of the extrusion die (1).

18. The method according to any one of claims 13 to 17, wherein: Each of the coatings is metallic, ceramic or plastic-containing.

19. The method according to any one of claims 13 to 18, wherein: At least one of the coatings is a chrome layer or a nickel-plated or nickel-containing coating.

20. The method according to claim 13, further comprising forming at least one region of at least one coating by laser processing, matte etching, sandblasting or chemical treatment.

21. The method according to claim 13, further comprising interrupting the edge of at least one coating by intensive polishing.

22. The method according to any one of claims 13 to 21, wherein: The at least one processing includes one or more of extruding, printing, etching, polishing, laser processing, grinding, milling and applying another coating or a combination thereof.

23. The method according to claim 13, further comprising applying at least one coating to the support structure by chemical deposition.

24. Method for producing a material sheet having a structured surface by pressing, wherein: For pressing the material sheet, an extrusion die (1) according to one of claims 1 to 12 is used.

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