Method for producing functional structure for high-frequency technology and functional structure for high-frequency technology

Abstract

The invention relates to a method for producing a functional structure for high-frequency technology, comprising the following steps: producing a pattern of the functional structure; the mold sample is placed into a molding material to be molded; drawing the pattern from the molding material such that a casting mold is produced; filling the melt into a casting mold; the solidified melt is demoulded, the mass of the mould being more than 90%, preferably more than 95%, in particular more than 99%, of a pure material.

Description

Technical Field

[0001] The invention relates to a method for producing a functional structure for high-frequency technology, the method comprising the following steps:

[0002] - Make the appearance of functional structures;

[0003] -Putting the pattern into the molding material and shaping it;

[0004] - demoulding the pattern from the molding material so as to produce a casting mold;

[0005] - Filling the melt into the casting mold;

[0006] - De-moulding the solidified melt. Background Art

[0007] It is known from the prior art to produce functional structures for high-frequency technology by means of cutting methods, such as turning or milling. The required geometric complexity of the functional structures can only be achieved with great effort. The functional structures are usually produced here using the complex split block method, and miniaturization of the functional structures is likewise possible only with great effort.

[0008] It is also known to produce functional structures using high-frequency technology by means of metal printing, such as selective laser melting (SLM). Disadvantages here are the rough surfaces and the limitation of geometric complexity, since support structures are already used early in the process. The raw materials for SLM, which can be present as powders or wires, are inefficient in terms of energy requirements and material utilization.

[0009] It is also known to manufacture a base body from plastic and to metallize it so as to produce a functional structure for high-frequency technology. A disadvantage of this is the poor thermal stability at high electrical powers. In addition, in most cases, plastic-based bodies have a poorer mechanical stability than their metal counterparts.

[0010] The production of functional structures for high-frequency technology by casting is also known.

[0011] The preferred characteristics of the functional structure of high-frequency technology are smooth surfaces to reduce losses and high geometric accuracy in the case of high geometric complexity. This can minimize the reflection of electromagnetic waves in the functional structure and radiate electromagnetic waves as desired when the functional structure is used as an antenna. Likewise, the functional structure of high-frequency technology should preferably be designed so that electromagnetic waves can be conducted through the functional structure at the highest possible frequency with acceptable attenuation. In particular, good thermal stability of the geometric structure should be sought in the case of high electrical power. In principle, there is a desire for sufficient mechanical strength. Summary of the invention

[0012] Against this background, the invention is based on the object of specifying a method for producing a functional structure of high-frequency technology having optimized properties.

[0013] This object is achieved by a method having the features of independent claim 1. Further advantageous developments of the invention are the subject matter of the dependent claims.

[0014] According to the invention, it is therefore provided that more than 90%, preferably more than 95%, in particular more than 99% of the mass of the pattern consists of pure material.

[0015] The material constituting the pattern therefore comprises more than 90%, preferably more than 95%, in particular more than 99% pure material. The remainder of the mass of the pattern is formed by other substances.

[0016] The invention also relates to a method for producing a functional structure for high-frequency technology having the features of claim 2. The following steps are proposed:

[0017] - Make the appearance of functional structures;

[0018] -Putting the pattern into the molding material and shaping it;

[0019] - demoulding the pattern from the molding material so as to produce a casting mold;

[0020] - Filling the melt into the casting mold;

[0021] - demoulding the solidified melt, wherein

[0022] The functional structure and / or pattern is a slotted waveguide and / or a waveguide with openings that do not radiate and / or a high-frequency component derived therefrom. Such a component is to be understood, for example, as a component having one (or more) slotted waveguides and / or one (or more) waveguides with openings that do not radiate.

[0023] Combinations of the features of claims 1 and 2 are also conceivable and are encompassed by the invention.

[0024] The casting mold can be a permanent mold.The casting mold can include a core which is preferably additively manufactured.

[0025] Likewise, according to the present invention, the functional structure is a slotted waveguide.

[0026] The pattern is preferably an ideally exact replica of the functional structure.

[0027] For casting reasons, in addition to the pattern, the casting system should preferably also be introduced into the molding material and shaped.

[0028] The casting system is used in particular to demold the pattern from the molding material and to fill the melt into the casting mold.

[0029] Preferably, structures, such as openings and channels in a casting mold, as well as corresponding structures shaped to form the openings and channels and the melt solidifying in said channels and openings are referred to as casting systems.

[0030] The casting system should preferably be removed after demoulding the solidified melt in order to produce a functional structure.

[0031] The casting system and pattern are preferably referred to as a model.

[0032] The slotted waveguide preferably has slots or openings at or in its side walls which do not radiate and are smaller than the guide wavelength. The slots or openings facilitate free cleaning of the wax pattern, i.e., facilitate the removal of support structures from the inner cavity and, in particular, the removal of the casting mold in the case of complex geometries. The corresponding materials and process media can flow in and / or out through the openings.

[0033] A slotted waveguide is preferably a waveguide in which an opening is provided in the outer wall which does not cause radiation. This is the case when the opening is small relative to the guided wavelength and / or the current density associated with the wave in the waveguide does not intersect transversely to its flow direction at the conductive wall.

[0034] Preferably, the rectangular waveguide is an opening in the narrow side of the waveguide.

[0035] It is preferably provided that the pattern is produced by means of an additive method, preferably a multi-component printing method, preferably a multi-jet printing method.

[0036] The pattern can be produced by means of an additive method, preferably a stereolithographic, synthetic resin-based and / or filament extrusion printing method and / or selective laser sintering.

[0037] It can be provided that a supporting structure is arranged on the pattern, wherein the supporting structure at least partially consists of a material different from the material of the pattern or also consists of the same material as the pattern.

[0038] The support structure can preferably be free from chemical cleaning. For example, the material of the support structure can be a material that is soluble in methanol and / or isopropanol and / or other solvents.

[0039] It is preferably provided that the supporting structures of the pattern which are required for additive manufacturing are removed before the pattern is placed in the molding material and shaped.

[0040] Multi-component printing can be, for example, two-component printing and can also be referred to as multi-jet.

[0041] The pattern can also be produced by selective laser sintering (SLS), stereolithography (SLA) or by casting, such as injection molding. The pattern can also be created by means of FDM (Fused Deposition Modeling), that is, filament fusion method.

[0042] It is preferably provided that the pure material is wax, plastic, tin or lead, or another metal.

[0043] In particular, in an embodiment in which the pure material is wax and the pattern is produced by means of multicomponent printing, electromagnetic waves are guided through the produced functional structure at significantly higher frequencies and with lower losses than in functional structures produced by methods known from the prior art.

[0044] It is conceivable to remove the pattern from the casting mold without leaving any residue.

[0045] Residue-free is preferably understood to mean that the pattern remains in the casting mold for less than 10%, preferably less than 5% or less than 1% of the pattern mass, or that the pattern is completely removed from the molding material.

[0046] The high purity of the pattern, i.e. a pattern in which more than 90%, preferably more than 95%, in particular more than 99% of the mass of the pattern consists of pure material, advantageously enables a demolding which is designed specifically for the pure material. The parameters for demolding, such as temperature or gas pressure, can therefore be precisely adapted to the pure material. This then enables a demolding in which no or only negligible residues of pure material remain in the casting mold.

[0047] Preferably, the slot of the slotted waveguide facilitates the creation of a shape, in particular on the inner side of the slotted waveguide pattern.

[0048] It is preferably provided that regions or the entire surface of the pattern and / or the casting mold and / or the functional structure are smoothed.

[0049] The smoothing can be carried out, for example, by stripping and / or coating, preferably galvanically.

[0050] It can be provided that post-processing is performed in such a way that the pattern, the mold or the functional structure is smoothed in order to improve the high-frequency technical properties of the functional structure.

[0051] The smoothing can be carried out by abrasion, for example by means of a multiphase fluid or a gas with solids.

[0052] Smoothing can be carried out by coating, for example by means of metallization.

[0053] Smoothing can be performed by deformation of the surface or by blasting, for example sandblasting, shot blasting or dry ice blasting.

[0054] Smoothing can be performed at any point in the method.

[0055] Preferably, the slot of the slotted waveguide facilitates smoothing on the inner side of the slotted waveguide.

[0056] It is preferably proposed that at least one of the following steps is carried out before or during the filling of the melt:

[0057] - evacuate the mold;

[0058] -Fill the casting mould with protective gas.

[0059] Preferably, the gap of the slotted waveguide facilitates the filling of the melt or facilitates the melt to enter the inner side of the slotted waveguide.

[0060] Filling the casting mold with protective gas can be carried out at a gas pressure of about 2 bar. It can also be provided that the casting mold is purged several times before or during the filling of the melt with protective gas.

[0061] Advantageously, no residues remain in the casting mold or in the mold cavity. More sophisticated structures are possible, and there are no or only a certain number of shrinkage cavities, so that there is no functional impairment of the functional structure. Reactive metals can also be processed because there is no oxygen in the casting mold.

[0062] The protective gas is, for example, an inert gas such as argon.

[0063] It can be provided that pressure is exerted on the melt after or during the filling of the melt.

[0064] It is conceivable that the molding material comprises either gypsum and / or salt and / or sand and / or concrete and / or silicon or one or more phosphate-binding substances.

[0065] It is also conceivable that the melt or the functional structure comprises one or more of aluminum, copper, steel, silver, tin, zinc, bronze, brass, gold, titanium and / or magnesium.

[0066] Preferably, the functional structure is a high-frequency line, particularly preferably a slotted waveguide, or an antenna, particularly a horn antenna, a helical antenna or a waveguide slot antenna, or a filter or a resonator or a coupler or other passive high-frequency component, or comprises one or more of these components.

[0067] The invention also relates to a high-frequency functional structure which is produced partly or completely by means of the method according to the invention.

[0068] Casting methods have several advantages over metal printing in particular. Significantly more metal can be processed. More complex and finer structures are possible. Surface roughness is lower. The material quality is higher, since there is solid material in the end product.

[0069] By using a high-purity material, the pattern is preferably better formed in the molding material or the embedding compound. The surface quality and roughness are preferably significantly improved again.

[0070] The functional structure is preferably monolithic and metallic.

[0071] It is conceivable that the non-radiating openings of the slotted waveguide are arranged at a pitch smaller than the guided wavelength along the propagation direction and / or that the size of the non-radiating openings is smaller than half the guided wavelength.

[0072] Furthermore, it can be provided that, when removing the patterned support structure, the support material is washed away through the non-radiating openings of the slotted waveguide, or the removal is at least facilitated thereby.

[0073] In a further development of the invention, it is provided that when the pattern is introduced into the molding material and shaped, the molding material reaches into the interior of the slotted waveguide through the non-radiating openings of the pattern, or thereby facilitates the entry.

[0074] During demolding of the molding material to be removed, provision can be made for it to escape through the non-radiating openings of the slotted waveguide, or for its escape to be at least facilitated thereby.

[0075] It is also conceivable to apply the gate structure required for metal casting at locations of the high-frequency component at which no relevant high-frequency functionality is required, and in particular on the outside of the waveguide or of the waveguide component.

[0076] It should be pointed out here that the terms "a" and "an" do not necessarily refer to exactly one of the elements, even if this is a feasible embodiment, but can also represent multiple elements. Similarly, the use of the plural also includes the presence of the elements involved in the singular, and conversely the singular also includes multiple elements of the elements involved. In addition, all the features of the present invention described herein can be claimed in any combination with each other or in isolation from each other.

[0077] It should also be noted that the term "waveguide" includes not only the waveguide itself, but also high-frequency components, such as antennas, having such a waveguide. Therefore, the present invention is not limited to the production of waveguides themselves, but also includes the production of structures having at least one waveguide.

[0078] Further advantages, features and effects of the present invention are apparent from the following description of preferred exemplary embodiments. DETAILED DESCRIPTION

[0079] One embodiment relates to a slotted waveguide produced by means of a method according to the invention.

[0080] A slotted waveguide is a box-shaped conductor with slots at the side walls.

[0081] First, a pattern of a slotted waveguide is made, wherein more than 99 mass percent of the pattern is composed of pure wax.

[0082] The pattern is produced, for example, by a 3D printing method. For technical reasons, in 3D printing, it is necessary to support the unfinished areas by support structures according to the geometric structure of the printed product.

[0083] The support structure can now be designed such that it is partially used as a casting system or is also partially removed before the pattern is shaped.

[0084] In the example described, parts of the support structure are used as casting systems, and other parts are free-cleaned. Here, those parts that are free-cleaned are composed of materials that are soluble in methanol.

[0085] Free cleaning can be performed, for example, by immersing the printed product in methanol and dissolving a portion of the support structure consisting of a material soluble in methanol.

[0086] The pattern with the casting system can be called a model.

[0087] Now, the model is placed in a molding material with plaster or gypsum and shaped. When the plaster is shaped, the plaster can enter the inner cavity of the slotted waveguide more easily through the slit of the slotted waveguide.

[0088] The plaster is now allowed to harden. Hardening can be achieved by leaving it to dry.

[0089] The hardening can also be carried out by burning the plaster.

[0090] After hardening or before or during burning, the model is demoulded from the plaster. To this end, the plaster and the model are brought to a temperature at which the wax melts, for example above 40°C.

[0091] The model then melts and the wax flows out of the plaster and leaves the cavity. The gaps in the slotted waveguide facilitate the wax to escape from the inner region of the model.

[0092] The mold cavity is then thoroughly purged with argon gas, so that air or oxygen is displaced from the mold cavity. Previously, the mold cavity could be smoothed by blowing it out with a gas doped with wear-resistant particles.

[0093] The aluminum alloy melt is then injected into the mold cavity partially surrounded by the plaster.

[0094] Then, the melt is loaded with a pressure of about 2 bar so that the melt is squeezed into the entire cavity. The gap of the slotted waveguide is conducive to the melt entering the interior of the slotted waveguide.

[0095] After the melt cools, the plaster mold is destroyed and the cooled melt is demolded. During demolding, the gap of the slotted waveguide facilitates the removal of the plaster mold from the interior of the slotted waveguide.

[0096] The casting system is then removed from the functional structure.

[0097] The functional structure is subsequently reworked in such a way that the surface is smoothed.

Claims

1. A method for producing a functional structure for high-frequency technology, the method comprising the following steps: - manufacturing the functional structure; - placing the pattern into a molding material and shaping it; - demoulding the pattern from the molding material so as to produce a casting mold; - filling the melt into the casting mold; - demoulding the solidified melt, It is characterized in that More than 90%, preferably more than 95%, in particular more than 99% by mass of the pattern consists of pure material.

2. A method for producing a functional structure for high-frequency technology, the method comprising the following steps: - manufacturing the functional structure; - placing the pattern into a molding material and shaping it; - demoulding the pattern from the molding material so as to produce a casting mold; - filling the melt into the casting mold; - demoulding the solidified melt, It is characterized in that The functional structure and / or the pattern is a slotted waveguide and / or a waveguide with non-radiating openings and / or high-frequency components derived therefrom.

3. The method according to claim 1, characterized in that: The method also has the features of the characterizing part of claim 2 .

4. The method according to any one of the preceding claims, characterized in that The pattern is produced by means of an additive method, preferably a multi-component printing method, preferably a multi-nozzle printing method.

5. The method according to any one of the preceding claims, characterized in that The pattern is produced by means of an additive method, preferably a stereolithographic, synthetic resin-based and / or filament extrusion printing method and / or selective laser sintering.

6. The method according to any one of the preceding claims, characterized in that A support structure is arranged at the pattern, wherein the support structure is at least partially composed of a material different from the material of the pattern or composed of the same material as the pattern.

7. The method according to claim 6, characterized in that Before the pattern is placed in the molding material and shaped, the supporting structures of the pattern required for additive manufacturing are removed.

8. The method according to claim 6 or 7, characterized in that: The support structure is washed off with the aid of a solvent, preferably isopropanol or methanol.

9. The method according to any one of the preceding claims, characterized in that The pure material is wax, plastic, tin or lead, or other metal.

10. The method according to any one of the preceding claims, characterized in that The pattern is demoulded from the casting mold without any residue.

11. The method according to any one of the preceding claims, characterized in that Regions or the entire surface of the pattern and / or of the casting mold and / or of the functional structure are smoothed.

12. The method according to claim 11, characterized in that The smoothing is carried out by ablation and / or by coating, preferably electroplating.

13. The method according to any one of the preceding claims, characterized in that At least one of the following steps is performed before or during the filling of the melt: - evacuating the casting mold; - Filling the casting mould with protective gas.

14. The method according to any one of the preceding claims, characterized in that After or during the filling of the melt, pressure is exerted on the melt.

15. The method according to any one of the preceding claims, characterized in that The molding material comprises either gypsum, salt, sand, concrete, silicon or one or more phosphate-binding substances.

16. The method according to any one of the preceding claims, characterized in that The melt or the functional structure comprises aluminum, copper, steel, silver, tin, zinc, bronze, brass, gold, titanium and / or magnesium or another metal.

17. The method according to any one of claims 2 to 16, characterized in that The non-radiating openings of the slot waveguide are arranged at a pitch smaller than the guide wavelength along the propagation direction, and the size of the non-radiating openings is smaller than half of the guide wavelength.

18. The method according to any one of claims 2 to 17, characterized in that When removing the support structure of the pattern, the support material is washed away through the non-radiating openings of the slotted waveguide or the removal is facilitated thereby.

19. The method according to any one of claims 2 to 18, characterized in that When the pattern is placed in the molding material and shaped, the molding material reaches the interior of the slotted waveguide through the non-radiating openings of the pattern of the slotted waveguide or facilitates the entry.

20. The method according to any one of claims 2 to 19, characterized in that When the molding material to be removed is demolded, it escapes through the non-radiating openings of the slotted waveguide or its escape is facilitated thereby.

21. The method according to any one of the preceding claims, characterized in that The gate structures required for metal casting are arranged at locations of the high-frequency component at which no relevant high-frequency functionality is required and in particular on the outside of the waveguide or of the waveguide component.

22. The method according to any one of the preceding claims, characterized in that The functional structure is a high-frequency line, in particular a waveguide, preferably a slotted waveguide, or an antenna, in particular a horn antenna, a helical antenna or a waveguide slot antenna, or a filter or a resonator or a coupler or other passive high-frequency component, or includes one or more of these components.

23. A functional structure of high-frequency technology produced partly or completely by means of a method according to any of the preceding claims.