Waveguide fence support

Abstract

A method of manufacturing a waveguide for a radar system includes forming an additive manufacturing build of the waveguide by forming an initial layer, followed by forming a series of build layers on the initial layer in a build direction from the initial layer to a final layer, wherein forming the series of build layers includes forming an overhanging feature supported by supports formed in the series of build layers.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Patent Application No. 17 / 176,115, filed February 15, 2021, the disclosure of which is incorporated by reference in its entirety herein.

[0002] Statement on Federally Sponsored Research This invention was made with Government support under Government Contract W31P4Q-15-C-0022 awarded by the U.S. Army Contracting Command, Redstone. The Government has certain rights in this invention.

[0003] The present disclosure relates generally to additive manufacturing, and in particular to additive manufacturing for waveguides such as those used in radar systems. [Background technology]

[0004] Radar systems use waveguides to guide electromagnetic (EM) wave energy. A waveguide horn may introduce EM waves or receive EM waves to or from the air. A typical waveguide horn may contain fence features that tune or otherwise modify the waveguide or horn structure for better electrical properties. These fence features are very difficult to fabricate, usually requiring casting or highly complex brazing.

[0005] Recently, additive manufacturing has been shown to produce radio frequency (RF) waveguide and horn structures at frequencies below C-band. Many waveguide geometries contain special features to tune the electrical response, but the geometries are difficult to machine and braze. For example, some radar systems have fence geometries to suppress higher order electrical modes.

[0006] The prior art has been deemed satisfactory for its intended use. However, there continues to be a need for improved systems and methods for creating fence features in waveguide systems. The present disclosure provides a solution to this need. Summary of the Invention

[0007] A method of manufacturing a waveguide for a radar system includes forming an additive manufacturing build of the waveguide by forming an initial layer, followed by forming a series of build layers on the initial layer in a build direction from the initial layer to the final layer. Forming the series of build layers includes forming an overhanging feature supported by supports formed in the series of build layers. Forming the additive manufacturing build includes forming an AlSi 10 The method can include forming an additive manufacturing build of a Mg material. The initial layer can be formed on a build plate, and forming the support can be done without fastening the overhanging feature to the build plate.

[0008] Forming the support can include building up the support in successive layers from an initial support layer to a final support layer that contacts the first layer of the overhanging feature. The final support layer can contact the first layer of the overhanging feature at a plurality of spaced apart points. The initial support layer can contact a lower layer of the additive manufacturing build at a plurality of spaced apart points. Forming the support can include forming the support offset from adjacent features.

[0009] The support can include a plurality of upper notch layers underlying the final support layer. The upper notch layers and the final support layer can form a plurality of upper notches between the support and the overhanging feature. Each of the upper notches can be V-shaped and narrower away from the overhanging feature. Forming the support can also include forming a plurality of lower notch layers above the initial support layer. The lower notch layers and the initial support layer can form a plurality of lower notches between the lower layer and the support. Each of the lower notches can be V-shaped and narrower away from the lower layer. Forming the support can include forming a support having a plurality of through holes therethrough configured to facilitate fracture of the support.

[0010] The additive manufacturing build can be a radar waveguide and the overhanging feature can be a fence that crosses an electromagnetic (EM) waveguide that extends in the build direction. The fence can be oriented 90 degrees perpendicular to the sidewall of the EM waveguide and the build direction. The fence and EM waveguide can be one of a plurality of fences and individual EM waveguides formed in the additive manufacturing build, and the fences and EM waveguides can be arranged together in a waveguide configuration. Each EM waveguide can include three posts that support the individual fences, and the support can be one of four supports spaced apart by the posts.

[0011] The method can include removing the support from the additively manufactured build, where removing the support from the additively manufactured build can include breaking a contact point between the support and the additively manufactured build, where the contact point is between a notch formed in the support. Removing the support from the additively manufactured build can also include a manual deburring process. The manual deburring process can include removing surface roughness from the contact point between the support and the additively manufactured build after removing the support to match or exceed the smoothness of the remaining additively manufactured build away from the contact point.

[0012] A method of manufacturing a waveguide for a radar system can include forming a non-additively manufactured waveguide, including forming a support between an overhanging feature that intersects an electromagnetic (EM) waveguide and a surface of the waveguide, and removing the support from the waveguide.

[0013] These and other features of the subject disclosed systems and methods will become readily apparent to those skilled in the art from the drawings taken in conjunction with the following detailed description.

[0014] Embodiments thereof are described in detail herein with reference to specific figures so that those skilled in the art to which the subject disclosure pertains can readily understand, without undue experimentation, how to make and use the devices and methods of the subject disclosure. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a side perspective view of an embodiment of an additive manufacturing construction constructed in accordance with the present disclosure, showing a waveguide. [Diagram 2] FIG. 2 is a top perspective view of the waveguide of FIG. 1 showing an overhanging feature. [Diagram 3] FIG. 4 is an enlarged schematic perspective view of the overhang feature of FIG. [Figure 4] FIG. 4 is a schematic perspective view of the overhanging feature of FIG. 3, showing the support included under the overhanging feature during additive manufacturing of the build. [Diagram 5] FIG. 5 is an enlarged schematic view of the support of FIG. 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Reference is now made to the drawings, in which like reference numerals identify like structural features or aspects of the subject disclosure. For purposes of explanation and illustration, without limitation, a partial view of an embodiment of a system according to the present disclosure is shown in FIG. 1 and generally designated by reference numeral 100. Other embodiments of systems according to the present disclosure, or aspects thereof, are shown in FIGS. 2-4, as discussed below. The systems and methods described herein can be used to create fence shapes in waveguide systems.

[0017] A method of manufacturing a waveguide 100 for a radar system is disclosed. The methods described herein are described with respect to an additively manufactured waveguide 100, however, one of ordinary skill in the art will appreciate that at least portions of the following methods can be used to manufacture non-additively manufactured waveguides, or any additively manufactured construction having overhanging features.

[0018] As shown in FIGS. 1-2, an additive manufacturing build (e.g., a waveguide 100) can be formed. An initial layer 102 can be formed (e.g., on a build plate), followed by a series of build layers formed on the initial layer in a build direction (e.g., arrow 104) from the initial layer 102 toward the final layer 110. Forming the series of build layers can include forming an overhanging feature 106 supported by supports 108 (shown in FIG. 4). The overhanging feature 106 can be a fence (e.g., to adjust or improve electrical properties of the waveguide 100) that crosses an electromagnetic (EM) waveguide 130. The waveguide 130 extends in the build direction 104. The supports 108 can be formed in the series of build layers, without fastening the overhanging 106 feature to a build plate. The waveguide 100 can be formed by laser powder bed fusion bonding, e.g., AlSi 10 It can be formed by using a powder layer containing Mg.

[0019] 2-4, the fence 106 may be oriented at 90 degrees perpendicular to the sidewall 132 of the EM waveguide 130 and the build direction 104. The fence 106 and EM waveguide 130 may be one of a plurality of fences 106 and individual EM waveguides 130 formed in the waveguide 100, and each fence 106 and EM waveguide 130 may be identical or similar to one another. In an embodiment, the fences 106 and EM waveguides 130 may be arranged together in a waveguide configuration, as shown in the completed waveguide 100 of FIGS. 1-2. Each EM waveguide 130 may include three posts 134 supporting each individual fence 106, for example for C-band waveguiding, and the supports 108 may be one of any number of supports 108 spaced apart from one another by the posts 134. Although four supports 108 are shown in FIG. 4, it should be appreciated that any number of supports 108 may be used depending, for example, on the total number of struts 134 used in the waveguide 100.

[0020] The supports 108 can be built in successive layers, from the initial support layer 112 to the final support layer 114, which contacts the first layer 116 of the overhanging feature 106. The initial support layer 112 and the final support layer 114 can contact the bottom layer 118 of the waveguide and the first layer 116 of the fence 106 at multiple spaced apart points (contact points 136), respectively. Because the supports 108 contact the waveguide 100 at multiple points, removal of the supports after construction can be facilitated and the surface finish can be improved, as described below. Similarly, the supports 108 can be built offset from adjacent vertical features (e.g., sidewalls 132 and / or posts 134) to avoid additional contact points being formed. If the supports 108 were built directly adjacent to the vertical subfeatures, the vertical subfeatures would exhibit roughness and burrs. Thus, the offset prevents such roughness and burrs, improving the surface quality during construction.

[0021] 3-5, the support 108 can include a plurality of upper notch layers 120 underlying the final support layer 114. The upper notch layers 120 and the final support layer 114 can form a plurality of upper notches 122 between the support 108 and the overhanging feature 106. Each of the upper notches 120 can be V-shaped and narrower away from the overhanging feature 106. Similarly, a plurality of lower notch layers 124 can be formed above the initial support layer 112. Accordingly, a plurality of lower notches 126 are formed between the lower layer 118 and the support 108. Each of the lower notches 126 can also be V-shaped and narrower away from the lower layer 118. Additionally, the support 108 includes a plurality of through holes 128 defined therethrough configured to facilitate fracturing the support 108 when removing the support 108 after completion of the additive manufacturing build.

[0022] After construction of the waveguide 100 is complete, the support 108 can be removed from the waveguide 100. Removing the support 108 can include breaking the contact points 136 between the support 108 and the waveguide 100 (e.g., at the interfaces between the support 108 and the underlayer 118 and the overhanging feature 106). The contact points 136 are between the notches 122, 126. Removing the support 108 can also include further surface treatment, such as a manual deburring process. The manual deburring process can include removing surface roughness from the contact points (e.g., the contact points 136) between the support 108 and the waveguide 100 after removal of the support 108. The shape of the support 108 can be such that when removed for deburring, the surface of the contact points 136 is equal to or exceeds the smoothness of the remaining waveguide 100 away from the contact points.

[0023] Conventional waveguides are typically cast designs or brazed requiring challenging high temperature manufacturing characteristics, increasing lead times and costs and potentially introducing program risks. Additionally, creating fence features in cast or brazed waveguides can be quite complex to construct and surface finish, potentially compromising the surface quality of the fence structure. As discussed above and shown in the drawings, the methods and systems of the present disclosure provide improved fence geometries with surface roughnesses of less than 300 microinches Ra. While the apparatus and methods of the subject disclosure have been illustrated and described, those skilled in the art will readily recognize that variations and / or modifications may be made therein without departing from the scope of the subject disclosure.

Claims

1. 1. A method of manufacturing a waveguide for a radar system, comprising the steps of: forming an additive manufacturing build of a waveguide by forming an initial layer, followed by forming a series of build layers on the initial layer in a build direction from the initial layer toward a final layer, wherein forming the series of build layers includes forming an overhanging feature supported by supports formed in the series of build layers; Including, the additive manufacturing build is a radar waveguide and the overhanging feature is a fence that crosses an electromagnetic (EM) wave path extending in the build direction.

2. The method of claim 1 , wherein forming the support includes building up the support in successive layers from an initial support layer to a final support layer that contacts an initial layer of the overhanging feature.

3. The method of claim 2 , wherein the final support layer contacts the initial layer of the overhanging feature at a plurality of spaced apart points.

4. The method of claim 3 , wherein the support includes a plurality of upper notch layers underlying the final support layer, the upper notch layers and the final support layer forming a plurality of upper notches between the support and the overhanging feature.

5. The method of claim 4 , wherein each of said upper notches are all V-shaped and narrow away from said overhanging feature.

6. 3. The method of claim 2, wherein the initial support layer contacts an underlying layer of the additive manufacturing build at a plurality of spaced apart points.

7. 7. The method of claim 6, wherein forming the support includes forming a plurality of lower notch layers above the initial support layer, the lower notch layers and the initial support layer forming a plurality of lower notches between the lower layer and the support.

8. The method of claim 7 , wherein each of said lower notches are all V-shaped and narrow away from said lower layer.

9. The method of claim 1 , wherein forming the support comprises forming the support with a plurality of through holes therethrough configured to facilitate fracturing the support.

10. The method of claim 1 , wherein forming the supports comprises forming the supports offset from adjacent features.

11. The method of claim 1 , wherein the fence is oriented 90 degrees perpendicular to a sidewall of the EM waveguide and the build direction.

12. 2. The method of claim 1 , wherein the fence and EM waveguide are one of a plurality of fences and individual EM waveguides formed in the additive manufacturing build, and the fences and EM waveguides are arranged together in a waveguide configuration.

13. 13. The method of claim 12, wherein each EM waveguide includes three posts supporting the respective fence, the support being one of four supports spaced apart by the posts.

14. The method of claim 1 , further comprising removing the support from the additive manufacturing build.

15. 15. The method of claim 14, wherein removing the support from the additive manufactured build comprises breaking a contact point between the support and the additive manufactured build, the contact point being between a notch formed in the support.

16. 16. The method of claim 15, wherein removing the support from the additively manufactured build comprises a manual deburring process, the manual deburring process comprising removing surface roughness from a contact point between the support and the additively manufactured build after removing the support to match or exceed a smoothness of the remaining additively manufactured build away from the contact point.

17. Forming the additive manufacturing build comprises forming an AlSi １０ The method of claim 1 comprising forming the additive manufacturing build of a Mg material.

18. The method of claim 1 , wherein forming the initial layer on a build plate and forming the supports occurs without fastening the overhanging features to the build plate.

19. 1. A method of manufacturing a waveguide for a radar system, comprising the steps of: forming a non-additively manufactured waveguide, the forming including forming a plurality of supports between an overhanging feature that intersects an electromagnetic (EM) waveguide and a surface of the waveguide; removing the support from the waveguide, the removing the support from the waveguide including breaking a contact point between the support and the waveguide, the contact point being between a notch formed in the support; manual deburring of the waveguide, the manual deburring including removing surface roughness from the contact point between the support and the waveguide after removing the support to match or exceed the smoothness of the remaining waveguide away from the contact point; The method comprising:

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