A 3D printing method for a high aspect ratio titanium alloy four-arm helical satellite antenna

Abstract

This invention relates to a 3D printing method for a high aspect ratio titanium alloy quad-helical satellite antenna. The antenna is made of TC4 alloy with an aspect ratio of 6 or higher. The four helical arms have an inner and outer helical structure with an arm thickness of 1.5~2.5mm, and the angle between the inner and outer helical structures and the horizontal plane is 50° or less. The method includes the following steps: preheating treatment, excess printing, and annealing post-treatment; thus, a high-quality, defect-free high aspect ratio quad-helical satellite antenna is manufactured using 3D printing. This invention achieves integrated fabrication of high aspect ratio thin-walled complex structure antennas, resulting in uniform microstructure, good vibration resistance and thermal cycling performance. It solves the problem of difficulty in manufacturing thin-walled helical structures using traditional machining, as well as the challenges of high stress and easy cracking defects in high aspect ratio titanium alloy laser printing. It is low-cost, quick, and produces high-quality prints, and can be widely applied to the near-net-shape manufacturing of complex irregular-shaped satellite antenna products.

Description

Technical Field

[0001] This invention relates to the fields of titanium alloys and 3D printing technology, specifically to a 3D printing method for a high aspect ratio titanium alloy four-arm helical satellite antenna. Background Technology

[0002] Over the past decade, the demand for faster data rates has been steadily increasing, leading to the rapid development of 5G / 6G communications, the Internet of Things (IoT), and small satellite communications. In satellite communications, antenna performance directly impacts signal transmission quality and coverage. With the advent of 5G and the evolution of communication systems towards millimeter waves and higher frequencies, antennas will be required to have higher gain, wider bandwidth, and lower power consumption. These requirements necessitate complex antenna structures, high integration, lightweight designs, and miniaturization, putting pressure on existing manufacturing processes.

[0003] Spiral antennas can carry high-speed data transmission and have advantages such as broadband performance, high gain, and standardization, making them widely used in broadband satellite communications. Small, high-aspect-ratio quad-helical antennas are a new type of high-performance communication antenna. However, current machining processes are limited by the complex geometry, making it difficult to meet the requirements of next-generation structural designs. Additive manufacturing (AM) technology has brought new opportunities to antenna manufacturing, enabling certain 3D structural designs. Currently, most spiral antennas use lightweight, high-strength metal materials such as aluminum alloys and titanium alloys. Compared to aluminum alloys, titanium alloys have higher strength and better environmental resistance, making them an ideal material for small, quad-helical antennas. However, the quality of small, complex antenna structures is difficult to guarantee during 3D printing, especially when the printing height is greater than five times the printing width, which can easily lead to stress accumulation and cracking. Therefore, a new 3D printing strategy must be found to reliably manufacture high-aspect-ratio, thin-walled spiral titanium alloy structures. Summary of the Invention

[0004] To address the manufacturing challenges of titanium alloy quad-arm helical antennas, this invention proposes a 3D printing method for titanium alloy quad-arm helical satellite antennas with a large aspect ratio. This method effectively solves the requirements of satellite antenna products for titanium alloys with a large aspect ratio and thin-walled helical structure. The manufacturing process is simple and industrializable.

[0005] This invention discloses a 3D printing method for a high aspect ratio titanium alloy quad-helical satellite antenna. The high aspect ratio titanium alloy quad-helical satellite antenna is made of TC4 alloy with an aspect ratio greater than or equal to 6. The four helical arms have an inner and outer helical structure with an arm thickness of 1.5~2.5mm. The angle between the inner and outer helical structures and the horizontal plane is 50° or less. In the quad-helical arms, there are hollow spaces between adjacent helices and between the helices and the central axis.

[0006] The 3D printing method includes the following steps:

[0007] Step 1: Preheating

[0008] The TC4 powder raw material and the substrate are preheated separately, wherein the powder preheating temperature is A and the substrate preheating temperature is B; wherein A is 200~550℃, preferably 400~550℃, and B is 300~600℃, preferably 500~600℃, and B is greater than A.

[0009] Step 2: Print the remaining amount

[0010] Set the printing allowance, and use the contour spiral scanning strategy for SLM printing to obtain the printed part;

[0011] The setting of the printing allowance is based on the product structure to set the printing allowance of the outer spiral structure, where the wall thickness of the outer spiral structure of the product is X, the designed printing wall thickness is Y, and the printing allowance Z=YX, satisfying Z / X<20%;

[0012] In step two, the SLM printing process uses the following parameters: layer thickness 0.02~0.06mm, scanning speed 800~1800mm / s, scanning spacing 0.04~0.1mm, and laser power 250~500W.

[0013] Step 3: Post-processing

[0014] The printed parts are annealed, and the annealed samples are then polished and sandblasted to obtain high-quality antenna products.

[0015] As a preferred embodiment, the present invention provides a 3D printing method for a titanium alloy quad-arm spiral satellite antenna with a high aspect ratio, wherein the spiral has an aspect ratio greater than or equal to 6 and a diameter less than or equal to 40 mm, preferably 15-40 mm, and a height greater than or equal to 90 mm, preferably 90-240 mm.

[0016] As a preferred embodiment, the present invention provides a 3D printing method for a high aspect ratio titanium alloy quad-helical satellite antenna, wherein the angle between the inner helical structure and the horizontal plane is 45°~50°, and the angle between the outer helical structure and the horizontal plane is 35°~45°.

[0017] As a preferred embodiment, in the present invention, a method for 3D printing a high aspect ratio titanium alloy four-arm spiral satellite antenna, in step one, the powder raw material is TC4 powder prepared by gas atomization process, and the powder particle size is 15-53μm.

[0018] This invention discloses a 3D printing method for a high aspect ratio titanium alloy four-arm helical satellite antenna. In step one, the preheating treatment involves first heating the powder material in a drying oven to temperature A, then loading it into the powder hopper of an SLM printing device. After evacuation, an inert gas is introduced, and the substrate is then heated to temperature B using the device's built-in heating device. Here, A = BC, and C is 30~100℃, preferably 50~100℃. Given that titanium alloys are highly sensitive to thermal stress, and that residual stress is mainly caused by uneven cooling shrinkage, setting a high preheating temperature ensures sufficient shrinkage during the powder melting and cooling process, avoiding the formation of voids and cracks. Simultaneously, the substrate temperature is slightly higher than the powder material temperature, reducing the risk of warping deformation.

[0019] The present invention discloses a 3D printing method for a high aspect ratio titanium alloy four-arm spiral satellite antenna, characterized in that, in step two, the contour spiral scanning strategy is to use a laser to scan and form the shape layer by layer along the contour ring of the cross section from the outside to the inside towards the center.

[0020] Preferably, in step two, the SLM printing process uses the following parameters: layer thickness 0.03~0.05mm, scanning speed 1200~1800mm / s, scanning spacing 0.06~0.1mm, and laser power 320~400W.

[0021] The present invention discloses a 3D printing method for a high aspect ratio titanium alloy four-arm spiral satellite antenna. In step three, the annealing treatment is carried out at 700~850℃ for 0.5~2h and then cooled in the furnace.

[0022] Preferably, in step three, the annealing process is performed by holding at 780~850℃ for 50~75 minutes and then cooling in the furnace.

[0023] The present invention discloses a 3D printing method for a high aspect ratio titanium alloy four-arm spiral satellite antenna, characterized in that, in step three, the grinding is performed by using an electric grinding pen to grind the outer spiral structure, grinding away the printing allowance to the product size.

[0024] The high aspect ratio titanium alloy quad-arm spiral satellite antenna obtained by this invention is particularly suitable for use as a communication antenna for high-precision satellite navigation.

[0025] Principles and advantages

[0026] This invention discloses a 3D printing method for a high aspect ratio titanium alloy four-armed spiral satellite antenna. The method presents two main challenges: First, the four-armed spiral structure is centrally symmetrical, with all arms positioned on the same vertical plane from bottom to top, making it difficult to set a support starting point during 3D printing. The thin-walled spiral structure is prone to deformation, and its shape and dimensions are difficult to control. Second, the high aspect ratio spiral structure results in significant radial thermal shrinkage during laser melting of the metal powder, leading to large thermal stress and cracking defects. Furthermore, the thin spiral antenna arms cause uneven stress distribution, potentially resulting in product breakage.

[0027] This invention proposes a "preheating treatment-excess printing-post-processing" printing manufacturing method. By coordinating the design of a preheating scheme to reduce thermal stress, a contour spiral scanning scheme, and an annealing scheme, and the excess printing process to ensure product size, it achieves defect-free, high-reliability, and high-performance manufacturing of titanium alloy quad-arm spiral satellite antennas with large aspect ratios, meeting the requirements of satellite-borne environments.

[0028] The specific principle is as follows: To achieve defect-free, high-quality printing of titanium alloy spiral antennas with a height-to-diameter ratio > 6, this invention addresses residual stress by first reducing the temperature difference between the laser-melted powder and the unmelted powder and substrate through preheating of the printing platform and raw material powder, thereby reducing thermal stress. The contour spiral scanning scheme involves the laser scanning layer by layer from the outside in along the contour. The internal stress direction of the scanning line is divergent, reducing stress concentration. Simultaneously, the spiral scanning path is spherical, without sharp corners, and the stress is distributed across the entire curved surface, significantly reducing stress concentration and mitigating the risk of warping and cracking. Post-printing heat treatment abandons the complex solution-aging process of titanium alloys, employing a simple medium-high temperature annealing process to greatly reduce residual stress while achieving a good strength-plasticity match. This ensures good structural strength of the printed four-arm spiral thin-walled structure during polishing and guarantees the reliability of the antenna mounting test performance. From the perspective of controlling product dimensional accuracy, and addressing the challenges of small inner and outer spiral angles in four-armed spirals that cannot be pre-supported, as well as the problem of thin-walled structures being prone to deformation, a printing allowance is first set to ensure the integrity of the formed structure. At the same time, contour spiral scanning is used to reduce the stress at the spiral corners and avoid the risk of stress cracking during subsequent grinding, thus achieving high-precision forming of thin-walled four-armed spirals.

[0029] Compared with existing methods, the advantages of the present invention are:

[0030] 1) The present invention provides a 3D printing method for a high aspect ratio titanium alloy four-arm spiral satellite antenna, which solves the problem that the four-arm spiral structure cannot be directly processed and manufactured by CNC. The process is based on laser selective melting, which is simple, easy to operate, and has low preparation cost. It is suitable for industrialization and meets the needs of aerospace cost reduction and efficiency improvement.

[0031] 2) The preheating treatment-excess printing-post-processing process of the present invention solves the problem of high stress and easy cracking defects in the 3D printing of titanium alloy four-arm spiral structures with large aspect ratio, and obtains defect-free high-quality titanium alloy four-arm spiral antenna products.

[0032] 3) The present invention provides a 3D printing method for a high aspect ratio titanium alloy four-armed spiral satellite antenna. In view of the problems of thin-walled structure of four-armed spiral and small inclination angle of inner and outer spiral, it is difficult to pre-support. The developed margin printing and contour spiral scanning scheme ensures the dimensional accuracy of the four-armed spiral structure and provides a new idea for the development of supportless printing forming in 3D printing. Attached Figure Description

[0033] Figure 1 This is a titanium alloy four-arm helical satellite antenna structure with a height-to-diameter ratio of 7.2 obtained in Embodiment 1 of the present invention.

[0034] Figure 2 The above is a titanium alloy four-arm helical satellite antenna structure with a height-to-diameter ratio of 7.2 printed as Comparative Example 1 of this invention. Detailed Implementation

[0035] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0036] Example 1

[0037] In this embodiment, the 3D printing method for the high aspect ratio quad-helical satellite antenna is carried out according to the following steps:

[0038] Step 1: Preheating

[0039] Atomized TC4 powder with a particle size of 15-53μm was placed in a vacuum drying oven and heated to 500℃. Then it was loaded into the powder hopper of the SLM printing equipment. After evacuation, inert gas was introduced, and the substrate was heated to 550℃ using the equipment's built-in heating device.

[0040] Step 2: Print the remaining amount

[0041] The designed four-arm helical antenna has a helix diameter of 25mm and a height of 180mm. It features an inner and outer helix structure with an arm thickness of 2mm. The inner helix has a 45° angle with the horizontal plane, while the outer helix has a 35° angle. Printing allowances were set based on the angles of the inner and outer helical structures to the horizontal plane. The outer helix had a wall thickness of 2.3mm and a printing allowance of 0.3mm. SLM printing was performed using a contour helical scanning strategy to obtain the printed part. The laser scanned along the contour ring of the cross-section, layer by layer from the outside inwards towards the center. The printing parameters were: layer thickness 0.03mm, scanning speed 1600mm / s, scanning interval 0.09mm, and laser power 360W.

[0042] Step 3: Post-processing

[0043] The printed parts were annealed, with the annealing process involving holding at 810℃ for 1 hour followed by furnace cooling. After annealing, the outer spiral structure of the sample was polished with an electric grinder to remove the printing excess to the product dimensions. Finally, sandblasting was performed to obtain a high-quality antenna product.

[0044] The titanium alloy quad-arm helical antenna product prepared by the above process is shown below. Figure 1 .

[0045] The obtained titanium alloy quadruped helical antenna was tested. Fluorescence penetrant testing showed no cracks or other defects exceeding the standard. Dimensional testing showed that the dimensions of each part met the product accuracy requirements. The tensile properties of the furnace sample were tested and found to be: tensile strength 1040 MPa, yield strength 948 MPa, and elongation after fracture 15.1%, exceeding the performance level of the existing TC4 report. After 6 cycles of hot vacuum cycling at +85℃ to -85℃ (heating and cooling rate 1℃ / min, extreme temperature residence time 4~6h) and random vibration testing with stress screening in three axial directions at 10~2000Hz for 5min in each axial direction, the product structure remained intact.

[0046] Example 2

[0047] In this embodiment, the 3D printing method for the high aspect ratio quad-helical satellite antenna is carried out according to the following steps:

[0048] Step 1: Preheating

[0049] Atomized TC4 powder with a particle size of 15-53μm was placed in a vacuum drying oven and heated to 420℃. Then it was loaded into the powder hopper of the SLM printing equipment. After evacuation, inert gas was introduced, and the substrate was heated to 500℃ using the equipment's built-in heating device.

[0050] Step 2: Print the remaining amount

[0051] The designed four-arm helical antenna has a helix diameter of 15mm and a height of 97mm. It features an inner and outer helix structure with an arm thickness of 1.8mm. The inner helix has a 48° angle with the horizontal plane, while the outer helix has a 37° angle. Printing allowances were set based on the angles of the inner and outer helical structures to the horizontal plane. The outer helix had a wall thickness of 2mm and a printing allowance of 0.2mm. SLM printing was performed using a contour helical scanning strategy to obtain the printed part. The laser scanned along the contour ring of the cross-section, layer by layer from the outside inwards towards the center. The printing parameters were: layer thickness 0.04mm, scanning speed 1500mm / s, scanning interval 0.08mm, and laser power 380W.

[0052] Step 3: Post-processing

[0053] The printed parts were annealed, with the annealing process involving holding at 780℃ for 1 hour followed by furnace cooling. After annealing, the outer spiral structure of the sample was polished with an electric grinder to remove the printing excess down to the product dimensions. Finally, sandblasting was performed to obtain a high-quality antenna product.

[0054] The titanium alloy quad-arm helical antenna product prepared by the above process is shown below. Figure 1 .

[0055] The obtained titanium alloy quadruped helical antenna product was tested. Fluorescence penetrant testing showed no cracks or other defects exceeding the standard. Dimensional testing showed that the dimensions of each part met the product accuracy requirements. The tensile properties test results of the furnace sample were: tensile strength 1038MPa, yield strength 953MPa, and elongation after fracture 14.3%, exceeding the performance level of the existing TC4 report. After 6 cycles of hot vacuum cycling at +85℃ to -85℃ (heating and cooling rate 1℃ / min, extreme temperature residence time 4~6h), and random vibration testing with stress screening in three axial directions at 10~2000Hz for 5min in each axial direction, the product structure remained intact.

[0056] Example 3

[0057] In this embodiment, the 3D printing method for the high aspect ratio quad-helical satellite antenna is carried out according to the following steps:

[0058] Step 1: Preheating

[0059] Atomized TC4 powder with a particle size of 15-53μm was placed in a vacuum drying oven and heated to 550℃. Then it was loaded into the powder hopper of the SLM printing equipment. After evacuation, inert gas was introduced, and the substrate was heated to 600℃ using the equipment's built-in heating device.

[0060] Step 2: Print the remaining amount

[0061] The designed four-arm helical antenna has a helix diameter of 25mm and a height of 180mm. It features an inner and outer helix structure with an arm thickness of 2mm. The inner helix has a 45° angle with the horizontal plane, while the outer helix has a 35° angle. Printing allowances were set based on the angles of the inner and outer helical structures to the horizontal plane. The outer helix had a wall thickness of 2.3mm and a printing allowance of 0.3mm. SLM printing was performed using a contour helical scanning strategy to obtain the printed part. The laser scanned along the contour ring of the cross-section, layer by layer from the outside inwards towards the center. The printing parameters were: layer thickness 0.03mm, scanning speed 1600mm / s, scanning interval 0.09mm, and laser power 360W.

[0062] Step 3: Post-processing

[0063] The printed parts were annealed, with the annealing process involving holding at 800℃ for 1 hour followed by furnace cooling. After annealing, the outer spiral structure of the sample was polished with an electric grinder to remove the printing excess to the product dimensions. Finally, sandblasting was performed to obtain a high-quality antenna product.

[0064] The titanium alloy quad-arm helical antenna product prepared by the above process is shown below. Figure 1 .

[0065] The obtained titanium alloy quadruped helical antenna product was tested. Fluorescence penetrant testing showed no cracks or other defects exceeding the standard. Dimensional testing showed that the dimensions of each part met the product accuracy requirements. The tensile properties test results of the furnace sample were: tensile strength 1023MPa, yield strength 930MPa, and elongation after fracture 16.2%, exceeding the performance level of the existing TC4 report. After 6 cycles of hot vacuum cycling at +85℃ to -85℃ (heating and cooling rate 1℃ / min, extreme temperature residence time 4~6h), and random vibration testing with stress screening in three axial directions at 10~2000Hz for 5min in each axial direction, the product structure remained intact.

[0066] Example 4

[0067] In this embodiment, the 3D printing method for the high aspect ratio quad-helical satellite antenna is carried out according to the following steps:

[0068] Step 1: Preheating

[0069] Atomized TC4 powder with a particle size of 15-53mm was placed in a vacuum drying oven and heated to 500°C. Then it was loaded into the powder hopper of the SLM printing equipment. After evacuation, inert gas was introduced, and the substrate was heated to 550°C using the equipment's built-in heating device.

[0070] Step 2: Print the remaining amount

[0071] The designed four-arm helical antenna has a helix diameter of 40mm and a height of 240mm. It features an inner and outer helix structure with an arm thickness of 2mm. The inner helix has a 45° angle with the horizontal plane, while the outer helix has a 35° angle. Printing allowances were set based on the angles of the inner and outer helical structures to the horizontal plane. The outer helix had a wall thickness of 2.3mm and a printing allowance of 0.3mm. SLM printing was performed using a contour helical scanning strategy to obtain the printed part. The laser scanned along the contour ring of the cross-section, layer by layer from the outside inwards towards the center. The printing parameters were: layer thickness 0.05mm, scanning speed 1200mm / s, scanning interval 0.06mm, and laser power 400W.

[0072] Step 3: Post-processing

[0073] The printed parts were annealed, with the annealing process involving holding at 780℃ for 2 hours followed by furnace cooling. After annealing, the outer spiral structure of the sample was polished with an electric grinder to remove the printing excess down to the product dimensions. Finally, sandblasting was performed to obtain a high-quality antenna product.

[0074] The titanium alloy quad-arm helical antenna product prepared by the above process is shown below. Figure 1 .

[0075] The obtained titanium alloy quadruped helical antenna was tested. Fluorescence penetrant testing showed no cracks or other defects exceeding the standard. Dimensional testing showed that the dimensions of each part met the product accuracy requirements. The tensile properties of the furnace sample were tested and found to be: tensile strength 1012 MPa, yield strength 906 MPa, and elongation after fracture 15.6%, exceeding the performance level of the existing TC4 report. After 6 cycles of hot vacuum cycling at +85℃ to -85℃ (heating and cooling rate 1℃ / min, extreme temperature residence time 4~6h) and random vibration testing with stress screening in three axial directions at 10~2000Hz for 5min in each axial direction, the product structure remained intact.

[0076] Comparative Example 1 (compared to Example 1)

[0077] The 3D printing method for the four-armed spiral satellite antenna in this comparative example is carried out according to the following steps:

[0078] Step 1: Loading

[0079] Atomized TC4 powder with a particle size of 15-53μm is loaded into the powder hopper of the SLM printer, and after evacuation, inert gas is introduced.

[0080] Step 2: Print

[0081] The designed four-arm helical antenna has a helix diameter of 25mm and a height of 180mm. It features an inner and outer helix structure with an arm thickness of 2mm. The inner helix has a 45° angle with the horizontal plane, while the outer helix has a 35° angle with the horizontal plane. SLM printing was performed using a common parallel grating scanning strategy to obtain the printed part. The printing parameters were: layer thickness 0.03mm, scanning speed 1600mm / s, scanning spacing 0.09mm, and laser power 360W.

[0082] Step 3: Post-processing

[0083] The printed parts were annealed, with the annealing process involving holding at 810℃ for 1 hour followed by furnace cooling. The titanium alloy four-arm helical antenna product prepared using the above process is shown below. Figure 2 At this point, the cracks and breaks are clearly visible.

[0084] The titanium alloy four-arm helical antenna product broke during unloading and handling. The fracture location was the central axis of the helical structure, indicating that it is difficult to achieve high-quality forming of this high aspect ratio titanium alloy product using existing 3D printing technology.

[0085] Comparative Example 2 (compared to Example 1)

[0086] The 3D printing method for the four-armed spiral satellite antenna in this comparative example is carried out according to the following steps:

[0087] Step 1: Preheating

[0088] Atomized TC4 powder with a particle size of 15-53μm was placed in a vacuum drying oven and heated to 500℃. Then it was loaded into the powder hopper of the SLM printing equipment. After evacuation, inert gas was introduced, and the substrate was heated to 550℃ using the equipment's built-in heating device.

[0089] Step 2: Print

[0090] The designed four-arm helical antenna has a helix diameter of 25mm and a height of 180mm. It features an inner and outer helical structure with an arm thickness of 2mm. The inner helix structure forms a 45° angle with the horizontal plane, while the outer helix structure forms a 35° angle with the horizontal plane. A contour helical scanning strategy was used for SLM printing to obtain the printed part. The laser scans along the contour ring of the cross-section, layer by layer from the outside inwards towards the center. The printing parameters are: layer thickness 0.03mm, scanning speed 1600mm / s, scanning spacing 0.09mm, and laser power 360W.

[0091] Step 3: Post-processing

[0092] The printed parts were annealed, with the annealing process involving holding at 810℃ for 1 hour followed by furnace cooling. After annealing, the outer spiral structure of the sample was polished with an electric grinder to remove the printing excess to the product dimensions. Finally, sandblasting was performed to obtain a high-quality antenna product.

[0093] The obtained titanium alloy quadruple spiral antenna product was tested. Fluorescence penetrant testing showed no cracks or other defects exceeding the standard. However, dimensional testing revealed that the outer spiral structure of the quadruple spiral was deformed and did not meet the product accuracy requirements. This was due to the small tilt angle of the outer spiral, the lack of support during printing, and the large shrinkage and thermal stress caused by the thin-walled structure, which made dimensional control difficult.

[0094] Comparative Example 3 (compared to Example 2)

[0095] The 3D printing method for the four-armed spiral satellite antenna in this comparative example is carried out according to the following steps:

[0096] Step 1: Preheating

[0097] Atomized TC4 powder with a particle size of 15-53μm is loaded into the powder hopper of the SLM printing equipment. After evacuation, inert gas is introduced, and then the substrate is heated to 300℃ using the equipment's built-in heating device.

[0098] Step 2: Print the remaining amount

[0099] The designed four-arm helical antenna has a helix diameter of 15mm and a height of 97mm. It features an inner and outer helix structure with an arm thickness of 1.8mm. The inner helix has a 48° angle with the horizontal plane, while the outer helix has a 37° angle. Printing allowances were set based on the angles of the inner and outer helical structures to the horizontal plane. The outer helix had a 2mm wall thickness and a 0.2mm printing allowance. SLM printing was performed using a common parallel grating scanning strategy to obtain the printed part. Printing parameters were: layer thickness 0.04mm, scanning speed 1500mm / s, scanning spacing 0.08mm, and laser power 380W.

[0100] Step 3: Post-processing

[0101] The printed parts were annealed, with the annealing process involving holding at 780℃ for 1 hour followed by furnace cooling. After annealing, the outer spiral structure of the sample was polished with an electric grinder to remove the printing excess to the product dimensions. Finally, sandblasting was performed to obtain the antenna product.

[0102] The resulting titanium alloy four-arm helical antenna had numerous burrs after production, which easily caused defects in the helical structure during polishing, making it difficult to control the dimensions of the helical structure. It even fractured, with the fracture location being the central axis of the helical structure, indicating that existing 3D printing processes are insufficient to achieve high-quality forming of such high aspect ratio titanium alloy products.

[0103] Comparative Example 4

[0104] The 3D printing method for the four-armed spiral satellite antenna in this comparative example is carried out according to the following steps:

[0105] Step 1: Preheating

[0106] Atomized TC4 powder with a particle size of 15-53μm was placed in a vacuum drying oven and heated to 420℃. Then it was loaded into the powder hopper of the SLM printing equipment. After evacuation, inert gas was introduced, and the substrate was heated to 500℃ using the equipment's built-in heating device.

[0107] Step 2: Print the remaining amount

[0108] The designed four-arm helical antenna has a helix diameter of 15mm and a height of 97mm. It features an inner and outer helix structure with an arm thickness of 1.8mm. The inner helix has a 48° angle with the horizontal plane, while the outer helix has a 37° angle. Printing allowances were set based on the angles of the inner and outer helical structures to the horizontal plane. The outer helix had a wall thickness of 2mm and a printing allowance of 0.2mm. SLM printing was performed using a common parallel grating scanning strategy to obtain the printed part. The laser scanned along the contour ring of the cross-section, layer by layer from the outside inwards towards the center. The printing parameters were: layer thickness 0.04mm, scanning speed 1000mm / s, scanning spacing 0.08mm, and laser power 350W.

[0109] Step 3: Post-processing

[0110] The printed parts were annealed, with the annealing process involving holding at 780℃ for 1 hour followed by furnace cooling. After annealing, the outer spiral structure of the sample was polished with an electric grinder to remove the printing excess to the product dimensions. Finally, sandblasting was performed to obtain the antenna product.

[0111] The resulting titanium alloy four-arm helical antenna had numerous burrs after production, which easily caused defects in the helical structure during polishing, making it difficult to control the dimensions of the helical structure. Fluorescent penetrant testing revealed gaps and other defects exceeding standard specifications, indicating that existing 3D printing processes are insufficient to achieve high-quality forming of this high aspect ratio titanium alloy product.

Claims

1. A 3D printing method for a high aspect ratio titanium alloy four-arm helical satellite antenna, characterized in that: The material of the high aspect ratio titanium alloy quad-helical satellite antenna is TC4 alloy, with an aspect ratio greater than or equal to 6. The quad-helical structure is an inner and outer helix structure with an arm thickness of 1.5~2.5mm. The angle between the inner and outer helix structure and the horizontal plane is 50° or less. In the quad-helical structure, there are hollows between adjacent helices and between the helix and the central axis. The 3D printing method includes the following steps: Step 1: Preheating The TC4 powder raw material and the substrate are preheated separately, wherein the powder preheating temperature is A and the substrate preheating temperature is B; wherein A is 200~550℃ and B is 300~600℃, and B is greater than A. Step 2: Print the remaining amount Set the printing allowance, and use the contour spiral scanning strategy for SLM printing to obtain the printed part; The setting of the printing allowance is based on the product structure to set the printing allowance of the outer spiral structure, where the wall thickness of the outer spiral structure of the product is X, the designed printing wall thickness is Y, and the printing allowance Z=YX, satisfying Z / X<20%; In step two, the SLM printing process uses the following parameters: layer thickness 0.02~0.06mm, scanning speed 800~1800mm / s, scanning spacing 0.04~0.1mm, and laser power 250~500W. Step 3: Post-processing The printed parts are annealed, and the annealed samples are then polished and sandblasted to obtain high-quality antenna products.

2. The 3D printing method for a high aspect ratio titanium alloy four-arm helical satellite antenna according to claim 1, characterized in that: In step one, A is 400~550℃ and B is 500~600℃.

3. The 3D printing method for a high aspect ratio titanium alloy four-arm helical satellite antenna according to claim 1, characterized in that: The spiral has a height-to-diameter ratio greater than or equal to 6, a diameter less than or equal to 40 mm, and a height greater than or equal to 90 mm.

4. The 3D printing method for a high aspect ratio titanium alloy four-arm spiral satellite antenna according to claim 1, characterized in that: The angle between the inner spiral structure and the horizontal plane is 45°~50°, and the angle between the outer spiral structure and the horizontal plane is 35°~45°.

5. The 3D printing method for a high aspect ratio titanium alloy four-arm spiral satellite antenna according to claim 1, characterized in that: In step one, the powder raw material is TC4 powder prepared by gas atomization process, and the powder particle size is 15-53μm.

6. The 3D printing method for a high aspect ratio titanium alloy four-arm helical satellite antenna according to claim 1, characterized in that: In step one, the preheating process involves first placing the powder material in a drying oven and heating it to temperature A, then loading it into the powder hopper of the SLM printing equipment, evacuating it, and introducing inert gas. Subsequently, the substrate is heated to temperature B using the equipment's built-in heating device, where A = BC and C is 30~100℃.

7. The 3D printing method for a high aspect ratio titanium alloy four-arm spiral satellite antenna according to claim 1, characterized in that: In step two, the contour spiral scanning strategy involves the laser scanning and shaping the contour ring of the cross-section layer by layer from the outside to the center.

8. The 3D printing method for a high aspect ratio titanium alloy four-arm helical satellite antenna according to claim 1, characterized in that: In step two, the SLM printing process is carried out with the following printing parameters: layer thickness 0.03~0.05mm, scanning speed 1200~1800mm / s, scanning spacing 0.06~0.1mm, and laser power 320~400W.

9. The 3D printing method for a high aspect ratio titanium alloy four-arm spiral satellite antenna according to claim 1, characterized in that: In step three, the annealing process involves holding the furnace at 700-850℃ for 0.5-2 hours and then cooling it in the furnace.

10. The 3D printing method for a high aspect ratio titanium alloy four-arm helical satellite antenna according to claim 1, characterized in that: The resulting high aspect ratio titanium alloy quad-arm spiral satellite antenna is suitable for use as a communication antenna for high-precision satellite navigation.

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