A method for installing a thin-film heater suitable for spacecraft storage and supply curved surface structures.

Abstract

This invention discloses a method for installing a thin-film heater suitable for curved surfaces in spacecraft storage and supply systems. The method involves determining the optimal installation area and avoiding stress concentration zones through surface pretreatment, using silicone rubber for filling and leveling, and constructing edge stress buffers. After applying adhesive to both sides of the bonding surface, pre-positioning and conformal rolling are used to eliminate air bubbles. Multi-level pressure control (1.5-2 N / cm²) is implemented using foam, central radial adhesive tape, and Kevlar fiber tension-adjustable straps. Finally, curing is completed through a gradient temperature curing process (initial curing at 25℃ → enhanced curing at 60℃ → stress release through stepped cooling). This innovative interface filling and multi-dimensional pressure control strategy effectively solves the problems of curved surface adaptation failure (edge ​​warping, peeling) and air gap defects (heating wire breakage) in traditional processes. Furthermore, the process is highly operable and exhibits consistent implementation results, significantly improving the thermal control reliability of spacecraft storage and supply systems, ensuring the maintenance of supercritical krypton and the performance of spacecraft on-orbit missions.

Description

Technical Field

[0001] This application relates to the field of aerospace technology, and in particular to a method for installing a thin-film heater suitable for the curved surface structure of a spacecraft's storage and supply system. Background Technology

[0002] In the fields of deep space exploration and satellite orbit maintenance in aerospace engineering, krypton is the core propellant for electric propulsion systems (such as ion thrusters and Hall effect thrusters), and the reliability of its storage and supply system directly determines the on-orbit lifespan and mission performance of the spacecraft. In existing technologies, aerospace storage and supply systems typically employ lightweight composite gas cylinder structures made of a metal liner and a carbon fiber wound shell to meet the spacecraft's requirements for lightweight equipment and structural strength.

[0003] To ensure the adaptability of the aforementioned composite gas cylinders to the extreme environments in space (such as extremely low temperatures and drastic temperature fluctuations), a thin-film heater needs to be installed on their surface. This thin-film heater achieves its heating function by converting electrical energy into heat energy, and is further encased in multi-layer thermal insulation material (MLI) to maintain the stability of the internal temperature of the gas cylinder (temperature change rate ΔT < 5℃ / h), thereby ensuring that the krypton gas is always in a supercritical state (its critical temperature is -63.8℃).

[0004] Currently, thin-film heaters are typically fixed to the surface of stand-alone equipment using GD414 silicone rubber adhesive. For conventional planar stand-alone equipment, after the heater is installed, it can be fixed by applying continuous pressure with sandbags or small steel balls. The pressure device is removed after the silicone rubber has fully cured (usually about 24 hours), and this process ensures the reliability of planar bonding. However, on the curved structure of the storage and supply system, due to the limitations of its surface geometry, it is impossible to apply continuous and uniform pressure to the thin-film heater. This lack of pressure application directly leads to a decrease in bonding quality, specifically: air bubbles and voids are easily generated during the curing process; the constantan heating wire inside the heater is prone to breakage after thermal vacuum cycling tests; and under vibration, the heater edges are prone to warping and localized peeling, ultimately leading to the failure of thermal control implementation.

[0005] Therefore, how to effectively solve the problem of reliable bonding of thin-film heaters on curved structures has become a key technical challenge that needs to be addressed by those skilled in the art. Summary of the Invention

[0006] Edge warping is prone to occur during the process, and localized peeling occurs after vibration environmental testing. Uncontrollable bubbles and voids are generated during the curing process. After thermal vacuum cycling test, the constantan heating wire inside the heater breaks, and the fracture morphology analysis shows brittle fracture characteristics.

[0007] To address the above problems, this invention provides a method for installing a thin-film heater suitable for the curved surface structure of a spacecraft's storage and supply system, comprising:

[0008] Determine the deployment area and pre-treat the surface of the deployment area;

[0009] Silicone rubber is applied to the bonding surfaces of the storage and supply unit and the film heater, and the four right-angled sides of the film heater are pre-positioned and temporarily fixed with tape.

[0010] Cover the surface of the thin-film heater with an isolation film, and use a scraper to roll it evenly from the center line of the heater to both sides to make the heater conformally fit the entire area of ​​the curved substrate and eliminate air bubbles.

[0011] Foam is laid on the surface of the isolation membrane and fixed with a central radial tape method to achieve uniform distribution of local pressure;

[0012] Using straps to implement circumferential restraint and maintain continuous pressure; and

[0013] Silicone rubber is cured by gradient temperature control.

[0014] In one embodiment of the present invention, determining the deployment area and pre-treating the surface of the deployment area includes:

[0015] Pre-layout tests were conducted to determine the optimal placement area of ​​the heaters on the curved substrate of the storage and supply unit, thus avoiding areas of structural stress concentration.

[0016] Silicone rubber is used to fill the surface of selected areas to eliminate surface defects;

[0017] Extend the filler layer outward from the selected area to cover a 1cm range of the substrate surface, forming an edge stress buffer zone;

[0018] Curing of the filler layer.

[0019] In one embodiment of the present invention, the curing of silicone rubber by gradient temperature control includes:

[0020] Curing is carried out at a constant pressure of 25°C for 4 hours at room temperature;

[0021] The components were placed in a high and low temperature chamber and heated in stages to 60°C at a rate of 5°C per hour, and cured at this temperature for 8 hours.

[0022] After the reinforced and cured components are naturally cooled to room temperature inside the high and low temperature chamber, they are taken out and kept at room temperature (25°C) for 12 hours to cure.

[0023] Remove the straps from the storage and supply unit and allow it to cure at room temperature (25°C) for 24 hours.

[0024] In one embodiment of the present invention, it further includes:

[0025] Check whether the thin-film heater exhibits edge warping.

[0026] Check for air bubbles and voids at the bonding area between the storage and supply unit and the thin-film heater;

[0027] If the test result is negative, the implementation effect is deemed satisfactory, and the installation of the thin-film heater is completed.

[0028] If the test result is positive, the implementation effect is deemed unqualified, and the thin-film heater is removed and reinstalled.

[0029] The present invention also provides a thin-film heater suitable for spacecraft storage and supply curved surface structures, comprising:

[0030] The storage and supply unit is configured as the mounting base for the heater;

[0031] Thin-film heaters are flexible, thin-film structures designed to conformally fit curved substrates.

[0032] The separator, covering the surface of the thin-film heater, is made of chemically inert PTFE material;

[0033] Foam, applied to the surface of the insulating membrane, is configured to evenly distribute external pressure throughout the heater area;

[0034] The straps are configured to apply circumferential constraints, providing continuous pressure.

[0035] Silicone rubber is configured to fill surface defects of the storage and supply unit, construct edge buffer zones, and fix the thin-film heater to the storage and supply unit;

[0036] The tape is configured to pre-position the thin-film heater and apply central radial spiral pressure to help disperse local pressure.

[0037] In one embodiment of the present invention, the silicone rubber is GD414 silicone rubber.

[0038] In one embodiment of the present invention, the tape is a high-temperature resistant polyimide pressure-sensitive tape.

[0039] In one embodiment of the present invention, the foam is antistatic EVA foam with a side length greater than 5cm of the thin film heater and a thickness of 5mm.

[0040] In one embodiment of the present invention, the strap is made of Kevlar fiber and has adjustable tension, used to provide a continuous pressure of 1.5-2 N / cm².

[0041] The present invention has the following beneficial effects:

[0042] (1) The air gap elimination effect is significant. The ambient temperature stepped curing process (gradient temperature curing) is adopted, and the rolling and venting operation can effectively avoid the generation of air bubbles and voids during the curing process, achieving a residual air bubble rate of <0.1% in the adhesive layer. This solves the problem of reduced heat conduction efficiency and broken heating wire caused by air bubbles in traditional curved surface bonding (such as the brittle fracture of constantan heating wire after thermal vacuum cycling).

[0043] (2) Precise stress balance control: Through a three-level pressure system (antistatic EVA foam pressure dispersion, central radial tape spiral pressure, and Kevlar strap circumferential constraint) combined with edge stress buffer design, the interface shear stress gradient is strictly controlled, which significantly reduces the risk of heater edge warping and local peeling under vibration environment, and improves surface adaptability and structural stability.

[0044] (3) This method is specifically designed for the curved structure of the spacecraft storage and supply system, breaking through the bottleneck of traditional planar bonding process in curved applications, significantly improving the long-term reliability of thin film heaters in extreme environments (such as high and low temperatures, vibration, and vacuum in deep space exploration), and indirectly ensuring the on-orbit life and mission effectiveness of the spacecraft. Attached Figure Description

[0045] Figure 1 A flowchart illustrating the installation process of a thin-film heater suitable for a spacecraft storage and supply curved surface structure, according to an embodiment of the present invention, is shown; and

[0046] Figure 2 A schematic diagram of the exploded structure of a thin-film heater suitable for a spacecraft storage and supply curved surface structure is shown in one embodiment of the present invention. Detailed Implementation

[0047] In the following description, the invention is described with reference to various embodiments. However, those skilled in the art will recognize that the embodiments may be practiced without one or more specific details or with other alternatives and / or additional methods, materials, or components. In other instances, well-known structures, materials, or operations are not shown or described in detail so as not to obscure the inventive points of the invention. Similarly, for illustrative purposes, specific quantities, materials, and configurations are set forth to provide a comprehensive understanding of embodiments of the invention. However, the invention is not limited to these specific details.

[0048] In this invention, the various embodiments are merely intended to illustrate the solutions of the invention and should not be construed as limiting.

[0049] In this specification, references to "an embodiment" or "this embodiment" mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of the invention. The phrase "in one embodiment" appearing throughout this specification does not necessarily refer to the same embodiment in all instances.

[0050] Furthermore, the numbering of the steps in the methods of the present invention does not limit the execution order of the method steps. Unless otherwise specified, the method steps may be executed in different orders.

[0051] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0052] Figure 1 A flowchart illustrating the installation process of a thin-film heater suitable for a spacecraft storage and supply curved surface structure is shown in one embodiment of the present invention.

[0053] like Figure 1 As shown, in one embodiment of the present invention, the installation process of the thin-film heater includes:

[0054] Before implementing S100, prepare the following items for this embodiment: storage and supply unit, thin film heater, isolation membrane, foam, straps, and tools such as GD414 silicone rubber, high-temperature resistant polyimide pressure-sensitive tape, and scraper, and place them on an anti-static workbench.

[0055] S200 determines the implementation location and determines the optimal heater layout area on the curved substrate of the storage and supply unit through pre-layout tests, avoiding areas of structural stress concentration.

[0056] The S300 storage and supply surface is leveled by using GD414 silicone rubber to fill and level the carbon fiber composite material surface of the selected area of ​​the storage and supply unit, thereby eliminating pits on the surface of the storage and supply unit.

[0057] S400 constructs a stress buffer zone with edge reinforcement treatment. The filler layer extends outward from the selected area in S200, covering a 1cm range of the substrate surface, thus constructing an edge stress buffer zone. The GD414 silicone rubber on the filler layer is fully cured. In this embodiment, the curing conditions are 25℃ / 50%RH, and the curing time is 24h.

[0058] S500 coated silicone rubber: Apply approximately 0.3mm thick GD414 silicone rubber evenly to the bonding surface between the storage unit and the thin-film heater to ensure no missed coating on the thin-film heater coating surface.

[0059] For the S600 heater pre-positioning, the four right-angled sides of the thin-film heater are pre-positioned and then attached using high-temperature resistant polyimide pressure-sensitive tape.

[0060] The S700 is used to apply a release liner, covering the other side of the thin-film heater with a chemically inert PTFE release liner. A scraper is then used to evenly roll and press the liner from the center line of the heater outwards to both sides, ensuring conformal adhesion between the heater and the entire curved substrate, and eliminating air bubbles.

[0061] For S800 foam installation, a piece of antistatic EVA foam with a side length greater than 5cm and a thickness of 5mm (larger than the film heater) is laid onto the isolation membrane to evenly distribute local pressure. A center-radial tape fixing method is used, applying pressure spirally from the center of the antistatic EVA foam towards the edge using high-temperature resistant polyimide pressure-sensitive tape (tape overlap ≥50%).

[0062] S900 straps are used for fixation, and Kevlar fiber tension-adjustable straps are used to implement circumferential restraint, maintaining a continuous pressure of 1.5-2 N / cm².

[0063] S1000 stepped temperature curing, implementing the stepped temperature curing method for GD414:

[0064] Initial curing: Curing at constant pressure for 4 hours at room temperature (25℃);

[0065] Enhanced curing: Place the implemented components in a high and low temperature chamber, gradually increase the temperature to 60°C (heating rate of 5°C per hour), and cure at this temperature for 8 hours;

[0066] Level 1 stress release: After the reinforced and cured components are naturally cooled to room temperature inside the high and low temperature chamber, they are taken out and kept at room temperature (25°C) for 12 hours to cure.

[0067] Secondary stress release: After primary stress release, remove the Kevlar fiber tension adjustable straps on the storage and supply unit and allow it to cure at room temperature (25°C) for 24 hours.

[0068] S1100 checks whether the implementation effect is qualified and tests whether the thin-film heater meets the implementation effect.

[0069] In one specific embodiment, the detection method can be: checking whether the thin-film heater has edge warping, and checking whether there are air bubbles and voids at the bonding part between the storage and supply unit and the thin-film heater.

[0070] If the test result is negative, the implementation effect is deemed satisfactory, and the implementation of the thin-film heater is completed.

[0071] If the test result is positive, the implementation effect is deemed unqualified. The thin-film heater will then be removed and the process will return to S500 for reinstallation.

[0072] It should be noted that at least one or all of the above steps can be performed by an industrial robot. The industrial robots include, but are not limited to: articulated robots, SCARA robots, Cartesian robots, Delta robots, collaborative robots (Cobots), and industrial mobile robots (IMRs).

[0073] Industrial robots can be composed of a mechanical body, a drive system, a control system, and a sensing system. The mechanical body is the foundation for performing tasks; for example, the multi-segment arms and rotary joints of an articulated robot, and the linear guides of a Cartesian robot, provide physical support for movement. The drive system provides power to the mechanical components through motors, hydraulic or pneumatic devices, ensuring precise speed and force output. The control system receives instructions and plans the motion path, ensuring the coordination and accuracy of the movements. The sensing system, with the help of sensors, vision devices, etc., enables the robot to identify workpieces, detect the environment, and achieve precise positioning or obstacle avoidance.

[0074] These structures work together to enable robots to efficiently complete various tasks in manufacturing. The flexible structure of the mechanical body allows the robot to perform operations such as coating, surface treatment, welding, assembly, and positioning / pre-positioning; the stable power output of the drive system ensures the force and precision of the operation; the control system ensures that the robot operates efficiently according to preset programs, improving production consistency; and the perception system enhances the robot's adaptability, such as achieving precise grasping of parts through visual recognition, or sensing the position of people in collaborative scenarios to ensure safety. The use of industrial robots can meet the manufacturing industry's demand for efficient, precise, and stable operations, thereby improving the production efficiency and quality of this invention.

[0075] Figure 2 A schematic diagram of the exploded structure of a thin-film heater suitable for a spacecraft storage and supply curved surface structure is shown in one embodiment of the present invention.

[0076] like Figure 2 As shown, in one embodiment of the present invention, a thin-film heater suitable for a spacecraft storage and supply curved surface structure includes:

[0077] The storage and supply unit 1, the mounting base of the heater, is a curved structure composed of a metal inner liner and a carbon fiber wound shell (such as a spacecraft composite gas cylinder), which is the carrier of the heater's heating object.

[0078] Thin-film heater 2, with a core heating element, has a built-in constantan heating wire (which converts electrical energy into heat energy when current passes through it). The whole is a thin-film flexible structure that can adapt to conformal bonding with curved substrates.

[0079] The isolation membrane 3, made of chemically inert PTFE material, covers the surface of the heater to prevent the heater from being damaged by direct contact with subsequent components, while also facilitating the rolling and venting of air.

[0080] Antistatic EVA foam 4, with a side length 5cm longer than the heater and a thickness of 5mm, is laid on the surface of the isolation membrane 3. It can evenly distribute external pressure to the entire area of ​​the heater and is suitable for curved surfaces.

[0081] Kevlar fiber tension adjustable strap 5 is used to implement circumferential restraint, providing a continuous pressure of 1.5-2 N / cm² to ensure that the heater and the substrate are in close contact during the curing process.

[0082] GD414 silicone rubber, as the core adhesive, is used to fill defects on the substrate surface, build edge buffer zones, and fix the heater to the substrate. It has good resistance to high and low temperatures and good adhesive strength.

[0083] High-temperature resistant polyimide pressure-sensitive tape is used for heater pre-positioning (temporary fixation) and central radial spiral pressure application to help disperse local pressure.

[0084] In one embodiment of the present invention, the bubble residual rate of the adhesive layer of the thin-film heater suitable for the curved surface structure of spacecraft storage is <0.1%, the interfacial shear stress gradient is ≤±8%, and the thermal conductivity is ≥1.2W / (m·K).

[0085] Although various embodiments of the invention have been described above, it should be understood that they are presented by way of example only and not as limitations. It will be apparent to those skilled in the art that various combinations, modifications, and alterations can be made without departing from the spirit and scope of the invention. Therefore, the breadth and scope of the invention disclosed herein should not be limited by the exemplary embodiments disclosed above, but should be defined solely by the appended claims and their equivalents.

Claims

1. A method for installing a thin-film heater suitable for the curved surface structure of a spacecraft's storage and supply system, characterized in that, include: Determine the deployment area and pre-treat the surface of the deployment area; Silicone rubber is applied to the bonding surfaces of the storage and supply unit and the film heater, and the four right-angled sides of the film heater are pre-positioned and temporarily fixed with tape. Cover the surface of the thin-film heater with an isolation film, and use a scraper to roll it evenly from the center line of the heater to both sides to make the heater conformally fit the entire area of ​​the curved substrate and eliminate air bubbles. Foam is laid on the surface of the isolation membrane and fixed with a central radial tape method to achieve uniform distribution of local pressure; Use straps to implement circumferential restraint and maintain continuous pressure; as well as Silicone rubber is cured by gradient temperature control.

2. The method for installing a thin-film heater suitable for spacecraft storage and supply curved surface structures according to claim 1, characterized in that, Determine the deployment area and perform surface pretreatment for the deployment area, including: Pre-layout tests were conducted to determine the optimal placement area of ​​the heaters on the curved substrate of the storage and supply unit, thus avoiding areas of structural stress concentration. Silicone rubber is used to fill the surface of selected areas to eliminate surface defects; Extend the filler layer outward from the selected area to cover a 1cm range of the substrate surface, forming an edge stress buffer zone; Curing of the filler layer.

3. The method for installing a thin-film heater suitable for spacecraft storage and supply curved surface structures according to claim 1, characterized in that, Curing silicone rubber through gradient temperature control includes: Curing is carried out at a constant pressure of 25°C for 4 hours at room temperature; The components were placed in a high and low temperature chamber and heated in stages to 60°C at a rate of 5°C per hour, and cured at this temperature for 8 hours. After the reinforced and cured components are naturally cooled to room temperature inside the high and low temperature chamber, they are taken out and kept at room temperature (25°C) for 12 hours to cure. Remove the straps from the storage and supply unit and allow it to cure at room temperature (25°C) for 24 hours.

4. The method for installing a thin-film heater suitable for spacecraft storage and supply curved surface structures according to claim 1, characterized in that, Also includes: Check whether the thin-film heater exhibits edge warping. Check for air bubbles and voids at the bonding area between the storage and supply unit and the thin-film heater; If the test result is negative, the implementation effect is deemed satisfactory, and the installation of the thin-film heater is completed. If the test result is positive, the implementation effect is deemed unqualified, and the thin-film heater is removed and reinstalled.

5. A thin-film heater suitable for the curved surface structure of spacecraft storage and supply systems, characterized in that, include: The storage and supply unit is configured as the mounting base for the heater; Thin-film heaters are flexible, thin-film structures designed to conformally fit curved substrates. The separator, covering the surface of the thin-film heater, is made of chemically inert PTFE material; Foam, applied to the surface of the insulating membrane, is configured to evenly distribute external pressure throughout the heater area; The straps are configured to apply circumferential constraints, providing continuous pressure. Silicone rubber is configured to fill surface defects of the storage and supply unit, construct edge buffer zones, and fix the thin-film heater to the storage and supply unit; The tape is configured to pre-position the thin-film heater and apply central radial spiral pressure to help disperse local pressure.

6. The thin-film heater suitable for spacecraft storage and supply curved surface structures according to claim 5, characterized in that, The silicone rubber is GD414 silicone rubber.

7. The thin-film heater suitable for spacecraft storage and supply curved surface structures according to claim 5, characterized in that, The tape is a high-temperature resistant polyimide pressure-sensitive tape.

8. The thin-film heater suitable for spacecraft storage and supply curved surface structures according to claim 5, characterized in that, The foam is antistatic EVA foam, with a side length 5cm longer than that of the film heater and a thickness of 5mm.

9. The thin-film heater suitable for spacecraft storage and supply curved surface structures according to claim 5, characterized in that, The straps are made of Kevlar fiber and have adjustable tension, providing continuous pressure of 1.5-2 N / cm².

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