A solid propellant grain with complex configuration and a rapid forming method thereof

Abstract

The present application relates to the technical field of composite solid propellant forming process, and specifically discloses a rapid forming method of complex configuration solid propellant grain, step one: configuring first slurry and second slurry for standby; step two: performing light curing printing on the first slurry, and performing light curing again to form a grain shell; step three: filling the second slurry into the grain shell to obtain a preformed solid propellant grain, and performing post-processing on the preformed solid propellant grain to obtain a complex configuration solid propellant grain. The present application combines the advantages of solid propellant additive manufacturing and traditional casting forming process, and proposes a solid propellant additive manufacturing method which can ensure forming precision and improve production efficiency. The present application overcomes the defects of high porosity and slow speed of the current direct writing type additive manufacturing propellant grain, and solves the conflict problem between high precision and high efficiency existing in additive manufacturing.

Description

Technical Field

[0001] This invention relates to the field of composite solid propellant molding technology, specifically to a complex solid propellant grain and its rapid molding method. Background Technology

[0002] Traditional solid propellant manufacturing employs a casting process, which requires mold preparation, demolding, and shaping for complex propellant grains, resulting in complex operations and significant safety hazards. In recent years, additive manufacturing technology has been applied to solid propellant molding due to its advantages such as moldlessness, high molding precision, and good product adaptability. However, research has revealed that while additive manufacturing has significant advantages in producing micro-propellant grains and complex-shaped grains, for large-sized grains (e.g., larger than Φ75mm), the molding time increases dramatically, far exceeding the time required for casting. Increasing the nozzle diameter and extrusion rate can lead to a decrease in propellant molding precision, resulting in a trade-off between precision and speed. Summary of the Invention

[0003] To address the aforementioned problems, one objective of this invention is to provide a rapid prototyping method for complex solid propellant grains. Combining the advantages of solid propellant additive manufacturing and traditional casting processes, a solid propellant additive manufacturing method is proposed that ensures both molding accuracy and improved production efficiency. The method utilizes high-precision photopolymerization technology to print the outer contour of the complex propellant grain structure, and finally fills the internal areas using a traditional vacuum casting method. These two technologies work together to complete the propellant grain molding process. This overcomes the shortcomings of current direct-write additive manufacturing of propellant grains, such as high porosity and slow speed, and resolves the conflict between high precision and high efficiency in additive manufacturing.

[0004] The second objective of this invention is to provide a complex-configuration solid propellant grain with high precision.

[0005] The first technical solution adopted in this invention is: a rapid prototyping method for complex-configuration solid propellant grains, comprising:

[0006] Step 1: Prepare the first and second slurries for later use;

[0007] Step 2: The first slurry is photocured and printed, and then photocured again to form the outer shell of the propellant column;

[0008] Step 3: Fill the second slurry into the outer shell of the propellant grain to obtain a pre-formed solid propellant grain. Perform post-processing on the pre-formed solid propellant grain to obtain a complex-configuration solid propellant grain.

[0009] The components and mass fractions of the first slurry are as follows:

[0010] 20-30% photosensitive resin;

[0011] Main adhesive 10-20%;

[0012] Oxidizing agent 30-45%;

[0013] Metal fuels: 10-20%;

[0014] Other functional additives: 12-15%;

[0015] The components and mass fractions of the second slurry are as follows:

[0016] Main adhesive 10-20%;

[0017] Oxidizing agent 50-60%;

[0018] Metal fuels: 11-20%;

[0019] Other functional additives: 12-15%.

[0020] Preferably, the photosensitive resin includes a prepolymer, a diluent, and a photoinitiator.

[0021] Preferably, the prepolymer is one or more of epoxy acrylate, unsaturated resin polyester acrylate, polyurethane acrylate, acrylic resin and polyether acrylate;

[0022] The diluent is one or more of styrene, N-ethylpyrrolidone, tripropylene glycol diacrylate, and hydroxybutyl vinyl ether;

[0023] The photoinitiator is one or more of α-hydroxy ketone derivatives, benzophenone derivatives, acylphosphine oxides, anthraquinone derivatives, and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide.

[0024] Preferably, the main adhesive is one or more of the following: hydroxyl-terminated polybutadiene, polyethylene glycol, poly(3-azidomethyl-3-methylepoxybutane) polymer, poly(3,3-bis(azidomethyl)epoxybutane), polyglycidyl nitrate, 3,3-bis(azidomethyl)epoxybutane-tetrahydrofuran copolymer, polynitromethylepoxybutane, and polyglycidyl azidoglycerol ether.

[0025] The oxidant is one or more of ammonium perchlorate, ammonium nitrate, potassium perchlorate, hydrazine diperchlorate, nitrohydrazine, octogen, RDX, hexanitrohexaazaisopentane, and dinitramide ammonium;

[0026] The metal fuel is one or more of aluminum powder, magnesium powder, boron powder, beryllium powder, magnesium-aluminum alloy powder, and aluminum trihydride;

[0027] The other functional additives include one or more of curing agents, burn rate regulators, and plasticizers.

[0028] Preferably, the curing agent is one or more of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, and polyfunctional isocyanates.

[0029] The combustion rate regulator is one or two of the following: ferric oxide, copper oxide, chromium oxide, copper chromite, ferrocene and its derivatives, calcium carbonate, barium carbonate, lithium fluoride, calcium fluoride and ammonium oxalate.

[0030] The plasticizer is one or more of diisooctyl sebacate, nitrates, dioctyl adipate, and dioctyl phthalate.

[0031] Preferably, the photopolymerization printing in step two includes the use of stereolithography, digital light processing, or continuous liquid surface manufacturing technology.

[0032] The selected method is to use ultraviolet light for curing during the second step of the light curing process.

[0033] Preferably, the method for filling the second slurry into the outer shell of the propellant column in step three includes vacuum casting, tube casting, or pressurized casting.

[0034] Preferably, the post-treatment of the pre-formed solid propellant column in step three involves placing it in a constant temperature oven at 50°C for 5-7 days.

[0035] The second technical solution adopted in this invention is: a complex-configuration solid propellant grain prepared by a rapid prototyping method, comprising an inner propellant layer and a high-precision grain shell containing photosensitive resin.

[0036] The beneficial effects of the above technical solution are as follows:

[0037] Compared with existing technologies, the method provided by this invention combines the advantages of solid propellant additive manufacturing and traditional casting molding processes. The contour printing uses photopolymerization technology, resulting in high molding accuracy and fast printing speed. The internal structure is filled densely using traditional casting methods, resulting in good mechanical properties and high strength. The method provided by this invention eliminates the most dangerous steps in traditional processes, such as demolding and shaping, greatly improving the safety factor of propellant production. The method provided by this invention can realize in-situ molding of irregularly shaped propellant and layered propellant, achieving flexible, demand-specific, and automated manufacturing of propellant. Attached Figure Description

[0038] Figure 1 A process flow diagram of a rapid prototyping method for complex-configuration solid propellant grains provided as an embodiment of the present invention;

[0039] Figure 2A top view of a complex-configuration solid propellant grain provided in one embodiment of the present invention;

[0040] Figure 3 A schematic diagram of a complex solid propellant grain provided in one embodiment of the present invention;

[0041] Wherein, 1-the outer shell of the propellant grain, 2-the inner propellant layer. Detailed Implementation

[0042] The embodiments of this application will be described in further detail below. Obviously, the described embodiments are only a part of the embodiments of this application, and not an exhaustive list of all embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other.

[0043] The terms “first,” “second,” etc. (if applicable) in the specification and claims are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data used in this way can be interchanged where appropriate so that the embodiments described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion, such as a process, method, system, product, or apparatus that comprises a series of steps or units, not necessarily limited to those explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0044] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0045] Example 1

[0046] One embodiment of the present invention provides a solid propellant grain, such as Figure 2 and Figure 3 As shown, it includes an inner propellant layer 2 and a high-precision propellant grain shell 1 containing photosensitive resin.

[0047] Hydroxyl-terminated polybutadiene is used as the main binder. The photosensitive resin is selected from epoxy acrylate, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), and N-ethylpyrrolidone. The oxidant is ammonium perchlorate, the metal fuel is nano-aluminum powder, the curing agent is toluene diisocyanate (TDI), and the functional additives are diethylamine, ferric oxide, and N,N'-diphenyl-p-phenylenediamine. The detailed component contents are shown in Table 1 below.

[0048] Table 1 Formulation of Complex Solid Propellant Columns

[0049]

[0050] Prepared using a rapid prototyping method for solid propellant grains with complex configurations. Figure 1 A process flow diagram of a rapid prototyping method for complex-configuration solid propellant grains provided in an embodiment of the present invention.

[0051] First, the light-curing slurry a is mixed evenly using an acoustic resonance device according to the set ratio. Then, it is transferred to the material tank of the SLA device, and the airfoil propellant column outline slice model is imported. The ultraviolet light device moves quickly along the set path, and the forming platform gradually moves down to complete the propellant column outline and forming. After printing, the model is removed from the platform and placed in a constant temperature chamber with an ultraviolet lamp for post-curing.

[0052] Traditional slurry b was mixed in a vertical kneader according to a set ratio; the outline of the drug column was transferred to a vacuum casting transposition, and the traditional slurry was poured into the interlayer under vacuum until the liquid level was flush with the edge of the drug column. Finally, it was placed in a constant temperature oven at 50°C for 5 days.

[0053] This example shortens the molding process of a complex wheel-shaped propellant cone with a diameter of 12cm and a height of 20cm from 8 hours to 3 hours. The manufactured propellant cone has a smooth surface, and the actual manufactured propellant cone size deviates from the design size by less than 0.1%, significantly improving molding accuracy.

[0054] Example 2

[0055] The detailed component contents are shown in Table 2 below.

[0056] Table 2 Formulation of Complex Solid Propellant Columns (Part 2)

[0057]

[0058] First, the light-curing slurry a is mixed evenly using an acoustic resonance device according to the set ratio. Then, it is transferred to the material tank of the SLA device, and the airfoil propellant column outline slice model is imported. The ultraviolet light device moves quickly along the set path, and the forming platform gradually moves down to complete the propellant column outline and forming. After printing, the model is removed from the platform and placed in a constant temperature chamber with an ultraviolet lamp for post-curing.

[0059] Traditional slurry b was mixed in a vertical kneader according to a set ratio; the outline of the drug column was transferred to a vacuum casting transposition, and the traditional slurry was poured into the interlayer under vacuum until the liquid level was flush with the edge of the drug column. Finally, it was placed in a constant temperature oven at 50°C for 7 days.

[0060] This example shortens the molding process of a complex wheel-shaped propellant cone with a diameter of 12cm and a height of 20cm from 8 hours to 3 hours. The manufactured propellant cone has a smooth surface, and the actual manufactured propellant cone size deviates from the design size by less than 0.1%, significantly improving molding accuracy.

[0061] Example 3

[0062] The detailed component contents are shown in Table 3 below.

[0063] Table 3. Formulation of Complex Solid Propellant Columns (Part 3)

[0064]

[0065] Example 4

[0066] The detailed component contents are shown in Table 4 below.

[0067] Table 4. Formulation of Complex Solid Propellant Columns (Part 4)

[0068]

[0069]

[0070] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A rapid prototyping method for solid propellant grains with complex configurations, characterized in that, include: Step 1: Prepare the first and second slurries for later use; Step 2: The first slurry is photocured and printed, and then photocured again to form the outer shell of the propellant column; Step 3: Fill the second slurry into the outer shell of the propellant grain to obtain a pre-formed solid propellant grain. Perform post-processing on the pre-formed solid propellant grain to obtain a complex-configuration solid propellant grain. The components and mass fractions of the first slurry are as follows: Photosensitive resin 20-30%; Main adhesive 10-20%; Oxidizing agent 30-45%; Metal fuels: 10-20%; Other functional additives: 12-15%; The components and mass fractions of the second slurry are as follows: Main adhesive 10-20%; Oxidizing agent 50-60%; Metal fuels: 11-20%; Other functional additives: 12-15%.

2. The rapid prototyping method for complex-configuration solid propellant grains according to claim 1, characterized in that, The photosensitive resin includes a prepolymer, a diluent, and a photoinitiator.

3. The rapid prototyping method for complex-configuration solid propellant grains according to claim 2, wherein the prepolymer is one or more of epoxy acrylate, unsaturated resin polyester acrylate, polyurethane acrylate, acrylic resin and polyether acrylate; The diluent is one or more of styrene, N-ethylpyrrolidone, tripropylene glycol diacrylate, and hydroxybutyl vinyl ether; The photoinitiator is one or more of α-hydroxy ketone derivatives, benzophenone derivatives, acylphosphine oxides, anthraquinone derivatives, and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide.

4. The rapid prototyping method for complex-configuration solid propellant grains according to claim 1, characterized in that, The main adhesive is one or more of the following: hydroxyl-terminated polybutadiene, polyethylene glycol, poly(3-azidomethyl-3-methylepoxybutane) polymer, poly(3,3-bis(azidomethyl)epoxybutane), polyglycidyl nitrate, 3,3-bis(azidomethyl)epoxybutane-tetrahydrofuran copolymer, polynitromethylepoxybutane, and polyglycidyl azidoglycerol ether. The oxidant is one or more of the following: ammonium perchlorate, ammonium nitrate, potassium perchlorate, hydrazine diperchlorate, nitrohydrazine, octogen, rhesin, hexanitrohexaazaisowulzane, and dinitramide ammonium. The metal fuel is one or more of aluminum powder, magnesium powder, boron powder, beryllium powder, magnesium-aluminum alloy powder, and aluminum trihydride; The other functional additives include one or more of curing agents, burn rate regulators, and plasticizers.

5. The rapid prototyping method for complex-configuration solid propellant grains according to claim 4, characterized in that, The curing agent is one or more of diphenylmethane diisocyanate, toluene diisocyanate, and isophorone diisocyanate; The combustion rate regulator is one or two of the following: ferric oxide, copper oxide, chromium oxide, copper chromite, ferrocene and its derivatives, calcium carbonate, barium carbonate, lithium fluoride, calcium fluoride and ammonium oxalate. The plasticizer is one or more of diisooctyl sebacate, nitrates, dioctyl adipate, and dioctyl phthalate.

6. The rapid prototyping method for complex-configuration solid propellant grains according to claim 1, characterized in that, The photopolymerization printing described in step two includes the use of stereolithography, digital light processing, or continuous liquid surface manufacturing technology.

7. The rapid prototyping method for complex-configuration solid propellant grains according to claim 1, characterized in that, The second light curing mentioned in step two refers to curing using ultraviolet light.

8. The rapid prototyping method for complex-configuration solid propellant grains according to claim 1, characterized in that, The method for filling the second slurry into the outer shell of the drug column in step three includes vacuum casting, tube casting, or pressure casting.

9. The rapid prototyping method for complex-configuration solid propellant grains according to claim 1, characterized in that, In step three, the pre-formed solid propellant grains are post-treated by being placed in a constant temperature oven at 50°C for 5-7 days.

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