High-reliability solid propellant 3D printing curing equipment

Abstract

The invention discloses high-reliability solid propellant 3D printing curing equipment. The high-reliability solid propellant 3D printing curing equipment comprises a solid propellant 3D printing nozzle structure, an ultraviolet lamp and a printing platform; the high-reliability solid propellant 3D printing nozzle structure comprises a plunger, a charging barrel, a rubber sealing gasket, a nozzle and a nozzle light shield. When solid propellant printing is carried out, the plunger extrudes solid propellant slurry in the charging barrel to be extruded out of the nozzle, the photocuring equipment irradiates the printed slurry to carry out photocuring shaping, and the light shield is installed at the joint of the nozzle, so that the solid propellant is prevented from being cured near a discharging hole of the nozzle to form blockage. The method is wide in application scene, and the solid propellant can be uniformly, efficiently and stably cured and formed.

Description

Technical Field

[0001] The present invention relates to a high-reliability solid propellant 3D printing and curing device, belonging to the field of aerospace propulsion technology. Background Art

[0002] 3D printing is a physical manufacturing technology that forms materials through layer-by-layer stacking. It offers significant advantages for manufacturing complex components and specialized structures, and is a cutting-edge manufacturing technology transforming the production of solid propellant grains. When 3D printing solid propellants, a premixed slurry is injected into a barrel and extruded through a nozzle, depositing the slurry layer by layer. Curing methods (such as light-curing and heat-assisted curing) ensure that the slurry surface solidifies immediately after extrusion, providing a certain degree of shape retention and support, thereby preventing the solid propellant slurry from collapsing.

[0003] As a key component in solid propellant 3D printing, the nozzle directly impacts printing efficiency and the performance of the printed solid propellant. A reasonable nozzle design should ensure continuous and stable slurry extrusion and good compatibility with auxiliary light-curing equipment, avoiding issues such as nozzle malfunction due to the light-curing process, poor light-curing results, and structural collapse caused by the nozzle.

[0004] Currently, solid propellant 3D printing faces numerous technical bottlenecks, such as the collapse of printed parts and easy nozzle clogging. The former is due to the incomplete and slow solidification of the solid propellant, which prevents the lower layer from providing effective support when printing the upper layer. The latter is due to UV light causing the slurry near the nozzle to solidify and clog the outlet. Clearing the blockage can easily cause irreversible damage to the nozzle, and the process safety cannot be guaranteed.

[0005] Relevant scholars have done a lot of work on solid propellant 3D printing technology and nozzle design. The patent "Anti-clogging structure for 3D printing nozzle" (CN202122127501.4) provides an axially movable nozzle and a fixed plug rod (the two are coaxial). When the nozzle is blocked, the nozzle is moved axially so that the plug rod is inserted into the nozzle, thereby clearing the nozzle blockage. The patent "3D printer nozzle with stable heating and heat dissipation" (CN202320541126.4) prevents the slurry from solidifying at the nozzle and causing blockage by loading a stable thermal environment at the nozzle, with significant results. However, during the solid propellant printing process, mechanical unblocking of the anti-clogging structure can easily lead to friction fire, and direct heating of the nozzle can easily lead to local overheating and combustion. Production safety and reliability cannot be guaranteed. During the photocuring of solid propellants, there is an urgent need for a nozzle that can avoid solidification and blockage at the nozzle. Summary of the Invention

[0006] The technical problem solved by the present invention is: to overcome the shortcomings of the existing technology and provide a high-reliability solid propellant 3D printing and curing equipment with a wide range of applications, uniform and efficient light curing, and to provide technical accumulation for 3D printing in the field of solid propellant manufacturing.

[0007] The technical solution of the present invention is: a high-reliability solid propellant 3D printing and curing device, comprising: a solid propellant 3D printing nozzle structure, an ultraviolet lamp, and a printing platform; wherein the solid propellant 3D printing nozzle structure operates on the printing platform, and the ultraviolet lamp is located outside the printing platform for curing the solid propellant slurry; specifically:

[0008] The solid propellant 3D printing nozzle structure includes: a plunger, a barrel, a rubber sealing gasket, a nozzle, and a nozzle light shield; wherein:

[0009] The plunger is inserted from the rear end of the barrel to extrude the solid propellant slurry;

[0010] The other end of the barrel is the discharge end, and the port is provided with a skirt plate;

[0011] The nozzle is a frustum structure with the discharge port located at the top of the frustum. A skirt structure that matches the skirt of the barrel is provided at the bottom of the frustum structure. A rubber sealing gasket is provided between the barrel and the skirt of the nozzle. The barrel, rubber sealing gasket and nozzle are connected and fixed by bolts.

[0012] The nozzle light shield includes a base plate, a sleeve and a flange. The sleeve fits the side wall of the nozzle cone, the base plate fits the skirt surface at the bottom of the nozzle, and the flange is close to the discharge port of the nozzle.

[0013] Preferably, the UV lamp is fixed by an adjustable bracket, and the illumination power is greater than or equal to 160W;

[0014] The included angle α between the light and the upper surface of the printing platform is 30° to 60°. Specifically, when the height of the processing component is less than 50 mm, the included angle α is 30°; when the height of the processing component is more than 120 mm, the included angle α is 60°.

[0015] Preferably, the nozzle cover is made of a dark, opaque material that does not react with ethyl acetate, is heat-resistant and does not decompose at 60±10°C, and has an elastic modulus of not less than 1000 MPa.

[0016] Preferably, the minimum thickness t of the nozzle light shield is 0.5 mm, and the nozzle discharge port diameter D is N When it is greater than 10mm, the minimum thickness t is 1 to 2mm.

[0017] Preferably, the nozzle discharge diameter D N When the diameter is less than 10mm, two UV lamps are arranged; D N When it is larger than 10mm, arrange 4 to 6 ultraviolet lamps.

[0018] Preferably, when two UV lamps are arranged, the diameter D of the large circle at the outer end of the nozzle light shield flange is H The nozzle outlet diameter D N 3 to 10 times of the original diameter; when 4 to 6 UV lamps are arranged, the light intensity increases with the number of UV lamps, so the diameter D of the large circle at the outer end of the nozzle light shield flange is increased. H D N 5 to 15 times of.

[0019] Preferably, the flange of the nozzle light shield is not parallel to the base plate of the nozzle light shield, and the angle θ of the outer side of the flange tilted toward the base plate is 0 to 15 degrees to avoid scratching the surface of the formed charge after installation.

[0020] Preferably, the total length L of the nozzle is defined as N It is the distance from the nozzle skirt surface to the plane where the discharge port is located;

[0021] Define the nozzle hood length L H The distance from the bottom plate to the plane where the flange turns;

[0022] Nozzle hood length L H Than the total length of the nozzle L N 1% to 5% shorter.

[0023] Preferably, the bottom plate of the nozzle light shield is also provided with a threaded hole for connecting with the nozzle. N When the diameter is less than 10mm, four threaded holes are symmetrically processed on the bottom plate of the nozzle shield along the circumference, and the discharge diameter D N When the diameter is greater than or equal to 10 mm, 6 threaded holes are machined symmetrically along the circumferential direction on the bottom plate of the nozzle light shield;

[0024] The threaded hole size d must not be smaller than the nozzle outlet diameter D N 10% of.

[0025] Preferably, the roughness of the inner surface of the nozzle light shield and the nozzle is less than Ra 6.3, and the surface roughness of the flange of the nozzle light shield in contact with the medicine surface is less than Ra 3.2, which is conducive to cleaning the solidified medicine slurry residue on the surface of the nozzle light shield.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] (1) The surface quality of the molded parts of the present invention is improved. During printing and molding, the ultraviolet lamp realizes rapid solidification of the slurry, so that the solid propellant in the lower layer after solidification provides effective support for the upper layer printing, avoiding the problem of structural collapse caused by slow curing speed, shallow curing degree, and uneven curing;

[0028] (2) The printing process of the present invention has good continuity and high stability. In order to solve the problem of nozzle outlet clogging during light curing, a light shield adapted to the nozzle is designed to shield the nozzle outlet from light; the light shield is of moderate size, which ensures effective light shielding while having little effect on the photocuring molding of the slurry, thus avoiding blind spots in photocuring;

[0029] (3) The present invention has low energy consumption, low cost, and is convenient for operators to observe. Existing light-curing equipment is generally fixed inside the printing frame to achieve full coverage of the printing area. It has high light power requirements and often requires more than four high-power ultraviolet lamps, which is not conducive to real-time observation by the operator. The light-curing auxiliary equipment of the present invention can adjust the irradiation angle according to demand, and the light only irradiates the part that needs to be cured and formed, reducing light waste and light pollution. The light shield has a simple structure, is easy to process, and is low in cost.

[0030] (4) The present invention has good reliability and high safety. After installing the structure, contactless processing can be achieved without using mechanical dredging or direct heating anti-blocking devices, thus avoiding spontaneous combustion of solid propellant during printing and ensuring processing safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of the nozzle structure of the present invention;

[0032] Figure 2 is a schematic diagram of a printing device of the present invention;

[0033] Figure 3 It is a partial schematic diagram of the nozzle and nozzle cover of the present invention.

[0034] Figure ID:

[0035] 1- plunger, 2- barrel, 3- rubber sealing gasket, 4- nozzle, 5- nozzle light shield, 6- UV lamp, 7- printing platform. DETAILED DESCRIPTION

[0036] In order to illustrate the technical solution and technical purpose of the present invention, the present invention is further introduced below with reference to the accompanying drawings and specific embodiments.

[0037] The technical solution for achieving the purpose of the present invention is as follows: a high-reliability solid propellant 3D printing and curing device comprises: a solid propellant 3D printing nozzle structure, an ultraviolet lamp 6 and a printing platform 7; wherein:

[0038] A high-reliability solid propellant 3D printing nozzle structure includes a plunger 1, a barrel 2, a rubber sealing gasket 3, a nozzle 4, and a nozzle light shield 5. The plunger 1 is inserted from the rear end of the barrel 2 to extrude the solid propellant slurry. The discharge end of the barrel 2 is provided with a skirt plate. The nozzle 4 is a frustum with a discharge port located at the top of the cone. The bottom of the cone is provided with a skirt plate structure that mates with the skirt plate of the barrel 2. Corresponding screw holes are provided on the skirt plates of the barrel 2 and nozzle 4. A rubber sealing gasket 3 is located between the skirt plates. The barrel 2, rubber sealing gasket 3, and nozzle 4 are connected and fixed by bolts.

[0039] The nozzle light shield 5 includes a bottom plate, a sleeve and a flange. The sleeve fits the side wall of the cone of the nozzle 4, the bottom plate fits the skirt surface at the bottom of the nozzle 4, and the flange is close to the discharge port of the nozzle 4.

[0040] The ultraviolet lamp 6 is located outside the printing platform 7 and is used to solidify the solid propellant slurry.

[0041] When printing with solid propellant, the plunger 1 squeezes the solid propellant slurry in the barrel 2 out of the nozzle 4, and the ultraviolet lamp 6 irradiates the printed slurry for light curing and shaping. The nozzle light shield 5 is mounted on the nozzle 4 to prevent the solid propellant from curing near the nozzle 4 outlet and forming a blockage. The overall structure of the printing device is as follows: Figure 2 shown.

[0042] In the structure of the present invention, the UV lamp 6 for curing the material should be arranged outside the printing platform 7 and fixed to the bottom of the printing device by an adjustable bracket. The upper surface of the printing platform is in the shape of a disk, and the maximum diameter of the disk is not higher than 400mm. Figure 2 As shown by the dotted line, the illumination angle α (the angle between the light and the upper surface of the printing platform) should be between 30 and 60°. When the height of the processed part is less than 50 mm, it should be 30°, and when it is higher than 120 mm, it should be 60°. The wavelength of the UV lamp is selected according to the formula, and the illumination power should be 160W or above.

[0043] The nozzle light shield 5 structure is a key component to prevent nozzle clogging, such as Figure 3 As shown, the nozzle cover 5 should be made of dark opaque material, and non-metallic materials such as plastic, rubber, latex, etc. can be used. The material should not react with ethyl acetate and should be heat-resistant and not decompose at 60±10℃ to prevent damage to the nozzle surface when cleaning. The elastic modulus of the material should not be less than 1000MPa.

[0044] The minimum thickness t of the nozzle hood 5 is 0.5 mm, and the diameter of the nozzle 4 discharge port is D N When the thickness is greater than 10 mm, the minimum thickness t is 1 to 2 mm, and the diameter D of the large circle at the outer end of the nozzle light shield 5 is H The discharge diameter D of nozzle 4 N 3 to 10 times of the nozzle 4 discharge diameter D NWhen the diameter is less than 10 mm, two UV lamps 6 are arranged along the circumference to solidify the material. N When the diameter is greater than 10 mm, 4 to 6 UV lamps 6 are arranged along the circumference. When the light intensity increases, the lower port diameter D should be appropriately increased. H It is 1 to 3 times the above diameter. H Can be in 5ⅹD N ~15ⅹD N Select within the range;

[0045] Define the total length L of the nozzle (4) N The distance from the nozzle (4) skirt surface to the plane where the discharge port is located; the length L of the nozzle light shield (5) is defined as H The distance from the bottom plate to the plane where the flange turns; the length of the nozzle light shield 5 is L H Than the total length L of nozzle 4 N 1% to 5% shorter; the flange is an upward-curved disc structure, and the angle θ of the outer side of the flange toward the base plate is 0 to 15° to avoid scratching the surface of the formed charge after installation.

[0046] The bottom plate of the nozzle light shield 5 is also provided with a threaded hole for connecting with the nozzle 4. N When the diameter is less than 10mm, four threaded holes are symmetrically processed on the bottom plate of the nozzle light shield 5 along the circumference. When the diameter is greater than or equal to 10mm, six threaded holes are symmetrically processed on the bottom plate of the nozzle light shield 5 along the circumference. The size d of the threaded hole shall not be less than the discharge diameter D of the nozzle 4. N The roughness of the inner surface of the nozzle cover 5 and the nozzle 4 should be less than Ra 6.3, and the surface roughness of the flange of the nozzle cover 5 in contact with the medicine surface should be less than Ra 3.2, which is conducive to cleaning the solidified medicine residue on the surface of the nozzle cover 5.

[0047] This structure has been used many times in 3D printing solid propellant tests. The results show that there is no material residue on the nozzle surface after printing, and the anti-clogging effect of printing is significant.

[0048] The contents not described in detail in the specification of the present invention belong to the prior art known to those skilled in the art.

Claims

1. A high reliability solid propellant 3D printing curing device, characterized in that include: A solid propellant 3D printing nozzle structure, an ultraviolet lamp (6) and a printing platform (7); wherein the solid propellant 3D printing nozzle structure operates on the printing platform (7), and the ultraviolet lamp (6) is located outside the printing platform (7) and is used to solidify the solid propellant slurry; specifically: The solid propellant 3D printing nozzle structure comprises: a plunger (1), a barrel (2), a rubber sealing gasket (3), a nozzle (4), and a nozzle light shield (5); wherein: The plunger (1) is inserted from the rear end of the barrel (2) to extrude the solid propellant slurry; The other end of the barrel (2) is a discharge end, and a skirt plate is provided at the end; The nozzle (4) is a truncated cone structure, the discharge port is located at the top of the truncated cone, a skirt plate structure that matches the skirt plate of the barrel (2) is provided at the bottom of the truncated cone structure, a rubber sealing gasket (3) is provided between the barrel (2) and the skirt plate of the nozzle (4), and the barrel (2), the rubber sealing gasket (3) and the nozzle (4) are connected and fixed by bolts; The nozzle light shield (5) comprises a bottom plate, a sleeve and a flange, wherein the sleeve fits the side wall of the cone of the nozzle (4), the bottom plate fits the surface of the skirt at the bottom of the nozzle (4), and the flange is close to the discharge port of the nozzle (4).

2. A high reliability solid propellant 3D printing and curing device according to claim 1, characterized in that: The ultraviolet lamp (6) is fixed by an adjustable bracket, and the illumination power is greater than or equal to 160W; The angle α between the light and the upper surface of the printing platform is 30 to 60°. Specifically, when the height of the processing component is less than 50 mm, 30° is taken; when the height of the processing component is higher than 120 mm, 60° is taken.

3. A high reliability solid propellant 3D printing and curing device according to claim 1, characterized in that: The nozzle cover (5) is made of a dark opaque material, which does not react with ethyl acetate, is heat-resistant and does not decompose at 60±10° C., and has an elastic modulus of not less than 1000 MPa.

4. A high reliability solid propellant 3D printing and curing device according to claim 1, characterized in that: The minimum thickness t of the nozzle light shield (5) is 0.5 mm, and the diameter D of the nozzle (4) outlet port is N When it is greater than 10mm, the minimum thickness t is 1 to 2mm.

5. A high-reliability solid propellant 3D printing and curing device according to claim 1, characterized in that: Nozzle (4) discharge diameter D N When the diameter is less than 10 mm, two UV lamps (6) are arranged; D N When the diameter is larger than 10 mm, 4 to 6 ultraviolet lamps (6) are arranged.

6. A high-reliability solid propellant 3D printing and curing device according to claim 5, characterized in that: When two ultraviolet lamps (6) are arranged, the diameter D of the large circle at the outer end of the flange of the nozzle light shield (5) is H The diameter D of the nozzle (4) N When 4 to 6 ultraviolet lamps (6) are arranged, the light intensity increases with the increase in the number of ultraviolet lamps (6), and the large circle diameter D of the outer end of the nozzle light shield (5) is increased. H D N 5 to 15 times of.

7. A high reliability solid propellant 3D printing and curing device according to claim 1, characterized in that: The flange of the nozzle light shield (5) is not parallel to the bottom plate of the nozzle light shield (5), and the angle θ of the outer side of the flange tilting toward the bottom plate is 0-15° to avoid scratching the surface of the formed charge column after installation.

8. A high-reliability solid propellant 3D printing and curing device according to claim 7, characterized in that: Define the total length L of the nozzle (4) N is the distance from the skirt surface of the nozzle (4) to the plane where the discharge port is located; Define the nozzle shield (5) length L H It is the distance from the bottom plate to the plane where the flange turning position is located; Nozzle hood (5) length L H Than the total length L of the nozzle (4) N 1% to 5% shorter.

9. A high reliability solid propellant 3D printing and curing device according to claim 1, characterized in that: The bottom plate of the nozzle light shield (5) is also provided with a threaded hole for connecting with the nozzle (4). N When the diameter is less than 10 mm, four threaded holes are symmetrically processed along the circumference of the bottom plate of the nozzle light shield (5), and the discharge port diameter D N When the diameter is greater than or equal to 10 mm, six threaded holes are symmetrically processed on the bottom plate of the nozzle light shield (5) along the circumferential direction; The threaded hole size d must not be smaller than the nozzle (4) outlet diameter D N 10% of.

10. A high-reliability solid propellant 3D printing and curing device according to claim 1, characterized in that: The roughness of the inner surface of the nozzle light shield (5) where it fits the nozzle (4) is less than Ra 6.3, and the surface roughness of the flange of the nozzle light shield (5) in contact with the medicine surface is less than Ra 3.2, which is conducive to cleaning the solidified medicine slurry residue on the surface of the nozzle light shield (5).

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