A high-reliability solid propellant 3D printing curing device

Abstract

The application discloses a kind of high reliability solid propellant 3D printing solidification equipment, including solid propellant 3D printing nozzle structure, ultraviolet light and printing platform;High reliability solid propellant 3D printing nozzle structure includes: plunger, cartridge, rubber sealing gasket, nozzle, nozzle light shield.When solid propellant printing is carried out, plunger extrudes solid propellant slurry in cartridge and is extruded from nozzle, and photocuring equipment irradiates printed slurry and carries out photocuring setting, and light shield is installed at nozzle connection, to avoid that solid propellant is formed in the vicinity of nozzle discharge hole and is solidified and is blocked.The application is widely applicable, and can realize that solid propellant is uniformly, efficiently and stably solidified and formed.

Description

TECHNICAL FIELD

[0001] The application relates to a high-reliability solid propellant 3D printing and curing device and belongs to the technical field of aerospace power. BACKGROUND

[0002] 3D printing is an entity manufacturing technology for realizing material forming through layer-by-layer accumulation, and has obvious advantages in manufacturing complex components and special structures, and is changing the production mode of solid propellant grain as a leading manufacturing technology. When 3D printing solid propellant, premixed slurry is injected into a barrel, and is extruded through a nozzle to realize layer-by-layer accumulation of the slurry. With the aid of curing forming means (such as light curing and heat curing auxiliary forming), the surface of the slurry can be cured in time after extrusion, so that the slurry has a certain shape-retaining support capability, so as to avoid the collapse of the solid propellant slurry accumulation.

[0003] The nozzle is a key component of solid propellant 3D printing, and directly affects the printing efficiency and the performance of the solid propellant after printing. Reasonable nozzle design should ensure that the slurry is continuously and stably extruded, and has good compatibility with light curing auxiliary equipment, so as to avoid problems such as the nozzle not working normally due to light curing process, or poor light curing effect and structure collapse caused by the nozzle.

[0004] At present, there are many technical bottlenecks in the 3D printing and forming of solid propellant, such as printing and forming collapse and nozzle blockage. The former is due to incomplete and slow solidification of solid propellant, which cannot provide effective support for the upper layer printing, and the latter is due to the blockage of the outlet of the nozzle caused by the solidification of the slurry near the nozzle under the irradiation of ultraviolet light. Cleaning the blockage is easy to cause irreversible damage to the nozzle, and the process safety cannot be guaranteed.

[0005] Related scholars have done a lot of work on the 3D printing technology of solid propellant and the design of the nozzle. Patent 'Anti-blocking structure of nozzle for 3D printing' (CN202122127501.4) sets an axially movable nozzle and a fixed insertion rod (both coaxial), and when the nozzle is blocked, the insertion rod is inserted into the nozzle by moving the nozzle axially, so as to clean the nozzle blockage. Patent '3D printer nozzle with stable heating and heat dissipation' (CN202320541126.4) loads a stable thermal environment at the nozzle to prevent the slurry from solidifying and causing blockage at the nozzle, and the effect is remarkable. However, in the process of printing solid propellant, the mechanical unblocking anti-blocking structure is easy to cause friction fire, and direct heating of the nozzle is easy to cause local overheating and ignite, so the production safety and reliability cannot be guaranteed, and a nozzle that can avoid solidification and blockage at the nozzle is also needed when the solid propellant is light cured. SUMMARY

[0006] The technical solution of the present application is: to overcome the shortcomings of the prior art, a high-reliability solid propellant 3D printing curing equipment is provided, which is widely applicable, uniform and efficient in photocuring, and provides technical accumulation for 3D printing forming in the field of solid propellant manufacturing.

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

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

[0009] The plunger is inserted from the tail end of the barrel for extruding the solid propellant slurry;

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

[0011] The nozzle is a circular truncated cone structure, the discharge port is located at the top end of the circular truncated cone, the bottom of the circular truncated cone structure is provided with a skirt plate structure matched with the skirt plate of the barrel, the rubber sealing gasket is arranged between the skirt plates of the barrel and the nozzle, and the barrel, the rubber sealing gasket and the nozzle are connected and fixed by bolts;

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

[0013] Preferably, the ultraviolet light is fixed by an adjustable support, and the illumination power is greater than or equal to 160W;

[0014] The included angle a between the light and the upper surface of the printing platform is 30-60°, specifically: 30° when the height of the processed part is less than 50mm, and 60° when the height of the processed part is greater than 120mm.

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

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

[0017] Preferably, the diameter D of the nozzle discharge port is less than 10mm. N When the diameter D of the nozzle discharge port is less than 10mm, two ultraviolet lights are arranged; D N When the diameter D of the nozzle discharge port is greater than 10mm, 4-6 ultraviolet lights are arranged.

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

[0019] Preferably, the flange of the nozzle shield is not parallel to the base plate of the nozzle shield, and the angle θ of the outer side of the flange pointing towards the base plate is 0 to 15° to avoid rubbing against the surface of the molded propellant column after installation.

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

[0021] Define the nozzle shield length L H This is the distance from the base plate to the plane where the flange turns;

[0022] Nozzle shield length L H Length L of nozzle N Shorter by 1% to 5%.

[0023] Preferably, the base plate of the nozzle shield is also provided with a threaded hole for connecting with the nozzle, when the nozzle outlet diameter D N When the diameter is less than 10mm, four threaded holes are symmetrically machined along the circumference on the base plate of the nozzle shield, with a discharge port diameter D. N When the diameter is greater than or equal to 10mm, six threaded holes are symmetrically machined along the circumference on the base plate of the nozzle shield.

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

[0025] Preferably, the surface roughness of the inner surface of the nozzle shield where it mates with the nozzle is less than Ra 6.3, and the surface roughness of the flange of the nozzle shield in contact with the drug surface is less than Ra 3.2, which is beneficial for cleaning the solidified drug residue on the surface of the nozzle shield.

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

[0027] (1) The surface quality of the molded parts is improved by the present invention. During the printing process, the ultraviolet lamp enables the slurry to solidify rapidly, so that the solid propellant after the lower layer is solidified can provide effective support for the upper layer of printing, thus avoiding the structural collapse problems caused by slow curing speed, shallow curing degree and uneven curing;

[0028] (2) The printing process has good continuity and high stability. In view of the nozzle outlet clogging problem during photocuring, a light shield suitable for the nozzle is designed to shield the nozzle outlet; the light shield has moderate size, which can effectively shield light while having little influence on the photocuring of the slurry, thereby avoiding photocuring dead angles;

[0029] (3) The present application has low energy consumption, low cost and is convenient for operators to observe. The existing photocuring equipment is generally fixed inside the printing frame to realize full coverage of the printing area, which requires high power and often needs four or more high-power ultraviolet lamps, and is not conducive to real-time observation by operators. The photocuring auxiliary equipment of the present application can adjust the irradiation angle according to the needs, and the light only irradiates the parts to be cured, reducing light waste and light pollution, and the light shield structure is simple, easy to process and low in cost.

[0030] (4) The present application has good reliability and high safety. After installing the structure, non-contact processing can be realized, without using mechanical dredging or direct heating type anti-clogging devices, which avoids spontaneous combustion of solid propellants during printing and ensures processing safety. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a schematic diagram of the nozzle structure of the present application;

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

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

[0034] IDENTIFICATION OF DRAWINGS:

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

[0036] In order to illustrate the technical solutions and technical purposes of the present application, the present application will be further described below in combination with the drawings and specific embodiments.

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

[0038] High reliability solid propellant 3D printing nozzle structure, including plunger 1, barrel 2, rubber sealing gasket 3, nozzle 4, nozzle light shield 5. Plunger 1 is inserted from the tail end of barrel 2, for extruding solid propellant slurry;The discharge end of barrel 2 is provided with a skirt plate;Nozzle 4 is a circular truncated cone structure, and the discharge port is located at the top of the circular truncated cone, and the bottom of the circular truncated cone is provided with a skirt plate structure matched with the skirt plate of barrel 2, and corresponding screw holes are arranged on the skirt plates of barrel 2 and nozzle 4, and rubber sealing gasket 3 is arranged between the skirt plates, and barrel 2, rubber sealing gasket 3 and nozzle 4 are connected and fixed by bolts.

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

[0040] Ultraviolet lamp 6 is located outside the printing platform 7, for curing the solid propellant slurry.

[0041] When printing solid propellant, plunger 1 extrudes the solid propellant slurry in barrel 2 from nozzle 4, ultraviolet lamp 6 irradiates the printed slurry for photocuring and shaping, nozzle light shield 5 is sleeved on nozzle 4 to avoid the solid propellant from being cured to form blockage near the discharge port of nozzle 4. The overall structure of the printing equipment is shown in Figure 2 .

[0042] In the structure of the application, the ultraviolet lamp 6 for curing the material should be arranged outside the printing platform 7 and fixed on the bottom of the printing equipment by an adjustable support, the upper surface of the printing platform is disc-shaped, the maximum diameter of the disc is not higher than 400 mm, as shown by the dotted line in Figure 2 , the illumination angle α (the angle between the light and the upper surface of the printing platform) should be between 30-60°, 30° when the height of the processed part is lower than 50 mm, and 60° when the height of the processed part is higher than 120 mm, the wavelength of the ultraviolet lamp is selected according to the formula, and the illumination power is selected to be 160W or above.

[0043] The structure of nozzle light shield 5 is a key component for preventing nozzle blockage, as shown in Figure 3 , the nozzle shield 5 should be made of dark non-light-transmitting material, such as plastic, rubber, latex and other non-metallic materials, the material should not react with ethyl acetate, and should not decompose at 60±10℃, so as to prevent damage when cleaning the surface of the nozzle, and the elastic modulus of the material should be not less than 1000MPa.

[0044] The minimum thickness t of nozzle light shield 5 is 0.5mm, the diameter D N of the discharge port of nozzle 4 is greater than 10mm, the minimum thickness t is 1-2mm, the large circle diameter D H of the outer end of the flange of nozzle light shield 5 is 3-10 times the diameter D N of the discharge port of nozzle 4;The diameter D NWhen the diameter is less than 10 mm, two UV lamps 6 are arranged in the circumferential direction for curing the material, and D N When the diameter is greater than 10 mm, 4-6 UV lamps 6 are arranged in the circumferential direction, and the light intensity is increased while the lower diameter D is appropriately increased H D is 1-3 times the diameter, and at this time D H D can be selected in the range of 5xD N -15xD N ;

[0045] The total length L of the nozzle (4) is defined as the distance from the bottom plate to the plane where the turning position of the flange is located N The length L of the nozzle light shield (5) is defined as the distance from the bottom plate to the plane where the turning position of the flange is located H The length L of the nozzle light shield (5) is defined as the distance from the bottom plate to the plane where the turning position of the flange is located H The length L of the nozzle light shield (5) is defined as the distance from the bottom plate to the plane where the turning position of the flange is located N The length L of the nozzle light shield (5) is defined as the distance from the bottom plate to the plane where the turning position of the flange is located

[0046] The bottom plate of the nozzle light shield (5) is also provided with a threaded hole for connecting with the nozzle (4), and when the diameter D of the discharge port of the nozzle (4) is less than 10 mm, 4 threaded holes are symmetrically machined on the bottom plate of the nozzle light shield (5) in the circumferential direction, and when the diameter D of the discharge port of the nozzle (4) is greater than or equal to 10 mm, 6 threaded holes are symmetrically machined on the bottom plate of the nozzle light shield (5) in the circumferential direction, and the size d of the threaded hole should not be less than 10% of the diameter D of the discharge port of the nozzle (4). N The roughness of the inner surface of the nozzle shield (5) should be less than Ra 6.3, and the roughness of the surface of the flange of the nozzle light shield (5) in contact with the propellant surface should be less than Ra 3.2, which is beneficial to cleaning the nozzle light shield (5) surface propellant curing residue. N The structure has been used for 3D printing of solid propellant test for many times, and the results show that there is no material residue on the nozzle surface after printing, and the printing anti-blocking effect is remarkable.

[0047] The contents not described in detail in the specification of the present application belong to the prior art known to those skilled in the art.

[0048] The contents not described in detail in the specification of the present application 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: The solid propellant 3D printing nozzle structure, ultraviolet lamp (6), and printing platform (7) are used; the solid propellant 3D printing nozzle structure is operated on the printing platform (7), and the ultraviolet lamp (6) is located outside the printing platform (7) to solidify the solid propellant slurry; specifically: The 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); wherein: The plunger (1) is inserted from the tail end of the barrel (2) to extrude solid propellant slurry; The other end of the material cylinder (2) is the discharge end, and the port is equipped with a skirt plate; The nozzle (4) is a frustum structure with the outlet located at the top of the frustum. The bottom of the frustum structure is provided with a skirt structure that cooperates with the skirt of the barrel (2). There is a rubber sealing gasket (3) between the skirts of the barrel (2) and the nozzle (4). The barrel (2), the rubber sealing gasket (3) and the nozzle (4) are connected and fixed by bolts. The nozzle shield (5) includes a base plate, a sleeve and a flange. The sleeve fits against the side wall of the truncated cone of the nozzle (4), the base plate fits against the skirt surface at the bottom of the nozzle (4), and the flange is close to the outlet of the nozzle (4). The ultraviolet lamp (6) is fixed by an adjustable bracket and has a light power of ≥160 W; The angle α between the light and the upper surface of the printing platform is 30~60°. Specifically, 30° is used when the height of the part being processed is less than 50 mm, and 60° is used when the height of the part being processed is greater than 120 mm.

2. The high-reliability solid propellant 3D printing curing equipment according to claim 1, characterized in that: The nozzle shield (5) is made of dark, opaque material that does not react with ethyl acetate and is heat-resistant and does not decompose at 60±10℃. The elastic modulus of the material is not less than 1000 MPa.

3. The high-reliability solid propellant 3D printing curing equipment according to claim 1, characterized in that: Minimum thickness of nozzle shield (5) t It is 0.5 mm.

4. The high-reliability solid propellant 3D printing curing equipment according to claim 1, characterized in that: Nozzle (4) discharge port diameter D N When the thickness is greater than 10 mm, t Take 1~2 mm.

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

6. The high-reliability solid propellant 3D printing curing equipment according to claim 5, characterized in that: When arranging two ultraviolet lamps (6), the large circle diameter of the outer edge of the nozzle shield (5) is... D H For nozzle (4) discharge port diameter D N The light intensity increases by 3 to 10 times when 4 to 6 UV lamps (6) are arranged. When the number of UV lamps (6) increases, the large circle diameter of the outer edge of the nozzle shield (5) should be increased. D H for D N 5 to 15 times.

7. The high-reliability solid propellant 3D printing curing equipment according to claim 1, characterized in that: The flange of the nozzle shield (5) is not parallel to the base plate of the nozzle shield (5), and the outer side of the flange is raised towards the base plate at an angle. θ Use an angle of 0~15° to avoid scratching the surface of the molded propellant column after installation.

8. The high-reliability solid propellant 3D printing curing equipment according to claim 7, characterized in that: Define the total length of the nozzle (4) L N The distance from the surface of the nozzle (4) skirt to the plane where the discharge port is located; Define the length of the nozzle shroud (5) L H This is the distance from the base plate to the plane where the flange turns; Nozzle shield (5) length L H Total length of nozzle (4) L N Shorter by 1% to 5%.

9. The high-reliability solid propellant 3D printing curing equipment according to claim 1, characterized in that: The base plate of the nozzle shield (5) is also provided with threaded holes for connecting with the nozzle (4). When the nozzle (4) discharge port diameter D N When the diameter is less than 10mm, four threaded holes are symmetrically machined along the circumference on the base plate of the nozzle shield (5), and the discharge port diameter is... D N When the diameter is greater than or equal to 10 mm, six threaded holes are symmetrically machined along the circumference on the base plate of the nozzle shield (5); Threaded hole size d The discharge diameter shall not be less than that of nozzle (4). D N 10%.

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

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