A desktop 3D printing vertical double screw extrusion device for energetic materials

Abstract

The present application belongs to the field of 3D printing of energetic materials, and particularly relates to a desktop 3D printing vertical double-screw extrusion device for energetic materials. The device comprises a driving motor, a gear transmission mechanism, a conveyor belt, a barrel, and non-conjugate counter-rotating double screws arranged in the barrel. One end of the driving shaft of the gear transmission mechanism is connected with the driving motor, and the other end is connected with one end of one screw of the non-conjugate counter-rotating double screws. The driving shaft drives the driven shaft I to rotate through the gear, and the driven shaft I drives the driven shaft II to rotate through the transmission belt. One end of the driven shaft II is connected with one end of the other screw of the non-conjugate counter-rotating double screws. The device has good extrusion capacity, mixing capacity, low energy consumption, and continuous extrusion and printing capacity, and can print energetic materials with granular or powdery raw materials, continuously feed, have sufficient extrusion force, high-precision printing of energetic materials, and fast cleaning of the barrel.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of 3D printing of energetic materials, and particularly relates to a vertical double-screw extrusion device for desktop 3D printing of energetic materials. BACKGROUND

[0002] 3D printing forming technology, also known as additive manufacturing technology, is based on a digital model file, and uses a molten body, powder, wire or sheet of special materials such as metal and plastic which can be bonded to perform layer-by-layer bonding and stacking to form a three-dimensional entity. The 3D printing technology does not require machining or any mold, and can directly generate parts of any shape from computer data, has good adaptability, can greatly shorten the product development cycle, improve productivity and reduce production cost, and is gradually applied to industries such as mold building, aerospace, and biomedical.

[0003] Energetic materials are a class of compounds or mixtures with explosive groups or oxidizing agents and combustible materials, which can independently undergo chemical reactions and release a large amount of energy, gas and heat under the stimulation of external energy. Energetic materials play an indispensable role in the military field, and are widely used in the reaction propulsion, explosion work and pressure propulsion of various weapon fire systems. The application of 3D printing technology to the forming field of energetic materials combines the adaptability of energetic materials with the forming principle of 3D printing, which can solve the defects of poor adaptability of traditional energetic material forming process to complex and special-shaped grain columns while realizing moldless forming, and can adapt to energetic material grain of various shapes.

[0004] Currently, the 3D printing of energetic materials is mainly based on plunger extrusion and single-screw extrusion. The main disadvantage of the plunger extrusion of 3D printing of energetic materials is that it cannot be continuously extruded, and the material needs to be replaced in the middle, and the material needs to be cleaned before replacement. When forming energetic material with small energy output, such as some types of gunpowder or low-sensitivity explosive material parts, a screw desktop extrusion device is generally used. When the single-screw extrusion of 3D printing of energetic materials is formed, although continuous extrusion can be realized, materials with high viscosity are prone to cause material cylinder blockage due to insufficient extrusion force. SUMMARY

[0005] The purpose of the present application is to provide a vertical double-screw extrusion device for desktop 3D printing of energetic materials, which can simultaneously satisfy continuous extrusion and sufficient extrusion force, and reduce the situation of nozzle blockage caused by insufficient extrusion force.

[0006] The technical solution for achieving the purpose of the present application is: a vertical double-screw extrusion device for desktop 3D printing of energetic materials, comprising a driving motor, a gear transmission mechanism, a conveyor belt, a material cylinder, and a non-conjugate heterodirectional double screw arranged in the material cylinder.

[0007] The driving shaft of the gear transmission mechanism is connected with the driving motor at one end and with one end of one screw rod in the non-conjugate and opposite direction double screw rod at the other end; the driving shaft drives the driven shaft I to rotate through the gear; the driven shaft I drives the driven shaft II to rotate through the transmission belt; the other end of the driven shaft II is connected with the other screw rod in the non-conjugate and opposite direction double screw rod.

[0008] Further, the horizontal beam, the opposite stand plates I and II arranged on the horizontal beam, the upper fixed plate arranged between the stand plates I and II, the middle fixed plate, the lower fixed plate and the driven shaft II fixed plate arranged above the lower fixed plate are further included.

[0009] The driving shaft is connected with the driving motor through the shaft coupling at one end; the driving shaft is connected with the screw rod at one end after sequentially penetrating through the middle fixed plate, the driven shaft II fixed plate and the lower fixed plate; the driving shaft is connected with the middle fixed plate through the bearing; the upper and lower ends of the driven shaft I are connected with the upper fixed plate and the lower fixed plate through the bearing III and the bearing I respectively; the upper and lower ends of the driven shaft II are connected with the driven shaft II fixed plate and the lower fixed plate through the bearing IV and the bearing II respectively.

[0010] Further, the funnel buckle and the feeding funnel are further included.

[0011] The feeding funnel is fixed on the funnel buckle and connected with the horizontal beam; the feeding funnel conveys the energetic material into the barrel.

[0012] Further, the lower thick plate is arranged below the horizontal beam; the barrel is connected with the lower thick plate; the lower rib plate is arranged below the lower thick plate.

[0013] Further, the pair of non-conjugate and opposite direction double screw rods are connected with the driving shaft and the driven shaft II through the positioning cylindrical pin.

[0014] Further, the detachable nozzle with the temperature control system is further included; the detachable nozzle with the temperature control system includes the heating rod, the temperature measuring probe and the extrusion nozzle.

[0015] Further, the transport section electric heating wire heating device, the melting end electric heating wire heating device and the metering section electric heating wire heating device are sequentially arranged on the outer periphery of the barrel from top to bottom.

[0016] The heat insulation sleeve I is arranged between the upper end of the transport section electric heating wire heating device and the barrel; the heat insulation sleeve II is arranged between the transport section electric heating wire heating device and the melting end electric heating wire heating device; the heat insulation sleeve III is arranged between the melting end electric heating wire heating device and the metering section electric heating wire heating device; the heat insulation bottom plate is arranged between the metering section electric heating wire heating device and the detachable nozzle with the temperature control system.

[0017] Further, the barrel cleaning device is further included; the barrel cleaning device includes the cleaning conveying pipeline and the water pipe.

[0018] Compared with the prior art, the present application has the following advantages:

[0019] (1) The application adopts double screw instead of single screw, the extrusion force of double screw is much higher than that of single screw, which improves the extrusion efficiency; by adopting an additional driven shaft and a conveying belt, the distance between the driving shaft and the driven shaft I is not affected by the distance between the double screws, so that the gear size between the driving shafts can be increased accordingly, the larger gear has stronger wear resistance, which improves the gear life and reduces the maintenance cost.

[0020] (2) After 3D printing is completed, the barrel cleaning device can quickly clean the barrel to facilitate subsequent printing or printing of other energetic materials. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a structural schematic diagram of the explosion view of the vertical double screw extrusion transmission part of the energetic material 3D printing of the application.

[0022] Figure 2 is a structural schematic diagram of the explosion view of the vertical double screw extrusion device of the energetic material 3D printing of the application.

[0023] Figure 3 is a structural schematic diagram of the front view of the vertical double screw extrusion of the energetic material 3D printing of the application.

[0024] BRIEF DESCRIPTION OF DRAWINGS

[0025] 1-stand plate I, 2-bearing I, 3-bearing II, 4-hopper buckle, 5-positioning cylindrical pin, 6-feeding hopper, 7-lower thick plate, 8-non-conjugate dissimilar double screw, 9-lower rib plate, 10-heat insulation sleeve I, 11-heat insulation sleeve II, 12-heat insulation sleeve III, 13-heat insulation bottom plate, 14-barrel, 15-dismountable nozzle with temperature control system, 16-driving motor, 17-bearing III, 18-upper fixed plate, 19-coupling, 20-driven shaft I, 21-driving shaft, 22-driven gear, 23-driving gear, 24-middle fixed plate, 25-stand plate II, 26-bearing IV, 27-driven shaft II fixed plate, 28-conveying belt, 29-driven shaft II, 30-water pipe, 31-lower fixed plate, 32-cleaning conveying pipeline, 33-cross beam, 34-conveying section electric heating wire heating device, 35-melting end electric heating wire heating device, 36-metering section electric heating wire heating device. DETAILED DESCRIPTION

[0026] The application will be further described in detail below with reference to the drawings.

[0027] The application discloses a vertical double screw extrusion device for energetic material 3D printing, in order to better illustrate the action of the extrusion device, the composition and working condition thereof are briefly described.

[0028] The main components of the energetic material 3D printing vertical double screw extrusion device are as follows:Figure 1 and Figure 2 As shown, the vertical twin-screw extruder for energetic material 3D printing includes a gear belt drive, a feeding funnel device, a pair of non-conjugate counter-rotating twin screws, a barrel, a three-section barrel heating element, a detachable nozzle with a temperature control system, and a barrel cleaning device. The gear belt drive includes a drive motor 16 connected to a drive shaft 21 via a coupling 19. The drive shaft 21 is fixed to a drive gear 23. A driven shaft I 20 is fixed to a driven gear 22. The driven shaft I 20 engages with a bottom bearing I 2 and also with a top bearing III 17. Driven shafts I 20 and II 29 are driven by a belt 28. The driven shaft II 29 engages with a bottom bearing II 3 and a top bearing IV 26. The feeding funnel device includes a funnel buckle 4 and a feeding funnel 6. The feeding funnel 6 is fixed to the funnel buckle 4, which is connected to a crossbeam 33. A pair of non-conjugate, opposite-direction twin screws 8 are connected to the drive shaft 21 and the driven shaft II 30 via positioning cylindrical pins 5. The barrel 14 is connected to the lower thick plate 7, the lower stiffening plate 9 is connected to the conveying section heating element 34, and the barrel 14 is connected to the three-section barrel heating element. The barrel 14 is connected to the insulation sleeve I 10, insulation sleeve II 11, insulation sleeve III 12, and insulation base plate 13. The three-section barrel heating element includes the conveying section heating element 34, the melting end heating element 35, and the metering section heating element 36. The detachable nozzle 15 with a temperature control system includes a heating rod, a temperature probe, and an extrusion nozzle. The barrel cleaning device includes a cleaning conveying pipe 32 connected to a water pipe 30.

[0029] like Figure 1 and Figure 2 As shown, in the vertical twin-screw extruder for energetic material 3D printing, the motor 16 rotates, driving the drive shaft 21 to rotate. The drive gear 23, fixed to the drive shaft 21, rotates, meshing with the driven gear 22, which in turn drives the driven gear 22 to rotate. The driven gear 22 is fixed to the driven shaft I 20, driving the driven shaft I 20 to rotate. The driven shaft I 20 and driven shaft II 29 transmit torque through the conveyor belt 28, driving the driven shaft II 29 to rotate. The drive shaft 21 is fixed to the right screw by a locating cylindrical pin, and the driven shaft II 29 is fixed to the left screw by a locating cylindrical pin 5. Driven by the motor, the non-conjugate, counter-rotating twin screws 8 can rotate counter-rotatingly to mix the material. In desktop twin-screw extruders, the distance between the screws is small. If direct gear meshing is used, the gear diameter and number of teeth are limited, and the smaller gear has a short lifespan. A gear belt drive can use larger gears, improving gear lifespan.

[0030] like Figure 2As shown, the four-section heat insulation sleeve wrapped outside the barrel is to reduce heat loss and energy consumption. The conveying section electric heating wire heating device 34, the melting end electric heating wire heating device 35 and the metering section electric heating wire heating device 36 realize complete melting of the energetic material in the barrel without explosion by controlling the current size of the electric heating wire. Finally, the detachable nozzle 15 with temperature control system can accurately control the extrusion temperature to ensure the molding precision. The detachable nozzle 15 with temperature control system can replace the nozzle diameter to adapt to different printing precision requirements.

[0031] As shown in the figure, Figure 3 After the printing of the energetic material is completed, the barrel will be left with residual energetic material. After the printing is completed, the cleaning device is used to inject water into the barrel, and the non-conjugate counter-rotating twin screw 8 is rotated at the same time, and the residual energetic material in the barrel can flow out, realizing rapid cleaning to facilitate the next printing.

[0032] The working process of the present application is: the STL format three-dimensional model is sliced by using slicing software to generate G-code code, and the G-code code is transmitted into the development board to perform energetic material 3D printing. The granular or powdered energetic material is sent into the material inlet through the feeding mechanism, stirred through the double screw mechanism, heated into a molten state through the barrel, extruded through the temperature control nozzle on the hot bed, so that the cooling speed is stable, and finally the energetic material 3D printing is completed. After 3D printing is completed, the barrel cleaning device can quickly clean the barrel.

[0033] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A desktop 3D printing vertical twin-screw extrusion device for energetic materials, characterized in that, It comprises a driving motor (16), a gear transmission mechanism, a conveyor belt (28), a barrel (14), and a non-conjugate counter-rotating twin screw (8) arranged in the barrel (14); One end of the driving shaft (21) of the gear transmission mechanism is connected with the driving motor (16) and one end of one screw of the non-conjugate counter-rotating twin screw (8); the driving shaft (21) drives the driven shaft I (20) to rotate through a gear, the driven shaft I (20) drives the driven shaft II (29) to rotate through a transmission belt (28), and one end of the driven shaft II (29) is connected with the other screw of the non-conjugate counter-rotating twin screw (8); It also comprises a detachable nozzle (15) with a temperature control system, which comprises a heating rod, a temperature measuring probe and an extrusion nozzle; It also comprises a conveying section electric heating wire heating device (34), a melting end electric heating wire heating device (35) and a metering section electric heating wire heating device (36) arranged in sequence from top to bottom on the outer periphery of the barrel (14); A heat insulation sleeve I (10) is arranged between the upper end of the conveying section electric heating wire heating device (34) and the barrel (14), a heat insulation sleeve II (11) is arranged between the conveying section electric heating wire heating device (34) and the melting end electric heating wire heating device (35), a heat insulation sleeve III (12) is arranged between the melting end electric heating wire heating device (35) and the metering section electric heating wire heating device (36), and a heat insulation bottom plate (13) is arranged between the metering section electric heating wire heating device (36) and the detachable nozzle (15) with a temperature control system.

2. The apparatus of claim 1, wherein, It also comprises a cross beam (33), opposite stand plates I (1) and II (25) arranged on the cross beam (33), an upper fixed plate (18), a middle fixed plate (24), a lower fixed plate (31) arranged between the stand plates I (1) and II (25), and a driven shaft II fixed plate (27) arranged above the lower fixed plate (31); One end of the driving shaft (21) is connected with the driving motor (16) through a shaft coupling (19), the driving shaft (21) is connected with one end of the screw after passing through the middle fixed plate (24), the driven shaft II fixed plate (27) and the lower fixed plate (31) in sequence, and the driving shaft (21) is connected with the middle fixed plate (24) through a bearing; the upper and lower ends of the driven shaft I (20) are connected with the upper fixed plate (18) and the lower fixed plate (31) through a bearing III (17) and a bearing I (2), respectively; the upper and lower ends of the driven shaft II (29) are connected with the driven shaft II fixed plate (27) and the lower fixed plate (31) through a bearing IV (26) and a bearing II (3), respectively.

3. The apparatus of claim 2, wherein, It also comprises a hopper buckle (4) and a feeding hopper (6); The feeding hopper (6) is fixed on the hopper buckle (4), the hopper buckle (4) is connected with the cross beam (33), and the feeding hopper (6) conveys the energetic material into the barrel (14).

4. The apparatus of claim 3, wherein, A lower thick plate (7) is arranged below the cross beam (33), the barrel (14) is connected with the lower thick plate (7), and a lower rib plate (9) is arranged below the lower thick plate (7).

5. The apparatus of claim 4, wherein, A pair of non-conjugate counter-rotating twin screws (8) are connected with the driving shaft (21) and the driven shaft II (29) through positioning cylindrical pins (5).

6. The apparatus of claim 5, wherein, It also comprises a barrel cleaning device, which comprises a cleaning conveying pipeline (32) and a water pipe (30).

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