Solid motor insulation layer whole 3D printing device and method based on light-heat composite curing system

Abstract

The application discloses a kind of based on light-thermal composite curing system's solid motor heat-insulating layer whole 3D printing device and method, accurate positioning printing position is positioned by adopting the device of multidimensional stepping and rotating mechanical structure, heat-insulating layer slurry is printed in engine shell inner surface layer by layer, preliminary setting and curing are carried out to ternary ethylene-propylene material by the ultraviolet light source integrated in the front end of device in printing process, so that the heat-insulating layer printed layer by layer does not appear to flow deformation and other phenomena, after heat-insulating layer whole printing is completed, heat-insulating layer is molded and vulcanized setting, and engine heat-insulating layer manufacturing is completed.The method improves the quality control difficulty, long construction period and high cost problem in heat-insulating layer artificial construction, overturns the construction process of traditional heat-insulating layer, and establishes a new heat-insulating construction method.It has the advantages of simple principle, high product yield, short construction period and quality controllable, and has good application prospect for the innovation of solid motor heat-insulating layer manufacturing process.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing technology, specifically relating to a solid engine insulation layer integral 3D printing device and method based on a photo-thermal composite curing system. Background Technology

[0002] The design of the insulation layer for solid rocket motors must fully consider the heat exposure time, erosion from the rear end cap, and overload corrosion. Different thicknesses of insulation layer are required at different locations to meet ablation requirements. Current insulation layer application typically involves manually placing prefabricated sheets and variable-thickness layers in designated locations, followed by complex processes such as adhesive application, molding, pre-curing, and vulcanization. This process heavily relies on the skill of the workers and the quality of the insulation sheets, making it a unique step in the manufacturing process. Problems such as air trapping or bulging during application can affect the insulation quality and lead to overall product defects.

[0003] The 3D printing method of photo-thermal composite curing system has been successfully applied to the printing and molding process of solid propellants and coating cylinders, and has been verified in ground tests. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, this invention provides a 3D printing device and method for a solid-state engine insulation layer based on a photo-thermal composite curing system. The device employs a multi-dimensional stepping and rotating mechanical structure to accurately position the printing location, printing the insulation slurry layer by layer onto the inner surface of the engine casing. During the printing process, an ultraviolet light source integrated at the front end of the device initially solidifies and shapes the EPDM material, preventing flow and deformation during layer-by-layer printing. After the insulation layer is printed, it undergoes molding and vulcanization for final shaping, completing the engine insulation layer manufacturing. This method improves upon the problems of difficult quality control, long construction cycles, and high costs associated with manual insulation layer construction, revolutionizing traditional insulation layer construction processes and establishing a completely new insulation construction method. It boasts advantages such as simple principle, high product yield, short construction cycle, and controllable quality, showing promising application prospects for the innovation of solid-state engine insulation layer manufacturing processes.

[0005] The technical solution adopted by this invention to solve its technical problem is as follows: A solid engine insulation layer integral 3D printing device based on photo-thermal composite curing system includes photocurable EPDM slurry, axial lead screw, axial stepper motor, radial hydraulic extension rod, rotary motor, axial flange fixing plate, replaceable material pipe, pressure hose, extrusion screw, printing nozzle, ultraviolet light source and miniature camera; After extrusion, the EPDM slurry is rapidly cured by an ultraviolet light source integrated into the print head to form a hard shell. It is then finally molded by hot vulcanization in a hot oven and pressing. The lead screw, radial hydraulic extension rod, and axial flange fixing plate constitute a frame system, providing rigid support for the axial stepper motor and rotary motor; the lead screw is the frame on the engine's axis of symmetry, used to position the axis and fix the radial hydraulic extension rod; the radial hydraulic extension rod is used for radial positioning, fixed on the lead screw, and can be positioned by extending and shortening; the axial flange fixing plates are respectively installed on the front and rear end flange faces of the engine, used to fix the lead screw; The axial stepper motor and the rotary motor constitute an actuation system, which works in conjunction with the frame system to achieve precise positioning and movement of the print head; the axial stepper motor is mounted on the lead screw and is used to change the axial position of the radial hydraulic extension rod; the rotary motor is mounted on the axial flange fixing plate and is used to rotate the lead screw to change the angle of the radial hydraulic extension rod. The replaceable raw material tube, pressure hose, extrusion screw, and printing nozzle constitute the raw material feeding system. The replaceable raw material tube is the slurry source and is designed to be replaceable, allowing replacement with a new replaceable raw material tube when it is no longer in use or when extrusion stops. The pressure hose is used to transport the slurry. The extrusion screw is a device that stably outputs slurry downstream of the replaceable raw material tube to the nozzle, and the slurry extrusion speed can be adjusted by controlling the screw speed. The printing nozzle is the discharge port, and the outlet slurry diameter is adjustable, allowing the printing output thickness to be changed according to the printing accuracy requirements. The ultraviolet light source is an illumination device integrated near the print head, capable of outputting ultraviolet light of a certain wavelength and power to irradiate the printing area and cause the surface of the slurry to undergo preliminary solidification and shaping.

[0006] The miniature camera is an image recording device integrated near the print head, capable of recording images during the printing process to assess print quality in real time.

[0007] Preferably, the photocurable EPDM slurry can achieve rapid photocuring under ultraviolet or visible light irradiation, so that the propellant printed in layers does not flow or deform.

[0008] Preferably, the photocurable EPDM slurry is made by adding a photosensitive resin that can be rapidly cured under ultraviolet light to EPDM material, and adding a photocurable diluent and a photoinitiator.

[0009] An installation method for a solid engine insulation layer integral 3D printing device based on a photo-thermal composite curing system includes the following steps: Step 1: Connect the axial stepper motor to the axial flange fixing plate, connect the axial lead screw to the axial stepper motor, install the rotary motor on the axial lead screw, connect the radial hydraulic extension rod to the rotary motor, and the printing frame is installed. Step 2: Secure the 3D printing frame to the engine housing using bolted flanges; Step 3: Install the print head, ultraviolet light source, and miniature camera before the extrusion screw, specifically at the front end of the hydraulic extension rod; Step 4: Pour the photocurable EPDM slurry into the raw material tube and install the raw material tube after the extrusion screw; Step 5: Connect the pressure hose to the raw material pipe and the air source. Installation is complete. A printing method for a solid engine insulation layer integral 3D printing device based on a photo-thermal composite curing system includes the following steps: Step 1: Pump the paste-like insulation layer slurry from the pressure hose to the extrusion screw. The extrusion screw, controlled by the motor, extrudes the slurry to the print head at a set speed, thus completing the material extrusion. Step 2: After the material is extruded, it is initially cured by the ultraviolet light source above the print head and the photoinitiator in the printing material. Step 3: During printing, the rotary motor controls the print head and the radial hydraulic extension rod in the circumferential printing position, the radial hydraulic extension rod controls the radial position of the print head, and the axial stepper motor adjusts the axial position of the print head through the control axis screw, thereby achieving precise control of the printing position; Step 4: The print head rotates and advances from the front end cap to the rear end cap, printing a certain thickness of insulation layer at each location it passes through until printing is complete.

[0010] The beneficial effects of this invention are as follows: 1) This invention has the advantages of high product yield, short construction period and controllable quality.

[0011] 2) This invention avoids the special process in traditional insulation manufacturing that relies on the skill level of workers, and the yield rate is guaranteed by automated equipment.

[0012] 3) The photo-thermal composite curing system proposed in this invention can pre-cur the slurry during the printing process through the photopolymerization reaction of ultraviolet light, preventing the slurry from flowing and deforming. After the overall printing is completed, it is molded and vulcanized using an airbag. This method features high yield and high quality consistency.

[0013] 3) The insulation layer manufacturing method proposed in this invention can significantly improve the production efficiency of insulation layers. In the mass production stage, multiple printers can be used to continuously produce high-quality insulation layer products to meet emergency response needs. Attached Figure Description

[0014] Figure 1 This is the overall design drawing of the present invention.

[0015] Figure 2 This is the design drawing of the printhead for this invention.

[0016] In the diagram: 1-Engine housing; 2-Photocurable EPDM slurry; 3-Axial lead screw; 4-Axial stepper motor; 5-Radial hydraulic extension rod; 6-Rotary motor; 7-Axial flange fixing plate; 8-Replaceable raw material pipe; 9-Pressure hose; 10-Extrusion screw; 11-Printing nozzle; 12-Ultraviolet light source; 13-Miniature camera. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0018] The purpose of this invention is to manufacture the internal heat insulation layer of an engine using 3D printing technology and a photothermal composite curing system. Specifically, a solid-state engine heat insulation layer integral 3D printing device and method based on a photothermal composite curing system is proposed for heat insulation layer manufacturing technology.

[0019] The present invention includes a photocurable EPDM slurry (1); an axial lead screw (2); an axial stepper motor (3); a radial hydraulic extension rod (4); a rotary motor (5); an axial flange fixing plate (6); a replaceable raw material pipe (7); a pressure hose (8); an extrusion screw (9); a printing nozzle (10); an ultraviolet light source (11); and a miniature camera (12).

[0020] The photocurable EPDM slurry is the primary printing material. The slurry can achieve rapid photocuring under ultraviolet or visible light irradiation, preventing the propellant from flowing or deforming during layered printing. This slurry is made by adding a small amount of photosensitive resin that can rapidly cure under ultraviolet light to conventional EPDM material, along with a photocuring diluent and a small amount of photoinitiator. After extrusion, the EPDM slurry can be rapidly cured by an ultraviolet light source integrated into the printhead, forming a hard surface shell. This is then followed by thermal vulcanization in a hot oven and compression molding for final shaping.

[0021] The lead screw, radial hydraulic extension rod, and axis flange fixing plate constitute its frame system, providing rigid support for the stepper motor and rotary motor. The lead screw is the frame on the engine's axis of symmetry, mainly used for positioning the axis and fixing the radial hydraulic extension rod; the radial hydraulic extension rod is used for radial positioning, fixed to the lead screw, and can be positioned by extending and shortening; the axis flange fixing plate is respectively installed on the front and rear end flange faces of the engine, used to fix the lead screw.

[0022] The axial stepper motor and rotary motor form its actuation system, working in conjunction with the frame to achieve precise positioning and movement of the print head. The axial stepper motor is mounted on the lead screw and is used to change the axial position of the radial hydraulic extension rod. The rotary motor is mounted on the axial flange mounting plate and is used to rotate the lead screw to change the angle of the radial hydraulic extension rod.

[0023] The replaceable material tube, pressure hose, extrusion screw, and print head constitute the material feeding system. The slurry is a viscous paste that needs to be extruded through a high-pressure gas outlet. The replaceable material tube serves as the slurry source and is designed to be replaceable; a new replaceable material tube is installed when it is no longer needed or when extrusion stops. The pressure hose is used to transport the slurry. The extrusion screw is a device that provides a stable output to the nozzle downstream of the replaceable material tube, and its speed can be adjusted by controlling the screw rotation. The print head is the outlet, and its outlet slurry diameter is adjustable, allowing for changes in print thickness based on printing accuracy requirements.

[0024] The ultraviolet light source is a light irradiation device integrated near the print head, which can output ultraviolet light of a certain wavelength and power to irradiate the printing area and cause the surface of the slurry to be initially solidified and shaped.

[0025] The miniature camera is an image recording device integrated near the print head, capable of recording images during the printing process to assess print quality in real time.

[0026] The device is installed as follows: (1) Connect the axial stepper motor to the axial flange fixing plate, connect the axial screw to the axial stepper motor, install the rotary motor on the axial screw, connect the radial hydraulic extension rod to the rotary motor, and the printing frame is installed; (2) Fix the 3D printing device printing frame on the engine housing with bolts to the flange; (3) Install the printing nozzle, ultraviolet light source and miniature camera in front of the extrusion screw, and install the above devices at the front end of the hydraulic extension rod; (4) Pour the photocurable EPDM slurry into the raw material pipe, and install the raw material pipe after the extrusion screw; (5) Connect the pressure hose to the raw material pipe and the air source, and the installation is completed; The printing method is as follows: A paste-like insulation slurry is pumped from a pressure hose to an extrusion screw. The extrusion screw, controlled by a motor, extrudes the slurry towards the print head at a set speed, completing the material extrusion. After extrusion, the material undergoes initial curing thanks to the ultraviolet light source above the print head and the photoinitiator in the printing material. During printing, a rotary motor controls the print head and radial hydraulic extension rod in the circumferential printing position, while the radial hydraulic extension rod controls the radial position of the print head. An axial stepper motor adjusts the axial position of the print head via a control axis screw, thus achieving precise control of the printing position. The print head rotates and advances from the front end cap to the rear end cap, printing a certain thickness of insulation layer at each location until printing is complete.

[0027] The design features of this invention are as follows: 1) This invention establishes a complete 3D printing molding process for a solid rocket engine insulation layer photo-thermal composite curing system, including photocurable EPDM slurry, lead screw, axial stepper motor, radial hydraulic extension rod, rotary motor, axial flange fixing plate, replaceable raw material pipe, pressure hose, extrusion screw, printing nozzle, ultraviolet light source and miniature camera. The molding process can realize the overall manufacturing of the insulation layer.

[0028] 2) This invention achieves accurate positioning and printing of 3D printing through a frame system, an actuation system and a raw material conveying system, and can print the insulation layer in layers and regions to achieve variable thickness molding of the insulation layer in the front and rear end caps.

[0029] 3) This invention utilizes a photo-thermal composite curing system of EPDM slurry and an ultraviolet light source to achieve preliminary curing during the printing process of the insulation layer. Through photopolymerization, the unsaturated double bonds in the slurry undergo cross-linking polymerization, forming a cured surface and thus initially shaping the printed area. The slurry, once cured, can be further layered and printed on top without collapsing, or it can adhere to the shell without changing shape due to gravity.

[0030] Example: like Figure 1 The diagram shown is a partial cross-sectional view of the method. The main components of this invention consist of an engine housing 1, a photocurable EPDM slurry 2, a frame system (axial lead screw 3, radial hydraulic extension rod 5, axial flange fixing plate 7), an actuation system (axial stepper motor 4, rotary motor 6), and a material feeding system (replaceable material pipe 8, pressure hose 9, extrusion screw 10, printing nozzle 11, ultraviolet light source 12, and miniature camera 13). The engine insulation layer is formed by 3D printing the slurry onto the surface of the engine housing.

[0031] Figure 2 The image shown is a printhead design diagram. Figure 1 Detailed diagram of the printing location.

[0032] like Figure 1 and Figure 2 As shown, the frame and actuation system control the printing position. A lead screw 3, controlling the axial position, is fixed inside the engine via an axial flange mounting plate 7. A rotary motor 6 is arranged on each side, controlling the circumferential position of the print head through rotation. An axial stepper motor 4 is mounted on the lead screw, controlling the axial position of the print head through axial movement along the lead screw. A radial hydraulic extension rod 5 controls the radial position of the print head through extension and retraction.

[0033] In the raw material conveying system, the photocurable EPDM slurry is stored in the replaceable raw material tube 8. High-pressure gas is delivered through a high-pressure gas source, which pumps the slurry in the replaceable raw material tube 8 to the outlet and extrudes it into the extrusion screw 10. The screw then evenly extrudes the slurry into the printing nozzle, which controls the diameter and speed of the printing slurry to form it on the engine housing.

[0034] During implementation, the device is first installed according to the following steps: (1) Connect the axial stepper motor to the axial flange fixing plate, connect the axial screw to the axial stepper motor, install the rotary motor on the axial screw, connect the radial hydraulic extension rod to the rotary motor, and the printing frame is installed; (2) Fix the 3D printing device printing frame on the engine housing with bolts to the flange; (3) Install the printing nozzle, ultraviolet light source and miniature camera in front of the extrusion screw, and install the above devices at the front end of the hydraulic extension rod; (4) Pour the photocurable EPDM slurry into the raw material pipe, and install the raw material pipe after the extrusion screw; (5) Connect the pressure hose to the raw material pipe and the air source, and the installation is completed; The printing process is as follows: A paste-like insulation slurry is pumped from a pressure hose to an extrusion screw. The extrusion screw, controlled by a motor, extrudes the slurry at a set speed towards the print head, completing the material extrusion. After extrusion, the material undergoes initial curing via the ultraviolet light source above the print head and the photoinitiator in the printing material. During printing, a rotary motor controls the print head and radial hydraulic extension rod in the circumferential printing position. The radial hydraulic extension rod controls the radial position of the print head, and an axial stepper motor adjusts the axial position of the print head via a control axis screw, thus achieving precise control of the printing position. The print head rotates and advances from the front end to the rear end, printing the engine insulation layer circumferentially layer by layer, ensuring a certain thickness of insulation layer is printed at each location. During printing, the slurry undergoes photocuring via the ultraviolet light source 12). After a single layer is printed, an additional thicker insulation layer can be designed and printed according to the insulation layer thickness, achieving complex insulation layer printing.

[0035] When one raw material tube 8 is used up, the raw material tube 8 can be replaced to achieve continuous printing.

[0036] A miniature camera 13 installed near the print head 11 can record the printed images in real time for analysis of print quality.

Claims

1. A 3D printing device for an integral solid engine insulation layer based on a photo-thermal composite curing system, characterized in that, It includes photocurable EPDM slurry, lead screw, axial stepper motor, radial hydraulic extension rod, rotary motor, axial flange fixing plate, replaceable raw material pipe, pressure hose, extrusion screw, printing nozzle, ultraviolet light source and miniature camera; After extrusion, the EPDM slurry is rapidly cured by an ultraviolet light source integrated into the print head to form a hard shell. It is then finally molded by hot vulcanization in a hot oven and pressing. The lead screw, radial hydraulic extension rod, and axial flange fixing plate constitute a frame system, providing rigid support for the axial stepper motor and rotary motor; the lead screw is the frame on the engine's axis of symmetry, used to position the axis and fix the radial hydraulic extension rod; the radial hydraulic extension rod is used for radial positioning, fixed on the lead screw, and can be positioned by extending and shortening; the axial flange fixing plates are respectively installed on the front and rear end flange faces of the engine, used to fix the lead screw; The axial stepper motor and the rotary motor constitute an actuation system, which works in conjunction with the frame system to achieve precise positioning and movement of the print head; the axial stepper motor is mounted on the lead screw and is used to change the axial position of the radial hydraulic extension rod; the rotary motor is mounted on the axial flange fixing plate and is used to rotate the lead screw to change the angle of the radial hydraulic extension rod. The replaceable raw material tube, pressure hose, extrusion screw, and printing nozzle constitute the raw material feeding system. The replaceable raw material tube is the slurry source and is designed to be replaceable, allowing replacement with a new replaceable raw material tube when it is no longer in use or when extrusion stops. The pressure hose is used to transport the slurry. The extrusion screw is a device that stably outputs slurry downstream of the replaceable raw material tube to the nozzle, and the slurry extrusion speed can be adjusted by controlling the screw speed. The printing nozzle is the discharge port, and the outlet slurry diameter is adjustable, allowing the printing output thickness to be changed according to the printing accuracy requirements. The ultraviolet light source is an illumination device integrated near the print head, which can output ultraviolet light of a certain wavelength and power to irradiate the printing area and cause the surface of the slurry to be initially solidified and shaped. The miniature camera is an image recording device integrated near the print head, capable of recording images during the printing process to assess print quality in real time.

2. The integral 3D printing device for a solid engine insulation layer based on a photo-thermal composite curing system according to claim 1, characterized in that, The photocurable EPDM slurry can achieve rapid photocuring under ultraviolet or visible light irradiation, preventing the propellant from flowing or deforming during layered printing.

3. The integral 3D printing device for a solid engine insulation layer based on a photo-thermal composite curing system according to claim 1, characterized in that, The photocurable EPDM slurry is made by adding a photosensitive resin that can be rapidly cured under ultraviolet light to EPDM material, and adding a photocurable diluent and a photoinitiator.

4. An installation method for the integral 3D printing device for the solid rocket motor insulation layer as described in claim 1, characterized in that, Includes the following steps: Step 1: Connect the axial stepper motor to the axial flange fixing plate, connect the axial lead screw to the axial stepper motor, install the rotary motor on the axial lead screw, connect the radial hydraulic extension rod to the rotary motor, and the printing frame is installed. Step 2: Secure the 3D printing frame to the engine housing using bolted flanges; Step 3: Install the print head, ultraviolet light source, and miniature camera before the extrusion screw, specifically at the front end of the hydraulic extension rod; Step 4: Pour the photocurable EPDM slurry into the raw material tube and install the raw material tube after the extrusion screw; Step 5: Connect the pressure hose to the raw material pipe and the air source. Installation is complete.

5. A printing method for a solid rocket motor insulation layer integral 3D printing device as described in claim 1, characterized in that, Includes the following steps: Step 1: Pump the paste-like insulation layer slurry from the pressure hose to the extrusion screw. The extrusion screw, controlled by the motor, extrudes the slurry to the print head at a set speed, thus completing the material extrusion. Step 2: After the material is extruded, it is initially cured by the ultraviolet light source above the print head and the photoinitiator in the printing material. Step 3: During printing, the rotary motor controls the print head and the radial hydraulic extension rod in the circumferential printing position, the radial hydraulic extension rod controls the radial position of the print head, and the axial stepper motor adjusts the axial position of the print head through the control axis screw, thereby achieving precise control of the printing position; Step 4: The print head rotates and advances from the front end cap to the rear end cap, printing a certain thickness of insulation layer at each location it passes through until printing is complete.

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