3D printing water-soluble mold for molding composite material

Abstract

The invention discloses a 3D printing water-soluble mold for molding a composite material. Comprising a 3D printing box room, and a metal core mold, a silicon rubber preset soft mold, a core shaft rotating mechanism, a multi-axial 3D printing tail end spraying and screening head, a spraying and screening flow speed controller, a graphic input and output control terminal, a fixed support, a boundary dimension online detection system and a water-soluble resin storage box which are located in the 3D printing box room; the two ends of the metal core mold are mounted on the fixed support through a core shaft rotating mechanism; and the silicon rubber preset soft mold is embedded into the water-soluble quartz sand mold. According to the invention, green, low-cost, high-quality, rapid and integrated manufacturing of a large closed-cavity complex composite material structure is realized, the manufacturing period of a mold used by the structure is greatly shortened, and the self weight and heating energy consumption of the mold are reduced; and a set of circulating low-cost, rapid and efficient manufacturing mode of assembling, printing, curing, monitoring, dissolving disassembly and recovery based on automatic control is innovatively formed.

Description

Technical Field

[0001] The invention belongs to the technical field of composite material structure molding technology, and in particular relates to a 3D printed water-soluble mold for composite material molding. Background Art

[0002] For the new generation of advanced aerospace equipment, reusable launch vehicles and other composite propellant tanks, water pressure-resistant load-bearing tubes, variable curvature inner skin reinforcement and other closed-cavity complex structures, since such structures require long-term high load-bearing, high-reliability and airtightness, the traditional manufacturing mode of punching and fastener connections between components cannot meet the current use conditions, making integral molding technology a must.

[0003] At present, in order to achieve smooth demoulding of closed cavity negative curvature narrow open space, composite integral molding molds mainly adopt a large number of block-type metal combination mold solutions. This solution has problems such as long design and manufacturing cycle, large processing volume, high cost, low efficiency of repeated assembly and disassembly, and frequent repair. Especially for large-scale aspect ratio composite structure products, the large deadweight of the metal mold requires the design of additional rigidity maintenance mechanism, which seriously affects the use turnover and heating rate of the mold during the molding process and increases energy consumption; in addition, when facing the internal protruding structure of the product, there are problems such as inadequate pressure transmission and inducing local defects. In summary, the shortcomings of existing mold design and manufacturing technology have led to low production efficiency and high cost of such composite products. Summary of the invention

[0004] The technology of the present invention solves the problem: Overcoming the shortcomings of the prior art, providing a 3D printed water-soluble mold for composite material molding, realizing green, low-cost, high-quality, rapid integrated manufacturing of large closed-cavity complex composite material structures, greatly shortening the manufacturing cycle of molds used for such structures, reducing the mold's own weight and heating energy consumption, and innovatively forming a set of "assembly-printing-curing-monitoring-dissolution-recycling" cyclic low-cost, rapid and efficient manufacturing mode based on automated control.

[0005] In order to solve the above technical problems, the present invention discloses a 3D printing water-soluble mold for composite material molding, comprising: a metal core mold, a silicone rubber pre-set soft mold, a core shaft rotation mechanism, a multi-axial 3D printing terminal spray screen head, a spray screen flow rate controller, a graphic input and output control terminal, a fixed support, an online detection system for external dimensions, a water-soluble resin storage tank and a 3D printing box room;

[0006] The metal core mold, water-soluble quartz sand mold, silicone rubber preset soft mold, mandrel rotation mechanism, multi-axial 3D printing end spray screen head, spray screen flow rate controller, graphic input and output control terminal, fixed support, external dimension online detection system and water-soluble resin storage tank are all set inside the 3D printing box room;

[0007] The fixed support is fixed at the bottom of the 3D printing box by mechanical connection; both ends of the metal core mold are installed on the fixed support through the core shaft rotating mechanism;

[0008] The water-soluble resin storage tank is connected to the multi-axial 3D printing terminal spray screen head through a pipeline and is suspended above the inside of the 3D printing box room; a spray screen flow rate controller is provided on the connecting pipeline between the water-soluble resin storage tank and the multi-axial 3D printing terminal spray screen head;

[0009] The online dimension detection system is fixed vertically on the mandrel rotating mechanism, and the real-time measured dimension data is fed back to the graphic input and output control terminal;

[0010] The graphic input and output control terminal is connected to the core shaft rotating mechanism, the multi-axial 3D printing end spray screen head, the spray screen flow rate controller and the shape dimension online detection system through wires;

[0011] The silicone rubber pre-set soft mold is embedded in the printed water-soluble quartz sand mold at the internal design position.

[0012] In the above-mentioned 3D printed water-soluble mold for composite material molding, the metal core mold and the core shaft rotation mechanism form a stable supporting mechanism through a fixed support when the mold is working; wherein, the metal core mold and the core shaft rotation mechanism are fixed or disassembled by mechanical connection, and the metal core mold relies on the rotation of the core shaft rotation mechanism to realize its own rotation at different speeds.

[0013] In the above-mentioned 3D printed water-soluble mold for composite material molding, the water-soluble quartz sand mold is sprayed and printed onto the metal core mold through the graphic input and output control terminal to control the core shaft rotation mechanism, the spray screen flow rate controller and the multi-axial 3D printing end spray screen head.

[0014] In the above-mentioned 3D printed water-soluble mold for composite material molding, the silicone rubber pre-set soft mold is embedded in the internal design position of the printed water-soluble quartz sand mold in the following manner: during the spray printing of the water-soluble quartz sand mold, the silicone rubber pre-set soft mold is first placed at the design position, and then the printing is continued to be completed, thereby realizing the inlay of the silicone rubber pre-set soft mold and the water-soluble quartz sand mold; or, after the spray printing of the water-soluble quartz sand mold is completed, a groove is cut at the design position and the silicone rubber pre-set soft mold is embedded.

[0015] In the above-mentioned 3D printed water-soluble mold for composite material molding, the metal core mold includes: a high-rigidity metal core shaft and a flexible connecting rod mechanism; wherein the high-rigidity metal core shaft and the flexible connecting rod mechanism are connected by a detachable and assembled pin-type mechanical connection.

[0016] In the above-mentioned 3D printed water-soluble mold for composite material molding, the pin installation position of the flexible linkage mechanism on the high-rigidity metal core shaft, the vertical axial length of the flexible linkage mechanism itself, and the number of flexible linkage mechanisms are determined according to the external dimensions of the product to be produced.

[0017] In the above-mentioned 3D printed water-soluble mold for composite material molding, the multi-axial 3D printed terminal spray screen head includes: a water-soluble resin spray device and a quartz sand mesh screen; wherein the water-soluble resin spray device is located above the quartz sand mesh screen, and the water-soluble resin in the water-soluble resin storage tank is evenly mixed with the quartz sand screened through the quartz sand mesh screen after passing through the water-soluble resin spray device and sprayed.

[0018] In the above-mentioned 3D printed water-soluble mold for composite material molding, the water-soluble resin spraying device includes: a vacuum system, a heating system and a pressurizing system; wherein the vacuum system, the heating system and the pressurizing system are independently installed in the 3D printing box room; the working sequence of the water-soluble resin spraying device is as follows: first turn on the vacuum system to vacuum the inside of the water-soluble resin spraying device; after the vacuum degree reaches the requirement, turn on the heating system to heat the water-soluble resin; after the water-soluble resin reaches the temperature requirement, turn on the pressurizing system to adjust the pressure for spraying.

[0019] The above-mentioned 3D printed water-soluble mold for composite material molding also includes: a display and control console; wherein the display and control console is embedded and installed on the shell of the 3D printing box room, and is used to realize the integrated display and control of the spray screen flow rate controller, the graphic input and output control terminal, the online detection system of the external dimensions, the vacuum system, the heating system and the pressurization system.

[0020] In the above-mentioned 3D printed water-soluble mold for composite material molding, the printing process of the 3D printed water-soluble mold for composite material molding is as follows:

[0021] Place the high-rigidity metal mandrel horizontally, and install and connect both ends of the high-rigidity metal mandrel to the mandrel rotating mechanism;

[0022] The fixed support is adjusted, placed and fixedly installed on the core shaft rotating mechanism according to the length of the high-rigidity metal core shaft;

[0023] A flexible link mechanism is connected to a high-rigidity metal core shaft according to a radial section, and the overall external dimensions of the metal core mold are adjusted through the flexible link mechanism of each unit area;

[0024] Install a silicone rubber pre-set soft mold on the outer surface of the metal core mold;

[0025] Put the water-soluble resin into the water-soluble resin storage tank, and use the vacuum system of the water-soluble resin spraying device to vacuum defoam the water-soluble resin throughout the process, and control the vacuum degree at ≤-100kPa; turn on the heating system of the water-soluble resin spraying device to heat the temperature of the water-soluble resin from room temperature to 40±3℃, ensuring that the viscosity of the water-soluble resin before spraying is ≤100mPa·s; then turn on the pressurization system of the water-soluble resin spraying device to ensure that the pressure before spraying is controlled at 0.1±0.01MPa. At this point, all states before the water-soluble resin spraying are ready;

[0026] The quartz sand with a particle size of 50um was soaked in an epoxy sizing agent emulsion with a solid content of 50% for 30 minutes, then cured in an oven at 100°C for 60 minutes for drying, and finally sieved with a quartz sand mesh with a mesh size of 300 to ensure that the particle size of the quartz sand does not exceed 50um. The quartz sand mesh was lubricated with polytetrafluoroethylene to ensure that the quartz sand flowed smoothly, evenly and continuously through the sieve. At this point, all states of the quartz sand before 3D printing were ready;

[0027] Upload the digital model of the water-soluble quartz sand mold to be 3D printed to the graphic input and output control terminal;

[0028] The multi-axial 3D printing end spray screen head is controlled by the spray screen flow rate controller to start printing the water-soluble quartz sand mold;

[0029] The online dimension detection system is used to monitor the dimension accuracy in real time during the printing process to ensure that the 3D printed graphics are consistent with the actual object;

[0030] After printing is completed, the appearance and internal quality inspection are carried out.

[0031] The present invention has the following advantages:

[0032] (1) The present invention discloses a 3D printed water-soluble mold for composite material molding. Compared with the traditional block-type metal combination mold solution, the mold design and manufacturing cycle is greatly shortened, the processing volume is reduced, and the production and assembly costs are reduced. It also solves the long-standing problems of low production efficiency caused by the short service life, high maintenance cost, and repeated assembly and disassembly of metal combination molds.

[0033] (2) The present invention discloses a 3D printed water-soluble mold for composite material molding. Compared with the traditional block-type metal combination mold solution, a combination solution of a metal core mold and a 3D printed water-soluble quartz sand mold is proposed, which achieves effective weight reduction of large aspect ratio molds, improves the dimensional accuracy of the composite material products, and at the same time reduces the overall mold size, improves thermal efficiency, greatly reduces energy consumption, and realizes green, low-cost, high-precision and rapid manufacturing of molds.

[0034] (3) The present invention discloses a 3D printed water-soluble mold for composite material molding, and proposes a silicone rubber pre-set soft mold that is flexibly matched with a metal core mold and a 3D printed water-soluble quartz sand mold pre-embedded solution, which breaks through the bottleneck problem of the protruding structure inside the closed cavity of the composite material that the pressurized pressure is not transmitted in place and induces local defects.

[0035] (4) The present invention discloses a 3D printed water-soluble mold for composite material molding. Compared with the traditional block-type metal combination mold solution, a technical approach for net-size 3D printed water-soluble quartz sand mold is proposed, which realizes the repeated recycling of quartz sand through hydrolysis reaction, and realizes the green and recyclable manufacturing of large closed-cavity negative curvature narrow open space molds from the process design.

[0036] (5) The present invention discloses a 3D printed water-soluble mold for composite material molding, which is suitable for the processing and manufacturing of closed-cavity complex structures in the fields of aerospace and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a structural schematic diagram of a 3D printed water-soluble mold for composite material molding in an embodiment of the present invention. DETAILED DESCRIPTION

[0038] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments disclosed in the present invention will be further described in detail below with reference to the accompanying drawings.

[0039] One of the core ideas of the present invention is: a 3D printed water-soluble mold for composite material molding is disclosed. The specific principle is to use 3D printing technology to atomize and spray a water-soluble, low-viscosity, room-temperature curing resin onto quartz sand with uniform particle size, and evenly shape it into a set projection pattern on a two-dimensional plane, thereby realizing the net size additive manufacturing of a water-soluble resin quartz sand composite mold. After the composite material product is cured, the viscosity reduction principle of the water-soluble resin hydrolysis reaction is utilized to inject water into the mold to achieve the function of rapid demolding.

[0040] Reference Figure 1In this embodiment, the 3D printing water-soluble mold for composite material molding includes: a metal core mold 1, a silicone rubber pre-set soft mold 5, a mandrel rotating mechanism 6, a multi-axial 3D printing terminal spray screen head 7, a spray screen flow rate controller 10, a graphic input and output control terminal 11, a fixed support 12, an online detection system for external dimensions 13, a water-soluble resin storage tank 14 and a 3D printing box 15. Among them, the metal core mold 1, the water-soluble quartz sand mold 4, the silicone rubber pre-set soft mold 5, the mandrel rotating mechanism 6, the multi-axial 3D printing terminal spray screen head 7, the spray screen flow rate controller 10, the graphic input and output control terminal 11, the fixed support 12, the online detection system for external dimensions 13 and the water-soluble resin storage tank 14 are all arranged inside the 3D printing box 15. The fixed support 12 is fixed to the lower part of the 3D printing box 15 by mechanical connection; the two ends of the metal core mold 1 are installed on the fixed support 12 through the mandrel rotating mechanism 6. The water-soluble resin storage tank 14 is connected to the multi-axial 3D printing terminal spray screen head 7 through a pipeline and is suspended above the inside of the 3D printing box room 15; a spray screen flow rate controller 10 is provided on the connecting pipeline between the water-soluble resin storage tank 14 and the multi-axial 3D printing terminal spray screen head 7. The online detection system 13 of the external dimensions is vertically fixed on the mandrel rotating mechanism 6, and the real-time measured external dimensions data is fed back to the graphic input and output control terminal 11. The graphic input and output control terminal 11 is connected to the mandrel rotating mechanism 6, the multi-axial 3D printing terminal spray screen head 7, the spray screen flow rate controller 10 and the online detection system 13 of the external dimensions through wires. The silicone rubber pre-set soft mold 5 is embedded in the internal design position of the printed water-soluble quartz sand mold 4.

[0041] In this embodiment, the metal core mold 1 and the core shaft rotating mechanism 6 form a stable supporting mechanism when the mold is working through the fixed support 12. The metal core mold 1 and the core shaft rotating mechanism 6 are fixed or disassembled by mechanical connection, and the metal core mold 1 relies on the rotation of the core shaft rotating mechanism 6 to realize its own rotation at different speeds.

[0042] In this embodiment, the water-soluble quartz sand mold 4 controls the core shaft rotation mechanism 6, the spray screen flow rate controller 10 and the multi-axial 3D printing end spray screen head 7 to spray and print onto the metal core mold 1 through the graphic input and output control terminal 11.

[0043] In this embodiment, the silicone rubber pre-set soft mold 5 is in an inlay relationship with the water-soluble quartz sand mold 4. Specifically, the silicone rubber pre-set soft mold 5 can be embedded in the internal design position of the printed water-soluble quartz sand mold 4 in the following manner: during the spray printing process of the water-soluble quartz sand mold 4, the silicone rubber pre-set soft mold 5 is first placed at the design position, and then the printing is continued to be completed, thereby achieving the inlay of the silicone rubber pre-set soft mold 5 and the water-soluble quartz sand mold 4. Or, after the spray printing of the water-soluble quartz sand mold 4 is completed, a groove is cut at the design position and the silicone rubber pre-set soft mold 5 is inlaid.

[0044] In this embodiment, the metal core mold 1 mainly includes: a high-rigidity metal core shaft 2 and a flexible link mechanism 3. Among them, the high-rigidity metal core shaft 2 and the flexible link mechanism 3 are connected by a detachable and assembled pin-type mechanical connection. According to the external dimensions of the product to be produced, the pin installation position of the flexible link mechanism 3 on the high-rigidity metal core shaft 2, the vertical axial length of the flexible link mechanism 3 itself, and the number of the flexible link mechanisms 3 are dynamically adjusted, and the function of flexible and adjustable settings is provided.

[0045] In this embodiment, the multi-axial 3D printing terminal spray head 7 mainly includes: a water-soluble resin spray device 8 and a quartz sand mesh screen 9. The water-soluble resin spray device 8 is located above the quartz sand mesh screen 9. The water-soluble resin in the water-soluble resin storage tank 14 is evenly mixed with the quartz sand screened by the quartz sand mesh screen 9 after passing through the water-soluble resin spray device 8 and then sprayed. The flow rate of the sprayed mixed medium can be controlled by the water-soluble resin spray device 8, and the particle size and flow rate of the quartz sand can be controlled by the quartz sand mesh screen 9, so as to always maintain a stable sprayed mixing ratio.

[0046] In this embodiment, the water-soluble resin spraying device 8 mainly includes: a vacuum system 16, a heating system 17 and a pressurizing system 18. Among them, the vacuum system 16, the heating system 17 and the pressurizing system 18 are independently installed in the 3D printing chamber 15. The working sequence of the water-soluble resin spraying device 8 is as follows: first, the vacuum system 16 is turned on to vacuum the inside of the water-soluble resin spraying device 8; after the vacuum degree reaches the requirement, the heating system 17 is turned on to heat the water-soluble resin; after the water-soluble resin reaches the temperature requirement, the pressurizing system 18 is turned on to adjust the pressure for spraying.

[0047] In this embodiment, the 3D printed water-soluble mold for composite material molding may further include: a display control console 19. The display control console 19 is embedded and installed on the shell of the 3D printing box 15, and is used to realize the integrated display and control of the spray screen flow rate controller 10, the graphic input and output control terminal 11, the online detection system of the external dimensions 13, the vacuum system 16, the heating system 17 and the pressurization system 18.

[0048] In this embodiment, the printing process of the 3D printed water-soluble mold for composite material molding is as follows:

[0049] Step 1: Place the high-rigidity metal core shaft 2 horizontally, and install and connect both ends of the high-rigidity metal core shaft 2 to the core shaft rotating mechanism 6.

[0050] Step 2: Adjust, place and fix the fixed support 12 on the core shaft rotating mechanism 6 according to the length of the high-rigidity metal core shaft 2 .

[0051] Step 3, connecting the flexible link mechanism 3 to the high-rigidity metal core shaft 2 according to the radial section, and adjusting the overall external dimensions of the metal core mold 1 through the flexible link mechanism 3 of each unit area.

[0052] Step 4: Install the silicone rubber pre-set soft mold 5 on the outer surface of the metal core mold 1.

[0053] Step 5, put the water-soluble resin into the water-soluble resin storage tank 14, and use the vacuum system 16 of the water-soluble resin spraying device 8 to vacuum defoam the water-soluble resin throughout the process, and control the vacuum degree at ≤-100kPa; turn on the heating system 17 of the water-soluble resin spraying device 8, and heat the temperature of the water-soluble resin from room temperature to 40±3°C to ensure that the viscosity of the water-soluble resin before spraying is ≤100mPa·s; then turn on the pressurizing system 18 of the water-soluble resin spraying device 8 to ensure that the pressure before spraying is controlled at 0.1±0.01MPa. At this point, all states before the water-soluble resin spraying are ready.

[0054] Step 6, soak the quartz sand with a particle size of 50um in an epoxy sizing agent emulsion with a solid content of 50% for 30 minutes, then cure and dry in an oven at 100°C for 60 minutes, and finally sieve with a 300-mesh quartz sand screen 9 to ensure that the particle size of the quartz sand does not exceed 50um. The quartz sand screen 9 is surface lubricated with polytetrafluoroethylene to ensure that the quartz sand flows smoothly, evenly and continuously through the sieve. At this point, all states of the quartz sand before 3D printing are ready.

[0055] Step 7, uploading the digital model of the water-soluble quartz sand mold 4 to be 3D printed to the graphic input and output control terminal 11.

[0056] Step 8, control the multi-axial 3D printing end spray head 7 through the spray flow rate controller 10 to start printing the water-soluble quartz sand mold 4.

[0057] Step 9, using the online dimension detection system 13 to monitor the dimensional accuracy during the printing process in real time to ensure that the 3D printed graphics are consistent with the actual object.

[0058] Step 10: After printing is completed, perform appearance and internal quality inspection.

[0059] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

[0060] The contents not described in detail in the specification of the present invention belong to the common knowledge of the professionals in this field.

Claims

1. A 3D printed water-soluble mold for composite material molding, characterized in that: include: A metal core mold (1), a silicone rubber pre-set soft mold (5), a core shaft rotating mechanism (6), a multi-axial 3D printing end spray screen head (7), a spray screen flow rate controller (10), a graphic input and output control terminal (11), a fixed support (12), an online detection system for external dimensions (13), a water-soluble resin storage tank (14) and a 3D printing chamber (15); The metal core mold (1), the water-soluble quartz sand mold (4), the silicone rubber pre-set soft mold (5), the core shaft rotating mechanism (6), the multi-axial 3D printing end spray screen head (7), the spray screen flow rate controller (10), the graphic input and output control terminal (11), the fixed support (12), the external dimension online detection system (13) and the water-soluble resin storage tank (14) are all arranged inside the 3D printing box room (15); The fixed support (12) is fixed at the lower part of the interior of the 3D printing chamber (15) by mechanical connection; both ends of the metal core mold (1) are mounted on the fixed support (12) through a core shaft rotating mechanism (6); The water-soluble resin storage tank (14) is connected to the multi-axial 3D printing terminal spray screen head (7) through a pipeline and is suspended above the interior of the 3D printing chamber (15); a spray screen flow rate controller (10) is provided on the connecting pipeline between the water-soluble resin storage tank (14) and the multi-axial 3D printing terminal spray screen head (7); The online dimension detection system (13) is vertically fixed on the core shaft rotating mechanism (6) and feeds back the dimension data measured in real time to the graphic input and output control terminal (11); The graphic input and output control terminal (11) is respectively connected to the core shaft rotating mechanism (6), the multi-axial 3D printing end spray screen head (7), the spray screen flow rate controller (10) and the external dimension online detection system (13) through wires; The silicone rubber pre-set soft mold (5) is embedded in the internal design position of the printed water-soluble quartz sand mold (4).

2. The 3D printed water-soluble mold for composite material molding according to claim 1, characterized in that: The metal core mold (1) and the core shaft rotating mechanism (6) form a stable supporting mechanism when the mold is working through a fixed support (12); wherein the metal core mold (1) and the core shaft rotating mechanism (6) are fixed or disassembled through a mechanical connection, and the metal core mold (1) relies on the rotation of the core shaft rotating mechanism (6) to achieve its own rotation at different speeds.

3. The 3D printed water-soluble mold for composite material molding according to claim 1, characterized in that: The water-soluble quartz sand mold (4) is spray-printed onto the metal core mold (1) through a graphic input and output control terminal (11) to control a core shaft rotation mechanism (6), a spray screen flow rate controller (10) and a multi-axial 3D printing terminal spray screen head (7).

4. The 3D printed water-soluble mold for composite material molding according to claim 3, characterized in that: The silicone rubber pre-set soft mold (5) is embedded in the designed position inside the water-soluble quartz sand mold (4) obtained by printing in the following manner: during the spray printing process of the water-soluble quartz sand mold (4), the silicone rubber pre-set soft mold (5) is first placed at the designed position, and then the printing is continued to be completed, thereby achieving the embedding of the silicone rubber pre-set soft mold (5) and the water-soluble quartz sand mold (4); or, after the spray printing of the water-soluble quartz sand mold (4) is completed, a groove is cut at the designed position and the silicone rubber pre-set soft mold (5) is embedded and installed.

5. The 3D printed water-soluble mold for composite material molding according to claim 1, characterized in that: The metal core mold (1) comprises: a high-rigidity metal core shaft (2) and a flexible connecting rod mechanism (3); wherein the high-rigidity metal core shaft (2) and the flexible connecting rod mechanism (3) are connected by a detachable and assembled pin-type mechanical connection.

6. The 3D printed water-soluble mold for composite material molding according to claim 5, characterized in that: The pin installation position of the flexible link mechanism (3) on the high-rigidity metal core shaft (2), the vertical axial length of the flexible link mechanism (3) itself, and the number of flexible link mechanisms (3) are determined according to the external dimensions of the product to be produced.

7. The 3D printed water-soluble mold for composite material molding according to claim 5, characterized in that: A multi-axial 3D printing terminal spray screen head (7) comprises: a water-soluble resin spray device (8) and a quartz sand mesh screen (9); wherein the water-soluble resin spray device (8) is located above the quartz sand mesh screen (9); the water-soluble resin in the water-soluble resin storage tank (14) is evenly mixed with the quartz sand screened by the quartz sand mesh screen (9) after passing through the water-soluble resin spray device (8) and then sprayed.

8. The 3D printed water-soluble mold for composite material molding according to claim 7, characterized in that: The water-soluble resin spraying device (8) comprises: a vacuum system (16), a heating system (17) and a pressurizing system (18); wherein the vacuum system (16), the heating system (17) and the pressurizing system (18) are independently installed in a 3D printing chamber (15); the working sequence of the water-soluble resin spraying device (8) is as follows: firstly, the vacuum system (16) is turned on to vacuum the inside of the water-soluble resin spraying device (8); after the vacuum degree reaches the required level, the heating system (17) is turned on to heat the water-soluble resin; after the water-soluble resin reaches the required temperature, the pressurizing system (18) is turned on to adjust the pressure for spraying.

9. The 3D printed water-soluble mold for composite material molding according to claim 8, characterized in that: Also includes: A display and control console (19); wherein the display and control console (19) is embedded and installed on the shell of the 3D printing box (15), and is used to realize the integrated display and control of the spray screen flow rate controller (10), the graphic input and output control terminal (11), the external dimension online detection system (13), the vacuum system (16), the heating system (17) and the pressurization system (18).

10. The 3D printed water-soluble mold for composite material molding according to claim 8, characterized in that: The printing process of the 3D printed water-soluble mold for composite material molding is as follows: Placing the high-rigidity metal core shaft (2) horizontally, and installing and connecting both ends of the high-rigidity metal core shaft (2) to the core shaft rotating mechanism (6); The fixed support (12) is adjusted, placed, and fixedly installed on the core shaft rotating mechanism (6) according to the length of the high-rigidity metal core shaft (2); A flexible link mechanism (3) is connected to a high-rigidity metal core shaft (2) according to a radial section, and the overall external dimensions of the metal core mold (1) are adjusted through the flexible link mechanism (3) of each unit area; A silicone rubber pre-set soft mold (5) is installed on the outer surface of the metal core mold (1); The water-soluble resin is placed in a water-soluble resin storage tank (14), and the vacuum system (16) of the water-soluble resin spraying device (8) is used to perform vacuum defoaming on the water-soluble resin throughout the process, and the vacuum degree is controlled at ≤-100 kPa; the heating system (17) of the water-soluble resin spraying device (8) is turned on to heat the temperature of the water-soluble resin from room temperature to 40±3° C., ensuring that the viscosity of the water-soluble resin before spraying is ≤100 mPa·s; then the pressurizing system (18) of the water-soluble resin spraying device (8) is turned on to ensure that the pressure before spraying is controlled at 0.1±0.01 MPa, and all states before spraying the water-soluble resin are ready; Quartz sand with a particle size of 50 μm is soaked in an epoxy sizing agent emulsion with a solid content of 50% for 30 minutes, then cured in an oven at 100° C. for 60 minutes and dried, and finally sieved with a 300-mesh quartz sand sieve (9) to ensure that the particle size of the quartz sand does not exceed 50 μm. The quartz sand sieve (9) is lubricated with polytetrafluoroethylene to ensure that the quartz sand flows smoothly, evenly and continuously through the sieve. At this point, all states of the quartz sand before 3D printing are ready; Uploading the digital model of the water-soluble quartz sand mold (4) to be 3D printed to the graphic input and output control terminal (11); The multi-axial 3D printing end spraying and screening head (7) is controlled by a spraying and screening flow rate controller (10) to start printing the water-soluble quartz sand mold (4); An online dimension detection system (13) is used to monitor the dimension accuracy in real time during the printing process to ensure that the 3D printed graphics are consistent with the actual object; After printing is completed, the appearance and internal quality inspection are carried out.

Images