Precision Forming Method and Device for Multi-Material and Multi-Process Collaborative Additive Manufacturing

Abstract

The present invention discloses a precise forming method and device for multi-material and multi-process collaborative additive manufacturing. The device is composed of a sand suction and feeding collaborative mechanism, an inkjet printing mechanism, a feeding and compaction mechanism, a heating and bonding curing mechanism, a printing platform and a main body frame. The sand suction and feeding collaborative mechanism can achieve fixed-point precise sand suction and sand dropping according to the slicing information. The inkjet printing mechanism can spray resin and curing agent in the printing area according to the slicing. The feeding and compaction mechanism can achieve the feeding of molding sand and improve the density of the sand mold. The heating and bonding curing mechanism can accelerate the rapid curing between the molding sand particles. Through high-flexibility fixed-point sand laying, rapid curing of single-layer molding sand, and rolling compaction, the overall rapid, high-precision and high-efficiency forming of multi-material sand molds can be realized, providing a reference for the high-flexibility forming of multi-material sand molds, filling the deficiencies of multi-material printing in the field of sand mold printing, and accelerating the development of sand mold printing towards the direction of multi-material and multi-process collaborative additive manufacturing.

Description

Technical Field

[0001] The present invention belongs to the field of sand mold 3D printing, and relates to the field of multi-material sand mold 3D printing, and in particular to a multi-material and multi-process collaborative additive manufacturing precision forming method and device. Background Art

[0002] With the increasing output of complex castings in sand casting, the demand for high-quality and high-performance castings in complex environments is also increasing. Sand casting is a commonly used metal casting process, which is widely used due to its simplicity, flexibility and economy. With the continuous development of science and technology, sand casting has made great progress in material properties, equipment control technology and production process.

[0003] The development of sand casting technology has driven the development of castings towards complexity and high performance. Faced with complex curved thin-walled castings, sand casting currently uses a variety of materials to manufacture sand molds. At present, multi-material sand casting involves printing or cutting a single material sand, and then assembling such sand molds for pouring. This type of multi-material composite sand mold does not involve the field of multi-material overall or integrated printing, and the multi-material composite sand mold produced has poor manufacturing flexibility. Patent application number "CN202210548767.2" is a highly flexible multi-region sand-laying method and device for multi-material sand mold printing. The patent processes the sand-laying area into a grid, and uses multi-grid sanding and vibration to achieve grid area sand-laying, but the sand-laying movement flexibility is not high, and the amount of sand falling during vibration is uncontrollable. Faced with increasingly complex castings, it is necessary to control the quality of the castings while ensuring efficient and high-precision forming of the castings. At present, it is difficult to coordinate the control of multi-material and multi-process sand laying. The use of vibration fine sand laying requires preventing the sand from arching in the sand vibration tube and the sand suction structure from absorbing sand at a fixed point and in a fixed quantity without damaging the printed sand mold. Research on multi-material sand mold printing needs to further realize highly flexible sand laying printing and precise sand laying of multiple material sands. Summary of the invention

[0004] In order to solve the above problems, the present invention discloses a multi-material and multi-process collaborative additive manufacturing precision forming method and device, which realizes integrated forming by sucking and dropping sand and heating and compacting specific areas of the slices. Each layer can realize multi-material molding sand laying according to the slice information, thereby realizing the overall forming of multi-material sand mold printing.

[0005] A precise forming device for multi-material and multi-process collaborative additive manufacturing, which is composed of an integrated sand suction and sand feeding mechanism, an inkjet printing mechanism, a feeding and compaction mechanism, a heating and bonding curing mechanism, a printing platform and a main frame. The integrated sand suction and sand feeding mechanism consists of a sand suction device, a negative pressure pipe, a first blanking box, a second blanking box, a screen, a transducer, a material box support frame, a shock absorber, module two and a drag chain. One end of the negative pressure pipe is connected to the sand suction device, and the other end is externally connected to a negative pressure device. The first blanking box and the second blanking box are fixed on the material box support frame. The shock absorber is fixed between the material box support frame and module two. The drag chain is fixed on module two. The first blanking box and the second blanking box are externally connected to the transducer and are equipped with a screen inside. The transducer is externally connected to an ultrasonic generator. Module two is fixedly installed on the slider table. The inkjet printing mechanism consists of module three, a curing agent spraying mechanism and a resin spraying mechanism. The curing agent spraying mechanism and the resin spraying mechanism are fixedly installed on module three. Module three is fixedly installed on the slider table. The feeding and compaction mechanism consists of a feeding device, a compaction roller mechanism and a roller support frame. The feeding device is fixed on the bottom plate of the device support frame. The roller is fixedly installed on the roller support frame. The roller support frame is fixedly installed on the slider table. The heating and bonding curing mechanism consists of a heating pipe and a heating pipe cover. The heating pipe is fixed in the heating pipe cover. The heating pipe cover is fixedly installed on the slider table. The main frame consists of a device support frame, module one and a slider table. The slider table is fixedly installed on module one. Module one is fixedly installed on the device support frame.

[0006] Further, the first blanking box and the second blanking box are composed of upper and lower parts. The upper part is a cylinder, which is mainly used to store the standby molding sand. At the same time, the screen is located in the middle of the upper and lower parts. The lower part consists of two conical mechanisms. The upper conical mechanism guides the vibrated and falling molding sand flow to the lower conical mechanism. There is a screen between the upper and lower conical mechanisms. The screen is mainly used to break the arching problem of the molding sand at the cone mouth in the upper cone. At the same time, when vibrating, the molding sand falls more scattered and is not easy to block the lower cone. There is a processing groove at the contact between the lower cone one and the upper cone one to prevent the screen from being too small to vibrate. The smaller lower cone mouth is conducive to accurate fixed-point sand spreading. The whole blanking box mainly realizes the falling of the molding sand and controls the sand falling amount through ultrasonic or mechanical structure vibration. The sand suction device consists of three parts: a cylinder sleeve, an upper cone two, and a piston movement lower cone. The cylinder sleeve provides a sealed environment and supports the upper cone collecting the piston movement lower cone. The upper cone two is used to better collect the sucked sand to the negative pressure pipe orifice and discharge the molding sand particles. The piston movement lower cone is divided into a lower cone two and a piston cylinder sleeve. The lower cone two moves up and down on the piston cylinder sleeve, and it is mainly used for accurate fixed-point sand suction.

[0007] Furthermore, the curing agent spraying mechanism and the resin spraying mechanism are each on one side of Module 3, the first feeding box, the second feeding box, and the sand suction device are each on one side of Module 2, the compaction roller and the heating and bonding curing mechanism are located between Module 1 and Module 2, the roller is close to Module 2, and the heating and bonding curing mechanism is close to Module 1. The distance between the resin nozzle in the resin spraying mechanism and the curing agent nozzle in the curing agent spraying mechanism needs to be an integer multiple of the width.

[0008] A precise forming method for multi-material and multi-process collaborative additive manufacturing, the steps of which are as follows:

[0009] (1) Divide the printed sand mold three-dimensional model into multiple groups of models according to the casting performance requirements of the casting and perform grouped slicing on the models. At the same time, the feeding device performs sand feeding. Module 1 drives the slider table to move multiple widths. When the roller rolls over the feeding device, the molding sand is rolled and spread on the printing platform. Module 2 drives the curing agent spraying mechanism and the resin spraying mechanism to move. The curing agent spraying mechanism and the resin spraying mechanism spray resin and curing agent according to one group in the divided models. After one layer of printing is completed, infrared heating is performed during its return journey. At this time, the molding sand particles need to reach a cured state and not be sucked away.

[0010] (2) Module 1 drives the slider table to move in width. The sand suction device precisely sucks sand according to the second group of sliced areas in the divided models. When the sand suction device reaches the sliced area, the lower cone descends a certain distance in the piston cylinder sleeve. After sand suction is completed, the lower cone rises a certain distance to complete the sand suction procedure. At the same time, according to this sliced information, the first feeding box drops chromite sand, fine silica sand, zircon sand, etc. of the molding sand in the sand suction area through ultrasonic or mechanical vibration. Then Module 2 drives the curing agent spraying mechanism and the resin spraying mechanism to spray resin and curing agent according to this sliced information. After one layer of printing is completed, infrared heating is performed during its return journey.

[0011] (3) Perform the operations in step (2) until the single-layer multi-material sand mold printing is completed, and repeat the above steps until the overall sand mold printing is completed.

[0012] Furthermore, the multi-material sand mold three-dimensional model is divided according to the casting performance of the casting. The molding sand used in the feeding device is coarse silica sand, and the molding sand dropped by the first feeding box or the second feeding box is chromite sand, fine silica sand, zircon sand, etc.

[0013] Furthermore, the temperature of the heating tube is between 200°C and 300°C, the radiation frequency is 10 - 100 HZ. At the same time, the heating temperature is feedback-regulated according to the return moving speed. At the same time, the temperature of the heating tube needs to ensure that the molding sand that can spray resin and curing agent can quickly undergo an adhesive reaction to achieve curing between the molding sand particles; heat and cure the molding sand particles to make them solidify rapidly, and the non-solidified molding sand can be sucked away by the sand suction device.

[0014] Further, when the curing agent spraying mechanism reaches above the printing platform, it performs a width movement. The width movement length is the width of the printing nozzle, and it is required that the length of the nozzle in the curing agent spraying mechanism is equal to the length of the nozzle in the resin spraying mechanism. The length of the printing area is an integer multiple of the width movement length.

[0015] Further, when the sand suction device reaches within the width of the sand suction area in the slice, it starts to perform a stage movement to the first blanking box or the second blanking box to complete the width of the sand falling area. The stage movement length is the diameter of the lower conical opening in the sand suction device, and the width movement length is an integer multiple of the stage movement length. The diameter of the lower conical opening in the sand suction device is equal to the diameter of the lower conical openings of the first blanking box and the second blanking box. At the same time, the control of the stage movement takes precedence over the width movement, and the stage movement must cover the entire width movement length. The reason for this design is that the sand suction device, the sand falling device, and the inkjet system are fixed in a set of motion systems. The inkjet system can only print with a fixed width each time. Therefore, the width movement distance is an integer multiple of the stage movement of the sand suction device and the sand falling device. Because the stage movement distance is short, the control of the stage movement takes precedence over the width movement.

[0016] After adopting the above technical solutions, the beneficial effects of the present invention are as follows:

[0017] 1. By using the sand suction device and the blanking device to perform sand suction and sand falling according to the slice information, multi-material molding sand can be accurately laid at fixed points, and then multi-material molding sand can be laid layer by layer, improving the flexibility and accuracy of sand laying;

[0018] 2. Using rollers to roll and heating tubes for heating can improve the density of each layer of molding sand and achieve rapid bonding and curing between molding sand particles. During the sand suction process, the molding sand in the printed area will not be sucked away, improving the accuracy of sand laying;

[0019] 3. By using the resin spraying mechanism and the curing agent spraying mechanism to spray resin and curing agent on the printing area according to the slice information, the molding sand in the unprinted area can be recycled, saving the amount of molding sand and curing agent used;

[0020] 4. Through high-flexibility fixed-point sand laying, rapid curing of single-layer molding sand, and rolling compaction, the overall rapid, high-precision, and efficient forming of multi-material sand molds can be achieved, providing a reference for the high-flexibility forming of multi-material sand molds, filling the gaps in multi-material printing in the field of sand mold printing, and accelerating the development of sand mold printing in the multi-material direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is the overall drawing of the precise forming device for multi-material and multi-process collaborative additive manufacturing;

[0022] Figure 2 It is the top view of the precise forming device for multi-material and multi-process collaborative additive manufacturing;

[0023] Figure 3 Screenshot at B-B of the precise forming device for multi-material and multi-process collaborative additive manufacturing

[0024] Figure 4 Screenshot of the vibrating sand falling mechanism of the precise forming device for multi-material and multi-process collaborative additive manufacturing

[0025] Figure 5 Screenshot of the sand suction mechanism of the precise forming device for multi-material and multi-process collaborative additive manufacturing

[0026] Figure 6 Schematic diagram of the precise forming method for multi-material and multi-process collaborative additive manufacturing

[0027] Figure 7 Single-layer printing flow chart of the precise forming method for multi-material and multi-process collaborative additive manufacturing

[0028] Figure 8 Schematic diagram of the moving length in the precise forming method for multi-material and multi-process collaborative additive manufacturing

[0029] Figure 9 Schematic diagram of the moving distance in the precise forming method for multi-material and multi-process collaborative additive manufacturing

[0030] Description of the drawings: 1: Module 1; 2: Printing platform; 3: Device support frame; 4: Module 2; 5: Slide block table; 6: Module 3; 7: Curing agent spraying mechanism; 8: Resin spraying mechanism; 9: Drag chain; 10: Negative pressure pipe; 11: Sand suction device; 12: Hopper 1; 13: Hopper 2; 14: Roller; 15: Heating tube cover; 16: Hopper support frame; 17: Transducer; 18: Roller support frame; 19: Heating tube; 20: Upper screen; 21: Feeding device; 22: Shock absorber; 23: Lower screen. Detailed implementation manners

[0031] The present invention will be further clarified below in conjunction with the drawings and specific implementation manners. It should be understood that the following specific implementation manners are only used to illustrate the present invention and not to limit the scope of the present invention. It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to the directions in the drawings, and the words "inner" and "outer" respectively refer to the directions towards or away from the geometric center of a specific component.

[0032] Such as Figures 1-5As shown in the figure, a precise forming device for multi-material and multi-process collaborative additive manufacturing according to this embodiment includes a sand suction and lower sand integration mechanism, an inkjet printing mechanism, a feeding and compaction mechanism, a heating and bonding curing mechanism, a printing platform, and a main frame. The sand suction and lower sand integration mechanism consists of a sand suction device 11, a negative pressure pipe 10, a first blanking box 12, a second blanking box 13, a screen 20, a transducer 17, a material box support frame 16, a shock absorber 22, a second module 4, and a drag chain 9. One end of the negative pressure pipe 10 is connected to the sand suction device 11, and the other end is externally connected to a negative pressure device. The first blanking box 12 and the second blanking box 13 are fixed on the material box support frame 16. The shock absorber 22 is fixed between the material box support frame 16 and the second module 4. The drag chain 9 is fixed on the second module 4. The first blanking box 12 and the second blanking box 13 are externally connected to the transducer 17 and are equipped with a screen 20 inside. The transducer 17 is externally connected to an ultrasonic generator. The second module 4 is fixedly installed on the slider table 5. The inkjet printing mechanism consists of a third module 6, a curing agent injection mechanism 7, and a resin injection mechanism 8. The curing agent injection mechanism 7 and the resin injection mechanism 8 are fixedly installed on the third module 6. The third module 6 is fixedly installed on the slider table 5. The feeding and compaction device consists of a feeding device 21, a roller 14, and a roller support frame 16. The feeding device 21 is fixed on the bottom plate of the device support frame 3. The roller 14 is fixedly installed on the roller support frame 16. The roller support frame 16 is fixedly installed on the slider table 5. The heating and bonding curing mechanism consists of a heating pipe 19 and a heating pipe cover 15. The heating pipe 19 is fixed in the heating pipe cover 15. The heating pipe cover 15 is fixedly installed on the slider table 5. The main frame consists of a device support frame 3, a first module 1, and a slider table 5. The slider table 5 is fixedly installed on the first module 1. The first module 1 is fixedly installed on the device support frame 3;

[0033] Among them, the first blanking box 12 and the second blanking box 13 are composed of upper and lower parts. The upper half is a cylinder, mainly used for storing sand, and the screen 20 is located in the middle of the upper and lower halves. The lower half is two conical shapes. The upper cone one is used to flow the sand after vibration to the lower cone one. There is a lower screen 23 between the upper and lower cones. Here, the lower screen 23 is mainly used to break the arching of the sand in the upper cone at the upper cone opening. At the same time, when vibrating, the sand falls more scattered and the amount is small and does not block the lower cone. There is a processing groove at the contact between the lower cone one and the upper cone one to prevent the lower screen 23 from being too small to vibrate. The lower cone opening is smaller, which is conducive to precise fixed-point sand laying. The entire blanking box mainly realizes the falling of the sand and controls the sand falling amount through ultrasonic or mechanical structure vibration. The sand suction device 11 consists of three parts: a cylinder sleeve, an upper cone two, and a piston movement lower cone. The cylinder sleeve provides a sealed environment and supports the upper cone to collect the piston movement lower cone. The upper cone two is used to better collect the sucked sand to the negative pressure pipe opening and discharge the sand. The piston movement lower cone is divided into a lower cone two and a piston cylinder sleeve. The lower cone two moves up and down on the piston cylinder sleeve. Its main function is to precisely fix-point sand suction. When the pipe opening of the lower cone two is not above the printing area, it is 2.5 mm away from the printing surface;

[0034] Among them, a curing agent spraying mechanism 7 and a resin spraying mechanism 8 are respectively arranged on both sides of the module three 6; a blanking box one 12 and a blanking box two 13 are arranged on one side of the module two 4; and a sand suction device 11, a roller 14 and a heating and bonding curing mechanism are arranged between the module one 1 and the module two 4. The roller 14 is close to the module two 4, and the heating and bonding curing mechanism is close to the module one 1.

[0035] Among them, as Figure 9 shown, the distance between the sand suction mechanism and the blanking box one 12 is 35 mm, the distance between the resin nozzle in the resin spraying mechanism 8 and the curing agent nozzle in the curing agent spraying mechanism is 70 mm, and the distance between the blanking box one 12 and the curing agent nozzle in the curing agent spraying mechanism is 105 mm.

[0036] As Figures 6-9 shown, a multi-material and multi-process collaborative additive manufacturing precise forming device in this embodiment has the following forming steps:

[0037] Step (1): Divide the printed sand mold three-dimensional model according to the casting performance requirements and slice the model separately. The feeding device 21 feeds 70-140 mesh silica sand. The module one 1 drives the slider table 5 to move 5 widths, and the moving distance of each width is 70 mm. When the roller 14 rolls over the feeding device 21, the molding sand is rolled and spread on the printing platform 2. The module two 4 drives the curing agent spraying mechanism 7 and the resin spraying mechanism 8 to move. The curing agent spraying mechanism 7 and the resin mechanism 8 spray resin and curing agent according to the cast slice of 70-170 mesh silica sand in the divided model. After one layer of printing is completed, during its return journey, the heating tube performs radiation heating at 260 °C and 50 HZ.

[0038] Step (2): The module one 1 drives the slider table 5 to perform stage movement. The sand suction device 11 sucks sand according to the chromite sand slice of 70-140 mesh in the divided model. As Figure 9 shown, when the sand suction device 11 reaches the 5th width where the sliced area is located, it performs stage movement, and the moving distance of each stage is 2 mm. When the sand suction device 11 reaches the sand suction area in the slice, the lower cone descends 2 mm in the piston cylinder sleeve. After the sand suction ends in the 7th width, the lower cone rises 2 mm. At the same time, according to the slice information, the molding sand in the blanking box one 12 undergoes ultrasonic vibration and sand falling to fill the sand suction area until the blanking box one 12 finishes the 7th width and ends the stage movement. At the same time, the module two (4) drives the curing agent spraying mechanism 7 and the resin spraying mechanism 8 to spray resin and curing agent according to the slice information. After one layer of printing is completed, during its return journey, the heating tube performs radiation heating at 260 °C and 50 HZ.

[0039] Step (3): Perform the operation of step 2 until the single-layer multi-material sand mold printing is completed, and repeat the above steps until the overall sand mold printing is completed.

[0040] Among them, the width movement is carried out when the curing agent spraying mechanism reaches above the printing platform. The width is the length of the nozzle, and it is required that the nozzle length in the curing agent spraying mechanism is equal to the nozzle length in the resin spraying mechanism. The length of the printing area is 560 mm;

[0041] Among them, the stage movement starts from when the sand suction device reaches the sand suction area in the slice until the sand falling in the blanking box ends. At the same time, the control of the stage movement takes precedence over the width movement. The radius of the suction nozzle in the sand suction device is equal to the radius of the sand falling openings of the first blanking box and the second blanking box.

[0042] The technical means disclosed in the solution of the present invention are not limited to the technical means disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features.

Claims

1. A precise forming device for multi-material and multi-process collaborative additive manufacturing, comprising a main body frame, a printing platform, an inkjet printing mechanism, and a feeding and compaction mechanism. The inkjet printing mechanism is composed of Module III (6), a curing agent injection mechanism (7), and a resin injection mechanism (8). The curing agent injection mechanism (7) and the resin injection mechanism (8) are fixedly installed on Module III (6), and Module III (6) is fixedly installed on the slider table (5). The feeding and compaction device is composed of a feeding device (21), a roller (14), and a roller support frame (18). The feeding device (21) is fixed on the bottom plate of the device support frame (3), the roller (14) is fixedly installed on the roller support frame (18), and the roller support frame (18) is fixedly installed on the slider table (5). It is characterized in that: It also includes an integrated mechanism for sand suction and sand feeding, and a heating and bonding curing mechanism; the integrated mechanism for sand suction and sand feeding consists of a sand suction device (11), a negative pressure pipe (10), a first feeding box (12), a second feeding box (13), a sieve mesh (20), a transducer (17), a feeding box support frame (16), a shock absorber (22), a second module (4), and a drag chain (9). One end of the negative pressure pipe (10) is connected to the sand suction device (11), and the other end is externally connected to a negative pressure device. The first feeding box (12) and the second feeding box (13) are fixed on the feeding box support frame (16). The shock absorber (22) is fixed between the feeding box support frame (16) and the second module (4). The drag chain (9) is fixed on the second module (4). The first feeding box (12) and the second feeding box (13) are externally connected to the transducer (17). The second module (4) is fixedly installed on the slider table (5); the heating and bonding curing mechanism consists of a heating pipe (19) and a heating pipe cover (15). The heating pipe (19) is fixed in the heating pipe cover (15), and the heating pipe cover (15) is fixedly installed on the slider table (5); the main frame consists of a device support frame (3), a first module (1), and a slider table (5). The slider table (5) is fixedly installed on the first module (1), and the first module (1) is fixedly installed on the device support frame (3); where the first feeding box (12) and the second feeding box (13) are composed of upper and lower parts. The upper part is a cylinder, and the upper sieve mesh (20) is located in the middle of the upper and lower parts; the lower part is composed of two conical shapes. The upper cone one is used to direct the sand flowing down after vibration to the lower cone one. There is a lower sieve mesh (23) between the upper cone one and the lower cone one. This sieve mesh is used to break the arching of the sand in the upper cone one at the upper cone opening. At the same time, when vibrating, the sand falls more scattered and in a small amount, and does not block the lower cone one. There is a processing groove at the contact between the lower cone one and the upper cone one to prevent the lower sieve mesh (23) from being too small to vibrate; the sand suction device (11) consists of three parts: a cylinder sleeve, an upper cone two, and a piston moving lower cone. The cylinder sleeve provides a sealed environment and supports the upper cone collecting the piston moving lower cone. The upper cone two is used to better collect the sucked sand to the negative pressure pipe orifice and discharge the sand. The piston moving lower cone two is divided into a lower cone two and a piston cylinder sleeve. The lower cone two moves up and down on the piston cylinder sleeve. When the orifice of the lower cone two is not above the printing area, it is 2.5 mm away from the printing surface.

2. The precise forming device for multi-material and multi-process collaborative additive manufacturing according to claim 1, wherein: The transducer (17) is externally connected to an ultrasonic generator.

3. The precise forming device for multi-material and multi-process collaborative additive manufacturing according to claim 1, characterized in that: On both sides of the third module (6), there are respectively a curing agent spraying mechanism (7) and a resin spraying mechanism (8); on one side of the second module (4), there are a first feeding box (12) and a second feeding box (13); and on the other side, there is a sand suction device (11); among them, the roller (14) and the heating and bonding curing mechanism are located between the first module (1) and the second module (4). The roller (14) is close to the second module (4), and the heating and bonding curing mechanism is close to the first module (1).

4. The precise forming device for multi-material and multi-process collaborative additive manufacturing according to claim 1, characterized in that: The distance between the resin nozzle in the resin spraying mechanism and the curing agent nozzle in the curing agent spraying mechanism needs to be an integer multiple of the width.

5. A forming method of a multi-material and multi-process collaborative additive manufacturing precision forming device according to any one of claims 1-4, characterized in that: The forming steps are as follows: Step (1): Divide the printed three-dimensional sand mold model into multiple groups according to the casting performance requirements and perform grouped slicing on the model. At the same time, the feeding device feeds sand. Module 1 drives the slider table to move multiple widths. When the roller rolls over the feeding device, the molding sand is rolled and spread on the printing platform. Module 2 drives the curing agent spraying mechanism and the resin spraying mechanism to move. The curing agent spraying mechanism and the resin spraying mechanism spray resin and curing agent according to one group in the divided model. After one layer of printing is completed, infrared heating is carried out during its return journey. Step (2): Module 1 drives the slider table to move in width. The sand suction device accurately sucks sand according to the second group of sliced areas in the divided model. When the sand suction device reaches the sliced area, the lower cone descends a certain distance in the piston cylinder sleeve. After sand suction is completed, the lower cone rises a certain distance to complete the sand suction procedure. At the same time, according to the sliced information in the first hopper, the second type of molding sand particles are filled in the sand suction area by ultrasonic or mechanical vibration for sand falling. Then, module 2 drives the curing agent spraying mechanism and the resin spraying mechanism to spray resin and curing agent according to the sliced information. After one layer of printing is completed, infrared heating is carried out during its return journey. Step (3): Perform the operation of step (2) until the single-layer multi-material sand mold printing is completed, and repeat the above steps until the overall sand mold printing is completed.

6. A precise forming method for multi-material and multi-process collaborative additive manufacturing according to claim 5, characterized in that: In step (1), the three-dimensional model of the multi-material sand mold is divided according to the casting performance of the casting. The molding sand used in the feeding device is coarse silica sand, and the molding sand such as chromite sand, fine silica sand, and zircon sand is dropped by the first hopper or the second hopper.

7. A precise forming method for multi-material and multi-process collaborative additive manufacturing according to claim 5, characterized in that, The temperature of the heating tube is between 200°C and 300°C, the radiation frequency is 10 - 100 HZ. At the same time, the heating temperature is feedback-regulated according to the return moving speed. At the same time, the temperature of the heating tube needs to ensure that the molding sand capable of spraying resin and curing agent can quickly undergo an adhesive reaction to achieve curing between the molding sand particles.

8. A precise forming method for multi-material and multi-process collaborative additive manufacturing according to claim 5, characterized in that When the curing agent spraying mechanism reaches above the printing platform, it moves in width. The width movement length is the width of the printing nozzle, and it is required that the length of the nozzle in the curing agent spraying mechanism is equal to the length of the nozzle in the resin spraying mechanism. The length of the printing area is an integer multiple of the width movement length. The sand suction device starts to perform stage movement within the width where the sand suction area is located in the slice until it reaches the width where the sand falling area is located in the first hopper or the second hopper. The stage movement length is the diameter of the lower cone opening in the sand suction device, and the width movement length is an integer multiple of the stage movement length. The diameter of the lower cone opening in the sand suction device is equal to the diameter of the lower cone opening of the first hopper and the second hopper. At the same time, the control of the stage movement takes precedence over the width movement, and the stage movement must complete the entire width movement length.

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